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1.
Several previous studies have attempted to correlate habitat complexity and reef fish species diversity. These studies have mostly examined natural reef systems, but results differed. To examine this relation, we built 1 m2 habitats with 20 replicates of five complexity levels from July to August 2001 in the northeastern Gulf of Mexico (n=100). In June and July 2002, we built new habitats using the 2001 design, but also added a sixth complexity level (n=120). In order of increasing complexity these included: cage, shell, cage-shell, block-shell, cage-block-shell, and shell-block-pyramid habitats. Most fish in both years were juveniles and included species common to reef structures in the northeastern Gulf of Mexico. In 2001, we identified 26 fish species, and the dominant species was red snapper, Lutjanus campechanus (41%), followed by rock sea bass, Centropristis philadelphica (23%), and sand perch, Diplectrum spp. (14%). In 2002 we identified 36 species, and the dominant species was tomtate, Haemulon aurolineatum (36%), followed by Diplectrum spp. (19%), and L. campechanus (13%). In 2001, species diversity and richness were significantly (P<0.05) higher on more complex habitats (H′=1.7, S=11–12) compared to less complex habitats (H′=0.8–1.0, S=4–9). In 2002, patterns among diversity, richness and reef complexity were less apparent with only the least complex habitats shell and cage showing significantly lower values. In both years, multidimensional scaling grouped by complexity levels with cage and shell habitats showing the clearest separation from other habitat types. Also, with few exceptions (only 8%) analysis of similarities showed significant (P<0.05) differences in fish communities across complexity levels. Although community composition varied between years, this study provided evidence to support the hypothesis that habitat complexity increased reef fish species diversity.  相似文献   

2.
武夷山自然保护区天蛾科昆虫多样性的初步研究   总被引:2,自引:0,他引:2  
通过2002年至2008年的陆续采集和2009年5月至10月定期系统调查采集,获得武夷山自然保护区的天蛾标本共2 103号,它们隶属于5亚科、33属、75种和亚种.该保护区天蛾科昆虫的区系成分以东洋区种类为主,其次是广布种,并且有少量的古北区种类及特有种;天蛾种类和个体数量的高峰期基本集中在6~8月,鹰翅天蛾Ambul...  相似文献   

3.
Kanazawa Castle Park (KCP) is an isolated urban green area in Kanazawa, Japan. A mature forest had developed there since 1949, but it was partially deforested from 1996 to 1999. Moreover, most of the grasslands in KCP were removed from 2000 to 2002. In this study, we report the damage to the butterfly assemblage by these anthropogenic disturbances and subsequent recovery after the disturbances, using previous literature on the butterfly assemblage in KCP from 1990 to 1994 and our monitoring data from 1999 to 2005. In addition, to understand urbanization effects, we also compared the butterfly assemblage of KCP with that of Tawara, a satoyama area 6 km away from KCP. Before the urbanization around KCP, KCP might have had a butterfly assemblage similar to Tawara. The previous articles indicate that 33 species lived in KCP before the partial deforestation. The number of generalist species (multivoltine and polyphagous species) was similar in KCP and Tawara (22 vs. 19), but that of specialist species (uni-bivoltine and oligophagous species) was lower in KCP than in Tawara (5 vs. 15). Six species, composed of a bamboo grass feeder, mantle feeders, herb/grass feeders, and a multi-feeder, disappeared from KCP after the deforestation and have not yet recolonized. The grassland removal also affected herb/grass feeders negatively, but they have been recovering quickly following the partial grassland recovery. Some species that disappeared after the deforestation were sporadically found from 2000 to 2005 probably due to immigration from the surrounding rural areas (the nearest one is 2 km away). For recolonization of the lost species, recovery of the interior and edge of the forest, which are the habitats for these species, is necessary.  相似文献   

