Characteristic pattern of species diversity on the Canary Islands

Abstract

Summary:We use an island specific presence/absence data set for the Canary Islands' Arthropoda, Spermatophyta, Fungi, Lichenes, Bryophyta, Mollusca, Chordata, Pteridophyta, Annelida and Nematoda to assess the relative influence of environmental and historical factors on species distribution and endemism. Species richness and the percentage of island endemic species as well as similarity indices for island comparisons were calculated for all species groups. Hierarchical partitioning is used to identify the independent and joined influence of 21 environmental and historical variables. The pattern of species richness is best explained by island elevation. Elevation reflects a variety of factors that contribute to habitat diversity. A similar pattern is detected for the "percentage of single island endemics" (pSIE), a factor associated with speciation. Variables associated with geographical distance have highest explanatory power for biotical similarity of islands. Various Canary Islands species groups show strong distance-decay within the archipelago. According to our findings, speciation is not necessarily driven by species richness or island age alone. Thus, we conclude that correlations between species richness and pSIE, identified in previous studies, could represent an artefact related to differing degrees of isolation between zonal altitudinal ecosystems. This would lead to an increase of speciation with altitude resulting in higher values for pSIE on high altitude islands. Zusammenfassung

Elevational Gradient of Vascular Plant Species Richness and Endemism in Crete – The Effect of Post-Isolation Mountain Uplift on a Continental Island System

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Diversity, Stand Characteristics and Spatial Aggregation of Tree Species in a Bangladesh Forest Ecosystem

“…Distance-decay relations are frequently calculated using log-transformed similarity values, log transformed distance values or both. Most studies dealing with plants use an untransformed relationship [22,47]. Untransformed relations have the advantage of clear interpretation and comparison but bear the problem that: (a) the fitted line has an intercept with the x-axis implying negative similarity values after a certain distance; and (b) that the fitted line has an intercept with the y-axis implying negative distances for specific similarity values.…”

Plant diversity in Oceanic archipelagos: realistic patterns emulated by an agent‐based computer simulation

“…The habitat diversity hypothesis (also the habitat heterogeneity hypothesis, Williams 1964) has been proposed to complement the area per se hypothesis (included in the equilibrium theory of island biogeography, MacArthur and Wilson 1967). It has also been suggested that island elevation might describe the carrying capacity of volcanic islands (Price 2004, Steinbauer andBeierkuhnlein 2010) and hence be a suitable proxy for habitat diversity (Kreft and Jetz 2007). Indeed, adding habitat diversity to the species richness-area model has been shown to improve the descriptive power of models for several archipelagos (e.g.…”

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