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1.
Industrial timber plantations severely impact biodiversity in Southeast Asia. Forest fragments survive within plantations, but their conservation value in highly deforested landscapes in Southeast Asia is poorly understood. In this study, we compared bird assemblages in acacia plantations and fragmented forests in South Sumatra to evaluate each habitat’s potential conservation value. To clarify the impact of habitat change, we also analyzed the response of feeding guild composition. Five habitat types were studied: large logged forest (LLF), burnt logged forest (BLF), remnant logged forest (RLF), 4-year-old acacia plantation (AP4), and 1-year-old acacia plantation (AP1). Estimated species richness (Chao 2) was highest in LLF then AP4 and BLF, while AP1 and RLF had lower estimated species richness. Community composition was roughly divided into two groups by non-metric multidimensional scaling ordination: acacia plantation and logged forest. Sallying substrate-gleaning insectivores, such as drongos, broadbills, and some flycatchers, were restricted to LLF, whereas acacia plantation hosted many terrestrial frugivores, such as doves. Although fragmented forests in our study site lacked several common tropical forest species, these fragments provide an important habitat for some sallying and terrestrial insectivores. A network of small riparian remnant forests could be a complementary habitat for some species, while the conservation value of burnt forest might be low. In conclusion, the highly fragmented forests in plantations are suboptimal habitats for birds but are still very important, because large primary forest blocks have been nearly lost in the surrounding landscape.  相似文献   

2.
The once extensive native forests of New Zealand’s central North Island are heavily fragmented, and the scattered remnants are now surrounded by a matrix of exotic pastoral grasslands and Pinus radiata plantation forests. The importance of these exotic habitats for native biodiversity is poorly understood. This study examines the utilisation of exotic plantation forests by native beetles in a heavily modified landscape. The diversity of selected beetle taxa was compared at multiple distances across edge gradients between each of the six possible combinations of adjacent pastoral, plantation, clearfell and native forest land-use types. Estimated species richness (Michaelis–Menten) was greater in production habitats than native forest; however this was largely due to the absence of exotic species in native forest. Beetle relative abundance was highest in clearfell-harvested areas, mainly due to colonisation by open-habitat, disturbance-adapted species. More importantly, though, of all the non-native habitats sampled, beetle species composition in mature P. radiata was most similar to native forest. Understanding the influence of key environmental factors and stand level management is important for enhancing biodiversity values within the landscape. Native habitat proximity was the most significant environmental correlate of beetle community composition, highlighting the importance of retaining native remnants within plantation landscapes. The proportion of exotic beetles was consistently low in mature plantation stands, however it increased in pasture sites at increasing distances from native forest. These results suggest that exotic plantation forests may provide important alternative habitat for native forest beetles in landscapes with a low proportion of native forest cover.  相似文献   

3.
Scarab beetles (Coleoptera: Scarabaeidae) have been used to investigate the effects of environmental disturbances on forest structure and diversity. This group is recognized as sensitive to habitat perturbations and ecosystem changes. Here we examine the effects of anthropogenic impacts on Scarabaeidae composition, testing the following hypotheses: (1) Scarab beetle communities react to land use disturbances with predictable trends, (2) disturbed habitats are able to retain only a part of the Scarab beetle community of native forests or late secondary forests; (3) habitats largely differ in terms of species richness, taxonomic diversity and ecological composition, supporting exclusive and indicator species. We selected areas of native forest, agriculture, pasture for extensive livestock and secondary forests in different stages of regeneration. Our results show that the Scarabaeidae species were not indifferent to the gradient of structural changes represented by the studied areas. In fact, their patterns of habitat preference reveals communities more abundant and diverse in pristine habitats. In contrast, disturbed habitats, dominated by agricultural activities and pasture, indicated clear detrimental effects on the abundance of all forest Scarab beetle specialists. On the other hand, the generalist species, mainly associated with open environments, seemed to be favoured by the prevailing conditions induced by agricultural activities. Overall, the composition of the Scarab beetle communities is variable and sensitive to those structural gradients and, therefore, capable of responding as useful ecological indicators for assessing the extent of land use change or degradation.  相似文献   

