A Comparison of Two Types of Mediterranean Scrub in Israel And

A Comparison of Two Types of Mediterranean Abstract: Matorral/chaparral and phrygana/ 1 coastal sage vegetation types of Israel and Cali- Scrub in Israel and California fornia exhibit major differences in life form spectra, physiognomy, species richness, fire adap- tations, spinescence, and leaf traits. In some Avi Shmida and Michael Barbour2 cases it is possible to correlate such differences in climate, geologic history, soil, fire frequency, and human history. There seems to be only a superficial degree of convergence between comparable mediterranean types of vegetation in the two areas. A mediterranean climate--hot, dry summer and field studies conducted in Southern California cool, wet winter (Trewartha 1954, Flohn 1969)-- and Israel from 1977 - 1980 by the author and Dr. occurs in at least five widely scattered regions Robert Whittaker. Samples were taken along cli- of the world: the Mediterranean region itself, matological gradients from various vegetation between Europe and Africa; the Pacific Coast of types in each of the mediterranean ecosystems. North America, from Oregon to northern Baja Cali- fornia; the Cape Region of South Africa; certain On each site plots of 1/10th hectare (20x50 m= coastal portions of South and West Australia; and 1 dunam) were marked and all sampling was carried the central Chilean coast. As summarized well by out in these plots. The tenth-hectare size was Raven (1971), "Plant associations of the five chosen as being large enough to represent the regions. are extremely similar both in their vegetation adequately but not too large for effi- physiognomy and in the morphology and physiology cient sampling of all vascular plant species. of the constituent plants. dominated by low, The samples were taken at the peak of the spring evergreen, sclerophyllous trees and with short blooming. Direct visual estimation of plant thick trunks and twisted rigid often spreading coverage was used to give relative importance branches." Since the seminal work by Schimper value for species. Detailed plant presence and (1903), most studies of mediterranean vegetation covers were also recorded in ten duplicate quad- have emphasized the degree of convergence (Specht rats along a transect of ten 1 x 1 m squares. The 1969, Naveh 1967, Cody and Mooney 1978, Ashman percentage of rocks, stones and total plant cover 1973). Robert Whittaker had been intensively and percentage of ground cover of all perennial studying southern hemisphere examples until his species were estimated. recent, untimely death (Whittaker et al. 1979, Naveh and Whittaker 1980). On each plant species sampled, the following parameters were recorded: number of species; In this study, I shall compare mediterranean coverage estimation, growth form and phenology. vegetation as found in California and Israel only, Detailed analyses of different species of this defining the mediterranean regions of each accord- study have been published or are now in the pro- ing to Raven (1971) and Zohary (1973). (Mediter- cess of being summarized (Shmida and Whittaker, ranean is written in this paper with a capital M 1981a, 1981b). when the geographical region of the Mediterranean Basin is referred to, but with small case m when Although our studies in the Old World have been vegetation or climate is referred to.) I shall be- carried out in Israel, they reflect a pattern ob- gin this review with a comparison of climates and served in other countries in the Mediterranean floras, then follow with a sequential comparison Basin, especially the eastern part of Greece, of climates and floras, then follow with a sequen- Turkey and Lebanon (personal observations in Tur- tial comparison of major vegetation types found in key, France and Spain). the two areas, including matorral, phrygana, woodland, and montane belts. Differences, as well as similarities, will be emphasized. Although the ENVIRONMENTAL COMPARISON data were taken mainly from Israel, I think that the results are applicable to the whole Mediter- On a gross scale, both areas have a similar ranean Basin. topography: shoreline running north-south, a colline (foothill) belt leading to main ridges running north-south with a steep eastern scarp METHODS facing a desert, and a rift valley. Climatic The conclusions in this paper are based on macro-gradients are also similar: a relatively long, gentle north-south gradient of precipita- 1Presented at the Symposium on Dynamics and tion (falling to the south) and temperature (ris- Management of Mediterranean-type Ecosystems, ing to the south); and east-west orographic gra- June 22-26, 1981, San Diego, California. dients of precipitation, temperature, and contin- entality. In Israel, the gradients are shifted 2Assistant Professor of Botany, The Hebrew toward