Characterizing multispecies connectivity across a transfrontier conservation landscape, Brennan et al. 2020

Connectivity conservation pays attention to landscape connectivity to support animal species’ movements, keep ecological processes intact, and promote biodiversity. While the strategy of conserving connected, non-fragmented areas and respecting animals’ movement patterns is sound, in practice these plans are usually designed around a single species and its needs.

Brennan et al. looked at the limitations of a single-species focus, and evaluated the movement patterns of multiple species. They created connectivity maps for six large mammal species in the Kavango-Zambezi (KAZA) transfrontier conservation area straddling Angola, Zambia, Zimbabwe, Botswana, and Namibia, and assessed how each individual species’ connectivity maps correlated with that of the others.

This then allowed the authors to identify good ‘surrogate species for connectivity’ – that is, species whose connectivity maps were good representations of other species’ movements through the same area. They also took a look at different types of barriers to animal movements and determined that fences were the greatest obstacle to movement, while roads, rivers, and human-settled areas also deterred movement. Finally, they identified connectivity hotspots on the landscape, which are like bottlenecks through which multiple species pass due to barriers elsewhere. These connectivity hotspots are thus essential places to focus conservation efforts.

The researchers found the hyena and African wild dog to be the most apt surrogate species for connectivity, in spite of a popular practice of using elephants to determine the geographic targets of conservation efforts.

In our examination of connectivity across the landscape, female elephants were found to be only weakly correlated with the five other species in our study. Spotted hyena and African wild dog, in contrast, were strongly correlated with the greatest number of species. They also appeared to be complementary surrogates (i.e. they were correlated with different species), in which case combining their connectivity models could further extend the relevancy of connectivity conservation plans to other species. Thus, as both species are also charismatic, wide-ranging species of conservation concern, they may represent good umbrella species for connectivity in the KAZA region [Brennan 2020: 1707].

They went on to say that “while elephants may not be good surrogate species for connectivity across entire landscapes, they may still be effective as a surrogate at local scales where they can help protect local movement pathways or stepping-stone habitats for other species” [Brennan 2020: 1707].

Their conclusion is not that we should stop paying attention to elephants, which serve important ecological functions and are an iconic and culturally significant animal. Rather, we should look for gaps that may arise if we only conserve areas based on elephant movements, and put these techniques of comparing and combining different species’ movement patterns to use. Noting that animal movements and ecological dynamics play out at different scales, from entire landscapes and transnational parks to smaller corridors, they emphasized the importance of looking at connectivity for multiple species at multiple scales. They urged researchers and policy makers to take a more holistic multi-species approach to connectivity conservation.

Salvaging bycatch data for conservation: unexpected benefits of restored grasslands to amphibians in wetland buffer zones and ecological corridors, Mester et al. 2020

This study considers the effect of grassland restoration on amphibian populations in a 760-acre nature reserve – the Egyek-Pusztakócs Marsh System (EPMS) – established on former farmland in Hungary. The study shows that grassland restoration increased habitat range and quality for amphibians, extended hydrological supply, and limited genetic erosion among previously isolated populations. It also illustrates the role of smaller-scale ecological corridors.

Grassland restoration … creates corridors that maintain connectivity among the amphibian (sub)populations in the EPMS but it may also increase the permeability of the landscape to establish and maintain connections to other nearby metapopulations. Grassland restoration can thus also have an effect of minimizing genetic erosion of populations induced by isolation, which is one of the major causes of global amphibian decline [Mester 2020: 7].

Restoration can benefit amphibians by increasing the area of grasslands available for a variety of life activities such as foraging, burrowing, dispersal/ migration, or hiding from predators, aestivation and hibernation in the non-breeding period and by ensuring functional connectivity between wetlands both in the breeding and non-breeding periods [Mester 2020: 9].