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1.
Lentic community structure varies across a size gradient of ponds and lakes with physical factors, such as pond drying, and biotic factors, such as fish predation, determining the species assemblage. We studied the effects of pond drying and fish absence on crustacean zooplankton across a gradient of pond sizes in a Texas grassland. We determined the species compositions and size distributions of crustacean zooplankton in 20 temporary and 18 permanent ponds in April after March rains had refilled the ponds. The surface areas of temporary and permanent ponds ranged from <0.01 to 0.21 ha and 0.04 to 13.8 ha, respectively, and temporary ponds were significantly smaller, on average, than permanent ponds. Fish were absent from all temporary ponds and present in all permanent ponds. We detected a difference in the zooplankton species assemblages of the temporary and permanent ponds. Out of 14 total zooplankton taxa that occurred in eight or more ponds, seven taxa were significantly more prevalent in temporary ponds and four taxa were significantly more prevalent in permanent ponds. The sizes of zooplankton in the temporary fishless ponds were greater than those in the permanent ponds with fish present. We concluded that pond size mediated susceptibility to pond drying, and pond drying determined the presence and absence of fish and their secondary trophic-level effect on zooplankton community structure. Handling editor: Steven Declerck  相似文献   

2.
Nestedness has been widely used to measure the structure of biological communities and occurs when species-poor sites contain subsets of species-rich ones. Here, we examine nested patterns across the macroinvertebrate assemblages of 91 ponds in Doñana National Park, Spain, and explore temporal variation of nestedness and species richness in 19 temporary ponds over 2 years with differing rainfall. Macroinvertebrate assemblages were significantly nested; both pond spatial arrangement and environmental variation being important in driving nested patterns. Despite the nested structure observed, a number of taxa and ponds deviate from this pattern (termed idiosyncratic), by occurring more frequently than expected in species-poor sites, or having assemblages dominated by species largely absent from species-rich sites. Aquatic adults of winged insects, capable of dispersal, were more highly nested than non-dispersing taxa and life-history stages. Idiosyncratic taxa were found in ponds spanning a wide range of hydroperiods, although nestedness was higher in more permanent waterbodies. Monthly sampling demonstrated a gradual increase of species richness and nestedness from pond filling to April–May, when the most temporary ponds started to dry. Although the degree of nestedness of individual pond assemblages varied from month to month, the overall degree of nestedness in the two study years was practically identical despite marked differences in hydroperiod. Our results suggest that differential colonization and environmental variation are key processes driving the nested structure of Doñana ponds, that macroinvertebrate assemblages change in a predictable manner each year in response to cycles of pond wetting and drying, and that connectivity and environmental variability maintain biodiversity in pond networks.  相似文献   

3.
Biodiversity patterns in cladoceran communities were investigated in urban waterbodies in relation with residential land use, pond management, and waterbody environments. We evaluated species richness in the pelagic and littoral zones of eighteen waterbodies of a large Canadian city. Gamma diversity (26 species) observed at a small scale in the urban survey was important comparatively to large-scale surveys of lakes. Beta diversity ranged from 1 to 8 species among waterbodies. We tested if littoral species greatly contributed to regional diversity in urban waterbodies. Littoral species (Chydoridae, Ilyocryptidae, Macrothricidae, Polyphemidae) accounted for 58% of the total species pool. We distinguished five cladoceran assemblages associated to different waterbodies (temporary ponds, permanent lakes, and wetlands). Cladoceran communities were more diverse and variable in permanent lakes than in temporary ponds. Changes in cladoceran species assemblages among waterbodies were driven by variations in waterbody size and phosphorus enrichment, macrophyte and algal biomass, urban density, pond management practices, and the presence of potential predators as fish and macroinvertebrates. Our study indicates that both artificial ponds and lakes and natural wetlands are valuable habitats for the conservation of cladoceran biodiversity and rare endemic species in urban regions. Further research on pond management strategies promoting urban aquatic biodiversity should be undertaken.  相似文献   

