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1.
Presence-only models can aid conservation and management of threatened, elusive species. We developed a Maxent model for the rare cerambycid beetle Rosalia longicorn Rosalia alpina L. in Italy and neighbouring regions and identified the variables best explaining the species’ occurrence on a large scale. Once successfully validated, we used the model to (a) evaluate the current degree of fragmentation of R. alpina range in Italy; and (b) quantify the amount of the Italian territory with the highest probability of beetle presence within the existing national conservation areas (Natura 2000 network, parks and reserves). Low (<0.5) probability scores of R. alpina presence corresponded to 89% of the total area considered, whereas high scores (>0.9) covered only 2.5%. R. alpina was predicted to occur mostly in broadleaved deciduous forest at 1000–1700 m a.s.l. with warm maximum spring temperatures and May and November precipitation >80 mm. We found a high degree of fragmentation; gaps were mainly covered with farmland or other unsuitable habitat. Over 52% of potential habitat is unprotected. While the Natura 2000 network protects 42% of potential habitat, parks and reserve covers less than 29%. To preserve R. alpina, we urge to create, or restore, forest corridors to bridge the otherwise impermeable gaps our model detected and grant protection to the still largely unprotected area of the Italian territory e.g. by including it in further Natura 2000 sites. Models such as ours may also help focus field surveys in selected areas to save resources and increase survey success.  相似文献   

2.
The Bonelli’s eagle (BE) is considered by the European Union as a high-priority species for conservation in the Valencian Community (East of Spain). However, in 2006 the European Union opened a legal procedure against the Spanish Kingdom, accused of lacking of an adequate network of special protected areas (SPAs) to preserve the BE in the region. Here we evaluate whether important bird areas (IBAs) and SPAs network is enough to preserve this species, on the basis of a thorough analysis of habitat preferences. A GAP analysis is performed to conduct a revision of current SPAs and BirdLife proposed IBAs. Our results suggest that the current network of SPAs becomes insufficient to protect the BE. The IBAs network, although improves the current network of SPAs, increasing the percentage of BE potential habitat included, also results inadequate. We propose a new SPAs network according to the potential suitable habitat for the species. Given the trade-off between financial investment and the conservation of biodiversity, we propose to maximize the surface of potential habitat included in the protected network minimizing the surface of the region that would be necessary to protect, thus avoiding an unnecessary expense and otherwise unrealistic results.  相似文献   

3.
The black bear Ursus americanus is an endangered species in Mexico. Its historical distribution has decreased by approximately 80% although its current distribution is not known with precision; it is only reported to be present in the mountains of Northern Mexico. This study proposes two ensemble models: Mexicós black bear (a) potential distribution compared with Natural Protected Areas (NPAs); and, (b) persistence areas for 2024. The current distribution variables are coniferous forest, elevation and dry forest. Suitable habitat for black bear (354,047 km2, 18.07% of the country) was found mainly in the north of the Sonoran biogeographical zone, along the Sierra Madre Occidental, the center and south of the Sierra Madre Oriental and some northern regions of the Altiplano Norte. Comparing these areas with NPAs documented that only 12.41% of potential distribution coincided with current suitable habitat. There are unprotected areas in Sierra Madre Occidental center and central and southern of Sierra Madre Oriental. The model for 2024 indicates a reduction of suitable habitat of 64.5%, mainly in the northern Sonoran zone and the center Sierra Madre Occidental. On the other hand, areas that will persist (125,673 km2) are located along the two main mountain ranges of Mexico. Identification of these sites will allow strengthening of long-term conservation strategies.  相似文献   

4.
A key conservation biology tool is the information on the geographic distribution of species as well as the variables driving those patterns. Here, we used maximum entropy modeling, MaxEnt, to model the total potential distribution of Tapirus terrestris, classified as “Vulnerable” on the IUCN Red List of Threatened Species. In this study, we recorded 117 occurrence records and considered 18 environmental variables. The total potential distribution area covers 96,055.6 km2, meaning 12.3 % of the territory of the Peruvian Amazon, with “high potential” habitat covering 3,891.36 km2, “moderate potential” habitat covering 22,849.5 km2, and “low potential” habitat covering 69,314.7 km2. Natural Protected Areas (NPAs) shelter 32.2 % (30,966.2 km2) of the total potential distribution area of the species, being the Bahuaja Sonene and Manu National Parks, the NPAs with the largest total potential distribution, 8,220.2 km2 and 7,619.7 km2 respectively. Eventually, 67.8 % (65,089.4 km2) of the total potential distribution were identified without any type of protection category by SINANPE and its complementary categories; therefore, we consider this area as a priority for the conservation of T. terrestris in Peru.  相似文献   

