Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.

<h4>Background</h4>Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20(th) century, increased aridity combined with human persecution led to local extinction. Knowledge on distribut...

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Autores principales:	José C Brito, Fernando Martínez-Freiría, Pablo Sierra, Neftalí Sillero, Pedro Tarroso
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2011
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/81c7207e123c4b378671d797adc2f3a2
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spelling	oai:doaj.org-article:81c7207e123c4b378671d797adc2f3a22021-11-18T06:58:11ZCrocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.1932-620310.1371/journal.pone.0014734https://doaj.org/article/81c7207e123c4b378671d797adc2f3a22011-02-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21364897/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20(th) century, increased aridity combined with human persecution led to local extinction. Knowledge on distribution, occupied habitats, population size and prey availability is scarce in most populations. This study evaluates the status of Saharan crocodiles and provides new data for Mauritania to assist conservation planning.<h4>Methodology/principal findings</h4>A series of surveys in Mauritania detected crocodile presence in 78 localities dispersed across 10 river basins and most tended to be isolated within river basins. Permanent gueltas and seasonal tâmoûrts were the most common occupied habitats. Crocodile encounters ranged from one to more than 20 individuals, but in most localities less than five crocodiles were observed. Larger numbers were observed after the rainy season and during night sampling. Crocodiles were found dead in between water points along dry river-beds suggesting the occurrence of dispersal.<h4>Conclusion/significance</h4>Research priorities in Chad and Egypt should focus on quantifying population size and pressures exerted on habitats. The present study increased in by 35% the number of known crocodile localities in Mauritania. Gueltas are crucial for the persistence of mountain populations. Oscillations in water availability throughout the year and the small dimensions of gueltas affect biological traits, including activity and body size. Studies are needed to understand adaptation traits of desert populations. Molecular analyses are needed to quantify genetic variability, population sub-structuring and effective population size, and detect the occurrence of gene flow. Monitoring is needed to detect demographical and genetical trends in completely isolated populations. Crocodiles are apparently vulnerable during dispersal events. Awareness campaigns focusing on the vulnerability and relict value of crocodiles should be implemented. Classification of Mauritanian mountains as protected areas should be prioritised.José C BritoFernando Martínez-FreiríaPablo SierraNeftalí SilleroPedro TarrosoPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 6, Iss 2, p e14734 (2011)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q José C Brito Fernando Martínez-Freiría Pablo Sierra Neftalí Sillero Pedro Tarroso Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
description	<h4>Background</h4>Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20(th) century, increased aridity combined with human persecution led to local extinction. Knowledge on distribution, occupied habitats, population size and prey availability is scarce in most populations. This study evaluates the status of Saharan crocodiles and provides new data for Mauritania to assist conservation planning.<h4>Methodology/principal findings</h4>A series of surveys in Mauritania detected crocodile presence in 78 localities dispersed across 10 river basins and most tended to be isolated within river basins. Permanent gueltas and seasonal tâmoûrts were the most common occupied habitats. Crocodile encounters ranged from one to more than 20 individuals, but in most localities less than five crocodiles were observed. Larger numbers were observed after the rainy season and during night sampling. Crocodiles were found dead in between water points along dry river-beds suggesting the occurrence of dispersal.<h4>Conclusion/significance</h4>Research priorities in Chad and Egypt should focus on quantifying population size and pressures exerted on habitats. The present study increased in by 35% the number of known crocodile localities in Mauritania. Gueltas are crucial for the persistence of mountain populations. Oscillations in water availability throughout the year and the small dimensions of gueltas affect biological traits, including activity and body size. Studies are needed to understand adaptation traits of desert populations. Molecular analyses are needed to quantify genetic variability, population sub-structuring and effective population size, and detect the occurrence of gene flow. Monitoring is needed to detect demographical and genetical trends in completely isolated populations. Crocodiles are apparently vulnerable during dispersal events. Awareness campaigns focusing on the vulnerability and relict value of crocodiles should be implemented. Classification of Mauritanian mountains as protected areas should be prioritised.
format	article
author	José C Brito Fernando Martínez-Freiría Pablo Sierra Neftalí Sillero Pedro Tarroso
author_facet	José C Brito Fernando Martínez-Freiría Pablo Sierra Neftalí Sillero Pedro Tarroso
author_sort	José C Brito
title	Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
title_short	Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
title_full	Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
title_fullStr	Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
title_full_unstemmed	Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.
title_sort	crocodiles in the sahara desert: an update of distribution, habitats and population status for conservation planning in mauritania.
publisher	Public Library of Science (PLoS)
publishDate	2011
url	https://doaj.org/article/81c7207e123c4b378671d797adc2f3a2
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Crocodiles in the Sahara desert: an update of distribution, habitats and population status for conservation planning in Mauritania.

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