Competitive Relationships between Tree Species of Scalesia (S. pedunculata, S. cordata, S. microcephala) and Introduced Plants (Cinchona succirubra, Psidium guaiava, Lantana camara) with Reference to Regeneration Mechanism of Scalesia Forests in the Galttpagos lslands
Yoshikazu SHIMIZU*
Synopsis
Regeneration mechanism of Scalesia forests and competitive relationships between tfuee species of tree &alesia (5. pedunculata, S. cordata, S microcephala) and some introduced spcies (Cinchona succintbrg Psiilium gaajava, Lantona carnara. etc.) were studied in 80 plots ofsix siteg in Santa Cruz, Isabela and Floreana. Especially, the oneyear change ofvegetation after the 1994 fire was survcyed in connection with the regeneration of S. cordan forest and the invasion of Psidium guajava in Isabela. The ecology of shrubby Scalesia (5. afinis) was also studied in 8 plots of four sites in the same islands. Two regeneration types were detected: ( 1) Synchronous Type in moist for*ts with closed canopy: old trees of Scalesia die synchronously because of much rain at an Bl Niflo event, new seedlings of Scalesia germinate all at once, and tley make an even-aged population, and (2) Continuous Type in drier for6ts with sparse canopy: regeneration ofscalesia trees occur turn by turn in canopy gaps continuously, making a different-aged population. Cinchona succirubm is spreading rapidly to the vast Highland area in Santa Cruz, but it has not invaded theS. pedunculato for6t with closed canopy yet' because it needs bright and moist condition for establishnent. It is speculated that Cinchona may invade the S pedunculara forest rapidly at the next El Nifro event when the canopy collapses all 8t once. Psidium gttajava is making a vast secondary forest on the windward slope of Sierra Negra' Isabela. The 1994 fire burned a large area in this region. New shoots (l-2 m hieh) sprouted from the base of dead stems of Psidium, while no burnt trees of S. cordata hsld such new shoote. So the fire accelerated replaceme nt of S cordata 1lirth Psidium. S. cotdata saplings (2-3 m high) were growing near adult trees which had survived the fire at forest margins and fire'break belts. Small parches of S. cordaU forest may recover in these places. S. micrccephala makes a sparse foreet on the north-east slope of Alcedo, Isabela. No introduced tree and ehrub species were found there. Lantana camom covers tlc ground of S pedunculata forests densely in Florcana. This may prevent establishment of S. pe&nctlata seedlings at the next regeneration event' resulting in dirappearance of the forests. The distribution of tree Sbalesrd and S, cfinir never overlap with each other. Low seed dispersibitity.of Scalesia s€ems to be related with this distribution pattern. Compared with the introduced plant species, the rapid growth rate of seedlings and eaplings is a great advantage of tee Scalesia, but the low seed dispersibility is the largeet weak point. If wc hclp tree Scalesia by making an olrcn land and dispereing seeds at the appropriate time, it would be possible to restore,Scclesia forest in disturbed area.
Pacific Ocean, 960 km west of the South Ameri- I. Introduction can Continent. They form a province of the Republic of Ecuador, consisting of sixteen main 1. Location & Geology islands and more than 40 islets with a total land The Galfupagos Islands are located in the east area of 7882 km2 (Fig. 1). Seven islands have an
* Professor, Department of Natural Sciences, Komazawa University, Tokyo.
一- 23 -― Regional Views No. 11 1997
DARWIN 屁b P:NttA
S woLF 6 0 GENOVESA 92° W MARCHENA
。 。 ′/こ 漁 ―――――――――― Foユ F p._.| ふ km ―― ――――
Ｉ Ａ Ｒ Ｉ Ｉ Ｉ １
０ ｒ SAN CRiSTOBAL SA需電 選電‖lttA Cerro― 二 γ Lrt」 Vi二 二aコ己二 :SA:ELA I FLOREANA 静 ESPANOLA a“ 二as C 90°
Fig. 1. Geographicel map of the Galipagos Ishndr. Broken lines on the nap show the 200n, 500n and 1000 n contours ftom the sea level.
Table 1. Islands of the Galipagos Islands area of more than 100 km2 lTable 1). The larg- est, Isabela, has an area of 4588 km', more than Name Area (k-') Altitude (m) the total area of all the other islands combined. Isabela 4,588 1,707 The islands are dispersed just under the Equator, Santa Cruz 986 864 ranging from approximately 1"40'N to lo25'S Fernandina 642 1,494 latitude and from 89" 20'W to 92o 00'W longi- Santiago 585 907 tude. The highest peak in the archipelago is 1707 San Cristobal 558 739 m of Volcan Wolf in Isabela. Floreana 173 640 The islands have been formed by the activity Marchena 130 343 of Espafiola 60 206 the hot spot which seems to be located at the Pinta 59 777 north-western end of the archipelago. The islands Baltra 27 100 are made up of basaltic lava flows built one upon Santa F6 24 259 another and deposits of volcanic ash, cinders, and Pinz6n 18 458 scoria thrown out of craters during eruptions Genovesa 14 76 (Jackson 1993). Three rows of island chains are Rabida 5 367 detected running from the northwest to the south- Wolf 1。 3 253 east: (l) Pinta-Marchena-Genovesa-San Cris- Darwin 1.1 168 tobal, (2) Santiago-Rabida-Pinz6n-Santa Crvz- Santa F6-Espaflola, (3) Fernandina-Isabela- Floreana (Itow 1983). According to the Plate
一- 24 -一 Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu)
Tectonics theory, the present islands formed within 2.8-6.3 million years on the Nazca Plate have been moving from the northwest to the southeast at a speed of 3.7 cm per year, so the older islands with eroded landscapes are located at the south-eastern part of the island chains, while the younger ones with active volcanoes at part Recently a the north-western (Geist 1996). o .'- 10 million-year-old submerged island was dis- i;:T i::; covered east of San Cristobal, so the age of the Fig. 2. Monthly mean temperatures and preci- archipelago must be older than the present islands pitation recorded from 1965 to 1994 at CDRS (Christie at al. 1991). There are historical re- Meteorological Station, Santa Cruz. cords of volcanic eruptions in Pinta, Santiago, Fernandina and Isabela. As water percolates (a) rapidly to considerable depths, there are virtually
（ no permanently flowing streams with the excep- Ｅ ５ ０ ０ ） ８ tion of a small stream in San Cristobal. ０ ０ ０ 引 一 ｏ 一 「 ５ ０ ０ ， ｏ ｏ Climate ０ ０ ０ 2. と The climate of the Galiryagos Islands is excep- tionally cool and dry for equatorial islands due to the influence of the cool Hunbolt current running through the islands from the south. The annual □ 1969 層調 1970 average temperature and precipitation is 23.9"C and 473.8 mm (1965-1994) at CDRS Meteoro- (b) logical Station, Puerto Ayora in Santa Cruz (Fig. 2). Two seasons are detected: (1) rainy season from January to June with sunny sky, hot temper- 目 ature and occasional squall, and (2) dry (garua) season from July to December with cloudy sky, cool temperature and little rainfall (Jackson
1 ee3). The south-east trade wind is prevailing and the Hunbolt current is dominant in the dry season. Fig. 3. Precipitation of the Galipagos Islands As the air cooled by the ocean current makes an (a) Altitudinal change of precipitation on the inversion layer at the altitude of 300 m-600 m, southern slope of Santa Cruz in 1969 and 1970. ascending cloud is suppressed at this height and Drawn from the data of Werfr (1979). (b) brings precipitation to the mountain slope (Fig. Annual change of precipitation at CDRS 3a). But the lowland area remains arid. The Meteorological Station, Santa Cruz. windward side of the islands gets far more precip- itation than the leeward side. The difference in rain fall is a main cause of the difference of drought sometimes hits the Islands. The occa- vegetation between the windward and the leeward sional occurrence of El Nifro and drought has sides. much influence on the life of plants and animals In the rainy season, the south-east trade wind in the Galhpagos. becomes weak and the warm Panama Basin flow comes closer to the islands. So the sea tempera- 3. History ture arises and the inversion layer disappears, The Gal6pagos Islands were discovered by bringing the typical tropical weather with sunny Tom6s de Berlanga accidentally in 1535. For skies and occasional squall. When the sea temper- many years the islands were used chiefly as a base ature continues to be unusually high once in of pirates, and later as a port of call by whalers several years, the total rainfall becomes 5 times for repairs and capturing tortoises for fresh meat. and more larger than usual years (Fig. 3b). This Scientific collection was done in the first quarter event is called "El Nifio". On the contrary, severe of the nineteenth century. Charles Darwin visited
一- 25 -― Regional Views No. 11 1997
four islands of the archipelago on the voyage of The 229 species (42.3Vo) out of the 541 species HMS Beagle from September 15 to October 20, are endemic to the Galiryagos. Progenitors of 1835. He collected 209 plant specimens which 94Vo of the non-endemic natives and 87Vo of the was the primary foundation for subsequent work endemics might have come from Tropical Amer- on the vascular plants of the islands (Wiggins & ica and the Andean region including pantropical Porter l97l). It is famous that he got an inspira- elements which are distributed in both the Amer- tion of evolution theory here which materialized ican and the Old World Tropics (Porter 1984). later in his book "The Origin of Species". Of the 7 endemic flowering plant genera, adaptive The history of human establishment is as fol- radiation resulted following a single original in- lows: San Cristobal has been occupied continu- troduction occurring in four genera: Darwiniotha- ously since 1869, the south-eastern part of Isabela mnus (2 spp., 4 subsp.), Lecocarpus (3 spp.), has been inhabited since 1893, Floreana has been Scalesia (15 spp. 7 subsp. 4 var. including S. inhabited intermittently since early the 19th cen- gordilloi which was described in 1986), and Jas- tury and continuously since 1929, and Santa Cruz minocereus (1 sp., 3 var.) (Porter 1984). Some of was colonized in the middle 1920's (Wiggins & the introduced species such as Psidium guajava, Porter I97I). Some islands were used as settle- Cinchona succirubra, and Lantana camara have ments of prisoners from the mainland until 1959. become wild and they are invading the native Many exotic plants and animals were introduced vegetation and giving much influence on the during those days (Latore 1990). native species (Schofield 1989, Lawesson 1990). The four islands in the archipelago are inhabit- There are no native land mammals except a few ed now. They have a port town on the coast and small bats and mice in the Galfupagos. Giant a few inland villages at a higher elevation with tortoises and land iguanas occupied the niche of moist condition good for cultivation and ranch- the large mammal herbivores. But they are ex- ing. The entire archipelago except towns and tinct or endangered at present in many places, farm lands was designated as a National Park in and instead, introduced mammals such as goats, 1959. Academy Bay at Puerto Ayora, Santa pigs, cows, donkeys, horses, dogs and cats have Cruz, has been the home of the Charles Darwin spread all over the islands giving serious damage Research Station (CDRS) since 1964, which has to native plants and animals (Hoeck 1984, Scho- been continuing the activities of research and field 1989). protection of the Gal6pagos nature. The unique eco-tourism of the Galfupagos was founded in the 5. Vegetation late 1960s (Itow 1992, Sayama 1995). The The vegetation of the Gal6pagos Islands is ba- number of tourists has been greatly increasing sically determined according to the three main since 1980s (Jackson 1993). At the same time, environmental factors: ( 1) island age (old-new) the number of immigrants coming from the main- which affects land forms (degree of erosion) and land is increasing rapidly. The total population is depth of soils, (2) altitude (low-high) which about 17,000 in 1996. makes a gradient of temperature and moisture in part, and (3) aspect (windward-leeward) which 4. Flora and fauna determines the amount of rainfall. Wiggins and The modern flora of the Galfupagos Islands was Porter (1971) proposed the six altitudinal zona- compiled by Wiggins & Porter's "Flora of the tion of vegetation according to the dominant Gal6pagos Islands" in 197 L Native plants are species groups; littoral, arid, transition, Sca lesia, derived from ancestors which accomplished a Miconia, and fern-sed ge zones from the coast to long-distance dispersal from other areas in the the mountain summit. Werff ( 1980) added past. The 541 species (including subspecies and "Brown vegetation" between Scalesia and Mic- varieties) of vascular plants which has probably onia vegetation in Santa Cruz. Itow (1985) ad- arisen from 413 original introductions are native mitted five zones ecologically; coastal, dry low- to the Galfupagos, and additional 195 species have land, transitiogal, moist mountain, and highland been brought by man since the discovery of the zones. Hamann (1981) also classified the vegeta- islands (Porter 1984). According to Carlquist tion into nine formations according to the veg eta- (1974), the methods of the long-distance dispersal tion structure. Vegetation maps of all islands for the ancestral plants in the Gal6pagos Islands were published by INGALA et al. in 1989. I propose and use six vegetation zones in this :::"1'"1*:"J:',::a paper as follows: (1) Littoral zone which appears
一- 26 -― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimrzu) along the coast and consists of four mangrove tree species of Scalesia and associated species such T. plants such as Rhizophora mangle, Laguncularia as Psychotria rufipes, Tournefortia rufosericea, scouleri, racemosa, Avisennia germinans, and Conocarpus pubescens, Zanthoxylum fagara, Croton Psidium errectus together with Hibiscus tiliaceus, Hippo- Pisonia flortbunda, chiococca alba and is on mane mancinella, and Maytenus octogona on galapageium; (5) Moist-scrub zone which slopes rocky bay area, and Ipomoea pescaprae, Scaevola the thin-soiled upper part of mountain covered plumeri, Lycium minimum and Sesuvium portula- comparable to "subalpine zone" and is in castntm on sandy beaches; (2) Arid zone which with scrubs like Miconia robinsoniana scrub covers vast lowland area made of exposed lava Santa Cruz and San Cristobal, and (6) Highland part mountains and is composed of arid-tolerant trees and shrubs zonewhich is on the uppermost of of such as Opuntia sPP., Jsminocereus sPP., Bursera comparable to "alpine zone" and is composed graveolens, Parkinsonia aculeata, Scutia pauci- Pteridium aquilinum thicket, or herb-grass mead- howellii and Cya- flora, Cordia lutea, Castera galapageia, Acacia ows with patches of Pernettya The elevational rotundiana, Prosopis iuhflora and Erithrina vel- thea weatherbyana near summits. tina; (3) Semi-arid zone which is a transitional range of each zone depends on the age and size zone between the Arid and the Moist-forest (height) of the islands and aspects of the slopes. plants a big problem zones, and is charactetrzed by the disappeatance Invasion of introduced is of Opuntia spp. and the occurrence of Trema for conservation of native vegetation in oceanic Cronk micranta and Psidium galapageium; (4) Moist- islands of the world (see Stone et al. 1992, Islands, some forest zone which is shrouded by cloud frequently & Fuller 1995). In the Galapagos into and is covered with Scalesia forests consisting of introduced plants are invading aggressively
わ
//A^',s. microeePhara
TIAG0 9。 日| 一km
ヽ
^ごヽ ヽ ヽ ゝ、_ノ ゝ ヽ 0｀ CRISTO瑯 ヽ
,S. peduneuJ'ata ,S. cordata
(A-F). Fig. 4. Distribution of three species of tree Scalesia and the location of study sites
一- 27 -― Regional Views No. 11 1997
native Scalesia forests taking the place of Scalesia on trunks and ground floor for each plot. in the Moist-forest zone, thus the sca lesia forests I put a l0 m X 10 m quadrat in each plot (the are disappearing from the Islands. Invasion of shape and size were changed in some plots). Four introduced plants is closely related with regenera- layers (Tree: T1, Sub-tree: TZ, Shrub: S, Herb: tion mechanism of scalesra forests and character- H) were detected in each quadrat according to istics of introduced species. So I studied the the height of trees, shrubs and herb. The number regeneration mechanism of Scalesia forests made of layers decreased in shrubby scrubs. coverage of the three species of tree scalesia: s. peduncu- percentage of each layer was estimated. Light lata in Santa craz and Floreana, and s. cordata intensity was measured by a handy illuminance and S. microcephala in Isabela (Fig. 4). I also meter (Topcon IM-3) on the forest floor and at a investigated competitive relationships between neighboring open place in some plots to calculate the sca lesia species and some introduced plants: the relative light intensity. Psidium guajava in Santa cruz,Isabela and Flore- f measured a DBH (diameter at breast height) ana, Cinchona succirubra in Sant a Cruz, and Lan- of all individuals with a height more than Z m, tana camara in Floreana, which have been invad- and also measured a diameter at a height of o.z m ing the Scalesia forests to much extent. if necessary. I counted the number of tree sap- A large area in the southern part of Isabela lings and shrubs whose height was between 0.5 m burned from April through June in 1994 (Mar- and 2 m. quez et al. 1994). I surveyed the influence of the Locations of all woody individuals (0.5 m( in fire on the vegetation as a member of Japanese height) were mapped, and crown projection was Mission sponsored by JAICA and Environmental drawn on the map for all canopy-making trees. I Agency in June, 1994 (JICA 1994). It was about also drew a transect figure of the forest along a one year after the fire when I visited the place this center line of the quadrat. time. so I studied the one-year change of vegeta- As for herbaceous species and seedlings of tree tion after the fire in connection with the regener- species, names were recorded with relative abun- ation of scalesia cordata forest and the invasion dance within a quadrat which was rated tenta- of Psidium guajava. tively as follows; 4: many and widely distributed, This study was conducted in the overseas Re- 3: many but narrowly distributed, 2: not so many, search Program of Komazawa university in 1: rare. I 995. These measurements and drawings were partly omitted in some plots due to limited survey time ff. Methods and other conditions. The number of individuals and the basal area of I stayed in the Galhpagos Islands from April 6 all tree and shrub species, and the relative abun- through June 10, 1995. Six study sites were dance of herbaceous species and seedlings of chosen in the three islands as follows:Santa cruz: woody species as well as altitude, plot size, crown Site A (Cerro Crocker: 10 plots) and Site B (Los height, and coverage of each layer in all surveyed Gemelos: 10 plots), Isabela: Site C (Alemania: l5 plots are shown in Appendix. plots), Site D (Velasco: ZA plots) and Site E Nomenclature follows Lawesson et al. (1987). (Alcedo: 13 plots), and Floreana: Site F (Cerro Pajas:l2 plots) (Fig. 4). I put 80 plots in rotal in flf. Results the six sites which ( 1) represent vegetation struc- ture and composition of an area, (2) show regen- 1. Site A eration mechanism of scalesia forests, or (3) ( 1) Location present invading process of introduced species. santa cruz is the second largest island in the In addition to them, r surveyed the lowland arid archipelago. It has a conical shape with the vegetation with a shrubby scalesia (s. affinrs) in highest peak (Alt. 864 m) of Cerro Crocker at the four sites; , Santa Cruz: Site SC (l plot), Isa- the center of the island (0" 3g ' 57' 'S, 90" I g, 41, bela: Site IBa (2 plots) and IBb (4 plots), and W). The island is located in the middle of the Floreana: Site FL (1 plot). geological chains (see Fig. l ), thus it has no Recorded were location (latitude and longitude active volcano, and the mountains are moderately by GPS: Panasonic KX-G5500), altitude (bV eroded. Puerto Ayora, center of eco-tourism, is Thommen's altimeter), aspect, inclination, condi- located on the south coast. The town is connect- tion of basal rock or soil, and amount of epiphytes ed to the airport at Baltra on the opposite side of
一- 28 -― Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) the island with a partly-paved car road. Two shrouded by fog. On the ridge near the summit of villages, Vella Vista and Santa Rosa, are on the Cerro Crocker, a wind-swept dwarf scrub compa- way. Site A is located to include both north and rable to "alpine scrub" is formed where Pernettya south slopes of Cerro Crocker and its main ridge howellii and Cyanea wetherbiana appear- Sphag- running from the east to the west (Fig. 5). num bogs are also found in concave places Scalesia pedunculata forests have almost been around the ridge. An introduced tree: Cinchona destroyed and pasture lands go up to about 450 m succirubra has been invading the area from the in altitude on the south (windward) side of the south up to the ridge. So many trees of Cinchona island. A thin belt of Miconia robinsoniana thrck' afe found in the Moist-scrub and the Highland et (Moist-scrub zone) is left around Media Luna zones, and it seems to be about to invade the between 450 m and 600 m in altitude and above it Scalesia forest beyond the ridge (Fig. 5). appears a vast fern & grass meadow (Highland zone) with Pteridium aquilinum on a plateau (2) Scalesia pedunculata forest spreading up to the main ridge about 800 m. The Scalesia forest is very simple in structure Beyond the ridge, Scalesia forest is widely dis- and species composition. Plot A1 and Plot A2 tributed on the north (leeward) side of the island. show the typical Scalesia forest in Site A. The Prevailing wind blows from the south to the crown (T 1) layer is composed of only Scalesia north. The upper part of this atea is frequently pedunculata. Tree crowns are almost even in
Crater 幸 0 1 km Ridge l l l Tra■ ■ °f 1,鵬 盤 SCALESIA FOREST
MICON=A
PASTURE ―
Fig. 5. Vegetedon zones and the invasiot ol Cinchona suecirubra in Stte A. Modifled from ltor (1983).
―- 29 -― Regional Views No。 11 1997
PLOT Al ∽ 司 く ⊃
Ｑ ＞】 ∩ｚ】
」 〇 “ 国 口Σ⊃Ｚ
6-9 9-12 12-15 DBH CLASS (cm) □ alive l■ dead
∽５ 司０ く ⊃
Ｑ＞一４ ０ ∩Ｚ一 」 〇ぼ国国Σ⊃Ｚ
３ ０
２ ０
１ ０
6-9 9-12 Fig.6。 DBH hおtograms or Scaras,α ガ c“Jara DBH CLASS (cm) μ in Plots Al and A2。 ““ □ alive ■ dead
-5m
Fig.7. Profle diagam of Scalqia forest in Plot A1. Keyc to abbreviations: Py, Psychdria rufrryi S, scaleda peduncuhtai Tf, Tountefortia rufovrica. underlined symbotc ghow dead treec.
height. The T2-layer is usually vacant. The DBH crown layer is nearly tOOVo, but crowns never histograms have an uni-modal distribution, and overlap with each other (Fig. 8), so it is not so dead trees are concentrated to thin stems (Fig. 6). dark under the canopy. The relative light intensi- Almost all individuals of scalesia have one slen- ty is 7.6% in Plot A1. der bole with no sprouts at the base (Fig. 7). The Shrub layer is also very poor. Psychotria These facts suggest that the population started all rufipes and Tournefortia rafosericea are rather at once in the near past and dead trees are the abundant among them. The forest floor is very result of recent self-thinning. The coverage of moist and mossy, and many fern species are found
-30- Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu)
10mX10m
x
.fg
Fig.8. Crown projectioi diagran of Scalesia forest in Plot A1. Keys to abbreviationg: S, Scchia pedurcalata.
Mt. Puntudo
Invasion of Ci,nehona
thicket Pteridj-um Scalesia forest
Soil Fig. 9. Invasion pattern of Cinchona succirubra on a slope near Mt. Puntudo.
here compared with other vegetation types. Espe- forest as a whole takes on an mossy appearance. cially, big ferns such as Therypteris balbisii and T. Some epiphytes such as Peperomia galapagensts oligocarpa feature the Herb-layer of the forest. and Asplenium auritum attach to the mossy Stems and branches of Scalesia trees are covered trunks and branches. No seedlings and saplings thickly with moss and lichen (Photo l). The of Scalesia are found in the forest, though adult
3l Regional Views No. 11 1997 trees seem to produce many seeds in the canopy dium attains to 2 m high there, and the density of every year. Seedlings and saplings of Cinchona petioles is 32-39lsq. m (35.2/sq. m in average). succirubra are also not found in the Scalesia The relative light intensity is l.|Vo. Almost all forest, even though many Cinchona trees which fronds were alive and green in the same day. produce a lot of wind-dispersed seeds are dis- Plot A3 and Plot A4 show the Cinchona stands tributed just outside of the Scalesia forest. located on the upper part of the slope. The height class distribution of Cinchona has a mode be- (3) Invasion of Cinchona succintbra tween 4 m and 5 m (Fig. lOa). The DBH class Cinchona succintbra appears only at the alti- histogram also shows uni-modal distribution with tude of 350 m and above in Santa Cruz, because it a mode between 3 cm and 6 cm (Fig. 10b). Even needs moist conditions to establish. Cinchona is the largest tree was 6 m in height and 11.5 cm in invading the Highland zone widely (Photo 2). DBH, though Cinchona covld become a tall tree The density of Cinchona seems to be inversely by nature. Almost all trees are growing well with related with the amount of Pteridium aquilinum. no serious damage on their crowns. These facts Fig. 9 shows a transect from the peak of Mt. suggest that these trees are all young and the Puntudo (0o 39'05"s, 90o 2o'21"w, Alt. 780 m) invasion occurred relatively recently. Cinchona to the dense Scalesia forest on the plateau through matures very fast. Even a young tree of 1.8 m the Pteridium thicket in Site A. Cinchona has high has some flowers. Seeds with a membranous invaded densely the upper part of the slope where wing are very light and easily blown off by wind. the density of Pteridium is low because of thin Almost all trees have already produced flowers soils (basal rocks are exposed everywhere). The and fruits. However, saplings of Cinchona ate height of Pteridium thicket is 0.7{.8 m and the rarely found in the area except for a few places density (No. of petioles) is 1l-23/sq. m ( 18.4/ where they are growing around mature trees sq. m in average). The relative light intensity is (Plot A4) (Fig. l1). I could find Cinchona 2.8Vo on the floor of the thicket. Nearly half of seedlings less than 0.2 m high nowhere in this the fronds of Pteridium were dead when I ob- area. So the invasion of Cinchona seems to be served them in April. On the contrary, Cinchona periodic rather than continuous. This area is is distributed only sparsely in the lower part of the frequently shrouded by fog, but it occasionally slope where soils are well developed and the Pteri- becomes dry because of thin soil (exposed basal dium thicket covers the ground densely. Pteri- rocks). The occasional aridness and the dense thicket of Pteridium may prevent Cinchona from (a) continuous regeneration. plor A4 Cinchona has the ability to produce sprouts from the base of a tree. It usually takes a multi- stemed growth form (Fig. I2). One individual over 1 m high has 3.4 stems in average in and around Plot A4. Young trees produc e honzontal branches which results in a cylindrical shape of the addition, produces vertical 2-3 3-4 crown. In it HEIGHT CLASS(m) shoots from a fallen stem and then each shoot has 目 Cinchona adventitious roots at the base (Fig. 13). So we find small individuals which are connected to り parent tree under the ground (Plot A8) (see Fig. PLOT A4 1e). ∽ 蜜 A former plantation of Cinchona is left at the ≦ 汽 altitude of 450 m near Media Luna on the wind- Ｚｂ ward side of the mountains. It seems to be one of “ 壁 the original source places from which Cinchona invaded the upper Highland zone. Plot A5 ２ into has a few tall Cinchona trees over 15 m in height DBH CLASS(cm) occurring sparsely (Fig. l4), and a lot of saplings 雲 Cinchona most of which are lower than 4 m high growing Fig. 10. Height and DBH histograms of C,■ ‐ under the canopy (Fig. 15). It is strange that chona young forest in Plot A4. medium-sized trees are rare. This may be the
一- 32 -一 Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu)
