Loss of avian phylogenetic diversity in neotropical agricultural systems

Self Cite

Diverse motivations for preserving nature both inspire and hinder its conservation. Optimal conservation strategies may differ radically depending on the objective. For example, creating nature reserves may prevent extinctions through protecting severely threatened species, whereas incentivizing farmland hedgerows may benefit people through bolstering pest-eating or pollinating species. Winwin interventions that satisfy multiple objectives are alluring, but can also be elusive. To achieve better outcomes, we developed and implemented a practical typology of nature conservation framed around seven common conservation objectives. Using an intensively studied bird assemblage in southern Costa Rica as a case study, we applied the typology in the context of biodiversity's most pervasive threat: habitat conversion. We found that rural habitats in a varied tropical landscape, comprising small farms, villages, forest fragments, and forest reserves, provided biodiversity-driven processes that benefit people, such as pollination, seed dispersal, and pest consumption. However, species valued for their rarity, endemism, and evolutionary distinctness declined in farmland. Conserving tropical forest on farmland increased species that international tourists value, but not species discussed in Costa Rican newspapers. Despite these observed trade-offs, our analyses also revealed promising synergies. For example, we found that maintaining forest cover surrounding farms in our study region would likely enhance most conservation objectives at minimal expense to others. Overall, our typology provides a framework for resolving the competing objectives of modern conservation.agriculture | bird | conservation | ecosystem services | multifunctionality F or at least the last century (1, 2), there has been fierce debate over whether nature should be conserved primarily to benefit people or for its own sake. Recently, conservation scientists and practitioners have called for the adoption of a more holistic and inclusive conservation ethic that accepts diverse motivations for conservation (3). In practice, however, limited funding and resources precipitate conflict between individuals and institutions with different motivations for conserving nature. Such conflicts often arise because the best intervention for achieving a chosen conservation objective may fail to achieve another. For example, the influential "biodiversity hotspots" concept directs conservation resources to areas with high rates of habitat loss and high densities of endemic species (4). But hotspots could be delineated using criteria related to virtually any conservation objective. Targeting conservation efforts only on hotspots of extinction or endemism could overlook other species and ecosystems that deliver vital benefits to people (e.g., wetlands that purify water and mitigate floods) (5, 6; but see ref. 7).Because conservationists have disparate and diverse values (8), measuring trade-offs is critical. A typology of conservation objectives could help identify trade-offs...

Section: Discussionsupporting

confidence: 38%

Section: Methodsmentioning

confidence: 99%

Confronting and resolving competing values behind conservation objectives

Karp

Mendenhall

Callaway

et al. 2015

Self Cite

“…Specifically, our models predicting the number of species at a site (α-diversity; Tables S2-S4) coupled with results that describe the kinds of species at a site (β-diversity) support arguments that increasing tree cover around existing forest reserves will lead to small gains in the number of species, but the species gained tend to be rare, unique, and at risk for extinction because of deforestation (2,3,41,42) Our results also suggest that conservation efforts to diversify farmland by increasing tree cover in and around crop fields and pastures leads to large gains in the number of species, but the species gained tend to be common. Our results provide a theoretical basis for aligning conservation strategies to slow extinctions and for boosting some ecosystem services by buffering remaining forests with wildlife-friendly farmland and regenerating forests where politically feasible, given demands to farm the planet (43).…”

Section: Las Crucesmentioning

confidence: 95%

“…1B). These forest elements, together with the agricultural land in which they are embedded, support significant dimensions of biodiversity, whereas the adjacent crop fields and pastures support a different community (2,3).…”

Section: Las Crucesmentioning

confidence: 99%

Quantifying and sustaining biodiversity in tropical agricultural landscapes

Mendenhall

Shields-Estrada

Krishnaswami

et al. 2016

Self Cite

Decision-makers increasingly seek scientific guidance on investing in nature, but biodiversity remains difficult to estimate across diverse landscapes. Here, we develop empirically based models for quantifying biodiversity across space. We focus on agricultural lands in the tropical forest biome, wherein lies the greatest potential to conserve or lose biodiversity. We explore two questions, drawing from empirical research oriented toward pioneering policies in Costa Rica. First, can remotely sensed tree cover serve as a reliable basis for improved estimation of biodiversity, from plots to regions? Second, how does tropical biodiversity change across the land-use gradient from native forest to deforested cropland and pasture? We report on understory plants, nonflying mammals, bats, birds, reptiles, and amphibians. Using data from 67,737 observations of 908 species, we test how tree cover influences biodiversity across space. First, we find that fine-scale mapping of tree cover predicts biodiversity within a taxon-specific radius (of 30-70 m) about a point in the landscape. Second, nearly 50% of the tree cover in our study region is embedded in countryside forest elements, small (typically 0.05-100 ha) clusters or strips of trees on private property. Third, most species use multiple habitat types, including crop fields and pastures (to which 15% of species are restricted), although some taxa depend on forest (57% of species are restricted to forest elements). Our findings are supported by comparisons of 90 studies across Latin America. They provide a basis for a planning tool that guides investments in tropical forest biodiversity similar to those for securing ecosystem services.conservation science | countryside biogeography | ecosystem services | extinctions | species-area relationship W hat is the potential of sustaining biodiversity and ecosystem services in agricultural landscapes? The future of biodiversity hinges on the answer, given the limited scope for expanding protected areas. Moreover, the generation and delivery of many vital ecosystem services occurs on local to regional scales in socialecological systems where people make their livelihoods through cropping, grazing, forestry, and other rural activities. The answer is incomplete, but appears to be "high" (e.g., refs. 1-3). A further question, however, is how can this potential for conservation into the Anthropocene can be realized, with land use, other dimensions of global change, and rates of extinction intensifying rapidly worldwide (4-6) and weak institutions for protecting the global commons (7)?Efforts to secure biodiversity and ecosystem services in rural landscapes are expanding and becoming more sophisticated (e.g., refs. 8 and 9). In the case of ecosystem services, both scientific and policy support for targeting investments have advanced rapidly (10, 11). In China, for example, 200 million people presently are being paid to engage in conservation and restoration activities; since 2000 these investments have resulted in many ecosystem servi...

“…To assess which clades were more similar in WNV response, the number of species with a given WNV response was compared with the means of 10,000 draws of the same number of species from a random pool of remaining species. Families for whom the number of species with a given response was greater than 95% of these draws were considered significantly affiliated with one type of WNV response (38).…”

Section: Methodsmentioning

confidence: 99%

Persistent impacts of West Nile virus on North American bird populations

George

Harrigan

LaManna

et al. 2015

Since its introduction to North America in 1999, West Nile virus (WNV) has had devastating impacts on native host populations, but to date these impacts have been difficult to measure. Using a continental-scale dataset comprised of a quarter-million birds captured over nearly two decades and a recently developed model of WNV risk, we estimated the impact of this emergent disease on the survival of avian populations. We find that populations were negatively affected by WNV in 23 of the 49 species studied (47%). We distinguished two groups of species: those for which WNV negatively impacted survival only during initial spread of the disease (n = 11), and those that show no signs of recovery since disease introduction (n = 12). Results provide a novel example of the taxonomic breadth and persistent impacts of this wildlife disease on a continental scale. Phylogenetic analyses further identify groups (New World sparrows, finches, and vireos) disproportionally affected by temporary or persistent WNV effects, suggesting an evolutionary dimension of disease risk. Identifying the factors affecting the persistence of a disease across host species is critical to mitigating its effects, particularly in a world marked by rapid anthropogenic change.