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1.
Habitat restoration strategies for fragmented high Andean forest landscapes must consider the influence of within‐patch habitat quality on bird abundance. I examined vegetation and bird abundance at three locations within a highly fragmented Polylepis forest landscape in the Cordillera Vilcanota, southern Peru. Across the landscape, there was significant variation in the vegetation structure of Polylepis forest patches of different size categories, especially in terms of tree girth, tree height, tree density, and canopy vegetation structure. Principal Component Analysis extracted five factors of habitat quality, which together accounted for 74.2% of the variability within 15 habitat variables. Polylepis bird species differed in their responses to habitat quality but, overall, variation in Polylepis bird abundance was not fully captured by the range of habitat quality variables. Tall, dense vegetation cover was clearly important for 11 conservation‐important species, a high density of large trees was important for 10 species and primary forest ground cover was important for eight species. Habitat quality exhibited no significant influence on the abundance of only one species –Asthenes urubambensis. The abundance of seven species was associated with lower elevation forest, but only one species was associated with higher elevation forest. Management of habitat quality in large and medium remnant forest patches throughout the Cordillera Vilcanota, particularly in the 3800–4200 m elevation range, will be a cornerstone in ensuring the persistence of the majority of conservation‐important bird species populations. 相似文献
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Abstract: We studied the effects of fragment size, vegetation structure and presence of habitat corridors on the reproductive success of the Des Murs’ Wiretail (Sylviorthorhynchus desmursii Des Murs, Furnariidae), a small (10 g) understorey bird, endemic to South American forests. In a rural landscape of Chiloé Island, southern Chile (42°S; 70°W), we determined the mating and nesting success of wiretails in 28 territories distributed in seven small (1–20 ha) and two large (>300 ha) forest fragments during the 1997–1998 breeding season. Wiretails inhabited dense bamboo thickets in the understorey of forest patches, dense shrublands covering old fields, and dense early successional forest vegetation. Wiretails avoided open pastures. Reproductive success depended solely on the probability of finding mates, and the main factor affecting mating success was the presence of corridors. Mated individuals occupied 72% of the territories in forest patches <20 ha connected by corridors, 73% of the territories in large (>300 ha) fragments, but only 20% of territories in isolated fragments surrounded by pastures. Because of the rapid expansion of pastures in southern Chile, the conservation of wiretails and other understorey birds will depend on the maintenance of travel corridors with dense understorey vegetation between forest fragments. 相似文献
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Abstract: Flower strips near crops may stimulate natural enemies by the provision of nectar and hibernation sites. However, these habitats may also be beneficial for potential pest species. We investigated the dynamics of the cabbage aphid Brevicoryne brassicae (L.) (Homo., Aphididae) and its primary parasitoid Diaeretiella rapae (McIntosh) (Hym., Braconidae) in brussels sprout fields and adjoining flower plots in winter. A wide variety of 14 plant species were included in the study, each established as monoculture plots. Brussels sprout fields and flower plots were established at two sites. One site was located in an open agricultural landscape, the other in a landscape dominated by mixed forest. Brevicoryne brassicae and D. rapae were found on brussels sprout plants but not in the flower plots. Brevicoryne brassicae was initially more abundant in the open landscape, but as their densities declined rapidly in time, no living aphids were recovered at both sites by February. The density of aphids parasitized by D. rapae showed a similar trend, but densities of eight mummies per brussels sprout plant were still present by the end of February. These findings suggest that (i) flower species under investigation do not function as sources of B. brassicae and (ii) brussels sprout plants that are not harvested may not only harbour D. rapae populations that may sustain biological control, but are also likely to act as sources of B. brassicae infestation. 相似文献
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Heidi L. Adams L. Wes Burger Jr. Sam Riffell 《The Journal of wildlife management》2013,77(6):1213-1220