5.
The well-known presence of mahseers, Neolissochilus soroides (Cyprinidae), in forested streams in eastern Thailand has attracted many visitors to protected areas for several decades. Because of its historical high abundance, this species was never considered of conservation concern. In this study, the authors revealed that mahseers are very limited to upstream areas in mountains facing the Gulf of Thailand and are now solely confined to habitats within protected areas. The fish were sampled below seven waterfalls in four national parks. All individuals were analysed using a fragment of the mitochondrial DNA cytochrome b gene and eight nuclear microsatellite DNA loci to uncover spatial genetic patterns. Cytochrome b data showed very low genetic diversity but indicated strong genetic differentiation between the most distant Klong Kaeo (KK) population and the other populations. The more variable microsatellite DNA markers showed moderate level of genetic diversity compared to other mahseers but revealed limited gene flow among all locations (overall FST = 0.25, P < 0.05). In addition, significant correlation was found between genetic and geographic distances (P < 0.05). Genetic bottleneck analyses provided an insight into evolutionary history in N. soroides that may have experienced past reduction in population size. As eastern Thailand is a relatively heavily populated region, habitat modification in lowland areas is inevitable, and it will have consequences for species that prefer fast-flowing and clear water. Protected areas therefore provide valuable sanctuaries for N. soroides in headwater streams.  相似文献   

6.
The conservation of biodiversity in Europe is defined by Directive 92/43/EEC – commonly known as the Habitats Directive – relating to the conservation of natural habitats and of wild flora and fauna. This Directive established the creation of an ecological network of European protected areas – the Natura 2000 network – , and also recognised the need to manage these areas to maintain their “favourable conservation status”.This paper proposes a methodology which enables the conservation of biodiversity to be integrated into the management of Natura 2000 forest spaces. The methodology comprises an “environmental diagnosis” in three phases. The first phase evaluates the current conservation status of habitats using the following criteria: vital functions; floristic richness; forest structure; area occupied by the habitat; and recovery capacity. The second phase assesses the fragility of the space to determine the degree of vulnerability of habitats. This involves evaluating the fire hazard, erosion hazard, and the fragility of the vegetation. The last phase combines the two previous ones to generate management areas (optimum, intermediate or unfavourable) and to prioritise management actions.This methodology was applied in a protected forest area in the Natura 2000 network, located in Avila (Spain). Different management areas were generated for biodiversity conservation, and each habitat was associated to one of them. Finally, actions were prioritised and designed to raise the habitats to a “favourable conservation status”.  相似文献   

7.
8.
The Republic of Guinea harbours the largest population of the endangered western chimpanzees Pan troglodytes verus, and the conservation of this population is regarded as a regional priority. Chimpanzees occur in 3 of the 5 protected areas in Guinea but their conservation status is unknown. We conducted a chimpanzee census in 2001–2002 in the Haut Niger National Park (HNNP), the largest protected area in the country. We counted nests along a total of 103.83 km of transects in the Mafou forest, 1 of the 2 core areas of the park. We recorded a total of 823 nests, of which 38.1% were located in gallery forests, although this habitat type covers only 4.2% of the study site. Using a site-specific mean nest decay rate of 194 days, we estimated the mean density of chimpanzees in the study area at 0.87 weaned individuals/km2, the highest density recorded in any West African protected area. A survey conducted in 2008–2009 by other authors in the Mafou forest suggests that the chimpanzee population remained stable over the last 6 yr. Given the significance of the chimpanzee population of the HNNP at the national and international levels, we provide recommendations for its conservation over the long term. Our results highlight the importance of gallery forests as key habitat for chimpanzees in the savannah biome. We therefore recommend that more attention be paid to the conservation of this habitat in land management and conservation planning schemes. In particular, we recommend setting aside gallery forests as ecological corridors between nearby protected areas to maintain exchange between distant chimpanzee populations.  相似文献   

9.
The Chalkhill Blue Polyommatus coridon is a widespread butterfly of lowland calcareous grassland in southern Britain and is considered a good indicator of habitat condition. Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect. Analysis of annual butterfly monitoring data (transects) collected at 161 sites from 1981 to 2000 show a three-fold population recovery had occurred. The increases were at established sites, with no re-colonisations or range expansion detected. The 1980s population increase coincided with increases across the species range in stock and rabbit Oryctolagus cuniculus grazing, as well as greater protection and management of sites through protected areas and nature reserves. During the 1990s agri-environment schemes were thought to be the main conservation and policy mechanism driving the favourable conservation status of P. coridon, by facilitating appropriate habitat restoration and management. Weather played a part in the species recovery, with warm, but wet summers associated with increases in abundance. The research provides strong evidence of an important conservation success with the UK Biodiversity Action Plan, with implications for other specialist biodiversity.  相似文献   

