共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
An effective portfolio of protected areas should, all else being equal, give rise to positive relationships between the amount
of protected land in a region and the numbers of species present. Tests of this prediction are, however, extremely scarce,
and most do not control for the potentially confounding effects of environmental factors that influence broad geographic trends
in biodiversity. Here, we document the form of the relationship between species richness and coverage by protected areas using
the British avifauna as a case study. We contrast relationships that arise for breeding and wintering assemblages, considering
both all species collectively and threatened species only. We use spatially explicit multiple regression analyses that take
into account environmental factors previously shown to exert a marked influence on avian species richness in Britain (temperature
and altitude). Avian species richness and the amount of protected land are consistently positively correlated with each other,
and the slopes of these relationships do not differ between assemblages (breeding/wintering and all species/threatened species).
Explanatory power is, however, very weak which may be indicative of the ability of conservation measures in the wider landscape
to maintain avian species richness, reducing any distinctive influence of protected areas.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
4.
N. M. Korovchinsky 《Hydrobiologia》2000,434(1-3):41-54
The composition of the pelagic cladoceran species assemblages in some large, well-studied, lakes of Europe, Asia and Africa is reviewed based on original and literature data. In general, pelagic cladocerans are taxonomically less well studied than some littoral groups. Only the limnetic members of the family Sididae and some Daphnia have recently been revised, whereas knowledge of species diversity of other Daphniidae (including moinas) and Bosminidae is missing. Future detailed taxonomic studies may lead to considerable changes in understanding of limnetic zooplankton composition. 相似文献
5.
Aim The method used to generate hypotheses about species distributions, in addition to spatial scale, may affect the biodiversity patterns that are then observed. We compared the performance of range maps and MaxEnt species distribution models at different spatial resolutions by examining the degree of similarity between predicted species richness and composition against observed values from well‐surveyed cells (WSCs). Location Mexico. Methods We estimated amphibian richness distributions at five spatial resolutions (from 0.083° to 2°) by overlaying 370 individual range maps or MaxEnt predictions, comparing the similarity of the spatial patterns and correlating predicted values with the observed values for WSCs. Additionally, we looked at species composition and assessed commission and omission errors associated with each method. Results MaxEnt predictions reveal greater geographic differences in richness between species rich and species poor regions than the range maps did at the five resolutions assessed. Correlations between species richness values estimated by either of the two procedures and the observed values from the WSCs increased with decreasing resolution. The slopes of the regressions between the predicted and observed values indicate that MaxEnt overpredicts observed species richness at all of the resolutions used, while range maps underpredict them, except at the finest resolution. Prediction errors did not vary significantly between methods at any resolution and tended to decrease with decreasing resolution. The accuracy of both procedures was clearly different when commission and omission errors were examined separately. Main conclusions Despite the congruent increase in the geographic richness patterns obtained from both procedures as resolution decreases, the maps created with these methods cannot be used interchangeably because of notable differences in the species compositions they report. 相似文献
6.
Persistence and vulnerability: Retaining biodiversity in the landscape and in protected areas 总被引:1,自引:0,他引:1
An objective of biodiversity conservation activities is to minimize the exposure of biodiversity features to threatening processes
and to ensure, as far as possible, that biodiversity persists in the landscape. We discuss how issues of vulnerability and
persistence can and should be addressed at all stages of the conservation planning and implementation process. Procedures
for estimating the likelihood of persistence and for measuring degrees of vulnerability at different spatial and temporal
scales using subjective assessments, rules of thumb and analytical and simulation models are reviewed. The application of
information on vulnerability and persistence to conservation planning and management is discussed under the headings of natural
dynamics, replication of protection, levels of representation, source and sink population structures, refuges and critical
resources, reserve design, habitat fragmentation and levels of management. 相似文献
7.
