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1.
Current approaches in terrestrial biodiversity conservation focus predominantly on plants and vertebrates. While these groups account for less than 4% of the estimated global species richness, it is commonly argued that especially the species richness in higher plants is a suitable indicator of overall biodiversity. We tested this assumption, investigating species richness and equitability patterns in three highly species-rich insect families and their links with the vegetation and other environmental factors. Vegetation surveys were combined with pitfall and light trapping to establish the α-diversity of ground beetles, geometrid moths and arctiid moths on 48 plots at varying altitudes between Beijing and the Inner Mongolian Plateau. Soil pH and nutrient status were also recorded. The α-diversity patterns in the three insect families were non-congruent, and links with phytodiversity were weak. The spatial α-diversity patterns in each of the three insect families were significantly correlated with the species density of individual plant families. These links varied between the three insect taxa and were mostly negative in moths. Furthermore, geometrid moth diversity decreased with increasing elevation and decreasing soil pH. Strongly diverging α-diversity patterns across different insect taxa illustrate that it is impossible to find a simple surrogate representing cross-taxon diversity for these highly diverse groups. Furthermore, phytodiversity and vegetation composition appear to play a limited role in governing insect diversity patterns. These results underline the significant risk that current plant-focused approaches in terrestrial biodiversity conservation are inadequate in addressing the conservation needs of the vast majority of species on earth.  相似文献   

2.
In an agricultural landscape in eastern Austria eight terrestrial organism groups were investigated as potential biodiversity indicators. We present a cross-taxon congruence assessment obtained at the landscape scale using two groups of plants (bryophytes and vascular plants), five groups of invertebrates (gastropods, spiders, orthopterans, carabid beetles and ants) and one vertebrate taxon (birds). We tested four different approaches: correlated species counts, surrogate measures of the overall species richness that was assessed, a multi-taxa (or shopping basket) approach and a simple complementarity algorithm. With few exceptions, pairwise correlations between taxa, correlations between one taxon and the species richness of the remaining groups, and correlations between a combination of the richness of two taxa and the remaining species richness were highly positive. Complementarity-derived priority sets of sampling sites using one taxon as a surrogate for the pooled species richness of all other taxa captured significantly more species than selecting areas randomly. As an essential first step in selecting useful biodiversity indicators, we demonstrate that species richness of vascular plants and birds showed the highest correlations with the overall species richness. In a multi-taxa approach and in complementarity site selection, each of the eight investigated taxa had the capability to capture a high percentage of the overall species richness.  相似文献   

3.
Fertilization of secondary successional communities generally increases biomass but reduces diversity; its impact on primary successional communities is less well understood. Following applications of a balanced fertilizer to naturally established vegetation on slate quarry waste, effects on tree growth, ground flora species and foliar invertebrates were monitored over two years. Fertilization increased tree growth, with stem basal area increasing by 130% over two growing seasons compared with a 50% increase in unfertilized trees. Several dominant ground flora species increased in cover as a result of fertilization. In contrast, cover of bryophytes was not increased. Fertilization favoured plant species associated with drier habitats, but disadvantaged less-competitive ruderal species. Tree foliar invertebrates were less abundant on the trees on slate waste than on trees in established woodland. Fertilization made tree leaves more palatable by increasing nitrogen and reducing soluble polyphenol concentrations, and increased the abundance of sap-sucking invertebrates, without changing foliar invertebrate diversity. Overall, fertilizing this primary successional site was beneficial for biodiversity; it increased abundance of dominant plant species and foliar invertebrate herbivores, yet few taxa were adversely affected during this period. Increases in tree biomass and invertebrate abundance are likely to favour the establishment of other taxa. Where the biodiversity conservation interest is principally in closed-canopy vegetation, applying fertilizer is a cheap, comparatively non-intrusive and effective way to increase biodiversity on denuded sites. However, plant species characteristic of open and infertile habitats (particularly bryophytes) and their obligate herbivorous invertebrates are likely to decrease in abundance.  相似文献   