10.
Notopterygium incisum Ting ex H. T. Chang is a rare and endangered traditional Chinese medicinal plant. In this research, we built a comprehensive habitat suitability (CHS) model to analyze the potential suitable habitat distribution of this species in the present and future in China. First, using nine different algorithms, we built an ensemble model to explore the possible impacts of climate change on the habitat distribution of this species. Then, based on this model, we built a CHS model to further identify the distribution characteristics of N. incisum‐suitable habitats in three time periods (current, 2050s, and 2070s) while considering the effects of soil and vegetation conditions. The results indicated that the current suitable habitat for N. incisum covers approximately 83.76 × 103 km2, and these locations were concentrated in the Tibet Autonomous Region, Gansu Province, Qinghai Province, and Sichuan Province. In the future, the areas of suitable habitat for N. incisum would significantly decrease and would be 69.53 × 103 km2 and 60.21 × 103 km2 in the 2050s and 2070s, respectively. However, the area of marginally suitable habitat would remain relatively stable. This study provides a more reliable and comprehensive method for modelling the current and future distributions of N. incisum, and it provides valuable insights for highlighting priority areas for medicinal plant conservation and resource utilization.  相似文献   

11.
To prioritise conservation actions and management strategies for threatened forest deer species at the Atlantic forest, we aimed to identify and describe the most suitable habitat areas for forest deer species and to indicate conservation measures for state agents and local communities. We adopt an approach based on ecological niche modelling, key variable thresholds and spatial analyses. In addition, we associated our approach with a human influence index, an invasive species dataset of occurrences, protected area cover and IUCN category. We indicate 2 % (484 km2) of the Atlantic forest cover as conservation priority areas (CPAs). Of these, 56.8 % are outside protected areas, 20.7 % are inside IUCN categories i, ii and iii protected areas, 19.9 % are inside IUCN categories iv, v, and vi protected areas, and 2.6 % are inside indigenous areas. Also, we indicate the most relevant protected areas for deer conservation in the Atlantic forest. The CPAs were classified into more human-influenced areas (MHIA) and less human-influenced areas (LHIA), and we identified 21 significant (greater than120 km2) continuous CPAs outside protected areas. We highlight actions in several perspectives of human influence, governance levels and law protection that would rationalise the use of funds and human resources.  相似文献   

12.
Abstract The general model of regeneration dynamics in Nothofagus forests of southern South America could have value in community ecology if predictive relationships between disturbance history, functional traits and site attributes could be identified. Examined here is the proposal that on favourable sites shade‐intolerant Nothofagus are likely not to survive in competition with shade‐tolerant, broad‐leaved evergreen taxa of temperate rain forests, and persistence, thus, is dependent on periodic coarse‐scale disturbance. Comparison of stand dynamics of three old‐growth Nothofagus forests at different elevations in the southern Andes, Chile where deciduous Nothofagus alpina dominates the upper canopy, and examination of the life history trade‐offs of this variation were made. Stem density of all stems ≥5.0 cm d.b.h. was 233–303 stems per hectare, and basal area was 123.9–171.0 m2ha?1. Maximum lifespan of N. alpina was found to be greater than ca 640 years, exceeding all previously reported ages for this species in the region. Forests had a stable canopy composition for this long‐term, but some appeared to lack effective regeneration of N. alpina in recent years. Regeneration of N. alpina was generally greater in disturbed stands and higher elevation than in undisturbed stands and at lower elevation. Recruitment emerged to be strongly affected by competitive over‐ and understorey associates. There was a gradient of increasing dependence of N. alpina on disturbance towards the more productive end of the environment gradients, and hence less dependence of N. alpina on disturbance for its regeneration towards higher elevation. The study confirms that changes in forest composition may be explained by processes occurring in accordance with the predictions of the existing model of Nothofagus regeneration dynamics, providing stronger evidence specifically directed at mid‐tolerant N. alpina, and by factoring out regeneration dynamics on favourable sites. Thus, for N. alpina, trait differences probably contribute to the competitive advantage over its associates in productive habitats, and may be linked to small‐to‐intermediate‐sized disturbances which inevitably occur as older trees die, enabling N. alpina to persist in forests and therefore maintain species coexistence for the long‐term.  相似文献   

