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1.
Andean montane rain forests are among the most species‐rich terrestrial habitats. Little is known about their insect communities and how these respond to anthropogenic habitat alteration. We investigated exceptionally speciose ensembles of nocturnal tiger moths (Arctiidae) at 15 anthropogenically disturbed sites, which together depict a gradient of forest recovery and six closed‐forest understorey sites in southern Ecuador. At weak light traps we sampled 9211 arctiids, representing 287 species. Arctiid abundance and diversity were highest at advanced succession sites, where secondary scrub or young forest had re‐established, followed by early succession sites, and were lowest, but still high, in mature forest understorey. The proportion of rare species showed the reverse pattern. We ordinated moth samples by non‐metric multidimensional scaling using the chord‐normalized expected species shared index (CNESS) index at various levels of the sample size parameter m. A distinct segregation of arctiid ensembles at succession sites from those in mature forest consistently emerged only at high m‐values. Segregation between ensembles of early vs. late succession stages was also clear at high m values only, and was rather weak. Rare species were responsible for much of the faunal difference along the succession gradient, whereas many common arctiid species occurred in all sites. Matrix correlation tests as well as exploration of relationships between ordination axes and environmental variables revealed the degree of habitat openness, and to a lesser extent, elevation, as best predictors of faunal dissimilarity. Faunal differences were not related to geographical distances between sampling sites. Our results suggest that many of the more common tiger moths of Neotropical montane forests have a substantial recolonization potential at the small spatial scale of our study and accordingly occur also in landscape mosaics surrounding nature reserves. These species contribute to the unexpectedly high diversity of arctiid ensembles at disturbed sites, whereas the proportion of rare species declines outside mature forest.  相似文献   

2.
The vertical stratification of two species-rich moth families (Lepidoptera: Arctiidae, Geometridae) was analysed in a lowland rain forest in Costa Rica. Moths were trapped with automatic 8 W ultraviolet light traps at three sites in the understorey and canopy of a primary forest at the La Selva Biological Station (10.4° N, 84.0° W). A total of 846 arctiid moths (148 species) and 946 geometrid moths (140 species) were analysed. Species richness and diversity of arctiid moths was significantly lower in the understorey than in the canopy (Fisher's alpha: 24 vs. 49) whereas geometrid moths showed an inverse pattern (Fisher's alpha: 44 vs. 27). This resulted in an overall increase in the proportion of conspicuously coloured species towards the canopy. Moth ensembles were clearly separated in multidimensional scaling ordinations, and differed significantly in their faunal composition and dominance between the strata. The available host plant data suggest that the flight height of moths was determined by larval resource availability. Examples include understorey flyers such as the geometrid genus Eois feeding on Piper, and canopy flyers such as the arctiid moth genera Aclytia, Macrocneme and Poliopastea which feed on lianas.  相似文献   

3.
We studied temporal and spatial dynamics of extremely diverse moth ensembles (Lepidoptera: Pyraloidea) along a gradient of forest disturbance ranging from undisturbed primary tropical rain forest to different kinds of modified forest and open cultivated land at the margin of Mount Kinabalu National Park (Sabah, East Malaysia). We sampled moths by light trapping during two periods (March‐May and August‐September 1997). We collected a total of 7724 individuals representing 680 species during 78 light‐trapping nights at six study sites. Species diversity (Fisher's α) of ensembles in undisturbed primary forest was distinctly higher than in disturbed or secondary forest. More pyraloid moths were attracted in undisturbed primary forest. Samples from disturbed primary or old‐growth secondary forest were statistically indistinguishable from the undisturbed primary forest ensemble in regard to species composition. Thus, pyraloid ensembles from disturbed forest with tall trees remaining appeared to represent impoverished subsets of the undisturbed primary forest community. The more heavily disturbed sites had a distinct fauna and showed a stronger faunal differentiation among each other. Four species of the genus Eoophyla, in which aquatic larvae feed on algae in fast‐running streams benefited prominently from forest disturbance. Temporal variation of ensembles was remarkably concordant across the disturbance gradient. Relative abundance variation of the commonest species was identical at all sites. Overall, pyraloid moths responded more sensitively to anthropogenic habitat alteration than most other moth taxa studied thus far in tropical regions and allowed for an analysis of diversity patterns at a high temporal resolution.  相似文献   

