Biodiversity and Conservation最新文献

The decline of pollinator insects in various parts of the world has increased the interest in studies on bee sampling. Because pollinator management and conservation policies depend on data representing their communities, knowledge of the systematic bias of sampling methods in relation to surrounding habitat is fundamental. This study examined the performance of standardized transect walks and colored pan traps considering differences in bee species richness, diversity, and composition, and the potential bias due to a different availability of floral sources throughout seasons. The study was conducted in a minor outlying island (Asinara, Italy), a natural park characterized by the prevalence of natural or semi-natural habitats and an Oceanic Pluviseasonal Mediterranean bioclimate. We found that transect and pan trap methods reflected different bee communities based on taxonomic families, genera, and species. In general, the transect method captured more varied samples than pan traps, despite the significantly lower number of individuals captured on transects. Moreover, pan traps captured more bees as floral abundance decreased, whereas transects showed greater bee abundance, richness, and diversity with increasing floral resource availability. In addition, 18 species out of the 68 observed in total were caught exclusively with pan traps, especially in July–October, when transect catches decreased due to substantial bloom reduction. Therefore, alternating the two methods according to season (i.e., transect in late winter-spring and pan trap in summer-autumn) might be the most suitable trade-off to obtain a better representation of the bee community by limiting sampling efforts and the negative impact on bee fauna.

Global biodiversity is declining at rates never seen before. At the same time, resources directed at conservation planning still fall orders of magnitude short. Thus, efficient allocation of resources is needed to prioritize regions that can shelter more biodiversity. A usual approach to identify priority areas for conservation is to map species distribution and use this information as input in spatial prioritization proceedings. Since data on common species are more readily available, final maps of priority areas for conservation are heavily biased towards this group, overlooking rare species. Thus, we created a ranking of priority maps for common and rare tree species, separately, aiming to comprehend if prioritizing areas for the conservation of common trees is enough to protect rare trees all at once. Additionally, we overlapped our priority maps with maps of current protected areas (PAs) to identify if the latter already cover areas designated in our models. Our results show that common tree species can act as surrogates for rare tree species since priority maps for both groups overlap with more than 70% of their area. Yet, most of the current PAs do not cover significant areas for protecting tree species, revealing an urgent need to expand or create new PAs to properly safeguard the local biodiversity.

Citizen-collected data are used to describe ecological patterns and to obtain information about the distribution and trends of fauna and flora to inform management and conservation actions worldwide. However, considering the logistical and financial aspects, data should be collected in a cost-effective way. In addition, informed by the spatio-temporal distribution of observations, under-, and oversampled areas can be identified to guide future sampling efforts. Here, we classify 37,161 observations of South American Actinopterygii submitted to iNaturalist, occurring in both coastal and inland water bodies. We consider the status of the fish (live/dead), the characteristics (taxonomy and habitat) of the species and the circumstances of the observation (e.g., during fishing or diving). We test whether adding opportunistic observations increases species diversity, i.e., if observations of dead fish and fishing-related data add information to traditionally collected occurrence data (i.e. those of live fish observed during diving). Our dataset contained 2,377 species of 206 families, representing 24% of all South American ray-finned fish species. Dead individuals and observations related to fishing on average contributed 37% and 33% of annual observed species richness, respectively and added 151 unique species not recorded live or under circumstances not related to fishing. We found that for dead fish the rate of validation by peers and experts on the platform had been 20% lower compared to that of live individuals. We argue that recording organisms observed under different circumstances and in different conditions improves our knowledge of biodiversity. Demonstrating the value of all observations can encourage volunteers to make their data collection more inclusive.

In India, human-elephant conflict has been on the rise for the last few decades. The situation is worse in the state of Assam, where 5719 elephants are present, and the density of elephants is greater than that of other areas. Most of the elephant habitats in the state are fragmented or intermingled with human-used lands. As a result, human-elephant conflict (HEC) has been increasing in the state. Each year, an average of 80 elephants and 70 humans die in the state because of HEC. Most of these conflicts occur during the paddy harvesting season. At that time of year, the elephants come out from their habitats and take refuge in forest patches and tea gardens near agricultural fields and raid crops at night. Different methods have been adopted to identify conflict-affected areas, but none of the studies have tried to identify all the HEC-affected areas in the state. Here, we provide a rapid appraisal approach for identifying HEC hotspots in the state by using published news information as the primary source of data. A total of 216 villages were identified as HEC-affected areas in Assam. The identified areas can be used to understand site-specific problems and for HEC mitigation practices, as these areas are currently limited to only a few areas.

