A new study led by EBD-CSIC points to the need for a rapid increase and redistribution of the populations on the peninsula to guarantee their survival.
The researchers have detected that with the disappearance of the wolf in Sierra Morena, a unique DNA sequence typical of the population that inhabited this area has been lost.
Researchers from EBD are leading an international study that has found that the Iberian wolf population, despite its apparent recovery, has lost genetic diversity, which poses a risk to its survival. The research group, in collaboration with the University of Potsdam (Germany), has analysed the complete mitochondrial genome of specimens of historical wolves conserved in the scientific collections of the EBD (ICTS-RBD). The study, published in the journal Genes, indicates that a rapid population increase, including all possible subpopulations, could protect Iberian wolves from further loss of genetic diversity.
The wolf population in the Iberian Peninsula has declined in size and distribution over the last 200 years due to human persecution and habitat fragmentation, reaching a historic population low around 1970. Since then, the population has initially increased in numbers, stabilising over the last 30 years, and now occupies the northwest of the peninsula. However, this stability hides a loss of diversity.
EBD Researchers have studied the genetic variability of Iberian wolves over the last 50 years, and have found mitochondrial haplotypes that do not appear outside the Peninsula, showing a unique genetic legacy in Iberian wolves. A mitochondrial haplotype consists of a unique sequence of mitochondrial DNA, the biomolecule found in the mitochondria of cells that constitutes the genetic material inherited through the maternal line in eukaryotic living beings.
The missing DNA in Sierra Morena
Comparison of the complete mitochondrial DNA of present-day wolves with that of several decades ago has revealed that one of these haplotypes was only found in wolves from the south of the distribution, in Sierra Morena. "There is very little population genetic data in Sierra Morena. In this study, we found that the historical wolves in this region shared the same haplotype as one of the last wolves living in Sierra Morena for which genetic data are available, a wolf found run over in 2003. However, none of the wolves analysed from the current population in the northwest of the peninsula had this haplotype," explains Isabel Salado, researcher at EBD-CSIC. "This haplotype has probably disappeared along with the extinction of the Sierra Morena population," adds Jennifer A. Leonard, researcher at EBD-CSIC.
"Local extinctions in a fragmented population can facilitate the loss of diversity, even if the total population size is apparently stable," says Carles Vilà, researcher at EBD-CSIC. According to the Convention on Biological Diversity, genetic variability is considered one of the forms of biodiversity that should be conserved, along with the diversity of species and ecosystems, because it favours the long-term viability of the population.
This study shows the relevance of historical specimens in applied conservation research and highlights the need for genetic monitoring of wild populations over time, especially those that have suffered drastic population declines in recent centuries. "The genetic study of the population in the past and present allows us to detect conservation problems, such as the loss of genetic variability," says Salado.
This study is part of the knowledge generation project "Frontera" of the Junta de Andalucía (P18-FR-5099), and is also funded by two pre-doctoral contracts by the Ministry of Universities (FPU17/02584) and the Ministry of Economic Affairs and Digital Transformation (BES-2017-082260).
Comunicación Estación Biológica de Doñanaoutreach@ebd.csic.es https://www.mdpi.com/2073-4425/14/1/75