4.
Regional-scale biodiversity indicators provide important criteria for the selection of protected areas in conservation, but their application is often hindered by a lack of taxonomic knowledge. Moreover, different indicators include different types of information, sometimes leading to divergent conservation priorities. Madagascar tops the world list of biodiversity hotspots and much conservation effort has been directed toward its threatened plants and vertebrates. In contrast, its highly diverse freshwater invertebrate fauna has received comparatively little conservation attention. We conducted an inventory of Malagasy adephagan water beetles (Coleoptera, Dytiscidae, Noteridae, Gyrinidae, Haliplidae) using a combined morphological and molecular approach. In total, 2043 beetles from 153 sites were sequenced for cytochrome oxidase subunit I (cox1), and species delimitation was carried out using the coalescent-based GMYC model. Phylogenetic relationships of the resulting entities were established using cox1 combined with partial 16S rRNA and 28S rRNA sequences. Ten national parks were assessed for their species richness, phylogenetic diversity (PD) and endemism. We were particularly interested in the contribution of endemic species to PD. Congruence between molecular and taxonomic identifications was high (91%), with 69% of sampled species endemic to Madagascar. Interestingly, we found that PD at a site was negatively correlated to the proportion of endemic species, most likely because endemics are the result of recent radiations with relatively little branch-length contribution to the measure of PD. This suggests that ranking sites for conservation priority based solely on PD potentially disfavor endemic species by underrating areas where the evolutionary process is most active.  相似文献   

5.
Conservation biology is mainly interested in prioritizing sites on the basis of their high biodiversity. Although species richness is a commonly used criterion, it does not take other crucial aspects of identifying conservation priority sites into account, such as rarity or taxonomic distinctness. Additionally, management efforts are usually focused on the conservation of a small number of species, mainly vertebrates. However, the biodiversity patterns of these faunal groups and the main factors which determine them cannot be generalized to other faunal groups (e.g. aquatic invertebrates). Therefore, the objectives of the present study are: (1) to compare the response of 11 biodiversity metrics in order to know which ones are redundant, (2) to identify key environmental factors for biodiversity, and (3) to find out whether sites with high biodiversity values also have a good habitat condition and high protection status. The study was done at assemblage level (crustaceans and insects) in 91 wetlands in the NE Iberian Peninsula. Regression tree models were used to identify the key factors influencing biodiversity, including water, wetland and landscape characteristics as explanatory variables. Generalized Linear models were used to establish the relationship between biodiversity metrics and protection status and habitat condition. The results obtained by the two sampled seasons were compared. Conductivity was the main factor influencing biodiversity metrics. Positive significant relationships were found between some biodiversity metrics and wetland habitat condition, whereas there were none for protection status, indicating the inadequacy of conservation policies to protect wetland aquatic invertebrate biodiversity.  相似文献   

6.
Landscape classifications are increasingly being used in conservation planning and biodiversity management, although there is a dearth of studies actually showing concordant patterns between such classifications and biodiversity. We studied the utility of tributary and stream type classifications in accounting for the variability of invertebrate biodiversity in a boreal drainage system. We found that only weak, although significant, differences existed between the studied three tributaries and four stream types in macroinvertebrate assemblage structure, species distributions, and taxonomic richness. Further, the classification strengths, calculated as mean within-group-similarity minus mean between-group-similarity of assemblage structure, were rather low, suggesting that the a priori physical classifications did not effectively describe variability in macroinvertebrate assemblage structure. The low classification strengths likely resulted from the facts that: (i) most stream macroinvertebrate taxa show individualistic responses to environmental gradients; (ii) many taxa occur either across all stream types; or (iii) only sporadically in a given stream type; and (iv) only a few species show high fidelity to a given stream type. However, the significance of the differences in macroinvertebrate assemblage structure and taxonomic richness, as well as a bunch of effective indicator species for different stream types, suggest that such classifications could be used as a preliminary scheme for the conservation planning of running waters. This reasoning is also supported by the evidence from other studies that have found stream size and the distance to upstream lakes to shape considerably the biodiversity of various groups of stream organisms, although no single organism group is likely to show a perfect match with any classification scheme.  相似文献   