Deforestation is linked to the increasing prevalence of small forest fragments worldwide and an associated loss in functional diversity. However, our long-term understanding on how biodiversity and functional roles respond in such isolated fragments is limited, especially in Southeast Asia. We compared the bird community in a small primary rainforest fragment in the Singapore Botanic Gardens, a UNESCO World Heritage Site, using historical records in 1898 and contemporary surveys conducted in 1998 and 2018–2021. Species composition was expectedly dissimilar between the 1898 and contemporary bird communities (50%), driven mostly by turnover (45.5%) rather than nestedness (4.5%). Despite the changes in community composition and species extirpations, both species richness and functional diversity were retained. Our results suggest that small forest fragments can form novel bird communities that are functionally similar to previous communities that inhabited the fragment, leading to the retention of functional diversity. Such functional redundancy may be encouraged through habitat restoration initiatives adjacent to fragmented forests.

Climate change is a major threat to biodiversity as many species are facing the risk of extinction due to their inability to adapt to the changes in temperature, precipitation, and other environmental variables. The impact of climate change on the habitat distribution of Taxus wallichiana, a medicinally important endangered tree species, has not been studied specifically for the Indian Himalayan region (IHR). We assessed the vulnerability of the species to climate change using Ecological Niche Modeling (ENM) in conjunction with two latest global climate models (GCMs) viz., HadGEM3-GC31-LL and IPSL-CM6A-LR, under two future scenarios i.e. Shared Socioeconomic Pathways (SSPs) - SSP126 and SSP585 from Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, 2023. Based on current distribution of the species and bioclimatic conditions., the Maxent-derived projections indicated significant reduction in its suitable habitat in IHR. Under the moderate scenario i.e. SSP126, suitable habitats are expected to decrease to 6,313,494 ha (10.62% of the total geographical area of IHR) with HadGEM3-GC31-LL and to 4,161,437 ha (7.00%) with IPSL-CM6A-LR from the present distribution area of 8,132,637 ha (13.68%). Under high-emission SSP585 scenario, the predicted habitat area is expected to decline to 4,833,212 ha (8.13%) with HadGEM3-GC31-LL and to 3,204,306 ha (5.39%) with IPSL-CM6A-LR.Annual mean temperature, isothermality, and annual precipitation were important environmental variables impacting the species distribution and models’ predictive capacity. The model outputs clearly predict a gloomy picture under both the future climate scenarios for T. wallichiana emphasizing the need for a targeted conservation effort for the species. .

Beyond preferences for particular species of tree, bark-foraging birds are associated with various tree characteristics such as decay stage, trunk diameter, or bark roughness. Our objectives were to study the winter foraging ecology of different bark-foraging bird species in the highly diverse floodplain forests of Donau-Auen National Park (Austria) by examining the importance of tree species and characteristics. We used 'first-foraging' observations on the great spotted woodpecker (Dendrocopos major), middle spotted woodpecker (Leiopicus medius), Eurasian nuthatch (Sitta europaea), treecreepers (Certhia spp.), great tit (Parus major), Eurasian blue tit (Cyanistes caeruleus), and marsh tit (Poecile palustris). We examined bird-tree relationships with a bird-plant network approach, where we compared traits of trees and their preferences among avian species. The five most important tree species relative to distance-weighted fragmentation were European white elm (Ulmus laevis), pedunculate oak (Quercus robur), common ash (Fraxinus excelsior), and white and black poplar (Populus alba, P. nigra). Avian taxa differed only in the use of tree condition, where woodpeckers used decayed and dead trees more than tits. Most species preferred trees of larger trunk diameter with rougher bark. We suspect that changes in these highly diverse floodplain forest stands will eventually lead to changes in bark-foraging bird assemblages. For the protection of such highly diverse floodplain forests, conservation-based water management practices will be crucial to maintaining a sufficient groundwater table. Our findings also suggest that forest management practices should focus on more diverse commercial forest stands with a critical amount of secondary tree species, a variety of size classes, varying tree conditions, and species with different bark roughness classes.