4.
The influence of different macrophyte taxa or growth forms on biological and environmental variables is often analysed in one-lake studies. However, the unique combination of non-vegetational characteristics of a waterbody, i.e. its site identity, can be an influential factor in itself, shaping the measured parameters irrespective of the presence or absence of certain macrophyte species. In this situation, the relative strengths of all factors can be determined best in a study that explicitly accounts for differences in the identity of the waterbodies. Several functional macrophyte groups are known to provide a potent microinvertebrate refuge or permanent habitat. The objective of this study was to detect patterns in the zooplankton assemblages associated with different extensive habitats of macrophyte species and to relate these patterns to three major factors: the microhabitat, the pond identity and the seasonality in the warmer months of the year. Five ponds located in the Woluwe catchment of the Brussels-Capital Region (Belgium) were studied monthly for macrophyte and zooplankton characteristics from July until October 2005. The vegetation in the clear ponds was characterized by extensive monospecific stands (Ceratophyllum, Chara, Nitella, Potamogeton, Nuphar and filamentous algae). Zooplankton could be analysed in seven different vegetation types and in the open water zones and contained a total of 17 cladoceran and 27 rotifer genera. Principal components analysis (PCA) ordination of zooplankton communities showed a seasonal gradient and a tendency to group within-pond habitats, although they differed in macrophyte species and habitat structure. Despite the absence of clustering of similar microhabitats across ponds, percent volume infested (PVI), vegetation biomass density and Daphnia length (used as a proxy for fish predation pressure) contributed significantly positive to the Shannon zooplankton biodiversity indices. Moreover, densities of most zooplankton subgroups and of total zooplankton were significantly and positively related to PVI. It is assumed that in eutrophic ponds, extensive, often monospecific macrophyte vegetations provide an ecological environment suitable for both macrophyte-associated species and migrating pelagic zooplankton, thereby maintaining a high microinvertebrate biodiversity.  相似文献   

5.
6.
The current interest in Mediterranean temporary wet habitats, considered to be habitats of European Community Interest, is mainly due to their characteristic flora and fauna. Several contributions characterize each of these two components separately, but considering them simultaneously could reveal possible interactions and a more complete view of the habitat that would be useful to improve conservation measures. This paper investigates crustacean and plant assemblages in six Mediterranean temporary ponds and their relationship with several environmental variables. Significant positive relationships were found between species richness and Shannon diversity index of plant and crustacean assemblages. Crustaceans had a higher similarity among ponds than plants and, consequently, each pond had a more characteristic assemblage of plants than of crustaceans. The two groups showed a different sensitivity to environmental factors and only two factors affected both: altitude and surface area of the wet system. Disturbances (e.g. grazing by cattle) and pond size were very important for plants, whereas they were irrelevant for crustaceans. On the other hand, distance to the nearest pond, hydroperiod length, and water nitrogen were only important for crustaceans. Although similar trends on richness and diversity were observed for both biotic groups, the use of only one of them for conservation programs would not be sufficient. Our results suggest that simultaneously taking into account several community components would result in a better understanding of ecosystem functionality.  相似文献   

7.
1. In lentic freshwater habitats, the composition of animal assemblages shifts along a gradient from temporary to permanent basins. When habitats with different degrees of permanence are at the scale of the home range of species, they constitute alternatives in terms of energy acquisition through feeding. 2. In this context, previous studies showed an advantage of metamorphic over paedomorphic tiger salamanders (Ambystoma tigrinum) in temporary ponds which are only available to metamorphs. The aim of this study was to establish whether salamanders obtain similar benefits in ponds that do not differ in water permanence and whether salamanders shifted from detrimental to advantageous ponds. To this end, we determined the feeding habits, body condition and movement patterns of the two morphs in a complex of four permanent and four temporary ponds. 3. Consistent with previous studies, metamorphs consumed higher‐quality diets than paedomorphs in term of energy intake. However, these differences occurred because metamorphs consumed fairy shrimp in a single temporary pond. Individual movement patterns confirmed that most of the metamorphs used different aquatic habitats both within and between years and that most of them moved from permanent ponds for breeding towards the most profitable temporary pond in terms of foraging. 4. These results indicate that habitat selection by salamanders is optimal in term of energy intake in metamorphs that use high quality ponds independently of hydroperiod. It seems that both spatial and temporal variation can influence the relative foraging success of each morph.  相似文献   

