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1.
In this study, we test for the key bioclimatic variables that significantly explain the current distribution of plant species richness in a southern African ecosystem as a preamble to predicting plant species richness under a changed climate. We used 54,000 records of georeferenced plant species data to calculate species richness and spatially interpolated climate data to derive nineteen bioclimatic variables. Next, we determined the key bioclimatic variables explaining variation in species richness across Zimbabwe using regression analysis. Our results show that two bioclimatic variables, that is, precipitation of the warmest quarter (R2 = 0.92, P < 0.001) and temperature of the warmest month (R2 = 0.67, P < 0.001) significantly explain variation in plant species richness. In addition, results of bioclimatic modelling using future climate change projections show a reduction in the current bio‐climatically suitable area that supports high plant species richness. However, in high‐altitude areas, plant richness is less sensitive to climate change while low‐altitude areas show high sensitivity. Our results have important implications to biodiversity conservation in areas sensitive to climate change; for example, high‐altitude areas are likely to continue being biodiversity hotspots, as such future conservation efforts should be concentrated in these areas.  相似文献   

2.
Invasive alien plants (IAP) are a threat to biodiversity worldwide. Understanding and anticipating invasions allow for more efficient management. In this regard, predicting potential invasion risks by IAPs is essential to support conservation planning into areas of high conservation value (AHCV) such as sites exhibiting exceptional botanical richness, assemblage of rare, and threatened and/or endemic plant species. Here, we identified AHCV in Georgia, a country showing high plant richness, and assessed the susceptibility of these areas to colonization by IAPs under present and future climatic conditions. We used actual protected areas and areas of high plant endemism (identified using occurrences of 114 Georgian endemic plant species) as proxies for AHCV. Then, we assessed present and future potential distribution of 27 IAPs using species distribution models under four climate change scenarios and stacked single‐species potential distribution into a consensus map representing IAPs richness. We evaluated present and future invasion risks in AHCV using IAPs richness as a metric of susceptibility. We show that the actual protected areas cover only 9.4% of the areas of high plant endemism in Georgia. IAPs are presently located at lower elevations around the large urban centers and in western Georgia. We predict a shift of IAPs toward eastern Georgia and higher altitudes and an increased susceptibility of AHCV to IAPs under future climate change. Our study provides a good baseline for decision makers and stakeholders on where and how resources should be invested in the most efficient way to protect Georgia's high plant richness from IAPs.  相似文献   

3.
Aim  Identifying areas of high species richness is an important goal of conservation biogeography. In this study we compared alternative methods for generating climate-based estimates of spatial patterns of butterfly and mammal species richness.
Location  Egypt.
Methods  Data on the occurrence of butterflies and mammals in Egypt were taken from an electronic database compiled from museum records and the literature. Using M axent , species distribution models were built with these data and with variables describing climate and habitat. Species richness predictions were made by summing distribution models for individual species and by modelling observed species richness directly using the same environmental variables.
Results  Estimates of species richness from both methods correlated positively with each other and with observed species richness. Protected areas had higher species richness (both predicted and actual) than unprotected areas.
Main conclusions  Our results suggest that climate-based models of species richness could provide a rapid method for selecting potential areas for protection and thus have important implications for biodiversity conservation.  相似文献   

4.
The distribution of tropical plant and animal diversity is still poorly documented, especially at spatial resolutions of practical use for conservation. In the present study, we evaluated the level to which geographical incomplete data availability of species occurrence affects the perception of biodiversity patterns (species richness and endemism) among pteridophytes in Bolivia. We used a data base of Bolivian pteridophytes (27,501 records), divided it into three time periods (1900–70, up to 1990 and up to 2006), and created grid-files at 15'-resolution for species richness and endemism. For each of these biodiversity properties we estimated the species richness (Chao 2) and the index of sampling completeness (C index) per grid, and then all these variables at both species richness and endemism were correlated. Patterns of richness were fairly consistent along all periods; the richest areas were placed along the humid-montane forest, even though they were strongly influenced by collecting intensity. Endemism had a lower degree of correlation with collecting intensity, but varied much more strongly through time than species richness. According to the C index, which gives the ratio between estimated (by Chao 2) and recorded values of species richness and endemism, both biodiversity properties tended to be undersampled in the richest grid cells. Inter-temporal correlations showed sharper differences of correlations for endemism than species richness. Consequently, already in 1970, botanists had a correct idea of the spatial distribution of pteridophyte richness in Bolivia (even though the magnitude was grossly underestimated). In contrast, patterns of endemism, which are of high conservation importance, may not even today be reliably known.  相似文献   

