Perspectives in Ecology and Conservation最新文献

Mining and associated infrastructure have been driving land use changes, affecting important biodiversity values and ecosystems services. To balance these impacts, some mining companies implement biodiversity offsets and conservation actions. By simulating a counterfactual land use scenario, this study quantifies the cumulative impacts on biodiversity and ecosystem services resulting from land use and land cover change in a biodiverse region in the Atlantic Forest after implementation of a new mine and its offsets. Our results show that conservation actions at the project scale should be planned considering the regional context, which may influence impacts on areas with high conservation priority as well as the ecosystem services budget. The comparison among scenarios reveals that raw materials and carbon storage are the least affected budgets, while fresh water, pollination, and local climate and air quality regulation are most impacted. Areas with high conservation priority could be benefited with increased forest cover in future, whilst the demand for some ecosystem services can be affected. Counterfactual baselines could support conservation targets by prioritizing protection and restoration measures – especially offset planning – for halting pressures on biodiversity and balancing ecosystem services supply and demand.

To preserve biodiversity, the Brazilian law postulates that rural properties must keep a percentage of native vegetation cover, denominated as “Legal Reserve” (LR). Recent political efforts are being made to disoblige the farmer to keep the LRs. In this study we evaluated the role of LRs in ensuring the ant biodiversity on LRs and soybean plantations. Ants were collected in 42 landscapes within Amazonian forests and Cerrado savannahs and the transition vegetation between them. In each landscape, sets of pitfall traps were placed in a paired design, in the Legal Reserve area and in the adjacent soybean cultivation matrix. As expected, the number of species was extremely lower on soybean plantations. Despite richness, we observed strong turnover between the LRs and plantations. The landscape types on which the Legal Reserve was inserted did not influence the number, but did influence the composition of species. Also, the similarity among samples decay with geographic distance only on LRs. Our results show the importance of the maintenance of Legal Reserve areas for the ants and associated biodiversity in agro-ecosystems. This fact reinforces the need to preserve the Legal Reserves as described in Brazilian law.

Understanding how biological communities respond to human-caused landscape disturbances is urgently needed to identify optimal spatial scenarios for preserving biodiversity in anthropogenic landscapes. Forest loss is increasingly cited as a major disturbance in these landscapes, but its impact on biodiversity in mountain regions with high endemism is not well understood. Here we evaluated how bird species diversity responds to forest loss in ‘La Montaña’ mountain region of Guerrero State, Mexico. We separately assessed the complete bird assemblage, and the diversity and spatial distribution of three different ecological groups (forest-specialists, habitat-generalists, and disturbance-adapted species) in the whole landscape mosaic. We found that the diversity of the complete assemblage decreased linearly with forest loss. However, species responses to forest loss differed among ecological groups, with the diversity of forest-specialist and habitat-generalist species increasing in more forested landscapes, and the diversity of disturbance-adapted species following the opposite pattern. Similarly, the proportion of sites occupied by forest-specialist birds decreased with forest loss, but site occupancy by habitat-generalist and disturbance-adapted birds was independent from forest cover. Our findings highlight that the optimal landscape scenarios for preserving bird biodiversity in general and forest species in particular, are those that maintain as much forest cover as possible.

Human activity is depleting biodiversity, and road networks are directly contributing to this trend due to roadkill. Nevertheless, few studies empirically estimated the impact of roadkill on wildlife populations. We integrated information on roadkill rates, population abundance, and animal movement to estimate the survival rates and the proportion of the population likely to be extirpated due to roadkill, using giant anteater (Myrmecophaga tridactyla) as model species. We then assessed the consequent implications of roadkill on population persistence using population viability analysis (PVA). The yearly survival rate of resident anteaters inhabiting road vicinity areas (0.78; CI: 0.62−0.97) was considerably lower than for those living far from roads (0.95; CI:0.86–1.00). The real number of anteaters being road-killed is considerably higher than the one recorded in previous studies (by a factor of 2.4), with ca. 20% of the population inhabiting road vicinity areas being road-killed every year. According to PVA results, roadkill can greatly affect the persistence of the giant anteater populations by reducing the growth rate down to null or negative values. This study confirms that roads have significant impacts on local population persistence. Such impacts are likely to be common to other large mammals, calling for effective mitigation to reduce roadkill rates.

Protected areas can prevent forest loss, but their effects on forest fragmentation and forest regrowth are poorly understood. Furthermore, the importance of protected areas in shaping these forest spatial changes may depend on different socioeconomic drivers (e.g. population size, distance to cities, proportion of local people working in non-farm occupation), but the empirical evidence on such dependence is very scarce. Here, we used contra factual technics to assess whether biosphere reserves (n = 19) in the Mesoamerican biodiversity hotspot can reduce forest loss and fragmentation and promote forest regrowth during the period 2000–2020. We used satellite imagery and governmental data to assess the socioeconomic factors driving these changes. Particularly, using multimodel inference analysis, we tested whether higher non-farm occupation, combined with low demographic pressures, reduces forest loss and fragmentation and promotes forest regrowth. We found that reserves reduce forest loss and preserve less-fragmented configurations, however, they neither reduce fragmentation rate nor promote forest regrowth. Forest loss rate inside the reserves decreased as non-farm occupation enhanced and the density of rural settlements decreased. Therefore, promoting higher opportunities in non-farm economic activities and planning rural settlements distribution around reserves could help to increase the effectiveness of reserves for forest conservation.