4.
The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.  相似文献   

5.
The segregation of land-use intensity signifies an important change in land use in lac insect agroecosystem of Southwestern China. Farming conversions have led to a highly diversified landscape, with a mosaic made up of patches of land with different succession, from cultivated lands to closed forest. Our aim here is to characterize ant assemblages within this mosaic and identify key ant community metrics and species that can be used for bioindication. The habitats supported different level of ant species richness and abundance. For ants captured by pitfall trapping, the mean plot species richness in lac plantation was significantly higher than that in dry land (deforestation land-use). For ants captured by sweep netting and foliage shaking, there was significant difference among lac plantation, dry land and secondary forest occurring from afforestation of lac plantations, with lac plantation having greatest species richness. Ant species composition was different among the three land-use habitats. Seven of the fifteen most common species had statistically different abundances or occurrence within the three land-uses. Thirteen species had statistically significant different distributions among land-use habitats (among them three species were captured by sweep netting and foliage shaking). Ten species had statistically significant habitat associations determined by IndVal analysis. Among these ten species, five ant species were associated with secondary forest, two with lac plantation, and three with dry land. Lac plantation integrated with lac-production and farming is clearly an important land-use protecting ant diversity, and thus having great conservation potential. The use of ants as bio-indicators is a promising method for determining ecological responses to human land use in China.  相似文献   

6.
Traditional agro-pastoral practices are in decline over much of the Alps, resulting in the complete elimination of livestock grazing in some areas. Natural reforestation following pastoral abandonment may represent a significant threat to alpine biodiversity, especially that associated with open habitats. This study presents the first assessment of the potential effects of natural reforestation on dung beetles by exploring the relationships between the beetle community (abundance, diversity, species turnover and assemblage structure) and the vegetation stages of ecological succession following pastoral abandonment. A hierarchical sampling design was used in the montane belt of the Sessera Valley (north-western Italian Alps). Dung beetles were sampled across 16 sampling sites set in four habitat types corresponding to four different successional stages (pasture, shrub, pioneer forest and beech forest) at two altitudinal levels. The two habitats at the extremes of the ecological succession, i.e. pasture and beech forest, had the greatest effect on the structure of local dung beetle assemblages. Overall, dung beetle abundance was greater in beech forest, whereas species richness, Shannon diversity and taxonomic diversity were significantly higher in pasture, hence suggesting this latter habitat can be considered as a key conservation habitat. Forests and pastures shared a lower number of species than the other pairs of habitats (i.e. species turnover between these two habitats was the highest). The two intermediate seral stages, i.e. shrub and pioneer forest, showed low dung beetle abundance and diversity values. Local dung beetle assemblages were also dependent on season and altitude; early-arriving species were typical of pastures of high elevation, whereas late-arriving species were typical of beech forests. It is likely that grazing in the Alps will continue to decrease in the future leading to replacement of open habitats by forest. This study suggests therefore that, at least in the montane belt, reforestation may have potentially profound and negative effects on dung beetle diversity. Maintaining traditional pastoral activities appears to be the most promising approach to preserve open habitats and adjacent beech forests, resulting in the conservation of species of both habitats.  相似文献   

7.
The loss of natural habitats is one of the main drivers of biodiversity decline. Anthropogenic land uses preserving biotic and abiotic conditions of the native ecosystem are more suitable to preserve the native biodiversity. In this study, we explored changes in species richness and composition in different land uses of the southern Atlantic forest, considering three independent factors: (1) canopy (presence–absence), (2) type of vegetation (native–exotic) and (3) livestock (presence–absence). We expected a gradient of response in the richness and composition of the native forest dung beetle community, from land uses preserving canopy and native vegetation to open land uses with exotic vegetation. Dung beetles were sampled in protected native forests and four land uses, using two potential food resources: human dung and carrion. The species richness and composition of each habitat, as well as differences in composition and the influence of factors over diversity, were then analyzed. As expected, our results showed that land uses preserving canopy and native vegetation maintain the dung beetle diversity of the native forest. Moreover, while the three factors analyzed influenced dung beetle diversity, canopy cover was the main driver of dung beetle diversity loss. The main conclusion of this study is that the conservation of canopy (either native or exotic) is determinant to preserve highly diverse dung beetle communities and subsequently, the ecological functions performed by this taxon. However, the ecophysiological mechanism behind the response of dung beetles to habitat disturbance is poorly understood.  相似文献   

