Geographical patterns and environmental drivers of functional diversity and trait space of amphibians of Europe

Abstract

Amphibians are among the most endangered group of vertebrates. To conserve their diversity we need to comprehend how functional diversity and species traits vary across environmental gradients. We investigate the distribution of functional diversity (functional richness-functional dispersion-functional evenness) and the environmental drivers (climate, energy availability, landscape and anthropogenic attributes) of these patterns for the 68 amphibian species of Europe using generalized least squares models and hierarchical partitioning. Based on eight functional traits, species were arranged in a multidimensional functional trait space and principal coordinates analysis (PCoA) was applied to investigate the occupancy of this space by amphibians. Functional richness mirrored species richness pattern and decreased towards higher latitudes; while, functional dispersion showed an even stronger negative correlation with latitude. Functional evenness did not display a clear latitudinal trend.Areas with higher functional richness and functional dispersion are associated with lower temperature seasonality and increased land cover diversity, in contrast areas with higher functional evenness are characterized by lower mean annual temperature.Climate seasonality mostly influenced the traits related to the first two PCoA axes (i. e., foraging location, mobility mode) which could have been considered as functional response traits and could be used as indicators to examine how communities respond to environmental change. Our work describes the macroecological patterns and discusses the relative importance of alternative underlying mechanisms driving functional diversity of this high-risk taxonomical group and highlight that species richness presents only part of the biodiversity patterns, while other facets like functional evenness behave distinctively differently. K E Y W O R D Samphibians, climate, functional diversity, functional trait space, seasonality

Evolutionary history drives aspects of stoichiometric niche variation and functional effects within a guild

“…5D). Previous work has found that functional dispersion increases with species richness (Tsianou and Kallimanis 2020) often increasing to a threshold (Laliberté and Legendre 2010, Lamothe et al 2018). Our results may be partially attributable to working within a single river system with our communities being relatively similar as a result of a restricted regional species pool.…”

The effect of climate and human pressures on functional diversity and species richness patterns of amphibians, reptiles and mammals in Europe<sup>†</sup>

“…On the other hand, previous research indicate that mammal functional diversity accommodates higher species "packing" in areas with higher temperature leading to higher similarity of traits between species and thus decrease of functional diversity [14]. Precipitation reflecting water availability affects reproduction of ectotherm species, and its significance has been previously demonstrated for ectotherm richness [36] and functional diversity [22]. Here, reptile functional diversity increased with precipitation, while a unimodal relationship was observed in the case of amphibians and mammals.…”

“…Here, reptile functional diversity increased with precipitation, while a unimodal relationship was observed in the case of amphibians and mammals. There has been a lot of discussion about the key effect of seasonality on functional diversity patterns [10,11,14,22]. Seasonality performed either as a driver or filter for functional traits of amphibians, reptiles and mammals of Europe.…”

“…We compiled trait datasets for amphibians, reptiles and mammals of Europe using a number of available databases (published papers, books, electronic databases given upon request). The selection of traits was based on the completeness of the availability of species' trait data and on their previous use of them in quantifying amphibian, reptile and mammal functional diversity [14,22]. Our trait selection process resulted in the following nine functional traits: (a) body length (body mass for mammals), (b) clutch size (litter size for mammals), (c) age at sexual maturity, (d) reproductive period (only for amphibians and reptiles), (e) oviposition site (only for amphibians and reptiles), (f) activity time, (g) diet type, (h) foraging location and (i) mobility mode (only for amphibians and reptiles) (a-c traits were considered as numerical variables and d-i traits as binary variables).…”

“…Recent studies report that urbanization has substantial negative impacts on functional diversity and that highly urbanized communities show significant decreased functional diversity in contrast with the natural environments [20,21]. But still, understanding the contribution of human pressures on large scale patterns of functional diversity and their relative importance compared to other mechanisms such as climate remains fragmentary [16,18,22]. Furthermore, functional diversity patterns have generally been investigated to single taxonomic groups, despite the fact that different taxa may play similar and/or complementary ecological and functional roles [16,23].…”