A century of decline: Loss of genetic diversity in a southern African lion‐conservation stronghold

Simon G Dures,Chris Carbone,Dada Gottelli,Neil Midlane,Glyn Maude,Andrew J Loveridge,Ortwin Aschenborn,Yolanda Wiersma

doi:10.1111/ddi.12905

Abstract

AbstractAimThere is a dearth of evidence that determines the genetic diversity of populations contained within present‐day protected areas compared with their historical state prior to large‐scale species declines, making inferences about a species’ conservation genetic status difficult to assess. The aim of this paper was to demonstrate the use of historical specimens to assess the change in genetic diversity over a defined spatial area.LocationLike many other species, African lion populations (Panthera leo) are undergoing dramatic contractions in range and declines in numbers, motivating the identification of a number of lion‐conservation strongholds across East and southern Africa. We focus on one such stronghold, the Kavango–Zambezi transfrontier conservation area (KAZA) of Botswana, Namibia, Zambia and Zimbabwe.MethodsWe compare genetic diversity between historical museum specimens, collected during the late 19th and early 20th century, with samples from the modern extant population. We use 16 microsatellite markers and sequence 337 base pairs of the hypervariable control region (HVR1) of the mitochondrial genome. We use bootstrap resampling to allow for comparisons between the historical and modern data.ResultsWe show that the genetic diversity of the modern population was reduced by 12%–17%, with a reduction in allelic diversity of approximately 15%, compared to historical populations, in addition to having lost a number of mitochondrial haplotypes. We also identify a number of “ghost alleles” in the historical samples which are no longer present in the extant population.Main ConclusionsWe argue a rapid decline in allelic richness after 1895 suggests the erosion of genetic diversity coincides with the rise of a European colonial presence and the outbreak of rinderpest in the region. Our results support the need to improved connectivity between protected areas in order to prevent further loss of genetic diversity in the region.

Highlights

Mammal wildlife populations are reported to have undergone a 52% decline in the past half‐century (McRae, Freeman, & Deinet, 2014), but over longer time periods, the ranges and population de‐ clines have been far more severe (Ceballos, 2002; Crees, Carbone, Sommer, Benecke, & Turvey, 2016; Janecka et al, 2014)
The value of genetic diversity is increasingly recognized for con‐ tributing to individual fitness, species’ evolutionary potential, and ecosystem function and resilience (Whitham et al, 2008)
Our analysis demonstrates that over the past century, the lion population of the Kavango–Zambezi region has lost genetic diver‐ sity

Summary

| INTRODUCTION

Mammal wildlife populations are reported to have undergone a 52% decline in the past half‐century (McRae, Freeman, & Deinet, 2014), but over longer time periods, the ranges and population de‐ clines have been far more severe (Ceballos, 2002; Crees, Carbone, Sommer, Benecke, & Turvey, 2016; Janecka et al, 2014) While such studies focus on loses in population sizes and species’ distributions, relatively few have explored temporal losses in genetic diversity (Leonard, 2008), which may have significant impacts on a species’ ability to respond to environmental stochasticity and associated con‐ servation interventions (Spielman, Brook, & Frankham, 2004). Genetic monitoring of indi‐ viduals and populations over time was identified as one of the main topics in need of urgent attention This is especially true for species for which ecological data are unavailable or are overly complex to allow extrapolation from modern genetic data alone, for example, due to uneven mating systems, variation in fecundity among fe‐ males or non‐model dispersal patterns (Björklund, 2003). We used a suite of microsatellite markers as well as sequencing of part of the hypervariable control region (HVR1) of the mitochondrial genome (mtDNA) to assess the degree to which ge‐ netic diversity in this population has been lost as a result of regional declines in lion numbers and distribution

| METHODS

Findings

| DISCUSSION