共查询到20条相似文献,搜索用时 265 毫秒
1.
2.
Sophie O. Vanwambeke Eric F. Lambin Markus P. Eichhorn Stéphane P. Flasse Ralph E. Harbach Linda Oskam Pradya Somboon Stella van Beers Birgit H. B. van Benthem Cathy Walton Roger K. Butlin 《EcoHealth》2007,4(1):37-51
Land-use change, a major constituent of global environmental change, potentially has significant consequences for human health
in relation to mosquito-borne diseases. Land-use change can influence mosquito habitat, and therefore the distribution and
abundance of vectors, and land use mediates human–mosquito interactions, including biting rate. Based on a conceptual model
linking the landscape, people, and mosquitoes, this interdisciplinary study focused on the impacts of changes in land use
on dengue and malaria vectors and dengue transmission in northern Thailand. Extensive data on mosquito presence and abundance,
land-use change, and infection risk determinants were collected over 3 years. The results of the different components of the
study were then integrated through a set of equations linking land use to disease via mosquito abundance. The impacts of a
number of plausible scenarios for future land-use changes in the region, and of concomitant behavioral change were assessed.
Results indicated that land-use changes have a detectable impact on mosquito populations and on infection. This impact varies
according to the local environment but can be counteracted by adoption of preventive measures. 相似文献
3.
We studied the ecological characteristics of 45–50‐yr‐old subtropical dry forest stands in Puerto Rico that were growing on sites that had been deforested and used intensively for up to 128 yr. The study took place in the Guánica Commonwealth Forest. Our objective was to assess the long‐term effects of previous land use on this forest—i.e., its species composition, structure, and functioning. Previous land‐use types included houses, farmlands, and charcoal pits. Stands with these land uses were compared with a nearby mature forest stand. The speed and path of forest recovery after deforestation and land‐use abandonment depended on the conditions of the land. Study areas where land uses had removed the forest canopy and altered soil conditions (houses and farmlands) required a longer time to recover and had a different species composition than study areas where land uses retained a forest canopy (charcoal pits). Different forest attributes recovered at different rates. Crown area index, stem density, and litterfall rate recovered faster than stemwood and root, biomass, tree height, and basal area. Where previous land uses removed the canopy, Leucaena leucocephala, a naturalized alien pioneer species, dominated the regrowth. Native species dominated abandoned charcoal pits and mature forest. The change in species composition, including the invasion of alien species, appears to be the most significant long‐term effect of human use and modification of the landscape. 相似文献
4.
Mesoamerican biodiversity is increasingly threatened by anthropogenic destruction of natural land cover. Habitat degradation and climate change are primary threats to specialized forest odonate species that are important model organisms for forest health and defining conservation units. The extreme niche specialization of Megaloprepus caerulatus, the world’s largest extant odonate, makes it well suited as an indicator for changing environmental conditions. Megaloprepus, which is considered to be a monospecific genus, is highly dependent on old growth forests whose water filled tree holes are limiting reproductive resources for this species. Here, we focus on the question how historical and recent fragmentation events, strong niche conservatism and ecological conditions have affected population dynamics, viability and the species status in this evolutionarily old genus. Two mitochondrial sequence markers (ND1 and 16S rRNA) and a set of microsatellites were used to analyze population structure and genetic diversity of M. caerulatus in the northern part of its distributional range. Results suggested an absence of gene flow and no shared haplotypes among the study populations. Statistical parsimony indicated high sub-structuring among populations with sequence diversity similar to levels found at the species level compared to other odonates. In sum, the genetic data suggest that Megaloprepus may actually consist of more than one species. The taxonomic status of the group should be revised in light of the three distinct genetic clusters found in different forest regions. The results may also allow insights into the impact of recent and historical habitat fragmentation on a strong Neotropical forest restricted insect species. 相似文献
5.
6.
