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1.
Intertidal zonation and seasonality of tropical meiobenthic communities were examined within five mangrove estuaries along the northeastern coast (Cape York peninsula) of Australia from May 1985 to January 1986. Partial correlation analysis revealed that environmental cues such as temperature and sediment granulometry were the most important factors regulating the zonation patterns of meiofauna. Seasonality was greatly influenced by monsoonal rains. During austral summer, prolonged monsoonal rains occurred along the coast north of 18°S latitude (Hinchinbrook Island), resulting in increased river discharge and scouring of surface silts and clays, organic matter and bacteria from most tidal sediments. Despite scouring, meiofaunal densities increased in the summer wet season, probably due to warmer temperatures and the high resilience of meiobenthos to sediment disturbance. In mangrove sediments not subjected to torrential rains (Hinchinbrook Island), meiofaunal densities were highest in austral autumn and winter (sediment temperature: 23 to 27°C) and lowest in austral spring and summer (28° to 40°C). Turbellarians were the dominant meiofaunal group, accounting for 58 to 67% of total faunal densities which generally decreased with elevation in all of the estuaries. Meiofauna in tropical Australian mangroves, as in other organic-rich muds and in coral reefs, appear to exert little impact on microbial standing stocks when intercorrelated variables are accounted for. The abundances of hard-bodied meiofauna were low compared with temperate communities, lending further support to Moore's (1972) contention that tropical intertidal communities are subjected to greater physical stress than their temperate counterparts.  相似文献   

2.

Goal, Scope, and Background

Soil organisms play a crucial role in the terrestrial ecosystem. Plant Protection Products (PPPs) are known to affect soil organisms and might have negative impacts on soil functions influenced by these organisms. Little research has been done to day on the impact of PPs on tropical ecosystems. Therefore, in this study it was investigated whether fate and effects of pesticides differ between tropical and temperate regions and whether data generated under temperate conditions can be used for the Environmental Risk Assessment (ERA) in tropical regions.

Methods

In the first part of this study, the effects of two fungicides (Benomyl and Carbendazim) and one insecticide (lambda-Cyhalothrin) on soil invertebrates (i.e. earthworms and arthropods) were evaluated in laboratory tests modified for tropical conditions (temperature, soil, test species). Besides using some native species, the tests were done mainly with two (temperate and tropical) strains of earthworms (Eisenia fetida) and the peregrine isopod speciesPorcellionides pruinosus as standard test species. The chemicals were spiked in two natural and two artificial soils. A tropical artificial soil (TAS), containing a tropical fern product (Xaxim) or coconut coir dust as organic matter, was developed in this study.

Results and Conclusions

The results from the laboratory tests showed that all three test chemicals differed from those gained under temperate conditions. In the case of the fungicides the toxicity was lower but in the case of the insecticide higher under tropical than under temperate conditions. The native tropical earthwormPontoscolex corethrurus reacted more sensitively against Carbendazim in comparison to the standard test speciesEisenia fetida.

Recommendation and Perspective

Details of the environmental risk assessment of the three model chemicals based on the results of the laboratory described here (and including the results of higher tier tests (semi-field and field tests)) will be described in Part 2 of this series  相似文献   

3.
Structural variations in the shell of the tropical limpet Cellana radiata (Born) inhabiting the high and low water zones and the exposed and protected surfaces at Palm Beach, Waltair Coast, India, were investigated. Attempts have also been made to study which environmental factors have a marked influence upon the characters of the shell. The results are discussed and are compared with those on temperate climate limpets.  相似文献   