丁2:● Sap I ing: x Fig. 11. Crown projection diagram ol Cinclnna yourg forest in Plot A4. All individnrk in the figure are Cittchona succirubra. εl C Ci ミ Ｆ 講 Fig.12. Profile diagram ol Cinchona young forest in Plot A3. Keye to abbreviations: Ci, Cinclnna succirubm; Pfr , Ptefidiam aquilinum. result of eradication efforts in the past (Tuoc windward side, the forest takes on a mossy ap- 1983). The crowns of tall trees are cylindrical, pearance. The forest floor is also moist and and the amount of leaves are scarce, thus the mossy. Many Cinchona seedlings are found on relative light intensity is not so low on the floor the floor, especially on the moss mats. The densi- (I4.2Vo under the canopy and 27.8Vo in the ty of seedlings, whose height is between 0.1 m and canopy gap). As this place is located on the 1 m, is l4-36/sq. m (Average: 22/sq. m in ten 一- 33 -一 Regional Views No. 1l 1997 → ― ―― ―Ｉ Ｃ ＩＩ Ｉ Ｉ） Fig. 13. Growth forms of Cinchona succirubra in various developmental stages. T1 :O T2:e S:x dead:r 10mX10m Fig;14. Crown projection .lirgran ol Cinchona forect in Plot A5. All individuals ercept rcbhaoniana (Abbr.: M) are Cinctana succirubra. 34 Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) Fig. 15. Profle diagram of Cinchona forest in Plot A5. Keys to abbreviations: 6, Cinchona srrccirubmi M, Miania robinsoniana. T1 :So,Ci a S:x dead:r Fig. 16. Crown projection diagram of transitional part between Scalesia forest arnd Cinchona young forest in Plot A6. Keys to abbreviations: Ci, Cinchona succirubra; Ptr, Pteridium aquilinuni S, Scalesia pedunculata; Zf, Zanthoxylum fagara. I sq. m quadrats). As this place originally belongs dispersed into the Sca lesia forest frequently. On to the Moist-scrub zone, some individuals of Mic- the other hand, only a few Cinchona saptings were onia robinsoniana are left in the Shrub layer of the found within the Cinchona forest, probably be- forest. Seedlings of Miconia are also found on the cause the dense thicket of Pteridium ptevents new floor. In addition, I found many seedlings and establishment of seedlings. I could not find any saplings of Cinchona growing along a sunny trail seedlings and saplings of Sca lesia in both the outside the forest. Cinchona and the Sco lesia forests. Matured trees There is a place where a small patch of Cincho- of Cinchona are all vigorous, while some of the na forest is just adjacent to a wide Scalesia forest Scalesia trees located on the edge of the forest are on a mountain slope. I put a belt transect (Plot A damaged or dead. 6) through the border of the two forests (Fig. 16). It is noteworthy that no saplings and seed- (4) Relationships between Scalesia and other lings of Cinchona are found in the Sca lesia forest, introduced plants even though seeds of Cinchona must have been There is a small patch of Scalesia forest on the 35 Regional Views No. 11 1997 Fig. 17. Profile diagram of Scalesia forest isolated on a slope in Plot 47. Keys to abbreviations: Pan, Panicum maximum; Ptr, Ptcridium aquilinum; Py, Psychotria rufipes; S, Scalesia pedunculata; Tf, Tournefortia rufosericea. PLOT A7 ヨ 賓 ⊃ ∩ ＞ 園 ‘ δ 縣 国 晨 ブ 0-3 3-6 6-9 9-12 12-15 15-18 18-21 DBH CLASS (cm) Fig. 18. DBH histogram of Scalesia pedunculata □ alive l■ dead in Plot A7. north slope of the mountains (Plot A7). The completely in this place. upper part is bordered by a dense Pteridium aqui- As seeds of Psidium guajava are dispersed by linum thicket , 2 m high, and the lower part is cut birds and feral animals, the spreading speed seems off by a Panicum m&ximum community, 1.5-2 m to be slower than Cinchona which bears wind- high (Fig. l7). The upper and lower borders are dispersed seeds. However, Psidium is invading clearly divided, and neither Pteridium nor Pan- the Site A area slowly but steadily. A vast Psi- icum can invade the forest floor, because they can dium forest (deserted plantations in private not get enough light under the canopy. The lands) goes up to about 540 m in the windward distribution pattern of DBH histogram is similar slope near Media Luna. There are many small to the typical Scalesia forest (Plots Al and A2) patches of Psidium in the Highland zone and in (Fig. 18). Most of the thin stems less than 6 cm open places adjacent to the Scalesia forest, though DBH are dead. Although the average DBH of the number of individuals is far less than that of living trees in Plot A7 is larger than those of Plots Cinchona. Similar to the situation of Cinchona,I Al and A2, these forests seem to have established could not find any seedlings and saplings of Psi- at the same time. When the forest die all at once dium under the closed canopy of Scaleslc forest. next time, will this forest be able to regenerate Plot A8 shows one of the small patches of successfully ? If the invasion of Pteridium and Psidium trees in the Pteridium thicket (Fig. l9). Panicum into the open place by underground Psidium has a good sprouting ability and it usual- stems su{pass the growth of Scalesra seedlings, the ly takes a multi-stemmed growth form, but Psi- Scalesia forest may reduce its area or disappear dium in Plot A8 has no such sprouts (Fig. 2O). 一- 36 -― Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) A S:x 10mX10m (Abbr.: Fig. 19. Crown Drojection dlagram of Plot A8 showing the invasion oi Cinclwna succirubra Ci) and Psiilium guqjava (Abbr.: Pj) in a dense thicket of Rtzrdium aquilinum (Abbr.: Ptr). Fig.20. Proffle diagram of Plot A8 showing the lnvasion ol Cinchona succirubm (Abbr.: CD tad Psidium gu4java (Abbr.: Pj) in a dense thicket ofPtzriilium aqailinum (Abbr.: Ftr). On the contrary, Cinchona trees in the plot have a tree except for just under the dense canopy (Fig. multi-stemmed growth form. They have several 2l). The densest place has 14-20 individuals per sprouts which are connected through under- sq. m. The number of saplings decreases sharply ground shoots (fallen stems originally). with the distance from the parent tree. The Large trees ( 15-20 m high) of Persea america- farthest sapling in Plot A9 was 16.7 m from the na (avocado) which were planted for the land- stem of its parent. Seed of Persea is very big mark of property borders in the past make a line (heavy) and it contains much nutrients, so it within theScalesia forest (Plot A9). There are so germinates easily and the seedling maintains itself many saplings of Persea growing around a parent under the canopy for some time. Once it es- 37 Regional Views No. I I 1997 Fig.21. Profile diagran of Plot A9 rhoring the invasion of pcnea americam (one adult hee and many sapling$ Abbr: P) in t}re Scalaia pdurculata (!tbbt.: S) forest Fig. 22. Proflle rliagram ol Miconia scrub il Plot A10. AII Miconia shnbc were dead at the tine of curvey. Keyc to abbrevlations: Ci" Cinclnna succintbraT M, Miconia robiwoniana; Ph', heridium aquilinum. tablishes in the scalesia forest, it grows up to a tall individuals of Miconia are dead. The invasion of tree shading out adjacent scalesia trees. But Cinchona is not so frequent. fortunately, there seems to be no animal which On the contrary, almost all individuals of Mic- can disperse seeds of Persea in this area, so its onia are dead due to the drought in 1994 on the spreading speed is very slow. On the way from opposite side of the slope with a small valley (Fig. Bella Vista to Media Luna, there is a big planta- 22). This side of the slope is gentle but dry tion of Persea whose height attains over 20 m. It because the soil layer is thin and evaporation must is very dark under the dense canopy and no be greater in the morning. Cinchona is frequently shrubs or herbs are found on the floor. distributed here. The concentrated death of Mic- onia is surely accelerating the invasion of cincho- (5) Miconia robinsoniana scrub na. I found many saplings of Cinchona together Miconia robinsoniana scrub features the Moist- with those of Miconia growing under the dead scrub zone which is located between Moist-forest open canopy . Pteridium aquilinum is also invad- zone (Scalesia forest) and Highland zon e (pteri- ing the scrub. It is speculated that Miconia occa- dium thicket) in Santa Cruz. Most of the Mic- sionally die all at once in especially arid years, but onia habitats were destroyed by human activities Miconia scrub could recover soon unless a com- and alien plants. A Miconia scrub, Z m high, petitive species like Cinchona prevented the covers the \M-facing slope of Media Luna densely. growth of Miconia saplings. Cinchona may take It is left in a natural condition. The slope is steep the place of Miconia here little by little, and the but moist probably because it is shaded by the Miconia scrub will disappear in the future as we mountain in the morning and it is frequently can see in Plot A5. shrouded by fog in the afternoon. Only a few 38 Competitive Relationships between Tree Species of Sco/esia and Introduced Plants (Shimizu) 2. Site B (Los Gemelos) PLOT Bl ( 1) Location Site B is located at the altitude 560-580 m in the western part of the central mountains in Santa Craz (see Fig. a). Most of the area is on a gentle slope of the windward side near the ridge, and some part is on the leeward side beyond the ridge. ０・３ □ The area is called Los Gemelos after the two DBH CLASS(cm) small craters (twins craters). A road which con- S(aliVO I■ S(dead) □ nects Baltra Airport and Puerto Ayora passes through the area. A vast Scalesia pedunculata ヽノ forest spreads in this area (Photo 3). This forest 雀】くヽ バ〓＞【】 Ｚ〓バ）“コ is frequently shrouded by fog. The twins craters and a part of the Scalesia forest are one of the important eco-tour spots in Santa Cruz. The lower border of the forest is adjacent to private “ゝ pasture lands in which small patches of Scalesia ‘ ⊃Ｚ forest are still left. Cinchona succirubra is spread- ing rapidly along the road and has been invading DBH CLASS(cm) S[コ alive l■ dead in part into the Sca lesia forest. (2) Scalesia pedunculata forest ヽＤ ′ PLOT B8 The species composition is poor, and the forest 〔 コ く structure is simple in the Scalesia forest (Plots B I ⊇ Ｑ ＞ 一 and B8), which is as the same as in the Scalesia Ｑ 乙』 υ “ forest in Site A. The canopy (Tl-layer) consists exclusively of Scalesia pedunculata. The tree 国 田 ２ height changes from 4 m to l0 m according to the つ Ｚ depth of soils. The DBH histograms show uni- 0-3 3-6 6-9 9-12 12-15 modal distribution patterns (Fig. 23). Dead trees DBH CLASS(cm) probably due to self-thinning are concentrated to SEコ ahve l■ dead thin stem classes. Stems of Scalesia trees are Fig。 23。 DBH histograms oF Scaras,α fOrest in usually straight and single (Fig. 24). These fea- Plots Bl,B6and B8。 Key to abbre宙 attons:S, tures suggest that the population is composed of Scα Jgs'α μ″ Ja如 。 “"c“ ffs. 24. ProffIe diagram of Scalrr;ia forert in Plot B8. Keys to abbreviations: Pg Ptiilium galapageium, Pv' Psychotria rufrpq, S, Scal,aia @uncalttti 7,1, Zantlnxylum fagarc. Underlined rymbob chor dead trees. 一- 39 -― Regional Views No. 11 1997 Tl:O T2:s S:x dead:r 10mX10m .S o.s a Fig. 25. Crown projection diagram of Scalesia forest in Plot 88. Keys to abbreviations: Pg, Psidium galapageium; S, Scalesi a pedunculatai Tf, Toumefortia pubescensi Zf, Zanthoxylum fagara. the same-age individuals which established all at densely. Two vines, Passiflora colinvauxii and once in the near past. Stictocardia tiliifolia, appear frequently. A young The canopy has many small gaps among tree of Cinchona succirubra, 3 m high, is also crowns (Fig. 25), so the relative light intensity on found at the edge of the gap. the floor is not so low (8.6Vo). The coverage of There is a small patch of young forest of Scale- the Shrub layer is small. It is mainly composed of sia in a private land (Plot BZ). Stumps cut at the some shrubby species such as Chiococca alba, height of about 0.5 m are scattered in the plot Psychotria rufipes, Sida rhombifolia, Tournefortia (Fig. 27). The diameter class histogram of rufosericea and Zanthoxylum fagara. The forest stumps measured at the height of 0.2 m shows floor and tree trunks are covered with moss and that a typical Scalesia forest was there before lichen. Fern species are abundant in the Herb cutting (Fig. 28). Many saplings of Scalesia,3- layer. No seedlings and saplings of Scalesia are 4 m high, are growing vigorously in the plot. found under the canopy of the Scalesia forest. Each sapling has a straight stem, and branching at the base is rare. They cover about TOVo of the (3) Regeneration of Scalesra forest plot area (Fig. 29). The relative light intensity on Plot B4 is located at the border of the Scalesia the floor is 27.6Vo. These saplings are all derived forest adjacent to a private pasture land with from seeds. No sprouts from the old stumps are Pennysetum purpureum. Several fallen trees of found. Small clumps of Pennysetum purpureum Scalesia probably caused by human impact make are scattered uniformly in the plot (probably a canopy gap (Fig. 26). Some saplings (max. 2 m planted by man) which are grazed by cows. Ac- high) of Scalesia are found in the canopy gap. cording to these features, this forest must have Ageratum conyzoides, a tall herb, invaded the gap been cut one or two years ago. 40 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) &И oγ 7へ『―――→ - -10m Ｃ ， ｉ Fig. 26. Profile diagram of Scalesia forest with a canopy gap in Plot 84. Keys to abbreviations: ■ Cinchona succirubra; Py; Psychotria rufipes; S, Scalesia pedunculata; Tf, Toumefortia rufosericeai Zanthoxylum fagara. Fie,.27. Proffle diagram of Scabia young foreet after cutting in Plot 82. Keys to abbreviations: Pqy' Pennysefrtm parpurcumi S, &alesia pdunculata. ４ ５ ０ 颯 Ｚ ８ 饉 目 ２ Fig. 28. Diameter histogram of Scalesia young peduncu' -6 6-9 9-12 12-15 15-18 forest in Plot 82. Diameter of Scalesia DIAMETER CLASS (cm) lata (Abbr.: S) was measured at the height of 0.2 ■ stump □ Sapling m. A lot of saplings and seedlings of Scalesia are saplings are less than I m high. The tallest indi- growing in an open grassland (Paspahtm, Cy- vidual is 1.45 m high. This means they germinat- pents, Sida) between the road and one of the ed within one year. Some of the small individuals twins craters (Plot B9). A path to the crater are dead because of self-thinning and drought in passes through the plot. Two small trees of part. Four saplings of Psidium guaiava are also Scalesia which are the supposed seed source of invading the plot in a clump. this plot occur in the plot (Fig. 30). Most of the -41- Reglonal Views No. 11 1997 x young tree 5mX10m ●XX x X X ● X X X● X X メ X XX . x /＼ ~ ∧ χ FfS. 29. Clown projection dirgran of Scalsia young forert after cutting in Plot 82. Keye to abbreviations: Pny, Pennysetum purpureumi S, Scalesia pedunculata. T1 :O Saplirg: p; s; S x (lm.alm3, dead 8mX10m Ｘ ▲ ▲ ▲ ▲ ▲ 】 Ｘ 静 χ Ｘ ‘ ≒ Ｘ 直 Ｘ I .li ~● / X ♂ Ｘ ノ 口 ／ 子 Ｘ “′ ● “ 」 Ａ = １ 一 ル 口 ヽ ′ 号 く ′ ― ノ 〃 く ′ お ′ 一 ロ 一 Ｉ ン 10 ノ 一 一 レ ′ ノ ′ ノ ′ Fi8. 30. Dlstribufion of Scalrrria ssDlin$ in an open plrce (Plot B9). Keyr to abbreviationr: Pru,, Pasqnlum coniugafrtmiPi,PsidiumsaCiava1,Pol,Ploy@iumdiqenamiSrJr,alaliapr/lurlr,uto&;isid,sida rlnmbijotiai SlD, Scleria ptercta. ―- 42 -― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) (4) Invasion of Cinchona succirubra are distributed patchily in the plot (Fig. 3l ). Plot B5 shows the invasion of Cinchona succi- Gaps among the clumps are densely covered with rabra in a Pteridium aquilinum thicket in a desert- Pteridium thicket, l-Zm high (Fig. 32). Even ed private land. Clumps of Cinchona,3-5 m high, the tallest tree of Cinchona is 5 m high. All trees 丁2:o S: x lomX10m 引 劇 神 ヽ 印 岸 威 川 Fig. 31. Crown Drojection diagram of Plot 85 chowing the invacion ot Cinclnna succirubru (Abbr.: Ci) in a dense Ptcri.itium aquilinum (Abbr.: Ptr) thicket. Itackg of cattle Oroken lines) rrc ranning through the plot- Fie. 32. Proflle diagram of Plot 85 shorirg the invarion of Cinchona in a dense thi*et of Pnridilzr. Keys to abbreviedonst Ci, Circhona wccirubmi Pg, hiilium galqageiumi Pfi, Ptcridium aquilinum. ―- 43 -― Regional Views No.11 1997 丁1:0 丁2:o S:x dead:● 10mX10m Fig.33. Crown projection diagran ol Scalesia forest with a Cinchana tree in Plot 86. Keys to abbrevirtions: 6, Chiuuca alba; Ci, Cinclwna succirubmi Py, hlchotria rufirc, S, Scalesia pcdunculata; Tf , ToarneJofiia rufueicca; 7,f , T,anthoxylum fagara. with a height of more than 3 m produce fruit. (Fig. 35). They produce much fruit. There are at Only three saplings less than I m high and no least 4 dead trees of Sca lesia in the T2-layer seedlings are found in the plot. So the regenera- standing just around the Cinchona trees. It is tion of Cinchona is not continuous. This place is clear that they were shaded out by the crowns of a seed source of Cinchona invasion to the adjacent Cinchona trees. A big rotten tree trunk is lying on Scalesia forest. the ground. It might have made a canopy gap Plot 86 was put in a typical Scalesia forest and Cinchona has invaded the gap successfully. A (Fig. 33), 8 m high, located about 50 m from Plot big trunk of Psidium galapageium is also lying on 85. As Plot B6 is at the leeward (north) side of the ground from which some vertical shoots grow Plot 85, a lot of wind-dispersed seeds of Cinchona upward. There are no seedlings and saplings of must be blown into the forest. Nevertheless, the either Scalesia or Cinchona in the plot. invasion of Cinchona is very rare. No seedlings and saplings of Cinchona are found under the (5) Relationships between Scalesia and other canopy of the Scalesia forest. There are, in fact, introduced plants a few young Cinchona trees growing in the forest, Several big trees of Persea americana, 15 m but they are suppressed by the canopy and none high, are found in the ^Scalesia forest (Plot B3). produce fruit (Fig. 34). The forest floor is mossy Persea has a large conical crown (Fig. 36). The and fern species are abundant in the Herb layer. crown made of horizontally spreading branches is Plot B7 shows a rare example that Cinchona so dense that it is dark under the canopy. Scalesia has succeeded in invading the Scalesia forest. trees near the Persea tree are suppressed by the Three Cinchona trees, 11 m high, put their crowns crown and some are dead. There are many above the canopy of Scalesia forest, 9 m high saplings of Persea around the parental tree (Fig. ―- 44 -一 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Fig.34. Proffle diagram of Scalasia forest with g Cinclnna tree in Plot 86. Keys to abbrevirtionc: C\ Chiococca alba; Ci, Cinclnru saccirubra; Py, Pslchotria rufipes, S, Scalrr;ia pdancuhtaT Tl, Tourncfortia rufoseica. Underlined symbols ehow dead hees. Fig.35. Protrle diagram ol Scalcsia forect in Ptot 87 showing the invasion ol Cinclntu trees. Keys to abbreviations: Ci, Cinclnna succirabm3 S, Scalesia pdunculntai Tl, Tournefortia rufoseicea. Underlined cymbols show de.d trees. 37). Most of the saplings are distributed within and white hairs underneath is making a dense the distance of 20 m from the parental tree. The bush at the sunny forest edge along the road. It height class distribution suggests that these sap- produces much edible fruit which is dispersed by lings are the same-age population (Fig. 38). birds and animals. Caesalpinia bondoc also forms Rubus sp. characterized by straight leaf veins a large dense thicket in open places. But these 45 Regional Views No. 11 1997 Fig. 36. Proftle diagram of Scolesia forest in Plot 83 showing the invasion of a Persea hee. Keys to abbreviations: P, Penea arnericana; Py, Psychotria rufipes; S, Scclesia pedunculata; Zf, Zanthoxylum fagara. 10 2.5♀ 20m プ ′ 針 た 下 ノ T1 :O T2:s S:x dead:o Sapf ing:rP Fig. 37. Crown projection diagram of Scalesia forest in Plot 83 showing the invasion of a large tree and many sapHngs of Perrea. Keys to abbreviations: P, Percea amcricana; S, Scalesia pedunculata; Zf, Zanthoxylum fagara. Fig. 38. Height histogram of Percea americana 1-2 2-3 saplings in Plot 83. HEIGHT CLASS (m) introduced species seemingly can not invade the divided geographically into two parts: Northern inside of the closed Scalesia forest. Isabela (Alcedo, Darwin and Wolf) and Southern Isabela (Sierra Negra and Cerro Azul) by a 3. Site C (Atemania) narrow strip of young lava flow named Perry ( 1) Location Isthmus. Isabela is the largest island in the archipelago. Site C is located on the south-west slope of It is composed of five main volcanoes each of Sierra Negra (peak: I49O m). There is a place which has a large caldera at the top. Isabela is called Alemania where people once colonized and ―-46 -一 Competitive Relationships between Tree Species of Scc/es ia and Introduced Plants (Shimizu) abandoned before World War II. They intro- As the Moist-forest zone is transitional to drier duced many alien plants and animals at that time. vegetation without Scalesia (Semi-arid zone) at Our camp site was set up on a gentle slope at 0o the lower elevation, I put some plots there, too. 54'18"s and 91o I l'30"w (Fig. 39). It took There is a small experimental forest of Scalesia about five hours by horse from the end of the car cordata left isolated in the agricultural area at road near the summit of Sierra Negra to the camp Santo Tom6s. It is preserved for the future seed site. The altitude of the camp site, ZZO m, belongs source of reforestation and education of local to the lower part of Moist-forest zone (scalesia people. I refer to this forest in Site C. cordata forest) originally, but almost all the area is covered with a secondary forest of psidium (2) Scalesia cordata forest guajava which was introduced by the colonists in Scalesia cordata must have made a vast forest the past. only small patches of scalesia forests on the Moist-forest zone of the Southern Isabela. (remnant forest) are scattered among the psi- As all Scalesia forests left in Site C have received dium forests. more or less direct or indirect human impacts, it This area suffered from big fires in 1985 and is difficult to imagine the original condition of the 1994. Approximately 35G4500 ha burned in Scalesia forest. However, the studies of remnant April-June, 1994 (Marquez et al. 1994), and the Scalesia forests in this area show that the struc- forest has been recovering from the fire (photo ture and the species composition of the forest are 4). I surveyed the influence of the fire on the nearly the same as those of Scalesia pedunculata vegetation in this area as a member of Japanese forest in Santa Cruz (Site A and Site B). Mission in June, 1994 (JICA 1994). So I could The canopy is dominated exclusively by Scale- study the vegetation about one year after the fire sia cordata in the typical Scalesia forest at the this time. upper elevation (Plot C10: Alt. 330 m). Stems Sierra Negra Mo■ st Dry SW SSW ヽ wind pteridir,rrl Thicket VeJ,aseo(Site D) 800m Her Grass Meadow Psidium Scrub Lava F].ow 700m W毛 Psi.dit,m Forest (closed canopy) 400m 450m ｀ ´~｀ ・ ″″ ｀ ハ爾 、 ′ 、Aユ 2ュa 、 ・ ′ ―Lower limit of Ccrd∂ 亡∂ ′ ● ヽ〈 \ 0｀ Fite c) ヽBurned in ■994｀、 ヽ ヽ 0｀ 、 Semi-arid Zone ヽ Fig. 39. Schematic presentation showing the distribution of Scalesia cordata forest and the invasion of Psidium guajava in Site C and D area, Isabela. See the text for frrrther explanations. 47 Regional Views No. 11 1997 Fig. 40. Profile diagram of Scalesia forest in Plot C10 showing the invasion of Psidium. Keys to abbreviations: Kln, Kalanchoe pinnata; Pj, Psidium guajava; S, Scclesia cordatal Tf, Toumefortia pubescens 1 Zf, Zanthoxylum fagara. 10mX10m Fig. 41. Crown projectioa dir€ran of Scalsia forest in Plot C10 showing the invasion ol hidium. Keyr to abbrevirtions: Pj, hidium guajava; S, Scalaia ardata3 Tf, Tourmefortia pufuscensT 7,f, Zanthoxylum fagara. are usually single and straight (Fig. 40). Though found in the plot. There is some amount of soil the canopy (Tl +T2layers) is nearly closed (Fig. with a thick humus layer. The forest floor is 4l), the relative light intensity is not so low moist and mossy. Kalanchoe pinnata, an escaped (15.2Vo) . No seedlings or saplings of Scalesia are horticultural plant, grew densely in the Herb 48 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) layer. Psidium guajava has established in this forest at the lower elevation (Plots C3 and C4: plot, spreading large crowns in the T2-layer. Alt. 180m). The ratio of Croton scouleri, an On the other hand, the species composition of element of the lower and drier zone, becomes the canopy is more diversified in the remnant high (Fig. 42, Fig. 43). Pisonia floribunda, Psi- T1 : O T2:a S: x dead: o Fig.42. Crown projection diagram ol Scalesia-Croton mired forest in Plot Cil showing the invasion of Psidium. Keyo to abbreviations: G, Cmton scoulori; Pt, Pinnia flaribunda;, Pi, Psidiam guqiaw; S, Scafesia ardata3 Tl, Tounefortfu pubescens; Zl, Tnnthoxylum fagam. Fig. 43. Proffle diagram of Scalaia-Croton nired forest in Plot C3 ehoring the invesion of Psidium. Keyz to abbreviationsz Cr, Ctobn scouler\ W. Pisonia fl.oribunila; P!, hidiam guajava3 S, Soolesia corfutaS Zf, Zantlnxylum fagaru. 49 Regional Views No. 11 1997 な い 『を う∩】 ≧面 Ｚ一 Ｌ Ｏ∝蜃四 Σ ⊃ Ｚ 6-9 ＜ 9-12 12-15 DBH CLASS ｃｍ □ ■硼 圏 Cr others ● ∽ ｄ 己 冒 ２ 【 ｂ 蚤 冒ヲ PLOT C10 ．９‐２ 0-3 6-9 ＜ ＞ 12-15 15-18 DBH CLASS ｃｍ Fig. 44. DBH histograms of Plots C4 and C10. □■ 目硼 Keys abbreviations: Pj to Cr, Croton scoubrti Pj, others Psidium guajava; S, Scclesia cordata. Fig. 45. ProfiIe diagram of the Scalesia experimental forest in Plot C16 showing the invasion of Psidium. Keys to abbreviations: Pg, Psidium galapageium; Pi, Psidium guajava; S, Scalesia cordatal Tf, Tournefortia pubescens; Zf, Zanthoxylum fagara. d ium gal ap ageiu m, Z an thoxy lu m fagara and Tour- is invading the forest to some extent. It spreads nefortia pubescens ate common in the forest. The branches forming a large crown in the T2-layer. soil layer is very thin. Basal lava rocks are Young trees and saplings of Psidium are also exposed here and there. The surface of the rocky found under the canopy in contrast to Scalesia. floor is thinly covered with fallen leaves, moss and The experimental forest (Plot C16) at Corazon lichen. The canopy is loose and the relative light verde (0" 5 r'27"s, 9t"01'35 "w, Alt. 310 m), intensity on the floor is high (33.lVo in Plot Ca). Santo Tom6s, is the only forest of Scalesia cordata Nevertheless, no seedlings and saplings of Sca lesia left on the moist south (windward) slope of Sierra are found in the forest (Fig. 4). The Herb layer Negra near the village (Photo 5). The place (42 is poor in quality and quantity. Psidium guajava m X 50 m) is enclosed with a fence to keep live- -50- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) stock out. This forest seems to have the original place, it makes a pure forest (Plots Cl and C9). structure and species composition of Scalesia for- The canopy (TlJayer) and T2-layer are exclu- est, though some Scalesia individuals were plant- sively composed of Psidium (Fig. 47). Crowns ed in the past and the Shrub and Herb-layers are usually wider and thicker than those of Scale- are controled by man (Fig. 45). The total of 168 sia and they overlap with each other (Fig. 48). matured individuals of Scalesia are numbered, But the relative light intensity on the floor is not and the population dynamics has been observed so low in Plot Cl (l3.OVo). Most of the canopy by the Isabela Branch of CDRS. trees have a multi-stemed growth form. The The canopy is composed exclusively of S. cor- average number of stems per canopy tree is 2.5 in data. The DBH histogram shows a clear mode at Plot Cl and 2.9 in Plot C9. Most of the stems are the class 6-9 cm (Fi g. 46). Dead trees are con- thin, with DBH less than 6 cm in both plots (Fig. centrated to thin individuals with the DBH less 49). Many T}-layer individuals (43.3Vo) of Psr- than 6 cm. I could find some Scalesia saplings dium have damaged top of stems in Plot C9. growing in a large canopy gap outside the plot These features show that the forests are not so area. This forest is surrounded by Psidium gua- old. As I found thick dead (rotten) stems left at java forest and Pteridium aquilinum thicket. the center of the present stumps in Plot C 1, this Alien species have been removed from the exper- forest might have burned in 1985 and recovered imental forest. This forest is also used as teaching by sprouts again. materials for local school children. CDRS has a It is characteristic that saplings of Pstdium exist plan to enlarge the enclosed area (to buy the under the canopy. The Shrub-layer of the forest surrounding area) and to do experimental studies is very poor. The soil is very thin but the ground on the regeneration of S. cordata forest. made of exposed lava is mostly covered thinly with moss and fallen leaves. The Herb-layer is (3) Psidium guajava forest dominated by Ctenitis sloanei in the moist habitat Once Psidium guajava has established in a of Plot Cl, while the coverage of the Herb-layer is 1 3-6 6-9 9-12 12-15 15-18 DBH CLASS (cm) Fig. 4,6. DBH histogram of Plot C16. Keys to □陶 guaiavai Scalesia lalivO ■ S (dead) abbreviations: Pj, Psi.dium S' 躍 Zf cordata; Zf, Zanthoxylum fagara. 5m 「 FiS. 47. Proffle rllagnm ot hidium dominrnt forect in PIot Cl. Keys to abbreviations: Cto., Ct nitis sloartalii Pi, Itlidiun guojava. -51- Regional Views No. 11 1997 Tl:O T2:@ S: x dead: e 10mX10m Fig.48. Crown projection diagram of Psidium doninmt foreet in Plot Cl. Keyr to abbreviatione: Pj, hidium guajavai Tf, Tournefonia pubacens. 仏 ） PLOT Cl 司∽ く ⊃ ６ 躍 ‘ ６ ２ 日 』 〇 “ 国 国 Σ ５ Ｚ 闘 6-9 9-12 12-15, DBH CLASS (cm) □ alive l■ dead Φ ∽ ゼ 己 冒 ２ 】 ｂ 蚤 PLOT C9 曽２ ６ ９ j“ ． 12-15 Fig。 419. DBH hbtog,ams of Psjご g“a」ava in 田 」 Ａ Ｓ Ｓ Plo撻 Cl and C9。 “ 一- 52 -― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) low in the drier habitat of Plot C9. Seedlings of rnefortia pubescens, T. rufosericea, Cordia leucost- Psidium are also found on the floor. The seed- achys and Zanthoxylum fagara are common in lings have a thick and straight root under the both the Semi-arid and the Sca lesia forests. Zan- ground (Fig. 50). New shoots frequently appear thoxylum is especially dominant in the Shrub- from the base when the top of the old shoot is layer of this forest. Psidium guajava is invading damaged or the main stem falls down. Seedlings here, too, but the frequency is low compared with and saplings of Psidium with shade-tolerant abil- upper elevations. Most of the herbaceous species ity can survive for some years under the canopy. are also common to those of Scalesia forest, but the ratio of fern species is lower because of drier (4) Semi-arid (Transitional) zone condition. Scalesia cordata disappears at the altitude plot c6 (0'55'25"S, glo l1'33"\M, Alt. 195 m) around 160 m en route from the remnant forest is located between the remnant Scalesro forest and (Plots C3 and C4) down toward Mt. Soritario. the Semi-arid forest (Plot C5) . Pisonia flo- There is a natural forest which belongs to the ribunda, Psidium guajava, Acnistus ellipticus and Semi-arid (Transitional) zone at the altitude 150 Zanthoxylum fagara make a thick closed canopy m (Plot C5). This forest has not burned before. (Fig. 52). Psidium guajava has become a member A big tree of Pisonia floribunda makes a large of this forest completely. The largest tree of crown (7-8 m high) in the plot (Fig. 51). The Psidium is 7 m high and 9.9 cm DBH. Zanthox- main trunk is lying from which several vertical ylum is frequent in the T}-layer. It is relatively stems elongate upward. This kind of growth form dark under the closed canopy. The Shrub-layer is is common to Pisonia trees in this region. It was nearly vacant. No Sca lesia trees are found in and shedding most leaves at the time of the survey, so around the plot. The floor is relatively mossy. it is bright in the forest. Eight species form the Ctenitis sloanei which indicates the moist and dense coverage of the T2-layer, 4 m high. Pisonia stable condition of the habitat is abundant in the floribunda and Psidium galapageium are charac- Herb-layer. teristic of the Semi-arid zone in this region. Tou- 25cm Fig. 50. Growth forms of a seedling and saplings of Psidium guajava. ―- 53 -一 Regional Views No。 11 1997 (5) Influence of the fires and regeneration of tion (altitude, aspect), amount of fuels (dried Scalesia organic matters) and wind direction, so burnt and This area was seriously damaged by the big unburned parts make mosaic distribution in this fires in 1985 and 1994 (There might have been area. Only a small part of the area was burned several non-documented fires in the past). The completely to ashes. The burnt area was still dark degree of damage is variable according to the brownish one year after the L994 fire, when I various conditions such as vegetation types, loca- looked down on it from a high place. Main stems -8m み ″ '`(11:)〕 4m―― ガ Fig. Proffle diagram 51. of eeni-.rid mixed forest in Plot C5. Keyc to ebbreviationg: Pf, Pisonia floribunda3 co, cordia lcuaphlyctls; Pg, hidium gahpageium, p!, hidium guajaw; rJr, urea caracasana; zr, Tantlnxylun fagara. Fig" 52. Proffle diagram of remi-erid mixed forest tn Plot C6 with the invagion ol 73idiam. Keyr to abbreviations: Ac, Acnistus ellipticusi h, Ctenitis storlneii Pf, Pisonia floribanda; P!, Psidium guajava; Tt, Toarncfortia pahcensi ft, Tantlnxylun Jagam, -54- Competitive Relationships between Tree Species of Scclesia and Introduced Plants (Shimizu) of Psidium guajava were dead, but still standing tion pattern of DBH class histogram for dead with even small branches on the dead crowns stems in Plot C2 is similar to that of living stems (Plots C2 and C8). in Plot Cl (Fig. 53), there must have been a Plot CZ is located close to Plot C 1 (the un- Psidium guajava forest similar to Plot Cl before it burned Psidium guajava forest). As the distribu- burned in Plot C2. Only a few trees have survived the fire. Though main stems of Psidium are dead ＞ completely, many new shoots are sprouting from 一 ヨ the base of burnt trees, not from the dead trunks 昌 買２ (Fig. 54). The number of new shoots per individ- ual is between 0 and 6 (1.6 in average) (Fig. 55). ８ 蟹 冒 If it is calculated excluding the individuals with no shoots, the average is 2.4 shoots per individual. ヲ All new shoots are less than 2 m high at the time of survey (Fig. 56). DBH CLASS(cm) There is a large tree of Trema micrantha in the ■ dead 国 Pj ■Tr plot which burned to death. Many saplings of Trema are scattered around the parent tree (Fig. 57). The highest Trema sapling was 2.2 m. These ・Ｄ・ saplings must have germinated from seeds after ∽ コ く the canopy became open by the fire. There are ⊃ ∩【 ＞一 ∩Ｚ ∵ some saplings of Psidium guajava, too. The height of saplings from seeds is not so different 六） ∝ ﹈ 日Σ from that of the new shoots from burnt trees (Fig. 56). The humus layer burned so completely ⊃Ｚ that basal lava rock is exposed on the floor of the 0-3 3-6 6-9 9-12 12-15 forest. The HerbJayer is dominated by a light Pj■l dead demanding fern, Pteridium aquilinuffi, in Plot C2 Fig. 53. DBH histograms of burnt Psidium instead of Ctenitis sloanei in Plot C 1. dominant forests in Plots C2 and C8. Keys to Plot C8 shows the Psidium guajava forest abbreviation$ Pj, Psidium guajavai Tr, Trema which burned severely (Fig. 58). No canopy micrantha. trees have survived. The present situation is very FiS. 54. hofle diagrrn of bunt hidium dominant forest ir Plot C2. Keyr to abbreviadons: Pl, Ptidium guqiavai Pfr, Pteridium a4uilinam; T4 Ttuna micmncha. Underlined rynbolg ghov dead treer. ―- 55 -― Regional Vie■ ァs No。 11 1997 (a) PLOT C2 理16 目揚 86妻 2 3 4 :| 0。 5-1 1-1.5 1.5-2 NO. OF SH00TS HEIGHT CLASS(m) 圏 shoot ヽノ (b) め コく⊃∩一 ＞】 ∩ＺＦ【】縣用でこ :[ 1 ⊃ Ｚ 言 0 1 2 3 4 5 6 7 C「0.5 0.5-1 1-1.5 1.5-2 2-2.5 HEIGHT CLASS(0 ■ sh∞ t tt sapling Fig.55。 Histograms of the number of new shoots per bllrnt fな jご j“ g“ aJavα hdi▼idual in Fig。 56. H[eight histograms of new shoots and Plo"C2and C8。 “ saplintt of Psiご J“ ″ g“a」aッα in Plo撻 C2and C8。 T1 :O T2:o S: x dead: oPj Sapf ing: nTr 10mX10m ● ●. ロ ロ ● ロ ロ . :ロ ロロ |・ ● ● ● ロロ . _. |ロ ロ ° ロ ロ ロ ロ ● ロ ロ ●. ● ● ロ 口 ロ: ● ロ ロ ● ロ ロ ロ ロ ロ ● ロ ●ロ 口 ロ ０ ロ X X ・ ロ X χ 出 ロ . Fi8. 