8.
In many regions of tropical Asia, the expansion of rubber monoculture plantations is conducted by replacement of natural forest areas and strongly affects biodiversity and movement patterns of wild species, including insects. Against this background, we conducted a study on selected insect groups (longhorn beetles, bark beetles, wild bees and hoverflies) along transects between rainforest patches, open uncultivated land and rubber plantation habitats in a region of Xishuangbanna (southern Yunnan, China), with the objectives to identify (a) movement directions and patterns of selected insect groups based on their abundances in modified Malaise traps in the different habitats, and (b) the role of remaining natural rainforest patches and rubber plantations, respectively, for insect diversity maintenance and conservation. The highest total numbers of species and individuals of bark beetles, longhorn beetles and wild bees were recorded from the natural forest edge compared to open land and rubber plantation edge. This result clearly indicates that the natural forest plays an important role in maintenance of these three insect groups. However, the highest number of hoverfly species and individuals was recorded from the open land sites, indicating the most relevant habitat type for this group of species. Overall, the lowest species and individual numbers were recorded from the rubber plantation edge, indicating the unsuitability of this habitat type for all insect groups considered. The distribution of species and individuals in the opposite trap sides along the transect indicates that longhorn beetles, bark beetles and wild bees show not only movements from the forest to the surrounding habitats, but also return back after encountering the unsuitable rubber plantation habitat. Bark beetle composition showed the relatively highest similarity between all trap sites and opposite trap sides among the insect groups considered, indicating a higher movement activity than the other groups. The four insect groups considered in this study show different movement modes between the forest, open land and rubber plantation, which are not the same for all taxa. Except for hoverflies, the natural forest was found to be the most important habitat for the maintenance of species diversity in the different land use types of the study area.  相似文献   

9.
Plantation forests have been expanding in many tropical and subtropical environments. Howerver, even when they replace less wildlife friendly land uses such as pastures and annual crops, the biodiversity levels of pristine natural habitats often have not been recovered. Here we addressed how the landscape context of plantation forests located in South-eastern Brazil affects species richness and community resilience of medium and large size mammals. The area covered by native habitat fragments surrounding plantation forests is positively related to functional richness, including the presence of species more vulnerable to extinction in fragmented landscapes. In addition, the degree of aggregation of plantation forest stands is negatively related to more vulnerable species. No primates were recorded in our seven plantation forest sites (ranging from 272 to 24,921 ha), even when they were seen in native habitat fragments adjacent to commercial tree stands. Two invasive species (Sus scrofa and Lepus capensis) were recorded in four plantation forest sites. The impoverishment of fauna in plantation forests is due to two factors. First, plantation forests generally are structurally simplified habitats when compared to highly diverse tropical forests. Secondly, the isolation from habitat fragments which act as source of individuals in the landscape precludes the establishment of individual in plantation forest. We also highlighted the management practices to improve the complexity of vegetation in commercial tree stands should be taken cautiously, insofar as reduced productivity per area entails a greater demand for land. Thus, an alternative would be intensify the management of the commercial tree stands for wood production together with the restoration of adjacent areas set aside to conservation and native habitat fragments protection.  相似文献   

10.
Land-use systems (LUS), placed in originally forested areas, represent different degrees of opportunity for species conservation. In this study, we examined the dung beetle communities in order to identify the conservation value of different LUS: primary forest, old secondary forest, young secondary forest, agroforestry, agriculture and pasture in Western Amazon. The LUS were sampled in two campaigns during the highest precipitation period and dryest period. The primary forest has a high number of total and exclusive species. Large beetles show a continuous decreasing in richness and abundance from primary forest to pastures, while small ones are not sensible to intermediate systems (secondary forest to agriculture) in terms of species richness and exhibit a increase in abundance at agroforest and agriculture when contrasted to secondary forest and pasture The beetle community composition was not sensible to secondary forest recovering time. Secondary forests and agroforestry stood out as harboring many species shared with primary forests. Cloud-point dispersion (average dissimilarity) increased from primary forest towards LUS’s submitted to more intense use. The higher sampling points similarity observed in primary forest might be the result of the relative stability of this system, given that environmental impacts might increase variability in community structure and beta diversity. Increase in beta diversity as expressed by greater dispersion of sites in multivariate space suggests that these areas are dependent on nearby species pools, possibly primary forests, and harbor a higher spatial heterogeneity in species composition. This high variability can overestimate the importance of occasional species, thus biasing the actual value of alternative LUS for biodiversity conservation.  相似文献   

