Date Published: January 26, 2017
Publisher: Public Library of Science
Author(s): Daniel Escoriza, Jihène Ben Hassine, Benedikt R. Schmidt.
The composition and diversity of biotic assemblages is regulated by a complex interplay of environmental features. We investigated the influence of climate and the aquatic habitat conditions on the larval traits and the structure of amphibian larval guilds in north-western Africa. We classified the species into morphological groups, based on external traits: body shape, size, and the relative positions of the eyes and oral apparatus. We characterized the guild diversity based on species richness and interspecific phylogenetic/functional relationships. The larvae of the urodeles were classified as typical of either the stream or pond type, and the anurans as typical of either the lentic-benthic or lentic-nektonic type. The variations in the body shapes of both urodeles and anurans were associated with the type of aquatic habitat (lentic vs lotic) and the types of predators present. Most of the urodele guilds (98.9%) contained a single species, whereas the anuran guilds were usually more diverse. Both the phylogenetic and functional diversity of the anuran guilds were positively influenced by the size of the aquatic habitat and negatively by aridity. In anurans, the benthic and nektonic morphological types frequently co-occurred, possibly influenced by their opportunistic breeding strategies.
The factors regulating the variation of biotic communities along ecological gradients have been much studied in ecology because of their implications in understanding the processes underlying species associations [1,2]. Community diversity is determined by a complex interplay of habitat features, species interactions and present/historical climatic conditions [3,4]. This means that the variation in community diversity is not always simply correlated with environmental predictors, particularly over relatively large spatial scales .
We detected the presence of amphibian larvae in a large part of the study area (Fig 1). In most of the water bodies surveyed urodele guilds included only a single species (98.9%), whereas in anurans 53.6% of water bodies comprised one species, 38.9% two species, 6.1% three species, and 1.4% four species. The characteristics of the water bodies and sites where each species occurred (Tables 1 and 2) showed that some species tolerate a wide variety of environmental parameters, particularly some bufonids and ranids such Amietophrynus mauritanicus, Bufotes boulengeri and Pelophylax saharicus.
Compared with other Mediterranean regions, only a small number of amphibian species inhabit north-west Africa [70,71]. Here we present the first comprehensive assessment of the factors determining the phylogenetic and functional diversity of the amphibian guilds in north-western Africa.