5.
Floristic surveys were performed in 17 traditional cocoa forest gardens under different management regimes in the humid forest area of southern Cameroon, to assess the impact of intensification on plant biodiversity. This impact was evaluated by analyzing species richness, vegetation structure, carbon sequestration and above ground biomass. We hypothesize that: (a) plant (tree and herbs) species richness is negatively correlated to management intensity and (b) vegetational density predictably change with management intensity. Our results show that management as practiced in traditional cocoa forest gardens in southern Cameroon following a gradient of intensification from extensive cocoa forest gardens with high floristic diversity to intensive ones strongly impacts plant diversity, plant biomass and to some extend carbon storage with possible negative consequences on biodiversity. Great differences in species richness, species composition, and, for trees, diameter at breast height and basal area were evident among the five types of traditional cocoa forest garden systems investigated. In terms of plant species richness, we found a decreasing gradient of plant species numbers from extensive forest gardens to intensive ones. This study also highlights the importance of the Management Index for quantifying differences in the management; this index could be used to standardize certification procedures and assess conservation progress and success. Our findings support the idea that traditional cocoa forest gardens can help to protect many forest species, sustains smallholder production and offer more scope for conservation of biodiversity, at both species-level and landscape-level. Moreover, diverse traditional cocoa forest gardens may help in regulating pests and diseases and allow for efficient adaptation to changing socioeconomic conditions.  相似文献   

6.
Roadless areas are important for biodiversity maintenance and nature conservation but remain politically controversial due to conflicting interests of conservation and development. In this study, we applied a recently developed index of roadless volume (RV) across 67 counties of Alabama, USA as a case study to examine the relationships between roadless areas and local species richness. Our results indicated that with the increase of RV across counties, both the number of total fish and exotic fish species increased, but the relationship was not significant for endemic fish species. The number of both herpetofaunal and plant species also increased with the increasing RV. For all included species, there was a significant positive correlation between species richness and RV values. The number of endangered species decreased with the increase of RV per-capita. Wildfire occurrences increased with the increase of RV. Preserving roadless areas is an important component of biodiversity conservation.  相似文献   

7.
While reforestation is gaining momentum to moderate climate change via carbon sequestration, there is also an opportunity to use tree planting to confront declining global biodiversity. Where tree species vary in support of diversity, selecting appropriate species for planting could increase conservation effectiveness. We used a common garden experiment in Borneo using 24 native tree species to examine how variation among tree species in their support of beetle diversity is predicted by plant traits associated with “acquisitive” and “conservative” resource acquisition strategies. We evaluate three hypotheses: (1) beetle communities show fidelity to host identity as indicated by variation in abundance and diversity among tree species, (2) the leaf economic spectrum partially explains this variation as shown by beetle preferences for plant species that are predicted by plant traits, and (3) a small number of selected tree species can capture higher beetle species richness than a random tree species community. We found high variation among tree species in supporting three highly intercorrelated metrics of beetle communities: abundance, richness, and Shannon diversity. Variation in support of beetle communities was predicted by plant traits and varied by plant functional groups; within the dipterocarp family, high beetle diversity was predicted by conservative traits such as high wood density and slow growth, and in non‐dipterocarps by the acquisitive traits of high foliar K and rapid growth. Using species accumulation curves and extrapolation to twice the original sample size, we show that 48 tree species were not enough to reach asymptote levels of beetle richness. Nevertheless, species accumulation curves of the six tree species with the highest richness had steeper slopes and supported 33% higher richness than a random community of tree species. Reforestation projects concerned about conservation can benefit by identifying tree species with a disproportional capacity to support biodiversity based on plant traits.  相似文献   