7.
We analyze the impact of grazing on dung beetle diversity at the Barranca de Metztitlán Biosphere Reserve, a xeric ecosystem in central Mexico with a long history of use by humans. We compared the community structure, as well as the alpha and beta diversity between two cover conditions (open and closed vegetation) that represent the impact of grazing within a habitat, and between habitat types (submountainous and crassicaule scrublands). From 576 samples we collected 75,605 dung beetles belonging to 20 taxa. While mean species richness and diversity were different between habitat types, cumulative species richness was not. The effects of grazing on vegetation structure influenced the cumulative species richness and diversity of dung beetles in the submountainous scrubland, where grazing has created land mosaics of a grassland matrix with scrubland patches. This was not the case in the crassicaule scrubland where the impact of grazing is not as evident. Beta diversity significantly responds to the effects of grazing on habitat conditions. We discuss the ecological factors that may promote these responses by landscape diversity components. We also identify the species that could act as useful indicators to monitor the effect of land management on biodiversity. Our results indicate cattle farming maintains a diversified land mosaic, and these areas support more diverse dung beetle ensembles than homogeneous areas of closed, shrubby vegetation cover. Thus, controlled grazing activity could certainly favour the conservation of dung beetle biodiversity and improve ecosystem functioning by maintaining dung decomposition rates.  相似文献   

8.
Invasive plants are, simply by occupying a large amount of space in invaded habitats, expected to impose a significant impact on the native vegetation and their associated food webs. However, little is known about the impact of invasive plants both on native vegetation and on different invertebrate feeding guilds at the habitat level. Yet, studies addressing multiple trophic levels, e.g. plant species, herbivores, predators and detrivores, are likely to yield additional insight into how and under which conditions invasive weeds alter ecosystem structures and processes. We set out to assess whether plant species richness and invertebrate assemblages in European riparian habitats invaded by exotic knotweeds (Fallopia spp.) differed from those found in native grassland- or bush-dominated riparian habitats, which are both potentially threatened by knotweed invasion. Our findings suggest that riparian habitats invaded by knotweeds support lower numbers of plant species and lower overall abundance and morphospecies richness of invertebrates, compared to native grassland-dominated and bush-dominated habitats. Total invertebrate abundance and morphospecies richness in Fallopia-invaded riparian habitats were correlated with native plant species richness, suggesting that there is a link between the replacement of native plant species by exotic Fallopia species and the reduction in overall invertebrate abundance and morphospecies richness. Moreover, biomass of invertebrates sampled in grassland and bush-dominated habitats was almost twice as high as that in Fallopia-invaded habitats. Large-scale invasion by exotic Fallopia species is therefore likely to seriously affect biodiversity and reduce the quality of riparian ecosystems for amphibians, reptiles, birds and mammals whose diets are largely composed of arthropods.  相似文献   

9.
Understanding the cultural variation in public preference for marine species is a necessary pre-requisite if conservation objectives are to include societal preferences in addition to scientific considerations. We report the results of a contingent study undertaken at three case-study sites: Azores islands (Portugal), Gulf of Gdansk (Poland) and Isles of Scilly (UK). The study considered species richness of five specific marine taxa (mammals, birds, fish, invertebrates and algae) as proxies of marine biodiversity and the aim of analysis was to estimate from a multi-site perspective public’s willingness to pay (WTP) to avoid increased levels of species loss (reduction of species richness) for different marine taxa. Results, based on 1502 face-to-face interviews, showed that income, education and environmental awareness of the respondents were significant predictors of WTP for marine species conservation. Results also indicated that respondents in each of the European locations had different preferences for marine taxa. In the Azores, although mammals and fish were valued highly, small differences occurred in the WTP among different taxa. Respondents in the Isles of Scilly put a relatively low value on fish while algae and marine mammals were highly valued. In Gdansk, respondents defined a clear order of preference for marine mammals > fish > birds > invertebrates and algae. These findings suggested that cultural differences may be important drivers of valuation and undermines the commonly held premise that charismatic/likeable taxa consistently have a disproportionately strong influence on WTP for biodiversity conservation. We conclude that conservation policy must take account of cultural diversity alongside biological diversity.  相似文献   