8.
Invertebrate communities and turnover in wetland ponds affected by drought   总被引:6,自引:0,他引:6  
1. Changes to the macroinvertebrate fauna found in small ponds on a freshwater marsh (Aberlady Bay, Scotland) in 1986, 1987 and 1992 were used to assess the impact of the 1988–92 drought on taxon turnover in pond communities. 2. Permanent ponds accumulated taxa over the study period. Ponds that were wet throughout 1986–87 but dried in 1992 lost some of the many taxa associated with permanent water but acquired a reduced fauna typical of temporary ponds. Ponds that were temporary in 1986–87 were dry during most of 1992 and lost almost all aquatic taxa. 3. Faunal turnover was considerable even in permanent ponds. Extinction rates were high for taxa typical of permanent or temporary ponds. Colonization rates were poor for the taxa from permanent water, but high for the taxa from temporary ponds. 4. The importance of colonization and extinction rates as main predictors of the distribution of species between the ponds was looked at using metapopulation incidence functions, where observed incidence of a taxon can be used to predict colonization and extinction rates. Predicted rates were then compared with observed rates. Incidence functions gave reasonable predictions of observed colonization rates but were poor predictors of extinction, even for taxa that appeared likely to be true metapopulations. 5. For the pond fauna, including fugitive species adapted to temporary ponds, whilst colonization may well depend on environmental stochasricity (how long a pond holds water), subsequent survival depends on other, demographic, processes (e.g. finding a mate, predation) rather than the pond drying out.  相似文献   

9.
Freshwater habitats are important elements within urban green space and they are endangered by various types of human activity. With the aim to increase the knowledge about species biodiversity in urban ecosystems, we characterised the assemblages of aquatic insects in four permanent man-made ponds in Buenos Aires city (Argentina) during a 1-year period. We recorded 32 species with Sigara spp. (Hemiptera) as the most abundant. The removal of aquatic vegetation from the studied ponds may have affected both the establishment and permanence of the insect community. Swimmers were the dominant group in the studied sites, followed by burrowers and sprawlers, and only a few strictly climbers were collected. Therefore, all sampled ponds were dominated by collectors (principally gatherers), secondarily by predators and only few shredders were detected, which was much affected by the removal of macrophytes. Non-parametric abundance indexes estimated a number of species very close to the observed number in each site. Conversely, the incidence indexes estimated more species because there were many more taxa present only in one sample than those represented by few individual in a sample. Our data provides some insights on the community of man-made ponds that can improve the management of these aquatic urban habitats. Considering that macrophytes affect animal assemblages due to their role as physical structures that increase the complexity or heterogeneity of habitats, they should not be removed by authorities in order to promote biodiversity.  相似文献   

10.
Understanding spatial and temporal breeding patterns in Mediterranean amphibian communities is urgent considering the rate of habitat loss. Breeding phenology and breeding habitat selection by amphibians were analysed through the monthly occurrence of larvae in a mosaic of 198 Mediterranean temporary ponds during three years. A generalized linear model (GLM) coupled with principal component analysis showed that, for almost all species, occurrence was significantly positively correlated to pond depth. In addition, pond openness negatively affected the presence of some species. Temporal breeding patterns varied among species. Some species exhibited flexibility in their breeding date (Pelobates cultripes, Pelodytes punctatus, Hyla meridionalis, Rana perezi), while others did not (Triturus marmoratus, Triturus helveticus, Bufo calamita). When faced with inter-annual hydrological variability, the first group had a more constant breeding success than the second. Variable hydrological conditions caused differential larval occurrence of species between years. These fluctuations might favour long-term persistence of the whole amphibian community. We finally discuss the implications of our results for the management of amphibian habitats in the Mediterranean region.  相似文献   