57. Dirtribution of hidium guqjava (Abbr.: Pj) and new stDtinEr ol Ttema micmntlu (Abbr.: Tr) after the fre in the burnt.Bidinz flsninrnt forest in Plot C2. ―- 56-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimitu) ら 号 一 一 FiS. 58. Proffle diagren of burnt.kidizm dominrt forecl Keyc to abbrevirrtions: Pi, Psidium guajava3 Pfu, Ptzridium aquilinum. Undertned symbolo shor dead hees. burned +le-- unburned Fig. 59. Proflle diagram of transitional part betveen burned and unburned forestr choring denre growth of Scalesia saplinss in Plot C7. Keys to abbreviationr:, Pi, hidium guajava3 Pb' Pteidium aqailinumi S, Scalqia cordata; Tr, Tlvma mbrantlu. Underlined symbolr show derd hees. similar to that of Plot C2, though there are no Plot C7 is located at the border between burnt Trema saplings in Plot C8. New shoots are (Plot C8) and unburned (Plot C9) area. A sprouting from the base of the dead stems. The matured tree of Scalesra is left at the periphery of number of shoots per individual falls between 0 the unburned area, which might be the seed and 7 (3.0 in average) (Fig. 55). The dense source of the Scalesia saplings in the plot (Fig. coverage of Pteridium aquilinilffi, 1-1.5 m high, 59). A tall tree of Trema is also standing just has established in the Herb-layer. This coverage outside of the plot. Almost all trees of Psidium of Pteridium seems to prevent seedlings of tree guajava died in the fire, but new shoots are sprout- species from re-establishing. Many of the new ing from the base of dead trunks as seen in Plots shoots of Psidium, l-2 m high, have already been C2 and C8. The number of stems per individual above the thicket of Pteridium. Rugged basal is between 0 and 7 (2.3 in average) (Fig. 60). lava is exposed on the floor. The height of the Psidium shoots is less than 2 m Saplings of Scalesia cordata were found only at (Fie. 61a). the limited places where some adult Scalesia trees On the other hand, saplings of Sca lesia originat- have survived the fire (Plots C7, Cl1, and C14). ed from seeds have been growing very fast in Plot s7 Regional Views No. 11 1997 ａ ＞ ∽ ヨ PLOT C7 ８ 買 ２８ 巨 国ヲ □S tt Pj ・Ｄ ） 〔 コマづ ２ ０ こで‘∩Ｚ Fig. 60. Histograms of the number of nerr １ ５ (Abbr.: shoots from a burnt Psidium guajava Pj) ∵ ‐ ０５ 六） individual and the number of shoots per Scc lesia ∝ 国四≧⊃ cordata (Abbr: S) sapling in Plot C7. Ｚ ０ 0-0.5 0。 5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 HEIGHT CLASS (m) C7. The histogram of sapling height shows a □ S mode between 2.5 m and 3 m (Fie. 61a). The ｃ＞ highest individual was 3.5 m. This means Scalesia コ has advantage over stage an Psidium in the early 昌 of regeneration after fires. Saplings of Scalesia ≧２ have usually one stem per individual, and multi- ８螢 stemmed growth form is not so frequent (Fig. 60). Saplings of Scalesia are distributed around 冨 the supposed parent tree. The density of saplings ｚ 0-0。 5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 is 1.4 individuals per sq. m. at the center of the HEIGHT CLASS (m) distribution. Small crowns of the saplings make a □S continuous canopy together (Fig. 62). But the ｄ number of saplings decreases sharply with the 電 ｇ distance from the parent tree. Only one sapling of Ｄ Ａ Ｚ８ “ 国 Scalesia is dead, so self-thinning will happen from now. Saplings of Trema micrantha are sparsely distributed in the plot (Fig. 62). Pteridium aqui- ≧ ｚ linum thrives in an open space of the plot, but it can not grow under the canopy of Scalesia 0-0。 5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 saplings. HEIGHT CLASS (m) □S Plot Cll is a belt-transect which was put through the border between burnt and unburned Fig. 61. Heig[t histograms of new saplingg after places. It is a part of the remnant Scalesia forest the fire in Plots C7, Cll, Cl2 and C14. Keys to (Plots C3 and C4). According to the present abbreviations: Pj, Psidium guajavai S, Scalesia situation, the plot area is divided into three parts; cordata; Tr, Trcma micrantlta. Part A: burnt, Part B: transitional and Part C: unburned (Fig. 63, Fig. 64). The fire came to Part B in this place. In Part A and Part B, most m. Most of the saplings have single stem with a of the canopy trees (Psidium guajava and Scalesia cylindrical crown above 1.5 m. Some saplings less cordata) were burnt, and only a few have survi- than 0.8 m high are dead, probably because of ved the fire (Table 2). As Pteridium aquilinum self- thinning. None produces flowers. There are covers the ground densely, saplings of Scalesia are some saplings of Zanthozylum fagara, Tournefor- rare (8 individuals) in Part A. tia spp., Psidium galapageium and Chiococca alba. On the contrary, many saplings ( 145 individ- Malvastram coromandelianum is growing fre- uals) of Scalesra form a dense thicket in Part B. quently in the Herb-layer in Part B instead of The height distribution has a mode between 2 m Pteridium aquilinum in Part A. On the other and 2.5 m (Fig. 61b). The maximum hieght is 3.1 hand, canopy trees of Part C are all alive except a 一- 58 -― Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) T1 :O T2:s S:x dead:opj Sapling: aS,uTr 10mX10m 三Lノ tFノ ・ ｀ 湾 ♂ ム .C(ダ 1 ′ ヽ ● 口 ′ ― ～ ロ ● 〜 ′ ロ X ● ●. ロ｀ ・ て 式 ． ● ・ △ ． イ 「 人 υ ． （ ↓、 ・ Fig.62。 Dお of burnt trees of Psidium guaiava (Abbr.: Pj), and new saplings of Scalesia cordata (Abbr.:S)and "ibuttonTramα micrantha (Abbr.: Tr) in Plot C7. 20m 10 ・ 雪軌 2.5♀ ° ４ 1 ｀ ぎ ｀ △ 叫 Ｓ △ 1ム く轟17 ぞ ム “ 到 χ ●号 × 、 0町 ＼ ル1▲ｊ や ヽ ■ ヽ ■ ｒ ツ Ｆ 鳳 ” ヽ ´ 摯 “ ― ▲ ム ４ デ 境 ― ｒ ヽ ・ ３ Ｆ れ こ0)ξ ヽ 「 サ ／ 昭 ・ Ｆ ／ ． ／ ノ .Iら ‐ ‘ η ／ Ｆ ′ ん ● 子 ｆ 一 2。 5 丁1:o T2:● 20 Fig.63. Crown projection diagran of transition l pert between buned and unburned forects chowing distribution ol Scabia gaplingr in Plot C11. Keye to abbrevhtions: P!, Esidium Pqiava; Ptrl Ptefidium aquilinumi, S, Scafeeia cordabiTf, Tounulortia pabrrirrlnsi Tl, Tnntlnxylum fagam. 一- 59 -― Regio■ al Vie■アs No. 11 1997 Port pqrt A----+l- B----rl€-- port C burned +le- unburned Fig. 64. Proffle diagran of transitional part between bumed and unburned forectr rhowing denre growth of Scalrsia caplings in Plot C11. Keys to abbreviations: Pj, hidium guajaw; Ptr, pbridium aquilinumT S, Scalesia cordata. Underlined symbols show derd hees. Table 2. species compooition in burned, hansitional and unbur:ned parts in plot cll Part A (burned) Part B (transitional) Part C (unburned) Species Name No BA No BA No BA T1-layer Scalesia cordata 1 61 574 Psidium guajava 2 59 99 Zanthoxylum fagara 62 T2-layer Scalesia cordata (141) (11) (393) Psidium galapageium (1) (3) Psidium guajava 1(7) 7 (37) 3 80 Tournefortia pub esc ens 2 11 Zanthoxylum fagara (1) (3) 2(1) 29(47) S-layer Chiococca alba 2 Psidium galapageium 1 4 Psidium guajava 6 Scalesia cordata 155 Tournefortia pubescens 3 7 Trema micrantha 1 Zanthoxylum fagara 7 H-layer Abutilon depauperatum 2 Asplenium formosum 1 Centella asiatica 2 Commerina diffusa Conyza bonariense Ctenitis sloanei 1 Doryopteris pedata Hyptis mutabilis M alv astrum conomande lianum 4 Oxalis cornicula Paspalum conjugatum 1 Polypodium dispersum Pteridium aquilinum 1 Sida rhombifolia 2 vine sp. 3 Numerals show the number of individuals (No) and bas al arca (BA: cmt) in Tl, T2 and S-layers, and relative dominance value ( l-4) in H-layer. Dead individuals are shown in parentheses. ―- 60 -― Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) tree of Zanthoxylum. No saplings of Scalesia are I found a small patch of burnt area (about 25O found under the canopy of the forest in Part C, sq. m) spotted inside the unburned forest in the even though the place is adjacent to Part B. remnant forest area neighboring to Plot C3 and Ctenitis sloanei is the most dominant fern in Part Plot C4. I put a belt-transect through the patch C. (Plot Clz). Canopy trees of Scalesia cordata (9 o plot cl4 (o" 52'29"s, g l I 2' 53''W) is located individuals), Psidium guajava (3 individuals) and near another remnant Scalesia forest (Plot C10). Zanthoxylum fagara (2 individuals) burned, A belt-transect was laid through the border be- making alarge canopy gap in the forest (Fig. 66). tween burnt and unburned places. The general Scalesia saplings make a dense coverage in the gap situation is common to that of Plot Cl I (Fig. 65). (Fig. 67), The density was 3.0 individuals per sq. The transect area was a Scalesia-Psidium mixed m in the densest part. The height class distribu- forest before the fire. It can be now divided into tion has a mode between 2.5 m and 3 m (Fig. 61 three parts: burnt, transitional and unburned. c). The maximum individual attains to 3.6 m. There are some matured Sca lesia trees left in the Saplings of Trema micrantha, Croton scouleri, and unburned part. Scalesra saplings are found in the Psidium guajava are also found in the Eap, though transitional part. Most of the saplings have a their density is very low. Pteridium aquilinum height of 1 .5-2 m (Fig. 61d). The tallest one is invaded the gap and made a small thicket, 1.5- 2.3 m high. Calanchoe pinnata makes a dense 2 m high. coverage, 1-1.5 m high, in the burnt and the Plot C 13 (belt-transect) was put to include transitional parts, so Scalesla saplings and Calan- burnt and unburned forests with a fire-break belt choe are in competitive relation here. between them in the Semi-arid zone near Plot C5 T1 : O T2:o S: x dead: o Sapl ing: a (S) 眺 5 l5m ム ∴ ５ ｒａ ムム burned unburned Fig.65. Crown projection dirgram of transitional Dart between burned and unburaed pbcec rhowing distribution of Scalaia caplings in Plot C14. Keyr to abbreviationg: l(rn, Kalanclne pinnata; P!, Psidium guqjava; P?c, Pteridium aquilinumi S, Scctracic cordata; Zf, Zanthoxylam fagara. - T1 :O T2:O S: x dead: o Sapling: a (S) ハ バ ▲ ▲ ▲ burned Fig. 66. Distribution of scalesia saplings in a forest gap Ournt part) in Plot Cl2. Keys to abbreviations: Cr, croton scoulerii Pg, Psidium galapageium; pj, psidium guajava; Ptr, Pteridium aquilinum; S, Scalesia cordatal Tr, Trema micrantha; Zf, Zanthoxylum fagara. 6t Regional Views No. 11 1997 -5m burned Fig. 67. Profile diagram of Plot 12 showing dense growth of Scalesia saplings in a canopy gap (burnt part). Keys to abbreviations: Pj, Psidium guajavai Ptr, Pteridium aquilinum; S, Scalesia cordata; Zf, Zanthoxylum fagara. Underlined symbols show dead trees. % fire-break belt t{ Pi 20m 20 burned FIg.6S. Proflle dirgram of transidonrl part betreen buned and unbutled seni-rrid forects in Plot C13 with a flre.breek belt at the center. Keys to abbreviafions: Pl, Pisonia floribunth; Pg, hidium galnpageiumi Pj, Psidium guojava; P&', Prtoridium aquilinum', Tf, Toarmefortia pubacensi Zf, Tantlnrylam fagara. Underlined synbolc shov d€rd trecs. (Fig. 68). The unburned forest consists of small There is no Scalesia cordata. The forest floor is trees of Psidium galapageium, Psidium guaiava, mossy and has several fern species. On the con- Tournefortia pubescens, T. ntfosericea and Zan- trary, the burnt area which burned in 1985 is thozylum fagara. Pisonia floribunda is sparsely covered with a dense thicket of Pteridium aqui' distributed making a large crown in the forest. linum. Only a few dead trees of Psidium galapa- 62 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) geium, P. guajava and Tournefortia pubescens ate quently distributed. standing in this area. I saw tall dead trees of Plot C15 includes four line-transects (Line 1- Pisonia floribunda and Trema micrantha standing 4) in the fire-break belt at Alemania which was here and there in this area (not included in the built in 1994 (Fig. 69). Fire fighters cut a forest belt-transect). It is probably because this place about l0 m wide and removed roots and rocks was severely burnt (most trees became ash) and (maybe buried seeds, too) from the surface by regeneration has been prevented by the dense tractor. We (Japanese Mission) used this "road" thicket of Pteridium. Basal lava is exposed in when we came here just after the fire in June, some part of the burnt area. The fire-break belt, 1994. There was no coverage of plants in the belt 4 m wide, was built to prevent the fire from atthat time (Photo 6). The present condition is spreading outward in 1985. It was repaired at the about one year after the belt was abandoned. The time of the 1994 fire. Saplings ofPsldium guajava vegetation which recovered in the belt is different are growing in open places of the belt. Malvast- from place to place (Table 3). Tall herb and rum colomanderianum and Cassia tora are fre- grasses, 1.5 m high, such as Paspalum conjuga- Q?中 彿け Fig. 69. One-year recover of vegetation on bare grounds of the fire-break belt in Plot C15. Keys to abbreviations: fpo, Ipomoea alba; Pj, Psidium guajava; S, Scalesia cordata; Tf, Tournefortia pubescens; Zf, Zanthoxylum fagara. 63 Regional Views No. 11 1997 Table 3. Relative abundance (1-,4) of plants in the fire-break belt (Plot C15) No. of line transects Species name No .l No. 2 No. 3 No4 ( 1) Herb & grasses Abutilon depauperatum Bidens pilosa Cassia tora Centella asiatica Commerina diffusa Ctenitis sloanei Cyperus sp. Desmodium canum Diodia radula Heliotropium angiospermae Hyptis mutabilis Ipomoea alba I Malvastrum colomanderianum 4 Mecardonia dianthea 2 Oxalis corniculata 2 Paspalum conjugatum 3 Salvia occidentalis Sida rhombifolia Stachytarpheta cayennensis Synedrella nodiflora (2) Seedlings & saplings Psidium guajava Scalesia cordata Tournefortia pub e sc en s tttm, Sida rhombifolia and Mecardonia dianthea saplings occur is very narrow for the total area of cover the whole ground in a flat place with thick the fire-break belt. The saplings ate making a soils (Line 3). Ipomoea alba covers exposed dense thicket, 2.5 m high in average. No other rocks and forest edges making a fringe vegetation. trees or herbs are comparable to the rapid growth On the contrary, the height and the amount of of Scalesia within one year. Saplings of Psidium herb and grasses are less in a thin soiled place on guajava are only 0.4 m in Line 4 and 0.75 m in a ridge (Line 2), though the species composition Line 1 in maximum height. The distribution of is nearly the same as the moist place. Seedlings of Psidium seedlings is concentrated and the density Psidium guajava (max. 22 cm high) are found in is partly high (17-29 per O.25 sq. m), probably open parts of the belt. because the seeds were dispersed by feral animals Saplings of Scalesia cordata are found only if (donkeys and pigs). I found a dropping of feral adult Scalesia trees exist near the fire-break belt donkey which included many seeds of Psidium in (Line I and Line 4). The area where Scalesia the fire-break belt just after the fire. As the 64 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) surface soil was removed at the construction of class shows a peak between 6 cm and 9 cm, but the belt, these saplings must have originated from the dispersion is large (Fig. 72). The largest seeds which were dispersed after the fire (not diameter measured atO.2 m high is 15.1 cm, while derived from buried seeds). the smallest was 1.7 cm in the plot. I also found some Scalesia saplings within the plot whose 4. Site D (Velasco) height is 0.5-2 m. This means that the population ( 1) Location has a variety of individuals in different develop- Site D is located on the south-west slope of mental stages. The Shrub-layer is very poor sierra Negra. It is in a transitional zone between (open). The height of herb and grasses are not so moist windward (south) side and dry leeward tall (0.3 m high in average). So the plot area (north) side of Sierra Negra (see Fig. 39). So the looks like a well-kept garden. The scarcity of general habitat condition is drier than that of site shrubs and herbs may owe partly to grazing by C. A wide range of Scalesia cordata forest feral animals (mainly donkeys). (about. 0.5 km X 0.5 km; SFI) exists in a natural Plot Dl is situated on a mound of exposed lava condition at the altitude between 730 m and 900 (Fig. 73). The existence of Opuntia insularis, m. Our camp site was put near the upper edge of Bursera graveolens, and Gossypium barbadense the forest (0" 50'33"5, 91' 1l '29"w, Alt. 790 m). which usually appear in the Arid zone of the The forest changes to a croton scoulerf dominant lowest elevation shows the aridness of this habi- forest at the altitude around 73o m, thou gh scale- tat. Cordia leucophlyctis, Tournefortia pubescens sia trees are sparsely distributed in the forest up to and Zanthoxylum fagara take a multi-stemmed about 400 m in altitude. Dry-type vegetation growth form, making a round crown. Especially, (comparable to Arid and Semi-arid zones) covers Zanthoxylum has a wide procumbent form on the the vast lower elevation. On the other hand, exposed lava. There is little soil and no moss above the upper limit of the Scalesia forest app- coverage on the ground. Moss and lichen on the ears a narrow strip of "subalpine" scrub and a trunks are also scarce. wide range of "alpine" meadow. They can be On the other hand, Plot D3 is located on a included in Moist-scrub and Highland zones in gentle slope with a thin soil layer. Canopy trees general classification, respectively. of scalesia cordata, Bursera glaveolens and rourne- There is a large lava flow which borders the fortia pubescens are only sparsely distributed in west edge of this area. A small crater is located at the plot. ,I6,,w). Many shrubs of Danviniothamnus tenui- the altitude of 700 m (0o 50'40" S, 91o l1 folius and Baccharis gnidiifolia both of which are several lava flows running vertically from high to endemic Compositae species grow in open canopy low elevations make hilly landscape in this area. gaps (Fig. 74). Some of them make a large There are some ditches (about l0 m wide, 5 m tussock which is composed of many thin stems deep) which were made of fluent lava flows in (2f50 stems per individual) (Fig. 75). Scalesia small valleys. Two narrow vertical belts of scale- saplings and young trees are also found in the sia remnant forests (SFII and SFIII) are left plot. Herbs are almost the same in the three plots along depressions located to the south of the first (Plots Dl, D3, and D10). Acalypha partula, forest: sFI (see Fig. 39). They are isolated from Synedrella nodiflora, Blainvillea dichotoma and psidium each other by grass and herb meadows. Anthephora hermaphrodita are frequently dis- guajava has been invading this area from the tributed in these plots. south, though the density is still low. A parasitic plant, Phoradendron henslovii (Photo 7), is frequently found on branches of (2) Scalesia cordata forest scalesia trees in Plots Dl and D3. As several Because of the dry habitat, high elevation (cool scalesia trees with many individuals of Phoraden- temperature) and thin immature soil, the tree dron on their crowns are nearly dead, this para- height is low (5 m high) and the canopy is not sitic plant may cause the death of some trees of closed in the sca lesia forest near the camp site scalesia. Larvae and adults of a kind of beetle (Plots Dl, D3, and D10). The canopy is exclu- (5 cm long) are also found frequently in dead sively plot dominated by scalesia cordata in D10 trunks of Scalesia in this forest (photo 8). (Fig. 70, Fig . 7l). The crowns are usually small, According to Mr. Tupiza, this beetle has been and most of them have damaged branches. All found only in scalesia cordata and sapindus sap- canopy trees of scalesra were bearing seeds at the onaria trees in Isabela. time of this survey. The histogram of diameter ―- 65 -一 Regional Views No。 11 1997 T1 :O T2.e S: x dead: o 1 0mX10m Fig. 70. Crown projection diagren ol &;allr;ia fored in Plot D10. Keys to abbreviationc: Dw, Darwiniothamn $ trlnaifoliuq, P!, Psidium gudava; S' Scalesia cordab. Ffg. 71. Proflle dtagran of &jalff,fu forest in Plot D10. Keys to abbrevietions: Dv, Darwiniotlumnus tenuifoliusi Op, Opantia ircul.aris, P!, hidium guqiavai S, Scatresia cotdtta. ∽ PLOT D10 司 く ⊃ ∩Σ∩ Ｚ】 」 ｏ“国 ｍ Σ⊃Ｚ 3-6 6-9 9-12 12-15 15-18 Fig.72. Diameter histogram of Scalesia cordata DIAMETER CLASS (cm) in Ptot D10. Diameter was measured at the □ alive l■ dead height of 0.2 m. ―- 66 -一 Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) Fig. 73. Proffle diagram ofScalcda forest in Plot Dl. Keyc to abbreviationr: Co, Cotdfu leunphlyctis; Op, Opuntia ircularisl Pi, f3itlium guajava3 S, Scclesic anhtai TI, Tournelortia pubwensi ZI, Zantlnxylum fagam. 10mX10m Fig. 74. Crown projection diagram ol Scalsia forest ir Plot D3. Keyc to abbreviations: Bls,, Boccluris gnidiifolial C-h, Chiococca alba, G, Crobn scoulrlri; Dv, Darviniothamnas lancifoliusi Pi, hidium guoiavai S, Scclcria cordatt; Tf, Tourmelortia pubacensT Zf, Zanthoxflum fagara. Ftg. 75. Proflle diagrem of Scalsia forect in Ptot D3. Xeyr to abbreviafions: R , Baccrlaris gaidiifolia; Dw' Darwiniathamnus hncilolius; P!, Psidium gaajavai S, ScaLasic corilab, Tf' Tourtufortia Pufuaens. 67 Regional Views No。 11 1997 (3) Gap regeneration of Scalesra forest remnant Scalesla forest: SFIII. A narrow belt of I found saplings of Scalesia with various tree exposed lava runs through the plot. There is a big heights growing in a canopy gap around a large Scalesia tree (5 - high, 20.0 cm DBH) in the matured tree (Plots D5 and Dlz). Plot D5 (0" center of the plot and many saplings and young 50'57" S, 9l" 12'I9''W) was put in a mixed forest trees surround the parent tree (Fig. 78). Scalesia with Croton scouleri, Scalesia cordata and Psidium saplings and young trees have diversified tree guajava at the altitude of 550m (Fig. 76). All height (0.8 m-4m) and DBH (2.1cm-8.1cm), canopy trees are thin in DBH (less than 8 cm) but the height class histogram shows a clear uni- except a large Scalesia tree with the height of 8 m modal distribution (Fig. 79). I could not find any and DBH 18.1 cm (Fig.77). (I found the largest seedlings of Scalesia here, either. Some saplings Scalesia tree in Site D near Plot D5: 7 m high and more than 2 m high have already produced 29.4 cm DBH). It is characteristic that two flowers. Darwiniothamnus lancifolizs is dominant thirds of Croton trees in the plot are dead, though Shrub layer making large patches of the cause is not known. Saplings of Scalesia have :TJ|1. a variety of stem height (1.5 m-5 m) and DBH (1.0 cm-7.8 cm). But no seedlings of Scalesia are (4) Invasion of Psidium guajava found. It is not sure whether they invaded the The invasion of Psidium guajava has been com- gap gradually or all at once. Some saplings of pleted on the moist windward (south) slope of Psidium guajava are invading the gap, increasing Sierra Negra (see FiS. 39). On the other hand, their dominance in the plot. Psidium is invading rapidly into drier area on the Plot Dl2 is located on a thin-soiled ridge in the leeward slope of Sierra Negra. As the canopy of Fig. 76. Profile diagram of Plot D5 showing the regeneration of Scalesia around a parent hee. Keys to abbreviations: Cr, Croton scoulcri; Pi, Psidium guajava; S, Scclesia cordata. Underlined symbols show dead trees. ８ PLOT D5 く⊃ ∩ゞ兵日 こ」 ｏ産 回 ｍ Σ ５ Ｚ 6-9 9-12 12-15 15-18 18-21 DBH CLASS (cm) Fig.77。 DBH htttogram of Plot D5. Keys to □ 圏 ■ Cr l■ cr(dead) abbre▼ iations:Cr,Craro■ scO“ Jθ ;町,Psj″ ″ 硼 others “ “ g“a」 ila7a;S,ScaJgstt cardara. 一- 68 -一 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) 10mX10m Fig. 78. Crown projection diagnm of Plot D12 shoring the regeneration of Scalesia around a parent tree. Keys to abbreviations: Dv, Darwiniothamnus lancifoliur; Pj, hidium guajava;, S, Scclesic andata; Tf, Tourmefortia rufoserbea. PLOT D12 理 ‥ ら 言 2-3 3-4 HEIGHT CLASS (cm) Fig. 79. Height histogram of Scalesia cordata □ sapling saplings in Plot Dl2. Scalesia forest is not closed in Site D probably ground . Psidium has a drought-resistant feature, because of arid conditions, Psidium easily invades but it prefers rather moist habitats with soils. It canopy gaps of the forest. Psidium has already seems that it invades first into a moist place like made a mixed forest, 4 m high, with Scalesia the bottom of a gully (Plot D20) (Fig. 81) and cordata near the camp site (Plot D2; Alt. 780 m). then spreads to drier habitat around the place. Matured trees of Psidium fill vacant space Seedlings and saplings of Psidium were found among Scalesia trees (Fig. 80), though they are around the parent trees in Plot DzO. still all thin (max. 5.4 cm DBH). Saplings and Plot D6 is located in a depressed place with seedlings of Psidium (0.65 m-2.3 m high) are also some amount of soil at the lower altitude (Alt. found in the plot. Blainvillea dichotoma and 420 m). The canopy, 6 m high, is closed except Anthephora hermaphrodita cover the bright for a canopy gap which was made by the death of ―- 69 -一 Regional Views No. I | 1997 T1 :6 T2:s S:x 10mX10m Fig. t0. Crown projection diNgran of Ptot D2 showing the invagion ol hidium in the Scalesia forect. Keys to abbreviations: Ch, Chinuca alba; Co, Cordia leacophlyais; Pi, Psiilium gyajava; S, Scalesia cordata; Tf, Touraefortit rufoscricea. -3m FfS. El. Profle diagran of Plot D20 rhowing the invasion ol hidium along a gnall vdley in the Scalesio forest- Keyr to abbreviafionr: C-n, Cordia leuaphl@is; Pl, Priiilium Suajavai Pt., hcridium aquilinum; S, Scabia cordatai Tl, Toaraetortia rufucricu. two big Sca lesia trees (Fig. 82). Psidium guajava forest: SFII at the altitude of 730 m. The loose is invading the canopy gap. As the gap has canopy is composed of large crowns of Psidium already been occupied by the crowns of Psidirffi, and smaller ones of Scalesia (Fig. 83). Lava no seedlings or saplings of Scalesia were found in rocks are exposed on the ground. There is no the gap. Small trees and shrubs of Zanthoxylum moss coverage over the ground. The crowns of fagara are abundant in the lower layers of the Psidium guajava overlap with each other. The plot. Three species of Tournefortia grow together DBH class histogram shows that Scalesia has a in the T2-layer. diversified distribution with a mode of 6-9 cm Plot D I I is located in the remnant Scalesia class (Fig. 84). Psidium guajava is thin (max. 6.0 70 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) 5m- * Fig.82. Proffle diagram of Plot D6 showing the invarion of hidium in a canopy grp of Scclesia forect. Keye to abbreviations: Cr, Cmton scoalerii Pj, hidium guqjavai S, Scalesin cordatt; Tf, Tournefortia rtfonriceal 7,1, Zanthoxylum fagam. Underlined rymbolo show dead hees. 10mX10m FiS. 83. Crovn proJection dirgnn of Plot Dll chowlng the invasion ol lrlidiam in the Scalesia forecl f,eyr to abbreviatione: PJ, hidium guqiaw; S, Scalecic cordata; Tf, Tourmefofiia rufucrbu. 7l Regional Views No. 1l 1997 PLOT Dll 賀 マ ⊃ Ｑ 昼壼 ｏ 日冒 ２ Fig. 84. DBH histogram of Plot D11. Keys to abbreviations: Pj, Psidium guaiavai S' Scalesia cordata. :0 Sapling:05-lmメ ,lm(o 10mX10m こ_ミ ′/ Ъ .:。 。 /) ( 亀 x/′ 1 ヽヽ ヽ 、 一 / -‐0 0x P /1 。:l 卜 ′ 0X0 000 o ↓ く⌒ xX O領 ∫ 0° /⌒ヽ。 ノ Jノ メ. ｘ J° 。Ｏ ｘ Fig. 85. Distribution map of Psidium guajavc (Abbr.: Pj) in an open place in Plot D13. cm DBH) for its large crown. Darutiniothamnus which is composed exclusively of Psidium is usu- lanceolata is frequently distributed in the Shrub- ally closed. Blackish lichen hangs from branches layer. at the altitude of 500 m. plot D 13 (0' 5 l'2',1" s, 9 1o I I ' 51" \M, Alt. 670 (5) Psidium guajava forest m) is located at the upper limit of this forest. It A vast Psidium guaiava forest continues from seems to be a front of mass invasion of Psidium Alt. 400 m to Alt. 700 m in the southern part of guajava. There is only one adult tree (4 m high, Site D (see Fig. 39). This may be the northern 6.5 cm DBH: maybe a pioneer in this area) of end of the Psidium dominant forest which I sur- Psidium in the plot (Fig. 85). There ate 78 veyed in Site C. Canopy trees are not so tall (3-4 saplings with a height of more than I m, and 75 m high) and stems are all thin. Most of them take with the height between 0.5 m and I m, growing a multi-stemmed growth form. The canopy layer densely in the plot. Many seedlings (less than 0.5 一- 72 -― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) PLOT D13 0 0-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 Fig.86. Height hおtogram of Fs″ J“ ″ g“aJilava HEIGHT CLASS (m) and the ratio of indi▼ iduals with■ owers or n門 dt 圏囲 No. ― % in each height cltt in Plot D13. 10mX10m ａ ″ ｒ Ｘ り ― ′ ″ ″ μ 1′ イ ′″′ 、 ″ l′ グ ａ ′ ヽ Ｘ ヽ ｒ θ ０ ″ Ｖ ′ 口 メ ・ X ′ も ヽ ′ χ ・ Ｘ イ ｔ ′ ノ ル″ ノ Fig. 87. Distribution map of psi.dium guajaya (Abbr.: pj) in a meadow in plot D14. m high) are also found in the plot. The height site to Plot D13. The south wind is prevailing. class histogram shows an L-shaped distribution, Some saplings of Psidium guajava appear in a which means the invasion is proceeding (Fig. 86). herb land, 0.5-l m high, which consists of Abuti- The largest sapling was 2.4 m high and 4.1 cm lon depauperatum, Stachytarpheta cayennensis, DBH. The ratio of the individuals with flowers or Rhynchosia minima, Acalypha pamula, etc. The proportional g6). fruit is to the tree height (Fig. largest individual of Psidium saplings is 1.3 m Even a small sapling of 1. I m in height has fruit, high and has fruit. The distribution of saplings is though the number of fruit is small. The distribu- patchy (Fig. 87). tion of saplings is patchy rather than uniform, Plot D15 shows the invasion of Psidium gua- because a fruit includes many seeds and they are java in a Pteridium aquilinum thicket at the dispersed by birds and feral animals. There are higher altitude than Plot Dl4 (Fig. 88). There paspalum open spaces in the plot where con- are three established trees of Psidium, 2.3 m, 2.5 jugatum and Abutilon depauperatum cover the m, and 2.8 m high, respectively in the plot. Each ground. takes a multi-stemmed growth form. Saplings of Plot D14 is located on the way from the camp Psidium, O.7 m-1.65 m high, are patchily dis- ―- 73 -― Regional Views No. 11 1997 10mX10m T1 :O T2.s S:x Fig. 88. Crown projection dhgrsm of Plot D15 showing the invagion ol Pridium in a Ptcridium thicket Keyc to abbreviations: Dv, Darviniahamnus tnncifoliusi Pi, Psidiam guajava; Ptl,, Pbtidium aquilinum. tributed around the parent trees. Pteridium Scalesia are also found, but Croton ts tate. grows well under the extended crowns of Psidium Crowns of Scalesia become small, and saplings trees, probably because of protection from the of Croton increase abruptly on the gentle slope of strong prevailing wind. the middle part. Scalesia disappears and Croton There is a large patch of Daruiniothamnus trees with thin stems and small crowns grow scrub near Plot D14 at the altitude of 760m. densely making a loose canopy on the steep slope The scrub seems to be a substitute of Miconia of the lower part. Some dead trees of Croton are robinsoniana scrub in Santa Cruz which is not found here. A small tree of Psidium guaiava found in Isabela. invades this part. Pteridium aquilinum makes small patches in the upper and the middle part, (6) Croton dominant forest but it disappears in the lower part. Other herbs Croton scouleri becomes dominant on drier such as Blainvillea dichotoftia, Synedrella nodifl- habitats (thin soil and low humidity) in the lower ora, Sida salvifolia and Rhynchosia minia are altitude compared with Scalesia cordata. Plot D common throughout the plot atea. Croton forest 17 is a belt-transect which was put on a slope at like this appears on the north (leeward) side of a an altitude of about 730 m. The plot atea is ridge near the remnant Scalesia forest (SFIII). divided into three parts: ( 1) upper part (Scalesia plot D16 (0o50'40"S, 91o 1l'46"W, Alt. 700 dominant forest) , (2) middle pafi (transitional m) is a Croton dominant forest, 3-4 m high' near forest), and (3) lower part (Croton dominant the crater (Fig. 90, Fig. 9l). The ground is forest) (Fig. 89). Scalesia trees with a large mostly composed of exposed lava- Stems of crown make a sparse forest, 4-5 m high, on the Croton are all thin (max. 7 .4 cm DBH) and strai- flat place of the upper part. Young trees of ght (Fig. 92). There are some dead trees, but 74 Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) Fig.89. Ctown projecdon dirgmm of Plot D17 showing the transitiond part betreen Scalsia forest and Q1p1412 ilsnimant foreet. f,eys to abbreviationgz Bt, Burtcm gmvulensi Co, Cordia leucophlyctis', Cr' Croton tcoulerii Dv, Darwinbthamnus hncifolius; Pi, Psidium Su4java; Pt' Ptcridium aquilinun; S, Scalzsia andan3 TI, Tournalofiia rufuericea; Zl, Tanthoxylm fagara. Fig. 90. Profile diagram of CЮlわπ dominant forest in Plot D16。 