4.
Algar AC  Kerr JT  Currie DJ 《Ecology》2011,92(4):903-914
The influence of regional and local processes on community structure is a major focus of ecology. Classically, ecologists have used local-regional richness regressions to evaluate the role of local and regional processes in determining community structure, an approach that has numerous flaws. Here, we implemented a novel trait-based approach that treats local and regional influences as a continuum, rather than a dichotomy. Using hylid frogs (Hylidae), we compared trait dispersion among members of local species assemblages to the trait dispersion in the regional assemblage from which they were drawn. Similarly, we compared trait dispersion in the regional assemblages to dispersion in the continental species pool. We estimated the contributions of local and regional filters, and we compared their strength in temperate and tropical zones. We found that regional and local filters explained 80% of the total variation among local assemblages in community body size dispersion. Overall, regional filters reduced trait dispersion, and local filters increased it, a pattern driven by particularly strong antagonistic effects in temperate zones that reduced the realized total variation by more than 40%. In contrast, local and regional filters acted in concert in tropical regions. Patterns within the tropics did not differ from the random expectation based on a null model, but within the temperate zone, local community filtering was stronger than expected by chance. Furthermore, in temperate regions, antagonistic regional and local filtering masked from 76% to 90% of the total variation in trait dispersion. Together, these results suggest that there are fundamental differences in the scale and identity of the processes determining community structure in temperate and tropical regions.  相似文献   

5.

Goal, Scope, and Background

Soil organisms play a crucial role in terrestrial ecosystems. Plant Protection Products (PPPs) are known to affect these organisms and might have negative impacts on soil functions influenced by these organisms. Little research has been done to day on the impact of PPPs on tropical ecosystems. Therefore, in this study it was investigated whether the effects of pesticides differ between tropical and temperate regions and whether data generated under temperate conditions can be used for the Environmental Risk Assessment (ERA) in tropical regions.

Methods

The effects of one fungicide (Carbendazim) and one insecticide (lambda-Cyhalothrin) on soil invertebrates (earthworms and arthropods) and functional parameters (organic matter (OM) breakdown, feeding rate) were evaluated in semi-field tests using Terrestrial Model Ecosystems (TMEs) and in field tests using litter-bags. The soil for the TMEs was extracted from the same site near Manaus (Amazonas, Brazil) where the field test was conducted (see Part 1, Römbke et al. 2005 〈DOI: http://dx.doi.org/10.1065/uswf2004.12.088.1〉). The soil was acid clay, typical for tropical regions. In the TMEs the standard test species as well as native tropical species were introduced. Several application scenarios, selected according to their relevance for practical conditions, were realized in TME-tests and field (duration: 150 and 365 days, respectively). Finally, an Environmental Risk Assessment (ERA) for the two chemicals was performed.

Results and Conclusions

The results from the TME-tests show that both test chemicals (depending on their concentration) had toxic effects on the tested organisms and organic matter breakdown, but not on the feeding rates. In the field organic matter breakdown was affected for some time too, but effects on single species were, with one exception (the native earthworm Andiorrhinus amazonicus) not observed; a result probably influenced by the small size of the test plots. Observed differences in OM breakdown between control and treated TMEs were often significant, while due to the higher variability even with differences >10% between means this was not the case in the field.

Recommendation and Perspective

According to the preliminary results of the Environmental Risk, Assessment presented here, the use of the three model chemicals in the tropics (e.g. in Brazil) can cause a damage to the environmental compartment soil. Therefore, a more detailed investigation of these PPPs is recommended, in particular a better evaluation of the exposure (residue analysis). In general, the work performed in Amazonia can be summarised as follows: (1) Depending on the properties of the PPP, the effects of pesticides in tropical resp, temperate regions can differ. (2) If a PPP is going to be used in the tropics, data from tests modified for these conditions should be performed and their results should be incorporated in an Environmental Risk Assessment (ERA) for tropical regions.  相似文献   

6.
Mangan SA  Herre EA  Bever JD 《Ecology》2010,91(9):2594-2603
A growing body of evidence obtained largely from temperate grassland studies suggests that feedbacks occurring between plants and their associated soil biota are important to plant community assemblage. However, few studies have examined the importance of soil organisms in driving plant-soil feedbacks in forested systems. In a tropical forest in central Panama, we examined whether interactions between tree seedlings and their associated arbuscular mycorrhizal fungi (AMF) lead to plant-soil feedback. Specifically, do tropical seedlings modify their own AMF communities in a manner that either favors or inhibits the next cohort of conspecific seedlings (i.e., positive or negative feedback, respectively)? Seedlings of two shade-tolerant tree species (Eugenia nesiotica, Virola surinamensis) and two pioneer tree species (Luehea seemannii, Apeiba aspera) were grown in pots containing identical AMF communities composed of equal amounts of inoculum of six co-occurring AMF species. The different AMF-host combinations were all exposed to two light levels. Under low light (2% PAR), only two of the six AMF species sporulated, and we found that host identity did not influence composition of AMF spore communities. However, relative abundances of three of the four AMF species that produced spores were influenced by host identity when grown under high light (20% PAR). Furthermore, spores of one of the AMF species, Glomus geosporum, were common in soils of Luehea and Eugenia but absent in soils of Apeiba and Virola. We then conducted a reciprocal experiment to test whether AMF communities previously modified by Luehea and Apeiba differentially affected the growth of conspecific and heterospecific seedlings. Luehea seedling growth did not differ between soils containing AMF communities modified by Luehea and Apeiba. However, Apeiba seedlings were significantly larger when grown with Apeiba-modified AMF communities, as compared to Apeiba seedlings grown with Luehea-modifed AMF communities. Our experiments suggest that interactions between tropical trees and their associated AMF are species-specific and that these interactions may shape both tree and AMF communities through plant-soil feedback.  相似文献   