8.
A significant fraction of higher plants in China are threatened due to dramatic landscape transformation and increasing climate change. However, the conservation effectiveness of threatened higher plants (THPs) and their response to climate change are still underexplored to date. Based on the latest list of THPs in China, we obtained 102 593 occurrence records with latitude and longitude for 3858 THPs. By integrating the distribution patterns of three biodiversity indexes (i.e., species richness, species complementarity, and weighted endemism) and 10 plant categories, we identified hotspots for THPs and calculated the conservation effectiveness of nature reserves. We then selected 1959 THPs to project the shift of species richness and range sizes under climate change (representative concentration pathway [RCP] 2.6 and RCP 8.5). In total, 16 hotspot areas covering 7.38% of Chinese land area and containing 91.73% of THPs were identified. Current nature reserves protected 35.05% of hotspots, 73.07% of all THPs, and 56.64% of narrow-ranged species. By the 2070s, the species richness of THPs were predicted to decrease in Southeast and Central China, and 42.42% (RCP 2.6) and 51.40% (RCP 8.5) of the 1959 THPs would confront habitat contraction. Future conservation efforts should focus on the conservation gaps and carry out targeted conservation for THPs with narrow distribution range. In order to cope with climate change, the hotspots with relatively low species loss can serve as important areas to contain current species diversity and the areas with high species gain offer opportunities for ex-situ conservation of THPs.  相似文献   

9.
The biodiversity hotspot concept was defined by Myers in 1988 to determine priority areas for conservation. They have high endemism levels and have lost more than 70% of their original vegetated area. To date, there is little information on arthropod diversity in these zones. This work focuses on the biodiversity of the Phytoseiidae (Acari), one of the best known among the order Mesostigmata, in these threatened areas. These mites are usually predators and they are worldwide spread. Geographic distribution of phytoseiids in 27 biodiversity hostspots was assessed from data of the last world catalogue published in 2004. One thousand two hundred and thirty species are reported from at least one hotspot (62% of the total species number) and 604 species (30% of the total species number) are endemic to the 27 hotspots considered. The number of reports/publication in hotspot areas (2.6) is higher than in non-hotspot zones (1.5). Hotspots areas could be thus considered as a great reservoir of the Phytoseiidae diversity, just as they are for vertebrates and plants. Correlations between plant, vertebrate, mite diversity and endemism, as well as congruence rates between endemism levels of these three organisms suggest that the biodiversity patterns of plants and vertebrates mirror well those of the Phytoseiidae (both for endemicity and species richness). More intense conservation efforts in biodiversity hotspots would thus be assumed to affect plant and vertebrate biodiversity, as already known, but also arthropod biodiversity, as it was assumed. These results further support thus the importance of these zones in biodiversity conservation, even for organisms like mites, very small and poorly studied in this regards. More data on arthropods are, however, required to confirm these preliminary observations.  相似文献   

10.
The South American corridor of seasonally dry vegetation (SACSV) includes different types of physiognomies forming a continuous corridor with high biodiversity and endemism; however, little attention has been paid to the conservation of the SACSV. As this is an area with great diversity, cataloguing all the species is challenging. Thus, we suggest the use of Leguminosae species (trees and shrubs) as bioindicators of the different types of vegetation present in the area and to identify priority areas for conservation of the SACSV, since the family is highly represented in this vegetation. The study area was divided into 358 grid cells with recorded specimens. For each grid cell, species richness, taxonomic diversity, number of species restricted to one type of vegetation, and threatened and indicator species of phytogeographic domain were calculated. To determine the phytogeographic domains and indicator species, analysis of similarity, cluster and indicator species (ISA) were performed. The results show that 43% of the grid cells (154) have high biological importance for conservation (high taxonomic diversity, species richness and number of restricted species), all of which lie outside of protected areas. We identified 72 indicator species for seven floristic units, which, in general, include areas of the same phytogeographic domain, supporting the existing classification systems. We suggest that for effective conservation of biodiversity present in the SACSV, it is necessary to establish protected areas throughout the SACSV.  相似文献   

