A phylogeographic framework for the conservation of Saharan and Arabian Dorcas gazelles (Artiodactyla: Bovidae)

Abstract

Many species of gazelles (Gazella spp.) are nowadays threatened by hunting, poaching, habitat loss and habitat deterioration. Conservation efforts for this group not only face the problem of maintaining remnant populations, but often natural populations have been extirpated from the wild. In some cases, though, captive breeding programs exist that might provide a valuable source for future reintroductions. A major problem in this context is that phylogeographic relationships among different (potentially locally adapted) populations, and even basic phylogenetic relationships between species, are poorly understood, thus hampering the assignment of management units, breeding groups or stocks for reintroduction projects. Our present study focused on Dorcas gazelles (G. dorcas and G. saudiya) from the species' entire distribution range, with samples originating from western Saharan Africa into Saudi Arabia. In stark contrast to previous studies reporting on pronounced genetic structure in taxa such as Mountain gazelles (G. gazella), we detected low genetic diversity and no evidence for major phylogenetic lineages when analyzing two mitochondrial genetic markers. Using a coalescent approach we infer a steep population decline that started approximately 25,000 years before present and is still ongoing, which coincides with human activities in Saharan Africa. Our phylogenetic analyses, statistical parsimony network analysis and inferred colonization patterns shed doubt on the validity of various described subspecies of G. dorcas.

Conservation genetics of the endangered Dorcas gazelle (Gazella dorcas spp.) in Northwestern Africa

“…While the mtDNA control region is certainly more variable than cyt b in mammals, we chose this gene because it has been frequently used in the study of Gazella species (e.g. Hammond et al 2001;Lerp et al 2011;Wacher et al 2010), thus allowing more direct comparisons between different datasets. Reaction mixtures included 0.1 units of GoTaq (Promega), 3 mM MgCl2, 0.5 lM of each primer, 4 lM of each dNTP and approximately 10 ng of genomic DNA (or 1 ll of DNA extraction for non-invasive samples) in a total volume of 10 ll.…”

“…To investigate phylogenetic and geographic relationships among the different mitochondrial haplotypes we applied the median-joining algorithm for reconstruction of all possible evolutionary pathways among the haplotypes (Bandelt et al 1999) using the software Network 4.5 (Röhl 2000). In addition, we downloaded a set of 52 cyt b sequences which were recently published by Lerp et al (2011) for G. dorcas covering most of the distribution range of the species (including Mali, Algeria, Tunisia, Chad, Sudan, Egypt and Israel). These sequences were trimmed to the 716 bp size applied in this study and then used to estimate genetic diversity parameters and reconstruct a global median-joining network.…”

“…The analysis of the partial cyt b sequences published by Lerp et al (2011) provided a number of useful insights on the evolutionary history of G. dorcas and additionally helped to put in perspective our own results. First, samples grouped by Lerp et al in West and South Central regions of North Africa exhibited levels of haplotype diversity (H d = 0.857 and H d = 0.782, respectively) and nucleotide diversity (p = 0.004 and p = 0.002, respectively) that were found to be well within those reported for the populations of FE ''la Hoya'' and Safia (Table 2).…”

“…Partly, this controversy is because taxonomic classification was based exclusively on morphological characteristics (e.g. colour, size, or shape of horns) but, to our knowledge, no studies until now have attempted a comprehensive molecular systematic approach (but see Lerp et al 2011 for a recent phylogeographic approach). In the northwestern corner of Africa, the situation is particularly confusing and at least five different subspecific names have been used (Panouse 1957;Gentry 1971;Groves 1969Groves , 1981Alados 1987).…”

<b>The status of Arabian Gazelles <I>Gazella arabica</I> (Mammalia: Cetartiodactyla: Bovidae) in Al Wusta Wildlife Reserve and Ras Ash Shajar Nature Reserve, Oman</b>

“…Previously known as the Mountain Gazelle Gazella gazella, the species was recently split into two genetically distinct lineages (G. arabica and G. gazella; Lerp et al 2013). Arabian Gazelle populations have been in decline for many years.…”