Decoding the Genetic Diversity of Andean Bears: A Path to Conservation

Understanding population genetic diversity is crucial for wildlife conservation. Ecuadorian Andean bear populations currently face significant challenges. To address this, we developed species-specific molecular markers to illuminate the genetic diversity and structure of Andean bears in Ecuador.
Published in Genetics & Genomics
Decoding the Genetic Diversity of Andean Bears: A Path to Conservation

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In wildlife conservation, understanding genetic variation through molecular markers has emerged as an important tool for ecologists and conservation biologists. Over recent decades, advancements in genetic analysis techniques have made these tools more accessible, allowing researchers to study different populations and species in more detail. By looking at genetic information, scientists can learn about how (and if) different wildlife populations are connected, where they came from and how diverse they are — all critical aspects for conservation efforts, particularly for small or isolated groups.

Genetic analysis is particularly important for large carnivores like Andean bears (Tremarctos ornatus). These bears are taxonomically unique and endemic to the Tropical Andes of South America. Living in narrow mountain ranges, they deal with challenges like rough and steep terrain, and conflict associated with human activities. Notably these bears are excellent tree climbers often feeding on flowers and fruits. Hence, bears play a vital ecological role as seed dispersers, and as ecosystem architects as they promote forest renovation through the gaps they create in forest canopy while climbing. Despite their ecological importance, Andean bears face mounting threats, with populations declining throughout their range and in danger of extinction in Ecuador.

Camera trap image of an Andean bear. Photo credits: USFQ Carnivore Lab

Andean bear conservation faces significant challenges in Ecuador, due to the expansion of agricultural frontiers, habitat loss, and the human-bear conflict. Although legal protections exist, the reality reflects potentially small and fragmented Andean bear populations. Understanding the genetic landscape of Andean bears in Ecuador is therefore very important, offering crucial insights into connectivity between populations and guiding targeted conservation efforts toward the most vulnerable areas.

Compared to other bear species, Andean bears remain understudied. Previous studies have relied on a limited set of non-specific genetic markers, that did not succeed in describing in detail the genetic diversity of this species. To address these limitations, we undertook a comprehensive study, developing microsatellite markers specific to this species and analyzing mitochondrial DNA sequences to shed light on the genetic diversity and structure of Andean bear populations in Ecuador.

In a collaborative effort spanning from 2014 to 2020, we aimed to elucidate the genetic diversity of Andean bears throughout the country. We did this by collecting samples from 74 wild bears, including fecal and hair samples. This was done utilizing scent lure methods and camera trap technology to identify individual bears and ensure ethical and non-invasive sampling practices, in compliance with Ecuadorian laws.

One key discovery is the identification of distinct populations of Andean bears in different regions of Ecuador. By analyzing mitochondrial DNA—the genetic material passed down from mothers—we found evidence of genetic differences between bears both in the north-south and east-west axis. Despite geographical proximity (75km), populations in southern Ecuador exhibited significant genetic differentiation, likely influenced by ecological factors, human activities or geographical barriers. The two southern populations displayed lower genetic diversity than their northern counterparts. Our findings suggest that Andean bears in Ecuador are not a single, homogenous population but rather distinct groups with their own genetic characteristics.

Camera trap image of an Andean bear approaching a corral. Photo credits: Fundación Zoológica del Ecuador

Furthermore, our analysis of microsatellite markers—tiny pieces of repetitive DNA that vary between individuals—revealed higher genetic diversity than previous studies performed with non-specific markers across the bear’s range. This is encouraging news for the conservation of Andean bears, as higher genetic diversity means these populations may have a better chance of adapting to environmental changes and surviving in the long term.

Our research highlights the importance of addressing fragmentation and promoting connectivity to ensure the long-term survival of Andean bears. It is also crucial to have tailored conservation strategies that recognize the unique genetic makeup and conservation needs of each population. Maintaining habitat connectivity between different populations of Andean bears means preserving natural corridors that allow bears and co-occurrent wildlife to move between areas without encountering barriers like roads or human settlements. By ensuring these connections, we can help prevent populations from becoming further isolated and at risk of extinction.

Working in the lab to obtain genetic information on Andean bears

Additionally, our findings highlight the importance of using species-specific genetic markers in conservation research. By developing our own set of microsatellite markers designed specifically for Andean bears, we were able to obtain more accurate and reliable results.

The findings from our genetic research have far-reaching implications beyond just Andean bears. They reflect broader conservation challenges in Ecuador and the Andean region overall. The protection of Andean bears and their habitats is not just a matter of preserving a single species; it is about safeguarding the ecological integrity of entire landscapes in the Tropical Andes, a region that many species call home. Not only are these ecosystems worth preserving for their wildlife richness, but they also provide essential services such as freshwater to millions of people.

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