Navjot S. Sodhi David S. Wilcove R. Subaraj Ding Li Yong Tien Ming Lee Henry Bernard Susan L. H. Lim 《Biodiversity and Conservation》2010,19(2):485-490
We report odonate and butterfly extinctions on Pulau Mengalum (Sabah) between 1928 and 2007. Pulau Mengalum has lost all of
its closed-canopy forest; 55.5% of the odonates and 40% of the butterflies present in 1928 have likely been extirpated. Fourteen
and five species of odonates and butterflies found by us were new records for the island, respectively. It is unclear if newly
recorded species were missed by previous surveyors in 1928 or if they have colonized the island after that time. While our
study indicates that deforestation is a serious threat to tropical insects, it remains unclear if deforested areas provide
opportunities for new colonists. 相似文献
7.
BIANCA WOHLFAHRT DIRK JOHANNES MIKOLAJEWSKI GERRIT JOOP FRANK SUHLING 《Freshwater Biology》2006,51(1):76-84
1. Behavioural differences among prey species may result from evolutionary adaptations that facilitate coexistence with different predators and influence vulnerability to predators. It has been hypothesised that prey species modify their behaviour in relation to the risk posed by particular predators. 2. We examined the relationship between anti‐predator behaviour and predation risk in five species of larval odonates in combination with three predatory fish species (perch, gudgeon and rudd) that differ in foraging behaviour. The odonates, Platycnemis pennipes, Coenagrion puella, Lestes sponsa, Sympetrum striolatum and Libellula depressa, differ with regard to their life cycle and habitat, including water depth, occurrence in temporary ponds and co‐existence with fish. 3. The odonate species differed in their response to fish: (i) Two species showed a flexible response. Larval C. puella reduced activity in the presence of fish, regardless of species, whereas L. depressa altered their activity only in the presence of gudgeon. (ii) Independent of fish species, all odonates except L. depressa exhibited spatial avoidance of fish. This was interpreted as a more general anti‐predator response. (iii) In some cases the odonates showed no response to predators and their behaviour was thus independent of predation risk. 4. Our results confirm that all odonates responded to the presence of at least some predatory fish, and that some odonate species discriminated between fish species. However, we found no significant correlation between behavioural modifications and predation risk, indicating that anti‐predator responses and predation risk depend on the particular predator and the species being preyed on. 相似文献
8.
Abstract Natural forest expansion is one of the most relevant landscape changes in many temperate countries. Although large areas are involved, relatively few studies have been carried out with the objective of unravelling the specific impact of the individual factors characterising the sites prone to such a process. The aim of this article is to present a research tool for assessing the factors characterising farmland sites prone to natural conversion from crop growing and pasture to forests and other wooded land (OWL), and for predicting the probability of such a land-use change. The methodological approach is based on multinomial logistic regression. As a case study, the approach was applied to land-use classification repeated on the same sites in a large area of central Italy on two successive occasions, spanning two decades, from the beginning of the 1980s up to 2002. Of all the factors assessed, landscape attributes were identified as a sufficient subset for quantitative prediction of change from farmland to OWL or to forest. The tested modelling approach is explicitly empirical and planning-oriented. From a quantitative point of view, the precision of the models may be only indicative for assessing land-use change probability for single observations, while it is appropriate for predicting mean probabilities at a landscape mapping level, where it is possible to sample a number of sites. At this level, the approach is a useful tool for simulating future landscape scenarios related to natural forest expansion. 相似文献
9.
Ant diversity and bio-indicators in land management of lac insect agroecosystem in Southwestern China 总被引:1,自引:0,他引:1
You-qing Chen Qiao Li Yan-lin Chen Zhi-Xing Lu Xing-yin Zhou 《Biodiversity and Conservation》2011,20(13):3017-3038
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
10.