11.
Aim We evaluated Odonata distribution data and predicted the compositional resemblance based on niche‐based species distribution models to analyse the following questions: (1) How is estimated species richness distributed, and how can it be preserved under the actual network of conservation units (a gap analysis approach)? (2) How is the estimated odonate beta diversity distributed, and is there a better distribution of conservation units (a priority setting approach)? (3) Is the probability of being under protection a function of the potential species range size? and (4) Will the current conservation network proposals protect odonate taxa? Location Central Brazil in a core Cerrado area. Methods We generated odonate species distribution predictions based on MaxEnt and maps derived from estimated species richness, beta diversity and gap analysis for all species predicted to occur in the study area. Then, we compared these maps with current conservation units, land‐use patterns and proposals for the establishment of conservation units. Results Raw odonate species records provided limited utility for setting conservation priorities without the use of niche‐based models. However, area under the receiver operating curve (AUC) values were characterized by substantial variation that was related to the number of records. No current conservation units overlapped the areas with higher predicted richness and beta diversity, and in general, conservation units were not preserving restricted/rare species. There was a direct linear correlation between species range size and the proportion of its range protected in the current network of conservation units. Finally, we identified three areas with high odonate beta diversity where conservationist actions should be implemented. Main conclusions Current conservation units and future suggested areas do not overlap regions with high conservation values for odonates. Conservation units protect species at random, and the level of protection has a direct relationship with species range size; thus, wide‐range species are expected to be more protected than restricted or threatened species.  相似文献   

12.
Evaluations of species richness patterns have been performed at diverse scales, and biodiversity hotspots, especially endemism hotspots, have received much attention in conservation biology. We estimated the distributions of endemic bird species based on a 12-yr avian inventory project in Taiwan, identified biodiversity hotspots of endemism on a regional scale based on predictions from the ensemble forecasting framework and frequency histogram approach, and assessed the efficiency of protected areas. The results indicated that the predicted endemism hotspots were mostly located in mid- and high-elevation areas along the Central Mountain Range of Taiwan. An observed endemism hotspot was defined as one in which at least five of Taiwan's 17 endemic bird species were present. This criterion was used because the 5% of the sampled grid squares that were the richest in endemic bird species all had 5 endemic bird species or more. Seventy to seventy-one percent of the observed biodiversity hotspots matched the predicted biodiversity hotspots. This outcome was obtained whether the richness biodiversity in a grid square was based on summed predicted probability or summed predicted richness. The majority of the protected areas for these Taiwanese endemic bird species were national parks, protecting 24.1% of the predicted hotspot areas, whereas nature reserves and wildlife refuges protected less than 7%. Most of the predicted endemism hotspots were not adequately protected. We conclude that the ensemble forecasting framework and the frequency histogram approach are useful for selecting critical habitats and biodiversity hotspots for endemic species and for appraising the efficiency of the protection status provided by governments.  相似文献   

13.
大别山地区植物资源丰富,区系组成复杂且起源古老,为连接华东、华北和华中三大植物区系的纽带,也是我国重要的生物多样性保护和水源涵养生态功能区。采用样方法,在大别山南坡的多枝尖、庵基坪和麒麟沟3个地区,沿着不同海拔高度选取了具有代表性的森林植物群落进行研究,从不同植物群落类型和层次的物种多样性、均匀度和丰富度及其与海拔因子的关系等方面,对大别山南坡的森林植物群落物种多样性进行综合分析。结果表明:1. 共记录有植物108科270属449种,划分为20个森林植物群落类型;2. 森林植物群落各层次物种丰富度表现为草本>乔木>灌木;Shannon-Wiener多样性指数和Simpson多样性指数呈现出乔木>灌木>草本;Pielou均匀度指数变化较为复杂;3. 森林植物群落各层次的物种丰富度随海拔升高而下降;Shannon-Wiener指数和Simpson指数也表现为随着海拔升高而下降,但草本层在1400m之后有上升的趋势。Pielou指数在乔木层中表现为随着海拔的升高而下降,在草本层中表现为先下降后出现上升,在灌木层中则随着海拔的升高而上升,但其波动更为剧烈。本研究对大别山南坡森林植被大范围的采样观测研究,能够全面的展现大别山南坡森林植物的种类分布、空间组成等整体概况及其与海拔因子的关系,能为以后大别山南坡生物多样性的保护提供较为全面真实的数据,从而为大别山地区生物多样性的保护和可持续利用提供理论依据和实践意义。  相似文献   