the warmer, drier portion of the scale, University, Jerusalem, Israel; and Professor, but they occur over smaller distances and, thus, Department of Botany, University of California, can be steeper than gradients in California (Atlas Davis, California. Gen. Tech. Rep. PSW-58. Berkeley, CA: Pacific Southwest Forest and Range 100 Experiment Station, Forest Service, U.S. Department of Agriculture; 1982. of Israel 1970). absolutely dry summers) climate and human disturbance for at least the past 100,000 years. In Differences between the two areas are also California, the mediterranean climate is not so significant: A central valley, with its semi-arid completely bi-phasic and human populations have climate, is absent from Israel; the Sierra Nevada been modest until the last several hundred years ridge is much higher than the Galilee-Judean ridge; (anthropological remains do not extend beyond most of the colline belt of Israel is a low ele- 10,000 yr BP). It is not surprising that Old vation Pleistocene plain with extensive sandy re- World annuals are aggressive when introduced to gions in the south that are open to invasion by western North America, for they are placed in a desert elements, whereas the colline belt of Cali- relatively empty adaptive zone (Robbins 1940, fornia is of older metamorphic hills and mountains Stebbins 1965, Raven and Axelrod 1978). (Avnimelech 1962, Horowitz 1974). Geologically, Israel is mainly underlain by limestone, the weathering of which typically results in stony MATORRAL terra-rosa soil (Zinke 1973). But limestone is rare in California and the soils tend to be less Definition of Terms stony and deeper. Climatically, summer precipitation is completely absent in Israel, whereas In tropical, sub-tropical, and temperate areas, many Californian vegetation types receive at least as annual precipitation falls to 300-600 mm, for- 10 percent of annual precipitation during summer ests give way to either woodland or matorral. If (Baily 1966, Baker 1944, Major 1977). Furthermore, the forest opens up to trees with broad root sys- ,the California coast experiences frequent summer tems and crowns but still with single trunks, fog and the central valley experiences frequent then a woodland results; if canopy cover becomes winter fog, in both cases effectively reducing less than 30 percent, a steppe forest results. evapo-transpiration and the annual amplitude of On the other hand, if the forest becomes shorter temperature (Martoz and Lahey 1975, Major 1977). (2-8 m), but canopy cover remains at 100 percent, Finally, human disturbance has gone on for a long- and the trees are multi-stemmed, a matorral re- er time in Israel, perhaps for 120,000 years sults. If the shrub canopy opens and the ground (Naveh and Dan 1973, Ashman 1973). stratum is invaded by steppic herbs, the result- ing vegetation is a marginal matorral. FLORISTIC COMPARISON The literature of both Israel and California is rich in synonymy for the terms defined above. Although the physiognomies of various herb-, In California, chaparral is the common term for shrub-, or tree-dominated vegetation types are matorral, desert chaparral for marginal matorral, similar in the two mediterranean regions, the and foothill for oak or oak-pine woodland for underlying floras are quite distinct, even at the woodland. Steppe forest would be equivalent to family level. In the shrub-dominated matorral, pinyon-juniper woodland in California. Matorral for example, only one species is shared: Styrax has many synonyms in the Mediterranean region: officinalis. More than 400 taxa which have been garrige or gurique (Quezel 1976, Turril 1930, introduced to California from other, predominantly Taktajan 1941), matorral (Polunin and Smythies mediterranean, areas are now naturalized and wide- 1973), horesh (Zohary 1973), phrygana (Polunin ly distributed in California. But apart from 1980), batha (Fig 1946), and maquis (Zohary 1973). these, the phylogenetic differences in regional I shall use the term maquis to refer to Israeli floras are profound, as even most of the common matorral, reserving phrygana (batha or border genera have had an independent origin" (Raven batha) for a different, soft-leaved lower vege- (1971). Most of the shared evergreen oaks, for tation type. In Israel, the woodland is a example, are not systematically closely related Ceratonia-Pistacia or Quercus woodland, and the (Miller, Tucker, Zohary, and Avishai, personal steppe forest is dominated by Pistacia or Juni- communications). Nevertheless, some pairs of taxa perus. I shall define deserts as regions receiv- which do show relatively close systematic and/or ing less than 150 mm precipitation yearly; semi- ecological relationships in shrub-dominated vege- deserts, including marginal matorral, are

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