10.
Surrogate taxa as indicators for biodiversity are widely used in conservation biology and ecology. However, available studies on the congruence of species diversity patterns in different taxa yielded inconsistent results, and correlations between taxa were few. To conserve or restore biodiversity in agricultural landscapes, knowledge on the response of different taxa to management regimes is crucial. In the present study we evaluated the congruence of diversity and similarity patterns among three insect taxa, i.e., bees, grasshoppers, and aculeate wasps, in a mosaic landscape in the Swiss Alps comprising extensively used grassland under different management regimes. In addition, we studied the influence of land use on the diversity and species composition of the three taxa. While species numbers were not significantly correlated between any pair of taxa, community similarities were positively correlated between bees and grasshoppers. The number of red-listed species was not correlated with the total number of species in bees and in grasshoppers. None of the investigated taxa reflected the species numbers or community similarities of the other taxa well enough to qualify as a general indicator for biodiversity. Remarkably, land use clearly influenced species composition, while its effect on species numbers was not significant. All management regimes of the grassland in the study area contribute substantially to the overall diversity of the three insect taxa. Conserving the variety of agricultural land uses will be the most promising step towards the conservation of biodiversity in the study area.  相似文献   

11.
Saproxylic organisms are among the most threatened species in Europe and constitute a major conservation problem because they depend on the most important forestry product - dead wood. Diversity of fungal and bryophyte communities occurring on dead beech trees was analyzed in five European countries (Slovenia, Hungary, The Netherlands, Belgium and Denmark) considering tree level species richness (TLSR), country level species richness (CLSR), frequency distributions of species, occurrence of threatened species and relations between TLSR and decay stage, tree size and countries. Altogether 1009 trees were inventoried in 19 beech dominated forest reserves.The number of fungi in the full dataset was approximately three times larger (456 versus 161 species) and the proportion of low frequent species was higher than among bryophytes. The species richness of bryophytes and fungi was significantly different among countries considering both TLSR and CLSR. In addition the diversity patterns deviated considerably between the two groups of organisms. Slovenian sites appeared to be biodiversity hotspots for bryophytes characterized by high TLSR and CLSR and a high fraction of threatened species. Hungarian sites had somewhat lower bryophyte diversity, while the Atlantic region had deteriorated assemblages. Fungal species richness was very high in Denmark, but the Hungarian and Slovenian sites were richer in threatened and low frequency species. Tree size was better able to explain variation in TLSR in both organism groups than decay stage. TLSR was found to vary significantly between countries but the difference was most considerable in the case of bryophytes.The diversity patterns of both organism groups along the investigated geographical gradient appear to be influenced by both climatic and management related factors (forest history, dead wood availability and continuity, habitat fragmentation). There is no doubt that an increase in the abundance of dead wood in European beech forests will benefit diversity of saproxylic fungi and bryophytes, especially if a continuous presence of large diameter logs are secured within individual stands.  相似文献   