4.
We sampled the diversity of epiphytes (lichens, bryophytes, vascular plants) and moths (Geometridae, Arctiidae) in mature and recovering forest and in open vegetation in the montane belt in Ecuador. No uniform pattern of change in species richness was detected among the different taxonomic groups with increasing disturbance. Species richness of epiphytic bryophytes and vascular plants declined significantly from mature forest towards open vegetation. In contrast, species richness of epiphytic lichens did not change with increasing forest alteration, while that of geometrid moths was significantly higher in recovering forest compared with mature forest and open habitats. Arctiidae were significantly more species-rich in recovering forest and open vegetation than mature forest. Hence, for some organisms, modified habitats may play an important role for biodiversity conservation in the Andes, whereas others suffer from habitat disturbance. However, trends of changes in species composition following deforestation were surprisingly concordant across most studied epiphyte and moth taxa.  相似文献   

5.
1 We characterized and compared diversity patterns of canopy and understorey spiders (Arachnida: Araneae) on sugar maple ( Acer saccharum Marsh.) and American beech ( Fagus grandifolia Ehrh.) in hardwood forests of southern Québec, Canada.
2 We sampled canopies of 45 sugar maple and 45 American beech trees and associated understorey saplings in mature protected forests near Montréal. Samples were obtained by beating the crown foliage at various heights and by beating saplings around each tree.
3 Eighty-two species were identified from 13 669 individuals. Forty-eight species and 3860 individuals and 72 species and 9809 individuals were collected from the canopy and the understorey, respectively.
4 Multivariate analyses (NMDS ordination and NPMANOVA) showed the composition of canopy and understorey assemblages differed significantly, and canopy assemblages differed between tree species. Rank-abundance distribution models fitted to the canopy and understorey data indicated that different mechanisms structure the assemblages in both habitats. Three abundant spider species were significantly more common in the canopy; ten species were collected significantly more often in the understorey.
5 The forest canopy was shown to be an important reservoir for spider diversity in north-temperate forests.  相似文献   

6.
长白山针阔混交林不同演替阶段的昆虫多样性   总被引:6,自引:0,他引:6  
贾玉珍  赵秀海  孟庆繁 《昆虫学报》2009,52(11):1236-1243
昆虫多样性变化对生态系统健康有重要的指示作用, 为研究昆虫群落变化与生境演替之间的关系, 本研究采用网捕、灯诱和诱捕法系统调查了长白山针阔混交林不同演替阶段(次生白桦林、次生针阔混交林、原始阔叶红松林)昆虫群落的组成和多样性, 分析了昆虫在森林演替过程中的规律及与植被群落之间的关系。系统调查共采集昆虫标本8 183头, 隶属于14个目699种, 其中鳞翅目和鞘翅目是主要优势类群。次生针阔混交林昆虫的个体数量最多, 原始阔叶红松林中物种数最多。不同演替阶段昆虫群落的物种数和个体数差异不显著, 但次生针阔混交林、原始阔叶红松林的Fisher’s α指数显著高于次生白桦林。目水平上的昆虫多样性未表现出显著性差异. 昆虫多样性在森林演替过程中和草本植物多样性的变化趋势相同;由于食性和生境选择的不同, 森林演替过程中鳞翅目昆虫多样性逐渐升高, 而鞘翅目多样性逐渐降低。  相似文献   

7.
Aim Urbanization is associated with strong changes in biodiversity, but the diversity of plant and animal assemblages varies among urban habitats. We studied effects of urban habitats on the diversity of vascular plants and land snails in 32 large cities. Location Central Europe, Belgium and the Netherlands. Methods The species composition of all vascular plants that had not been planted by humans, and all land snails, was recorded in seven 1‐ha plots within each city. Each plot contained one urban habitat type representing a different disturbance regime: historical city square, boulevard, residential area with compact building pattern, residential area with open building pattern, park, early successional and mid‐successional site. For each plot, we obtained temperature and precipitation data. The effects of climate and habitat types on species composition were quantified using ordination methods with an adjusted variation partitioning algorithm. Differences in species composition among urban habitats were described using statistically determined diagnostic species, and differences in alpha, beta and gamma diversity were quantified. Results A total of 1196 plant and 87 snail species were recorded. Habitat type explained higher proportions of the total variation in both plant and snail species composition (11.2 and 8.2%, respectively) than did climate (4.6 and 6.3%). For both taxa, the main differences in species composition were observed between strongly urbanized sites in city centres and early successional and mid‐successional sites. For vascular plants, the number of species was lowest in city squares and boulevards, and highest at successional sites and in residential areas with compact building patterns. Beta diversity of vascular plants calculated for the same habitat types among cities was highest for squares and successional sites. The number of snail species was lowest in city squares and at early successional sites, and highest at mid‐successional sites. The highest beta diversity of snail assemblages among cities was observed within the city square and early successional habitat types, and the lowest within residential area habitat types. Main conclusions Urban habitats differ notably in the diversity of their vascular plant flora and land snail fauna. Understanding the habitat‐related biodiversity patterns in urbanized landscapes will allow projections of future impacts of urban land‐use changes on the biota.  相似文献   