7.
探索植物区系过渡性的地理分布格局,对于理解植物区系的起源、迁移和分布具有重要意义。本研究利用620个植物群落样方,探讨了云南地区植物区系过渡性的地理分布格局及其生物地理意义。研究结果表明,随着纬度、海拔的升高,温带区系成分所占比重呈显著递增趋势,但在经度梯度上呈递减趋势;热带区系成分所占的比重在地理梯度上则表现为相反的变化趋势。地形格局较好地反映了区系成分的地理分布格局;热带区系成分所占比重与温带区系成分所占比重的比值从南到北呈递减趋势。区系过渡性的低值主要出现在滇西北地区和包括滇西南、滇东南与滇南在内的云南南部地区,而高值主要出现在云南中部地区和中海拔地区,这可能与区系迁移过程和海拔梯度有关。热带区系成分在云南地区基带植被中占主导地位;热带区系成分占优势地位的区域主要集中在低海拔地区,占云南土地面积的60%左右,而温带区系成分占优势地位的区域主要集中在高海拔的北部地区,占土地总面积的40%左右。本研究从基带植被的区系性质和温、热带植物区系成分占优势地位的土地面积的构成证实了云南地区可能是一个“热带山原”的假说。区系过渡性随着年平均温度的升高,呈先增强后减弱的单峰格局。当年均温在13.1℃左右时,出现区系平衡点。相对水平分布而言,云南地区植被的垂直分布可能更值得注意。  相似文献   

8.
A. Sournia 《Marine Biology》1969,3(4):287-303
In this review, tropical seas are limited geographically by a minimum surface temperature of 22°C throughout the year. The relevant literature consists of nearly a hundred references, corresponding to about 45 stations or areas; most of these are neritic or subject to land mass or island mass effects; few studies have been made in both oceanic and neritic waters of the Pacific Ocean. In neritic waters, as a rule, an annual cycle of species composition and intensity of primary production is observed: seasonal variations are related to hydrography (currents, upwelling) or climate (winds, rains, monsoons); some cases reported are doubtful due to insufficient or only qualitative data; so far, not a single example can serve as a proof for the absence of an annual cycle. Oceanic data are much too meagre to allow a generalization to be drawn; seasonal, hydrographic, and climatic changes must often also be taken into account; in regions of permanent stratification, productivity can be expected to remain at a low and continuous level throughout the year, but direct evidence of this is still lacking. In temperate and cold waters, seasons are of world-wide significance due to changes in the relation between euphotic and mixing layers' depths, i.e., in availability of light and nutrients for phytoplankton growth; thus general models of annual cycles can be described. In tropical seas, on the other hand, seasons are only regional and ecological factors can act in opposite ways according to time and space, so that no world-wide picture can be worked out.  相似文献   