12.
Ponds are among the most diverse and yet threatened components of freshwater biodiversity. The conservation of ponds would greatly benefit from the identification of surrogate taxa in preliminary assessments aimed at detecting ponds of potentially high biodiversity value. Here, we used predictive co-correspondence analysis (Co-CA) to quantify the strength of plant species composition and plant community types in predicting multivariate patterns in water beetle assemblages, based on data from 54 farmland ponds in Ireland. The predictive accuracy of a number of environmental variables as well as that of plant diversity (species richness and evenness) was calculated using predictive canonical correspondence analysis (CCA-PLS). The study ponds supported over 30% of the Irish water beetle fauna (76 species), with five species having some form of IUCN Red List Status in Ireland, as well as 67 wetland plant species, including a nationally rare one. Co-CA showed that plant species composition had a positive predictive accuracy, which was significantly higher compared to that of data at the plant community type level. Although environmental variables showed a higher predictive capacity compared to that of plant species composition, the difference was not significant. Explanatory CCA analyses showed that plants and beetles both responded to the same subset of environmental conditions, which explained approximately 18% of the variation in both plant and beetle species composition. Regional differences as well as permanency, substratum, and grazing intensity affected the composition of both plant and beetle assemblages. These findings have important implications in conservation planning. First, wetland plants can be effectively used as a surrogate taxon in the identification of conservation-priority ponds. Second, conservation strategies aimed at maintaining and enhancing pond biodiversity should be based on considerations on plant species composition.  相似文献   

13.
Knowledge of how roads affect forest biodiversity can be improved by measuring the responses of indicator species to complex environmental gradients caused by these infrastructures. We studied litter invertebrate species responses to road edges in laurel and pine forests in Tenerife, Canary Islands. We sampled invertebrates from litter and assessed the environmental variation related to road proximity. We also assessed the effect of relevant environmental predictors on a diverse array of potential indicator species. We applied canonical ordination and non-parametric regression (Lowess) to classify invertebrate species responses to roads and their associated gradients. Three types of responses to road edge proximity were defined for the most common invertebrate taxa: edge-preferring or edge specialists, interior-preferring or edge-avoiders, and edge-indifferent or neutral species. Those species appearing most frequently and with higher population density between 1 and 20 m from the edge (commonly peaking at 10 m from the road) were categorized as edge-preferring. We classified taxa attaining peak population densities at or beyond 60 m from the edge (and most commonly 100 m) as interior species. Edge-neutral species were those without an evident pattern of stabilization in abundance along the gradient and with peaks in abundance at varying distance intervals. These edge litter communities contain a high native and endemic diversity but also a significant density of alien fauna. The specific patterns of penetration of road edge effects on invertebrate species should be seen as having a pervasive and cumulative impact considering the exceptionally large number of roads in these forests and the high population densities of alien invertebrates. Future management plans for forest conservation on the Canary Islands should include the highly altered but valuable litter communities along road edges.  相似文献   

14.
Human-modified tropical landscapes under semi-natural or agro-ecosystems often harbor biodiversity of significant conservation value. In the Western Ghats of India, these ecosystems also provide connectivity between protected areas and other remnant forests. We investigated the conservation value of these landscapes and agro-ecosystems using results from 35 studies covering 14 taxonomic groups. Large, conspicuous taxonomic groups and tree-covered land-use types have received much focus in this area of research in the Western Ghats. We computed a response ratio defined as the log ratio of species richness in human land use to species richness in forest control site from 17 studies. In a meta-analysis, we investigated variation of this ratio across studies with respect to three variables: taxonomic group, the land-use type sampled and the extent of forest cover within the study landscape. Higher forest cover within the landscape emerged as a major positive influence on biodiversity in human-modified landscapes for vertebrates and vegetation while no patterns emerged for invertebrates. Our results suggest that loss of remnant forest patches from these landscapes is likely to reduce biodiversity within agro-ecosystems and exacerbate overall biodiversity loss across the Western Ghats. Conservation of these remnant forest patches through protection and restoration of habitat and connectivity to larger forest patches needs to be prioritized. In the densely populated Western Ghats, this can only be achieved by building partnerships with local land owners and stakeholders through innovative land-use policy and incentive schemes for conservation.  相似文献   