In the lowland moist forest of Barro Colorado Island (BCI), Panama, larvae of four common species of odonates, a mosquito,
and a tadpole are the major predators in water-filled tree holes. Mosquito larvae are their most common prey. Holes colonized
naturally by predators and prey had lower densities of mosquitoes if odonates were present than if they were absent. Using
artificial tree holes placed in the field, we tested the effects of odonates on their mosquito prey while controlling for
the quantity and species of predator, hole volume, and nutrient input. In large and small holes with low nutrient input, odonates
depressed the number of mosquitoes present and the number that survived to pupation. Increasing nutrient input (and consequently,
mosquito abundance) to abnormally high levels dampened the effect of predation when odonates were relatively small. However,
the predators grew faster with higher nutrients, and large larvae in all three genera reduced the number of mosquitoes surviving
to pupation, even though the abundance of mosquito larvae remained high. Size-selective predation by the odonates is a likely
explanation for this result; large mosquito larvae were less abundant in the predator treatment than in the controls. Because
species assemblages were similar between natural and artificial tree holes, our results suggest that odonates are keystone
species in tree holes on BCI, where they are the most common large predators.
Received: 4 November 1996 / Accepted: 11 April 1997 相似文献
11.
Tae Sato Satoshi Ito Yasushi Mitsuda Norihisa Soen 《Landscape and Ecological Engineering》2010,6(1):89-98
We examined the impacts of land-use history on the species composition and diversity of a warm-temperate riparian forest landscape
in Kyushu, southern Japan, focusing on the relationship between evergreen oaks and deciduous trees in natural and seminatural
forests. The species composition of 59 plots was classified into four types (A to D). Type A, which showed a significant bias
towards sites not subject to nonforest land use since 1947, had high species diversity consisting of (1) many lucidophyllous
components of the region, including the rare indigenous oak Quercus hondae, and (2) summergreen tree species of varying dominance and number representing unique or locally rare elements of the riparian
landscape in this warm-temperate region. Type B was dominated by a common species of oak, Q. glauca, and displayed less clear distribution bias with land-use history. In contrast to types A and B, types C and D, which were
characterized by high dominance of deciduous trees, had negative bias away from sites that had been under forest land use
in 1947. Presumably, intensive anthropogenic disturbances associated with nonforest land uses had expanded the habitats for
deciduous trees. This phenomenon was represented by the establishment of forests (type D) dominated by Ulmus davidiana var. japonica (UDJ) after it had been released from the suppression of evergreen forest trees during a period of nonforest land use that
prevents the successful recovery of evergreen trees. From these results we conclude that the impacts of land-use history on
the diversity of warm-temperate riparian forest landscape are multiphased: a period of nonforest land use has a strong negative
impact on lucidophyllous forest trees represented by the rare indigenous oak Q. hondae; release from the suppressive effects of the lucidophyllous species then encourages establishment of locally rare deciduous
tree flora represented by UDJ, which continue to persist for decades after abandonment of nonforest land use. 相似文献
12.
Abstract The relationship between the distribution of predators (fish, odonates and water beetles) and prey assemblages (amphibian larvae) was investigated in the tropical rainforest of central Amazonas, Brasil. The anuran community uses a variety of waterbodies for reproduction, ranging from streams and streamside ponds to isolated forest ponds. Predators in this system include fish in streams and streamside ponds, and invertebrates (primarily odonate naiads and beetles) in forest ponds. Tadpole species richness and assemblage structure were related to fish density and species richness. No relationships between tadpole assemblages and abiotic pond characteristics were detected. The presence offish explained much of the variation in both species composition and species richness within and among ponds. Some species of tadpole were consistently found to coexist with high densities of fish. Path analyses suggest that while fish have a strong direct effect on tadpole associations and species richness, they also have an indirect effect through invertebrate predators (odonate larvae and coleopteran beetles). Prey survival-strategies such as palatability and behaviour may explain how tadpole species composition is affected by predators at the community level. These findings suggest that the observed patterns of habitat use by larval anurans may be structured in response to the distribution of key predators (fish) in this system. 相似文献
13.