9.
Thermodynamics is a powerful tool for the study of system development and has the potential to be applied to studies of ecological complexity. Here, we develop a set of thermodynamic indicators including energy capture and energy dissipation to quantify plant community self-organization. The study ecosystems included a tropical seasonal rainforest, an artificial tropical rainforest, a rubber plantation, and two Chromolaena odorata (L.) R.M. King & H. Robinson communities aged 13 years and 1 year. The communities represent a complexity transect from primary vegetation, to transitional community, economic plantation, and fallows and are typical for Xishuangbanna, southwestern China. The indicators of ecosystem self-organization are sensitive to plant community type and seasonality, and demonstrate that the tropical seasonal rainforest is highly self-organized and plays an important role in local environmental stability via the land surface thermal regulation. The rubber plantation is at a very low level of self-organization as quantified by the thermodynamic indicators, especially during the dry season. The expansion of the area of rubber plantation and shrinkage of tropical seasonal rainforest would likely induce local surface warming and a larger daily temperature range.  相似文献   

10.
There is global concern about tropical forest degradation, in part, because of the associated loss of biodiversity. Communities and indigenous people play a fundamental role in tropical forest management and are often efficient at preventing forest degradation. However, monitoring changes in biodiversity due to degradation, especially at a scale appropriate to local tropical forest management, is plagued by difficulties, including the need for expert training, inconsistencies across observers, and lack of baseline or reference data. We used a new biodiversity remote‐sensing technology, the recording of soundscapes, to test whether the acoustic saturation of a tropical forest in Papua New Guinea decreases as land‐use intensity by the communities that manage the forest increases. We sampled soundscapes continuously for 24 hours at 34 sites in different land‐use zones of 3 communities. Land‐use zones where forest cover was fully retained had significantly higher soundscape saturation during peak acoustic activity times (i.e., dawn and dusk chorus) compared with land‐use types with fragmented forest cover. We conclude that, in Papua New Guinea, the relatively simple measure of soundscape saturation may provide a cheap, objective, reproducible, and effective tool for monitoring tropical forest deviation from an intact state, particularly if it is used to detect the presence of intact dawn and dusk choruses.  相似文献   

11.
New, large-scale collections have been made of marine benthic macroalgae (seaweeds) on the east coast of South Africa, and the distributions of shallow-water species were analyzed in detail by multivariate, clustering and -diversity methods. The two northernmost sites are distinct, with a predominance of tropical species, and it is concluded that the changeover from a tropical Indian Ocean flora to a temperate South African flora occurs most rapidly in the vicinity of St. Lucia, 135 km south of the Mozambique border. It is imperative that all future biogeographical studies on the South African inshore marine biota include detailed collections north of St. Lucia. The remaining 440 km of the South African east coast (southern and central Kwazulu-Natal Province) is populated by a mixture of tropical and temperate elements, with only 2% endemism in this data set. This, thus, represents a true overlap region, with relatively equal numbers of species with affinities in the temperate Agulhas and tropical Indo–West Pacific floras, rather than a distinctive sub-tropical marine province, as the South African east coast is considered to be by most previous authors. The distinction between this overlap region and the south coast (Agulhas) region proper is not as clearly distinct. The change from a temperate to a tropical flora shows a relative increase in green algae from 15% to 25% of the species present. Criteria for the delineation of marine biogeographical regions are critically discussed, and it is concluded that the monitoring of distributions of all species, including rare species, is necessary. This is particularly relevant with regard to using these data to assess effects of potential changes in seawater temperature, including those which may be caused by global warming. Criteria for the delimitation of biogeographic entities such as "marine provinces" need to be clearly spelt out in all investigations.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   

12.
G. J. Vermeij 《Marine Biology》1992,112(2):343-348
Several marine genera and species occur in the shallow-water temperate biotas of Europe and southern Africa, but not in tropical West Africa. Studies of the fossil record show that these trans-equatorial distributions were achieved before the Late Pliocene rather than during glacial episodes of the Pleistocene. Species of North Pacific origin entered the northeastern Atlantic at the beginning of Middle Pliocene time, and many penetrated to warm-temperate coasts of the Mediterranean and northwestern Africa. The fact that no Pacific-derived shallow-water molluscs and only one Pacific-derived algal genus (Laminaria) reached southern Africa without human agency suggests that trans-equatorial interchange was infrequent after the opening of Bering Strait during the Middle Pliocene, about 3.5 million years ago. The West African tropical zone must have remained wide enough or warm enough from the Late Pliocene onward to have acted as an effective barrier in which temperate species were unable to survive even during glacial times.  相似文献   

