Assessing the benefits of Transboundary Protected Areas: a questionnaire survey in the Americas and the Caribbean.

There are more than 3000 protected areas (PAs) situated on or near international boundaries, and amongst them there is an increasing trend towards the establishment of transboundary cooperation initiatives. Proponents of Transboundary PAs (TBPAs) highlight the potential for biodiversity protection through spatial, management and socio-economic benefits. However, there have been few formal studies that assess these benefits. It is possible that the relaxation of boundary controls to optimise transboundary connectivity may increase the risk of impacts from invasive species or illegal human incursion. We sought to investigate the validity of these proposed benefits and potential risks through a questionnaire survey of 113 PAs, of which 39 responded and met our inclusion criteria. 82% felt that transboundary cooperation has benefits for biodiversity and, across PAs, the self-reported level of transboundary communication was positively associated with some improved spatial, management and socio-economic benefits. However, 26% of PAs reported that they never communicated with their internationally adjoining protected area, indicating unrealised potential for greater gains.

Conservation on international boundaries: the impact of security barriers on selected terrestrial mammals in four protected areas in Arizona, USA.

Several thousand terrestrial protected areas (PAs) lie on international boundaries. Because international boundaries can be focal points for trade, illegal activity and development, such PAs can be vulnerable to a range of anthropogenic threats. There is an increasing trend towards the erection of international boundary infrastructure (including fences, barriers and ditches) in many parts of the world, which may reduce the risk of these anthropogenic threats to some PAs. However this may restrict home range and access to resources for some native species. We sought to understand the impacts of these two different types of threat by using camera traps to measure the activity level of humans, native and invasive mammals in four US PAs on the Mexican international boundary. Comparisons were made between treatment areas with barriers and those without. Results showed that puma and coati were more likely to appear in treatment areas without barriers, whereas humans were not observed more frequently in one treatment area over another. The suggestion is that the intermittent fencing present in this part of the world does affect some native species, but does not necessarily restrict the movement of humans (including illegal migrants), who may negatively impact native species.