Samuel Renner Eduardo Périco Marina Schmidt Dalzochio Göran Sahlén 《Journal of Insect Conservation》2018,22(1):113-125
The biogeographical region known as the Pampa biome in southern Brazil, was originally mainly covered with open fields or grassland, with areas of riparian forest surrounding the water bodies. Today this landscape appears highly fragmented due to agricultural activities such as rice cultivation, extensive cattle farming, and forest plantations. Studies have shown that the Pampa biome has high levels of biodiversity and endemism, but with regard to invertebrates, this biome is still one of the least known in Brazil. We therefore designed a study comparing the dragonfly (Odonata) communities to environmental and landscape features in this area, measuring diversity by species richness, relative abundance and Shannon index. Our results showed that the Pampa is a biome very rich in odonates, and that the species communities are highly dependent on the environmental conditions of the area. Habitats such as Rivers/Streams, bordered by native grasslands and riparian forests, were shown to harbour communities that were ecologically more complex and sensitive than other habitat types. Man-made lakes and agricultural areas displayed lower levels of biodiversity and odonate communities dominated by generalist species. By combining data on the communities of Odonata and other taxa, our analyses may be instrumental in determining priority areas for future conservation measures within the area. 相似文献
14.
Tyler M. Harms Karen E. Kinkead Stephen J. Dinsmore 《Journal of Insect Conservation》2014,18(3):307-315
Odonates contribute highly to global biodiversity and are considered good indicators of environmental quality, but they are under-studied and quantitative information on their habitat associations is lacking. Our objective was to examine the effects of landscape configuration on site occupancy and movement dynamics of four odonate species in Iowa: Tramea onusta, Epitheca princeps, Pantala flavescens, and Calopteryx maculata. We conducted standardized visual encounter surveys for odonates at 233 public properties in Iowa from 2007 to 2011 and computed landscape variables within a 200, 600 m, and 1 km radius of each surveyed site. Using a robust design occupancy model in Program MARK, we estimated detection probability and site occupancy, site extinction, and site colonization probabilities for each species. We found few significant effects of landscape variables on site occupancy, extinction, or colonization, although landscape variables at 600 m were included in the best model for all species. Detection probability (SE) ranged from 0.30 (0.04) for Pantala flavescens to 0.49 (0.04) for Calopteryx maculata. Our study provides information to aid habitat restoration and management efforts on sites having suitable characteristics in the surrounding landscape and ultimately help conserve odonates. 相似文献
15.
土地利用变化对花岗岩红壤底土溶解性有机质数量和光谱特征的影响 总被引:2,自引:0,他引:2
了解底土溶解性有机质(DOM)的数量和化学结构对土地利用变化的响应,对科学评价区域土壤有机质动态和碳库稳定性具有重要意义。通过选取花岗岩红壤丘陵区同一景观单元的天然林地(常绿阔叶林)以及由此转变而来的杉木人工林、板栗园和坡耕地,采用化学分析结合光谱扫描(紫外光谱、二维荧光光谱和傅里叶变换红外光谱)技术,研究底土(0.2—1 m)和表土(0—0.2 m)DOM数量和结构对土地利用变化的响应差异,结果表明:58%—87%的DOM贮存在底土中。天然林地土壤的DOM数量最为丰富,底土DOM的宏观化学结构比表土更为简单,以碳水化合物、类蛋白为主。天然林转变为其他利用方式后,底土DOM的损失量(26%—41%)超过表土(12%—49%),冬季比夏季更为凸显;这反映底土DOM数量对人为干扰和植被变化的高度敏感性。同时,底土DOM宏观化学结构趋于复杂化,芳香类、烷烃类和烯烃类的化学抗性物质出现积累的现象。DOM光谱曲线形状、特定峰值、特征值对土地利用的响应敏感,对人为干扰后植被、土壤有机质的变化具有生态指示意义。研究显示,天然林地转变为其他利用方式后,不仅导致底土DOM的损失,也显著降低土壤有机质品质,长期上削弱底土的碳库稳定性和碳吸存能力。 相似文献
16.