4.
The marsh fritillary is widely distributed in Wales, with over 200 populations identified in the past 15 years. However, agricultural improvement, habitat fragmentation and changes in agricultural practices continue to impact on status and a decline in range of 23.5% was recorded over a 10-year period. Solutions must be applied at the landscape scale to improve metapopulation viability and, since 2000, surveys of habitat extent and quality have been carried out on 116,373 ha of grassland surrounding 111 populations. Analysis of the results for standard ‘core landscapes’ (based on circles of 1 km radius around known populations) shows that overall cover of suitable breeding habitat is 3.44%. However, only 11.85% of the grassland that was suitable for marsh fritillaries was classified as being in Good Condition. The remainder was regarded as having sub-optimal vegetation structure and/or the foodplant was at low density; 33% of the habitat resource that was not in Good Condition was regarded as inappropriately or excessively managed and 67% was suffering from neglect. An Index of Landscape Quality is used to rank landscapes for evaluation. Thirty-five ‘core landscapes’ (incorporating 98 marsh fritillary populations) were assessed and just four exceeded a threshold value deemed to represent viable landscape configurations. The results have demonstrated that most marsh fritillary populations in Wales exist within depauperate patch networks that lack sufficient breeding habitat of the right quality for long-term persistence. Without targeted conservation action the marsh fritillary will continue to decline in Wales. This paper reports on efforts to collect information on the quality of breeding habitat for marsh fritillaries across Wales in order to identify priorities for conservation action.  相似文献   

5.
An international project, DIWPA-IBOY, took place for simultaneously observing biodiversity throughout the Western-Pacific and Asian regions in 2001–2003, as one of the core projects for International Biodiversity Observation Year, a crosscutting network activity of DIVERSITAS (an international programme of biodiversity science). DIWPA-IBOY provides extensive data on species diversity obtained by the standardized method. Under this project, 51,742 individuals of Lepidoptera and 11,633 of Coleoptera were collected by light traps from the Tomakomai Experimental Forest of Hokkaido University, one of the core DIWPA-IBOY sites, in the cool-temperate region of northern Japan. Based on these data, this study examined the relative abundance distribution (RAD) to evaluate the amount of rare species in the Lepidoptera and Coleoptera communities. The beta diversities between sampling seasons, forest strata, and trap sites were also assessed to evaluate the spatio-temporal variability of species composition in these communities. In the analysis of the RAD, the best-fit model was selected from the log-Normal, Zipf–Mandelbrot, and Zipf models differing in the tail length of the RAD, i.e., the proportion of rare species. To explore the beta diversity between samples, the abundance-based Jaccard index with an unseen species estimator was calculated, and then a hierarchical clustering analysis was conducted. As a result of RAD analysis, the Coleoptera community was regarded as containing a larger proportion of rare species than the Lepidoptera community. The seasonal compartmentalization of the community, deduced from the beta-diversity analysis, was finer in Lepidoptera (seven assemblages recognized) than in Coleoptera (three assemblages). The spatial (vertical and horizontal) compartmentalization was negligible in both communities. The coincidence of the larger proportion of rare species and the lower beta diversity between seasons in the Coleoptera community was explained by the longer life spans of beetles compared to moths, based on the assumption that the length of life span acts as a temporal agent for mass effect on the analogy of the migration rate as a spatial agent for mass effect.  相似文献   

6.
7.
Definition of northern British grassland Auchenorrhyncha habitats was carried out using a classification based on analysis of data from 351 sites, involving 121 species, located between Greater Manchester and northern Scotland. Ten habitats were identified showing little influence of geographical position and exhibiting a basic upland-lowland trend. Other factors influencing habitat and species assemblage distribution were soil water, vegetation structure and land cover. An analysis of the species data with satellite-derived land cover data indicated that the lowland covers of tilled land, coast and urban and the upland covers of heath grassland and shrub heath were most important in affecting both species and assemblage distribution. The large-scale survey of grassland sites provided new information on both the ecology and distribution of individual Auchenorrhyncha species. Some were limited to specific habitat types but a considerable number were generalist species found in most or all of the 10 habitat types but showing preferences within upland to lowland or wet to dry site gradients. The ability to generate a subtle grassland Auchenorrhyncha habitat classification with large-scale survey results from standardised and reproducible sampling increases the potential for using habitat diversity for the conservation of grassland Auchenorrhyncha. Habitat preservation would also ensure that species richness (biodiversity) is maintained and that the habitats of rare species are conserved.  相似文献   

8.
Most studies linking dietary variation with insect fitness focus on a single dietary component and late larval growth. We examined the effects of variation in multiple dietary factors over most life stages of the sphingid moth, Manduca sexta. Larvae received artificial diets in which protein, sucrose, and water content were varied. The relationship between larval size, growth and consumption rates differed significantly across diets. Larvae on control and low-sucrose diets grew most rapidly and attained the largest pupal and adult sizes. Conversely, larvae on low-water and low-protein diets initially grew slowly, but accelerated in the fifth instar and became pupae and adults comparable to control animals in size. There were no fundamental differences in protein:carbohydrate consumption patterns or strategies among experimental diets and larval instars. However, inadequate dietary water appeared to be more important for early than late instar larvae. Larvae on all artificial diets showed increasing fat content throughout all stages, including wandering and metamorphosis. Compensatory feeding among low-water and low-protein larvae was correlated with significantly higher fat content in larvae, pupae and adults, whereas low-sucrose animals were substantially leaner than those on the control diet. These differences may have strong effects on adult physiology, reproduction, and foraging patterns.  相似文献   