Keys to abbreviations: Br, Burcera jj;S,Sむ graveolens; Cr, Croton scoulerii Phr,Phο rada降 ごro■ λttJoッ αJas'α cordata; T f , Toumefortia rufosericeai Zf, Zanthoxylm fagara. they include various sizes of trees. The canopy this habitat. Herb species are common to the which is made of small crowns is not closed fully. Scalesia forest in the upper elevation. Parasite of Phoradendron henslovii is very fre- plot D4 (0"50'51"5,91" 1l'56"W, Alt. 650 m) quent. This must cause the death of Croton to is a Croton-Scalesia mixed forest on a flat place some extent. Saplings of Croton are also growing with some amount of soil. Scalesia trees have frequently. Four individuals of Scalesia exist in large crowns in the canopy layer (Fig. 93). A the canopy layer, but no saplings or seedlings of multi-stemmed Psidium guajava also spreads its Scalesia are found in the plot. The existence of large crown in the canopy layer. I found a thick Bursera graveolens shows the arid condition of dead stem at the center of the clump, so this ―- 75 -― Regional Views No.11 1997 丁1:o 丁2:e S:λ deadi. 10mX10m COO 0 Fig. 91. Crown projection diagram of Croton dominant forest in Plot D16. Keys to abbreviations: Br, Burtera graveolensi Co, Cordia leucophlyctis; Cr, Croton scouleril S, Scalesia cordata; Tf, Tournefortia rufosericeai Zf , Zanthoxylm fagara. ＜ ａ ４ ｓ ｅ パ ｚ ｂ 蚤 冒 ヨ 12-15 15-18 □ 囲 DBH CLASS (cm) ■cr ■ cr(dead) 剛Others ●∽ 習 ８ 〓 ２ ６ 国 冒 ヲ 6-9 9-12 12-15 Fig。 92. DBI・ I histogralm of CrarO“ dOlmilant DBH CLASS (cm) forestt in Plo撻 D4 and D16。 Keys to □ ■ ■Cr abbre▼ iations:Cr,Craro■ sca“ ルだ;町,PsJ″ ″ (dead) others “ 剛 g“a」avα ;S,Scaras,α carda". ―- 76 -一 Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu) 10mX10m FiS.93. Crown projection diagrem of Scalsia-Crotan nixed forest in Plot I)4 showing the invasion of Psidium. Keys to abbreviationc: Br, Bancra grawlerci 6, Chiococca alba1, Cr, Cmbn scoaler| Pg, hidium galnpagciumi Pj, Psidium gu4javai S, Scalasia cordatai Tl, Tourwfottia ruloscrieca, Zl, Tantlnrylm fagam. individual probably originated from sprouts after seems to be unstable. Only Polypodium tridens the predecessor's death. Many small trees of grows within the lava flow apart from the forest. Croton make small crowns in the canopy (T1) Plot D19 is a mixed forest on a slope (Inc. 15') and T2-layers. However,42Vo of Croton individ- in the Semi-arid zone at the lower altitude uals in these layers are dead maybe because of (Alt. 450 m) (Fig. 95). Scalesia cordata, Pisonia heavy parasite of Phoradendron henslovii. It is floribunda, Sapindus saponaria and Bursera strange that this parasitic plant does not attach graveolens make the Tl-layer: 6-7 m high, and Scalesia here, though it is found on the crowns of Croton scouleri, Cordia leucophryctis, Zanthoxylum Scalesia in the Scalesia forest at the upper eleva- fagara and Psidium galapageium occupy the tion (Plots Dl and D3). There are many Croton lower layers. They are all native species. This ones the zone which covers saplings, but no ^Scc lesia in the forest. A forest continues to Arid feral pig ran through the plot, while I was study- the vast lowest elevation. ing. There is a Scalesia-Croton mixed forest at the (7) "Subalpine" scrub and "alpine" meadow edge of new lava flow in Plot D18 (0"51'12"5, The Scalesia forest disappears abruptly at the 91" 12'39"W, Alt. 460 m). Two individuals of altitude of around 800 m. Above the forest limit, Scalesia cordata appear just adjacent to the lava occurs an "subalpine" scrub (paramo-like vegeta- (Fig. 94). This shows a drought resistant feature tion), though this is not a real subalpine on the of S. cordata. Pteridium aquilinum grows at the continent. fringe of the forest. Darwiniothamnus lancifolia plot D7 (0" 50'16"5, 9L" lO'54" , Alt. 840 m) exists on the lava. The lava flow is made of shows an example (Fig. 96, Fig. 97). Cordia rugged rocks with a diameter of 2V30 cm. It scouleri, C. leucophlyctis, Tournefortia pubescens 77 Regional Views No. 11 1997 Cr FiS. 94. Profle diagrrn oI Scalaia-Cmton ni*ed forest on the edge of llrva flow in Plot D18. Keys to abbrevirtions: Ca' Codia leuaphlyctisi Cr, Crcton scoulcri; Dw, Dar*iniothamnus lancifoliusi P!, Psidium gaajawi Ptr' Pteridium aquilinum; S, &alaia cordata, Fig.95. Proffle diagran of nixed forect in Plot D19 near the Semi-arid zone. Keys to ebbrevirtions: Br, Burseta gravalerc3 Co, Cordia lcaaphlgisi 6, Crctan scouleri; Pl, Pinnia floribunda, Pg, hidium galapngeium, S, Scalesia corddai *, fupinilus sapruria; Zl, Tnnthoxylum Jagara. and T. rufosericea take a multi-stemmed growth shrubs of Cordia leucophryctis and Tournefortia form, making large crowns , 2-3 m high, here and rufosericea make tussocks 2.5-3 m high, and there. Daruiniothamnus tenuifolius, D. lancifolius Altenanthera echinocephara and Darwiniothamnus and Baccharis gnidiifolia with smaller crowns are tenuifoliium are dominant in the open space in distributed among them. Cassia picta is also this plot (Fig.98). As Altenanthera echino- frequently distributed. A young tree of Scalesia, cephara is a member of the Arid zone on the 1.8 m high, exists, isolated, in the plot. The windward slope, its existence indicates the aridity Herb-layer consists of Blainvillea dichotorna, An- of the habitat. It is characteristic that two thirds thephora hermaphrod it a, Syned rella nod iflora, Sid a of Cassia picta individuals are dead. Herb species spp., etc. The species composition is nearly com- are common to Plot D7. These scrubs (Plots D7 mon to that of the Scalesia forest below. and D9) may be comparable to the Moist-scrub plot Dg (0"50'05"s, glo 11'19"w, Alt. g10 m) zone in Santa Cruz, but the habitat is dry, the is located beyond a strip of lava flow which altitudinal range is narrow and the species com- borders the Scalesia forest at the north end. As it position is different (no Miconia robinsoniana). is drier at this north side of the lava flow than on Pteridium aquilinum ("alpine" meadow) makes the opposite south side, "subalpine" scrubs and a vast dense thicket, 1-1.5 m high, at the altitude "alpine" meadows descend to lower elevation in- above 840 m (Plot D8). The density (the number stead of Sca lesia forests (see Fig. 39). Two of petioles) of Pteridium was 13-16 per sq. m. 78 Competitive Relationships between Tree Species of Sca/es ia and Introduced Plants (Shimizu) T2:o S:r 10mX10m FiS. 96. Ctown projecdon diagram of "cub-alpine" scrub in Plot D7. Keyc to abbreviatione Ba, fuccharis gnidiifoliai Cn, Cordia buuphlyctis; Dvl, Darviniotlumnus lnrcifoliusi Dvto Dtrviniotlwmnus tenuifoliru; S, Scatrasia cordata; Tl, Tourmelortia rulosericaT Zl, Zanthoxylum fugara. (a) PLOT D7 PLOT D9 Fig.97. Proflle dirgnn of "oub-alpine' scrub in Plot D7 and D9. Keyr to abbrevirtiong: A\ Altenanthem ehhtuepharaS Co, Cordia leuaphlyctis; Cp, Cassia pictai Dvl, Darviniothamnus lnrcifolius; M,, Darviniathtmnus tanuitolius; S, Scatrasia cordatai Tl, Tournefortia rufuericca; Zl, Zantlnxylum fagaru, 79 Regional Views No. 11 1997 丁2:o S:x 10mX10m ％ ヽ た 卍 ス ＾訓 ０ ヽ ゝ 一 一ヽ、 『一、 1九 〕 tメ 班 ,■ ′ . xixnl ・ ′メtth ´ Xハ l; 〆…… Ｘ イ rr2.tiil く。」 /´ ノ i',qt ' ｀ --I '.-- - '((′ X tも x ".. 葛 ケ ANi 〕 、、1lrギ 、 )( ， や 一 一、 「．‐ 劇 ヽ‘ ・ヽト′ θ ｒ ′´。．■ ′『目 」】 一 千 ‐ ” ゝ ● ヽ t taa ,-t- ヽノ t. ヽ一 ヌ ,, ttt ilttL ． xi ´ ″ ． θ′Ｘ Dw ..r ´ ヽ ´Ａ ta ｘ４」 ′‐ a"t' ハ‐′ ・ ′ ヽ ヽ ／ ヽ ／ ） ヽ 、 ‥ｘ 。 メ 嗅 院 ‐ ノ ″ ヽ 争 ヽ ヽ ／ tノ :〕 、 xハ 々〕彎 Altenantlleta Fig. 98. Crown projection diagran of "sub-alpine" scrub in PlotDg. Keyc to abbrevirtions: At, uhinwphara; Ba, Baccharis gnidiifolia; Co, Cordia leucophlyctis; Cp, Cassia pictaT Dv, Darwinbtlumnus tenuifoliusi Tf' Tourrcfortia rufosericea. -15m Fig. 99. proffIe diagram ol Pteridium thlcket ("alpine" meadow) in Plot D8. Keys to abbreviations: Co' Cordia leacophtyctis; Ptr, Ptefidiam aquilinum; S, Scolesia cordata,Tf,Tournefortia rufosericea' Woody species of the scrubs below are sparsely Dr. Gjitte de Vries at the upper limit of the distributed in the Pteridium thicket, extruding Scalesia forest near the camp site. There were 9 their crowns 2-3 m high (Fig. 99). The floor of trees of Scalesia inthe quadrat before the El Nifro the thicket is so dark that no herb is found except event in 1983, but they all died from unusually one individual of Eleocharis sp. The Pteridium much rain at that time (de Vries & Tupiza 1990). thicket goes down to the lower elevation in a There is no Scalesia now in the quadrat. moist valley, while a scrub of Macraea laricifolia goes up to the upper elevation on a dry rocky (8) Why are the remnant Scalesia forests left ? or ridge in this area. The Pteridium thicket is com- Almost all Scc lesia forests were destroyed parable to the Highland zone in Santa Cruz. disturbed by humans, feral animals and intro- are some There is a permanent quadrat ( 10 m X 10 m) of duced plants in the Site C area, but there -80- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Scalesia forests (SFI, II, III) left in natural condi- because of the interference of magnetic effect of tion in the Site D area. Why ? One possible lava rocks. There is a trail from the coast to the reason is that there have never been disastrous mountain top. We set our camp site at the disturbance like fire and cultivation after cutting altitude s7o m (0o 23'19"S, gl" 04'51"w) beside in the past which could accelerate the invasion of the trail. Psidium guajava. The second idea is that these Scalesia microcephala, the third tree Scalesia, forests are located far from the inhabited area makes a sparse forest with Bursera graveolens (source area of introduced plants), so Psidium (35f550 m) and with Trema micrantha (55O- arrived here relatively recently. The third is that 700 m), and forms a parkJike vegetation with this place is the northern limit of the Scalesia herbs and grasses (70f850 m) (Fig. 100). It also cordata distribution, and Psidium is not good at makes a dry scrub on the rim of the crater. growing in such a dry habitat, even though they Scalesia afinis, a shrubby species, appears at the can endure dry conditions. So the invading speed drier, lower altitude (below zDm). The two of Psidium is slower here than in the moist wind- Scalesia species occur separately along the altitud- ward area. As the canopy of Scalesra forest is not inal gradient. It is noteworthy that no introduced closed in this area, it is easy for Psidium to invade trees and shrubs are found throughout the area. the forest. Psidium is, in fact, invading and It is reported that feral goats are destroying the establishing in the forest. Scalesia scrub on the moist part of the crater (not On the contrary, I did not find any proof that included in Site E). A major Alcedo Campaign the Sca lesia forest is spreading outward. As the was initiated in 1995 to eradicate feral goats and prevailing wind blows from the south, the seeds monitor long-term change of vegetation and tor- cannot be dispersed to the moist direction. The toise populations (Cayot & Snell 1996). I found remnant Scalesia forests (SFI, II, m) are sepa- some feral goats on rocky places around the rim rated from each other by grass or herb lands, of the crater. Giant tortoises are living in good where I did not find any Scalesia seedlings or condition at the upper part of the mountain and saplings. The present habitats of the remnant inside the crater. Recently tourists visit the crater forests are confined to flat or depressed places, frequently to look at the giant tortoises. but these forests might have covered the whole area when moister climate governed this area in (2) Scalesia-Trema mixed forest (Middle eleva- the past. tion) Scalesia microcephala makes a sparse forest 5. Site E (Alcedo) with Trema micrantha at the middle elevation ( I ) Location (550-700 m) of this area (Plots El, E2 and E3). Alcedo (Alt. 1128 m) is an active volcano The canopy is usually low in height (3-4 m), and which is located at the middle part of Isabela the coverage is small (lV3OVo) (Fig. 101, Fig. (north of Perry Isthmus). We can see the geyser lO2). So the sun light penetrates directly into the inside the crater. I studied the vegetation of the forest. The forest includes Scalesla individuals of north-east slope of the volcano from the coast all developmental stages i.e. seedlings, saplings, (Playa Negra: O"2l'18"S,91"03'O4"w) to the young trees, matured trees and dead old trees rim of the uater (about 1100 m) (Fig. 100). This (Fig. 103). The situation is rather similar to that place is a transitional zone between the moist of the Scalesia cordata forests in Site D. The windward (south-east) slope and the dry leeward largest tree of Scalesia is 5 m high and 10.4 cm (north-west) slope of the mountain. The prevail- DBH. Big trees of Trema (5-6 m high) are ing wind from the south is pretty strong, but the scattered in the forest. They usually branch into cloud coming from the windward direction disap- several stems at the base, thus taking a multi- pears before it reaches here. stemmed growth form and making a huge crown As thick pumice and ash layers cover the whole (Fig. lO4, Fig. 105). Saplings of Trema are also area from low to high elevations, the thin-soiled found. Both Scalesia and Trema produced much ground is dry. There is a wide black belt of new fruit at the time of this survey. Large trees of lava flow which separates the area from moister Pisonia floribunda are also distributed sparsely east-facing slope. A ditch (about 5 m wide, 5 m (Fig. 106). Its huge multi-stemmed growth form deep) originated from fluentlava flow runs paral- is common to that found in Site C. It is strange lel with the lava belt from the ridge to the coast. that few seedlings of Pisonia are found. Strangely, my compass did not work here maybe The soil layer on a deep pumice accumulation is -81- Regional Views No。 11 1997 A■ cedo(Site E) Dry ハ Rim of Crater ー ー ー ‥ ８ ５ 。 ｍ 一 ∽ Ｑ ” 卜 Ｏ ｍ 卜 ７ 。 。 ｍ ． 一 ” ｅ Ｓ ｔ ヨ ●爾月 Ｆ Ｑ ‐ Ｈ ｏ Ｑ Ｄ Om ヽ ド : ” l ScaJ'.esi a-Bursera 卜 Ｕ l ” 卜 : Mixed Forest け l日 Ｏ :H Ｆ :" l= 350m : Ｆ ” く Bursera Forest & Scrub ” 『 Ｐ ハい ‐ Ｏ 〓 ‥ 。 ” ■50m ｈ Ｌ ド Arist,ida Grassland ● 卜 ． _ ゴ児J“ 眈 FIg. 100. Schematic precentation of vegetational zonation and disbibution ol tvo Scalaia species in Site E (Ncedo, Isabefl). very thin, and the surface is arid. There is no growth form making alarge tussock in the Shrub- moss coverage on the ground, and lichen on layer (l-Z m high). Cassia picta and Baccharis trunks is also scarce. The Shrub-layer is exclu- gnidiifolia are also abundant in the Shrub-layer. sively dominated by Walteria ovata and Macraea The flora of the Herb-layer is basically similar to laricifolia. Both species have a multi-stemed that of Site D. Blainvillea dichotoma, Rhynchosia 一- 82 -― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimi"u) 10mX10m ｉｔ Ｘ x i WX 一 一 ヽ――‐げ ヽ‐‐ _、 をｘ : ′′ ノ ヽ I〔 Wヽ ｝ 三 ＳＸ ンrP) ′‐｀｀｀ ′ ｀ 卜S XS tt_｀) ' ″ X,f´ ′ ′ II Ｗ” Ｘ ふ ヽ ヽ ヽ ヽヽ＾ ″ ) f XM)〆 可 ヽ‐″′ ・ 1ご 一 ｘ メ Ｍ ゝ 一 ｘ Ｓ S・ ノだ ン1｀ Fig. 101. Crown projection diagram of Scalesia forest in Plot El. Keys to abbreviations: Br, Brusera graveolens; Cp, Cassia picta; M, Macraea laricifolia; S, Scalesia microcephala; Tr, Trema micrantha; W, Waltcria ovata. Fig. 102. Profile diagram of Scalesia forest in Plot El. Keys to abbreviations: Br, Brusera graveolensi M, Macraea laricifoliai S, Scalesia microcephala; Tr, Trema micranthai \il, Wsltcria ovata. Underlined symbols show dead trees. minima and Sida spinosa are dominant. Their covers small shrubs frequently. real density is not so high, even though the cover- age percentage is apparently high. In addition to (3) Scalesia parkJike forest (Upper elevation) them, Cenchrus platyacanthus, Aristida repens, Large trees of Tremc disappear gradually, and Stylosanthes sympodialii, etc. are frequently dis- a park-like forest of Scalesia occurs at the altitude tributed. A parasitic plant, Cuscuta gymnocarpa, of 700 m and above (Plots E5 and E6). The ―- 83 -一 Regional Views No。 11 1997 ＜ ａ 胃 PLOT El Ｓ ｐ 魚 Ｚ ｂ 蟹 冒 ヨ 1-2 2-3 3-4 4-5 5-6 HEIGHT CLASS (m) □ s ■l s(dead) ■Tr ● コ マ 涸 冒 ２ 【 ６ 蚤 冒 ヲ L-2 2-3 3-4 4-5 HEIGHT CLASS (m) tls Irr “ ▼ PLOT E3 〔 コ く ⊃ ∩ ゞ 賽 日 ‘』 〇 ∝ 国 田 ≧ ⊃ Ｚ _躙 _ Fig. 103. Heieht histograms of Scalesia forests 2-3 3-4 4-5 5-6 in Plots El, n2 and E3. Keys to abbreviations: S, llEIGHT CLASS(m) Scalesia microcephala; Tr, Trcma micrantha. □ s ■l s(dead) 圏Tr 20m T1 :O T2:s S:x Fig. 104. Crown projection diagram of Plot E2 chowing the regeneration of Scal.aia. Keys to abbreviations: Br,, Baccluris Criiliilolbl Co, Cordia anhonii; M, Macraw laricifoli.a; S, kolasia miouephala; Tl, Tourmefortia pubaceu;Tt, Trcna mbmnthqV, WaI.Eria ovata. 一- 84 -一 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) PLOT E2 PLOT E3 Fig. 105. Profile diagrams of Plot E2 and E3 showing the regeneration of Scalesia. Keys to abbreviations: Cp, Cassia picta; M, Macroea laricifolia; S, Scalesia microcephala; Tf, Tournefortia pubescens; Tr, Trema micranthai \il, Waltcria ovata. Fig. 106. Typical growth form of Pisonia fl.oribunda in Site E. canopy height decreases to 3.5 m, and each crown Balinvillea dichotorrta, Anthephora hermphrodita becomes small (Fig. lO7, Fig. 108). The largest and so on. Bumble bees visited flowers of Clotara- individual of Scalesia is 3.5 m high and 10.9 cm lia incana frequently. Many seeds of this plant DBH in Plot E6. All developmental stages of were dispersed on the ground at the time of Scalesia are found here, too (Fig. 109). Dense survey. Sparse distribution of Scalesia crowns thickets of Walteria and Macraea which feature and the dense herb coverage on the ground make the Shrub-layer of the middle elevation disappear a park-like physiognomy (Photo 9). Giant tor- in this altitude. Instead, Tournefortia pubescens, toises seem to appear in connection with the T. psylostacya, Cordia leucophlyctis and Zantho- occurrence of this type of vegetation. zylum fagara which are common to Site D mainly Plot E4 is located at the foot of the rim of compose the Shrub-layer. The Herb-laY€r, 0.8 m crater (o"24'41"S, 91"05'21"\M, Alt. 810 m). high, is densely covered with Crotalaria incana, As the place is on the south-east facing slope of a 85 Regional Views No。 11 1997 ..park-like" Fig. 107. Profile diagram of Scalesia forest in plot E6. Keys to abbreviations: Clt, Clotalaria incana; Co, Cordia leucophlyctisi S, Scalesia microcephala; Tf, Tournefortia pubescensi Zf, Zanthoxylum fagara. 10mX10m （ (1,) 日 f Xs S ） II｀・、 ｒ ｀一″ “一 一『 CI)｀ ´｛に´ 〕 嶽 ヽ ‐ ヽもヽ ノ I｀ヽ ．ヽ七 澤ｒ ´ 「ギ ∫J′ 1 て ヤ ｛:Iヽ 事 〔 ¨‐‐´ ● 蒙て三) si｀ :′ 暮 一 ・ ） ¨ ｒ ″ 11:)(勢 熟 ′ ″ Xs ｒ ′ Ｓ 一 堪:ゝ t、 Li ｔ ｘ ヌs l」 ゝノ~ IIメニ) i、二″′l● ｀｀ ′ ｀、「 負 ヽ Co メ ＞ 一 〆 ■ ヽ ｘ x Ffg. 10E. Crcwn projection diegrrn of '!nrk-lile" Scalaia forect in Plot E6. Keyr to abbreviefionc C-o, cordia leaaphfrurir; s, scz,lrrlia micrryluh; Tf, Touraefurtia pubaensi z,l, za ntlnxytum fagara. small ridge, it is sometimes shrouded by fog and m high and 33 cm DBH. It forms a large crown therefore moister than the north-west facing slope whose leaves were mostly shed at the time of (Plots E5 and E6) on the opposite side of the study. A large amount of white, hairy lichen ridge. Strangely, there are no Scalesia trees on (Usnea sp.) hangs from the branches. This shows this side. Large trees of Burcera graveolens ate the high humidity at this site. Large trees of scattered in the dense grass and herb land (Fig. Trema micrantha are also distributed sparsely, 110, Fig. 111). The Bursera tree in the plot was 5 but there are no saplings in the plot. Some species 一- 86 -― Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) ａ 鴇 PLOT E5 て ⊃ Ｑ Σ 一 Ｑ 乙」 〇 ∝ 国 田 ≧ Ｊ Ｚ 0-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 11EIGHT CLASS(m) □ alive l■ dead ｂ 鴇 マ ⊃ 口 Σ 口 乙 』 り ∝ 【 ワ ５ Ｚ 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 HEIGHT CLASS (cm) Fig。 109. Height hお torams of ScaresJα Jc“ alive l■ □ dead ′λαJa in Plo"E5and E6. “ Tl:o 丁2:o S:x 10mX10m Ftg. 110. Crorn projection dlagram of Plot E4 showing t l*ge Burcat hee and sone oth€r chnrbs ir a dence gnsc.herb lanrl Keyr to abbreviation$ Bt, Burw'lra graveolens; Co, Cordia leucophlyctisi Pg Psidium galapgeiumi fi, Tournefortia pubacana'S Ttr, Toamefortia rufoseri.ca; zf, Tanthoxylum fagam. ―- 87 -― Regional Views No. 11 1997 Fig. 11l. Proflle diagran of Plot El rhowing t large Butrrlra tree and some other shrubd in a dence grrsc.herb land. Keys to abbreviations: Elt, Buneru gmveoIensT Co, Cordia leuaphllctis; Pg, Psidium galapagcium;Tftg, Tounufortia pubescerc;Tfu, Tourrcloftia rafoseriw3 Zf, Zantlntylum fagam. ｏ ” “ Ｃ “ ｍ Fig. 112. Profile diagram of "sub.dplne" scrub ir Plot 812. Keyr to abbreviation* CJ[, Clotahri4 Ｍ Co, Cordia leuaphlyaisi Dv, Darwiniotlumnus bnuifolius; Pen, PcnnJE&.m paupcrumS Pg, galapageium3TSg, TourmeJortia pubcsrrlrlaiTfr, Tournefortia rufowrim; Zf, Zanthoxylum fagara. such as Cordia leucophlyctis, Tournefortia rufoseri- tortoises live in this grass and herb land. Herb cea, T. psilostachya, Psidium galapageia and Zan- and grasses are pressed down to the ground to thoxylum fagara make clumps here and there. make an instant path, 5f80 cm wide, when tor- The HerbJay€r, 0.8-l m high, is so developed toises walk through this place, so we can pursue that it is difficult to pass through the plot. Grasses them easily. and herb are vigorous compared with those in the Scalesia microcephala disappears once at the drier slope on the opposite side. Blainvillea dicho foot of the rim of crater. A kind of dry scrub, toma, Chenchras platyacanthus and Anthephora 1.5-2 m high, which is similar to the "subalpine" hermaphrodit are dominant, making dense cover- scrub in Site D occurs on the steep and rocky age over the ground. This may prevent Scalesia outside slope of the rim (Plot Bl2). It consists of seedlings from establishing in this place. Giant Darviniothamnus tenuifolius, Psidium galapag- 88 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimi"u) eium, Tournefortia rufosericea, T. pubescens, Scalesia in the plot. The Herb-layer is nearly the Cordia leucophryctis and Zanthozylum fagara same as that in the lower elevation, but it seems to (Fig. ll2). The species composition of the Herb- be under pressure of grazing by giant tortoises layer is nearly the same as that of the lower and feral goats, because the herb is short like altitude. Only atall grass, Pennisetum pauperum, mowed lawn except for large tussocks of Pennyse- is characteristic to this scrub. I saw a herd of tum pauperum. In fact, I found a big giant feral goats which had brown hairs with white tortoise grazing grass within the plot (Fig. I 14). patches, grazing in this scrub (Photo 10). Pteri- Some naked lands exist on the ridge which were dium aquilinum makes a dense thicket over the attributed to grazing and trampling by giant tor- steep slope of the rim locating to the north of this toises and feral goats. Feral goats are not only place. competing with giant tortoises in food resources, Scalesia microcephala appears again on the but also destroying their habitat (Munoz 1993). I ridge of the rim of the crater at the altitude saw a Scalesia dominant forest standing on the around 1100 m. Plot E7 was put on a west facing south pafi of the ridge which received more mois- slope inside the crater (0" 25'Ol "S, 9l'05 ' 48" W, ture from the south wind, though I could not get Alt. 1070 m). Scalesia makes a scrub, 3 m high, there in this study. It is reported that feral goats together with other shrubby species such as are causing destruction of the forest (Cayot & Cordia leucophrictis, Tournefortia rufosericea, T. Snell 1996). A dry-type vegetation of Bursera pubescens, Psidium galapageium and Zanthox- and Walteria are found on the dry bottom of the ylum fagara (Fig. 113). Most of them take a crater where bare lava is exposed widely. multi-stemmed growth form (Fig. Ll4). Espe- cially, Cordia leucophrictis had 5.8 stems per indi- vidual on average. I found only one seedling of T2:o 10mX10m Fig 113. Crown projection diagram of Scalaia gcrub in Plot E7. Keyr to abbreviation$ C;o, Cordia hucophlyctisS Pen, Pennyvtum Inuperam, Pg hidium galapgeiam; Tfg, Tounufortia pubmns; Ttr, Touruefonia rafuefieai 7'f, Tanthoxylum fagam. 89 Regional Views No. 11 1997 qN\(ff3' h Fig. 114. Profile diagram of Scalesia scrub in Plot E7. Keys to abbreviations: Co, Cordia leucophlyctis; Pen, Pennysetum pauperurni S, Scalesia microcephala; Tf' Toumefortia rufosericea; Zf, Zanthoxylum fagara, (4) Scalesia-Bursera mixed forest (Lower eleva- growing in the neighborhood is a feature of the tion) transitional forest (Fig. I 18). Scalesia micro' The number of Bursera graveolens increases cephala is also sparsely distributed. The Shrub- and Trema micrantha disappears at the lower layer is dominated by large clumps of Macraea altitude (below 550 m), while Scalesia miuo- and Walteria, but it includes a variety of shrub cephala continues to be canopy trees (Plots E8 species such as Cordia leucophlyctis, three species and E9) . Bursera attains to 6 m high, making a of Tournefortia, Cassia picta, Chamaecyce vim- large crown (Fig. 115, Fig. 116). It shed leaves inea, Danviniothamnus tenuifolius and Lantana and had fruit on the bare crown at the time of this peduncularis. The Herb-layer is composed of study. The largest tree of Scalesra is 3.5 m high both the upper elevation elements (Anthephora and 8.5 cm DBH in Plot E8. No lichen hangs hermaphrodita, Cenchrus platyacanthus, Clotara- from branches. As the canopy is not closed, all lia spp., Bidens riparia, Zornia piurensls) and the developmental stages of Scalesia from seedlings to lower elevation elements (z{rustida divulsa, Tephr- mature trees are found here, too (Fig. ll7). osia decumbens, Boutelona dis(icha, Polygala gal- The Shrub-layer becomes sparse compared apagoensis, Chamaesyce punctulata) together with the middle elevation. The dominancy of with common elements (Sila rhombifolia, Rhync- Walteria ovata and Macraea laricifolia decrease hosia minima, Stylosanthes sympodialis, Ipomoea and instead, Lantana peduncularis, Chamaesyce triloba), which shows the transitional feature of viminea and C. punctulata appear . Castela galapa- this place. geia and Scutia pauciflora which are originally the Scalesia microcephala disappears rather abrupt- members of dry vegetation also occur to some ly at the altitude around 3N m where the inclina- extent. The ground is covered with volcanic tion of the slope becomes steeper downward. Plot pumice and ashes. There are few fallen leaves and ElO (Alt. 24O m) is located in the altitudinal gap litters on the dry ground. The coverage value of between the distribution of S. microcephala (Alt. the Herb-layer is seemingly high, but the actual 3411100 m) and that of s. affinis (Alt. 0-210 density is low. Grasses such as Aristida divulsa, m). So there is no Scalesia here, though the Boutelona disticha, and Paspalum coniugatum structure and species composition of the forest is were dead or half-dead and the total amount of not so different from those of Scalesia-Bursera biomass was not so much at the time of survey. mixed forest above (Fig. 119, Fig. l2O). The Plot Ell is a belt transect which was put in a density of Burserc trees increases a little, and their transitional zone between Scalesia-Trema mixed crowns become larger compared with Plots E8 forest and Scalesia-Bursera mixed forest. The and E9 (see Fig. 115 and Fig. 116). As the bark existence of two large trees of Trema and Bursera color of Bursera trees is bright white, the forest 90 Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) T1 :O T2:a 10mX10m Fig. 115. Crown projection diagram of Scalesia-Burcera forest in Plot E9. Keys to abbreviations: Br, Burrera graveolenq Cg, Castera galapageia; Co, Cordia leucophlyctis; Cv, Chamaesyce vimineai Dw' Dart+,iniothamnus tenuifoliusi S, Scafesia micruephala; Y{, Walteria ovata. Fig. 116. Profile diagram of Scalesia'Burcera forest in Plot E8. Keys to abbreviations: Br, Burcera graveolens; Co, Cordia leucophlycfis; M' Macraea laricifoliai S, Scalesia tnicrocephala; St' Sczda pnucifl'ora. looks like a white birch forest in the subalpine almost dead at the time of this study. zone in Temperate region (Photo l1). The distri- I found the first individuals of Scalesia affinis at bution of Bursera is clumpy. Al1 developmen- the altitude of 240 m along the path when I went tal stages of Bursera are found in the plot. The down the mountain. It becomes frequent at the coverag e of Aristida divulsa is high, though it was altitude of 210 m and below. The results of the 91 Regional Views No. 1l 1997 PLOT E8 ヨ ‥ む 言 0-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 HEIGHT CLASS (m) ng。 117。 Height histogram of Scaras'α ,cro‐ □ alive l■ dead 6響,Й ttJa in Plot E8。 “ 10 20m 2♀ θ 【 踊 ソリ (入fJ I x■ 串 〕 ′´ヽ I Mゝ ¨メ ヽ、 ″一” ヽ、 Xヽいヽ、 I´甘 喘 ″ ヽ “ 一 ′ イx′ 「 ′ 一 /t ‘ 喝 ・ ヽ ・ 】 ‐ ノ ふ メ ヽ ヽ ヽ ′ ヽ・´ い 、 Ｆ ｀ 一 Ｍ ´ ∩ 一 ”ヽ ′ Ｊ ′ ヽヽ 1、 、 ′ 、 ‐ 出 ｀ ‐ ヽ も ﹈ ど_` ヽ Ｘ ヽ メ 二 、 、 ¨・´ T1:O T2:s S:x Fig. 118. Clown projection diagram of Ptot Ell which wrs prt in the transitional zone betreen Scalai'a-Trcma forect and fualzrlia-Bunem forect. Keys to abbreviationsz Br, Bunem gravalens; Co, Cordia leucophlyctisS I)v' Darviniothamnw tenuifolius; M, Macmu hricifolia; S, Scatresia micruepluhi St, Scutia paucifurai Tl, Tounuefortia pubacens, Tr, Tlema mitrantha3 W, Waltcria owtt. 丁1:0 丁2:● S:x 10mX10m Fi3. 119. Crown projection diagren of Bunera forest in Ptot E10. Keys to abbreviationc Blr, Burscra gravalcwi Co, Cordia leucophlyctis; L, Lantana pcdunculafis; M, Macma larbifoliai, W, Walteria ovata. ―- 92 -一 Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) Fig. 120. Profle diagram ol Bunem forest in Plot E10. Keyl to rbbrevirtionc: Br, Bunem gravqlew, L, Lantana TndurculnrisT M, Macmea hricifolia; W,'Walhria ovatt. 5Ao^ Moist Dry Lantana-Croton Scalesia f. thicket PsidLum― Croton f。 