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JI&#;Í REIF PETR VO&#;Í&#;EK KAREL &#;&#;ASTNÝ VLADIMÍR BEJ&#;EK & JI&#;Í PETR 《Ibis》2008,150(3):596-605
The relationship between agricultural intensification and a decline in farmland bird populations is well documented in Europe, but the results are mostly based on data from the western part of the continent. In the former socialist eastern and central European countries, political changes around 1990 resulted in a steep decline in the intensity of agriculture. Therefore, one would expect populations of farmland birds to have recovered under these conditions of lower agricultural intensity. We explored population trends of 19 farmland bird species in the Czech Republic between 1982 and 2003 using data from a large‐scale monitoring scheme, and, additionally, we looked for relationships between such population changes and a number of variables describing the temporal development of Czech agriculture. Most farmland species declined during the focal period, and this decline was steepest in farmland specialists (Northern Lapwing Vanellus vanellus, Skylark Alauda arvensis, Linnet Carduelis cannabina and Yellowhammer Emberiza citrinella). Although the intensity of agriculture was lower after than before 1990, the overall decline continued in most farmland bird species, albeit at a slower rate. The correlations between agricultural intensity and farmland bird decline showed opposite patterns to that found in other European studies, because bird populations were highest in years with the most intensive agriculture. We speculate that this pattern could have resulted from the impact of different driving forces causing farmland bird decline in different periods. The high intensity of agriculture could have caused the decline of the originally abundant populations before 1990. After 1990, the decreasing area of arable land could be the most important factor resulting in the continued decline of farmland bird populations. Our results demonstrate that the drivers of farmland bird population changes could differ across Europe, and thus investigations into the effect of farmland management in different parts of the continent are urgently required. 相似文献
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Joana Santana Luís Reino Chris Stoate Francisco Moreira Paulo F. Ribeiro José L. Santos John T. Rotenberry Pedro Beja 《Ecology and evolution》2017,7(4):1212-1223
Conserving biodiversity on farmland is an essential element of worldwide efforts for reversing the global biodiversity decline. Common approaches involve improving the natural component of the landscape by increasing the amount of natural and seminatural habitats (e.g., hedgerows, woodlots, and ponds) or improving the production component of the landscape by increasing the amount of biodiversity‐friendly crops. Because these approaches may negatively impact on economic output, it was suggested that an alternative might be to enhance the diversity (compositional heterogeneity) or the spatial complexity (configurational heterogeneity) of land cover types, without necessarily changing composition. Here, we develop a case study to evaluate these ideas, examining whether managing landscape composition or heterogeneity, or both, would be required to achieve conservation benefits on avian diversity in open Mediterranean farmland. We surveyed birds in farmland landscapes of southern Portugal, before (1995–1997) and after (2010–2012) the European Union's Common Agricultural Policy (CAP) reform of 2003, and related spatial and temporal variation in bird species richness to variables describing the composition, and the compositional and configurational heterogeneity, of the natural and production components of the landscape. We found that the composition of the production component had the strongest effects on avian diversity, with a particularly marked effect on the richness of farmland and steppe bird species. Composition of the natural component was also influential, mainly affecting the richness of woodland/shrubland species. Although there were some effects of compositional and configurational heterogeneity, these were much weaker and inconsistent than those of landscape composition. Overall, we suggest that conservation efforts in our area should focus primarily on the composition of the production component, by striving to maximize the prevalence of biodiversity‐friendly crops. This recommendation probably applies to other areas such as ours, where a range of species of conservation concern is strongly associated with crop habitats. 相似文献
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Harold N. Eyster;Diane S. Srivastava;Maayan Kreitzman;Kai M. A. Chan; 《Ecography》2022,2022(11):e06240
