The impact of conservation on the status of the world's vertebrates

Using data for 25,780 species categorized on the International Union for Conservation of Nature Red List, we present an assessment of the status of the world's vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: On average, 52 species of mammals, birds, and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth again as much in the absence of these. Nonetheless, current conservation efforts remain insufficient to offset the main drivers of biodiversity loss in these groups: agricultural expansion, logging, overexploitation, and invasive alien species.

High level of cryptic species diversity revealed by sympatric lineages of Southeast Asian forest frogs

Amphibians tend to exhibit conservative morphological evolution, and the application of molecular and bioacoustic tools in systematic studies have been effective at revealing morphologically 'cryptic' species within taxa that were previously considered to be a single species. We report molecular genetic findings on two forest-dwelling ranid frogs from localities across Southeast Asia, and show that sympatric evolutionary lineages of morphologically cryptic frogs are a common pattern. These findings imply that species diversity of Southeast Asian frogs remains significantly underestimated, and taken in concert with other molecular investigations, suggest there may not be any geographically widespread, forest-dwelling frog species in the region. Accurate assessments of diversity and distributions are needed to mitigate extinctions of evolutionary lineages in these threatened vertebrates.

Molecular systematics and biogeography of the fanged frogs of Southeast Asia

Our analysis of parts of the mitochondrial ribosomal 12S and 16S genes from 39 populations of Southeast Asian ranid frogs confirms that the fanged frogs are a monophyletic clade. This group, properly called Limnonectes, appears to have arisen in the early Tertiary at a time when free faunal exchange was possible among Southeast Asia, Borneo, Sumatra, Java, and, probably, Sulawesi. Four species groups are tentatively identified within the clade. Part of group 1 includes species related to L. kuhlii that occur in Borneo. Another part of group 1 includes species from Malay Peninsula and Thailand that are related to L. pileata. Species group 2, L. leporina, occurs only in Borneo. Species group 3 is restricted to species distributed in Sulawesi and the Philippines. Species group 4 includes L. blythii and relatives. There is a lack of compatibility between phylogenetic hypotheses generated from molecular and morphological data sets. These differences are related, in large part, to whether some species of Limnonectes have secondarily lost fangs or whether lack of fangs represents the primitive condition.

Morphological variation and ecological distribution of co-occurring larval forms of Oreolalax (Anura: Pelobatidae)

Abstract

The amphibian fauna of Sichuan Province, China, is remarkable for the large number of species of pelobatid frogs, of which species of Oreolalax form a large portion. We have collected larvae of five species of Oreolalax on Mt. Emei, Sichuan, four of these five at a second locality 40 km from Mt. Emei, and larvae of two additional species at a locality 200 km S of Mt. Emei. These tadpoles are very similar to one another morphologically, a conclusion supported by multivariate analysis. We give diagnostic descriptions and a key for the identification of these seven larval forms. All tadpoles of Oreolalax have lotic habits, and the seven species in our study live in small to medium-sized streams (maximum width 8 m). These species show only moderate ecological segregation in terms of stream size and microhabitat type.

Ecological structure of a herpetological assemblage in South India

Abstract

We collected detailed microhabitat information on 1460 specimens comprising 52 species of amphibians and reptiles from a small area of tropical evergreen forest in South India. Although most individuals were found in non-riparian situations, the number caught in and along streams was higher than expected on the basis of collecting effort. Very few animals were caught under logs and rocks. When niche breadth values are corrected for variation in sample size, we find no correlation between magnitude of niche breadth and general habitat usage, such as terrestriality vs. arboreality. A cluster analysis of 28 common species using niche overlap values reveals one group of 6 terrestrial species with very high niche overlap values and high co-occurrence within collecting sorties; this group probably represents a genuine terrestrial guild. Another set of 4 terrestrial species is peripherally associated with the first 6, whereas the remaining species show generally low overlap values. Altitudinal restriction is an almost ubiquitous feature of the distribution of species in this fauna, with distinct groups of low (below 300 m), intermediate (300-399 m), and high altitude (above 399 m) taxa roughly corresponding to major shifts in forest types. At a broader level of analysis, we find considerable evidence for local endemism within partially isolated hill ranges in the Western Ghats, suggesting that geographic isolation may be an important contributing factor to the diversity of the South Indian herpetofauna.