15.
National conservation planning should operate with measures of biodiversity similar to those applied globally in order to harmonize national and international conservation strategies. Here we suggest quantitative measures which enable two criteria of the global biodiversity hotspots to be applied on a national level for 74 large countries, and show how these measures can be applied to map national biodiversity hotspots. The plant endemism criteria of global hotspots are captured by quantitative measures of endemism, which are approximately scale-independent and can be corrected to account for a country’s environmental conditions and conservation priorities. The flexible land use criteria for national biodiversity hotspots are defined from percentage of natural vegetation remaining in the global hotspots. The minimum-area-required approach is applied to define the borders of national biodiversity hotspots using data on vascular plants species richness. We show how national biodiversity hotspots can be mapped from the species-energy relationship for vascular plants using climate, topographical and land use data when spatial pattern of species richness is not known. This methodology to map national biodiversity hotspots from abiotic factors is applied to Russia as a case study. Three Russian biodiversity hotspots, North Caucasus, South Siberia and Far East were identified. The resulting hotspot maps cover national-scale environmental gradients across Russia and although they are also identified by Russian experts their actual geographical locations were hitherto unspecified. The large-scale national hotspots, identified for Russia, can be used for further fine scale and more detailed conservation planning.  相似文献   

16.
The invasive signal crayfish (Pacifastacus leniusculus) may undergo ontogenetic diet shifts with increasing size, but the consequences of crayfish size-structure changes for aquatic food webs are little known. We evaluated size-dependent impacts of signal crayfish on a littoral marsh food web using in-situ enclosures in a northern Japanese marsh. During the 60-day experiment, large crayfish (<30 mm orbital carapace length) rapidly eliminated submerged macrophytes through mechanical destruction while the comparable impacts of small crayfish (>30 mm) appeared after more time had passed. Benthic algal biomass was reduced in the presence of large crayfish but was affected little by small crayfish, suggesting that large crayfish were significant bioturbators. On the other hand, total invertebrate biomass was reduced while total invertebrate density was enhanced in the presence of both crayfish size classes. Potential crayfish impacts on invertebrates are: (1) predation on large vulnerable taxa such as Trichoptera and predatory invertebrates, (2) mechanical destruction of macrophytes, thereby reducing microhabitats for invertebrates, (3) heightened emigration of invertebrates in response to bioturbation and/or (4) predation or competition release on small invertebrates as a result of crayfish reducing their predators/competitors. Invertebrate taxa richness was nearly halved in the presence of large crayfish, probably reflecting reductions of rare taxa. Overall, functional roles of signal crayfish as omnivores and ecosystem engineers remained similar during the ontogenetic stage but the magnitude and rate of crayfish impacts intensified with increasing crayfish size. Thus, removal of large invasive crayfish alone may reduce detrimental impacts on aquatic biodiversity.  相似文献   

17.
Southeast Asia experiences one of the highest rates of deforestation in the tropics due to agricultural expansion, logging, habitat fragmentation and urbanization, which are expected to result in species declines and extinctions. In particular, growing global demands for food, biofuel and other commodities are driving the rapid expansion of oil palm and paper-and-pulp industries at the expense of lowland dipterocarp forests, further jeopardizing Southeast Asian forest biotas. We synthesize recent findings on the effects of land-use changes on plants, invertebrates, vertebrates and ecosystem functioning/services in Southeast Asia. We find that species richness and abundance/density of forest-dependent taxa generally declined in disturbed compared to mature forests. Species with restricted ranges and those with habitat and foraging specialization were particularly vulnerable. Forest loss also disrupted vital ecosystem services (e.g. crop pollination). Long-term studies are needed to understand biotic sustainability in regenerating and degraded forests, particularly in the context of the synergistic or additive effects of multiple agents of biodiversity loss (e.g. invasive species and climate change). The preservation of large tracts of mature forests should remain the principal conservation strategy in the tropics. In addition, reforestation and reintroductions of native species, as well as improved connectivity among forest patches could enhance the conservation value of forest remnants in human-dominated landscapes.  相似文献   