14.
何荣晓  雷金睿  杨帆 《广西植物》2021,41(3):351-361
植物多样性监测是开展物种保护与植被景观规划的重要基础,对实施生物多样性的优先区域保护具有重要意义.该文以海口市主城区为例,利用Landsat 8遥感数据与样方实测数据分析了植被指数与植物多样性指数之间的相关性,根据相关性分析结果构建植物多样性遥感监测数学模型,并筛选出最优模型用于监测研究区植物多样性的空间分布状况.结果...  相似文献   

15.
In the face of accelerating biodiversity loss it is more important than ever to identify important areas of biodiversity and target limited resources for conservation. We developed a method to identify areas of important plant diversity using known species’ distributions and evaluations of the species importance. We collated distribution records of vascular plants and developed a scoring method of spatial prioritisation to assign conservation value to the island of Ireland at the hectad scale (10 km × 10 km) and at the tetrad scale (2 km × 2 km) for two counties where sufficient data were available. Each plant species was assigned a species conservation value based on both its conservation status and distribution in Ireland. For each cell, the species conservation values within the cell were summed, thereby differentiating between areas of high and low conservation value across the landscape. Areas with high conservation value represent the most important areas for plant conservation.The protected area cover and the number of species present in these important areas were also examined by first defining threshold values using two different criteria. Species representation was high in the important areas; the identified important areas of plant diversity maintained high representation of species of conservation concern and achieved high species representation overall, requiring a low number of sites (<8%) to do so. The coincidence of protected areas and important areas for plant diversity was found to be low and while some important areas of plant diversity might benefit from the general protection afforded by these areas, our research highlights the need for conservation outside of protected areas.  相似文献   

16.
Italian north Tyrrhenian regions harbour pure or nearly pure cork oak woodlands towards the NE limit of the species range and the highest proportion of the habitat on mainland Italy, but their distribution, biodiversity and conservation status are still poorly known. Focusing on the key region of Tuscany, we analysed distribution and plant species richness of these forests based on literature and original field data. The habitat covers about 5.730?ha and is strongly fragmented for natural and non-natural reasons, underscoring its relict character. Out of the 420 plant taxa recorded, 19 were listed in IUCN categories at the national or regional level. Taxonomic singularity was especially high at the genus rank. Three neighbouring areas with different soil conditions and forest structure were compared based on field surveys, sample plots and linear transects from dense stands to shrub and herbaceous communities of small openings. The Versegge site showed the highest species richness at the area-scale and the mean diversity at the plot scale, representing a key biotope for the conservation of the habitat. However, the geographic–floristic covariation between the three sites suggested that a network of small areas would be more effective than a single, large area to protect the most significant components of the local cork oak flora. The Lattaia and Terzo areas may play an important role as corridor sites between the four SCIs of the Rete Natura 2000 network including cork oak communities on the Tuscan mainland. Species richness was higher in the stands with lower cork oak basal area, and there was a significant increase in species number along transects reaching openings caused by traditional human activities. A minor anthropic disturbance of traditional type may help to preserve the fine-scale habitat heterogeneity and the biodiversity of the whole ecosystem.  相似文献   