13.
The effect of glaciation on the levels and patterns of genetic variation has been well studied in the Northern Hemisphere. However, although glaciation has undoubtedly shaped the genetic structure of plants in the Southern Hemisphere, fewer studies have characterized the effect, and almost none of them using microsatellites. Particularly, complex patterns of genetic structure might be expected in areas such as the Andes, where both latitudinal and altitudinal glacial advance and retreat have molded modern plant communities. We therefore studied the population genetics of three closely related, hybridizing species of Nothofagus (Nobliqua, N. alpina, and N. glauca, all of subgenus Lophozonia; Nothofagaceae) from Chile. To estimate population genetic parameters and infer the influence of the last ice age on the spatial and genetic distribution of these species, we examined and analyzed genetic variability at seven polymorphic microsatellite DNA loci in 640 individuals from 40 populations covering most of the ranges of these species in Chile. Populations showed no significant inbreeding and exhibited relatively high levels of genetic diversity (HE = 0.502–0.662) and slight, but significant, genetic structure (RST = 8.7–16.0%). However, in N. obliqua, the small amount of genetic structure was spatially organized into three well‐defined latitudinal groups. Our data may also suggest some introgression of N. alpina genes into N. obliqua in the northern populations. These results allowed us to reconstruct the influence of the last ice age on the genetic structure of these species, suggesting several centers of genetic diversity for N. obliqua and N. alpina, in agreement with the multiple refugia hypothesis.  相似文献   

14.
Identifying habitat suitability and potential corridors are important tools for biodiversity conservation in the face of climate change. We modeled habitat suitability and simulated possible corridors for movement and gene flow among the Asiatic black bear (Ursus thibetanus) population in the Northern Highlands of Pakistan (NHP). Results indicated that the areas of 13,923 km2 and 21,931 km2 suitable for the Asiatic black bear under current and future scenarios respectively. Under the future scenario, we found an area of 12,657 km2 (57.21%) as increase in suitable habitat (ISHf) and 4649 km2 (33.39%) area as a decrease in current suitable habitat (DSHc). Our model predicted that about >65% (9274 km2) of the current suitable habitat as a climate refugia which is projected from the center to southeast east and northwest of the NHP primarily in the Khyber Pakhtunkhwa (KPK) and Pakistan Administered Kashmir (PAK). The attitudinal range of refugia was projected from 688 m to 4483 m with >56% at the elevations between 2001 m to 3000 m. A very small portion of suitable habitats (current suitable habitat = 2.75%, future suitable habitat = 5.11%) were projected under the protected areas. Maps connecting suitable habitats identified different regions delineated as important for the dispersal of Asiatic black bears, which mainly distributed in the PAK and KPK. Our results help informs conservation strategies and management plans for mitigating the impacts of climate change on Asiatic black bears in the NHP.  相似文献   

15.
The successful implementation of habitat conservation measures demands regular and spatially explicit monitoring and reporting on conservation status at a range of scales, based on indicators of both habitat range and condition (structure and functions required for long-term maintenance). Such is the case with the Natura 2000 protected areas in Europe. Focusing on the cork oak (Quercus suber) forests of one such area, the Serra de Monchique in southern Portugal, we test the complementarity and joint effectiveness of airborne multispectral and laser scanning (lidar) in providing robust indicators of conservation status. Principal forest types and other land covers are mapped to an accuracy of up to 70% (11 land cover classes) and 81% (5 classes) by fusing the two remote sensing datasets, results that are superior to using either one alone. Using previously tested relationships between lidar height metrics, forest vegetation structure and species diversity, we develop a map predicting areas of high (22% of area), medium (25%) and low (53%) condition. We recommend the further development and testing of remotely sensed range and condition indicators of conservation status for their application in important forested sites across Europe and beyond.  相似文献   

16.
While there is agreement that both habitat quality and habitat network characteristics (such as patch size and isolation) contribute to the occupancy of patches by any given species, the relative importance of these factors is under debate. This issue is of fundamental ecological importance, and moreover of special concern for conservation biologists aiming at preserving endangered species. Against this background we investigated patch occupancy in the violet copper Lycaena helle, one of the rarest butterfly species in Central Europe, in the Westerwald area (Rhineland-Palatinate, Western Germany). Occupied (n = 102) differed from vacant (n = 128) patches in altitude, size, connectivity, availability of wind shelter, in the abundance of the larval host-plant, in the abundance of a grass species indicating favorable habitat conditions and in the abundance of nitrophilous plants. Overall, patch occupancy was primarily determined by patch size, connectivity and the abundance of the larval host plant, while all other parameters of habitat quality were of subordinate importance. Therefore, our findings suggest that even for extremely sedentary species such as L. helle habitat networks are decisive and—next to the preservation of habitat quality—need to be an integral part of any conservation management for this species.  相似文献   

