Fung. Sci. 16(3, 4), 39–46, 2001 Parmelioid lichen biodiversity and distributional ecology in Taiwan Ming-Jou Lai P. O. Box 834, Tunghai University, Taichung, Taiwan 407 (Accepted August 14, 2001) ABSTRACT In total, 19 genera and 97 species are so far known to represent the Taiwanese Parmelia and related genera. In the present study, the correlation of temperature-related habitat preference with the maximum floristic di- versity of parmelioid lichens is analyzed. The coefficient of community (C.C.) is used to compare the floris- tic similarity of parmelioid lichens between the different elevational forest vegetation zones. The boreal or northern temperate elements such as Parmelia, Punctelia, Melanelia, Parmeliopsis, and Imshaugia are common in Tsuga-Picea or Abies forests at higher elevations; whereas Parmotrema, Bulbothrix, Hy- potrachyna, Myelochroa, Parmelinella, Parmelinopsis, Relicina, Rimelia, Canomaculina, and Xantho- parmelia are characteristic of the meridional or pantropical elements which predominate the lowland to montane forests of Quercus, Machilus-Castanopsis, or Ficus-Machilus types. This major distributional differentiation is discussed in terms of the divergent morphogenetic lines based on the cortical struc- tures which differentiate the pseudocyphellate and the epicorticate genera and species (Hale, 1981). Genera having a pored epicortex show the highest biodiversity at submontane-montane elevations (500– 2,500 m), where the forest vegetation is dominated by Machilus-Castanopsis and Quercus (the evergreen broadleaf Lauro-Fagaceae association) communities, and the altitudinal temperature-related climatic zone approximate the meridional (=subtropical-warm orotemperate). Key words: Parmelioid lichens, biodiversity, distributional ecology, Taiwan Introduction chens in Kenya, East Africa (Krog, 1987), the distributional ecology of the Cladoniaceae in In total, 97 species in 19 genera are so far temperate and boreal western North America known to represent the Taiwanese parmelioid (Goward and Ahti, 1997), and the lichen bio- lichens (Kurokawa, 1966; Kurokawa & Lai, diversity in Papua New Guinea (Aptroot, 2001). They form the largest and most impor- 1997). tant portion of the lichen flora of Taiwan. The distribution of lichens is determined primarily Method by temperature and humidity whereas other in- teracting factors such as light conditions and The coefficient of community (C.C.) availability of suitable substrates may be lo- (Sørensen, 1948) is used to compare the floris- cally delimiting (Krog, 1987). Similar case tic similarity of parmelioid lichens between studies have been discussed previously and in- the different elevational forest vegetation clude the elevational zonation of tropical li- zones: 40 Fung. Sci. 16(3, 4), 2001 2a exterior. It is noteworthy that lichens with cc = b + c pseudocyphellae never form a pored epicortex, and consequently lichen species with a pored a: number of common species between two epicortex never form pseudocyphellae. In the communities, humid warm submontane-montane forests of b, c: number of species in each individual Taiwan, parmelioid genera with a pored epi- community. cortex have perforations in the polysaccharide layer exposing the underlying cortical hyphae Forest Vegetation Types and providing passageways to the algal layer (Zones) in Taiwan for gas exchange. By contrast, pseudocyphel- late parmelioid genera and species and the The vegetation of Taiwan exhibits marked cetrarioid lichen groups occur in dry cold vertical zonation which can be summarized in higher elevations (cf. Lai, 2000b). Tempera- terms of climatic factors along an elevational ture and humidity appear to be correlated with gradient as illustrated in Table 1 (Su, 1984). these upper cortical gas exchange structures The elevational vegetation types (zones) are and may play a role as a major distributional recognized by the forest physiognomy as well barrier. as by elevational temperature-related climatic Hale (1981) concluded that pseudocyphellae zones. Some forest vegetation types present in and the pored epicortex in the Parmeliaceae re- the extreme northern or southern parts of the flect two different morphogenetic or phyletic island usually occur at a higher elevation in lines. Genera with a pored epicortex are essen- central Taiwan (cf. Lai, 2000a). tially tropical to subtemperate in distribution, being normally rare or absent in boreal re- Correlation Between Thalline gions, whereas the foliose pseudocyphellate Upper Cortical Structure and genera are very strongly temperate, boreal, or Distributional Ecology even arctic in distribution (see Fig. 1). These two morphological structures represent differ- Among the Taiwanese parmelioid genera, ent mechanisms for achieving gas exchange, the