Jeffrey R. Dunk William J. Zielinski Hartwell H. Welsh Jr 《Diversity & distributions》2006,12(4):434-442
The Klamath‐Siskiyou forests of northern California and southern Oregon are recognized as an area of globally outstanding biological distinctiveness. When evaluated at a national or global level, this region is often, necessarily, considered to be uniformly diverse. Due to large variation in biotic and abiotic variables throughout this region, however, it is unlikely that biological diversity is uniformly distributed. Furthermore, land management decisions nearly always occur at spatial scales smaller than this entire region. Therefore, we used field data from a random sampling design to map the distribution of local and regional richness of terrestrial molluscs and salamanders within northern California's portion of the Klamath‐Siskiyou region. We also evaluated the protection afforded by reserves established for varying reasons (e.g. for inspiration and recreation for people vs. species conservation) to hotspots of species richness and species representation of these taxa. No existing reserves were created with these taxa in mind, yet it was assumed that reserves established largely around considerations for the northern spotted owl (Strix occidentalis caurina) would afford adequate protection for many lesser‐known species. Species of terrestrial molluscs and salamanders share two general features: (1) they have extremely low vagility, and (2) they are often associated with moist, cool microclimates. Existing reserves disproportionately included areas of hotspots of species richness for both taxa, when hotspots included the richest c. 25% of the area, whereas non‐reserved lands contained greater than expected areas with lower species richness. However, when a more strict definition of hotspot was used (i.e. the richest c.10% of areas), local hotspots for both taxa were not disproportionately found in reserves. Reserves set aside largely for human aesthetics and recreation and those set aside for biodiversity both contributed to the protection of areas with high (greatest 25%) species richness. Existing biodiversity reserves represented 68% of mollusc species and 73% of salamander species, corresponding to the 99th and 93rd percentiles, respectively, of species representation achieved by simulating a random distribution of the same total area of reservation. Cumulatively, however, reserves set aside for inspiration and biodiversity represented 83% of mollusc species and 91% of salamander species. The existing reserves provide conservation value for terrestrial molluscs and salamanders. This reserve network, however, should not be considered optimal for either taxa. 相似文献
8.
The relationship between plant diversity and animal diversity on a broadscale and its mechanisms are uncertain. In this study, we explored this relationship and its possible mechanisms using data from 186 nature reserves across China on species richness of vascular plants and terrestrial vertebrates, and climatic and topographical variables. We found significant positive correlations between species richness in almost all taxa of vascular plants and terrestrial vertebrates. Multiple regression analyses indicated that plant richness was a significant predictor of richness patterns for terrestrial vertebrates (except birds), suggesting that a causal association may exist between plant diversity and vertebrate diversity in China. The mechanisms for the relationships between species richness of plants and animals are probably dependent on vertebrate groups. For mammals (endothermic vertebrates), this relationship probably represents the integrated effects of plants on animals through trophic links (i.e. providing foods) and non-trophic interactions (i.e. supplying habitats), whereas for amphibians and reptiles (ectothermic vertebrates), this may be a result of the non-trophic links, such as the effects of plants on the resources that amphibians and reptiles require. 相似文献
9.
Aim Cross‐system comparisons of species richness of benthic macrofauna and environmental factors were made of estuaries and adjacent sea areas in order to reveal possible regulating factors of estuarine biodiversity. Location Denmark. Methods Annual species abundance and biomass data from four years, from unvegetated soft sea/estuary floors were used from 26 grids, of which 15 were situated in estuaries. Bottom water data for oxygen concentration, salinity, and temperature were obtained from stations in or close to, the grids. Data on nutrient loading, water residence time and morphology were obtained for whole estuaries. Species richness from the grids, standardized to the same sample size, were related to environmental variables using linear regression. Results Species richness was unrelated to oxygen deficiency and productivity, but positively related to salinity. However, an equally high degree of explanation (R2 ~ 0.70) was obtained using a model where richness was positively related to saltwater flux, which was computed from estuary volume and residence time and corrected for freshwater flux. The relationship was present for the dominating groups with pelagic dispersal, Annelida and Mollusca, but not for Crustacea, where recruitment is mainly by benthic pathways. Saltwater flux was strongly positively correlated with salinity, illustrating the high importance of flux from adjacent sea areas for water renewal in Danish estuaries. Similarity of species composition was greater for sites within than between saltwater current pathways, and the increases of richness with saltwater flux and salinity in the estuaries was largely due to marine species occurring in the open sea areas. Conclusion Danish estuaries are largely open systems where a part of estuarine species richness is sustained by dispersal from a species pool in adjacent seas. Results are consistent with the barrier prediction of island biogeography theory, but not the island size prediction. 相似文献
10.
Species richness, species range size and ecological specialisation among African primates: geographical patterns and conservation implications 总被引:5,自引:0,他引:5
The geographical distribution of species richness and species range size of African anthropoid primates (catarrhines) is investigated and related to patterns of habitat and dietary niche breadth. Catarrhine species richness is concentrated in the equatorial regions of central and west Africa; areas that are also characterised by low average species range sizes and increased ecological specificity. Species richness declines with increasing latitude north and south of the equator, while average species range size, habitat and dietary breadth increase. Relationships between species richness, species range size and niche breadth remain once latitudinal and longitudinal effects have been removed. Among areas of lowest species richness, however, there is increased variation in terms of average species range size and niche breadth, and two trends are identified. While most such areas are occupied by a few wide-ranging generalists, others are occupied by range-restricted specialist species. That conservation efforts increasingly focus on regions of high species richness may be appropriate if these regions are also characterised by species that are more restricted in both their range size and their ecological versatility, although special consideration may be required for some areas of low species richness. 相似文献
11.
