The importance of forest remnants in human-modified landscapes

In a recently published study, Karp et al. explore the role of working landscapes in the conservation of species diversity. Here, Associate Editor, Ricardo Solar, discusses what their research means for today’s ecologists and conservation scientists.

A Spanish version of this post is available here.

We are witnessing a novel moment in our planet’s history, in which human-driven changes in the Earth’s system are among the most unmanageable risks for biodiversity conservation, as well as human persistence itself. Although it is a challenge for biodiversity to coexist with human-induced changes, these are not the only forces driving biodiversity patterns and shaping communities across the planet. Anthropogenic effects interact with existing natural gradients and therefore applied ecologists have been struggling to understand the conservation value of working landscapes (i.e. human-modified areas, with multiple crop types, pastures, as well as natural areas, such as forests and grasslands). This knowledge is central to reconciling our own existence, as well as activities like food production, with biodiversity conservation.

Costa Rican farms house many bird species, like these Orange-chinned Parakeets (Brotogeris jugularis), but lack sensitive, reserve-affiliated species. Photo supplied by Daniel Karp.

In an effort to understand the role of working landscape biodiversity in species diversity, and the role of such areas for conservation, Dr. Daniel Karp and colleagues surveyed 150 Costa Rican sites, studying birds in remnant forest areas located within both working landscapes and protected areas. They first analysed whether working landscapes are able to sustain similar levels of species richness and species identities relative to protected areas, also targeting if species of special conservation interest are being conserved. They also used this information to guide where restoration actions should be taken in order to maintain a bird community as similar as possible to those in protected areas. From their data set of almost 10,000 individuals and 150 different species, the authors found that species richness remains almost unchanged between working and protected landscapes. However, the identity of species (i.e. species composition) showed marked changes with the amount of forest cover in the landscape, but forest areas located in high-cover working landscapes (+75% forest cover) are virtually indistinguishable of those in protected areas.

Their study implicates that forests located in working landscapes are likely to promote diversity, attaining a community comparable to those in protected areas – at least for birds under Costa Rican national laws and their Payment for Ecosystem Services scheme. The authors provide clear guidance for restoration and conservation priorities, that they argue should focus on wetter areas, as well as in the highly forested landscapes. This would increase the chances of successfully conserving bird diversity in Costa Rica, when new protected areas are no longer an option.

In conclusion, human presence and its consequent activities are imposing unparalleled changes in the planet. Understanding the dynamics of biodiversity persistence in human-dominated landscapes are key to guarantee our own persistence as a species on Earth. The main challenge for modern ecologists and conservation scientists will be to recognize the importance of this new biodiversity filter and its interactions with existing, long-term, natural filters.

Read the full article, Remnant forest in Costa Rican working landscapes fosters bird communities that are indistinguishable from protected areas, in issue 56:7 of Journal of Applied Ecology.

The authors provide further insight into their work in this post.

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