11.
Human land-use changes are particularly extensive in tropical regions, representing one of the greatest threats to terrestrial biodiversity and a key research topic in conservation. However, studies considering the effects of different types of anthropogenic disturbance on the functional dimension of biodiversity in human-modified landscapes are rare. Here, we obtained data through an extensive review of peer-reviewed articles and compared 30 Neotropical bat assemblages in well-preserved primary forest and four different human-disturbed habitats in terms of their functional and taxonomic diversity. We found that disturbed habitats that are structurally less similar to primary forest (pasture, cropland, and early-stage secondary forest) were characterized by a lower functional and taxonomic diversity, as well as community-level functional uniqueness. These habitats generally retained fewer species that perform different ecological functions compared to higher-quality landscape matrices, such as agroforestry. According to functional trait composition, different bat ensembles respond differently to landscape change, negatively affecting mainly gleaning insectivorous bats in pasture, narrow-range species in cropland, and heavier animalivorous bats in secondary forest. Although our results highlight the importance of higher-quality matrix habitats to support elevated functional and taxonomic bat diversity, the conservation of bat species that perform different ecological functions in the mosaic of human-modified habitats also depends on the irreplaceable conservation value of well-preserved primary forests. Our study based on a pooled analysis of individual studies provides novel insights into the effects of different human-modified habitats on Neotropical bat assemblages.  相似文献   

12.
Although primary forests are important for biological conservation, the value of secondary forests for forest-dependent organisms needs to be evaluated when habitat restoration is required. We examined whether flower-visiting insects can use secondary forests as alternative habitats to primary forests. In particular, we compared assemblages of bees (Anthophila) and flower longhorn beetles (Lepturinae: Cerambycidae) in young secondary, mature secondary, and primary forests. Our results showed that more bee species were captured in primary and mature secondary forests than in young secondary forests, and flower longhorn beetle species were captured more frequently in primary forests than in mature and young secondary forests. Ordination showed that the communities in the three forest types were not statistically identical, which indicated that secondary forests cannot provide an absolute alternative habitat to primary forests for bees and flower longhorn beetles. However, the results also suggest that as secondary forests mature, more primary forest species would be able to use secondary forests as habitats. This implies that restoration from other land uses, such as monoculture plantations, to secondary forests could help to promote the faunal biodiversity of primary forests.  相似文献   

13.
陈又清  李巧  王思铭 《昆虫学报》2009,52(12):1319-1327
为揭示紫胶林-农田复合生态系统地表甲虫多样性, 于2006-2007年在云南省绿春县牛孔乡采用陷阱法调查了天然紫胶林、人工紫胶林和旱地的地表甲虫群落。共采集标本1 678头, 分别隶属于24科120种, 其中步甲科(Carabidae)和金龟科(Scarabaeidae)种类最丰富, 均占全部种类的12.50%。拟步甲科(Tenebrionidae)个体数量最丰富, 占个体总数的64.48%; 金龟科次之, 占个体总数的17.58%。大多数科的物种数和个体数在不同土地利用生境中的分布没有显著差异, 而步甲科、隐翅甲科(Staphylinidae)、叩甲科(Elateridae)、拟步甲科、瓢虫科(Coccinellidae)和小蠧科(Scolytidae)在不同土地利用生境中的分布有显著差异。天然紫胶林地表甲虫个体数量最少, 物种较丰富, 优势度最低, 多样性最高; 人工紫胶林个体数和物种数均丰富, 优势度和多样性居中; 旱地个体数量最多, 物种最贫乏, 优势度最高, 多样性最低。种级水平的聚类分析体现出人工紫胶林与旱地之间在种类组成上距离较近; 而科级水平的聚类反映出人工紫胶林和天然紫胶林更接近。结果提示, 紫胶林-农田复合生态系统具有区域内土地利用方式多样化的特点; 天然紫胶林在维持地表甲虫多样性水平上具有重要作用, 而人工紫胶林虽具有积极作用, 但仍需进一步恢复。  相似文献   

14.
We examine the effect of selective timber extraction, and corresponding forest canopy loss, on arboreal dung beetles in the tropical rainforests of Sabah, Malaysian Borneo. Changes in vertical distribution of beetles are measured through differences in the abundance of beetles in ground-based pitfall traps in primary, logged and plantation forest. Previous research has demonstrated that arboreal dung beetles are not generally collected in pitfall traps in primary forest, but are present in large numbers above the ground in canopy vegetation: the presence of arboreal beetles in pitfalls in areas of reduced or modified canopy cover may therefore reflect a response to the absence or modification of their usual habitat, and the proliferation of these beetles nearer to the ground. In this paper, statistically significant differences are found in the abundance of beetles in ground pitfall traps from logged forest compared to primary forest. Results show that virtually no arboreal dung beetles are recorded in primary forest traps, with an increased abundance of arboreal dung beetles in traps from logged and plantation forest, with 1.72% of the total number of arboreal beetles recorded from primary forest, 22.32% from logged forest, and 75.96% from plantation forest. The presence of arboreal dung beetles in plantations demonstrates that arboreal dung beetles can survive outside their normal habitat, and we relate these observations to adaptations to upper rainforest canopy conditions, and proliferation of these microclimatic conditions in man-made habitats. Results are also discussed in terms of their relevance to the measurement of species richness and diversity in logged and other derived ecosystems, where mixing of the ground-based and arboreal faunas occurs.  相似文献   