13.
Data on isopods processed by the author and the literature available on the subject have made it possible to provide specific lists of isopods for coastal zones of cold and cold-temperate regions in both hemispheres and for isopods from depths of more than 2000 m for the entire World Ocean. A comparative analysis shows both faunas to be very similar with respect to family and genus; in this respect they differ considerably from the shallow-water fauna of warm zones. Comparative-anatomic data indicate that the suborder Flabellifera is the most primitive, the Asellota the most specialized group; the data permit the singling out of the more primitive as well as the more specialized families in each suborder under study. Analysis of vertical distributions of all isopods in the World Ocean suggests that primitive isopods are principally confined to tropical shelves; however, in the shelves of cold and cold-temperate waters, especially in deep seas, a considerable number of phylogenetically recent families is present. Thus, the tropical shallow-water fauna proves to be the most ancient, while the shallow fauna of cold and temperate waters may be regarded as geologically more recent. The deep-sea fauna is considered to be the youngest. The author hypothesizes the probable ascendance of the deep-sea fauna from the Antarctic fauna in the period of increasing cold, as early as the late Cretaceous period. This process was promoted by glaciation in the Antarctic Ocean, and its gradual isostatic dipping together with the shelf.  相似文献   

14.
Eleven populations of the Pan-American sandy beach isopod Excirolana braziliensis, distributed from tropical (9°N) to temperate (39°S) sandy beaches in Atlantic and Pacific Oceans, were analyzed to determine latitudinal variations in: breeding and recruitment patterns, sex ratios, size of ovigerous females and of juveniles and length–fecundity relationships. E. braziliensis exhibited strong latitudinal patterns in all reproductive traits throughout its distribution range. Breeding and recruitment shifted from continuous to seasonal from tropical to temperate beaches, having a predominance of females at higher latitudes. In agreement with the latitudinal gradient hypothesis, ovigerous females inhabiting tropical sandy beaches (low latitudes) were smaller, became sexually mature at smaller sizes and had lower individual fecundity than on temperate beaches. Juveniles were also smallest at low latitudes. Between-ocean comparisons showed very similar reproductive characteristics for roughly the same latitude. These linked reproductive parameters suggest that the intensity of breeding effort is associated with the duration of the breeding season and geographically size-related characteristics of the species. Geographic variations in the breeding and recruitment seasons, as well as in individual fecundity, size structure of mature females and sex ratios, are proposed to have major consequences in explaining local variations in population demography. Our paper also reinforces the notion that sandy beach animals are highly plastic.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   

15.
Some aspects of the habitat zones, distribution pattern, and population density with reference to tidal levels of the tropical limpet Cellana radiata (Born) are presented. Observations have also been made on the homing behaviour of the limpet. Unlike the temperate limpets, no migration to different tidal levels during different seasons was observed in C. radiata.  相似文献   

16.
In most protected areas of the Indian Himalayan region site/habitat characteristics, community diversity and distribution pattern, vegetation composition (richness of native and endemic species), structural patterns, economic importance of forest communities and community priorities have rarely been studied. Therefore, the present study has focused on these in the buffer zone of Nanda Devi Biosphere Reserve. Seventy-six woody species (trees: 24; shrubs: 52) and 13 forest communities have been recorded between 2300–3800 m asl. Tree density ranged from 533–1220 ind ha-1, tree basal area from 14.68-80.28 m2ha-1 and shrub density from 1490–6695 ind ha-1. Mean density of trees was significantly lower in temperate forests in comparison to subalpine forests. Richness of trees ranged from 3–18 and shrubs from 5–29. Species diversity (H') of trees ranged from 0.45-2.08 and shrubs from 0.90-3.14. In the temperate zone, species richness and altitude had significant positive correlations whereas in the subalpine zone the two variables were negatively correlated. The native species were high in the area (> 65% species) and in communities (> 70% species), and was highest for the Picea smithiana-Pinus wallichiana mixed community, whereas the maximum numbers of natives and endemic species were recorded in the Pinus wallichiana community. The density and richness of non-natives were found to be significantly lower in comparison to the natives. Economic importance and conservation value of the communities were assessed and communities prioritized. Monitoring of the identified habitats, species, populations and communities, and development of appropriate strategies for their conservation and management are suggested.  相似文献   

