Genetic Diversity of Caribou: Insights for Conservation and Herd Survival

Jenn Hoskins
14th May, 2024

Genetic Diversity of Caribou: Insights for Conservation and Herd Survival

Image Source: Ryan Noeker (photographer)

Key Findings

  • The study analyzed genetic relationships among nine caribou herds at the Alaska-Yukon border
  • The Fortymile herd was the only one assigned to multiple genetic clusters, indicating its historical role in maintaining genetic diversity
  • Some herds, like Chisana and Klaza, were genetically distinct, while others, like Hart River and Clear Creek, showed little differentiation despite occasional overlap
Caribou populations in North America are facing significant threats due to habitat fragmentation and loss. These pressures have led to the need for better conservation strategies, particularly for endangered herds like the Fortymile caribou. A recent study conducted by Southern Oregon University[1] provides the first fine-scale analysis of genetic population structure among nine contiguous caribou herds at the boundaries between Barren-ground and Northern Mountain caribou, as well as at the Alaska-Yukon border. This research aims to inform conservation decision-making by enhancing our understanding of genetic relationships between these herds. The study analyzed 15 microsatellite loci in 379 caribou using pairwise differentiation metrics, STRUCTURE, and discriminant analysis of principal components (DAPC). The results revealed complex patterns of genetic differentiation among the herds. Notably, the Fortymile herd was the only one assigned to more than one genetic cluster. This finding suggests that the Fortymile herd, historically larger, played a crucial role in maintaining genetic diversity across a functioning genetic metapopulation through range expansions and gene flow to other herds. Previous research has shown that wide-ranging animals, including caribou, are significantly threatened by habitat fragmentation and loss[2]. In the case of caribou, genetic studies have indicated a subdivision into Northern and Southern genetic clusters, with specific single nucleotide polymorphisms (SNPs) associated with migratory behavior[2]. The current study builds on this understanding by highlighting the importance of genetic connectivity among herds, even in the absence of demographic connectivity. Some herds, such as Chisana, Klaza, and White Mountains, were found to be genetically distinct, while others, like Hart River, Clear Creek, and Mentasta, exhibited little differentiation despite occasional overlap. The findings align with earlier studies that emphasized the need to address genetic connectivity in fragmented populations[3]. For instance, gene flow in caribou was shown to be restricted to neighboring local populations, with landscape resistance, geographic distances, and predation risk correlated with genetic distances[3]. The current study's observation that some herds maintain genetic differentiation despite episodic contact during rut further underscores the complexity of caribou population dynamics. Moreover, the research highlights the limitations of genetic clustering algorithms, such as STRUCTURE, which require sufficient data to produce informative results[4]. The study's use of multiple analytical methods, including DAPC, allowed for a more nuanced understanding of genetic relationships. This approach is crucial for accurately identifying genetic clusters and informing conservation strategies. The study's findings have significant implications for caribou conservation. Managing caribou for an appropriate level of genetic connectivity, while also supporting herd persistence, will be essential to conserve genetic diversity in the region. This approach aligns with recommendations from previous reviews, which suggested that many studies may have over- or underestimated population genetic structure due to methodological limitations[5]. In conclusion, the research conducted by Southern Oregon University provides valuable insights into the genetic relationships between caribou herds at the Alaska-Yukon border. By revealing complex patterns of genetic differentiation and emphasizing the importance of genetic connectivity, this study contributes to the development of more effective conservation strategies for endangered caribou populations.

GeneticsEcologyAnimal Science

References

Main Study

1) Population genetics of caribou in the Alaska-Yukon border region: implications for designation of conservation units and small herd persistence

Published 13th May, 2024

https://doi.org/10.1007/s10592-024-01612-y

Related Studies

2) Genomic legacy of migration in endangered caribou.

https://doi.org/10.1371/journal.pgen.1009974

3) Environmental and anthropogenic drivers of connectivity patterns: A basis for prioritizing conservation efforts for threatened populations.

https://doi.org/10.1111/eva.12443

4) Inferring weak population structure with the assistance of sample group information.

https://doi.org/10.1111/j.1755-0998.2009.02591.x

5) The K = 2 conundrum.

https://doi.org/10.1111/mec.14187


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