Trophic ecology of adult male Odonata. I. Dietary niche metrics by foraging guild,species, body size,and location
下载免费PDF全文
![点击此处可从《Ecological Entomology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
1. Information on the dietary niches of adult odonates is sparse, as they are highly mobile and evasive animals, which makes them difficult to observe in their natural habitat. Moreover, there is a lack of knowledge on how varying behavioural traits of odonates relate to phenomena like niche partitioning. 2. This study investigated niche partitioning amongst odonate species, foraging guilds and size classes in a riverine system in the Eastern Cape province of South Africa. A combination of stable isotope and fatty acid‐based niches was used to infer odonate feeding. 3. Both fatty acid and stable isotope‐based niches showed that there was niche separation amongst odonates that forage in flight (fliers) and those that forage from a perch (perchers), amongst odonates of different size classes (damselflies, medium‐ and large‐sized dragonflies), and amongst species, although varying levels of niche overlap were observed in each case. 4. Niche sizes of odonates varied between an upstream and a downstream site. Generally greater niche overlap was recorded at the narrow upstream site (associated with low insect emergence rates) than the wider downstream site (associated with high insect emergence rates), indicating that a greater degree of resource sharing occurred at the upstream site where aquatic food was less abundant. 5. The findings of this study suggest that dietary niches of odonates can be influenced by foraging guild, body size, and/or environmental conditions, and additional study in a variety of regions is recommended to determine the greater applicability of these findings. 相似文献
17.
C. W. Woodall B. F. Walters M. B. Russell J. W. Coulston G. M. Domke A. W. D’Amato P. A. Sowers 《Ecosystems》2016,19(8):1401-1417
The dynamics of land-use practices (for example, forest versus settlements) is often a major driver of changes in terrestrial carbon (C). As the management and conservation of forest land uses are considered a means of reducing future atmospheric CO2 concentrations, the monitoring of forest C stocks and stock change by categories of land-use change (for example, croplands converted to forest) is often a requirement of C monitoring protocols such as those espoused by the Intergovernmental Panel on Climate Change (that is, Good Practice Guidance and Guidelines). The identification of land use is often along a spectrum ranging from direct observation (for example, interpretation of owner intent via field visits) to interpretation of remotely sensed imagery (for example, land cover mapping) or some combination thereof. Given the potential for substantial differences across this spectrum of monitoring techniques, a region-wide, repeated forest inventory across the eastern U.S. was used to evaluate relationships between forest land-use change (derived from a forest inventory) and forest cover change (derived from Landsat modeling) in the context of forest C monitoring strategies. It was found that the correlation between forest land-use change and cover change was minimal (<0.08), with an increase in forest land use but a net decrease in forest cover being the most frequent observation. Cover assessments may be more sensitive to active forest management and/or conversion activities that can lead to confounded conclusions regarding the forest C sink (for example, decreasing forest cover but increasing C stocks in industrial timberlands). In contrast, the categorical nature of direct land-use field observations reduces their sensitivity to forest management activities (for example, clearcutting versus thinning) and recent disturbance events (for example, floods or wildfire) that may obscure interpretation of C dynamics over short time steps. While using direct land-use observations or cover mapping in forest C assessments, they should not be considered interchangeable as both approaches possess idiosyncratic qualities that should be considered when developing conclusions regarding forest C attributes and dynamics across large scales. 相似文献
18.