11.
Relating fish kills to upwellings and wind patterns in the Salton Sea   总被引:1,自引:0,他引:1  
Awareness of pond conservation value is growing all over Europe. Ponds are recognized as important ecosystems supporting large numbers of species and several rare and threatened aquatic plants, macroinvertebrates and amphibians. Notwithstanding ponds, particularly temporary ones, are still neglected in Italy. There are some gaps in our understanding of the macrophyte ecology and the conservation value of Mediterranean small still waters. Therefore, this study investigated the macrophyte communities and physico-chemical characteristics of 8 permanent and 13 temporary ponds along the Tyrrhenian coast near Rome, with the aim to relate the distribution of aquatic plants to environmental variables, and to define the botanical conservation value of ponds. Throughout the study period (Spring 2002), Principal Component Analysis performed on abiotic variables clearly discriminated temporary ponds, smaller and more eutrophic, from permanent ponds, larger and with higher pH and oxygen concentration. A total of 73 macrophyte taxa were collected in the study ponds. Temporary waters hosted a smaller number of plant species than permanent ones. Besides hydroperiod length, the environmental factors related to plant richness were maximum depth, surface area, dissolved oxygen and nitrogen concentration in the water. Moreover, the Non-metric Multidimensional Scaling showed a high dissimilarity in the taxonomic composition of aquatic plants between temporary and permanent ponds. The former contained more annual fast-growing species (Callitriche sp. pl. and Ranunculus sp. pl.), while in the latter species with long life-cycles (i.e. Potamogeton sp. pl.) were more abundant. Our results highlighted that temporary and permanent ponds in central Italy have different macrophyte assemblages, with aquatic species (including some of conservation interest at regional scale) exclusively found in each pond type. This suggested that both type of ponds could give an irreplaceable contribution to the conservation of aquatic plant diversity of these freshwater ecosystems. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat  相似文献   

12.
13.
We assessed the importance for biodiversity of man-made farm ponds in an agricultural landscape in SW France lacking natural wetlands. The ponds were originally created to provide a variety of societal services (irrigation, visual amenity, water for cattle, etc.). We also assessed the environmental factors influencing invertebrate assemblages in these ponds. Only 18 invertebrate taxa out of 114 taxa occurring in the study area were common to ponds and rivers indicating that the contribution of farm ponds to freshwater biodiversity was potentially high. A Self-Organizing Map (SOM, neural network) was used to classify 36 farm ponds in terms of the 52 invertebrate families and genera they supported, and to specify the influence of environmental variables related to land-use and to pond characteristics on the assemblage patterns. The SOM trained with taxa occurrences showed five clusters of ponds, most taxa occurring only in 1–2 clusters of ponds. Abandoned ponds tended to support higher numbers of taxa, probably because they were allowed to undergo a natural succession. Nevertheless, abandoned ponds were also amongst the largest, so that it remained difficult to separate the effects of pond size and abandonment, although both factors were likely to interact to favour higher taxon richness. The invertebrate communities in the ponds appeared to be influenced mainly by widely acting environmental factors (e.g. area, regionalization of assemblages) with little evidence that pond use (e.g. cattle watering, amenity) generally influenced assemblage composition. Our results support the idea that agricultural landscapes containing man-made ponds make a significant contribution to freshwater biodiversity indicating that protection of farm ponds from threats such as in-filling and pollution can make a positive contribution to the maintenance of aquatic biodiversity. This added value for biodiversity should be considered when calculating the economic costs and benefits of constructing water bodies for human activities. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat  相似文献   