rro AzuI Cerro Pajas 330m ttacraea - Lantana s crul> P二 こ口guajava Ceno Pajasコas Parkinsonia -Prosopis f. Scal,esia f . Bu.rsera f . (open) Post Office Bay Ihrrsera f . (cloged) Puerto Velaeco Ibara Fig. l2l. Schematic presentation of vegetational zonation in Site F (Floreana). study of ,S. affinis scrubs are described in the later 250 m in elevation (Fig. 121). Floreana has been chapter. inhabited by settlers since the early 19th century. Most of the flat area on the plateau has been 6. Site F (Floreana) exploited for pasture lands or agricultural planta- ( 1) Location tions. Scalesia pedunculata forests are left mainly Floreana is much smaller, lower and drier than on the windward (south) slope of the mountain Santa Cruz and Isabela. It must be older geologi- tops. Especially at Cerro Pajas (the highest moun- cally, too. There is a large plateau with several tain: Alt. &O m), a natural Scalesia forest exists mountain tops at the center of the island above in a small valley (eroded old crater) open to the ―- 93 -― Regional Views No. I | 1997 T1 :O T2:o S:x deadio,T 10mX10m Fig. 122. Crown projection diagram of Scalesia forest in Plot Fl. Keys to abbreviations: A, Cbrodendrum mollei, Co, Cordia andesonii; Cr, Croton scouleri; Dw, Danviniothamnus tonuifolius; L, Lantana catnara; Pi, Psidium guajava; S, Scclesia pedunculata. s Fig. 123. Profile diagram of Scalesia forest in Plot Fl. Keys to abbreviations: Cr, Croton scoulerii Ct, Citrus sp.; Dw, Darviniothamnus tcnuifolius; L, Lantana catnara; Pi, Psidium guajava; S, Scalesia Trcdunculata. south-west direction from which the prevailing are also having serious negative impact on the wind frequently carries moisture. Many intro- native vegetation. duced plants have become wild and invaded Sca- lesia forests around Cerro Pajas. For example, (2) Scalesia pedunculata forest (Outside the Psidium guajava, Citras spp., Lantana camara, crater) and Kalanchoe pinnata are very common on the Scalesia pedunculata, which is common to plateau area. Feral cows, donkeys, goats and pigs Santa Ctuz, makes a dense forest around Cerro 94 Competitive Relationships between Tree Species of Scales ia and Introduced Plants (Shimizu) ハ ワ 『 賓 ⊃ ０ ５ 】 Ｑ 乙 』 〇 “ 嬢 Ч ら ２ 6-9 9-12 12-15 □ DBH CLASS (cm) 圏 ■l s(dead) 1田 cr 剛 Others ｈ 〉 〔 コく⊃ ∩】 ＞ ＯＺ一一 」 〇 に 国 ∞ Σ⊃ Ｚ 6-9 9-12 12-15 □ DBH CLASS (cm) 圏 ■l s(dead) |■ cr 硼 others ＜ ｃ 唆 マ ２ ０ ８ 〓 ２ １ ５ ‐ ０ ６ 蚤 ５ 聟 ヲ ０ 3-6 6-9 9-12 □ 脚 DBH CLASS (cm) S 圏 cr 圏Pj others ■ dead “ ヽ PLOT F4 路で⊃ ∩ 】 ≧〔 乙」 〇配 国 ｍ Σ⊃ Ｚ Fig. 124. DBH histograms of Scalesia forests with the invasion of Psidium in Plots Fl, F2, F3 and F4. Keys to abbreviations: Cr, Croton 3-6 6-9 9-12 scoulerii Pj, Psidium guajava; DBH cLASS (cm) S, Scc lesia pedun- culata. □ S tt Pj I dead Pajas, especially on the windward slope (plots seedlings of Scalesia were found in the plot. F1-4). Plot Fl is located on a rough exposed lava croton scouleri, cordia leucophlyctis, Zanthoxy- (Fig. 122, Fig. 123). The canopy, 5-6 m high, is lum fagara and introduced species such as psi- exclusively dominated by scalesia. Most of the dium guajava and Citrus sp. appear in the T2- canopy trees have thin stems and small crowns. layer sparsely. Darwiniothamnus tenuifolius and Some of the thin stems are dead (Fig. I24a). Lantana camara are abundant in the shrub-layer. Though the canopy is nearly closed, it is bright in The Herb-layer is very poor in species composi- the forest because the amount of leaves of scale- tion and coverage. Though the ground seems to srd crowns is not so much. Even so, no saplings or be dry, moss and lichen occur to some extent on ―- 95 -― Regional Views No. 11 1997 Tl:O T2:o S:x 10mX10m ヽ ． ． ‐ ， 了′ 、 ＼ 、 略 、 ‥ ′ ′ 一 一 Ffg. 125. Crown projection diagran of Plot F2 showing the invasion of hidium in t Sulosia forect. Keys to abbreviatione Cl, Clerdendrum mollc; Co, Corilia andaoniii Cr, Crotan scoulerii Ca' Citrus slt.i L' Iantaru camam, Pj, hidium guqiavai S, Scalesia peduncuhb, Zl, lanthoxylum fagara. S Fig.126. Profile diagren of Plot F2 rhowing the invasion ol hidium in the ScaLafio foreot. Keys to abbreviations: A, Cbrorlcnilrtm moll4 Ct, Crotan scouleri; Ct, Citras sp.; Kln, Kalanche pinnataS la Lantatu camana, P!, Psidium guqiava; S, Scalesia pduncuhta. the exposed lava rocks. Trachypteris pinnata Plot F2 is located on a flat place just below Plot grows frequently on the rocks. A patasitic plant, Fl. Only two Scalesia trees, 6 m high, are left in Phoradendron henslovii (common to Site D), is the plot, while small trees of Psidium guaiava,3- found on the branches of Scalesia. 4 m high, cover the T2-layer densely (Fig. 124b, 96 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) 10mX10m Fig.127. projection Crown diagran ol Scatesia forest in Plot F3. Keys to abbreviations: C-n, Cordia leucophllctis; Cr, Crctnn scoulcr\ Ct, Citrus sp.; I)w, Darviniothamnus tznuifolius; M, Macraea taficifolia3 Pf, Pisonia floribunilai 4, hiilium guajava\ s, scalcsia @uncul.ata; zt, zaihoxytum fagara. Fig. 125, Fig. 126). Four dead scalesia trees ground among which black soil is thinly dis- found in the plot must have been shaded out by tributed. The DBH histogram has a clear mode the invasion of Psidium guajava. Kalanchoe pin- between 6 cm and 9 cm (Fig. l}4d). The largest nata, 0.5-1 m high, covers the ground so densely tree of Scalesia is 8 m high and 14.5 cm DBH. that establishment of tree seedlings should be very Each individual has a straight stem up to 5 m high difficult. Kalanchoe produced many flowers at the and spreads branches upward. Most of the thin time of study (Photo lz). There are several trees of scalesia are dead due to self-thinning. donkey-tracks running through the plot. shrubs The canopy is fully closed, though crowns of of Lantana psidium camara and saplings of gua- Scalesia never overlap with each other (Fig. l}g). java are abundant in the Shrub-layer here, too. Crown size is varied from small to large. The TZ- plot g'lo" g0o F3 ( 1" l s, 27, ll,,w, Alt 330 m) layer is vacant and the shrub-layer is also poor. is located on an exposed lava. The structure and Psidium guajava and Lantana camara ate not so the species composition of the scalesia forest in many in the plot. small trees of croton scouleri, Plot plot F3 are nearly the same as those of Fl. some of which are dead, are found frequently in But could I find a few young trees, saplings and the shrub-layer. Macraea laricifolia makes a few seedlings of scalesia in the plot (Fig. rz4c). This clumps in the plot. The coverage of the Herb- is because the canopy is not fully closed and the layer is also small. invasion of Psidium and Lantana has not pro- ceeded so much (Fig. 127). (3) Scalesia pedunculata plot forest (Inside the 4 (1" 1g'22"5, gO"27'20"'W, Alt. 340 m) crater) is a developed Scalesia forest, 8 m high, on a flat There is a small world inside the old crater of place (Fig. 128). Lava rocks slightly covered Cerro Pajas. Only the SSW part of the round with moss are exposed here and there on the ridge is cut open by a small valley. As the valley 97 Regional Views No. 11 1997 Fig. 12t. Proflle diagran ol Scalxia forest in Plot F4. Keys to abbrevirrtiong: Cr, Crobn scoulerii L, Lantana aamam, M, Mauau laricifoliai P!, Psi.ilium guajavaT S, Scalesia pdunculata. Underlined symbols show derd hees. 10mX10m crx ----o,s '... _ - -_y-:,; -'-ir'.l , Ftg. 129. Crown projectioa dlegrln ol Scalesia forest in Plot F4. Keys to abbrevirtions: Cr, Crcbn scouWii Co, Cordia teucophllctis; M, Macmu laficifolia; Pi, Psidium guajava3 S, Scalesiu pdunculan. Underlined gymbolg shor derd hees. collects moisture from the prevailing south wind, plot F5 ( 1" I 8' 14' '5, 90" 27'28 "'W, Alt. 3 80 m) it is moister than other places outside of the is located on the lower part of the slope (Aspect: crater. A Scalesia pedunculata forest in a rather SSW, Inclination: 22" ). The habitat is moist. natural condition covers the whole slope and the The canopy is composed of large trees of Scalesia valley bottom of this place (Photo 13). (Fig. 130), all of which have a DBH more than 9 98 Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu) 10mX10m Fig. 130. Crovn projection diagran of Scalsia forect in Plot F5. Keyc to abbrevirtions: Cr, Cmton scouleriT Co, Cordia leucophlyctisT Pi, Pl;itlium gaajaw; S, Scalesia pcilanculata. PLOT F5 Fig. 131. DBH histogram of Scalesia forest in 6-9 9-r2 r2-r5 15-18 18-21 21-24 Plot F5. Keys to abbreviatiorun Cr, Croton DBH cLASS (cm) □ 硼 scoulerii Pj, Psidium guajava; S, Scclesia pedun- S 囲Pj ICr culata. others I dead cm (Fig. 131). The largest individual is 6 m high cies, covers its crown. It produced many matured and 2l cm DBH. Only a few saplings and seed- fruit at the time of this study. lings of Scalesia are found in the plot. Croton A Scalesrc scrub, 3 m high, mixed with Croton scouleri is rather abundant in the Shrub-layer. scouleri appears on the upper part of the slope Psidium guajava is invading the forest. Small (Alt. 430 m; Plot Fl2) (Fig. 132). Mauaea trees of Psidium have established in the T2-layer. laricifolia and Ctenitis sloanei make clumps here The soil layer is thin. Moss covers the surface of and there in the Shrub-layer and the Herb-layer, exposed lava rocks. Asplenium formosa grows respectively. Psidium guajava and Lantana frequently on the rocks. Ctenitis sloanei is sparse- camara have also been invading the scrub, though ly distributed. Psychotria angustata, the endemic the frequency is still low. Juveniles of dark- shrub in this area, is found in the Shrublayer. rumped petrel (Pterodroma phaeopygia: a kind of There is a big tree of Pisonia floribunda near the sea bird which nests in moist highlands at the time plot. Passtflora edulis, a very invasive vine spe- of reproduction) live in hollows under exposed ―- 99 -― Regional Views No. 11 1997 Fig. 132. Profile diagram of Scalesia-Croton mixed scrub in Plot Fl2. Keys to abbreviations: Cr, Croton scoulerii Co, Cordia leucophlyctisi L, Lantana camara; M, Macraea laricifolia; Pi, Psidium guajavai S, Scalesia pedunculata. Fig. 133. Profle diagram ot Scalzr;ia forect in Plot F7 with the invasion ol Citrus. Keyc to abbrevirtionr: Ct Citrus litrlcttai S, Scalelri4 pdarcuhtai Tf, Tournefortia pulrscens1 Zl, Tantlnxylum fagara. basal rocks on this slope. National Park Services Plot F7 is a Scalesia-Citrus mixed forest with a has been recording reproduction of the petrel fully-closed canopy (Fig. 133). The canopy layer, since 1987 and doing a project to eradicate rats 9 m high, is composed of large trees of Scalesia, which feed on eggs of the bird. most of which have thick stems more than 10 cm - 100- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) in DBH. The stems are straight up to +-S m high, Scalesia are growing in the canopy gap with the which is comparable to the height of saplings area of about 30 sq. m. The highest sapling found in Plot F10 mentioned later. Citrus sp.(a attains to 2.35 m, while most of them remain less kind of lemon) , dn introduced tree, makes the than 0.5 m high (Fig. 136). This means that the dense T}-layer, 4-5 m high. It takes a multi- regeneration occurred within one year. Psidium stemmed growth form. As it is dark on the guajava is also invading the gap. The largest one ground, the Herb-layer is nearly vacant. A few is 3 .2 m high, but it must be older than Scalesia saplings of Psidium guajava occur in the forest, saplings. In contrast to the Scalesia saplings, but they are dead or nearly dead. Psidium saplings include individuals with a varie- ty of sizes (Fig. 136). Plumbago scandens spreads (4) Gap regeneration of Scalesra forest to make large clumps over the ground. Large trees of Scalesia (9 m high, 20 cm ( Plot F10 is a belt-transect which was put DBH) make a forest with closed canopy at the through an older canopy gap in the same Scalesia flat bottom of the valley in the crater. There are forest. A dead fallen tree of Scalesia (L4.8 cm in relatively new fallen trees of Scalesia, making diameter) and seven fallen trees of Croton (six of canopy gaps here and there. As the root system them are still alive) are found on the ground in of Scalesla is shallow (weak ?), large trees with a the canopy gap (Fig. 137). Seven Scalesia sap- heavy crown seem to collapse easily by occasional lings, 3-5.8 cm DBH, grow up to 4-5 m high in strong wind. Plot F6 shows the regeneration of the gap. They are all vigorous. Stems are strai- Scalesia saplings in a canopy gap (Fig. 134, Fig. ght. But no saplings and seedlings smaller than 135). A large Scalesia tree (21 cm in diameter)is those are found even though the gap is still open. lying up-rooted on the ground, though it still has The gap seems to have been made about two years living leaves. Many saplings and seedlings of ago. Psidium guajava is invading the gap, too. dead : Sap I i ng: o s ｀oc",,j 5 ｀~‐ S メ ・ ・ ｀＼ ′ °Ч (1年 γ°。cふ ブ｀、_ノ｀、、 「 'ア △ _ S 口 Δ ll s▲ Fig. 134. Crown projection diagram of Plot F6 showing the regeneration of Scalesia in I canopy gap. Keys to abbreviations: Cr, Croton scouleri; Pf, Pisonia fl.oribunda; Pj, Psidium guajava; S, Sca lesia pedunculata; Tf, Tournefortia pubescens. ―-101-一 Regional Views No. I I lggT F19.135. Profle diagrem of Plot F6 ehowing the regeneretion of Scalasia in a canopy glD. tre1,3 to abbrevirtions: 6, Croton scoulcrl Pl, Pisonfu fuiburulal P!, hidium guajoyai Plb, Plambago scandens; S, Scdesia pdurcahtai Tl., Tournefortit pufuccns. ８ ８ ０ ≦ Ｑ 后 ｚ ｂ ２ ０ 蟹 冒⊃ Ю ｚ ０ Fig. 136. Height histogram of seedlings and 0。 1-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 saplings in the canopy in Plot F6. Keys to HEIGHT CLASS (m) abbreviations: Pj, Psidium guajavai S, Scalesia □ s tt Pj pedunculata. T1 : o T2:o S: x dead: r Ft8. 137. Crowa projecdon diagram of Plot F10 rrhowing the regeneration ol Scalrrifu in a canopy gap. Keys to abbreviadons: Co, Cordia leucophlyctig &, Croton soulefiS Cq Cit'rlts gp.; Pf, Pisonia floribundaT p!, Psidilrm guoiawi S, Scal.aia @unculataT Tl, Tournefortia pubacens. (5) Invasion of Lantana camara scrubs, 3-4 m high, oD the dry upper part of the Scalesia forests change to Croton dominant slope at the outside of the crater. Plot Fl l shows -102- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimi"u) Ftg. 13E. hoffle diagran of Plot Fll ohowing the hansition l part betreen Scalcsia forest (lower) rnd Crobn-I'antana rcrub (upper). Keye to abbrevlations: h, Corilia leucaphbaisi &, Crtun scoulefi; L, Lantana camami M, Macmea l.aricifolia; W, Pisonia floribunda; Pl, hidium guojava3 S, Scalxia pedunculatai TI, Tournefortia puhcens; Zf, Zantlwxylum fagara. the transitional part between them (Fig. 138). them producing fruit) and ten saplings (0.9-3.3 The situation is similar to that found in Site D m high) of Scalesia occur in an open space along (Plot D17) though the Croton dominant forest is a path (Fig. 142). This is a kind of gap regener- located below the Sca lesia forest in Site D. In ation of Scalesia. The other part of the plot is addition to Croton, the scrub is composed of covered densely with many large clumps of Lan- M acraea laricifolia, Cordia leudophryctis, Cleroden- tana camara. Each Lantana individual has one or drum mole, Lantana camara and so on. Macraea two thick dead stems and many thinner living and Lantana continue to appear in the Shrub- sprouts and branches (Fig. 143). The histogram layer of the Scalesia forest at the lower part of the of stem diameter class for the thickest branch in slope. each individual shows a clear peak at the 3-4 cm On the arid leeward side of the mountain, small class (Fig. 144). There are some small individ- patches of Scalesra forest are scattered in a dense uals of Lantana, but no seedlings of Lantana Lre thicket of Lantana camara (Plot F8)(Photo 14). found in the plot, even though most of the large Scalesia trees, 5 m high, make a loose canopy individuals bear much fruit. Lantana shed almost (Fig. 139, Fig. 140). Four individuals of Scalesia all leaves at the time of study, maybe because of are dead (Fig. 141) and the amount of leaves in the arid condition in the dry season. However, each crown is not so much even on living trees. they would have many leaves in the moist season No Sca lesia saplings and seedlings are found in and shade out seedlings of Scalesia and of their the forest. The T2-layer is almost vacant. Large own. It seems that the Lantana thicket estab- clumps of Lantana camara cover the Shrub-layer, lished all at once in the past, and it has been 2-3 m high, together with some shrubs of Mac- reproducing by repeated sprouting. raea laricifolia, Tournefortia pubescens, Cleroden- There is a large tree of Geoffraea spinosa near drum mole and Chiococca alba. They are so dense the plot. This introduced tree makes a large that it is very difficult to pass through the plot. crown sporadically in this area. It produces many The relative light intensity is 24.lVo on the large fruit, which feral donkeys and pigs eat and ground. The Herb-layer is very poor. Seedlings disperse seeds here and there. I sometimes found of Lantana camara are also rare in the forest. a mass of seeds in droppings of these animals on Plot F9 is located near Plot F8. One adult tree the ground. growing just outside of the plot (the supposed original seed source), three young trees (two of -103す Regional Views No. 11 1997 T1 :O T2:@ S:x dead:.,7 10mXlom Fig. 139. Ctrown projection diagrrm of Plot Ft choring the invssion ol Lantana in the Scaferic forest. Keyc to abbreviations t A, CbroMrum motlq G, Crotan saulerii L, La ntuna can ara; M, Macraoa larbiloliti S, Scalaia padunculata. FiS. l{O. Proffle diagram of Plot Ft choving the invasion of Lantuna in the Scalasia forect. Keyc to abbrevlrtiono: G, Crobn rcoubri la Lantana saman i M, Macraea laricitoliai Pl, Psidium gt4iawT S, Scalaia pduruulata. - 104- Competitive Relationships between Tree Species of Sco/es ia and Introduced Plants (Shimizu) 碧 PLOT F8 ‥ｂ 言 0-3 3-6 6-9 ＜ 9-12 12-15 DBH CLASS ｃｍ □ 鯰 ■剛 Fig. l41^. DBH histogram of Plot F8. Keys to S(dead) abbreviations: Cr, Croton scoulerii S, Scalesia other pedunculata. 丁2:o S:x 10mX10m 一 L ヽ LX I 】 Ｌ X｀ 、 ノ 「 Ｘ 社 イ、 t、 お ゝ｀‐・。_}ト‐ ｀ 】． (‐ 手 ヽ、、 ｀ ｀｀ ｀ ″t｀ ‐ ノ ヽ ∫ _も ._´ ′ | ト |:: : ′ ゝヽ、 4 _。 _′ [ a .)*'a'-a ´~ i Lx ´~″ 二 メ lr,- .´ て L / ! ,' ' XL 'ft. rrrr ..'rJ'--"'- t'\. _ _ _ -_r, L -,, >, tヽ ts"- -- -i" i L : _― 卜.‐ . ..----\. tatf I ,' ／ ヽ ＼ ｒ ".r, シ ‐‥1., '..\-.. -,-.-r.1 . .. Ｓ ， Ｌ 二 :lx,i-'. 、 ‐‐ \: co,'i xL ぃ 'r1 i. ‐ Ｈ tl ‐ 」 Y :; ' -.r'i:""'.. " "('.. .." tt ---.;---'t\_ _二 i-,r 'tt i 、_´た ".' ……‐ヽ 。 Lx 1"t.. , i 社 ″ 、、‐‐」 、′″f t \t'--.-ii l'f ,i ..-- 'cLx -,'- Lゝ LX/1 i ^ \. t'x | = \rl X｀ ヽ 、 メ '. ,' x _、 ...- il I 、 _:′ j Lr ・恥 ギ、_.. .; i Fig. 142. Crown projection diagram of Plot F9 showing the regeneration of Scalesia along a path in the Lantana dominant scrub. Keys to abbreviations: Cl, Clerodendrum molle; Cr, Croton scouleri; L, Lantana camarai S, Scclesia pedunculata. 7. Scalesia afi,nis scrub Black Beach to Alcedo (Site E) in Isabela, and ( 1) Location Site FL: from Puerto Velasco Ibarra to Cerro A shrubby Scalesia, S. ffinis, occurs in the Pajas (Site F) in Floreana (see Fig. 4). Arid zone in some big islands. I surveyed the ecology of S. afinis in the four sites which are (2) Santa Cruz: Site SC located on the way from the coasts to the study I observed the Arid zone vegetation of the sites of Scalesia forests; Site SC: from Puerto windward slope of Santa Cruz: ( 1) around Ayora to Bella Vista (to Site A and B) in Santa CDRS, (2) on the way from Puerto Ayora to Cruz, Site IBa: from Puerto Villamil to Santo Tortuga Bay, and (3)along the road from Puerto Tom6s (to Site C and D) and Site IBb: from Ayora to Vella Vista. The Arid zone is composed -105- Regional Views No。 11 1997 Fig. 143. Profile diagram of Plot F!) showing the regeneration of Scalesia along a path in the Lantana dominant scrub. Keys to abbreviations: L, Lantana catnara; S, Scalesia pedunculata. 路 ５ ０ 颯 Ｚ ８ 日 目２ Fig. l44.. Diameter histogram of Lantana 1-2 2-3 3-4 4-5 5-6 camara in Plot tr9. Diameter of the thickest stem DIAMETER CLASS (cm) in each individual was measured at the height of □ alive l■ dead 0.2 m. of many tree and shrub species adapted to arid 146). Bursera has several saplings around the conditions such as Bursera glaveolens (palos- parent tree. Only one individual of S. affinis, 2.5 anto), Parkinsonia aculeata, Scutia pauciflora, m high, is found in the plot. It has a multi- Castera galapageia, Opuntia echios var. echios, stemmed growth form (max. 5.2 cm DBH). No Jasminocereus thouarsii var. delicatus, Croton scou- seedlings and saplings of Scalesia are found, even leri, Cordia lutea, Acasia roradiana, A. macra- though the canopy is not closed. I could barely cantha, Altenanthera filifolia, A. echinocephara, find another individual of S. affinis near the plot, Chiococca alba, Clerodendrum molle, Prosopis but no more in this area. Both endemic and jultflora, Gossypium barbadense, Tournefortia introduced species of Lantana (L. peduncularis rufoserice a, T. pub e sc en s and Z anthoxy lum fagara. and L. camara) occur together in the plot. This No one species becomes dominant, though the would be a problem in preserving the endemic ratio of the component species changes from species if interbreeding is occurring between place to place. The canopy is usually not closed. them. The ground mostly made of exposed lava Bare lava rocks are widely exposed on the ground. rocks is rough and dry. The Herb-layer is poor. I searched for Scalesia afinis in the three places It is composed of .Blainvillea dichotoma, Rhyncho- mentioned above, but I could find it only in an sia minima, Boehaavia erecta, Commicarpus tube- arid scrub near the road in the suburbs of Puerto rosus, Mentzelia aspera, Porophyllum ruderale and Ayora (Plot SCl: Alt. 10 m). There is a big tree so on. of Bursera graveolens,5.5 m high, in the Tl-layer Scalesia pedunculata appears at the altitude of of the plot (Fig. 145). A variety of trees and 120 m and above on the way from Puerto Ayora shrubs make the T2- and the Shrub layers (Fig. to Bella Vista. I could not find any Scalesia trees 一-106-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Fig. 145. Profile diagram of Arid-zone vegetation with Scalesia afinis in Plot SCl. Keys to abbreviations: Br, Burxera graveolens; Ch, Chiococca alba; Co, Cordia andesonii; Lc, Lantana camarai Lp, Lantana peduncularis; op, opuntia echios v. gigantea; S, Scalesia afinis; St, Scutia pauciflora; Zf, Zanthoxylum fagara. T1: O T2:@ 10mX10m Fig. 14'6. Crown proJection diagran of Arid-mne vegetadon vlth Scalosia afizis in Plot SCl. Keyr to abbrevia. tions: Br' Bursera graveolensl 6, Cordia andaonii; Lc, Lantana camarai I.p, Lantona @uncultrisi Op, Opantia cchiu t. gigantea: S, Scalsria cjizfu; Sl Scuti.a pucifora1 Zl, Zanthoxylum fagtm. -to7- Regional Views No. I I 1997 (both S. affinrs and S. pedunculata) at the altitude on a windy, exposed slope at the low altitude (Alt. between 10 m (Plot SCI) and tZO m (Bella 50m) (Photo 15). The scrub is composed of Vista). The distribution of the two Scalesia spe- Altenathera filiformis, Camaesyce punctulata, cies does not overlap with each other along the Dodonaea viscosa, Macraea laricifolia, Scalesia altitudinal gradient. I could neither find S. affinis affinis, Sarcostemma angustissima and Walteria in the arid vegetation around CDRS nor on the ovata. Some of them including Scalesia have way to Tortuga Buy, though these places seem to seedlings in the plot (Fig. 150a). Almost all be good habitats for ,S. affinis (I might have individuals are less than 1 m high and take a overlooked it, but even so it must be very rare). wind-shaped growth form because of the strong Unknown events in the past rather than present prevailing wind. Aristida divulsa occurs sparsely conditions may be related to the lack (or rare- on the ground which is made of thick pumice ness) of S. affinis in these places. accumulation. Most of the individuals were dead at the time of survey. (3) Isabela: Site IBa (San Vicente) A small tree of Bursera glaveolens, 3.5 m high, A vast lowland area on the windward side of appears in the arid scrub in Plot IBb2 (Alt. 100 Sierra Negra, Isabela, is covered with arid vegeta- m). It is interesting that eight shrubby species tion whose component species are nearly common (Scalesia affinis, Scutia pauciflora, Chamaesyce to those of Santa Cruz. Plot IBal (0'56713"5, punctulata, Cordia revoluta, Sarcostema angus- 90o59'19"W, Alt. 5 m) was put in the arid vege- tata, Lantana peduncularis, Yallesia galbra and tation with Scalesia afinis shrubs. The habitat is Castera galapageia) make a clump of crowns completely made of bare lava. Several Bursera around the Bursera tree (Fig. 150b). Two S. graveolens trees, 4-6 m high, make patches of affinis individuals (0.6 m and 0.9 m high) are canopy (Fig. 147). Croton scoulerf and S. affinis found in the plot. Chamaesyce viminea and C. appear in the T2-layer,2-3.5 m high. The Shrub- punctulata are frequently distributed. Aristida layer is composed of many clumps of Chamaecyce divulsa occurs sparsely on the ground. viminea and some other shrubby species (Fig. Many S. affinis individuals are distributed in 148). Two individuals of S. afinis have a multi- Plot IBb3 (Alt. l50m) (Fig. 151). A variety of stemmed growth form with 7 and 14 stems per developmental stages are included in the plot individual, respectively. Only a few herbs such as (Fig. I52a). The regeneration of S. affinis seems Mentzelia aspera, Plumbago scandens and Passi- to be successful here. A mature individual of S. flora foetida grow on the dry and hot ground. affinis takes a multi-stemmed and procumbent Plot lBa} is adjacent to Plot IBal. It was put growth form. It spreads branches to all direc- in a flat place which had once been bulldozed tions, forming a semi-spherical crown. But it before 1980. Plants have invaded the place again easily collapses with the increase of leaves on from surrounding vegetation. No Bzrsera tree is branches and dies, so the large crown above the in the plot. Several shrubby species make small ground does not last long. I found many collaps- clumps here and there. Six saplings of S. affinis ing individuals some of which were nearly dead (0.3-1.9 m high) are found and one of them is (Photo 16). I also found that a small individual, dead (Fig. 149). It is characteristic that Darutini- 0.43 m high, had flower buds. It is characteristic othamnus tenuifoius occurs frequently on the bare that old dead leaves do not drop for several years, lava. These two species both of which belong to covering stems densely. The beetle which I found endemic genera of Compositae are pioneers in in the trunk of S. cordata in Site D was found in this habitat. The Herb-layer is very poor. the stem of S. affinis here. According to Mr. Gordillo's observation, S. Plot IBb4 (Alt. 190 m) is located near the affinis occurs up to 50 m in altitude and S. cordata upper limit of the S. affinis distribution. Ten begins to appear at the altitude of 75 m, so there individuals of S. affinis (one is dead) grow in a is no Sca lesia between the two elevations. The Bursera sparse forest on the sunny and windy distribution of the two Scalesia species do not south-facing slope (FiS. 153, Fig. 154). ,S. affinis overlap here, either. has individuals with a variety of sizes except seedlings in the plot (Fig. l52b). But I did not (4) Isabela: Site IBb (Alcedo) find any S. affinrs individuals in the same type of Scalesia affinis appears from the coast to the forest around the plot. Many clumps of Macraea altitude of 210 m on the north east slope of laricifolia and Walteria ovata are distributed in Alcedo (Site E). Plot IBbl shows a dwarf scrub the plot. The situation is similar to the Scalesia -108- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Fig. lg. Proflle diagran of Arid-zone vegetation vilft-ftalrr;io afinis in Plot lbal. Keys to abbreviations: Bt, Burscra gtaveolens; G, Ctdan scouler\ Ct, Chamesyce vimhuti, Dv, Darwiniotlumnus Enuifoliuq Og, Opuntia uhios t. incrmis; S, Scalasia afinis. 10mX10m Fig. 148. Crown projection diagran of Arid.zone vegetation with Scclesia afinis ia Plot IBal. Keys to abbreviationc: Bt, Bursera gmveolrzr;S &, Croton scoulcr\ Cr., Chamesyce viminea; Dv, Darwiniathamnus bnuifolius; Op, Opuntia thi.os t. incrmis; S, Scolan:a afrnisi St, Scutia paaciflotu3 Tl, Tounulortia psilostachya. -109- Regional Views No. 11 1997 丁2:o S: x 10mX1 0m aca2--t:a x.s tt------ Fig.149. Crora projection diegren of Plot IBa2 showing the regeneration of Arid. zone vegetation on a bare bva. Keyr to abbrevirrffonr: C4 Capraria peruvianal Dv, Darviniothamnus tcnuifolius; S, Sca;esia afinis; Tf, Tournefortia pilostachya. PLOT IBbl *--v(ind Do PLOT IBb2 Fig. 150. Proflle diagrems of Arid-zone yegetation with Scalecia afinis in Plotc IBbl gnd IBb2. Xeyr to abbreviations: Ats' Aristidt tlivalsa; Bt, Bunera gmvulcns; Cr., Chanusyce vimircai Do, Ddonau viscosa; S, Scalrsia a1fllnis; St, Scutia puciflom3 Sr, Satxoshma angustissima; Ya, Vallaia galbm. - 110- Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu) T2:s S:x 10mX10m Fig. 151. Crown projection diagran of Arid-zone vegetation with Scalesia afinis in Plot IBb3. Keys abbrevirtions: Br, Burtem graveolens; M, Macraea laricifulia3 s, scalesia afinis7 w, waltpria ovata. ＜ ａ ＞ PLOT IBb3 ∽ 冒 ‐ ４ 昌 ‐ ２ 買 ‐ ０ ２ｂ ８ ６ 饉 ４ ロ ２ ヲ ０ 0-0。 2 0.2-0.4 0.4-0.6 0.6-0「 百 0.8-1.0 1.o-1.2 llEIGHT CLASS(0 □ s.affinis Φ Ｆ 一 Ｒ 冒 ９ ｂ】 国 冒 ヲ 0-0。 2 0.2-0.4 0.4-0.6 0.6-0.8 0.8-「 0 1.o― ゴ両 HEIGHT CLASS (m) Fig。 