A proposal for practical and effective biological corridors to connect protected areas in northwest Costa Rica

Abstract

Habitat loss and increases in habitat isolation are causing animal population reductions and extirpations in forested areas of the world. This problem extends to protected areas, which, while often well-conserved, can be too small and isolated to maintain species that exist at low densities and require large contiguous areas of habitat (e.g. some large mammals). Costa Rica has been at the forefront of tropical forest conservation and a large proportion of the country’s land area is currently under some form of protection. One such area is the northwest portion of Costa Rica, which is an extremely biodiverse region with several noteworthy national and privately-owned protected areas. However, each protected area is an isolated island in a sea of deforestation. Within Costa Rica’s existing framework of biological corridors, we propose four sub-corridors as targets for restoration and full protection. These sub-corridors would link five major protected areas in northwest Costa Rica, with all of them linking to larger protected areas in the central portion of the country, while impacting a small number of people who reside within the corridors. After natural or active reforestation of the corridors, the result would be a contiguous protected area of 348,000 ha. The proposed sub-corridors would represent a 3.7% increase in protected area size in the region and only 0.2% of Costa Rica’s total land area. Using the jaguar (Panthera onca) as a model umbrella species, we estimated that each current isolated protected area could support between 8–104 individuals. Assuming lack of dispersal between protected areas (distance between each ranges from 8.1 to 24.9 km), these population sizes are unlikely to be viable in the long term. However, the combined protected areas, connected by biological sub-corridors, could support about 250 jaguars, a population size with a higher probability of surviving. Our study shows that focusing conservation efforts on a relatively small area of Costa Rica could create a large protected area derived from numerous small isolated preserves.

The impacts of agricultural and urban land-use changes on plant and bird biodiversity in Costa Rica (1986–2014)

“…Yet at the same time, Costa Rica went through a reduction in the area of coffee planted mostly in the same Central Valley where urban sprawl creates a growing barrier effect among forest protected areas.We suggest that overcoming these negative trends would require more sustainable farming and agricultural landscapes. Costa Rican scientists and authorities are aware of that, as shown by the approval in 2009 of the new executive decree 33101-MINAE encouraging the National Program of Biological Corridors to improve ecological connectivity(Boraschi 2009, Barquero and Hernández 2015, González 2017, Moran et al 2019, Morera-Beita et al 2021. Unfortunately, our results also show that until 2014 these attempts have not yet succeeded to halt the loss of landscape ecological connectivity.…”

Ecological corridors in Costa Rica: An evaluation applying landscape structure, fragmentation‐connectivity process, and climate adaptation

“…Measures such as habitat restoration and remnant forest retention within ECs are essential to conserve species of smaller home ranges with gregarious behavior and less demanding feeding habits. Management actions seeking greater connectivity within and between ECs (Araya‐Gamboa & Salom‐Pérez, 2016) are oriented toward species with greater spatial demands, such as large carnivore species with migratory movements as well their dietary diversity and food requirements (Moran et al, 2019).…”

“…Several publications assessing the ecological connectivity of ECs have been carried out (Acuña, Molina, & Rodríguez, 2017; Alarcón et al, 2003; Bosselmann, 2012; Chinchilla, 2015; Villate, Canet‐Desanti, & Chassot, 2009) although most studies evaluating ECs are carried out at the individual corridor level, with only one study assessing them on a national scale (Calvo, 2009). In addition, a research was carried out to identify potential sub‐corridor at the actual establish EC's in the Norwest Costa Rica (Moran, Monroe, & Stallcup, 2019).…”

Regional “Bare-Earth” Digital Terrain Model for Costa Rica Based on NASADEM Corrected for Vegetation Bias

“…Much of the area, therefore, has steep slopes. The country is a pioneer among tropical countries in implementing conservation-oriented policies [14]; 27% of the country is protected forested area [15], while 44 ecological corridors cover 38% of the country's surface [16]. Most of the forested territory can be broadly categorised as dry and humid tropical forests, and according to the GFCH2019 model [17], 84% of the area has a vegetation height between 3 and 49 m.…”