14.
There is growing awareness in Europe of the importance of ponds, and increasing understanding of the contribution they make to aquatic biodiversity and catchment functions. Collectively, they support considerably more species, and specifically more scarce species, than other freshwater waterbody types. Ponds create links (or stepping stones) between existing aquatic habitats, but also provide ecosystem services such as nutrient interception, hydrological regulation, etc. In addition, ponds are powerful model systems for studies in ecology, evolutionary biology and conservation biology, and can be used as sentinel systems in the monitoring of global change. Ponds have begun to receive greater protection, particularly in the Mediterranean regions of Europe, as a result of the identification of Mediterranean temporary ponds as a priority in the EU Habitats Directive. Despite this, they remain excluded from the provisions of the Water Framework Directive, even though this is intended to ensure the good status of all waters. There is now a need to strengthen, develop and coordinate existing initiatives, and to build a common framework in order to establish a sound scientific and practical basis for pond conservation in Europe. The articles presented in this issue are intended to explore scientific problems to be solved in order to increase the understanding and the protection of ponds, to highlight those aspects of pond ecology that are relevant to freshwater science, and to bring out research areas which are likely to prove fruitful for further investigation. Guest editors: R. Céréghino, J. Biggs, B. Oertli and S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat  相似文献   

15.
1. Broad‐scale assessments of biodiversity often rely on the use of surrogate taxa, whose reliability has rarely been tested, particularly in freshwater systems. Here we use data from 46 ponds in two regions of the U.K. to explore the performance of macroinvertebrate taxa as surrogates for the rapid assessment of pond biodiversity. For the four dominant taxonomic groups in these ponds (Chironomidae, Coleoptera, Gastropoda and Trichoptera) we explore cross‐taxon species richness relationships in each of the two regions, and also determine the degree of concordance between the different taxa in accurately representing the similarity relationships between pond assemblages. 2. Patterns of cross‐taxon congruence in species richness were highly variable among taxa and study sites, making the use of a single taxon as a predictor of overall macroinvertebrate species richness problematic. In contrast, all four taxa show >70% congruence with the pattern of community similarity between sites resulting from the entire macroinvertebrate dataset, this result being consistent within and between regions. Canonical correspondence analysis demonstrated that all taxa were related in a similar manner to measured environmental parameters, meaning that limited additional ecological information is gained by including a wider range of pond taxa in rapid site assessment. 3. Single taxonomic groups can, therefore, perform consistently as indicators of community similarity between ponds, and no one taxon dramatically outperforms any other in this respect. The relative merits of the four focal taxa as surrogates for pond invertebrate assemblage composition are discussed with reference to ease of survey, ease of identification and ecological range occupied. 4. It is suggested that Coleoptera have a number of advantages as a surrogate taxon, being diverse, easily sampled, readily identified, taxonomically stable, ecologically well understood and occurring across a wide spectrum of pond types. They are therefore recommended for use as a focal group in rapid pond biodiversity assessments, employing an approach such as ours, which examines patterns of assemblage similarity, rather than species richness alone.  相似文献   

16.
Ponds support a rich biodiversity. This arises in part because of the number and heterogeneity of ponds spatially throughout the landscape. Studies of ponds suggest that distinct communities develop within individual ponds but most examples are based on short-term 1- or 2-year surveys which cannot identify the effects of historic events upon contemporary communities. This study reports the development and turnover of the early summer macroinvertebrate communities in thirty small temporary ponds from their creation in 1994 over 10 years to 2004. Distinct pioneer communities established in the first year of the ponds’ creation, the first 3 years dominated by a fauna associated with long summer dry phases. Then a sustained period of inundation lasting 27 months from summer 1997–1999 resulted in establishment of many taxa associated with permanent ponds and loss of some temporary pond species. The re-establishment of summer dry phases in 1999 was associated with the loss of some but not all of the permanent water taxa and re-colonisation by some temporary water species creating new communities combining these different elements. The communities were not a linear successional sequence; the communities that re-assembled following resumption of dry phases reflected the contingent history of each pond and the effects of historic events. The longer term nature of the study showed that the characteristic heterogeneity of pond invertebrate communities occurs through time as well as spatially and that the richness and variety of contemporary communities, which is often hard to explain from snap-shot studies, is partly the result of historic events.  相似文献   