18.
Information about the relative biodiversity value of different waterbody types is a vital pre-requisite for many strategic conservation goals. In practice, however, exceptionally few inter-waterbody comparisons have been made. The current study compared river, stream, ditch and pond biodiversity within an 80 km2 area of lowland British countryside. The results showed that although all waterbody types contributed to the diversity of macrophytes and macroinvertebrates in the region, they differed in relative value. Individual river sites were rich but relatively uniform in their species composition. Individual ponds varied considerably in species richness, with the richest sites supporting similar numbers of taxa to the best river sections, but the poorest sites amongst the most impoverished for all waterbody types. At a regional level, however, ponds contributed most to biodiversity, supporting considerably more species, more unique species and more scarce species than other waterbody types. Streams typically supported fewer species and fewer unique species at local and regional level than either ponds or rivers. Ditches (most of which were seasonal) were the least species-rich habitat, but supported uncommon species, including temporary water invertebrates not recorded in other waterbody types. Multivariate analysis indicated that permanence, depth, flow and altitude were the main environmental variables explaining invertebrate and plant assemblage composition. The findings, as a whole, suggest that ponds and other small waterbodies can contribute significantly to regional biodiversity. This contrasts markedly with their relative status in national monitoring and protection strategies, where small waterbodies are largely ignored.  相似文献   

19.
Despite their high diversity and importance for humankind, invertebrates are often neglected in biodiversity conservation policies. We identify seven impediments to their effective protection: (1) invertebrates and their ecological services are mostly unknown to the general public (the public dilemma); (2) policymakers and stakeholders are mostly unaware of invertebrate conservation problems (the political dilemma); (3) basic science on invertebrates is scarce and underfunded (the scientific dilemma); (4) most species are undescribed (the Linnean shortfall); (5) the distribution of described species is mostly unknown (the Wallacean shortfall); (6) the abundance of species and their changes in space and time are unknown (the Prestonian shortfall); (7) species ways of life and sensitivities to habitat change are largely unknown (the Hutchinsonian shortfall).Numerous recent developments in taxonomy, inventorying, monitoring, data compilation, statistical analysis and science communication facilitate overcoming these impediments in both policy and practice. We suggest as possible solutions for the public dilemma: better public information and marketing. For the political dilemma: red-listing, legal priority listing and inclusion in environmental impact assessment studies. For the scientific dilemma: parataxonomy, citizen science programs and biodiversity informatics. For the Linnean shortfall: biodiversity surrogacy, increased support for taxonomy and advances in taxonomic publications. For the Wallacean shortfall: funding of inventories, compilation of data in public repositories and species distribution modeling. For the Prestonian shortfall: standardized protocols for inventorying and monitoring, widespread use of analogous protocols and increased support for natural history collections. For the Hutchinsonian shortfall: identifying good indicator taxa and studying extinction rates by indirect evidence.  相似文献   

20.
Grasslands are often characterized by small-scale spatial heterogeneity due to the juxtaposition of grass tufts and bare ground. Although the mechanisms generating plant spatial patterns have been widely studied, few studies concentrated on the consequences of these patterns on belowground macrofauna. Our objective was to analyze the impact of grass tuft (Brachiaria bryzantha cv. marandu) spatial distribution on soil macrofauna diversity in Amazonian pastures, at a small scale (less than 9 m2). Soil macrofauna was sampled among B. bryzantha tufts, which showed a variable spatial distribution ranging from dense to loose vegetation cover. The vegetation configuration explained 69% of the variation in total soil macrofauna density and 68% of the variation in total species richness. Soil macrofauna was mainly found in the upper 10 cm of soil and biodiversity decreased with increasing distances to the nearest grass tuft and increased with increasing vegetation cover. The size of the largest grass tuft and the micro-landscape connectivity also had a significant effect on biodiversity. The density and species richness of the three principal soil ecological engineers (earthworms, ants and termites) showed the best correlations with vegetation configuration. In addition, soil temperature significantly decreased near the plants, while soil water content was not influenced by the grass tufts. We conclude that soil macrofauna diversity is low in pastures except close to the grass tufts, which can thus be considered as biodiversity hotspots. The spatial arrangement of B. bryzantha tussocks influences soil macrofauna biodiversity by modifying soil properties in their vicinity. The possible mechanisms by which these plants could affect soil macrofauna are discussed.  相似文献   

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