9.
Summary We studied the reproductive ecology of a population of Sceloporus undulatus erythrocheilus near Walsenburg, CO during the summers of 1987–1990. Reproductive activity commences soon after emergence in early May and continues until the middle of July. Females mature in their second year following hatching at an age of 20–21 months and a size of 60–63 mm snout-vent length (SVL). Two clutches, averaging10.9 eggs, are produced per year. Larger females produce larger clutches with an increase of one egg per 3 mm SVL. Average SVL of females was 71 mm. Eggs are reasonably large (0.32 g) and relative clutch mass was the largest reported for the species (34% of body mass). A principal component analysis was used to examine relationships among reproductive characters in 12 populations of Sceloporus undulatus. The analysis suggested that patterns of reproduction in this wide-ranging species result from several factors reflecting both adaptive and phylogenetic sources of variation.  相似文献   

10.
Abstract.
  • 1 Wing form frequencies in 255 populations of 101 species of leafhoppers (Auchenorrhyncha) in temporary and permanent habitats were documented.
  • 2 The proportion of brachypterous specimens in the leafhopper assemblages on ruderal host plants in temporary habitats (median 2%, range 0–8%) was significantly lower than that on permanent host plants in undisturbed habitats (median 22%, range 0–94%).
  • 3 Leafhopper species typical of temporary habitats were either monomorphic, macropterous, or wing-dimorphic with macropterous forms prevailing in both sexes.
  • 4 Among the eighty-nine species recorded in permanent habitats, forty-five species were wing dimorphic. In forty-one dimorphic species, a brachypterous form prevailed. This prevalence was found for both sexes in thirty-one species, for only females in nine species and for only males in one species.
  • 5 The prevalence of brachypters in males, but not in females, found in Anoscopus flavostriatus, is probably the first such documented case in Auchenorrhyncha.
  • 6 The hypothesis is proposed that in temporary habitats, density-dependent production of macropters in wing dimorphic species is an adaptation to frequent habitat deterioration caused by factors independent of the density of the species.
  • 7 The predominance of brachypters in permanent habitats indicates that a density-dependent decrease in fitness usually does not offset the potential decrease in fitness connected with macroptery and dispersal. Because of this inability of leafhopper populations to decrease significantly the quality of their resources, a high population density cannot be used as a predictor of future quality of these resources, which is information essential for efficient dispersal behaviour.
  相似文献   

11.
The role of the maxillary muscles in the uncoiling and coiling movements of hawkmoths (Sphingidae) has been examined by electromyogram recordings, combined with video analysis. The maxillary muscles of adult Lepidoptera can be divided into two groups, galeal and stipital muscles. The galea contains two basal muscles and two series of oblique longitudinal muscles, which run through the entire length of the galea. Three muscles insert on the stipes, taking their origin on the tentorium and on parts of the cranium and gena, respectively. Proboscis extension is initiated by an elevation of the galea base caused by the basal galeal muscles. The actual uncoiling of the proboscis spiral is accompanied by rapid compressions of the stipites which are caused by two of the stipital muscles. The study provides strong support for the hypothesis that uncoiling is brought about by an increase of hemolymph pressure by the stipites forcing hemolymph into the galeae. Recoiling is caused by the contraction of both sets of oblique longitudinal galeal muscles supported by elasticity of the galea cuticle. Finally, the remaining stipital muscle pulls down the galea base which brings the coiled proboscis back to its resting position where it is held in the U-shaped groove of the labium without further muscle activity.  相似文献   