15.
Conservation management can no longer rely on protecting pristine habitats, but must consider the wider landscape. This is especially true on oceanic islands where endemic species are believed to be particularly susceptible to the extinction risks that accompany land conversion. Despite this, there is a paucity of studies examining how endemic communities on oceanic islands may be distributed across such human-modified habitats. Taking Príncipe Island in West Africa as a case study, we investigate how avian communities vary across the habitats (primary forest, secondary forest, agricultural areas) of this globally important centre of endemism. Here, recent policy reforms aimed at poverty alleviation and increased food production are rapidly altering the current land-use mosaic. Across all habitats, 27 bird species were encountered. Survey points in secondary forest and agricultural areas were, on average, more diverse and held higher overall abundances of birds than those within primary forest. This was true for both the entire avian assemblage and the endemic species alone. Nevertheless, two IUCN-listed species were restricted to primary forest, and many other endemics occurred at higher densities within this habitat. We demonstrate that agricultural areas and novel habitats, such as secondary forest, can hold high abundances of endemic species and thus have the potential to act as a resource for biodiversity conservation. A double-stranded approach to conservation is therefore required that both protects the integrity of the primary forest and controls the rapid changes in agricultural land-use to ensure that it continues to support a large component of the endemic avifauna.  相似文献   

16.
The traditional shade cacao plantations (cabrucas) of southern Bahia, Brazil, are biologically rich habitats, encompassing many forest-dwelling species. However, a critical question for the conservation management of this specific region, and the highly fragmented Atlantic forest in general, is to what extent the conservation value of cabrucas relies on the presence of primary forest habitat in the landscape. We investigated the relative importance of cabrucas and forests for the conservation of five diverse biological groups (ferns, frogs, lizards, birds and bats) in two contrasting landscapes in southern Bahia, one dominated by forest with some interspersed cabrucas, and one dominated by cabrucas with interspersed forest fragments. The community structure (richness, abundance and diversity) of all biological groups differed between cabrucas and forests, although these differences varied among groups. A high number of forest species was found in the cabrucas. However, there were pronounced differences between the two landscapes with regard to the ability of cabrucas to maintain species richness. Irrespective of the biological group considered, cabrucas located in the landscape with few and small forest fragments supported impoverished assemblages compared to cabrucas located in the landscape with high forest cover. This suggests that a greater extent of native forest in the landscape positively influences the species richness of cabrucas. In the landscape with few small forest fragments interspersed into extensive areas of shade cacao plantations, the beta diversity of birds was higher than in the more forested landscape, suggesting that forest specialist species that rarely ventured into cabrucas were randomly lost from the fragments. These results stress both the importance and the vulnerability of the small forest patches remaining in landscapes dominated by shade plantations. They also point to the need to preserve sufficient areas of primary habitat even in landscapes where land use practices are generally favorable to the conservation of biodiversity.  相似文献   

17.
Habitat fragmentation results in landscape configuration, which affects the species that inhabit it. As a consequence, natural habitat is replaced by different anthropogenic plantation types (e.g. pasture, agriculture, forestry plantations and urban areas). Anthropogenic plantations are important for biodiversity maintenance because some species or functional groups can use it as a complementary habitat. However, depending on plantation permeability, it can act as a barrier to the movement of organisms between habitat patches, such as forest fragments, reducing functional connectivity for many species. Anthropogenic plantations are becoming the most common land use and cover type in the Anthropocene and biodiversity conservation in fragmented landscapes requires information on how different plantation types affect the capacity of the species to move through the landscape. In this study, we evaluated the influence of the type and structure of plantations on the movement of two forest‐dependent understory bird species – plain antvireo (Dysithamnus mentalis) and flavescent warbler (Myiothlyps flaveola) – within a highly fragmented landscape of Atlantic Forest hotspot. Knowing that forestry plantation is assumed to be more permeable to dependent forest bird species than open ones, we selected six study areas containing a forest fragment and surrounding plantation: three with sugarcane plantation and three with Eucalyptus sp. plantation. We used playback calls to stimulate the birds to leave forest fragments and traverse the plantations. Control trials were also carried out inside the forest fragments to compare the distances crossed. We observed that individuals moved longer distances inside forest than between plantation types, which demonstrate that plantations do constrict the movements of both species. The two plantation types equally impeded the movements of the species, suggesting the opposite of the general assumption that forestry plantations are more permeable. Our results indicate that, for generalist species, plantation type does not matter, but its presence negatively impacts movement of these bird species. We highlight that plantations have negative influences on the movements of common bird species, and discuss why this is important when setting conservation priorities.  相似文献   