17.
Hotspots of biodiversity are important areas in facilitating an understanding of species richness and its maintenance. Herbivores can increase plant richness by reducing dominant plant species thus providing space for subdominant species. As small mammals are abundant in the Succulent Karoo and therefore might affect plant richness by means of herbivory, we tested if this mechanism might exist in the Succulent Karoo in southern Africa, a biodiversity hotspot due to its extraordinary plant richness. At ten ecologically different study sites we measured plant and small mammal richness and diversity and determined 11 abiotic factors including soil composition, altitude and rainfall. We found positive correlations between plant richness and the number of small mammal species. A general linear model revealed that the number of small mammal species was more important than abiotic factors in explaining variation in plant richness. To test whether small mammals might directly influence plant richness, we studied the influence of the bush-Karoo rat Otomys unisulcatus, a central place forager, on the plant community. The immediate surroundings of occupied O. unisulcatus nests showed significantly higher plant richness than control areas. We conclude that small mammals can have a positive effect on plant richness in the Succulent Karoo. While experimental data are needed to support these correlative results, the results of our study indicate that areas of high small mammal richness should be included in conservation programs of the Succulent Karoo.  相似文献   

18.
Knowledge of spatial patterns of biological diversity is fundamental for ecological and biogeographical analyses and for priority setting in nature conservation, particularly in West Africa where the existing high biodiversity is increasingly threatened by human activities. The maximum entropy approach was used to model the geographic distribution of 3,393 vascular plant species at a spatial resolution of 0.0833°. Species richness decreases along temperature and precipitation gradients with high species numbers in the south and lower numbers towards the north of the transect. All centres of plant species diversity are confined to humid areas in concordance with the high positive correlation between species richness and rainfall which appears to be the most important delimiter for the distribution ranges of many species in the area. The effectiveness of the existing protected areas at regional and national levels is investigated based on the proportion of species covered. Considering the whole study area, 95% of all species are covered by protected areas according to their distribution ranges. However, the proportion of species covered is considerably lower for some countries such as Benin and Togo. Our results could provide guidance for essential land use management interventions to decision‐makers and conservationists in the region.  相似文献   

19.
《Ecological Indicators》2008,8(5):664-671
A critical issue in conservation biology is the establishment of a strong relationship between species richness and a surrogate index. Such a relationship could provide the basis for the establishment of cost effective and easy to monitor methods for measuring biodiversity, providing an alternative for the prioritization of sites for conservation. We found that richness of species of conservation interest could reliably be predicted from the richness of higher order taxa, such as genus and family, in amphibians, reptiles, birds and mammals. Furthermore, the networks of reserve sites selected based upon the richness of genera or families were as effective in including species diversity, as the ones selected based upon species richness.  相似文献   

20.
Can species richness and rarity be predicted from space? If satellite‐derived vegetation indices can provide us with accurate predictions of richness and rarity in an area, they can serve as an excellent tool in diversity and conservation research, especially in inaccessible areas. The increasing availability of high‐resolution satellite images is enabling us to study this question more carefully. We sampled plant richness and rarity in 34 quadrats (1000 m2) along an elevation gradient between 300 and 2200 m focusing on Mount Hermon as a case study. We then used 10 Landsat, Aster, and QuickBird satellite images ranging over several seasons, going up to very high resolutions, to examine the relationship between plant richness, rarity, and vegetation indices calculated from the images. We used the normalized difference vegetation index (NDVI), one of the most commonly used vegetation indexes, which is strongly correlated to primary production both globally and locally (in more seasonal and in drier and/or colder environments that have wide ranges of NDVI values). All images showed a positive significant correlation between NDVI and both plant species richness and percentage tree cover (with R2 as high as 0.87 between NDVI and total plant richness and 0.89 for annual plant richness). The high resolution images enabled us to examine spatial heterogeneity in NDVI within our quadrats. Plant richness was significantly correlated with the standard deviation of NDVI values (but not with their coefficient of variation) within quadrats and between images. Contrary to richness, relative range size rarity was negatively correlated with NDVI in all images, this result being significant in most cases. Thus, given that they are validated by fieldwork, satellite‐derived indices can shed light on richness and even rarity patterns in mountains, many of which are important biodiversity centres.  相似文献   

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