Organismal colours have long captivated and inspired naturalists and scientists. Since colours depend on the life history of a species, it is expected that they respond to environmental changes, especially in an increasingly anthropized world. Aiming to evaluate how this trait responds to different anthropogenic disturbances, we assess wing colour aspects of fruit-feeding butterflies sampled in Atlantic Forest remnants. These remnants, with well-defined understory and canopy, are crossed by artificial edges and surround exotic pine silviculture areas of different ages, representing landscapes commonly found in the subtropical Atlantic Forest. We obtained colour measurements of brightness, saturation, contrast, colour diversity and heterogeneity, and the presence of eyespots and iridescence for dorsal and ventral wing surfaces of 47 fruit-feeding butterfly species. We evaluated colour trait distribution and abundance in the distinct native (understory and canopy) and anthropized (edge, old and young Pinus) habitats, and hypothesised that butterfly assemblage colouration will differ in each habitat due to biotic and abiotic differences. In addition, butterfly assemblages in anthropized environments should present less diverse colour traits due to the pressures generated by anthropogenic actions, like microclimate changes and higher exposure to predation. As expected, the natural environments have butterflies with diverse colours and unique contrast colour traits. These patterns are not found in anthropized ones despite artificial edges presenting brighter and even more diverse colours. However, pine silviculture areas present butterflies with less diverse colours, leading the most colourful species to disappear. We demonstrate that different anthropogenic disturbances can impact butterfly colouration. Our results reinforce the close relationship between butterfly colouration and the environment, highlighting that colours can be used as bioindicators for conservation purposes, representing a useful form of functional biodiversity.

Conservation and management of drylands is a global challenge. Key attributes of these ecosystems, such as dominant vegetation including shrubs, can provide a crucial mechanism to inform conservation strategies. The shrub species Ephedra californica and Larrea tridentata are common native shrub species within the deserts of California and frequently benefit other plant and animal species. Here, we tested the hypothesis that shrubs support reptile and amphibian communities through relative increases in available habitat, estimated through increasing shrub densities at the site level. Reported occurrence data from the Global Biodiversity Information Facility (GBIF) and high-resolution satellite images were used to test for local-to-regional patterns in reptile and amphibian distribution and diversity by shrub densities at sites. At 43 distinct sites, the relationship between shrub density and reported reptile and amphibian communities was also tested. A total of 71 reptile and amphibian species were reported regionally. Increases in shrub density across sites positively influenced the relative abundance and richness of reptiles and amphibians observed. Moreover, increasing shrub density also had a positive influence on species evenness. Aridity differences between sites did not significantly influence the relationship between shrub density and reptiles and amphibians suggesting that the relationship was robust. This study highlights the importance of foundational shrub species in supporting reptile and amphibian communities in arid and semi-arid regions. Large-scale patterns of biodiversity in deserts can be supported by positive plant-animal interactions including small islands of fertility and resources for animals in the context of a warming climate.

Eradication of invasive alien species (IAS) is often proposed to restore invaded ecosystems, with information on subsequent ecosystem recovery key to conservation policies. Although ants perform major ecological functions in the ecosystem, their response to IAS eradication has received relatively little monitoring. This study investigated ant response to iceplant (Carpobrotus spp.) and black rat (Rattus rattus) eradications on the small Mediterranean island of Bagaud (Var, France). Ant communities were monitored over a ten-year period, including two years before eradications, at six different sites: two invaded by iceplants, two under high rat pressure, and two native vegetation sites without intervention. We found inter-annual variations in ant communities but no before-after eradication trend at both native vegetation and rat eradication sites. However, there was a clear increase in ant species richness and abundance score after the iceplant eradication. A core of common Mediterranean species, including Pheidole pallidula, Messor bouvieri, and Plagiolepis pygmaea, increased their foraging activity after the removal. As xerophilous and thermophilous species they would benefit from the return of native vegetation with possibly warmer and dryer microclimatic conditions, but also from habitat and resource diversification. The trend was even stronger on the denser and thicker iceplant eradication patch. Our results emphasize the relevance of implementing ant monitoring to evaluate the effectiveness of such restoration and conservation strategies.