Known from a handful of specimens: analyzing the worldwide patterns of occurrence and conservation of rodents and shrews recorded only from the type locality

Luca Luiselli,Guido Alari Esposito,Giovanni Amori

doi:10.11609/jott.2405.8.3.8556-8563

Luca Luiselli, Guido Alari Esposito

Open Access

https://doi.org/10.11609/jott.2405.8.3.8556-8563

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Abstract

Traditionally, conservation research has not focused on Rodentia and Soricomorpha, and many species are known from a handful of specimens and the type locality only (few and type locality species (FETP)). Here we studied the patterns of occurrence of FETP rodents and soricomorphs in relation to geographical area and vegetation zones and report some conservation considerations. Overall, 91 species of Rodentia and 19 species of Soricomorpha were selected. There was a positive correlation between number of species per genus and number of FETP species in each genus. The majority of FETP rodents occur in the Neotropical, Afrotropical and Oriental regions, and soricomorphs in the Afrotropical and Oriental regions. Higher numbers of FETP rodent species occurred in Argentina and Indonesia. There was a positive relationship between species richness of rodents per country and number of FETP species. In terms of habitat type, FETP species of rodents and soricomorphs showed similar patterns, with most species being found in rainforest. The great majority of selected species of both groups were Data Deficient (DD), with Critically Endangered (CR) accounting for 16.5% of Rodentia and 5.3% of Soricomorpha. Overall, IUCN threatened species mostly occur in the Neotropical region, followed by the Afrotropical region. It is urged that IUCN authorities should promptly revise all FETP species and their precautionary CR status, at least when a reasonable timespan (i.e., >25 years) has passed since the last records.

Highlights

Narrow distribution ranges and small/restricted populations are key elements of extinction risk (e.g., Gaston 1994), with species having restricted distributions and low population sizes being at greatest immediate risk of extinction
The high number of FETP species in Argentina and Indonesia merely depended on a overall high number of rodent species in these countries
Our study showed that a relatively high number of Rodentia (4%) and Soricomorpha (4.4%) species are FETP

Summary

Introduction

Narrow distribution ranges and small/restricted populations are key elements of extinction risk (e.g., Gaston 1994), with species having restricted distributions and low population sizes being at greatest immediate risk of extinction. Some taxa are known only from a handful of individuals and may be functionally analogous to ‘singletons’ in ecological communities (Gaston 1994). As with singletons these species are still largely unknown, and it is open to debate whether face a high risk of extinction or their rarity is a collection artefact. The orders Rodentia and Soricomorpha include about 50% of mammal species, with 2,705 species out of a total of 5,416 (Wilson & Reeder 2005). This study highlights the distribution patterns, main habitats and conservation implications of the rarest/most neglected species of Rodentia and Soricomorpha, known only from their type locality and less than 10 individuals (hereby FETP species)

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