Human-shared landscapes cover much of Earth, yet their conservation value is contested. This controversy may persist because previous studies have examined species diversity, rather than the processes through which such diversity is maintained. For example, a site exhibiting high diversity may not actually bolster populations if the diversity is only maintained through net immigration. Recent research has begun to isolate the processes that maintain metacommunities and develop functional trait methods to identify these processes. However, the processes underlying bird communities remain obscure. Here, we leverage metacommunity theory, functional trait partitioning and a Bayesian multispecies abundance model to assess whether a shared landscape – woody perennial polyculture farms – bolsters bird diversity. Such farms grow multiple species of food-producing woody perennials together with vegetative groundcover. We surveyed birds and their in situ functional traits across the US Midwest in traditional agriculture, woody perennial polyculture, prairie and woods. We found that woody perennial polycultures exhibited the highest bird diversity and were the most preferred by many species (including threatened ones). Moreover, our functional trait analysis suggests that this diversity is maintained through habitat filtering and competition, rather than merely immigration. Thus, shared landscapes can likely conserve birds by providing a distinct habitat. These results suggest that woody perennial polyculture farms offer substantial potential to support bird populations in the US Midwest. Our study demonstrates the utility of in situ functional trait partitioning within a Bayesian framework to unmask ecological processes and help assess the conservation value of landscapes. 相似文献
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Guillermo Deferrari Carolina Camilión Guillermo Martínez Pastur Pablo Luis Peri 《Biodiversity and Conservation》2001,10(12):2093-2108
Human activities, such as logging, modify the forest structure and the microenvironments of the original Nothofagus forests. The aims of this work were to evaluate changes in the diversity and relative abundance of birds and to analyze their trophic relationships with insect and plant communities along the Nothofagus pumilio forest management cycle. Data was collected using a point sampling method along transects located in different forest structures during the summer season, by direct (sight) and indirect (hearing) recognition following sunrise. Bird diversity and abundance significantly varied along the forest management cycle. Seven new species appeared after harvest, but the total number did not vary by the end of the forest management cycle, and there was no significant loss of species. Bird abundance was directly related to the insect abundance and plant biomass. Relationship between groups (lower plants, monocotyledons and dicotyledonous) is also discussed. Major studies in bird ecology are necessary to develop new silvicultural alternatives based on the more sensitive species to harvest. Forest management strategies and mitigation alternatives must be incorporated into forest planning in order to maintain the original structure of bird communities and the equilibrium with other forest species. 相似文献
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Hemanta Dhakal Hari Prasad Sharma Christopher J. W. McClure Munir Virani Brian W. Rolek Narendra Man Babu Pradhan Krishna Prasad Bhusal 《Ecology and evolution》2022,12(1)
Due to an abundance and diversity of vultures, Nepal is one of the most important countries for vulture conservation. Within Nepal, the Pokhara Valley is especially significant. We examine the distribution of vultures within the Pokhara Valley by conducting counts at 11 potential feeding or roosting sites using point count method. We further surveyed people of the valley regarding their perception of vulture ecology and conservation, knowledge of diclofenac use within the valley, and burial of livestock carcasses. We detected eight species of vultures, four of which are currently threatened with extinction. White‐rumped vulture Gyps bengalensis, Egyptian vulture Nephron percnopterus, and Himalayan vulture G. himalayensis were the most abundant. Almost all respondents (98%) had sighted the vultures in the wild. Formally educated respondents reported seeing vultures’ slightly more than nonformally educated respondents. Fifty‐eight percent respondents suspected habitat loss was the major threat for the vulture population decline in Pokhara Valley, and 97% respondents were not aware of any diclofenac use. The knowledge of vultures in people with different age groups suggests a more awareness programs are needed for local people, especially those who carry out animal husbandry and provide livestock to the vulture restaurant. 相似文献