Coral reefs are in global decline due to unprecedented anthropogenic threats that have escalated and accumulated over decades to centuries. In order to assess the magnitude and drivers of changes on reefs, it is necessary to reconstruct the history of changes of these ecosystems over this longer time scale. We compiled and assessed historical records of naturalists that visited Abrolhos reefs over the last 202 years, and compared a 160-year-old nautical chart with modern charts to quantify losses in the spatial extent of coastal reefs in the Abrolhos Bank, Brazil. We found a 28% loss in the overall spatial extent of inshore reefs, with some areas experiencing declines up to 49% over the past 160 years. Such reefs with more dramatic changes (Guaratibas reefs) are the closest to the coast (∼7 km), where local impacts such as the past extraction of coral for lime since the 19^th century, as well as increased coastal sedimentation and siltation due to deforestation are concentrated and that, combined, may have caused the observed decline. Collectively, this set of historical information captures coral reef changes over time, and helps update conservation and restoration goals for the Abrolhos reefs seascape.

Disturbances are key events in ecological systems, strongly impacting biological communities. This study disentangles the effects of a chronic (flood) and acute (fire) disturbance to determine their interactive effects on ant species richness and composition at different temporal scales. For this, we sampled ground-dwelling ants with pitfall traps on native grasslands in the Pantanal wetland, one of the world's largest floodplains. We sampled ants ten days (short-term), one year (medium-term), and four years (long-term) after fire and at varying elevations (a surrogate for the time that these areas remain flooded). We found that fire was the dominant factor in determining ant community patterns in flooded areas. In the short-term, fire substantially changed species composition and increased species richness. However, these effects decreased at one year and disappeared after four years, demonstrating the ant community’s resilience. Elevation and, consequently, flooding, did not influence any measured parameter, indicating that the ant species are adapted to colonize other areas rapidly or survive in such flooded habitats. Our results suggest that Pantanal ant communities can recover from acute fire disturbances after some years. However, increasing fire frequency caused by global climatic changes and recent Brazilian environmental policy misconducts would probably compromise the observed resilience.

Assessing where wildlife populations are at risk from future habitat loss is particularly important for land-use planning and avoiding biodiversity declines. Combining projections of future deforestation with species density information provides an improved way to anticipate such declines. Using the critically endangered Bornean orangutan (Pongo pygmaeus) as a case study we applied a spatio-temporally explicit deforestation model to forest loss data from 2001 to 2017 and projected future impacts on orangutans to the 2030s. Our projections point to continued deforestation across the island, amounting to a potential loss of forest habitat for 26,200 orangutans. Populations currently persisting in forests gazetted for industrial timber and oil palm concessions, or unprotected forests outside of concessions, were projected to experience the worst losses within the next 15 years, amounting to 15,400 individuals. Our analysis indicates the importance of protecting orangutan habitat in plantation landscapes, maintaining protected areas and efforts to prevent the conversion of logged forests for the survival of highly vulnerable wildlife. The modeling framework could be expanded to other species with available density or occurrence data. Our findings highlight that species conservation should not only act on the current information, but also anticipate future changes to be effective.

Grasslands have been subject to contraction and fragmentation processes worldwide, mainly due to their transformation into commercial tree plantations and agricultural lands. Identifying the remaining grasslands areas and the drivers of its fragmentation constitute an important step towards their appreciation, conservation and sustainability monitoring. The Eastern Plains of Uruguay constitute a region of recognized national and international conservation importance, but rice cultivation has spread extensively over the last 60 years, resulting in a strong transformation of its natural biomes. Our objectives were to map natural grasslands remnants in this complex landscape characterized by a high presence of different post-agricultural stages of vegetation; to quantify grassland fragmentation and its spatial variability in the landscape; and to identify the main drivers of the fragmentation process. We intersected a current supervised classification of the Eastern Plains of Uruguay (743,600 ha) with a mask of croplands from the previous ten years to discriminate grasslands remnants. We quantified the landscape fragmentation and described the relative contribution of different biophysical and anthropogenic factors in grasslands spatial configuration. Our results showed that natural grassland currently occupies only 21% of the Eastern Plains surface and it is in an advanced stage of fragmentation, comparable to that of the most historically transformed regions of the Rio de la Plata Grasslands. A few variables that determine the expansion of agriculture (large cadastral parcels size, high road network density and low topographical variation) drive the fragmentation process, relegating grassland to places with unfavorable characteristics for the development of rice cultivation.

Here, we investigate the influence of scale on different drivers influencing the occurrence of the chytrid fungus, Batrachochytrium dendrobatidis (Bd), in the Atlantic Forest, Brazil. We used gridded values of proxies of the abiotic, biotic and anthropogenic components of landscapes where Bd infects amphibians. Building upon disease prevalence data obtained from a previous work, we fitted GLS multiple regression models using extracted values of the three predictors for each prevalence centroid in space, explicitly controlling for spatial autocorrelation among predictors. To test for the effect of scale on driving the macroecology of Bd infection, we performed tests at different spatial scales. We then used model selection procedures to evaluate the relative contribution of the different predictors on the occurrence of the fungus. The Human Footprint Index better explained a pathogenic species occurrence than largely studied biotic and abiotic factors (i.e., host species distribution and minimum monthly potential evapotranspiration). That effect was, however, not observed at landscape scale, where we found no difference among the relative influence of predictors. Our results indicate that human-mediated impacts on environments can be strong drivers of spread of infectious diseases on native faunas worldwide, thus, suggesting that anthropogenic landscapes may create favourable conditions for the occurrence of this and other infectious diseases.