152. Height hお tOgrams of scaJgsjα q"πお □ s.affinis in Plots IBb3 and IBb4. ―-111-― Regional Views No. 11 1997 T2:@ S: x 10mX10m Fig. 153. Crown Drojectlon diagran of Burrera foregt with Scalqia afinis in Plot IBM. Keys to abbreviations: Br, Buncm gruveolerti M, Macraea laricifolia; S, Scalesia afrnhi W, llalhtia ovata. Fig. 154. Profile rtiagram ol Bunem forest with Scatrr;ia afinis in Plot IBlr4. Keys to ebbrevietionc: Br' Buncra gaveolensiM, Macmu hricifolia; S, Scal.aia afinisl Vl,lfaltzria ovata' - 112- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shim izu) microcephala forest (Plot E1-3) at the upper alti- not only to elevation but also inclination of slopes tude. Saplings of Bursera are also growing and edaphic condition. A spinous scrub, 4-6 m around adult trees. Aristida divulsa, less than 0.2 high, dominated by Parkinsonia aculeata and pro- m high, covers 4ovo of the ground which is made sopis juliflora continues to occur from the coast to of thick pumice accumulation. the altitude of 110 m. It is difficult to pass thr- As mentioned previously, no Scalesia (neither ough the dense coverage of spinous trees in this s. affinrs nor s. microcephala) occurs between 2r0 zone. Bursera forest appears at the altitude be- m and 350 m in altitude. The two species never tween 110 m and 26o m. This zone is divided into overlap with each other in this region, either. It two parts. The lower part ( I 10 m-190 m) is a tall seems that s. microcephala needs moisture, while Bursera forest, 7-8 m high. The species composi- ,S. ffinis needs wide, open ground made of bare tion is mostly common to the upper part, but the lava pumice or accumulation for its establish- amount of herb and grass on the ground is less, ment. and lichen hung on the crowns is scarce because of the arid condition. On the other hand, the (5) Floreana: Site FL upper part ( 190 m-260 m) is a low Bursera forest, I observed the altitudinal change of vegetation 6-7 m high. The Shrub layer is composed of on two slopes of Floreana: (a) west-facing slope Clerodendrum mole, Prosopis juliflora, Castera puerto from cerro Pajas to the coast of velasco galapageia, Cordia leucophlyctis, Tournefortia psy- Ibarra ( 1" 1 7'm' '5, 90" 29'zg' ') and (b) north_ lostachya, Pisonia floribunda, Vallesia galbra, and facing slope from cerro Pajas to the coast of post Zanthoxylum fagara. Lichen with white color office Bay (1" 14'3g"S, 90"27'07',w)) (see Fig. (Usnea sp.) is frequently hanging on the crowns. I2l). Blainvillea dichotoma covers the ground densely. The vegetation of the west-facing slope is divid- A dry scrub with sparse distribution of Mac- ed into three zones except a coast al zone. ( 1) raea laricifolia, Lantana camara, Walteria ovata, Lowland area less than 100 m in altitude is cov- and Prosopis juliflora appears on a rocky steep ered with a Bursera forest, 7-8 m high, associated slope at the altitude between 260 m and 330 m. with woody species such as clerodendrum mole, similar scrubs occur on arid rocky slopes at lower parkinsonia scutia pauciflora, Prosopis juliflora, elevations, too. A low forest, 4 m high, dominat- aculeata, castera galapageia, cordia leucophlyctis, ed by croton scouleri and Psidium guajava dense- Gossypium barbadense var. danvinii, vallesia ly covers the flat area on the plateau at the galbra and capraria bffiora. The lower part of altitude of 330 m. clerodendrum mole, pisonia this zone (up to 50 m in altitude) has been ex- floribunda, Cordia leucophlyctis, Zanthoxylum ploited for cattle fields and residence area . (Z) fagara are main component species. Citrus sp. Bursera sparse forest, 5-6 m high, appears at the invaded the forest and Geoffraea spinosa makes a middle part of the slope (Alt. l,ZV250 m) with large crown here and there in the forest. Kalan- species common to the lowland forest and some choe pinnata is dominant on the ground. No other species such as Macraea laricifolia, croton Scalesia trees are found in this forest. scouleri, Zanthoxylum fagara, Pisonia floribunda, Psidium guajava disappears on this slope at the cordia andesonii, Tournefortia leucostachyus and altitude lower than 300 m. Lantana camara also walteria ovata. (3) scalesia pedunculata forest occurs only at the upper par1" of the slope, 200 m occurs at the altitude of 290 m and above, but and above in altitude, but instead, Lantana ped- most of the area has become a secondary bush unculata (native sp.) appears in the lower part of with croton scouleri and Lantana camara. These the slope at the altitude lower than 180 m. so the zones (three types of forests) are connected with distribution of the two Lantana species does not each other with a narrow transitional zone ( l0o- overlap in altitude. This situation is different l2o and m 25v280 m). It is noteworthy that from that in Santa craz (Plot scl) where both introduced species of Lantana camara, psidium Lantana species are growing together. guajava and Kalanchoe pinnata grow well only at It is noteworthy that a kind of endemic Compo- the altitude above 2so m. I did not find these sitae, Lecocafpus pinnatifidus, occurs on a bare species below 200 m. Their occurrence must be lava near the coast in both the north-facing and related to moisture of the habitat. the west-facing slopes of the island. plot FL I The arangement of vegetation on the north- shows one of the habitats of Lecocarpus on a bare facing slope is more complicated than the west- lava near the town of Puerto vellasco lbarra. It facing slope (see Fig. l2l). It seems to be related is located about 500 m inland from the coast line. ―H3- Regional Views No. l l 1997 T1 :9 T2:s S:x 10mX10m Fig. 155. Crorn projection diagram of Bursera forest with Scalesit afinis in Plot FLl. Keye to abbrevla- tions: Br, Bunem gmvalensi Ct, Chamaaycc viminui J\ fasmirmcereus tlnuanii t. tlnaani\ Le, I*cuarpus pinnatifrilusi S, Scclesia afinis7 Tl, Tournefortia psilostachyai W, Waltzria ovata. Fig. 156. Proffle diagram ol Bursem forest with Scal.aia afinis in Plot FLl. Keyr to rbbreviations: Br' Bunera gaveolenq Jt, lasminucnus tlnuarsii v. tlnuanii; Le, Lamrpus pinnatifidus; Rhy, Rhynchuia minina; S, Scalesic afinis;Tf, Tournefoftia psilntoahya. I could find Scalesia afinis only here in Floreana. crown in the plot (Fig. 155, Fig. 156). The The plot is at the lower limit of the Bursera forest. canopy is not closed. Saplings of Bursera are also One large tree of Bursera, 6 m high, has a large found. Six individuals (0.45-1.8 m high) of S. - 114- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) affinis are growing in the plot. The regeneration ious sizes died just after the El Nifio event in his of S. ffinis seems to be successful. Jasminocereus permanent quadrats in Santa Cruz, though Psi- thouarsii var. thouarsii, Lecocarpus pinnatifidus, dium galapageium, Pisonia floribunda, and Zan- Tournefortia leucostacys, Walteria ovata and Cha- thoxylum fagara were not killed at that time. He maesyce viminea are other associates. Rhynchosia speculated that the recovery might start after the minima covers the bare lava to some extent. next dry season in Los Gemelos, but abundant ,S. pedunculata and S. affinis do not overlap vines (Stictocardia tilliifolia, Passiflora col- with each other in the altitudinal distribution in invauxii) covering the tree and shrub layers Floreana, either. would retard the recovery in Caseta. Itow & Mueller-Dombois ( 1988) found a recovering IV. Discussion young cohort and some remnant trees left after the synchronous collapse at Los Gemelos (Site B 1. Regeneration mechanism of Scalesia forest in this study) in 1987. De Vries & Tupiza (1990) Success of the invasion of introduced plants recorded a new cohort and some old trees of S. into Scalesia forests depends on relationships cordata in Alemania (Site C in this study) after among environments (location, geology & geog- the 1982-83 El Nifio event. raphy, climate, disturbances, etc.) , characteristics On the other hand, tree Scalesia makes a sparse of Scalesia forests (species composition, forest forest with a broken canopy in dry habitats (Site structure, regeneration mechanism, fauna, etc.), D and E). As the canopy is not closed due to the and traits of introduced plants (life form, shade usual arid condition, regeneration of Scalesia tolerance, drought resistance, dispersibility of occurs turn by turn in the canopy gaps (vacant seeds, growth rate, age at maturity, life span, space) continuously (Continuous Type Regenera- sprouting ability, pollination mechanism, devices tion). Thus the population is heterogeneous in against animals, etc.). In addition to these, age structure, in contrast to the homogeneous age human impacts (destruction, pollution, feral ani- structure in the forests of the moist windward mals. etc.) also play an important role (Fig. 157). area. De Vries & Tupiza (1990) recognized Among the various factors, the regeneration mech- several life classes (different cohorts) in a ,S. anism of Scalesia forests is especially important cordata forest at Velasco (Site D in this study). for establishment of introduced species. They also showed that many old Scc lesia trees I detected two types of regeneration mecha- died at the 1982-83 El Nifro event, but synchro- nisms of Scalesic forests which mainly depend on nous regeneration (germination of new seedlings) the habitat conditions (Fig. 158). Seedlings and did not occur after the event in the Sca lesia forest saplings of tree Scalesia usually grow fast, and at Velasco. This type of regeneration is true for S. make a developed forest with a closed canopy in microcephala forest in the dry habitats of Site E. moist condition (Sites A, B, C and F). Old trees As the life span of tree Scalesia is short ( 15 die synchronously because of unusually heavy years for S. pedunculata estimated by Hamann rain fall at El Niflo events. Other factors like (1979a) and 2C-4O years for S. cordata estimated insects or parasite attack may cause a concentrat- by de Vries & Tupiza (1990)), it is speculated ed death in some cases. New seedlings genninate that the Continuous Type regeneration could at the same time in the open forest floor, and occur even in the moist condition as seen in Sites grow rapidly to make the next generation of B and F, if the events to reset the forest regener- forest which is composed of even-aged population ation would be delayed. So which type of regen- (Synchronous Type Regeneration). eration mechanism occurs is affected greatly by This type of regeneration is the same mecha- the impact of trigger events and the duration nism as studied in ,S. pedunculata forests by between two successive events. Hamann (1979a) and ltow & Mueller-Dombois ( 1988) in Los Gemelos, Santa Craz and in S. 2. Invasion of introduced plants cordata forests by de Vries & Tupiza (1990) in Invasion of introduced plants is usually delayed Sierra Negra, Isabela. Itow & Mueller-Dombois under closed canopies, but it may progress greatly ( 1988) explained the phenomena as the concept and rapidly at the time of synchronous collapse of of stand-level dieback. The most recent El Niflo the canopies in case of Synchronous Type Regen- which brought extremely high rainfall to the Ga- eration. Hamann (1985) also stated that some l6pagos occurred in 1982-83 (see Fig.3). plants had a higher chance of successful immigra- Hamann (1985) found that Scalesia trees of var- tion during a Nifro event than during normal - 115 - Regional Views No.11 1997 Sca■ esュa Forest Biological Elaments <-) Environmental Elenents . Species composition . Location (1ife forrns, population size, (latitude, longitude, attitude) evergreen or deciduous) . Geology . Forest structure (1and forn, aspects, inclination, (canopy height, coverage, kinds of rocks, depth of soils, stratification, area, DBH, degree of weathering) dj-stribution pattern, liqht condition) . Climate (temperature, precipitation, oRegeneration mechanism wind direction & velocity, (disturbance oriented or frequency of fog) gap dynamics) o Special events . Fauna and fl-ora (Ef Nino, erruption of volcanoes, (grazing, pollination, disease, drought, fire, storm, landslide) seed dispersal, germination) Human lmpacts Direct : developmeot, pollution, touri sm Indirect: feral animals Introduced Plants . Life form (tree, shrub, herb, vine) ' Shade tolerance (pione€r, climax ) . Drought resistance . Seed dispersibility (abundance, distance, dormancy, dgents ) . Growth rate . Life span . Sprouting ability . Age of maturity . Pollination mechanism .Resistance against fire Fig. 157. Elements concerning the invasion of introduced plants into Scalesia forest. 一H6- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Dry Condition MOist conditiOn \ v SapJ-inge OPen canopy I u1osec canoPy , I (different-age tr //^ H@J-asepopul:::_, ???.*rffi _. //.ta\ I - / ...r.,r4.r-J e+e+e+b+?+g i-,. Gap regeneration Vtbli--. , ,, tl' tt-- ?to?r*f+o_)l \ ------a? - T: 't?ff?f?.-El Ninc J, ,"n.""un." ff?ilt??I I n*hlf*h^^^^ V ? scalesia spp. -lil + rntroduced plants ?,? Young or old, treeg ?,1 Dead treeg / Introduced plant f. Main-route of regeneration regf€neration Fig.158. Schematic preeentation of the regeneration nechanigms of Sccrssia forect and the invacion of introduced plants. Table 4. Comparison of ecological characteristics among Scalesia spp. and three introduced plants Scalesia spp. Psidium guajava Cinchona succirubra Lantana camara Life form (Max. height) 2 Shade tolerance I Drought resistance 2 Early growth rate 3 Seed dispersibility I Sprouting ability I Life span I Total Numerals show the tentative evaluation (l-3; 3 is highest). years. On the other hand, it is possible that the and the Highland (Fern-Sedge) zone in 1965. invasion proceeds little by little continuously in The first control program (uprooting of the small canopy gaps in case of Continuous Type Regener- plants and digging out of larger individuals with ation (see Fig. 158). picks) started in 197l, but it spread to about The method of invasion owes to traits of intro- 4,000 ha in 1987. The density was high near the duced species. Table 4 shows the comparison of south boundary of the National Park area,lower seven characteristics among tree Scalesia species between Media Luna and Mt. Puntudo, and none and three introduced plants studied in this paper. was observed on the western slope of Mt. Cro- Cinchona succirubra was introduced to Santa cker in 1987 (MacDonald et al. 1988). I found so Cruz in 1946 for the first time, and a few were many Cinchona trees invading from the south established at the Moist-scrub (Miconia) zone boundary of National Park area to the southern - 1t7 - Regional Views No. I | 1997 slope of Mt. Crocker through Media Luna and which lacks real climax species. This situation is Mt. Puntudo in 1995. It seems that its invasion very similar to that of the Bischofia javanica inva- has stopped just in front of the Scalesia forests sion in the Bonin Islands (Shimizu 1995). I with closed canopies in Site A and Site B, Santa worry that Cinchona may invade the Scalesia Craz (see Fig. 5). forests rapidly at the next El Nifro event when Cinchona is not a dominant tree in its native bright and moist condition is realized after the forest habitats in the Ecuadorian mountains canopies of Scalesia forests collapse all at once. where it occurs naturally, but it spread rapidly Psidium guajava is rapidly spreading to the into the native vegetation in the Galiryagos with sparse Scalesia forests (Site D) or the fragmental its advantageous characteristics such as rapid Scalesia forests left in the vast Psidium forests growth, early maturity, wide ecological tolerance, (Sites C and D) in Isabela. It is also increasing in a large amount of wind-dispersed seeds, and sp- the central part of Santa Cruz (Sites A and B) routing ability (MacDonald et al. 1988). It is and Floreana (Site F). Psidium is more shade- generally thought that germination and seedling tolerant than Cinchona, so it can endure dark growth of Cinchona occur under a wide range of condition under closed canopies. Psidium is in- conditions including deep shade (MacDonald et creasing its total dominance little by little in these al. 1988, Cronk & Fuller 1995). However, Cin- islands. Feral animals (pigs and donkeys) as well chona seems to need bright conditions for estab- as birds play an important role in dispersing seeds lishment of seedlings judging from the fact that it of Psidium widely. But dispersibility of seeds is can never invade Scalesia forests with a closed less than Cinchona. canopy. In addition, small winged seeds dis- Both Cinchona and Psidium ( 1) make large and persed by wind and its vigorous growth in sunny dense canopy which shade out light-demanding places along paths suggest that Cinchona is origi- species like Scalesia, (2) elongate new shoots nally a pioneer (light-demanding) species. Sap- from the base when main stems are damaged, (3) lings found in deep shade might have germinated have longer life span than Scalesia, (4) do not die when the canopy was open in the past. Once even at El Nifro events. So once they succeed in seedlings grow up to saplings, they acquire shade- invadin g Scalesia forests, they take the place of tolerant ability to some extent and they may Scalesia to make a dominant forest of their own. endure under the closed canopy for several years. Fragmentation (breakdown of closed canopy) of Cinchona seems to need moist condition as well natural forests accelerates invasion of the intro- as bright condition for establishment, because the duced plants. distribution of Cinchona in Santa Cruz coincides Lantana camara is a shrub species, which is not with moist mountainous area. Many small seed- a competitor of tree Scalesia in the usual sense. lings were found on a moist mossy ground near However, if it covers the ground of Scalesia fore- Media Luna, while no such seedlings were found sts densely as seen in Floreana (Site F), it is on a dty, thin-soiled ground in the Highland zone. difficult for seedlings ofScalesia to establish them- The coverage of Pteridium aquilinum must be selves even if the canopy of Scalesia becomes open related to the invasion of Cinchona in the High- at El Nif,o events. So Sca/esla forests will gradu- land zone. Cinchona can not establish under the ally change to Lantana scrrub in the end. On the dense coverage of Pteridium, so the invasion other hand, Lantana is also a light-demanding might have advanced rapidly and greatly just species, thus it will disappear from the forest if after the Pteridium thicket died widely in a se- the forest canopies become fully closed. A herba- verely arid year and before it recovered complete- ceous species, Calanchoe pinnata, has a similar ly, for example. effect on regeneration of Scalesia forest in Sites C MacDonald et al. (1988) suggested that the and F. dominance of Cinchona in the Gal6pagos owed to There is an opinion that Trema micrantha is the lack of biological controllers. However, I not a native but an introduced species (Wiggins & think the unique island ecosystem and the com- Porter 1971, Nowak & Lawesson 1988). Howev- petitive relationships among plant species are €r, it is not strange that a nativ e Trema species main causal factors. The characteristics of Cin- exists in oceanic islands, because species of this chona mentioned above may not be so advanta- genus are usually pioneer trees producing small geous in the original habitat with many climax edible fruit dispersed by birds (good for long- (shade-tolerant) species, but they must be effec- distance dispersal). In fact, Trema orientalis is tive in invading the ecosystem of the Galfpagos distributed naturally in remote islands such as the -118-一 Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimi"u) Hawaii and the Bonin Islands. Judged from the bility that thick cover of ferns should not allow situation of Trema micrantha in Alcedo (Site E) new cohorts of Scalesia to emerge in many years. where no other introduced trees are found, this Pteridium aquilinum began to appear on the species must be native to the Galfpagos Islands. ground just after the fire. It has covered the open Trema micrantha is a typical pioneer species in floor of burnt forests so densely in one year that it the secondary succession as shown in the burnt must prevent seedlings of tree species other than area in Site C. Large trees of Trema are dis- Psidium from establishing. So species composi- tributed on a dry habitat made of pumice and ash tion of the Shrub and the Herb layers would accumulation which is not matured in Site E. The remain poor in contrast to the rapid recovery of vegetation of Site E seems to remain in an early canopies. When the canopy is closed again, the stage of primary succession (a kind of edaphic pioneer Pteridiutn would disappear, and instead, a climax). Welff (1980) stated that Alcedo was in shade tolerant species, Ctenitis sloanei, would an intermediate phase, that is, it had passed the grow frequently in the Herb layer. stage of colonization of base volcanic substrate, No Sca lesia trees which died of the fire had new but had not yet reached the florally and structur- shoots from the base of trunks like Psidium gua- ally more complex stage of forest. Trema micr- java. So the patchy Scalesia forests disappeared in antha plays an important role in the vegetational some places after the fire, and maybe Psidium succession together with tree Scalesia in the Ga- would establish and take over the places. I found l6pagos. donkey droppings which contained many seeds of Persea americana is invading the Scalesia fore- Psidium on an open fire-break belt just after the sts in Sites A, B and C. But it is not so aggressive fire. Feral donkeys and pigs are effective seed probably because of its large, heavy seeds which dispersers of Psidium in this area. Nowak et al. are difficult to be dispersed over a long distance. (1990) stated that some endemic and rare taxa Saplings are found only around a parent tree. But had very little or no regeneration, whereas intro- it grows up to a tall tree with a large crown, so it duced species showed a high degree of survival shades out native plants around it. Citrus spp. and regeneration after the 1985 fire. seem to be increasing in Site F. They establish Small patches of Scalesra saplitrgs, 2-3 m high, themselves under the canopies of Scalesra forests, were found at forest margins or in canopy gaps. I so they would prevent regeneration of the forests could find adult trees which survived the fire in in some places. these places. It is clear that these saplings germi- nated after the fire. But it is not sure whether 3. fnfluence of the 1994 fue they came from buried seeds under the ground or The 1994 fire burned a wide range of forests newly dispersed seeds after the fire. Dr. Mauch- (about 35-45 k-') at Alemania (Site C area) in amp in CDRS told me that he studied new Seale- Isabela (Marquezet al. 1994). The altitude of the sia saplings in places where no adults were left burnt area ( 150-450 m) is comparable to the around them. Kastdalen (1982) reported that lower part of the Moist-forest (Scalesia) zone. It extensive damage to the under-brush by pro- was lucky that most of the burnt area was the longed droughts in 194y',-45 and grazing by cattle secondary forest of Psidium guajava. But small in part made an ideal combination of circum- patches of Scalesia cordafc forests which had been stances for regeneration of Scalesia, and the suc- left in the Psidium forests also burned in some ceeding garua season showed a fantastic recovery places. When I saw the burnt forest just after the of the Scalesia forest. These facts suggest that the fire in June, 1994, the burnt stems of Psidium saplings were derived from buried seeds. guajava seemed to be alive, even though crowns On the contrary, the saplings growing in the were completely damaged (JICA 1994). But, I fire-break belt must have originated from newly recognized in April, 1995, that all the stems were dispersed seeds, because the soil and maybe dead about one year after the fire. Instead, new buried seeds were removed by bulldozers at the shoots sprouted vigorously from the base of the time of construction of the belt. The patches of dead stems. They were l-2 m high at the time of Scalesia saplings which had germinated after the survey. The new shoots of Psidium would grow fire are all small in Site C. Even a farthest sapling fast to make a new Psidium dominant forest in a is located within 2O m from the supposed seed few years, which is nearly the same as that before source (adult trees which survived the fire) in this the fire. study. If seeds buried under the ground is effec- De Vries & Tupiza (1990) suggested the possi- tive for germination after the fire, the distribution 一-119-一 Regional Views No. 11 1997 of saplings should be more wide and prevalent by other species even if its speed was slow. Fires unless the seeds were damaged in burnt area. So caused by volcanic eruptions must have been a the contribution of buried seeds seems to be little trigger of regeneration of old Sca lesia forests like in this case. El Nifro events. However, Psidium guajava in- As a general feature of pioneer plants, Scalesia vaded burnt area faster than Scalesia, if seeds of produces a lot of small and slender seeds in the Scalesia were not dispersed effectively after the end of rainy season. The light seeds are apparent- fire. Psidium would take over the places in the ly easily dispersed by wind, but in fact, the dis- end. So fires accelerate the invasion of introduced tance of dispersal may be shorter than we imag- species (see Fig. 158) and lead to loss of remnant ine. An isolated tree of S. pedunculata on Santi- Scalesia forests at present. ago had many seedlings growing around in a radius of about 20 m (De Vries & Tupiza 1990). 4. Comparison of three species of tree Scalesia The number of S. cordafa seedlings which emerg- The three species (5. pedunculata, ,S. cordata ed after the fire decreased sharply with the dis- and S. microcephala) among fifteen Scalesrc spe- tance from a parent tree and almost all individu- cies in the Galiryagos take a true "tree" growth als were located within 2O m from the supposed form. They form a moist forest at the middle parent in Site C. It is thought that the dis- altitude of severallarge islands (see Fig. a). They persibility of the ancestral species of Scalesia has are taxonomically different species which seems to reduced with the process of evolution in the is- have evolved in the different islands, but they lands (It may be an example of loss of dis- have almost the same features ecologically. They persibility noted by Carlquist 1,974). This low all have the traits of "pioneer plant" such as seed dispersibility is a crucial weak point of Scale- production of many light seeds dispersed by wind, sia compared with other introduced species (see light-demanding feature, high growth rate of see- Table 4). The direction of prevailing wind has dlings and saplings, tolerance of aridness, and so also an important meaning for seed dispersion on. The tree height is variable according to the On the other hand, Scalesia surpasses any other habitat conditions. They make a dense forest trees in the growth rate of seedlings. It is surpris- with a closed canopy in moist habitats, while they ing that Scalesia seedlings grow up to max. 3 m form sparse forest with a broken canopy in dry height within one year after germination. This is habitats. Though S. microcephala is the smallest a great advantage of Scalesia over the introduced in height among the three species and it makes a trees. EvenPs idium guajava and Pteridium aquilin- sparse forest on the dry habitat in Site E, it must um can not establish within the patch of Scalesia be larger and the canopy is more closed in the saplings, because the Scalesia saplings grow dense moister habitat of windward slope of Alcedo. making a closed canopy together from the begin- The regeneration mechanism is also common ning. If the saplings of Scalesia continue to grow among the three species. They take Synchronous favorably, they would form a small Scalesia Type Regeneration in moist and dense forests, stand. Nowak & Lawesson (1988) studied the while they have Continuous Type Regeneration in regeneration of Scalesia cordata after the 1985 fire dry and sparse forests. So they would get nearly at Sierra Negra (nearly the same area as Site C), the same influence from El Nifio events and fires. and found that Scalesia saplings, 3 m high, were The invasion of introduced trees also proceeds in killed in some places by plagues of snails, and the same way in the Sca lesia forests. It is an butterfly and beetle larvae. These plagues may interesting problem that the evolution from shrub happen again. to tree habit occurred only once and then the It is said that the 1994 fire was caused by local ancestral species diversified to the three species, hunters accidentally (Marquez et al. 1994). But or it occurred three times independently in the there must have been natural fires caused by past. Genetic analysis will make it clear. volcanic activities in the past. Though Scalesia is Many trees, shrubs and herbs are associated not tolerant to fires, Scalesra forests could recover with Scalesia forests (Table 5). Most of them are from new seedlings which had germinated after common irrespective of the canopy species (three the fires. In fact, Hendrix & Smith (1986) found species of tree Scalesia). Among 61 woody spe- that Scalesia cordata recovered well from seeds cies which appeared in the seven sites (including after the 1968 eruption in Fernandina. In the the study sites for S. afinis as one site) studied in time before many plants were introduced by man, this paper, 16 species were found in more than the regeneration of Scalesia was not interrupted three sites. As for herbaceous species, 37 out of 一-120-一 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Table 5. Frequency of occurrence of all species which appeared in the plots Four sites of S. afinis are grouped in Site SA. Site A Site B Site C Site D Site E Site F Site SA No of plots 10 10 16 20 12 12 8 TlJayer Acnistus ellipticus Bursera graveolens 2 5 Cinchona succintbra 1 1 Croton scouleri 3 3 Opuntia echios v. inermis 1 Opuntia insularis Persea americana 1 1 Pisonia floribunda 4 1 Psidium galapageium 1 4 1 Psidium guajava 11 5 Sapindus saponaria 1 Scalesia cordata 7 10 Scalesia microcephala Scalesia pedunculata 4 7 Tournefort i a pub e sc e n s 1 2 Trema micrantha 1 3 Zanthoxylum fagara 1 3 3 T2-layer Acnisus elliptictts I Buneragraveolens 3 4 5 Chiococca alba 4 | Cinchona succirubra 4 4 Citrus lirnetta I Cirnrs sp. 3 Clerdendntm molle I Cordia andesonii I Cordialeucophlyctis 2 3 5 Cordia lutea I Cordia rqolun I Cordia scouleri I Crcton scouleri 2 S ll I Jasminocereus thouanii v. thouanii I Opuntia echios v. gigantea I Opuntia echios v, inermis I Penea atnertcana I Pircidio carthagenensis I Pisoniafloribunda I I 3 Psidiumgalapageium | 7 Z I Psidium guajava I 14 g 5 Psychotria ntfipes I Scalesia afinis 2 Scalesia ardan 6 lO Scalesia micrccephala 7 Scalesiapdunculata 4 7 ll Scutia pauciflom I Tournefortia psihsnchya I I Tournefortiapubescens I 9 5 3 3 I Tournefortiarufosericea 3 2 g Trema micrantha 4 Urea caracasana I Walteria ovata I Zanthoxylumfagara4lo4l4l ―-121-― Regional VievJs No。 11 1997 Table 5。 (Continued) Site A Site B Site C Site D Site E Site F Site SA plots No of 10 10 16 20 12 12 8 S-layer Acasia rorudiana Acnistus ellipticus 1 2 2 Altenanthera echinocephara Baccharis gnidiifolia Bursera graveolens 1 Capraria biflora Capraria peruviana 1 Capsicum frutescens 1 1 Cassia picta 4 6 Castera galapageia 1 2 Chamaesyce viminea 2 3 Chiococca alba 537112 Cinchona succirubra 5 1 Citrus limetta 1 Citnts sp. 2 Clerodendram molle 6 Cordia andesonii 1 2 1 Cordia leucophlyctis 12 7 5 Cordia lutea 1 Cordia revoluta 1 Cordia scouleri 1 Croton scouleri 2 4 10 1 Danv iniothamnus lancifolius 7 D anv in io thamnu s t enuifo liu s 4 3 2 2 Dodonaea viscosa 1 Gossypium barbadense v. darvtinii 4 Lantana camara 8 1 Lantana peduncularis 3 4 L ecoc arpus p innatifidus 1 Macraea lartcifolia 5 6 Miconia robinsoniana Opuntia echios v. inermis 3 Opuntia insularis 2 Persea americana 1 Pisonia floribunda 1 1 2 Pleuropetalum daruinii 1 Psidium galapageium 1943 Psidium guajava 2 1 14 11 11 Psychotria angustata 1 Psychotrta rufipes 4 7 1 Rabzs sp. 1 Sarcostema angustissima 4 Scalesia afinis 7 Scalesia cordata 6 8 Scalesia microcephala 8 Scalesia pedunculata 1 1 5 Scutia pauciflora 1 3 Sida rhombifolia 1 4 Tournefortia psilostachya 3 1 3 4 Tournefortia pub esc en s 0663 T o u r n efo r t i a rufo s e rtc e a 4 5 3 13 4 2 Trema micrantha 4 3 Urea caracasana 1 Yallesia galbra 1 一-122-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Table 5。 (Conttnued) Site A Site B Site C Site I) Site E Site F Site SA plots No of 10 10 16 20 12 12 8 Walteria ovata Zanthoxylum fagara 2 4 ll l0 4 8 H-layer Abutilon depaupemtum 9 12 2 Acalypha pamula 1l I Adenostemma lavenia 2 Adianthum matophylum I Adiantum henslovianum 9 7 Ageratumconyzoides | 4 6 Altenanthera fiIifolia 4 Altenantherahalimifolia 2 6 4 2 3 Amaranthus gracilis I Anredem ranosa I Anthephora hermaphrcdita l0 9 Apium leptophyllum I Aristida divulsa 3 Asplenium auritum 5 5 Asplenium cfistatum 3 Aspleniurn feei | 2 Aspleniumformosum 2 5 6 lsplenium paraemonturn? | Asplenium serm I Bidms pilosa 2 Bidens riparia 12 5 Blainvillea dichotoma 12 8 Blechnum occidentale 3 I Blechnum polypodioides 5 4 Blechum brownei f, pubentlum 3 2 2 | Boehaavia erecta Boutelona disticha 2 5 Brickellia difusa 5 Capsicttm frutescens I Cassia occidennlis 4 Cassia tora 4 Cenchrus platyacanthus 9 Centellaasiatica I 2 2 2 Chamaesyce punctulata 3 Chrysanthellum pusillum 4 Cissampelos pareim I I Cissus sicyoides I Cloularia incana 2 7 Clotalaria pumila 1 5 Commerinadifisa 3 3 7 3 I Commicarpus tuberosus 7 Conyza bonariensis 5 2 Ctenitissloanei | 7 13 6 4 Cuscuta gJ,mnocarpa 3 Cyperus andesnii Cyperus brevi.folius I Cyperus anfertus I Cyperusspp. I I I I 2 Dennstaedtia glofuldera 2 Desmodium canum I I Desmodium glabrum 6 ―-123-― Regional Views No。 11 1997 Table 5。 (Continued) Site A Site B Site C Site D Site E Site F Site SA No of plots 10 10 16 20 12 12 8 Desmditm prccumbens I Digitaria adscendens 3 I Digiuria horinnnlis I Diodiamdula 4 5 13 4 | I Diplazium subobtusum 2 Doryopterispedan 2 5 11 I 3 Drymaria cordata 2 2 Elaphoglonm firmum? I Eleocharis sp. 1 Epidendrumspicatus 1 I I Euphorbia sp. I Euphorbia tireanii I Fleurya aestuans I Galactiastrian I 3 I Galactia tenuiflorz 4 Galium galapagense I Graminaespp, I I I Heliottopiumangiospermae I 3 2 2 Hyperic,um uliginosum I Hypolepis hostilis? I Hyptismutabilis 9 2 I Hyptis rhomboidea 4 | Ichnanthusnemor.osus 3 2 I Ipomoea alba 3 Ipomoea hair I Ipomoea nil 2 3 Ipomoeatriloba 3 5 I Justiciagalapagana 3 2 I Kalanchoe pinnata 3 I Lyapodium clavatutn 2 Malvastntm corcmandelianum l0 5 I Muardonia dianthea I 5 Menuelia aspera 2 4 Merrcmia aegptica I Momordia charantia I Nephtolepis cordifolia I I Oxaliscorniaian 4 | 4 Paspalumconjugatum 5 7 7 4 2 Passiflora colinvauxii I Passifura edulis I I Passiflora fetida 2 Pennisetum purpureum I Pennysetum pauperum 2 Peperomiagahpagensis 3 3 2 4 Pepercmia petiolan I 3 Phomden&onhenslovii I 5 I I Physalis pubescens 2 | Pilea baurii 2 Pityrcgramma calomelanos I Plumbagoscandens 5 6 2 Polygala galapagoensis 3 2 Polygonum galapageia 4 Polypodiumdispenum I 6 I Polypodium lanceohum I Polypdium phyllitidis 4 ―-124-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Table 5. (Continued) Site A Site B Site C Site D Site E Site F Site SA No of plots 10 10 16 20 12 12 8 Polypodium steirolepis 1 Polypodium tridens 1 3 1 3 Porophyllum ruderale 1 Potomorphe peltata 1 Pseudolephatopus spicatus 1 1 Pteridium aquilinum 71971 Pteris quadriaurita 6 Rhynchosia minima 14 8 Salvia occidentalis 1 1 2 13 3 3 Scleria pterota 1 Scoparia dulcis 3 3 Sida hederifolia 5 2 3 Sida rhombifulia 1 4 4 3 3 Sida salvifolia ? 