Biodiversity and Conservation最新文献

Since the inception of satellite remote sensing as a technology, characterization of forests has been one of its major applications. Characterization of forests at community level is essential for conservation, restoration and sustainable management of biodiversity. Recent advances in remote sensing offer opportunities to observe not only the reflectance spectra of forests from space, but also their phenology and structure. In this study, Earth Observation (EO) datasets were divided into 3 sets: spectral, structural and phenological. Then, Random Forest (RF) algorithm was applied on these 3 datasets along with field inventory-based tree data to generate community classification map of Purna wildlife sanctuary in Gujarat, India. The classification accuracy achieved from the spectral datasets (79.08–87.23%) was better than the phenological dataset (80.94%); and the latter in turn was better than the structural datasets (74.11–81.49%). An RF model with combination of the best predictors from the three datasets increased the classification accuracy upto 90.29%. In case of spectral dataset, the last image before the start of summer monsoon season gave the best accuracy. Also the new spectral bands which first became available in relatively newer satellites contributed significantly more to the model as compared to relatively older spectral bands which have been available in remote sensing satellites for quite some time. Overall, this study develops an empirical framework for mapping tropical tree communities by improving accuracy across the readily available remote sensing datasets and can be upscaled with sufficient field inventory data to generate a national level forest tree community map in India.

Artificial cover objects, made of various materials, have been used for decades for reptile and amphibian surveys, as well as in habitat restoration programs. Their low cost and maintenance demands make them a cost effective and efficient survey method. Since flipping covers does not require special skills, and covers can be uniform in size and material, they can be used as a standardized survey method to negate observer biases. We surveyed the literature in search of studies describing the use of artificial cover objects in situ as part of surveys or habitat restoration efforts of reptiles and amphibians in the twenty-first century. We found 490 studies conducted in 31 countries. Our results show that artificial cover objects are an effective method to sample reptiles and amphibians in terms of both labor and cost. Overall, artificial cover objects used in the studies we surveyed enabled the detection of 357 species belonging to 47 families. Only one study reported animal mortality caused by artificial covers and it also suggested a way to prevent it. No other studies reported direct or indirect injuries or deaths caused by artificial covers. We discuss the efficacy of artificial cover objects in surveying for reptiles and amphibians, and examine their effectiveness when used as part of habitat restoration programs.

Abstract

Effective conservation management depends on the maintenance of key areas that allow population connectivity across the landscape. However, the lack of knowledge of how habitat conversion affects species movement hinders the identification of these areas. Here, we analyzed the impact of habitat fragmentation on landscape connectivity for Leopardus guttulus, a small Neotropical felid threatened by the high habitat fragmentation across the Atlantic Forest, and mapped and ranked the most important core areas and corridors for conservation actions. We also estimated genetic diversity indices and predicted the viability of the current core areas in the future. Our analyses suggest that L. guttulus populations are fragmented, and connectivity links between populations are few and weak. We predict that due to their size, estimated density and low connectivity, some current core areas may not maintain viable populations in the long-term. Also, ongoing land-use changes may further isolate remaining populations, leading to progressive reductions in the populations they support. In this study, we spatially prioritize the most critical areas for L. guttulus conservation and highlighted the urge that exists in the adoption of management measures for its conservation.

Flamingos (Phoenicopteridae) are a distinctive group of birds associated with wetlands, one of the habitats most threatened by human activities. The abstraction of water, mining, agricultural expansion, and rapid urbanization around wetland areas has direct and indirect effects that cause the deterioration of waterbodies, also impacting the species that depend on them for reproduction and survival. Due to their unique features and high popularity, flamingos can also be an important tool for conserving and protecting their wetland habitats, serving as flagship and umbrella species. Nevertheless, due to limited resources, conservation efforts should be prioritized to mitigate major threats and protect species that are more threatened, which necessitates understanding the pressures that most impact these species and their habitats. This systematic review of the literature aimed to search the available literature on flamingo conservation for information on the most common and intense threats and use the information gathered to indicate the conservation priority of the wetlands cited in the literature. The filtering and selection processes resulted in 349 different articles citing 698 different wetlands used by the six species of flamingos in the world. Among the most common threats described were human disturbance and biological resource use, although more drastic changes could be caused by threats such as mining, abstraction of surface and ground water, and pollution. The data showed that European and North American wetlands, many under some form of protection, are highly cited in the literature, while there is less published information available for South American and African wetlands. Our results also highlight the necessity to integrate scientific research, policies and the needs and aspirations of communities that live and depend on these wetlands into land use plans to reverse and mitigate major threats, recover impacted areas, and avoid further wetland habitat loss for flamingos.

