Using habitat connectivity models to save endangered species: a case study for the San Martin titi monkey, in northern Peru
The latest EC Perspectives paper from Environmental Conservation is entitled ‘Rapid conservation assessment for endangered species using habitat connectivity models‘ by Danica Schaffer-Smith, Jennifer J. Swenson and Antonio J. Bóveda-Penalba.
Scientists estimate that extinction is ocurring at 1000x its natural rate, and tropical regions are considered to have the highest risk of species loss. Sophisticated tools to inform recovery programs, such as population viability, metapopulation dynamics, and gene flow analyses have limited utility in the tropics, where there is an overwhelming lack of data for most species, and high rates of ongoing habitat loss and degradation. Fortunately, habitat connectivity models can provide an alternative source of information for conservation planning.
The critically endangered San Martín titi monkey (Callicebus oenanthe) is endemic to the San Martín department in northern Peru, and presents an urgent case study that is well-suited to connectivity analysis. C. oenanthe’s lowland forest habitat is not contained within national protected areas, and continues to be threatened by high rates of deforestation. This arboreal primate requires a connected canopy for movement; using small forest fragments and narrow tree corridors to move through the landscape. My doctoral advisor, Dr. Jennifer Swenson, first encountered this charismatic species in a small forest patch behind a discotheque, while she was working in San Martín with NatureServe in 2005. Since that time, the Peruvian non-profit Proyecto Mono Tocón (PMT; monotocon.org) has grown a program to research the status of several key species, work with local communities to establish new conservation areas, and conduct environmental education in the region.
Working with PMT, we modeled the range of C. oenanthe, mapped remaining forest from satellite imagery, and executed a study of potential connectivity in the Alto Mayo Valley to identify priority forest patches for conservation. This portion of C. oenanthe’s range is particularly constrained, by surrounding high mountains, broad rivers and extensive deforestation. Fieldwork to verify land cover led us through cattle pastures, rice fields, verdant orchards of coffee, cacao and fruit trees, through waist deep water in flooded forests, and into the thick fern and forest-covered foothills of the Andes. Although we visited during the ‘dry’ season it was cloudy and rainy nearly every day, making it abundantly clear why satellite-based analysis has previously been limited in this region!
We hope that demonstrating how connectivity analysis approaches can be applied for conservation will extend their use by practitioners. We often lack sufficient information for tropical species, yet we risk losing them by inaction. Our approach can support conservation and restoration plans for such at-risk, understudied species.
Duke University has continued working with PMT through two Nicholas School of the Environment Master’s of Environmental Management projects. Maggie Ernest (MEM ’15) continued landcover mapping to achieve a map of remaining forest for the entirety of C. oenanthe’s range. Current MEM student Nathan Walker is pursuing a range-wide connectivity analysis and is also comparing multiple methods in terms of their sensitivity to the underlying land cover map and assumptions about species movement and dispersal. It is important that we better understand the uncertainties in connectivity analyses in order to make the most informed decisions.
The full paper ‘Rapid conservation assessment for endangered species using habitat connectivity models‘ is freely available in Environmental Conservation.