Due to the current environmental crisis, many animal species face extinction problems. Amphibian populations have been affected by this crisis. Our goal is to study amphibian species diversity in Chiapas, which has 7.6% of the endemic amphibians in Mexico and 53 protected areas. Only 58% of the protected areas have management plans or information on their resident amphibians. We aim to determine the extent of protection provided by the network of natural areas for the conservation of amphibian species in the state and to discuss the effectiveness of this protection. Therefore, we compiled a georeferenced database of 112 amphibian species in Chiapas to create each distribution model. In addition, we carried out representativeness, beta diversity, and species richness analyses. As a result, we obtained a high degree of representativeness for the records and species distribution models. However, we found a decrease in the richness of amphibians involving 20% of total species, 13% of endemics, 18% threatened according to NOM-059, and 31% threatened according to IUCN between 1800 and 2020 and 1980–2020. We also identified two biodiversity hotspots in the Sierra Madre de Chiapas and the Northern Highlands physiographic regions. Finally, based on potential distributions, we found more endemic and threatened species outside protected natural areas than inside them. Our results give a broader picture of how amphibian richness is distributed in Chiapas. This information can help to prioritize conservation efforts toward those areas rich in threatened or endemic species, such as the Northern Mountains Hotspot we identified in northern Chiapas. 相似文献
12.
We investigated the major patterns of plant rarity in sub-Saharan Africa, and looked for the most significant gaps in the reserve network of the region in terms of representing the distribution of threatened and geographically rare plants. Comparisons of the species ranges captured by the network of reserves were made against the proportion of species captured by randomly generated sets of areas and against a theoretical near minimum set of areas that represent all species once. At this scale of analysis, the network of large IUCN-coded reserves (the official ‘protected areas’) performs poorly against random and systematic selection procedures. Significant gaps in the IUCN-coded protected areas are in coastal Gabon/Cameroon, in the various tropical montane forest areas (Cameroon Highlands, Eastern Arc Mountains, Ethiopian Mountains), in lowland coastal eastern Africa, and in the South African Cape. Some of these gaps, for example in the Eastern Arc and eastern African coastal regions, are covered on the ground by a network of Forest Reserves under the management of national Forestry Authorities. The networks of Forest Reserves in Ghana, Nigeria, Cameroon, Uganda, Kenya, Zimbabwe, Zambia and Sierra Leone also fill reservation gaps for rare African plants in these countries. Upgrading the conservation status of some key Forest Reserves, which has been gradually happening for some decades, is proposed as an efficient way to enhance the protected area network of the Afrotropical region for the conservation of rare African plant species. 相似文献
13.
Walter J. Lusigi 《Biodiversity and Conservation》1994,3(5):449-458
Largely triggered by the Bali debate, conservation literature over the last decade has seen increasing realization of man's responsibility in ensuring survival of the world's protected areas. In African terms, there has been an overwhelming number of pilot projects which have the people label. Whereas this trend has been ecouraging, the overall conservation picture has not been very bright as the wildlife resources have continued to dwindle under surmounting human pressure. The problem does not seem to be awareness of the necessity for protected areas any more but rather whether it is feasible under the present prevailing circumstances. 相似文献
14.
With many species predicted to respond to a changing climate by shifting their distribution to climatically suitable areas, the effectiveness of static protected areas (PAs) is in question. The Madagascan PA network area has quadrupled over the past 15 years, and, although conservation planning techniques were employed to prioritise suitable areas for protection during this process, climate change impacts were not considered. We make use of species distribution models for 750 Madagascan vertebrate species to assess the potential impacts of climate change on (1) species richness across Madagascar, (2) species gain, loss and turnover in Madagascar's PAs and (3) PA network representativeness. Results indicate that Madagascar is predicted to experience substantial shifts in species richness, with most PAs predicted to experience high rates of species turnover. Provided there are no barriers to species movements, the representativeness of the current PA network will remain high for the species that are predicted to survive changes in climate by 2070, suggesting that little benefit will be gained from establishing new PAs. However, this rests on the assumption of mobility through areas currently characterised by fragmentation and anthropogenic activity, something that will require considerable expansion in conservation efforts in order to achieve. 相似文献
15.