12.
To be able to deseribe the structure and functioning of Miscanthus sinensis grassland, its floristie composition, life-form spectra, stand productivity and dry matter allocation were studied. 43 species were to be found during the growing season of 1976. 29 species, and 345 individuals per 1 m2, were observed in the sample areas in September. The values for standing crop of constituent species have been arranged in ascending order. The dominant Raunkiaer life-forms were the hemicryptophyte and geophyte. The stand was characterized by erect and tufted forms in Numata's system of growth form classification. The standing crop of the whole stand decreased from April to June, then increased from mid-July. The maximum standing crop of 3346 g m-2was observed in September. The net production of the stand was 959.4 g m-2year-1. Fifty one percent of this net production was allocated to the underground organs which consume it for respiration during winter and for initial growth in the next growing season.  相似文献   

13.
Ideal preemption and conspecific attraction are alternative hypotheses of the habitat selection rules used by individuals. According to the former an occupied site is assumed to be preempted and therefore not available for later arriving individuals, whereas according to the latter individuals are assumed to be attracted by conspecifics to occupied sites, rather than avoiding them. We studied these competing hypotheses in breeding mallards (Anas platyrhynchos) by a cross-over experiment in 2 years, introducing birds onto lakes before migratory wild mallards arrived. If mallards use the ideal preemptive rule, breeding density of wild mallards in experimental lakes should be lower and they should be occupied less frequently than control lakes, but if mallards use the conspecific attraction rule the reverse should be true. Our results allowed us to reject the ideal preemptive rule whereas the conspecific attraction rule was to some extent supported. We discuss these findings in relation to population limitation. The results suggest that the local breeding population studied is not limited by spacing behaviour related to habitat selection. Received: 14 July 1997 / Accepted: 17 November 1997  相似文献   

14.
M. G. McManus  J. Travis 《Oecologia》1998,114(3):317-325
While the life history traits of animals usually exhibit substantial phenotypic plasticity, such plasticity might reflect either a simple alteration in the level of energy accrual and use or a genuine shift in energy allocation tactics between environmental conditions. The latter would represent genuine plasticity in the life history itself, and thus it is important to distinguish which of these two processes underlies the observed plasticity of life history traits. We investigated this issue by examining the effects of temperature and salinity variation during ontogeny on the allocation of biomass and lipid storage in male sailfin mollies, Poecilia latipinna. We raised males from four natural populations from birth to maturity in controlled laboratory conditions. Neither distinct temperatures (23 or 29°C) nor different salinity regimes (2, 12, or 20 parts per thousand) affected body mass, although males from different populations differed substantially in body mass. However, males raised at the higher temperature had a greater allocation of biomass to testis and a lower allocation to viscera mass. The amount of stored lipid was altered by temperature variation but the direction and magnitude of the effect varied substantially among males from the different populations. Salinity variation affected neither biomass allocation nor the level of lipid storage. These results indicate that male mollies possess a flexible developmental program with respect to temperature that canalizes body size and alters the allocation of biomass among competing demands for reproductive readiness and capacity for energy storage. Received: 25 November 1996 / Accepted: 1 December 1997  相似文献   

15.
An ecological study was conducted in May and June of 1995 and 1996 in South Carolina to determine the factors associated with distributions of aquatic Lepidoptera (Crambidae: Nymphulinae). Larvae were found at 65 lotic and lentic sites in three ecoregions (Piedmont, Sandhills, Coastal Plain). Nine species of aquatic Lepidoptera were collected from 12 species of aquatic vascular macrophytes. One to six plant species were used as hosts, depending on the species of lepidopteran; however, the number of host plants used by a lepidopteran was significantly correlated with the lepidopteran's frequency of occurrence. Significant habitat associations were found for five species. Langessa nomophilalis (Dyar) was found under the widest range of temperature and width and occurred in both lotic and lentic habitats. Munroessa icciusalis (Walker) was found in lotic and lentic habitats and had the widest range of recorded depths. Parapoynx maculalis (Clemens) occurred at stream sites with lentic-like conditions. Parapoynx obscuralis (Grote) occupied the widest range of pH and was restricted to lotic habitats, and P. seminealis (Walker) was found in both lotic and lentic habitats. Additional species, collected at fewer than 8% of sites, included M. gyralis, P. allionealis, Synclita obliteralis, and S. tinealis. Overall, the distributions of aquatic Lepidoptera in South Carolina were nonrandom and predictable on the basis of habitat characteristics. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

16.
Key mortality factors due to natural biological control of the melonworm, Diaphania hyalinata, were investigated. Mortality factors were quantified in cucumber plots and used to develop a life table. The highest mortality of the melonworm took place during the egg stage (90.08% mortality) when the most important mortality factor was the predator Paratrechina sp. (Hymenoptera: Formicidae). However, the critical mortality stage of this insect pest was the fifth larval instar and its key mortality factor was parasitism by tachinid flies (aff. Amazohoughia, Eucelatoria sp. and aff. Lixophaga).  相似文献   