17.
Guaiacum sanctum and Guaiacum coulteri are long‐lived Mesoamerican timber tree species heavily exploited throughout their range and considered to be at risk of extinction. Both species are included on the IUCN Red List and on CITES Appendix II, but there has been no formal assessment of the conservation status of either species. We used ecological niche modeling and rapid assessments of local density and population size structure to provide such evaluations. For the year 2000, we estimated geographic range sizes for G. sanctum and G. coulteri of 95,422 and 130,973 km2, respectively. The main core remaining habitat for G. sanctum occurs in Campeche State (Yucatan Peninsula), where populations exhibit high adult abundance and profuse regeneration. Several areas along the Mexican Pacific coast remain with suitable habitat for G. coulteri. Guaiacum coulteri is at greater risk as only 1.3 percent of its current habitat is protected, which contrasts with the 13.2 percent of current habitat protected for G. sanctum. We projected that available habitat for G. sanctum and G. coulteri will decline by a further 30–50 percent by 2020 if estimated habitat loss rates continue. We suggest that under the IUCN criteria, the conservation status of G. sanctum and G. coulteri should be updated to near threatened and vulnerable, respectively. Additionally, we conclude that the amount of protected habitat needs to be increased to safeguard both species. Our study provides a quantitative basis for updating the conservation status of both species and illustrates an assessment framework that could be applied to other threatened tree species.  相似文献   

18.
Land-use change is a major driver of the global biodiversity crisis, mainly via the fragmentation and loss of natural habitat. Although land-use changes will accelerate to meet humankind's growing demand for agricultural products, conservation planning rarely considers future land uses and how they may affect the connectivity of ecological networks. Here, we integrate land-use models with landscape fragmentation and connectivity analyses, to assess the effects of past and future land-use changes on the connectivity of protected area networks for a highly dynamic region in southeast Spain. Our results show a continued geographical polarisation of land use, with agricultural intensification and urban development in the coastal areas, and the abandonment of traditional land use in the mountains (e.g., 1100 km2 of natural vegetation are projected to be lost in coastal areas whereas 32 km2 of natural vegetation would recover in interior areas from 1991 to 2015). As a result, coastal protected areas will experience increasing isolation. The connectivity analyses reveal that the two protected area networks in place in the study area, the European “Natura 2000” and the Andalusian “RENPA” networks, include many landscape connectors. However, we identify two areas that currently lack protection but contain several important patches for maintaining the region's habitat connectivity: the northwestern and the southwestern slopes of the Sierra Cabrera and Bédar protected area. Our results highlight the importance of considering future land-use trajectories in conservation planning to maintain connectivity at the regional scale, and to improve the resilience of conservation networks.  相似文献   

19.
Four Special Areas of Conservation (SACs) have been designated in the Republic of Ireland for Twaite shad, Alosa fallax (Lacépède), based on recent historical information on spawning activity—the estuarine reaches of the Rivers Munster Blackwater, Suir, Barrow–Nore and Slaney. The spawning status of some of these populations is considered to have declined substantially in recent years, and no known spawning areas of Allis shad, Alosa alosa (L.), are known for Ireland. Data are presented confirming the presence of both Allis shad and Twaite shad in all four SACs. The majority of the material has come as by-catch from estuarine commercial salmon netsmen. Angling is the principal source of material from the R. Barrow. Examination of scale and gonad material of Allis shad indicates some degree of readiness for spawning as well as spawning having taken place. Gonadosomatic index (GSI) data from the R. Barrow for Twaite shad in the May spawning period (2000–2002) had mean GSIs of 13.7–15% with maxima in the range of 21–28%. GSI values of 18% and 22% have been recorded in the July period for individual Allis shad from the upper estuaries of the R. Slaney and R. Suir, respectively, with both fish displaying gonad maturity stage V or VI (after Pina, 2000). Low GSI values have been recorded from other Allis shad in the June–July period displaying gonad condition varying from stage III (immature) to stage VIII (spent). These findings point to a possibility that Allis shad do engage in spawning activity, whether mono-specifically or with Twaite shad. The possibility of the latter is supported by gill raker count data presented. These show clearly defined value ranges for Twaite and for Allis as well as a series of fish with intermediate counts. The apparently low population levels of Twaite shad within the SACs identify a need to examine what measures might be undertaken to ensure the favourable conservation status of this species. Submitted for oral presentation to Fish Diadromy in Europe conference, 27.1.2005. Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot Fish and diadromy in Europe (ecology, management, conservation)  相似文献   

20.
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