在城市用地和保护地都快速扩张的背景下, 保护地与城市之间的距离在急剧缩小, 然而这并未引起人们的足够关注。城市对保护地的负面影响具有尺度效应, 且随着距离的接近, 负面影响也将加剧, 因此保护地与城市距离的远近可成为衡量负面影响大小的重要依据。本文基于全球保护地和大城市及城市用地分布数据, 对全球、洲际、地区和国家尺度1950-2010年城市与保护地距离的变化进行分析。结果表明: (1)在4个尺度上, 保护地与城市的距离都在不断缩小。欧洲和西欧是保护地与城市距离最近的洲和地区, 而大洋洲和澳大利亚及新西兰则是距离最远的洲和地区。在面积排名前20的保护地大国中, 中国是保护地与城市平均最近距离最小的国家, 其与50万以上人口城市的平均最近距离在2010年仅为143.5 km。(2)根据城市与保护地距离的现状及其变化, 可将保护地排名前60的国家分成5类: (a)距离很近, 靠近速度慢, 如西欧国家; (b)距离近, 靠近速度适中, 如中国、美国; (c)距离较近, 靠近速度快, 如沙特阿拉伯、厄瓜多尔; (d)距离较远, 靠近速度较慢, 如巴西、加拿大、俄罗斯联邦; (e)距离远, 靠近速度较快, 如澳大利亚、非洲大多数国家。(3)全球范围内, 越来越多生物多样性较高的保护地将面临被城市影响的境地。该结果以期引起大家对全球保护地与城市距离急剧缩短现象的关注和警惕。 相似文献
16.
17.
The effect of a marine protected area on the Lamellodiscus spp. monogenean community was tested by comparing the communities of parasites of Diplodus sargus inside and outside of the area. A total of 104 D. sargus were dissected harbouring 1280 monogeneans from the genus Lamellodiscus and belonging to 11 species. No modification in the global parasite community linked with the protection of the host populations was revealed. The most abundant and less specific parasite species, Lamellodiscus elegans , however, increased its abundance in the protected area. A significant relationship was found between parasite host range and the percentage of infected hosts. A significant relationship also occurred between epidemiological and genetic distances for the parasite species found. The results are discussed in term of parasite success and specificity and the importance of taking into account parasitism in the biological conservation of hosts. 相似文献
18.
C.L. Seymour H.M. De Klerk A. Channing T.M. Crowe 《Biodiversity and Conservation》2001,10(12):2045-2076
There is an increasing need for protected areas to conserve biodiversity efficiently. The Anura of sub-equatorial Africa have received little attention, but we quantitatively analyse a database containing presence-only data for anurans of sub-equatorial Africa to determine patterns of distribution and species richness, and discuss the roles of present and past environmental conditions in shaping these patterns. We consider the distribution of areas rich in endemic, range-restricted and Red Data Book (RDB) species to identify areas of significance to conservation. The Eastern Highlands of Zimbabwe and adjacent area in Mozambique, southeastern Malawi and the northern coast of KwaZulu/Natal are particularly species rich, whereas the southwestern Cape of South Africa and northwestern Zambia exhibit high degrees of endemism. Four major biogeographical sub-regions are identified, which can be further subdivided into provinces. All statistically significant, current environmental factors together account for 52.6% of species richness. Annual maximum rainfall, soil type variation, minimum temperature and range of elevation were all positively correlated with species richness. Thus, both habitat influences and history appear to have influenced patterns of anuran richness in the region. Generally, areas of high species richness coincide with those high in range-restricted, endemic and RDB species. In South Africa, the northeastern coast and southwestern Cape are hypothesised to have been both refugia and centres of speciation. Results suggest that the current reserve system in sub-equatorial Africa is inadequate for the conservation of the full complement of anuran species in the region. 相似文献
19.
The under-financing of protected areas in the Congo Basin: so many parks and so little willingness-to-pay 总被引:1,自引:0,他引:1
Protected areas in the Congo Basin cover approximately 6% of the landscape, and several international NGOs are proposing substantial additions to the present network of parks and reserves. Yet, chronic under-funding has long precluded effective management of most parks and reserves resulting in their progressive ecological impoverishment, and the loss of biodiversity. Furthermore, not only are the indebted nations of the Congo Basin not in a position to contribute significantly to cover the recurring costs of protected area management, the growing opportunity costs of setting aside protected areas is increasing the incentives to local communities and national governments to 'illegally' exploit economically valuable resources within parks and reserves. If the global value of the biodiversity contained within the Congo Basin is considered worth preserving then donors and international NGOs must work with national governments to reach consensus on an optimal protected area network that (a) contains a representative assemblage of forest species; (b) is composed of forest blocks that are sufficiently large, intact, and likely to persist; (c) contains zones of active speciation (e.g. ecotones), and (d) can expect to receive sufficient long-term financial support to ensure effective management. Given the 'need to eat today' reality of economies in the Congo Basin, the international community must decide to shoulder most of the costs of conservation of globally important biodiversity. If donors continue to under-finance protected areas rather than make the hard choices associated with prioritizing protected area spending then most if not all protected areas within the Congo Basin will continue to exhibit reductions in the biomass of individual species, and risk the extirpation or extinction of large, slow reproducing species, and rare endemics. 相似文献
20.
Patterns of species richness hotspots and estimates of their protection are sensitive to spatial resolution 下载免费PDF全文
Alexa J. McKerrow Nathan M. Tarr Matthew J. Rubino Steven G. Williams 《Diversity & distributions》2018,24(10):1464-1477