8.
Aim This study investigates diversity patterns of vascular plants and plant‐feeding geometrid moths during montane rain forest regeneration in relation to the biogeographical and historical conditions of Mt Kilimanjaro. Location Investigations were undertaken on the south‐western slopes of Mt Kilimanjaro at altitudes between 2075 and 2265 m. Methods Thirteen plots were selected for this study. Four of these were situated in the middle of large clearings (> 1000 m2), three in secondary forest, two in mature forest remnants surrounded by secondary forest and four plots within continuous closed mature forest. Vascular plant species were recorded in an area of 20 × 20 m2. Geometrid moths were attracted using lamps placed inside reflective gauze cylinders. Results Ninety‐three species of vascular plants were recorded on the plots. Plant diversity increased in the course of forest regeneration from clearings and secondary forest to mature forest remnants and mature forest. This increase was visible in all vegetation strata as well as in the species number of Dicotyledoneae. The diversity of geometrid moths conversely decreased from early to late successional stages. A total of 2276 Geometridae representing 114 morphospecies were included in the study. Local values of Fisher's α varied from 10.3 to 18.3 on clearings and in secondary forest, whereas they remained below 8.0 in mature forest and mature forest remnants. There was a significant negative correlation between the diversity of Geometridae and the number of dicots, and of plant species in the shrub layer. Main conclusions Contrary to an expected positive correlation between the diversity of vascular plants and herbivorous geometrid moths, diversity patterns of these two groups are strongly diverging due to biogeographical and ecological factors differently affecting the two groups. The increase in plant diversity can chiefly be explained with an increase in epiphyte diversity which is related to the occurrence of suitable habitats in extensive moss layers on huge Ocotea usambarensis (Engl.) trees in the mature forest. The low diversity of geometrid moths in these forests may be connected to the isolation and relatively young age of the montane rain forests on Mt Kilimanjaro. Hence only a small number of moth species adapted to the cool and perhumid conditions within moist mature forest have so far immigrated into these habitats, and time was insufficient for the evolution of many new species.  相似文献   

9.
Male euglossine bees were sampled with chemical baits every two months from September 1997 to July 1999 at nine sites in the Desengano mountain range, Rio de Janeiro State, Brazil. Four sites were located in Atlantic Forest mature second growth, two sites in disturbed forest, and three sites in forest fragments of 200, 156, and 14 ha, respectively. We collected 3653 male euglossine bees from at least 21 species. Analyses of variance indicated no differences among the three habitat types for total number of bees, and 5 of the 6 dominant species. Bootstrapping indicated significant variation in species richness and diversity for some sites, but there was no clear indication of differences among habitats. Similarity as measured with the Morisita–Horn index was inversely related to distance between sites, but relatively high for most site combinations. These results suggest that the euglossine bee community in the three habitats was essentially the same. Although some species were associated with each habitat type, most appeared to respond to temporal local conditions. Our results do not support the hypothesis that forest fragmentation or habitat alteration reduces abundance and diversity of euglossine bees.  相似文献   

10.
The effects of selective logging on the diversity and species composition of moths were investigated by sampling from multiple sites in primary forest, both understorey and canopy, and logged forest at Danum Valley, Sabah, Malaysia. The diversity of individual sites was similar, although rarefied species richness of logged forest was 17% lower than for primary forest (understorey and canopy combined). There was significant heterogeneity in faunal composition and measures of similarity (NESS index) among primary forest understorey sites which may be as great as those between primary understorey and logged forest. The lowest similarity values were between primary forest understorey and canopy, indicating a distinct canopy fauna. A number of species encountered in the logged forest were confined to, or more abundant in, the canopy of primary forest. Approximately 10% of species were confined to primary forest across a range of species' abundances, suggesting this is a minimum estimate for the number of species lost following logging. The importance of accounting for heterogeneity within primary forest and sampling in the canopy when measuring the effects of disturbance on tropical forest communities are emphasized.  相似文献   

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