10 1 Sida spinosa 8 8 Solanum nodiflontm 1 1 2 Sonchus oleraceus 3 2 Sporobolus indicus 1 1 S tachy tarph eta c ay enn e n sis 4 4 2 Stictocardia tiliifolia 1 5 Stylosanthes sympodialis 10 Synedrella nodiflora 5 15 1 Tephrosia decumbens 5 Thelypteris balbisii 4 2 1 Thelypteris oligocarpa Thelypteris patens Thelypteris tetragona Tillandsia insullaris Trachypteris pinnata 1 Uniola pittieri Verbena townsendii 3 1 vine sp. 10 Zornia piurensis 14O species also occurred in more than three sites. the habitat conditions are quite different from The most common species are Zanthozylurn each other. This phenomenon is explained as an fagar4 Chiococca alba, Tournefortia pubescens, example ofecological release ofplants in oceanic and T. rufosericea in woody species, and Diodia islands. radula, Salvia occidentalis, Altenanthera halimi- foliaCommeinadiffusa,Ctenitissloanei,Doryopt- 5. Relationship between tree Scalesia and S. eris pedata, Paspalum conjugatun, heridium aquil- afinis inum, and Sida rhombifolrc in herbaceous spe- I studied four sets of relationships between cies. Especially,Zanthoxylumfagara occurredin three species of tree Scalesia (5, pedunculata, S. all sites. This species takes a variety of growth cordata, andS. microeephala) and a shrubbyScc- forms from a tree to a procumbent shrub accord- lesia (5. afinis) in Santa Cruz (l set), Isabela (2 ing to habitat conditions. Large morphological sets), and Floreana (l set). The,Scclesro trees plasticity of plants is a characteristic of oceanic form a forest at moist mountain slopes in the islands. Hamann (1979b) showed a variety of middle altitude (Moist-forest zone), while ,S. leaf sizesandshapesof Crolonscouleri indifferent afinis occurs in the arid lowland area (Arid environments in the Gal6pagos Islands. It is zone) in all cases. The distribution of the tree and interesting that Scalesia forests and S. affinis the shrubby species never overlap with each scrubs have many common species, even though other, though the altitude and range of occur- ―-125-― Regional Views No. 11 1997 Santa Cruz IsabeJ.a Floreana /\/\ Sierra Negra Alcedo ▲ 小 ‐ ‐ ‐ ■ 400- 『 電 ■ ヽ “ σ 詞 ● ００ ＝ ■ 詞 ,A 『 ヽ０ 劇 コ ■ 封 v8300- υ ●■ ■ Ｈ ロ コ 日 酬 ＝ ■ ｏ Ｈ ■ ■ 。 ・ ０ ０ ０ ０ ０ ョ ヽ ヽ Ｊ 。 ｄ200- ● η・ Ｊ ｄ ‘ 100- η η η ０ 「 「 「 「 目 目 目 目 日 ヽ 「 Ц ＝ ヽ 「 Ｈ ヽ Ч 「 ” 呵 ■ 電 0- ． 。 ． 。 η η η 「 Fig. 159. Distribution prtterns of three speciec of tree Scalaia and S. ajtzic in the four ctudy cites. rence is different from each other (Fig. 159). of S. affinis. Itow (1995) pointed out that all Scalesia species Unusually much rain at El Nifro events may are completely allopatric in distribution. give more damage to S. affinis at the upper eleva- Why are they separate from each other ? It is tion than at the lower elevation, because the sure that tree species of Scalesia prefer moist amount of rainfall seems to be proportional to the habitat, and S. affinis is adapted to arid environ- elevation (see Fig. 3a). On the other hand, tree ment. In addition to that, both species need open Scalesia may enlarge its distribution toward the habitats when they regenerate. Difference of Semi-arid zone in wet years, but they may recede temperature along the altitudinal gradient seems againin ordinary arid years. The important thing to have little effect on their segregation. One is that dispersibility of seeds is relatively low in all possible hypothesis is this: ,S. affinis with the Scalesia species. So, once they separate, it is height of max. 2 m is susceptible to shade by difficult to merge again. The non-overlapping other trees. So, ,S. affinis will disappear from a distribution may owe to unusual climate condi- place in the long run unless the place supplies tions as well as ordinary ones. open habitats one after another around it. It is suggestive that S. affinis goes up to the highest 6. Growth forms of tree and shrub species of elevation in Site E where open habitats are dis- Scalesia tributed most widely among the four study sites. Tree Scalesia grows up about 2-3 m tall within It is known that biomass of vegetation increases one year after germination in moist habitats. As at El Niflo events, so the unusual dense coverage shown in several sites, main stems elongate strai- occuring just after the events results in exclusion ght up to 5-6 m high, then they spread branches - 126- Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Fig. 160. Branching pattern of a Scalesia tree. upward. When they reach the height for matura- with the age of the forest estimated from the last tion, they produce inflorescens atop the current El Nifro event in 1982-83. shoot, and next branches come out laterally. The Scalesia affinis has the same branching pattern same pattern of flowering and branching contin- as that of tree Scalesia, but it never becomes a ues year after year, thus the crown becomes larger tree. Fig. 161 shows a schematic presentation of and heavier exponentially (Fig. 160). developmental stages of S. affinis. It usually takes On the other hand, the wood of tree Scalesia is a multi-stemmed and procumbent growth form soft and weak, maybe because they have evolved which must be an adaptation to the arid and from a herbaceous ancestor. It seems that the thin-soiled environment. It spreads branches to stem and root system of tree Scalesia can not all directions, forming a semi-spherical crown. support the large and heavy crown of itself for a However, the branch with much leaves at the tip long time. So large trees easily collapse by strong easily collapses to the ground and dies, so the winds as seen in Site F, or by decaying of root large crown above ground can not be maintained systems at El Nifro events. The physiological so long. It is difficult to estimate the age of S. mechanism may not be fully adapted to maintain affinis individual because the counting of nodes is large amount of leaves in the crown. This seems not so easy as tree Scalesia, but the life span of S. to be related with the fact that many living Scale- affinis is probably not so long. It is characteristic sia trees have some dead stems and branches in that old dead leaves remain on a stem for several their crowns and the crowns never overlap with years after they withered, densely covering the each other. Fortun ately, hurricanes never attack stems and branches. They may be useful to keep the Gal6pagos Islands. If they hit the islands, the moisture in the plant body. damage to Scalesic forests would be beyond imag- ination. 7. Effects of feral aninals I recognized the "yearly node" on the trunk It was a custom of whalers and navigators to and branches of tree Scalesia. It seems that one release goats and pigs to remote islands for their node coincides with one year, because the node future food. This must also have been true for the shows the elongation between one year's and the Galfipagos. In fact, at the time of Darwin's visit next year's flowerings. I could count the nodes of in 1935, many goats were observed on Floreana trees up to I I in Site B (Plot B 1) (Los Gemelos, (Koford 1966). In addition, the later settlers to Santa Cruz). Thus the number of nodes coincides the Gal6pagos introduced domestic animals such -127- Regional Views No. 11 1997 Y 'y)(i,0, Fig. 16l. Life form cycle of Scalesia afi.nis. as goats, cattle, horses, pigs and donkeys from the tation. Eradication programs were carried out late 19th century to the early z0th century. These and accomplished in South Plaza, Santa F6, Esp- animals have gone wild and given serious damage afiola, Marchena, Rabida and Pinta so far (Sch- to the native ecosystem which originally lacked ofield 1989). Feral goats have increased greatly large mammal herbivorers (Hoeck 1984, Scho- since the early 1990's in Alcedo, Isabela and have field 1989, Jackson 1993). caused serious destruction of vegetation (Cayot & Feral animals affect the ecosystem in various Snell 1996). The destruction is occurring mainly ways: ( 1) they eat endemic plant species directly, on the moist southern rim and slopes of the reducing them in numbers or leading them to mountain. A new eradication program started in extinction, (2) they disturb habitats by browsing 1995. I saw a herd of goats on the eastern rim of and trampling, providing open spaces, or crater, but I did not detect any serious damage of changing nutrient balance, thus letting other alien goats on the vegetation with Scalesia micro- plants invade more easily, (3) they help the cephala on the eastern slope of the mountain (Site spread of introduced plants in native vegetation E). We should keep an eye on the condition of by eating fruit and dispersing seeds, (4) they this slope, too. interfere with regeneration of forests by eliminat- ing seedlings and saplings of canopy trees, thus 8. A plan to preserve and restore Scalesia for' destroying the vegetation in the end, (5) they ests compete with endemic herbivores such as land Preservation of Scalesra forests is classified into iguanas and giant tortoise by eating the same kind three categories as follows (Fig. 162): of food plants, thus causing the decrease of their number. In this study, I saw pigs, cattle, and ( 1) Keeping natural condition (preventing fur- donkeys in Site C, pigs, donkeys, and horses in ther invasion) Site D, goats in Site E, and cattle and donkeys in Choose a protect area where a Scalesla forest is Site F. I also found many cattle in private pasture still preserved in natural condition and then clas- lands near Site A and Site B. sify the area further into Core zone (inside) and Among the four feral animals, goats are the Buffer zone (outside). It is better to surround the most harmful, because they eat grass and herb to Core zone by fences to keep feral animals out (to the roots, exposing the soil to erosion. They prevent further dispersal of introduced plants by adapt to adverse conditions so well and multiply animals). Monitor the condition of the protect so quickly that they thrive in many islands in the area periodically. If you find invasion of an Galfupagos and have destroyed their native vege- introduced plant, eradicate it as soon as possible. - 128- Competitive Relationships between Tree Species of Scc/esia and Introduced Plants (Shimizu) ？ キ ScaJ'esj'a Introduced plants ー ( f nrras ive ) Introdueed pJ,ants ( j- Non rrva s i.re ) 奸 “ 啓ふ′11缶‐1 ィ“ | 、下嵩 Disturbed area Fig. 162. A plan to preserve and restore Scalesia forest in an imaginary island. Core zone should not be used for any human same or other introduced plants will establish activities including eco-tours. there again. To reduce seed source of introduced plants in (2) Eliminating introduced plants and animals private lands, ask for cooperation of land owners Eradicate all introduced plants and feral ani- to eliminate harmful plants from their farm lands mals first from Core zone and then from Buffer and show them alternative way (for example, zone. It is supposed that eradication in Buffer agroforestry project being done in Sant a Cruz) . zone takes a long time (many years). It is better to find usage of introduced plants, for example, (3) Restoring Scalesia forest in disturbed area wood carvings for tourists, housing materials, fire (original habitat) wood or charcoal, and extracting chemicals from Scalesia is superior to the introduced plants in leaves or roots. Prior to the practice of eradica- the early growth rate of seedlings (3 m high in a tion, test carefully the influence of eradication on year in a good condition). Saplings make a dense native plants and animals. Biological methods coverage for the first several years, so even intro- (for example, introduction of some host-specific duced species may find it difficult to invade the parasites) is attractive, but be prudent in adopting regenerating place if the coverage is wide and such risky methods in small oceanic islands like complete. On the other hand, Scalesia has lost the Gal6pagos, because it might give unexpected efficient dispersal ability of seeds while it still effects on native creatures. Take care of the needs much light for germination as a pioneer spaces after introduced plants are eradicated (for plant. Seedlings of Scalesia can enter an open example, planting of native plants), otherwise the place only if seed source (matured tree) is close to 一-129-― Regional Views No. 11 1997 the place. Galiryagos No 56: 5-9. So if we help Scalesia by making open land Hamanr, O. 1979a. Dynamics of a stand of Sca- (eliminating competitors by bulldozing the lesia pedunculata Hook fil., Santa Cruz Island, ground) and dispersing seeds there at the appro- Galfupagos. Bot. Journ. Linn. Soc. 78: 67-84. priate time (beginning of rainy season), it is pos- Hamantr, O. 1979b. On climatic conditions, veg- sible to restore Scalesta forest again We can get etation types and leaf size in the Gral6pagos seeds of Scalesia in Core zone of protect area in Islands. Biotropica I 1: l0l-122. each island. Hamantr, O. 1981. Plant communities of the Ga- lfpagos Islands. Dansk Bot. Ark. 34(2): l- Acknowledgments 163. HamanD, O. 1985. The El Nifio influence on the I wish to express my thanks to Dr. Chantal GaLfupagos vegetation. Pages 299-330 in Rob- Blanton, Director of the Charles Darwin Re- inson, G. & del Pino, E. M., eds. The 1982-83 search Station, and Mr. Michael Bliemsrieder, El Nifio Event in the Galfpagos Islands Director of Galfupagos National Park Service, for Charles Darwin Foundation, Qnito. allowing me to carry out my field studies in the Hendrix, L. B. & Smith, S. D. 1986. Post- Galfupagos Islands. I extend my sincere thanks to eruption revegetation of Isla Fernandina, Ga- Dr. Andre Mauchamp for helpful suggestions in l6pagos: II. Natl. Geogr. Res. 2(L): 6-16. the course of this study, Mrs. Gayle Merlen for Hoeck, H. N. 1984 Introduced fauna. Pages 233- kind advice in library work, and Miss Lavta 245 in R. Perry, ed. Galfupagos. Pergamon Chellis and the staff of CDRS and GNPS for their Press, Oxford. support and encouragement in logistics and field- INGALA, PRONAREG & URSTOM 1989. work. I also thank the following persons for their Inventario cartografico de los recursos natur- company and help in fieldwork: Mr. Jacinto ales, geomorfologia, vegetacion, hidricos, ec- Gordillo and Mr. Arnaldo Tupiza in Isabela, and ologicos y biofisicos de las Islas Gal6pagos Mr. Anibol Son Miguel and Mr. Angel Naula in Ecuador, 159 pp. INGALA, Quito. Floreana. I also express my gratitude to Mr. Itow, S. 1983. The Galfupagos Islands-Cradle of Santiago Buitron who assisted me devotedly for Evolution Theory (new ed.) (in Japanese). the whole period of my research as assistant 2l2pp. Chukou Shinsho Books, Tokyo. fellow. I cordially acknowledge the valuable Itow, S. 1985. The Galfupagos Islands-Evolution advice by Dr. Shuzo Itow in planning and apply- and Ecology of Creatures (in Japanese). 80pp. ing for this study. Iwanami Graphics, Tokyo. Itow, S. 1992. Eco-tourism in the Galfupagos Na- References tional Park (in Japanese). National Parks 501: 8-13. Carlquist, S. 1974. Island Biology. 660 pp. Co- Itow, S. 1995. Phytogeography and ecology of lumbia University Press. Scalesia (Compositae) endemic to the Galfup- Cayot, L. & Snell, H. M. 1996. Goats damage agos Islands. Pacific Sciences 49: 17-30. Volcan Alcedo, Isabela. Noticias de Gal6- Itow, S. & Mueller-Dombois, D. 1988. Population pagos No 56: 3. structure, stand-level dieback and recovery of Christi€, D. M., Dancan, R. A., McBirney, A. R., Scalesia pedunculata forest in the Gal6pagos Richards, M. A., White, W. M., Harpp, K. S. Islands. F,cological Research 3: 333-339. and Fox, C. G. 1991. Drowned islands down- Jackson, M. H. 1993. Galhpagos-A Natural His- stream from the Galipagos hotspot imply ex- tory. 3 15 pp. University of Calgary Press, Cal- tended speciation times. Nature 355 z 24G248. gary. on the Influeuce of Cronk, Q.C.B. & Fullet, J.L. 1995. Plant Invad- JICA. 1994. Research Report Is- ers. Chapman & Hall, London,24l PP. the Fire in Isla Isabela of the Galfipagos De Vries, T. & Tupiza, A. 1990. The dynamics of lands (Ecuador), 73 PP. JICA, TokYo. Scalesia cordata (Asteraceae) in different hab- Kastdalen, A. 1982. Changes in the biology of itats in Sierra Negra, Isabela, Galfupagos. Santa Cruz Island between 1935 and 1965. Monogr. Syst. Bot. Missouri Bot. Gard. 32: Noticias de Galfupagos No. 35 z 7-12. 137-147. Koford, C.B. 1966. Economic resources of the Geist, D. 1996. On the emergence and submerg- Galfupagos Islands. Pages 286-290 in Bowman ence of the Gal6pagos Islands. Noticias de R. I., ed. The Galfupagos. University of Cali- 一-130-一 Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) fornia Press, Berkeley. Galfipagos. Pergamon Press, Oxford. Latorre, O. 1990. The Curse of the Giant Tor- Sayama, H. 1995. Dear Prof. Itow, I report the toise, 237 pp. Latorre, Quito. natural guide system in the Galilpagos Nation- Lawesson, J. E., H. Anderson, & P. Bentley 1987. al Park (in Japanese). National Parks 530: 12- An updated and annotated check list of the 18. vascular plants of the Gal6pagos Islands. Re- Schofield, E. K. 1989. Effects of introduced plants ports from the Botanical Institute, Llniversity and animals on island vegetation: examples of Aarhus No. 16, 74 pp. from the Gal6pagos Archipelago. Conserva- Lawesson, J. E. 1990. Alien plants in the Gal6- tion Biology 3: 227-238. pagos Islands-A summary. Monogr. Syst. Bot. Shimizu, Y. 1988. Vegetation of Mt. Kuwanoki in Missouri Bot. Gard. 32: 15-20. the Bonin (Ogasawara) Islands with reference MacDonald, I.A.W. , Ortiz, L., Lawesson, J. E. & to the invasion of an introduced tree species Nowak, J. B. 1988. The invasion of highlands (Bischofia javanica) (itt Japanese). Regional in Gal6pagos by the Red Quinene-tree Cincho- Views No 1: 31-46. na succirubra. Environmental Conservation Stone, C. P., Smith, C. W. & Tunison, J. T. 1992. 15: 215-220. Alien Plant Invasion in Native Ecosystems of Marquez, C., Gordillo, J. & Tupiza, A. L994. The Hawaii-Management and Research. 887 pp. fire of L994 and herpetofauna of southern Cooperative National Park Resources Studies Isabela, Noticias de Galfipagos No 54: 8-10. Unit. Munoz, E. 1993. Ecology of feral goats (Capra Tuoc, T. L. 1983. Some thoughts on the control hircus) on Alcedo Volcano. Noticias de Gal6- of introduced plants. Noticias de Gal6pagos pagos No 52: 2-3. No. 37 z 25-26. Nowak, J. B. & Lawesson, J. E. 1988. Revegeta- Werff, H. van der. 1979. Conservation and vege- tion of the burnt area in Isabela. Noticias de tation of the Gal6pagos Islands. Pages 391- Galilpagos No 46: 18-19. 404 in Bramwell, D. ed. Plants and Islands. Nowak, J. B.,WaLawesson, J. E., Adsersen, H. & Academic Press, London. de VrieS, T. 1990. A two-year study of post-fire Werff, H. van der. 1980. The vegetation types of vegetation dynamics on Southern Isabala, Ga- Santa Cruz and Alcedo. Noticias de Gal6pa- lSpagos Islands, Ecuador. Monogr. Syst. Bot. gos No. 31 : 1 1-13. Missouri Bot. Gard. 32: 123-136. Wiggins, I. L. &, Porter D. M. 1971,. Flora of the Porter, D. M. 1984. Endemism and evolution in Galfipagos Islands. 998 pp. Stanford Universi- terrestrial plants. Pages 85-99 in R. Perry, ed. ty Press, Stanford. - 131- Regional Views No. 11 1997 Photo 1. Scalesia pedunculata forest taking on a Photo 2. Invasion of Cinchona succirubra in a mossy appearance (April,1995; Site A) Pteridium thicket near Mt. Puntudo (April, 1995; Aite A) Photo 3. Canopy of Scalesia pedunculata forest Photo 4. A view of Psidium guajava dominant at Los Gemelos (April, 1995; Site B) forest just after the 1994 fire at Alemania (June, 1994; Site C) Photo 5. Experimental forest of Scalesia cordata Photo 6。 Fireabreak belt made at the time of the at Santo Tomfs (June, 1994; Site C) 1994■re at Alemania (June, 1994; Site C) 一-132-― Competitive Relationships between Tree Species of Scalesra and Introduced Plants (Shimizu) Photo 8. A kind of beetle (adult and larvae) living in a dead trunk of Scalesia cordata at Velasco (April, 1995; Site D) Photo 7. Parasite of Phoradendron henslovii on a branch of Scalesia cordata at Velasco (April, 1995; Site D) Photo 10. Feral goats on a ridge of the crater of Alcedo (May, 1995; Site E) Photo 9. Scalesia microcephala forest on a slope of Alcedo (May, 1995; Site E) Photo 11. Bursera graveolens with bright white Photo 12. Kalanchoe pinnata along a path at trunks like white birch at Alcedo Cerro Pajas (May, 1995; Site F) (May, 1995; Site E) - 133 - Regional Views No. 11 1997 Photo 14. A remnant forest of Scalesia pedunculata in a Lantana camara thicket at Cerro Pajas (May, 1995; Site F) Photo 13. Scalesia pedunculata forest inside the valley of Cerro Pajas (May, 1995; Site F) Photo 15. Scalesia afi.nis growing in an arid Photo 16. Scalesia afi.nis with a crashed crown vegetation at Alcedo (May, 1995; Site IBb) on a lava at Alcedo (May, 1995; Site IBb) - 134- Competitive Relationships between Tree Species of Scareslic and lntroduced Plants(ShimiZu) Appendix Species compositton of an the p10ts studied in this paper Numerals show the number of indi宙 duals(No)and basal area(BA:cm2)in Tl,T2,and S‐ layers,and the relative abundance(1-4)in H‐ layer and seedlings。 Dead individuals are shown in parenthesese Symbol(+)iS put to show presence of a sp∝ ies in case that evaluation of quantitiy¬ Ⅳas not done. Plot Noo Al A2 A3 A4 A5 Altitude(m) 660 680 710 700 450 Plot sizc(m× m) lo× 10 10× 10 10× 10 10× 10 10× 10 Crown height(m) 5 5 4。 5 4.5 15 Coverage(%♭ )Tl‐ layer 95 100 - - 30 T2‐ layer 0 0 50 40 10 S‐layer 10 5 0 5 60 H‐layer 90 85 95 90 100 No BA No BA No BA No BA No BA T1-layer Cinchona succirubra 2 1603 Persea americana Scalesia pedunculata 49 1911 73 2035 T2-layer Cinchona succirabra 7 452 6 461 2 70 Scalesia pecunculata (13) (176) (14) (92) S-layer Acnistus ellipticus Bursera graveolens Cinchona succintbra 7 490290(17) 325 Miconia robinsoniana 8 209 Psidium guajava Psychotia rufipes 49 Scalesia pedunculata Sida rhombifolia 6 Tournefortia rufosericea 3 Zanthoxylum fagara l(l) Seedling Acnistus ellipticus Cinchona succintbra Psychotia rufipes H-layer Ageratum conyzoides Alt e n an the ra h alim ifo I ia Asplenium auritum Asplenium feei Aspleniurn serra Blechnum occidentale Blechnum polypodioides Commerina diffusa Ctenitis sloanei Cyperus sp. D ennstaedtia globulifera Diodia radula 3 ―-135-― Regional Views No。 11 1997 Al A2 A3 A4 A5 No BA No BA No BA No BA No BA Diplazium subobtusum 1 Doryopteris pedata Elaphoglosum firmum? Epidendntm spicatum Galactia striata Graminae sp. Hypericum uliginosum Hypolepis hostilis? Hyptis rhomboidea Ichnanthus nemonosus Justicia galapagana Lycopodium clavatum N ep hro lep is c o rd ifo I ia Paspalum conjugatum Peperomia galapagensis Pilea baurii? Polygonum galapageia Polypodium trtdens Pothomorphe peltata heridium aquilinum Salvie occidentalis Sida rhombifolia Solanum nodiflontm Thelypteris balbisii Thelypteris oligocafpa Thelypteris patens Thelypteris tetagona Plot No. A6 A7 A8 A9 A10 Altitude (m) 710 705 640 700 560 Plot size (m X m) 6× 35 5× 15 10× 10 1ine line Crown height (m) 4。 5 6 3 20 1。 5 Coverage (Vo) Tl-layer ―- 95 -― T2-layer 40 0 -― S-layer 30 5 40 H-layer 95 100 80 No BA No BA No BA T1-layer Cinchona succirubra 十 Persea americana 十 Scalesia pedunculata 15 1592 T2-layer Cinchona succintbra 8 654 Scalesia pecunculata 12 781 (8) (165) S-layer Acnistus ellipticus Bursera graveolens 十 Cinchona succirubra 8 337 5 80 Miconia robinsoniana Psidium guajava 1 8 101 ―-136-― Competitive Relationships between Tree Speciee of *alesia and Introduccd Plants (Shimizu) A6 A7 A8 A9 AIO No BA No BA No BA Psychotriarufipes 9 4 70 Scaluia pedunc'ulan 8 330 (4) (loe) Sida rhombifolia Tournefortiarufosericea 3 I 4l Zanthoxylumfagara (l) (25) Seedling Acnistus elliptictts Cinchona succintbra Psychotria rufipes H-layer Ageratum conyzoides Altenan thera halimifolia Asplenium auritum Asplenium feei Asplenium serra Blechnum occidentale Blechnum polypodioides Commerina diffusa Ctenitis sloanei Cyperus sp. D enn st ae d ti a globulifer a Diodia radula Diplazium subobtusum Doryopteris pedata Elaphoglosum firmum? Epidendrltm spicatum Galactia striata Graminae sp. Hypericum uliginosum Hypolepis hostilis? Hyptis rhomboidea Ichnanthus nemorosus Justicia galapagana Lycopodium clavatum N ephrolep is cord ifolia Paspalum conjugatum Peperomia galapagensis Pilea baurii? Polygonum galapageia Polypodium tridens Pothomorphe peltata Pteridium aquilinum Salvia occidentalis Sida rhombifolia Solanum nodiflontm Thelypteris balbisii Thelypteris oligocarpa Thelypteris patens Thelypteris tetragona - 137 - Regional Views No. I | 1997 Plot No. Bl B2 B3 B4 B5 Altitude (m) 560 490 580 530 520 Plot size (m X m) 10× 10 5× 10 5× 20 5× 20 10× 10 Crown height (m) 6 4 7 10 5 Coverage (Vo) TlJayer 100 100 60 -一 T2-layer 5 70 5 5 30 S-layer 15 0 30 10 10 H-layer 80 15 80 10o loo No BA No BA No BA No BA No BA T I Jayer Cinchona succintbra Persea americana 1 547 Psidium galapageium Scalesia pedunculata 49 1997 31 1818 12 1481 Zanthoxylum fagara T}-layer Chiococca alba 3 4 1 7 Cinchona succitabra 10 580 Percea americana 4 31 Psidium galapageium Psidium guajava 2 17 Psychotria rufipes 1 Scalesia pedunculata 57 527 (27) (275) (14) (1143) (8) (148) (12) (845) Tourn efort i a pub e sc e n s Tournefortia rufoseric e a 1 85 1 4 Zanthoxylum fagara 4(1) 47 (1) (119) 5 176 S-layer Acnistus ellipticus Chiococca alba Cinchona succirubra 11 90 Persea americana 25 Psidium galapageium Psidium guajava 1 Psychotia rufipes 24 26 1 Rubus sp. 3 Scalesia pedunculata Sida rhombifolius 5 Tournefort i a p ub e sc en s Tournrfort ia rufosericea Zanthoxylum fagara Seedling Psidium guajava Scalesia pedunculata H-layer Adenostemma lavenia Adianthum macrophylum Ageratum conyzoides A I t e n an the ra hal i m ifo I i a Asplenium auritum Asplenium cristatum Asplenium feei ―-138-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Bl B2 B3 B4 B5 No BA No BA No BA No BA No BA Asplenium formosum 1 Blechnum occidentale 4 Blechum brownei f. puberulum Cissampelos pareira Commerina diffusa Ctenitis sloanei Cyperus sp. Diodia radula Doryopteris pedata Drymaria cordata Epidendrum spicatum Galium galapagense Ichnanthus nemorosus Justicia galapagana N ephrolep is cord ifolia Paspalum conjugatum Passiflora colinvauxii Passiflora edulis Pennisetum purpureum Peperomia galapagensis Peperomia petiolata Polypodium dispersum Polypodium phyllitidis Polypodium steirolepis Pseudolephatopus spicatus Pteridium aquilinum Pteris quadriaurita Salvia occidentalis Scleria pterota Sida rhombifolia Solanum nodiflorum S tic toc ard ia t il iifol ia Thelypteris balbisii Th elyp t e ri s oligoc arp a Thelypteris patens Thelypteris teffagona Plot No. B6 B7 B8 B9 B10 Altitude (m) 510 540 570 570 500 Plot size (m X m) 10× 10 10× 10 10× 10 8× 10 1ine Crown height (m) 8 10 5 3 Coverage (Vo) TlJayer 80 85 100 T}-layer 15 15 5 S-layer 40 5 5 H-layer 80 70 70 No BA No BA No BA No BA T1-layer Cinchona succirubra 3 492 Percea americana Psidium galapageium 1 597 Scalesia pedunculata 27 1988 14 1173 52 1958 1 42 Zanthoxylum fagara ―-139-― Regional Views No。 11 1997 B6 B7 B8 B9 Blo No BA No BA No BA No BA T2-layer Chiococca alba 1 1 Cinchona succintbra 1 79 1 40 Persea americana Psidium galapageium 1 5 Psidium guajava Psychotria rufipes Scalesia pedunculata 1 9 (14) (387) (6) (131) (14) (205) Tournefortia puiescens 1 55 Tou rn efo rt i a rufos e ric e a 1 Zanthoxylum fagara 4 53 S-layer Acnistus ellipticus Chiococca alba 4 Cinchona succirabra Persea americana Psidium galapageium Psidium guajava Psychotria n^tfipes 42 25 Rubus sp. Scalesia pedunculata Sida rhombifolius 3 Tournefortia pubescens Tournrfortia rufosericea l0 4 Zanthoxylum fagara 2 Seedling Psidium guajaua 4 Scalesia pedunculata ngel) H-layer Adenostemma lavenia Adianthum macrophylum Ageratum conyzoides 2 I Altenantherahalimifolia 2 I 3 Asplenium auritum I 3 Asplenium cristatum I Asplenium feei z Asplenium formosum 2 Blechnum occidentale Z 4 Blechum brownei f. pubentlum z Cissampelos pareira I Commerina difusa I I Ctenitissloanei 4 4 2 Cypents sp. Diodia radula 2 Doryopteris pedata 2 3 Drymaria cordata I Epidendntm spicatum I Galium galapagense Ichnanthus nemonosus Justicia galapagana N ephrolepis cordifolia -1“ ― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) B6 B7 B8 B9 B10 No BA No BA No BA No BA Paspalum conjugatum 3 4 Passiflora colinvauxii Passiflora edulis Pennisetum purpureum Peperomia galapagensis Peperomia petiolata Polypodium dispersum Polypodium phyllitidis Polypodium steirolepis Pseudolephatopus spicatus Pteridium aquilinum Pteris quadriaurita Salvia occidentalis Scleria pterota Sida rhombifolia Solanum nodiflontm S tic to c ar d i a t il iifol ia Thelypteris balbisii Thelypteris oligocorpa Thelypteris patens Thelypteris teffagona Plot No. Cl C2 C3 C4 C5 Altitude(m) 220 220 190 180 150 Plot size(m× In) 10× 10 10× 10 10× 10 10× 10 10× 10 Crown height(m) 5 4 9 7 10 Coverage(%♭ )Tl‐layer 100 5 90 80 35 T2‐layer 10 0 40 50 80 S‐layer 5 30 5 15 10 H‐layer 85 70 30 20 30 No BA No BA No BA No BA No BA T1-layer Acnistus ellipticus Croton scouleri 8 580 3 77 Pisonia floribunda 1 569 1 967 Psidium galapageium 1 82 1 38 Psidium guajava 30 819 4 47 3 78 1 218 1 108 Scalesia cordata 5 287 9 566 Tournefortia pubescens Trema micrantha 1 165 Zanthoxylum fagara 2 136 T2-layer Acnistus ellipticus Cordia leucophlyctis 1 88 Croton scouleri 12 144 13 12 (2) (90) (3) Pisonia floribunda 1 11 Psidium galapageium 1 5 5 97 Psidium guajava 11 50 7 183 7 49 1 5 (2) (414) (46) (481) Scalesia cordata 4 82 一-141-― Regional Yiews No. 1l 1997 Plot No. Cl C2 C3 C4 C5 No BA No BA No BA No BA No BA Touraefortiapubescens | 4 2 9 3 j3(2) lO 158 Tournefortia ntfosericu | 4 Urea caracasana | 29 Zanthoxylumfagam Z 122 2 37(j) lO Z4B S-layer Acnistus ellipticus Capsicum fnttescens Chiococca alba Croton scouleri 12 Pisonia floribunda Pleuropetalum daruinii Psidium galapageium 2 Psidium guajava t2 Psychotria rufipes Scalesia cordata Tou rneforti a p s ilo s t ac hy a Tournefortia pub esc e n s T o u rnefo r t i a rufo s e r ic e a Trema micrantha Urera carocasana Zanthoxylum fagara Seedling Acnistus ellipticus Croton scouleri Psidium galapageium Psidium guajava Psychotria rufipes Scalesia cordata Tournefort i a pub e sc en s Tournefortia rufosericea Trema micrantha Urera caracasana Zanthoxylum fagara H-layer Abutilon depauperatum Altenanthera halimifolia Anredera ranosa Asplenium formosum Asplenium paraemorsum ? Bidens pilosa Blechnum occidentale Blechnum polypodioides Blechum brcwnei Capsicum frutescens Cassia occidentalis Cassia tora Centella asiatica Commerina dtffusa Conyza bonariensis Ctenitis sloanei - 142- Competitive Relationships between Tree Species of Scc/es ia and Introduced Plants (Shimizu) Plot No. Cl C2 C3 C4 C5 No BA No BA No BA No BA No BA Cyperus sp. Desmodium canum Diodia radula Doryopteris pedata Drymaria cordata Epidendrum spicatum Graminae sp. H eliotropium angiospermae Hyptis mutabilis Ichnanthus nemorosus Ipomoea alba Ipomoea nil Justicia galapagana Kalanchoe pinnata Malvastrum conomandelianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Peperomia galapagensis Peperomia petiolata Phoradendron henslovii Physalis pubescens Polypodium dispersum Polypodium tridens Polypodum lanceolatum Pteridium aquilinum Salvia occidentalis Sida rhombifolia Solanum nodifloram Stachytarpheta cayennensis S tic toc ard ia t i I iifol ia Synedrella nodiflora Thelypteris balbisii Verbena townsendii vine sp. Plot No. C6 C7 C8 C9 ClO Altitude (m) 185 22O 22O 22O 330 Plot size (mxm) 10x l0 lOx l0 10x l0 lOx l0 lOX lO Crownheight(m) 7 3 4 5 9 Coverage (/o) Tl-layer 95 100 50 T2-layer 30 20 73 S-layer 5 50 lO 2 l0 H-layer 50 30 80 5 80 No BA No BA No BA No BA No BA T 1-layer Acnistus ellipticus 1 106 Croton scouleri Pisonia floribunda 1 681 Psidium galapageium Psidium guajava 3 244 40 885(25) ―-143-一 Regional VievJs No. 11 1997 Plot Noo C6 C7 C8 C9 C10 No BA No BA No BA No BA No BA Scα Jeslia cOだ ara 9 925 乃 ′e/orrlia′ basc`“ s “ rre““α″〕Icra“ ′乃“α Za“ ′乃oxyル /agara 2 182(58) “ T2¨ layer ∠c“ お′sθ ′J″ ′lic“ S “ Caだlicル cψ乃″crお “ CrarO“ scο ルrli “ Piso“ liaノ θrlib“ ごα “ PsliJ滋 garapagθJ“ 1 6 (1) (3) 16886(6) “ Pslid′ g“ aJaッ α “ 30 126 ““ (52)(639)(23)(567) (1) (6) Scα Jeslia cOrdara 3 176 (1) (20) (1) (6) 乃 g/Orrlig′ bescθ s 5 38 (8) (38) 2 22(3) 乃 ““g/Orrlic m/Osθ“ rlic““ ““ じレじα cαracasα P2α Zα 働oxyル /agara 10 173(47) 1 2 2 363 “ “ S-layer Acnistus ellipticus Capsicum fnttescens Chiococca alba Croton scouleri Pisonia floribunda Pleuropetalum danvinii Psidium galapageium 1 Psidium guajava 1 10 21 Psychotria rufipes Scqlesia cordata 51(1) T ou rn efor tia p s i lo st achy a Tournefortia pubescens T o u r n efo r t i a rufo s e r ic e a Trema micrantha 12 Urera caracasana Zanthoxylum fagara Seedling Acnistus ellipticus Croton scouleri Psidium galapageium Psidium guajava Psychotria rafipes Scalesia cordata Tournefortia pubescens T o u r n efo r t i a rufo s e r ic e a Trema micrantha Urera caracasana Zanthoxylum fagara H-layer Abutilon depauperatum -1名 ― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Plot No. C6 c7 C8 C9 C10 No BA No BA No BA No BA No BA Altenanthera halimifolia 1 Anredera ranosa Asplenium formosum Asplenium paraemorsum ? Bidens pilosa Blechnum occidentale Blechnum polypodioides Blechum brownei Capsicum frutescens Cassia occidentalis Cassia tora Centella asiatica Commerina diffusa Conyza bonariensis Ctenitis sloanei Cyperas sp. Desmodium canum Diodia radula Doryopteris pedata Drymaria cordata Epidendrltm spicatum Graminae sp. Heliotropium angiospermae Hyptis mutabilis Ichnanthus nemorosus Ipomoea alba Ipomoea nil Justicia galapagana Kalanchoe pinnata Malvastntm coromandelianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Peperomia galapagensis Peperomia petiolata Phoradendron henslovii Physalis pubescens Polypodium dispersum Polypodium tridens Polypodum lanceolatum Pteridium aquilinum Salvia occidentalis Sida rhombifolia Solanum nodiflontm Stachytarpheta cay ennensis S t ic toc ard i a til iifol ia Synedrella nodiflora Thelypteris balbisii Verbena townsendii vine sp. -145- Regional Views No. 11 1997 Plot No. CH C12 C13 Altitude (m) 180 180 150 C14 C15 C16 Plot size (m X m) 5× 30 4〉 〈 20 5× 30 3204× 15 350 1ines line340 Crown height (m) 6 5 2.5 7 Coverage (Vo) Tl-layer 30 15 35 70 T}-layer 0 4 2 5 S-layer 30 5 40 10 H-layer 30 60 90 90 No BA No BA No BA No BA Tl-layer Acnistus ellipticus Croton scouleri 3 225 Pisonia floribunda 772 Psidium galapageium 1 28 97 Psidium guajava 6 316 1 29 59 3 123 Scalesia cordata 7 635 3 108 2 146 + Tournefortia pubescens Trema micrantha Zanthoxylum fagara 1 62 T2-layer Acnistus ellipticus Cordia leucophlyctis Croton scouleri Pisonia floribunda Psidium galapageium (1) (3) 2(3) 7(3) Psidium guajava 4 87 3 107 (12) (160) (3) (29) (4) (51) (3)(116) Scalesia cordata (13) (534) (9) (355) (5) (147) Tournefortia pubescens 2 11 6(3) 83(10) To u r n efo r t i a rafo s e r i c e a 2 24 Urea caracasana Zanthoxylum fagara 2(2) 29(50) (2) (36) 13 413 1 14 + S-layer Acnistus ellipticus Capsicum fnttescens Chiococca alba Croton scouleri Pisonia floribunda 2 Pleuropetalum daruinii + Psidium galapageium 1 + Psidium guajava 11 + Psychotria rafipes + Scalesia cordata 153 123 39 十 Tou rn efo rt i a p s ilo s t ac hy a 1 Tournefortia pubescens 4 Tou rn efort i a rufo se ric ea 4 Trema micrantha Urera caracasana Zanthoxylum fagara 9 一-146-― Competitive Relationships between Tree Species of Scclesia and Introduced Plants (Shimizu) Plot No. CH C12 C13 C14 C15 C16 No BA No BA No BA No BA Seedling Acnistus ellipticus Croton scouleri 2 Psidium galapageium 1 Psidium guajava ＋ Psychotria rufipes 十＋ Scalesia cordata Tournefortia pubescens T ou r n efo r t i a rufo s e r i c e a Trema micrantha ＋ Urera caracasana 十 Zanthoxylum fagara H-layer 十 Abutilon depauperatum ＋ Alt e n anthe ra halim ifo li a Anredera ranosa Asplenium formosum Asplenium paraemorsum ? Bidens pilosa 十 Blechnum occidentale Blechnum polypodioides Blechum brownei capsicum frutescens Cassia occidentalis Cassia tora Centella asiatica Commerina diffusa 十 Conyza bonariensis Ctenitis sloanei Cyperus sp. Desmodium canum + Diodia radula + Doryopteris pedata + Drymaria cordata Epidendrum spicatum Graminae sp. H eliotropium angiosPermae Hyptis mutabilis Ichnanthus nemorostts Ipomoea alba Ipomoea nil 十 Justicia galapagana 十 Kalanchoe pinnata M alv as trum c ono m and e lianum Mecardonia dianthea Oxalis corniculata Paspalum coniugatum Peperomia galapagensis Peperomia petiolata Phoradendron henslovii Physalis pubescens + Polypodium dispersum 1 3+ Polypodium tridens -147- Regional Views No。 