Conservation Maven

The jaguar, Panthera onca. Image credit, Pascal Blachier.As with many large, widely dispersed carnivores, jaguars have suffered deep declines in population mainly due to conflict with humans and a decrease in suitable habitat and prey availability.  As predator communities shrink and connectivity between subpopulations deteriorates, species like jaguars risk losing genetic diversity, which manifests in a multitude of ways including a reduction in their ability to adapt to stochastic environmental events. 

In order to protect the relative genetic health of jaguar populations and to establish priorities for habitat conservation, researchers Alan Rabinowitz and Kathy Zeller used a least-cost model to map potential corridors between 90 remaining areas of high jaguar density (which they term jaguar conservation units) throughout Central and South America. They published their findings in a new study in the journal Biological Conservation.

 The researchers layered six environmental variables that affect a jaguar’s ability to move through habitat (elevation, cover type, percent cover, human population density, and proximity to human settlements and roads), and then predicted which paths jaguar are likely to take between the conservation units.  Their findings indicate that 78% of the jaguar’s historical range is still permeable to jaguar migration. The researchers were able to identify 182 potential corridors between populations - 44 of which they determined to be at-risk.

This least-cost model is an innovative tool for examining range-wide, species conservation priorities.  Using known factors of habitat preference among jaguar, the authors were able to predict the most likely routes between established populations through which cats are likely to traverse when searching for new territories.

The authors were also able to identify the areas are of highest concern (given their small size) and the areas most important for the conservation of the species as a whole. For example, the authors identify northern Colombia as an at-risk high priority area that connects Central American and South American jaguar populations.

The model does have some limitations.  The jaguar is a special case in that the metapopulations have already been assessed range-wide.  As the authors point out, the least-cost model should be used only as a reference, and should not replace field surveys, which determine the actual presence / absence of cats within the dispersal corridors.  Additionally, field data about jaguar prey species allow practitioners to make the case for conservation of an area based on the entire ecosystem and not merely a single species.

Furthermore, the authors advise:

For a corridor of any significant scale to have a chance at success and sustainability, conservation practitioners must negotiate a maze of land tenure, land use, jurisdiction issues, and legal issues before deciding upon strategies and approaches.  Each corridor has its own unique set of circumstances, threats, and opportunities that need to be addressed for implementation to occur.  Long-term financial and political commitments are a key component of the process.

--Reviewed by Kelly Stoner

Rabinowitz, A., & Zeller, K. (2010). A range-wide model of landscape connectivity and conservation for the jaguar, Panthera onca Biological Conservation DOI: 10.1016/j.biocon.2010.01.002