18.
Biodiversity conservation requires strategies that encompass a variety of land uses and habitat diversity. In this study, we used sites of high ecological interest identified on the basis of the distribution of priority plant and vertebrate species to assess the implications of habitat diversity for conservation management in the Mediterranean mosaic landscape. 40% of the priority species occur in open habitats that depend on continued human presence and low-intensity land-use activities. Furthermore, 70% of the sites have more than one species habitat and 15% of sites contain more than four different species habitats. By explicitly integrating localized habitat variation, conservation planning can address the multiple conservation issues at stake in regions of high landscape diversity to provide clear and effective management objectives.  相似文献   

19.
Agricultural expansion and intensification are major threats to global biodiversity, ecological functions, and ecosystem services. The rapid expansion of oil palm in forested tropical landscapes is of particular concern given their high biodiversity. Identifying management approaches that maintain native species and associated ecological processes within oil palm plantations is therefore a priority. Riparian reserves are strips of forest retained alongside rivers in cultivated areas, primarily for their positive hydrological impact. However, they can also support a range of forest‐dependent species or ecosystem services. We surveyed communities of dung beetles and measured dung removal activity in an oil palm‐dominated landscape in Sabah, Malaysian Borneo. The species richness, diversity, and functional group richness of dung beetles in riparian reserves were significantly higher than in oil palm, but lower than in adjacent logged forests. The community composition of the riparian reserves was more similar to logged forest than oil palm. Despite the pronounced differences in biodiversity, we did not find significant differences in dung removal rates among land uses. We also found no evidence that riparian reserves enhance dung removal rates within surrounding oil palm. These results contrast previous studies showing positive relationships between dung beetle species richness and dung removal in tropical forests. We found weak but significant positive relationships between riparian reserve width and dung beetle diversity, and between reserve vegetation complexity and dung beetle abundance, suggesting that these features may increase the conservation value of riparian reserves. Synthesis and applications: The similarity between riparian reserves and logged forest demonstrates that retaining riparian reserves increases biodiversity within oil palm landscapes. However, the lack of correlation between dung beetle community characteristics and dung removal highlights the need for further research into spatial variation in biodiversity–ecosystem function relationships and how the results of such studies are affected by methodological choices.  相似文献   

20.
The abandonment of marginal areas and the decline of traditional small-scale cattle-breeding is bringing about substantial changes in many areas of the Alpine mountain belt. Extensively exploited pastures, which were colonized by typical ecological communities, are now being replaced by shrublands and forests. In this paper, we evaluate the effectiveness of the maintenance of small pastures for dung beetle (Scarabaeoidea: Geotrupidae, Aphodiidae, Scarabaeidae) conservation in a protected area of the north-western Italian Alps. From July until September 2007, we studied the dung beetle coenosis in the main habitats of the mountain belt: beech forest, scots pine forest, mountain pine forest and pasture. Twenty-three species were sampled. We compared abundance, species richness, α-diversity, evenness and species turnover between the four habitat assemblages and performed a correspondence analysis based on dominance patterns of the three families. Two main ensembles were identified: a pasture ensemble, highly diverse and dominated by Scarabaeidae, and a closed habitats ensemble, less structured and dominated by Aphodiidae and Geotrupidae. Combining habitat specificity and fidelity, the IndVal method showed that half of the species collected made a strong habitat selection toward pasture, while only C. granarius (Aphodiidae) was a reliable indicator of woody areas. We therefore conclude that the loss of extensively exploited pastures may bring about fundamental changes in dung insect communities. In protected areas, a management policy intended to preserve the traditional, sustainable human activities within the mountain belt is highly recommended for the conservation of these insects.  相似文献   

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