11 1997 Plot No. Cll C12 C13 C14 C15 C16 No BA No BA No BA No BA Porypαr“ ra“ cω rar“ “ “ PrerlilJJ“ ″7 αg“ lirliP3“ 3233 + sar71ic accだ θra騰 “ 2 + “ Sida ttο b:ル Jlia 3 sara“ “ ο″″ + ““ “"´ SraCり たフ乃θra cりθ θsお 2 + “““ srlicracaだ lila rJJ′ ψ肋 シ ″″JJa“″メοra 2 + “ 動 θ た bα Jbお″ り =お 降rbθP3α ′ο″sθ ごlili vine sp. “ “ Plot No. Dl D2 D3 D4 D5 Altitude(m) 780 780 780 650 550 Plot size(m× m) 10× 10 10× 10 1o× lo lo× lo lo× lo Crown height(m) 4 4 4 5 6 Coverage(%♭ )Tl‐ layer 60 70 1o 70 30 T2‐ layer ― 一一 __ 15 60 S‐layer 30 5 30 20 1o H‐layer 40 75 90 80 70 No BA No BA No BA No BA No BA T1-layer Bursera graveolens 1 670 Croton scouleri 6 112 Opuntia insularia 1 380 Pisonia floribunda Psidium galapageium Psidium guajava 5 181 1 124 1 35 Sapindus saponaria Scalesia cordata 13 998 8 583 4 404 5 584 2 305 Tou rnefortia p ub e sc e n s 2 40 1 8 Zanthoxylum fagara 1 28 T2-layer Bursera graveolens 2 27 Chiococca alba 1 7 Cordia leucophlyctis Cordia scouleri Croton scouleri 8 57 7 70 (10) (126) (14) (168) Pisonia floribunda 1 36 Psidium galapageium 1 9 5 52 Psidium guajava 1 13 Scalesia cordata 9 154 (1) (47) Tou rneforti a p silos t achy a Tournefort i a pub e sc e n s 2 8 To u r n efo r t i a rafo s e r ic e a 1 5 4 38 Zanthoxylum fagara 2 9 2 35 S-layer Altenanthera echinocephara 一-148-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Dl D2 D3 D4 D5 No BA No BA No BA No BA No BA Baccharis gnidiifolia 1 5 Bursera graveolens 1 Capsicum fnttescens Cassia picta 1 Chiococca alba 1 4 1 Cordia leucophlyctis 21 4(1) 2(1) 1 Cordia scouleri Croton scouleri 37(2) 18(3) Danviniothamnus lancifulius 24 Danv iniothamnus tenuifulius Gossypium barbadense v. danvinii I Opuntia insularis Pisonia floribunda 2 Psidium galapageium 5 Psidium guajava 1 lo Scalesia cordata 7 3 Tournefortia psilostachya Tournefortia pubescens 5 1(1) 3 T o u r n efo r t i a rafo s e r ic e a 2 1 (1) 3 Zanthoxylum fagara 7 3 12 Seedling Baccharis gnidiifolia 1 Cordia leucophlyctis Croton scouleri D anv in io th amnu s t e nu ifo liu s Gossypium barbadense v. darwinii Psidium guajava T o u rn efo r t i a rufo s e ri c e a Zanthoxylum fagara H-layer Abutilon depauperatum Acalypha parvula Adiantum henslovianum Ageratum conyzoides Altenanthera filifolia A I t e n an t he ra h ali m ifo li a Anthephora hermaphrodita Apium leptophyllum Bidens riparia Blainvillea dichotoma Blechum brownei Boutelona disticha Brickellia diffusa Centella asiatica Chrysanthellum pusillum Cissampelos pareira Cisszs sicyoides Clotalaria incana Clotalaria pumila Commerina diffusa Commicarpus tuberosus ' Conyza bonariensis 一-149-― Regional Views No. I I 1997 Dl D2 D3 D4 D5 No BA No BA No BA No BA No BA Ctenitis sloanei l Cyperus brevifolius Cyperus sp. 1 Desmodium canum Desmodium procumbens Digitalia horizontalis Digitaria adscendens Diodia radula Doryopteris pedata Eleocharis sp. Galactia tenuiflora H eliotropium angiospermum Hyptis mutabilis Ipomoea triloba M alv astrum coromand erianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Phoradendron henslovii Pityrcgramma calomelanos Plumbago scandens Polypodium dispersum Polypodium tridens Pteridium aquilinum Rhynchosia minima Salvia occidentalis Scoparia dulcis Sida hederifolia Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus Stachytarpheta cayennensis Synedrella nodiflora Trachypteris pinnata Verbena townsendii Plot No. D6 D7 D8 D9 D10 Altitude (m) 420 840 840 810 780 Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 10× 10 Crown height (m) 6 3 3 3 5 Coverage (Vo) Tl-layer 75 T2-layer 鵜 30 3 60 S-layer 5 20 5 50 5 H-layer 75 80 100 80 90 No BA No BA No BA No BA No BA T1-layer Bursera graveolens Crcton scouleri 2 74 Opuntia insularia Pisonia floribunda Psidium galapageium Psidium guajava 4 330(7) -150- Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu) D6 D7 D8 D9 D10 No BA No BA No BA No BA No BA Sapindus saponarta Scalesia cordata 5 569 Tournefortia pubescens Zanthoxylum fagara 1 70 TZ-layer Bursera graveolens Chiococca alba Cordia leucophlyctis 1 12 Cordia scouleri 2 17 Croton scouleri Pisonia floribunda Psidium galapageium Psidium guajava 4 162 Scalesia cordata 24 2594 (2) (270) (1) (43) Tourn efor tia p s ilo s t achy a 1 4 Tournefortia pubescens 2 44 2 161 Tournefo rt i a rufo s eric e a 2 21 1 75 1 71 Zanthoxylum fagara 10 115 1 65 S-layer Altenanthera echinocephara 31 Baccharis gnidiifolia 2 Bursera graveolens Capsicum frutescens Cassia picta 6(12) Chiococca alba Cordia leucophlyctis 2 13 Cordia scouleri Croton scouleri D arw in io th amnu s I anc ifol iu s D arw in io th am nu s t enuift liu s 1 20 11 Gossypium barbadense v. darutinii Opuntia insularis 1 Pisonia floribunda Psidium galapageium 1 Psidium guajava 3 Scalesia cordata 1 43 4(1) Tourn eforti a p s ilo s t a c hy a Tournefo rt i a pub e sc en s Tou rnefort i a rufo se rtc e a 1 1 Zanthoxylum fagara 11 Seedling Baccharis gnidiifolia Cordia leucophlyctis Crcton scouleri D arut in io th amnu s t enuifo liu s Gossypium barbadense v. darutinii Psidium guajava T o u r n efo r t i a rufo s e ric e a Zanthoxylum fagara -151- Regional Views No.11 1997 D6 D7 D8 D9 D10 No BA No BA No BA No BA No BA H-layer Abutilon depauperatum 2 Acalypha pamula Adiantum henslovianum Ageratum conyzoides Altenanthera filifolia A I t e nanthe ra halim ifol ia Anthephora hermaphrod ita Apium leptophyllum Bidens riparia Blainvillea dichotoma Blechum brcwnei Boutelona disticha Brickellia dffisa Centella asiatica Chrysanthellum pusillum Cissampelos pareira Cissus sicyoides Clotalaria incana Clotalaria pumila Commerina difusa Commicarpus tuberosus Conyza bonariensis Ctenitis sloanei Cypents brevifolius Cyperus sp. Desmodium canum Desmodium procumbens Digitalia horizontalis Digitaria adscendens Diodia radula Doryopteris pedata Eleochafls sp. Galactia tenuiflora Heliotropium angiospermum Hyptis mutabilis Ipomoea triloba M alv astrum coromanderianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Phoradendron henslovii Pityrogramma calomelanos Plumbago scandens Polypodium dispersum Polypodium tridens Pteridium aquilinum Rhynchosia minima Salvia occidentalis Scoparia dulcis Sida hederifolia Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus ―-152-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) D6 D7 D8 D9 D10 No BA No BA No BA No BA No BA S t achy t arph e ta c ay e nn e n s is Synedrella nodiflora Trachypteris pinnata Verbena townsendii Plot No. DH D12 D13 D14 D15 Altitude (m) 730 715 670 770 780 Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 10× 10 Crown height (m) 5541。 3 2.8 Coverage (Vo) Tl-layer 60 20 -― 一― T2-layer 15 40 一- 30 S-layer 20 30 1 15 H-layer 70 70 90 90 No BA No BA No BA No BA No BA T1-layer Bursera graveolens Croton scouleri Opuntia insularia Pisonia floribunda Psidium galapageium Psidium guajava 5 107 Sapindus saponaria Scalesia cordata 14 904 7 698 Tournefort i a pub e sc e n s Zanthoxylum fagara TZ-layer Burcera graveolens Chiococca alba Cordia leucophlyctis Cordia scouleri Croton scouleri Pisonia floribunda Psidium galapageium Psidium guajava 1 19 1 33 3 768 Scalesia cordata 8 145 9 131 (1)(23) Tourn efort i a p silost achy a Tournefortia pubescens 2 33 T o ur n efo r t i a rufo s e ric e a 1 8 Zanthoxylum fagara S-layer Altenanthera echinocephara Baccharis gnidiifolia Bursera graveolens Capsicum frutescens Cassia picta Chiococca alba Cordia leucophlyctis Cordia scoulert Croton scouleri ―-153-― Regional Views No. 11 1997 DH D12 D13 D14 D15 No BA No BA No BA No BA No BA Darwiniothamnus lancifolius 20 D anv iniothamnus tenuifolius Gossypium barbadense v. darwinii Opuntia insularis Pisonia floribunda Psidium galapageium Psidium guajava 3 1 78(2) 1 22 Scalesia cordata 1 6 Tournefortia p silostachy a Tournefort ia p u b e sc e n s Tou r nefor t i a rufo s e ric e a Zanthoxylum fagara Seedling Baccharis gnidiifolia Cordia leucophlyctis Crcton scouleri D arut in io th am nu s t enuifo I iu s Gossypium barbadense v. daruinii Psidium guajava Tou rn efo rt i a rufo se ric e a Zanthoxylum fagara H-layer Abutilon depauperatum Acalypha pamula Adiantum henslovianum Ageratum conyzoides Altenanthera filifolia Altenanthera halimifolia Anthephora hermaphrodita Apium leptophyllum Bidens riparia Blainvillea dichotoma Blechum brownei Boutelona disticha Brickellia diffusa Centella asiatica Chrysanthellum pusillum Cissampelos pareira Cisszs sicyoides Clotalaria incana Clotalaria pumila Commerina diffusa Commicarpus tuberosus Conyza bonariensis Ctenitis sloanei Cyperus brevifolius Cyperus sp. Desmodium canum Desmodium procumbens Digitalia horizontalis Digitaria adscendens 1 Diodia radula 1 ―-154-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimi"u) DH D12 D13 D14 D15 No BA No BA No BA No BA No BA Doryopteris pedata Eleocharus sp. Galactia tenuiflora H eliotropium angiosPermum Hyptis mutabilis Ipomoea triloba Malvastntm coromanderianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Phoradendron henslovii Pityrogramma calomelanos Plumbago scandens Polypodium dispersum Polypodium tridens Pteridium aquilinum Rhynchosia minima Salvia occidentalis Scoparia dulcis Sida hederifolia Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus Stachytarpheta cayennensis Synedrella nodiflora Trachypteris pinnata Verbena townsendii Plot No. D16 D17 D18 D19 D20 Altitude (m) 700 730 460 450 770 Plot size (m X m) 10× 10 5)く 30 1ine line line 5 Crown height (m) 4。 5 4。 5 3.5 7 3。 Coverage (Vo) TlJayer - 5 T2-layer 80 50 S-layer 5 20 H-layer 60 95 No BA No BA T I -layer ＋ graveolens Bursera ＋ Croton scouleri Opuntia insularia 十 Pisonia floribunda ＋ Psidium galapageium guajava Psidium ＋＋ Sapindus saponaria Scalesia cordata 7 926 Tournefortia pub escens Zanthoxylum fagara T2‐ layer J“ rsθ ttα grα ッθOた■s 5 24 2 35 Chliocοccα αJbα 一-155-― Regional Views No。 11 1997 D16 D17 D18 D19 D20 No BA No BA Cordia leucophlyctis (1) (2) Cordia scouleri Croton scouleri 45 654 29 186 + (7) (134) (9) (87) Pisonia floribunda Psidium galapageium Psidium guajava 1 5 + ＋ Scalesia cordata 4 183 5 95 + ＋ Tou rneforti a p s i lo s t achy a Tournefo rti a p ub e sc en s 4 97 Tou r nefo rt i a rufo se ric e a 1 2 Zanthoxylum fagara S-layer Altenanthera echinocephara Baccharis gnidiifolia Bursera graveolens Capsicum frutescens Cassia picta 1 Chiococca alba 1 2 Cordia leucophlyctis 2 7 Cordia scouleri Croton scouleri 43(5) 37 D anv in ioth am nu s I an c ifo I iu s 3 Dany iniothamnus tenuifolius Gossypium barbadense v. danyinii 2 Opuntia insularis 1 Pisonia floribunda Psidium galapageium Psidium guajava 3 Scalesia cordata 1 Tournefort ia p s i lo stac hy a Tourn efort i a pub e sc e n s 3 Tou r nefort i a rufo s e ric e a 5 Zanthoxylum fagara 15 Seedling Baccharis gnidiifolia I 1 Cordia leucophlyctis 1 Croton scouleri 2 Dan+tiniothamnus tenuifolius Gossypium barbadense v. danyinii I 1 Psidium guajava 十 Tournefortia rufoseric e a Zanthoxylum fagara H-layer Abutilon depauperatum Acalpha pamula Adiantum henslovianum Ageratum conyzoides Altenanthera filifolia Altenanthera halimifolia Anthephora hermaphrodita 2 ―-156-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimbu) D16 D17 D18 D19 D20 No BA No BA Apium leptophyllum Bidens riparia Blainvillea dichotoma Blechum brownei Boutelona disticha Brickellia diffusa Centella asiatica Chrysanthellum pusillum Cissampelos pareira Cisszs sicyoides Clotalaria incana Clotalaria pumila Commerina diffusa Commicarpus tuberosus Conyza bonariensis Ctenitis sloanei 十 Cyperus brevifolius Cyperus sp. Desmodium canum Desmodium procumbens Digitalia horizontalis Digitaria adscendens Diodia radula Doryopteris pedata Eleocharis sp. Galactia tenuiflora Heliotropium angiospermum Hyptis mutabilis Ipomoea ffiloba Malvastrum conomanderianum Mecardonia dianthea Oxalis corniculata Paspalum conjugatum Phoradendron henslovii Pityrogramma calomelanos Plumbago scandens + Polypodium dispersum ＋ 十 Polypodium tridens Pteridium aquilinum 十 Rhynchosia minima Salvia occidentalis Scoparia dulcis Sida hederifolia + Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus Stachy t arpheta c ay ennen s is Synedrella nodiflora Trachypteris pinnata Verbena townsendii ―-157-― Regional Views No. I | 1997 Plot No. El E2 E3 E4 Altitude (m) 570 570 610 810 Plot size (m X m) 10× 10 10× 20 10× 20 10× 10 Crown height (m) 4 5 5 5 Coverage (Vo) Tl-layer 25 20 25 T2-layer 10 20 10 10 S-layer 60 30 15 20 H-layer 90 95 100 100 No BA No BA No BA No BA T1-layer Bursera graveolens 1 1280 Scalesia microcephala 1 129 Trema micrantha 1 791 1 630 T}-layer Bursera glabeolens 1 6 1 4 Cordia lutea Cordia revoluta Psidium galapageium 1 50 Scalesia microcephala 5 130 3 174 4 142 (2) (72) Scutia pauciflora Tournefortia pub e sc en s 1 11 2 40 Trema micrantha 1 26 2 51 3 42 Walteria ovata Zanthoxylum fagara 2 111 S-layer Baccharts gnidiifolia 3 2 Bursera graveolens 2 1 Cassia picta 1(3) 13(3) 9(6) Castela galapageia Chamaecyce viminea Chiococca alba Cordia andesonii 1 Cordia leucophlyctis D anv in io th am nu s t e nuifo lius Lantana peduncularis Macraea laricifolia 21 Psidium galapageium Scalesia microcephala 34 (8) Scutia pauciflora Tourn efort ia p s ilo s t a chy a Tournefortia pub escen s Tou r n efo rt i a rufo s e r ic e a Trema micrantha 1 Walteria ovata 56(1) 32(4) Zanthoxylum fagara Seedling Cordia leucophlyctis Psidium galapageium Scalesia microcephala Tou r nefort i a rufo se rric e a ―-158-一 Colmpetitive Relationships between Tree Species of Scα reslic and lntroduced Plants(ShilniZu) Plot No. El E2 E3 E4 No BA No BA No BA No BA NQJ′θrlia οッαra l Zα Йoxyル /ar“ “ “ Herb Acalypha pamula Adiantum henslovianum Altenanthera halimifolia Amaranthus gracilis Anthephora hermaphrodita 2 Aristida divulsa Aristida repens Bidens riparia Blainvillea dichotoma 4 Boutelona disticha 3 Cenchrus platyacanthus 3 Centella asiatica Chamaecyce punctulata Commerina diffusa Crotalart pumila Crotalaria incana 2 Cuscuta gymnocarpa 2 Cyperus confertus Desmodium glabrum 3 Digitaria adscendens Diodia radula Euphorblo sp. Fleurya aestuans Heliotropium angiopterinum I Hyptis rhomboidea 3 Ipomoea nil Ipomoea triloba 2 Mentzelia aspera Paspalum conjugatum Pennisetum pauperum Phoradendron henslovii Physalis pubescens Polygala galapagoensis Porophyllum ruderale Pteridium aquilinum Rhynchosia minima 4 Salvia occidentalis Scoparia dulcis Sida hederifolia Sida rhombifolia Sida salvifolia Sida spinosa 3 Sonchus oleraceus Sporobolus indicus Stylosanthes sympodialis 2 Synedrella nodiflora Tephrosia decumbens 2 Uniola pittieri Zornia piurensis I 一-159-― Regional Views No. 11 1997 Plot No. E5 E6 E7 E8 Altitude (m) 810 790 1070 370 Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 Crown height (m) 3。 5 3.5 3 6 Coverage (Vo) Tl-layer 35 50 T2-layer 2 15 S-layer 20 60 20 15 H-layer 100 100 90 90 No BA No BA No BA No BA T1-layer Bursera graveolens 5 801 Scalesia microcephala Trema micrantha T2-layer Bursera glabeolens Cordia lutea 2 89 Cordia revoluta Psidium galapageium Scalesia microcephala 1 93 4 185 (1) (43) Scutia pauciflora 1 13 Tourn efortia p ub e sc en s Trema micrantha Walteria ovata Zanthoxylum fagara S-layer Baccharts gnidiifolia Bursera graveolens Cassia picta Castela galapageia Chamaecyce viminea Chiococca alba Cordia andesonii Cordia leucophlyctis D arw in ioth amnu s t e nuifo I iu s Lantana peduncularis Macraea lartcifolia Psidium galapageium Scalesia microcephala 16 197 42 138 (2) (79) (12) (2) Scutia pauciflora Tournefortia p silostachy a 1 Tournefortia pub e scen s 3 24 4 83 To u r n efo r t i a rufo s e ric e a Trema micrantha Walteria ovata Zanthoxylum fagara 1 19 Seedling Cordia leucophlyctis Psidium galapageium Scalesia microcephala Tournefortia rufoserricea ―-160-― Competitive Relationships betwOen Tree Species of Scaraslic and lntroduced Plants(ShimiZu) Plot No◆ E5 E6 E7 E8 No BA No BA No BA No BA フИarた rlia。ッαra Zα oxyル /aga″ 1 "Й “ Herb Acalypha pamula Adiantum henslovianum Alt e n an the ra halimifol i a Amaranthus gracilis Anth ephora h e r m aphrod it a Aristida divulsa Aristida repens Bidens riparia Blainvillea dichotoma Boutelona disticha C e nchru s p I aty ac anthu s Centella asiatica Chamaecyce punctulata Commerina diffusa Crotalari pumila Crotalaria incana Cuscuta gymnocarpa Cyperus confertus Desmodium glabram Digitaria adscendens Diodia radula Euphorbic sp. Fleurya aestuans Heliotropium angiopterinum Hyptis rhomboidea Ipomoea nil Ipomoea triloba Mentzelia aspera Paspalum conjugatum Pennisetum pauperltm Phoradendron henslovii Physalis pubescens Polygala galapagoensis Porophyllum ruderale Pteridium aquilinum Rhynchosia minima Salvia occidentalis Scoparia dulcis Sida hederifolia Sida rhombifolia Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus Stylosanthes sympodialis Synedrella nodiflora Tephrosia decumbens Uniola pittieri Zornia piurensis -161- Regional Views No. l1 1997 Plot No. E9 E10 Ell E12 Altitude (m) 340 240 470 990 Plot size (m X m) 10× 10 10× 10 5× 20 line 20 Crown height (m) 6 6 7 2 Coverage (Vo) Tl-layer 50 60 30 T2-layer 20 15 5 S-layer 30 20 60 H-layer 90 90 85 No BA No BA No BA T1-layer Burcera graveolens 2 977 3 889 1 832 Scalesia microcephala Trema micrantha 1 59 T2-layer Bursera glabeolens 10 154 2 69 Cordia lutea Cordia revoluta 1 2 Psidium galapageium Scalesia microcephala 3 123 4 82 Scutia pauciflora Tournefortia pub escens 1 5 Trema micrantha 1 13 Walteria ovata 2 19 Zanthoxylum fagara S-layer Baccharis gnidiifolia 11 28 Bursera graveolens Cassia picta 1 Castela galapageia 1 Chamaecyce viminea 24 6 Chiococca alba 1 Cordia andesonii 十 Cordia leucophlyctis 2 1 4 ＋ Darutiniothamnus tenuifolius I 1 Lantana peduncularis 2 17 1 Macraea laricifolia 7 35 Psidium galapageium + Scalesia microcephala 4 1 3 Scutia pauciflora 1 Tournefo rt i a p s ilo st achy a 1 十＋ Tournefo rti a p ub e sc en I 2 T ou r n efo r t i a rufo s e r ic e a 1 Trema micrantha 2 Walteriaovata 3 7 20 24 Zanthoxylum fagara Seedling Cordia leucophlyctis Psidium galapageium Scalesia micrccephala I Tournefortia rufoserricea 一-162-― Competitive Relationships between Tree Species of Sca/esia and Introduced Plants (Shimizu) Ell E12 Plot No. E9 E10 No BA No BA No BA Walteria ovata Zanthoxylum fagara Herb Acalypha pamula Adiantum henslovianum A I t e n an thera halimifoli a Amaranthus gracilis Anthephora hermaphrodita Aristida divulsa Artstida repens Bidens riparia Blainvillea dichotoma Boutelona disticha C e nchru s p laty ac an thu s Centella asiatica Chamaecyce Punctulata Commerina diffusa Crotalari pumila Crotalaria incana Cuscuta gymnocarPa Cyperus confertus Desmodium glabrum Digitaria adscendens Diodia radula Euphorbfa sP. Fleurya aestuans H eliotrop iutn angioPterinum Hyptis rhomboidea Ipomoea nil Ipomoea triloba Mentzelia asPera Paspalum coniugatum Pennisetum PouPentm Phoradendron henslovii Physalis pubescens Polygala galapagoensis Porophyllum ruderale Pteridium aquilinum Rhynchosia rninima Salvia occidentalis Scoparia dulcis Sida hederifolia Sida rhombifolia Sida salvifolia Sida spinosa Sonchus oleraceus Sporobolus indicus Stylosanthes sy mPodialis Synedrella nodiflora Tephrosia decumbens Uniola Pittieri Zornia piurensis 一-163-一 RegiOnal Views No。 11 1997 Plot No. Fl F2 F3 F4 Altitude (m) 310 310 330 3∞ Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 Crown height (m) 6 6 5 8 ` Coverage (Vo) Tl-layer 75 15 75 100 T2-layer 10 80 20 0 S-layer 30 410 30 10 H-layer 1 100 5 5 No BA No BA No BA No BA T1-layer Croton scouleri Pisonia floribunda Psidium guajava 1 13 Scalesia pedunculata 14 835 2 251 15 837 29 1618 T2‐ layer Cli′ ″s″ θ′ra “ Cli′ ″s sp。 1 5 3 39 creЮde.ご″ οJra ““ Caだlia αだasθ ″ 1 5 (1) (8) (1) (12) “ CaだJα たcψλryc麻 2 33 (1) (16) CrOra“ sca““ルrli 6 70 9 179 7 106 (1) (13) (4) (59) (3) (95) (4) (55) Rso"liaメοrlib“ ごα l 181 (167) “ PslilJliz″2g“ aJaッ α 1 24 23 375 3 44 (1) (59) scareslilc Pθ ごc“ raた 5 36 2 31 “ “ (5) (87) (4) (171) (3) (72) (5) (227) 乃 ′0わ rrlia′ besce“ s ““ Zα 働り ′ ragara“ 1 5 7 51 3 61 “ ““ S‐layer Capraria biflora Chiococca alba Citnts limetta Citras sp. 1 Clerodendntm molle 3 6 1 Cordia andesonii 2 1 Cordia leucophlyctis 6 4 Croton scouleri 13(3) 4(1) 17(3) 33(3) Danviniothamnus tenuifolium 15 11(5) Lantana camara 29 24 1 4 Macraea laricifolia 4 11 Pisonia floribunda 1 Psidium guajava 4 23(1) 11(1) Psychotria angustata Scalesia pedunculata Tou rn efo rt ia pub e sc e n s T o u r n efo r t i a rufo s e r ic e a Zanthoxylum fagara 7 20(1) Seedling Capraria biflora Citrus limetta Clerodendntm molle Croton sbouleri ―-164-― Competitive Relationships between Tree Species of Scclesia and Introduced Plants (Shimi"u) Plot No. Fl F2 F3 F4 No BA No BA No BA No BA + D arut in ioth am nu s t enuifoliu s Macraea laricifolia Psidium guajava 十 Scalesia pedunculata 十 Zanthoxylum fagara 十 H-layer Abutilon depauperatum Asplenium formosum Blechun brownei Centella asiatica Ctenitis sloanei Cyperus sp. Diodia radula Doryopteris pedata Galactia striata Graminae sp. H eliotrop ium angio sP ermum Hyptis mutabilis Kalanchoe pinnata M alv astrum c o ro m and e lianu m Oxalis corniculata Passiflora edulis Peperomia galapagensis Phoradendron henslovii Plumbago scandens Polypodium trtdens Pseudelephatopus sPicatus Salvia occidentalis Sida hederifolia Sida rhombifolia Stachytarpheta caYennbnsis Tillandsia insularis 1 3 Trachypteris pinnata? 4 3 Plot No. F5 F6 F7 F8 Altitude (m) 380 370 330 3∞ Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 Crown height (m) 6 9 9 5 Coverage (Vo) Tl-layer 95 70 100 70 T2-layer 20 20 80 2 S-layer 30 10 2 100 H-layer 30 50 3 1 No BA No BA No BA No BA T1-layer Crcton scoulert Pisonia flortbunda 1624 Psidium guajava Scalesia pedunculata 14 1850 1347 2530 850 T2-layer Citrus limetta 9(1)513(19) 一-165-一 Regional Views No.11 1997 Plot No. F5 F6 BA F7 F8 No BA No BA No No BA clir″s sp◆ creraル ご ″ ο Jル 1 ll “ ““ Co′ ゼJα α 己es()“ lii (1) (19) “ Coガ滋ル c″力″Crぉ 2 70 2 17 “ CrOrO“ scο ルl rli 5 45 7 127 1 33 “ (1) (18) Piso“ lilaノ οrlib“ ごα “ PslilJJ“ g“ りαッα 5 68 “ (2) (52) (2) (33) scareslila′ θごc“ たた 1 8 ““ (4) (343) (2) (374) (2) (63) (4) (164) ■,“ g/orrlig′ わascθ s 2 57 1 12 24 Zα “oxyJ“ “ “ 漏 /agara 1 “ “ S-layer Capraria btflora Chiococca alba Citrus limetta Citrus sp. Clerodendrum molle 4 Cordia andesonii Cordia leucophlyctis 4 Croton scouleri 35 4(2) D anv in io th am nu s t e nu ifol iu m Lantana camara 33(3) Macraea laricifolia 1 6 Pisonia floribunda Psidium guajava 8(1) 21 4 Psychotria angustata 1 Scalesia pedunculata 1 36 Tournefortia pubescens 1 1 Tou r n efo r t i a rafo s e r ic e a Zanthoxylum fagara 6 4 Seedling Capraria brflora 2 2 Citrus limetta Clerodendntm molle Croton scouleri 2 D anv in io th am nus te nu ifo I iu s Macraea laricifolia Psidium guajavo 2 Scalesia pedunculata 2 Zanthoxylum fagara H-layer Abutilon depauperatum Asplenium formosum Blechun brownei Centella asiatica Ctenitis sloanei Cyperus sp. Diodia radula Doryopteris pedata ―-166-― Competitive Relationships between Tree Species of Scalesia and Introduced Plants (Shimizu) Plot No. F5 F6 Yl F8 No BA No BA No BA No BA Galactia striata 2 Graminae sp. Heliotropium angiospermum Hyptis mutabilis Kalanchoe pinnata MalY^strum corcmandelianum 0xalis corniaiau 2 2 Passiflora edulis Pepercmia gahpagensis 2 Phoradendron hewlovii Plumbagoscandens 2 4 2 Polypodium tridens I I Pseudelephatopus spicatus Salviaoccidennlis | 2 I Sida hederifolia Sida rhombi.folia Suchytarphen cayennbnsis 2 Tillandsia insularis Trachypteris pinnan? Plot No. F9 F10 Fll F12 Altitude (m) 280 370 340 430 Plot size (m X m) 10× 10 5× 20 line line Crown height (m) 5 9 4 3 Coverage (Vo) Tl-layer 50 T2-layer 15 50 S-layer 80 20 H-layer 2 20 No BA No BA T1-layer Croton scouleri 4 328 Pisonia floribunda 1 609 Psidium guajava Scalesia pedunculata 1 191 T2‐ layer Cli′ ″s″ θ′ra “ Cli′ ]昭 s sp. 1 236 crer。 ルご″ ο′ル “““ Co′ ゼlia α ご賀ο JJ “ “ Coだliaル coPカ タc′ お 1(1) 13(13) + “ crOra“ scο ルrli 2 26 8 292 + “ (4) (187) Piso“ Jα ノοrlib“ ごα 2 30 + “ PsliJJ“ ″ g“ りαッα Scalesia pedunculata 3 37 7 123 + Tournefortia pubescens 5( I ) 309(90) Zanthoxylum fagara 一-167-― Regional Views No。 11 1997 Plot No. F9 F10 Fll F12 No BA No BA S-layer Capraria biflora Chiococca alba Citrus limetta Citrus sp. 十 十 Clerodendntm molle 4 Cordia andesonii Cordia leucophlyctis ＋ ＋ Croton scouleri 1 D arw inioth amnu s tenuifolium 十 Lantana camara 43(4) ＋ Macraea laricifolia ＋ 十 Pisonia floribunda Psidium guajava 1 Psychotria angustata Scalesia pedunculata 10 Tournefortia pub e sc ens T o u r n efo r t i a rufo s e r ic e a Zanthoxylum fagara 1 Seedling Capraria biflora Citnts limetta Clerodendrum molle Croton scouleri D any in ioth amnu s t enuifo I ius Macraea laricifolia Psidium guajava Scalesia pedunculata Zanthoxylum fagara H-layer Abutilon depauperatum I Asplenium formosum Blechun brownei Centella asiatica Ctenitis sloanei Cyperus sp. Diodia radula Doryopteris pedata Galactia striata 2 Graminae sp. H eliotropium angiospermum Hyptis mutabilis Kalanchoe pinnata Malvastrum conomandelianum 3 Oxalis corniculata Passiflora edulis Peperomia galapagensis Phoradendron henslov ii Plumbago scandens Polypodium tidens 十 一-168-― Competitive Relationships between Tree Species of Sbclesia and Introduced Plants (Shimi"u) Plot No. F9 F10 Fll F12 No BA No BA Pseudelephatopus spicatus Salvia occidentalis Sida hederifolia Sida rhombifulia S t achy t arph e t a c ay e nn b n sis Tillandsia insularis Trachypteris pinnata? Plot No. SCl IBal IBa2 IBbl Altitude (m) 10 5 5 50 Plot size (m X m) 10× 10 10× 10 10× 10 1 Crown height (m) 5。 5 6 3。 5 10× 10 Coverage (Vo) Tl-layer 15 50 T2-layer 25 10 2 S-layer 鵜 25 15 H-layer “20 2 5 20 No BA No BA No BA No BA Tl‐ layer J“ rscra gravω ル s 1 243 6 861 “ の rlia θcλ lios v。 ′θr“お 1 272 ““ “ T2-layer Bursera graveolens 1 24 1 11 Croton scouleri 4(2) 29(28) Jasminocereus thouarsii v. touarsii Opuntia echios v. gigantea 3 623 Opuntia echios v. inermis (1) (177) Piscidia carthagenensis 1 19 Scalesia afinis 1 39 2 46 Tournefortia psilostachy a 1 1 Tournefortia pubescens 1 17 Zanthoxylum fagara 3 94 S-layer Acasia rontdiana Bursera glaveolens Capraria peruviana Castela galapageia 1 Chamaesyce viminea Chiococca alba 2 Cordia andesonii 16 Cordia lutea 1 Cordia revoluta Crcton scouleri 7(1) D anv in ioth am nu s t enuifoliu s 1 Dodonaena viscosa Lantana camara Lantana peduncularis Lecoc arpus p innatifidus Opuntia echios v. inermis Opuntia insularis ―-169-― Regional Views No. I t 1997 Plot No. SCl IBal IBa2 IBbl No BA No BA No BA No BA Sarcostema angustissima 10 Scalesia affinis 5(1) 5(1) Scutia pauciflora Tournefortia psilostachy a 2 Vallesia galbra Walteria ovata 4 Seedling Dodonaea viscosa + Macraea laricifolia 十 Scalesia afinis + Walteria ovata + H-layer Altenanthera filifolia 3 Artstida divulsa 4 Blainvillea dichotoma Boehaavia erecta Chamaecyce punctulata 2 Commicafpus tuberosus Cyperus andersonii Euphorbia tircanii 1 Galactia striata ? Ipomoea hair Ipomoea triloba Mentzelia aspera Merremia aegyptica Momordia charantia Pasiflora foetida Plumbago scandens Polygala galapagoensis Porophyllum ntderale Rhynchosia minima Sarcostemma anustissima S ty los anth e s sy rnpod iale s Plot No. IBb2 IBb3 IBb4 FLl Altitude (m) 100 130 190 3 Plot size (m X m) 10× 10 10× 10 10× 10 10× 10 Crown height (m) 3.5 2。 4 3 6 Coverage (Vo) Tl-layer 25 T2-layer 2 1 30 3 S-layer 25 15 30 30 H-layer 30 30 430 30 No BA No BA No BA No BA Tl-layer Bursera graveolens 8 Opuntia echios v. inermis “ T2-layer Burcera graveolens 1 262 Crcton scouleri “ ―-170-― Competitive Relationships between Tree Species of Scclesia and Introduced Plants (Shimizu) FLl Plot No. IBb2 1Bb3 1Bb4 No BA No BA No BA No BA Jasminocereus thouarsii v. touarsii 1 663 Opuntia echios v. gigantea Opuntia echios v. inermis Piscidia carthagenensis Scalesia ffinis Tournefortia p silostachy a Tournefortia pub escen s Zanthoxylum fagara S-layer Acasia rorudiana Bursera glaveolens 11 2 Capraria peruviana Castela galapageia 1 Chamaesyce viminea 42 2(1) Chiococca alba Cordia andesonii Cordia lutea Cordia revoluta Croton scouleri D arut iniothamnus tenuifolius Dodonaena viscosa Lantana camara Lantana peduncularts 13 L ecoc arpus p innatifidus Opuntia echios v. inermis Opuntia insularis 1 Sarcostema angustissima 2 Scalesia ffinis 10 9(1) Scutia pauciflora T ournefort i a p s ilo stachy a Vallesia galbra Walteria ovata 14 Seedling Dodonaea viscosa Macraea laricifolia Scalesia afinis Walteria ovata H-layer Altenanthera filifolia Aristida divulsa Blainvillea dichotoma Boehaavia erecta Chamaecyce punctulata Commicafpus tuberosus Cyperus andersonii Euphorbia tircanii Galactia striata? Ipomoea hair Ipomoea triloba Mentzelia aspera Merremia aegyptica ―-171- Regional Views No。 11 1997 Plot No. 1Bb2 1Bb3 1Bb4 FLl No BA No BA No BA No BA Momordia charantia Pasiflora foetida Plumbago scandens Polygala galapagoensis Porophyllum ruderale Rhynchosia minima Sarcostemma anustissima Stylosanthes sympodiales ―-172-―