Pellets of proof: First glimpse of the dietary composition of adult odonates as revealed by metabarcoding of feces
下载免费PDF全文
![点击此处可从《Ecology and evolution》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kari M. Kaunisto Tomas Roslin Ilari E. Sääksjärvi Eero J. Vesterinen 《Ecology and evolution》2017,7(20):8588-8598
Recent advances in molecular techniques allow us to resolve the diet of unstudied taxa. Odonates are potentially important top‐down regulators of many insects. Yet, to date, our knowledge of odonate prey use is based mainly on limited observations of odonates catching or eating their prey. In this study, we examine the potential use of metabarcoding in establishing the diet of three adult odonate species (Lestes sponsa, Enallagma cyathigerum, and Sympetrum danae) at a site in southwestern Finland. To this purpose, we compared three different methods for extracting DNA from fecal samples: the Macherey‐Nagel Nucleospin XS kit, a traditional salt extraction, and the Zymo Research Fecal Microprep kit. From these extracts, we amplified group‐specific mitochondrial markers (COI and 16S rRNA) from altogether 72 odonate individuals, and compared them to comprehensive reference libraries. The three odonate species show major overlap in diet, with no significant differences between individuals of different size and/or gender, reflecting opportunistic foraging of adult odonates. Of a total of 41 different prey species detected, the most frequently consumed ones were Diptera, with additional records of six other orders. Based on our data, the best DNA extraction method is the traditional salt extraction, as it provides the most information on prey content while also being the most economical. To our knowledge, this is the first study to resolve the species‐level diet of adult odonates. Armed with the appropriate methodological caveats, we are ready to examine the ecological role of odonates in both terrestrial and aquatic food webs, and in transferring subsidies between these two realms. 相似文献
19.
《Ecography》2003,26(1):13-20
Dispersal has a potentially profound effect on the dynamics of populations especially when a population occupies a patchy habitat. Ponds surrounded by terrestrial landscape are an example of patchy distribution of physical conditions and constitute "islands" for odonates. Few studies have focussed on dispersal in odonates. We have used the direct method of dispersal observing (capture-mark-recapture technique) in order to estimate the degree of linkage in three patchy populations of odonate localised on three ponds. We also examined the differences in dispersal ability within and among three species ( Coenagrion puella , Coenagrion scitulum and Libellula depressa ). The ponds were situated in southwest France on a limestone plateau. In this arid area, these ponds constitute the only surface water available and are relatively sparsely distributed. The size of the ponds ranged from 48 to 79 m2 and they were 200 and 775 m apart. We demonstrated that three factors influence the dispersal ability of these odonates. The first is represented by the abiotic factors and especially weather conditions. This determines the number of days that dispersal is possible. The second is interspecific differences. We showed that sensitivity to weather conditions, species size and species behaviour influence dispersal ability. The third factor is the intraspecific characteristics. We demonstrated that there are differences in dispersal ability according to sex and age. To conclude, we discuss the importance of pond management to maintain the existing odonate populations and to facilitate introduction of new populations in this region where little exchange occurs between ponds. 相似文献
20.
Influence of urbanization on riparian forest diversity and structure in the Georgia Piedmont, US 总被引:1,自引:0,他引:1
Riparian forests are increasingly threatened by urban expansion and land use change worldwide. This study examined the relationships
between landscape characteristics and woody plant diversity, structure, and composition of small order riparian corridors
along an urban-rural land use gradient in the Georgia Piedmont, US. Riparian plant diversity, structure, and composition were
related to landscape metrics and land use. Species richness was negatively associated with impervious surfaces and landscape
diversity, and positively associated with forest cover and largest forest patch index. Shannon species diversity was strongly
related to the biomass of non-native species, especially for the regeneration layer. Urban sites were characterized by high
richness of non-native and pioneer species. Developing sites were dominated by the non-native shrub, Ligustrum sinense Lour., and several native overstory trees, mainly Acer negundo L. While agricultural and managed forest sites were composed of ubiquitous species, unmanaged forest sites had a structurally
distinct midstory indicative of reduced disturbance. Urban and agricultural land uses showed decreased native stem densities
and signs of overstory tree regeneration failure. Results from this study highlight the impact of the surrounding landscape
matrix upon riparian forest plant diversity and structure. 相似文献