Abstract

Snake response to habitat changes is frequently investigated at the species level, but it is still poorly known how snakes respond to habitat changes at the community level and at which spatial scale. Here, we used a multi-model inference approach to evaluate the effects of local and landscape composition (percentage of forest cover and silviculture) and habitat fragmentation (number of forest patches and total edge) on species, functional, and phylogenetic diversity of snake communities in tropical fragmented landscapes. Additionally, we tested whether silviculture acted as an environmental filter for snakes. Species and functional diversity responded primarily to landscape elements: species richness, abundance, and functional diversity decreased with deforestation. In addition, species richness and abundance increased with the proportion of forest and the number of patches in the landscape. In contrast, phylogenetic diversity was driven by the local habitat composition. Although habitat types did not filter entire clades and functional groups, each species tended to have a co-occurring species with similar traits (at landscape level) and a close relative (at both levels) in impacted habitats. In contrast, the co-occurrence of close relatives and functionally similar species was avoided in the native forest. Our findings indicate that snake responses to habitat changes occur on multiple scales and highlight the importance of conserving native forests to maintain multiple components of biodiversity. Strategies for conserving snake diversity in tropical fragmented landscapes should therefore consider management practices at both the local and landscape scales.

Riparian habitats are key landscape elements promoting regional biodiversity, particularly in areas where water availability is scarce. In Mediterranean Iberia, the microclimatic conditions that occur near rivers support the development of humid riparian woodlands, which differ markedly from those growing in equivalent upland areas but share structural and compositional similarities with higher-latitude (Atlantic) formations. However, the effects of this variation on the animal species assemblages inhabiting each woodland type have not been well-documented. We characterized the vegetation of riparian and upland woodlands (general structure and composition) and their avian breeding communities (diversity, climatic and habitat preferences) in 38 sites across mainland Spain to explore how these characteristics changed across a climatic gradient of increasing summer drought. Our results revealed that the prevalence of deciduous woody plants decreased with increasing summer drought. However, this reduction was less steep in riparian than in upland woodlands, reinforcing the idea that Mediterranean riparian areas act as microclimatic refugia where more Atlantic (deciduous) woody species can persist. We also found a lower similarity between riparian and upland bird assemblages in areas with higher indices of summer drought, making riparian woodlands comparatively more diverse than upland woodlands in the Mediterranean. This pattern was partly attributed to the presence of deciduous-tree-related bird species that could not persist in equivalent upland woodlands. These findings suggest that restoring habitat of riparian woodlands would provide refuges with suitable conditions for many woodland species whose persistence on the limit of their distribution range in southern Iberia is threatened by global warming.

Abstract

The endangered Iberian wolf (Canis lupus signatus) populations have been decreasing in Portugal due to a combination of factors such as habitat destruction and human persecution. This is particularly worrying in Central Portugal, where packs are highly fragmented, isolated, and with few individuals. Human-Wildlife-Conflicts occur in this area due to high levels of livestock depredation, an outcome of the low diversity and density of wild prey. As a consequence, human persecution is relatively high and is considered a main threat to wolves’ survival. Through studying public attitudes towards these wolf populations and discerning prevalent patterns, insights can be gained to guide management strategies in mitigating these factors. A total of 222 questionnaires were collected from populations inhabiting Central Portugal, divided into three interest groups (general public, livestock owners, and hunters).We estimated Attitude, Fear, and Knowledge Indexes regarding the wolf. Attitudes towards wolves were positive, with the fear being neutral but the knowledge being low; attitudes tend to be more positive with the decrease of fear and the increase of knowledge, and fear tends to decrease with the increase of knowledge. The main factor negatively influencing attitudes was fear, although age seemed to have more influence on livestock owners’ attitudes. The factors influencing fear included gender, knowledge, and personal experience with wolves. These findings can be used to target specific groups with environmental awareness initiatives, aiming to increase knowledge and reduce sources of fear. It is crucial to develop tailored conservation measures considering stakeholders’ viewpoints to effectively protect the Iberian wolf.