17.
A survey was conducted on the species composition, richness and abundance of Papilionoidea (excluding Lycaenidae) butterfly fauna in habitats with various degrees of disturbance and altitudes in tropical forests at Tam Dao National Park, northern Vietnam in 2001. The transect method was used to collect data in the survey. Six transects representing different habitat types at two sites, one site located at a low elevation of 200–250 m a.s.l., and the other located at a high elevation of 950–1000 m a.s.l., were chosen: three transects for each site, with a length of 500 m for each transect. A total of 3594 individuals of 127 species in 240 sets of data were recorded from various habitats. The differences in butterfly composition, species richness, abundance and diversity in different habitat types and altitudes were analyzed. The results showed significant differences of butterfly diversity among the different habitat types and between the low and high altitude sites. The butterfly diversity, species richness and species abundance in the low elevation habitats were higher than in the high elevation habitats. The highest diversity of butterflies occurred in the mixed habitats of agriculture, scrub and clearing lands of high disturbance. However, butterflies most important for conservation are associated with undisturbed or moderately disturbed forests only.  相似文献   

18.
Newell  Graeme R. 《Plant Ecology》1998,137(1):55-70
Phytophthora cinnamomi (cinnamon fungus) is a pathogenic soil fungus which infects plant communities such as open forests, woodlands and heathlands in the south-eastern and south-western corners of Australia, leading to devastating effects upon both structural and floristic features of these plant communities. This study undertaken in open forest in the Brisbane Ranges, south-eastern Australia, sought to characterize two study areas using visual classification and several ordination techniques. Additionally, sites were examined for differences in vegetation composition relating to P. cinnamomi infection, and how these may relate to site habitat quality for resident fauna. This characterization had a high degree of conformity (90% to 96%) between the original visual classification and several ordination methods used. Differences in the cover of understorey vegetation including both low and tall shrubs, and the grass-tree Xanthorrhoea australis were recorded between uninfected and post-infected sites, however the cover of litter or bare ground did not infer infection status. There were no consistent significant differences in projective crown cover of Eucalyptus spp. between uninfected and infected sites, nor in the number of hollows suitable for den or nest sites for arboreal mammals and birds. Hence, the impact of P. cinnamomi upon faunal habitat quality at the sites was considered more likely to relate to changes in ground level vegetation structure than to effects of the pathogen on the dominant Eucalyptus species. Based on the small proportion of sites with detectable isolates of the pathogen (25%), and the slow rate of movement of the disease front during this study (1 to 5 m/3 yr), the current state of disease progression appeared relatively quiescent compared to infestations previously documented in the same area a decade or two earlier.  相似文献   

19.
The life history of the mistletoe-feeding butterfly Ogyris amaryllis is commonly thought to involve an obligate association with ants. The distribution of eggs of subspecies O. a. meridionalis Bethune-Baker, which occurs over much of the Australian interior, is strongly associated with Iridomyrmex ants. This study examined the level and frequency of ant association exhibited by larvae and pupae of O. a. amaryllis , which occurs in coastal areas of eastern Australia. The distribution of juveniles was compared with that of ants at the scale of sites, mistletoe host trees, and larval sheltering locations. A significant positive association between larvae and ants was detected, although this association was weak and non-specific, indicating that O. a. amaryllis is facultatively myrmecophilous. Observed ant attendance of larvae was uncommon (5.6%). Available evidence suggests that either plasticity exists in the degree of myrmecophily of O. amaryllis , with different degrees of association expressed under different ecological circumstances, or different degrees of myrmecophily are characteristic of subspecific status.  相似文献   

20.
永泰青云山风景区蝶类多样性研究   总被引:1,自引:0,他引:1  
本文应用Shannon - -Wiener多样性指数 ,均匀度 ,优势度指数指标 ,分析青云山风景区不同耕作类型蝶类的多样性。结果表明 :青云山蝶类多样性较高 ,种类较丰富。耕作类型蝶类多样性指数变化趋势为 :森林类型〉栽培景观类型 ;耕作分类型蝶类多样性指数变化趋势为 :阔叶林〉针叶林〉果园〉竹林〉菜地〉田地。蝶类多样性指数不受均匀度影响 ,但受季节影响明显  相似文献   

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