upper cortex of Melanelia, Parmelia, and and in so doing represent biologically isolated Punctelia is perforated by pseudocyphellae lines. which appear as large gaps in the paraplecten- chymatous cortex. The remaining 16 genera Elevational Patterns of (see Table 2, cf. Elix, 1993) have a special Parmelioid Lichens of Taiwan cortical structure, an epicortex, which is a pored polysaccharide sheet overlaying a more The elevational profiles summarized in Ta- or less loosely packed, continuous palisade ble 3 reveal that the majority of the parmelioid parenchymatous layer. The pores can be seen genera and species of Taiwan are distributed only with SEM and range in size from 15 to 40 primarily in submontane-montane elevations µm in diameter (Hale 1973, 1976, 1987). (500–2,500 m) located in the meridional (= These two structures potentially function in warm temperate-subtropical) climatic zone gas exchange between the algal layer and the (Hämet-Ahti et al., 1974). Almost 77 of 97 Parmelioid lichen biodiversity and distribution 41 species and 13 of 19 genera regularly occur Sørensen's (1948) coefficient of community here, as compared with 21 species of 8 genera shows that: C.C. between lowland and sub- at lowland elevations, 27 species of 7 genera at montane elevations equals 35%, between upper montane elevations, 16 species of 5 submontane and montane is 59%, between genera at subalpine elevations, and 3 species montane and upper montane is 45%, between of 1 genus at alpine elevations. upper montane and subalpine is 60%, and be- Floristic similarity of the parmelioid lichen tween subalpine and alpine is 21%. The high species between different elevational forest C.C. value between upper montane and subal- vegetation zones (types) calculated using pine elevations manifests the influence of the Table 1. Temperature ranges of elevational forest vegetation types (zones) in central Taiwan (modified from Su 1984). Tm: annual mean temperature; WI: warmth index. Forest vegetation Equivalent climatic Elevation profile Elevation (m) Tm °C WI °C type zone* Alpine Alpine Krummholz > 3600 < 5 < 12 Oroboreal Subalpine Abies 3100–3600 5–8 12–36 Cold orotemperate Upper montane Tsuga-Picea 2500–3100 8–11 36–72 Cool orotemperate Quercus (upper) 2000–2500 11–14 72–108 Orotemperate Montane Quercus (lower) 1500–2000 14–17 108–144 Warm orotemperate Machilus- Submontane 500–1500 17–23 144–216 Subtropical Castanopsis Lowland Ficus-Machilus < 500 > 23 > 216 Tropical * Climatic zonal nomenclature proposed by Hämet-Ahti et al. (1974). The terms arctic, boreal, meridional (=warm tem- perate-subtropical, 500–2000 m), and tropical also refer to the corresponding thermal zones in the southern hemisphere and in the mountains. Table 2. Upper cortical structure of Taiwanese parmeliod genera Parmelioid genera Pored epicortex Pseudocyphellae Bulbothrix • Canomaculina • Canoparmelia • Certrariastrum • Flavoparmelia • Hypotrachyna • Imshaugia • Karoowia • Melanelia • Myelochroa • Parmelia • Parmelinella • Parmelinopsis • Parmeliopsis • Parmotrema • Punctelia • Relicina • Rimelia • Xanthoparmelia • 42 Fung. Sci. 16(3, 4), 2001 4000 Parmelia 3600 3600 Hypotrachyna Parmelia Imshaugia Parmotrema Melanelia Punctelia 3100 3100 Flavoparmelia Parmotrema Hypotrachyna Punctelia Parmelia Parmeliopsis Rimelia 2500 2500 Certrariastrum Flavoparmelia Hypotrachyna Myelochroa Parmelia Parmelinella Parmelinopsis Parmotrema Punctelia Rimelia 1500 1500 Bulbothrix Canomaculina Canoparmelia Certrariastrum Flavoparmelia Hypotrachyna Myelochroa Parmelinella Parmelinopsis Parmotrema Relicina Rimelia 700 500 Bulbothrix Canomaculina Canoparmelia Karoowia Parmotrema Relicina Rimelia Xanthoparmelia N S Fig. 1. Parmelioid genera in different altitudinal zones. Table 3. Elevation profiles of parmelioid lichens of Taiwan upper mon- Elevation Profile lowland submontane montane subalpine alpine tane cool cold Climate Profile tropical ≒meridional orotemper- orotemper- oroboreal ate ate Bulbothrix goebelii • • Bulbothrix isidiza • • Bulbothrix tabacina • Canomaculina leucosemotheta • Canomaculina subsumpta • Canomaculina subtinctoria • Canoparmelia amazonica • Canoparmelia texana • Cetrariastrum cirrhatum • • • Cetrariastrum nepalense • Cetrariastrum sorocheilum • • • Cetrariastrum subplanum • Cetrariastrum vexans • • Flavoparmelia caperata • • • Hypotrachyna adducta • • Hypotrachyna consimilis • Hypotrachyna crenata • • Hypotrachyna endochlora • • • Parmelioid lichen biodiversity and distribution 43 upper mon- Elevation Profile lowland submontane montane subalpine alpine tane cool cold Climate Profile tropical ≒meridional orotemper- orotemper- oroboreal ate ate Hypotrachyna exsecta • • • Hypotrachyna exsplendens • • Hypotrachyna flexilis • Hypotrachyna imbricatula • Hypotrachyna immaculata