Freshwater gastropods are among the most imperiled organisms on Earth. Yet, they are among the most understudied freshwater taxa. Numerous freshwater gastropod species have gone extinct in the last 100 years, but recent rediscoveries indicate that some species were prematurely declared extinct. Such premature extinction declarations remove legal protections, which could facilitate actual extinction. Thus, research and policy recommendations are needed so surveys provide the best information possible for conservation. Here, we examined the case of Lithasia hubrichti, a freshwater gastropod endemic to the Big Black River in Mississippi that was last seen in 1965. In 2022, a freshwater mollusk survey resulted in finding L. hubrichti alive. An additional survey effort in 2023 that prioritized sampling as many sites as possible in a single day clarified the current range of L. hubrichti. Genomic analyses indicated that the species has persisted with a large population size for thousands of years, rather than ever falling below a survey detection limit. When considering the case of L. hubrichti and other recent freshwater gastropod rediscoveries, we conclude that freshwater gastropod surveys should emphasize sampling as many sites as possible under favorable sampling conditions when targeting rare species, rather than expending high sampling effort at a small number of sites or when stream conditions may impact ability to detect target species. We also advocate for policies that encourage partnerships with landowners, which was required to rediscover L. hubrichti.

Habitat loss, fragmentation, and land conversion for human use are currently the main drivers of biodiversity loss in the Neotropics. Agropastoral and silvicultural activities are especially important, as they have expanded in the last decades due to the increasing demand for global food and wood production. This presents a challenge in developing management strategies that balance biodiversity conservation with productivity, which can only be achieved through a better understanding of biodiversity responses to landscape changes. In this study, we investigated how landscape changes affect the species richness, relative abundance, and species composition of a bat community in a fragmented landscape in southeastern Brazil, using an approach that integrates data from mist-nets and bioacoustics. Forest cover at intermediate and large scales was the best predictor of bat richness and relative abundance, as well as the relative abundance of frugivorous bats. For open and edge space aerial insectivorous bats, landscape variables did not have a strong explanatory power, suggesting that other variables may better predict their relative abundance. Our study highlights the importance of using multiple sampling methods to study Neotropical bats, as well as the importance of the multiscale approach to evaluate landscape effects on biological communities.

Assessing habitat selection is essential to protecting threatened species but also to understand what factors influence species that, although globally not currently in decline, act as flagships of their ecosystems and remain highly vulnerable to human impacts, such as the Eurasian otter. This paper examines otter habitat selection at the river reach scale in two heavily anthropized river basins. Both river basins encompass a wide spectrum of human pressures and biogeographic units, which offers an excellent opportunity to assess otter responses to anthropogenic activities in different scenarios. Through two modelling approaches (structure-agnostic way and a priori hypothesized habitat factors) we demonstrate that otters currently inhabiting these human-dominated landscapes show a trade-off between a preference for highly productive areas and for well-structured and safe areas. We suggest that habitat simplification and human disturbance, which were of minor relevance to the dramatic decline of otter populations in the 20th century, are emerging as potential threats in the context of worldwide increasing land use intensification. Furthermore, we found that otter habitat requirements were remarkably more stringent for breeding site selection than for occurrence, particularly concerning variables related to human disturbance. The results of this work provide tools for integrating ecological criteria oriented to effective otter conservation into river management in human-dominated landscapes, as well as serving as methodological support for lowland river restorations. Our results suggest that long-term otter conservation in anthropized rivers will depend on ensuring the availability of habitat patches that maintain sufficient structural complexity away from intensely outdoor recreational activities.