17.
Temporal stability of pond zooplankton assemblages   总被引:1,自引:0,他引:1  
1. A large body of recent theory has recently developed focused on the relationship between the species diversity of competitor assemblages and the temporal stability of total competitor biomass. Many of these models predict that stability can increase with increasing diversity. 2. To explore natural relationships between zooplankton taxonomic diversity and temporal stability of total zooplankton biomass, 18 fishless, permanent ponds located in southern Michigan were surveyed over a 5 month period during a single growing season. 3. Results showed that temporal variability in total zooplankton biomass (measured as the coefficient of variation or CV) decreased with increasing mean zooplankton taxonomic richness. Thus, temporal stability increased with increasing taxonomic richness, consistent with theoretical predictions. 4. Decreases in the CV appeared to be because of portfolio effects (statistical averaging of species’ biomass fluctuations) rather than negative covariances among zooplankton taxa. 5. The CV of zooplankton biomass was also related to several environmental variables, suggesting that taxonomic richness may not be the only mediator of biomass stability. The CV decreased with increasing relative abundance of grazer‐resistant algae (algae >35 μm in size) and the CV increased with increasing pond productivity.  相似文献   

18.
 The objective of this study was to determine if pond permanence and vertebrate predation (by fish and waterfowl) affect invertebrate community structure in the mudflat habitat of floodplain ponds. Invertebrate communities were studied for 1 year in four Mississippi River floodplain ponds with different hydroperiods. Pond 1 experienced five dry periods, pond 2 experienced four, pond 3 dried once, and standing water remained in pond 4 for the entire year. Vertebrate predator exclusion treatments (all access, no access, small-fish access and cage controls) were placed in all ponds. As pond duration increased, predatory invertebrate richness and abundance increased while overall invertebrate richness and abundance decreased. With the exception of the cladoceran Diaphanosoma, all commonly encountered taxa were strongly affected by pond permanence in terms of abundance, biomass and, generally, individual biomass. Taxa were nearly early divided between those that were more abundant in less permanent ponds and those that were more abundant in longer-duration ponds. Invertebrate taxa richness, abundance, and total biomass were lower in the all-access treatment than in the treatments that restricted predator access, and these effects were stronger in the more permanent ponds. In general, there were no significant differences in responses to the treatments with small-fish access and no access. These results support models that predict relatively weak effects of predation in frequently disturbed habitats. Received: 30 May 1995 / Accepted: 21 June 1996  相似文献   

19.
Differences in the dynamics of ecological processes between Mediterranean and colder temperate aquatic systems could imply different patterns in faunal communities in terms of composition and biodiversity (i.e. species richness and rarity). In order to identify some of these patterns the crustacean and aquatic insect composition and biodiversity of four water body types, classified according to their salinity and water permanence, were compared. Moreover, the relationships between species richness and water, pond and landscape variables were analysed. A total number of 91 water bodies located throughout Catalunya (NE Iberian Peninsula) were sampled. Three species assemblages were observed: one for permanent freshwaters, another for temporary freshwaters, and a third one for saline waters (SW), since permanent and temporary saline water bodies had similar composition. Differences in salinity were associated with proportion of crustaceans versus insects and with singularity. Thus, saline ponds had a higher proportion of crustaceans, and lower values of singularity. Conductivity was significantly related to total (crustaceans plus insects) richness, and also related to insect richness. The main difference between the models obtained for crustacean species richness and insect species richness is the significance of landscape variables in the latter, and this fact could be related to the different dispersion types of these two faunal groups: active for insects versus passive for crustaceans. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat  相似文献   

20.
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