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Ramji Gautam;Nabin Baral;Hari Prasad Sharma; 《Ecology and evolution》2024,14(3):e11175
White-rumped vultures (Gyps bengalensis) are critically endangered species, and protecting their habitats, particularly the nesting trees, may have a positive impact on their reproductive success. For a better understanding of vultures' habitat needs, the characteristics of nesting trees should be accounted. In this paper, we compare the characteristics of the trees that have vultures' nests and that do not by randomly select a control tree within a 10 m radius of the nesting tree. We extensively searched and monitored the white-rumped vultures' nests, nesting trees, and nesting tree species in Nepal between 2002 and 2022, and measured the characteristics of sampled trees such as their height, girth, canopy spread, branching orders, and whorls. We recorded 1161 nests of white-rumped vulture in total on 194 trees belonging to 19 species over the past two decades. White-rumped vultures preferred the kapok trees (Bombax ceiba) for nest construction than other tree species (χ2 = 115.38, df = 1, p < .001) as 66.49% of nests were built on them. In the logistic regression model, the number of whorls on a tree, canopy spread, and the height of the first branch determined whether a nest was present or absent on a tree. These results help to prioritize the tree attributes in a habitat conservation plan for vultures. 相似文献
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Na Li Yuehua Sun Hongjun Chu Yingjie Qi Lan Zhu Xiaoge Ping Chunwang Li Zhigang Jiang 《Ecology and evolution》2019,9(17):9634-9643
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《African Journal of Aquatic Science》2013,38(3):277-288
Vallisneria aethiopica and Lagarosiphon ilicifolius are common and abundant submerged macrophytes in Lake Kariba, Zimbabwe. The two species have distinct structural morphologies, with Vallisneria consisting of long ribbon-like leaves, while Lagarosiphon has filiform stems with numerous small alternate leaves. This study investigated the effect of these architectural differences between the two plant species on their epiphytic macroinvertebrate assemblages in the shallow inshore waters of Lake Kariba. Ten sites were sampled on three occasions between May and July 2005. A total of 56 macroinvertebrate taxa was collected, 48 from Lagarosiphon and 45 from Vallisneria. Generally, the two plant species were associated with similar macroinvertebrate communities, but the average abundances of most taxa, and thus the overall macroinvertebrate abundances, were significantly greater on Lagarosiphon. The main macroinvertebrate functional feeding groups found on both plant species were collector-gatherers, grazers and predators, all of which were significantly more abundant on Lagarosiphon. Although the macroinvertebrate assemblages associated with Vallisneria and Lagarosiphon generally consisted of the same taxa, there were distinct and significant differences between them, probably due to the architectural differences between the two submerged macrophytes. 相似文献
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农业景观中的鸟类多样性对生态系统功能和服务的形成与维持具有重要作用。黄淮平原区是我国最重要的农业景观区之一,为探讨区域内农业景观中鸟类多样性特征和不同生境间的差异,在研究区农业景观不同生境中布设样点,调查繁殖期鸟类多样性特征。结果显示:(1)共记录到32科、49属、66种的10044只个体,但优势科属明显;(2)物种丰富度、多样性和均匀度均表现出在沟渠、湖泊生境中较高,农田和村庄生境中相对较低,但物种多度呈现出村庄生境中最高,其次是沟渠和农田生境,湖泊生境中最低;(3)在区系分布上,各生境中均以广布种为主,生态类群上,鸣禽在各生境中均占绝对优势,涉禽和游禽主要分布在沟渠和湖泊生境中,从居留型来看,留鸟是各生境中的主导类群,候鸟、旅鸟和迷鸟比例很低;(4)鸟类群落异质性分析显示,各生境间的相似性总体上较高,表明区域内农业景观中鸟类组成具有较高的重叠性。研究显示农业景观中湖泊和沟渠的存在能有效的提高区域鸟类的丰富度和多样性,而沟渠的存在能有效的提高鸟类个体多度,农田和村庄有助于特定类群多度的增加,因此在未来的区域持续农业景观的构建中一方面要重视自然、半自然非农生境的作用,另一方面也不能忽视不同生物类群对景观异质性响应和对生境特征需求的差异。 相似文献
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We compared the relative contribution of blackwater inundation forest (igapó) and unflooded (terra firme) forest for regional bird species diversity in the lower Rio Negro region. For analyses of habitat preference we used mist-net samples and an unpublished bird species check-list. The igapó forest had lower bird species diversity than the terra firme forest. However, some 14% of the forest bird species in the region are restricted to igapó forest. Species composition was found to be distinct between the understories of the two forest types. Common forest bird guilds in the Neotropics such as ant-following birds avoid igapó forest. The differential habitat selection among birds in the inundated and unflooded forest is likely to result from vegetation structure and biological interactions such as aggressive behaviour. Since the inundated forest has a typical biota, conservation efforts needs to be directed to protect these habitats. Unfortunately, inundation forests are threatened by several human actions, especially dam construction. The extent of protected areas in the Brazilian Amazon is insufficient for the adequate protection of the inundated habitats, because it includes only 3% of the total area. 相似文献
