In the depths of obscurity: Knowledge gaps and extinction risk of Brazilian worm lizards (Squamata, Amphisbaenidae)

Colli, Guarino R.; Fenker, Jéssica; Tedeschi, Leonardo G.; Barreto‐Lima, André Felipe; Mott, Tamí; Ribeiro, Síria

doi:10.1016/j.biocon.2016.07.033

Cited by 42 publications

(36 citation statements)

References 56 publications

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“…Generally, scientists observed, distinguished and described the widely distributed species early. In fact, range size consistently emerges as the key correlate of description date in all tests we know that examined this link (e.g., Collen, Purvis, & Gittleman, 2004;Colli et al, 2016;Costello et al, 2015;Diniz-Filho et al, 2005). Species that were discovered and described (as opposed to being split from other species) relatively recently are poorly known almost by definition, given that not enough time has lapsed for biologists to study their biology, abundance and true range extent.…”

Section: Introductionmentioning

confidence: 99%

Extinct, obscure or imaginary: The lizard species with the smallest ranges

Meiri

Bauer

Allison

et al. 2017

Diversity and Distributions

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Aim Small geographic ranges make species especially prone to extinction from anthropogenic disturbances or natural stochastic events. We assemble and analyse a comprehensive dataset of all the world's lizard species and identify the species with the smallest ranges—those known only from their type localities. We compare them to wide‐ranging species to infer whether specific geographic regions or biological traits predispose species to have small ranges. Location Global. Methods We extensively surveyed museum collections, the primary literature and our own field records to identify all the species of lizards with a maximum linear geographic extent of <10 km. We compared their biogeography, key biological traits and threat status to those of all other lizards. Results One in seven lizards (927 of the 6,568 currently recognized species) are known only from their type localities. These include 213 species known only from a single specimen. Compared to more wide‐ranging taxa, they mostly inhabit relatively inaccessible regions at lower, mostly tropical, latitudes. Surprisingly, we found that burrowing lifestyle is a relatively unimportant driver of small range size. Geckos are especially prone to having tiny ranges, and skinks dominate lists of such species not seen for over 50 years, as well as of species known only from their holotype. Two‐thirds of these species have no IUCN assessments, and at least 20 are extinct. Main conclusions Fourteen per cent of lizard diversity is restricted to a single location, often in inaccessible regions. These species are elusive, usually poorly known and little studied. Many face severe extinction risk, but current knowledge is inadequate to properly assess this for all of them. We recommend that such species become the focus of taxonomic, ecological and survey efforts.

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Section: Introductionmentioning

confidence: 99%

Extinct, obscure or imaginary: The lizard species with the smallest ranges

Meiri

Bauer

Allison

et al. 2017

Diversity and Distributions

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“…Declines have occurred at global 23 and regional levels 24 , and there is growing concern over potential widespread snake declines 25 , 26 with a poor understanding of the underlying causes 8 , 23 , 26 , 27 . Bridging the gap in reptile threat assessment is challenging, with evolutionary and biological traits influencing both extinction risk and our ability to gather appropriate information 28 , 29 . Attempts to monitor these populations are often carried out by regional or national organisations, such as those in the UK 30 and the Netherlands 22 .…”

Section: Introductionmentioning

confidence: 99%

“…Snakes have some of the lowest detection rates among reptiles 16 (perhaps with the exception of fossorial taxa such as Amphisbaenia 19 , 29 ). They can occur at low densities, have wide ranges, cryptic colouration and behaviour, and are often unobservable due to their chosen habitats 16 .…”

Section: Introductionmentioning

confidence: 99%

Optimising monitoring efforts for secretive snakes: a comparison of occupancy and N-mixture models for assessment of population status

Ward

Griffiths

Wilkinson³

et al. 2017

Sci Rep

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A fifth of reptiles are Data Deficient; many due to unknown population status. Monitoring snake populations can be demanding due to crypsis and low population densities, with insufficient recaptures for abundance estimation via Capture-Mark-Recapture. Alternatively, binomial N-mixture models enable abundance estimation from count data without individual identification, but have rarely been successfully applied to snake populations. We evaluated the suitability of occupancy and N-mixture methods for monitoring an insular population of grass snakes (Natrix helvetica) and considered covariates influencing detection, occupancy and abundance within remaining habitat. Snakes were elusive, with detectability increasing with survey effort (mean: 0.33 ± 0.06 s.e.m.). The probability of a transect being occupied was moderate (mean per kilometre: 0.44 ± 0.19 s.e.m.) and increased with transect length. Abundance estimates indicate a small threatened population associated to our transects (mean: 39, 95% CI: 20–169). Power analysis indicated that the survey effort required to detect occupancy declines would be prohibitive. Occupancy models fitted well, whereas N-mixture models showed poor fit, provided little extra information over occupancy models and were at greater risk of closure violation. Therefore we suggest occupancy models are more appropriate for monitoring snakes and other elusive species, but that population trends may go undetected.

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“…The Cerrado exhibits intricate biogeographic patterns, shaped by local environments and regional constraints, such as proximity to, or isolation from, neighboring domains and areas with contiguous relief (Werneck 2011). Its biodiversity remains poorly understood and every year many new species are described, indicating that significant biodiversity remains to be discovered (Colli et al 2016;Diniz et al 2010;Diniz-Filho et al 2005). The Cerrado is the most diverse tropical savanna in the world and, except for a few tropical forest regions, has the richest vascular plant flora on the planet (Eiten 1994).…”

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confidence: 99%

Biodiversity and conservation of the Cerrado: recent advances and old challenges

2020

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Background Covering about 2 Mio. km 2 by the arrival of the first European settlers, the Cerrado savannas are second in extent only to Amazonian forests amongst the South American biomes (Diniz et al. 2010; Eiten 1972; Oliveira and Marquis 2002). The Cerrado sits strategically at the centre of the continent, connecting two open vegetation biomes-the Chaco to the southwest and the Caatinga to the northeast-thus forming a diagonal corridor of dry habitats in South America, and simultaneously establishing a biogeographical barrier between two forest biomes-Amazonia to the northwest and the Atlantic Forest to the southeast (Schmidt and Inger 1951; Vanzolini 1963; Werneck 2011). Moreover, it also occurs as isolated patches within other biomes, presumably relicts of a more extensive past distribution (

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In the depths of obscurity: Knowledge gaps and extinction risk of Brazilian worm lizards (Squamata, Amphisbaenidae)

Cited by 42 publications

References 56 publications

Extinct, obscure or imaginary: The lizard species with the smallest ranges

Extinct, obscure or imaginary: The lizard species with the smallest ranges

Optimising monitoring efforts for secretive snakes: a comparison of occupancy and N-mixture models for assessment of population status

Biodiversity and conservation of the Cerrado: recent advances and old challenges

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