17.
Data on biological productivity of the Western tropical Pacific Ocean   总被引:1,自引:0,他引:1  
Vertical distribution and production of phytoplankton and planktonic bacteria were studied in the pelagic and neritic regions of the Western tropical Pacific Ocean and in temperate waters of the Japan Sea. The stable, layering structure of the community and its daily fluctuations caused by grazing are described. Data on the integral daily production of communities under 1 m2 are presented. The data obtained are discussed with respect to the trophical relations in planktonic communities of the stratified sea basins.  相似文献   

18.
To estimate biomass and production, the cell volume of tintinnine ciliates has been assumed to be 50% of lorica volume. This assumption was tested using a high-precision digitizing system which measured individuals of 17 tintinnine species in samples taken in two annual studies of biomass and production in both tropical (Kingston, Jamaica in 1986) and temperate (Passamaquoddy Bay, Canada in 1983–1984) regions. Using this assumption, percent occupancies and hence, biovolume estimates, were overestimated by as much as 317% for tropical species and 178% for temperate species. Daily production estimates of the tropical tintinnine assemblage were overestimated by as much as 147%. In studies attempting to estimate biomass and production accurately, it is concluded that cell volume of tintinnines should be measured directly rather than assumed to be 50% of lorica volume.This research was financed by an NSERC Canada operating grant awarded to Dr D. H. Lynn  相似文献   

19.
Pärtel M  Laanisto L  Zobel M 《Ecology》2007,88(5):1091-1097
The relationship between net primary productivity and biological diversity has been a central topic in ecology for several decades. The unimodal ("hump-back") relationship has been the most widely accepted for plants with the decrease in diversity at high productivity usually attributed to competitive exclusion. However, the relatively small species pool size under high productivity conditions may account for this pattern as well. Small species pool sizes for highly productive habitats are characteristic of temperate regions, where productive habitats for speciation and species migration have historically been rare. In contrast, productive habitats in the tropics have been relatively common during evolutionary history, resulting in large species pools. We hypothesize that evolutionary history contributes to the observed productivity-diversity relationship of plants, and that the productivity-diversity relationship differs between temperate and tropical regions. We investigated the productivity-diversity relationship patterns from 163 case studies throughout the world. Latitude described approximately 80% of the variation in the shape of the relationships. The unimodal relationship was found to dominate in the temperate zone, whereas the positive relationship was significantly more common in the tropics. We detected no influence due to methods of productivity measurement, but unimodal or positive productivity-diversity relationships were more likely within larger ranges of productivity. The length of the productivity gradient did not affect the latitudinal influence. In summary, the shape of the productivity-diversity relationship differs between temperate and tropical regions and the different evolutionary history of the local species pools is a probable cause for the difference.  相似文献   

20.
Passive acoustic monitoring could be a powerful way to assess biodiversity across large spatial and temporal scales. However, extracting meaningful information from recordings can be prohibitively time consuming. Acoustic indices (i.e., a mathematical summary of acoustic energy) offer a relatively rapid method for processing acoustic data and are increasingly used to characterize biological communities. We examined the relationship between acoustic indices and the diversity and abundance of biological sounds in recordings. We reviewed the acoustic‐index literature and found that over 60 indices have been applied to a range of objectives with varying success. We used 36 of the most indicative indices to develop a predictive model of the diversity of animal sounds in recordings. Acoustic data were collected at 43 sites in temperate terrestrial and tropical marine habitats across the continental United States. For terrestrial recordings, random‐forest models with a suite of acoustic indices as covariates predicted Shannon diversity, richness, and total number of biological sounds with high accuracy (R2 ≥ 0.94, mean squared error [MSE] ≤170.2). Among the indices assessed, roughness, acoustic activity, and acoustic richness contributed most to the predictive ability of models. Performance of index models was negatively affected by insect, weather, and anthropogenic sounds. For marine recordings, random‐forest models poorly predicted Shannon diversity, richness, and total number of biological sounds (R2 ≤ 0.40, MSE ≥ 195). Our results suggest that using a combination of relevant acoustic indices in a flexible model can accurately predict the diversity of biological sounds in temperate terrestrial acoustic recordings. Thus, acoustic approaches could be an important contribution to biodiversity monitoring in some habitats.  相似文献   

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