Habitat Connectivity Proven Key Through Genetic Profile Analysis to Conservation of African Forest Elephants

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Photo of a male forest elephant at the Langoué Bai, Ivindo National Park, Gabon.

 

The drastic decline in both the Central African forest elephant’s population and habitat range over the past decade has increased the species’ conservation value and prompted researchers to find effective conservation strategies for the elephants.  Multiple use areas (MUAs) create habitat corridors between Protected Areas in Gabon that aid in gene flow and provide additional habitat for the elephants.

Human impact has been proven to be one of the strongest factors influencing forest elephant population distribution. Logging, roads, and poaching have all contributed to the population decline of the elephants and habitat fragmentation observed in Gabon.

Approximately half of the entire African forest elephant population resides in Gabon and the MUA evaluated in this study is estimated to be home to 10% of all African forest elephants.

Poaching became so severe in Gabon in recent years that law now protects elephants and an antipoaching military unit has been established.

In order to emphasize the importance of multiple use areas between national parks and protected areas, researchers analyzed data focused on genetic variability, geographic movement, age, and sex of the African forest elephants.

Dung samples were collected from six MUA sites and 5 sites in national parks surrounding the MUA. Dung samples were more commonly found and collected near water sites.

The age of individuals in the samples was based off of dung circumference, which could have lead to incorrect categorization for some young females.

DNA was isolated from the dung, amplified at specific genetic markers, run through quality checks, and analyzed using several programs.

DNA isolated from the samples was analyzed at several loci, including mitochondrial DNA for over 500 individuals.

Genetic analysis showed that females were much more prevalent in the MUAs. Male elephants were more likely to be found in open areas in the dry season although the female to male ratio was 5:1.

 Analysis also suggests that movements during the wet season (compared to the dry season) and long-range movements were much more rare than their counterparts.

Data from the DNA analysis suggest that some elephants reside in the MUA year-round, while some elephants merely migrate to water sources in the MUAs during the dry season.

Based on the data, elephants found in the MUAs are from several groups rather than random individuals, although genetic variation was greatest in the parks surrounding the MUA.

Parks with biotic or abiotic barriers to the MUA tend to have resident populations that rarely make movements into the MUA.  Supporting this, Iguela had the most genetically distinct samples, probably because of the lagoon isolating the park from the MUA.

Despite barriers, MUAs provide sites for genetically diverse elephants to congregate and also provides additional resources for the populations.

With the recent increase in deforestation due to logging and road construction, access to MUAs will limit the forest elephants’ access to water sites, extra resources, and will limit gene flow among the population.

It is possible that with increased resource consumption in the area, especially logging, that protection of this MUA will be removed.

Conservation efforts need to focus on maintaining the habitat and minimizing the human influence in this region of Gabon in order to maintain the current forest elephant population and its genetic diversity.

 

 

Reference: EGGERT, L. S., BUIJ, R., LEE, M. E., CAMPBELL, P., DALLMEIER, F., FLEISCHER, R. C., ALONSO, A. and MALDONADO, J. E. (2013), Using Genetic Profiles of African Forest Elephants to Infer Population Structure, Movements, and Habitat Use in a Conservation and Development Landscape in Gabon. Conservation Biology. doi: 10.1111/cobi.12161

  

Photo courtesy of Peter H. Wrege

 

Traditional/Formal article by Shelby Priest

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This entry was posted in Conservation Biology Posts, Conservation Blogs 2012-2013. Bookmark the permalink.

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