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A fundamental part of developing effective biodiversity conservation is to understand what factors affect the distribution and abundance of particular species. However, there is a paucity of data on ecological requirements and habitat relationships for many species, especially for groups such as reptiles. Furthermore, it is not clear whether habitat relationships for particular species in a given environment are transferable to other environments within their geographical range. This has implications for the type of ‘landscape model’ used to guide management decisions in different environments worldwide. To test the hypothesis that species‐specific habitat relationships are transferable to other environments, we present microhabitat models for five common lizard species from a poorly studied habitat – insular granite outcrops, and then compared these relationships with studies from other environments in south‐eastern Australia. We recorded twelve species from five families, representing 699 individuals, from 44 outcrops in the south‐west slopes of New South Wales. Five lizard species were abundant and accounted for 95% of all observations: Egernia striolata, Ctenotus robustus, Cryptoblepharus carnabyi, Morethia boulengeri and Carlia tetradactyla (Scincidae). Linear regression modelling revealed suites of different variables related to the abundance patterns of individual species, some of which were broadly congruent with those measured for each species in other environments. However, additional variables, particular to rocky environments, were found to relate to reptile abundance in this environment. This finding means that species' habitat relationships in one habitat may not be readily transferable to other environments, even those relatively close by. Based on these data, management decisions targeting reptile conservation in agricultural landscapes, which contain rocky outcrops, will be best guided by landscape models that not only recognize gradients in habitat suitability, but are also flexible enough to incorporate intraspecies habitat variability. 相似文献
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通过野外调查并结合相关文献,共记录四川察青松多白唇鹿国家级自然保护区鸟类17目52科232种,其中,留鸟136种(58.62%),夏候鸟62种(26.72%),旅鸟29种(12.50%),冬候鸟5种(2.16%);古北界物种112种(48.28%),东洋界物种90种(38.79%),广布种30种(12.93%);世界自然保护联盟(IUCN)濒危物种红色名录鸟类15种(濒危3种,易危4种,近危8种);国家Ⅰ级重点保护野生鸟类10种,国家Ⅱ级重点保护野生鸟类24种;中国特有鸟类14种。研究结果表明,在不同生境类型之间,Shannon-Wiener指数为灌丛最高(3.520),裸岩最低(2.548);在不同季节中,夏、秋季物种数目、Shannon-Wiener指数、Pielou均匀度指数均明显高于春、冬季,尤其在夏季,各项指数均达到最大值。鸟类群落多样性指数峰值均出现在海拔4 050~4 200 m,随着海拔升高,各项指数迅速下降,垂直分布格局呈现出明显的中峰模式。保护区具备多样的生境类型和丰富的鸟类物种多样性,其中还包括了相当数量的珍稀濒危物种和特有种,应加强调查研究和保护。研究保护区内鸟类多样性与区系,有助于了解其多样性分布现状和格局,为保护区管理提供科学参考。 相似文献
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Little of Brazil's remaining Atlantic forest is protected, so it is important to assess how well the region's wildlife can persist in areas/habitats outside reserves. We studied bird diversity and abundance during 546 point counts in the Sooretama/Linhares reserve, 200 point counts in 31 forest fragments (10–150 h), and 50 point counts in <30-year-old Eucalyptus plantations, within 7 km of the reserve. Only eight bird species were recorded in Eucalyptus, and this impoverishment, as compared to some Eucalyptus plantations elsewhere in Brazil may be a result of intensive clearance of understory vegetation. Species diversity in forest fragments was significantly lower than in the reserve. Twelve, mostly non-forest or edge species, were significantly commoner in the fragments, but nineteen species were frequent in the reserve but rare or absent in forest fragments. These included two Pyrrhura parakeets, a Brotogeris parakeet, a trogon Trogon, a jacamar Galbula, woodpeckers Piculus and Campephilus, Myrmotherula antwrens, and Hemithraupus and Tachyphonus tanagers. Bird species richness at points in forest fragments did not decline with fragment size, distance from the reserve, or forest quality. However, forest in fragments was more heavily degraded than forest within the reserve and poor forest quality may be the cause of declines in some species. Whilst protection of forest within reserves is a priority, management of forest fragments may aid conservation of some threatened species. 相似文献