Crustacean zooplankton community structure in temporary and permanent grassland ponds

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     

The typology of temporary waterbodies and the influence of their parameters on the crustacean species composition of zooplankton

The typology of temporary waterbodies in Saratov oblast has developed with a similarity in the composition of zooplankton species that serve as its foundation. Seven waterbody groups have been distinguished: waterbodies of flood lands, river valley terraces, steppe watersheds, brackish lagoons, brackish lagoons connected to irrigation networks, excavated ponds, and puddles. The specificity of zooplankton species composition in different types of temporary waterbodies is shown. A significant influence of waterbody lifetime on the number of zooplankton species has been revealed, with the waterbody capacity and surface area in the period of maximal water level also being of great importance.     

Evaluating environmental conditions of a temporary pond complex using rotifer emergence from dry soils

In this study we evaluated the usefulness of rotifer emergence from dry soils to indicate the environmental status of a remnant temporary pond complex in an agricultural area in central Spain. Because the ponds did not flood during our project, emergence was studied in relation to environmental variables in outdoor microcosms. Redundancy analysis and nestedness analysis showed that salinity and total nitrogen concentrations shaped the emerged communities. Depauperate rotifer assemblages from pond microcosms with higher salinity and nitrogen levels were nested subsets of species-rich communities from microcosms of less enriched sites. Rotifer community structure also identified small ponds as reference sites that should receive priority in conservation and degradation mitigation programs. Results suggest that rotifer emergence from rewetted sediments using microcosms can be useful for evaluating the nutrient status during the dry phase of temporary wetlands. While results from this approach are conservative, requiring comparisons with field observations, their tentative value lies in alerting management and providing a basis for future research of poorly studied but threatened temporary habitats. Rotifer emergence could be a useful alternative to traditional biological indicators of nutrient status that depend on the presence of water.     

Flood-mediated dispersal versus hatching: early recolonisation strategies of copepods in floodplain ponds

1. We explored the quantitative contribution of two alternative recolonisation strategies by a combination of experimental and field data from the Little Tallahatchie floodplain (Mississippi, U.S.A.). In this area, several floods of short duration occur in winter and spring. During floods, lentic and lotic waterbodies of different size are connected for a limited period. 2. Shortly before the onset of the flood season we collected sediment samples from six temporary ponds. The emergence of seven cyclopoid species was recorded from the experimentally flooded sediments and was quantified over a 4‐week period. Water samples were taken in the same ponds after flooding, from which eight further species were recorded and quantified. 3. The contribution of flood‐dispersed individuals was variable among flooded ponds (between 38 and 94%), but numbers of flood‐dispersed colonists did not differ significantly from those of hatching individuals in flooded ponds. Our results demonstrate the equal importance of both hydrological connections and hatching from dormant stages as pathways for recolonisation by copepods if ponds are hydrologically connected. 4. The significance of recolonisation by hatching individuals in disconnected waterbodies was apparent in an isolated temporary pond that was exclusively recolonised by cyclopoid copepods emerging from the sediment.     

Spatial and biocenotic trends in the water-mite fauna of small ponds

Forty-one permanent and temporary ponds have been studied in a mountain range in the center of Spain. Abiotic variables are used to characterize the ponds. Spatial and biocenotic distribution patterns of macroinvertebrates with special reference to the water mite fauna are considered. Order of authorship determined by the toss of a coin. Order of authorship determined by the toss of a coin.     

Analyzing species distributions among temporary ponds with a permutation test approach to the join-count statistic

The Bluff Springs Sand Ponds (BSSPs) are a set of closely-spaced temporary ponds of varying hydroperiod, depth and surface area. We sampled crustacean communities of 15 ponds throughout hydroperiods in 1996 to examine species distributions among ponds. Although ponds were closely spaced (within ca. 16 ha), most species were present in subsets of the 15 ponds. We then analyzed spatial patterns of 12 crustacean species for complete spatial randomness (CSR) using join-count statistics. However, the join-count was designed for large-samples (n>50), so we further analyzed (by simulation) the join-count and a variation of the join-count (Cliff & Ord, 1981) for small-scale reliability. Simulation results revealed that neither testing distribution was reliable for n<30. We then used a permutation test to analyze species distributions and concluded that some species were distributed non-randomly. Therefore, further investigations of mechanisms causing species distributions (e.g., hydroperiod, physical/chemical conditions, biotic interactions) are clearly prescribed. The permutation test should be useful for studies of species distribution patterns among other temporary waters, and can help focus studies on causal mechanisms of distributions among small numbers of temporary aquatic habitats.     

Foraging tactics in alternative heterochronic salamander morphs: trophic quality of ponds matters more than water permanency

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.     

Assessing the efficacy of chironomid and diatom assemblages in tracking eutrophication in High Arctic sewage ponds

Eutrophication is the most common water quality issue affecting freshwaters worldwide. Paleolimnological approaches have been used in temperate regions to track eutrophication over time, placing changes in historical context. Diatoms (Bacillariophyta) have a direct physiological response to changes in nutrients and are effective indicators of lake trophic status. Chironomids (Diptera) have also been used to track nutrient conditions; however, given that nutrients and oxygen are often tightly linked, it is difficult to disentangle which variable is driving shifts in assemblages. Here, we analyze chironomid and diatom remains in sediments from sewage-impacted ponds in the High Arctic. These ponds have the unusual characteristics of elevated nutrient and oxygen concentrations, unlike those of typical eutrophic lakes where deepwater oxygen is often depleted. Our data show that while diatom assemblages responded to changing nutrients, no concomitant changes in chironomid assemblage composition were recorded. Furthermore, the dominance of oligotrophic, cold stenothermic chironomid taxa, and lack of so-called “eutrophic” species in the eutrophic sewage ponds suggests that oxygen, not nutrients, structures chironomid assemblages at these sites.     

Effects of hydrology on zooplankton communities in high-mountain ponds, Mount Rainier National Park, USA

Ten high-mountain ponds in Mount Rainier National Park, WashingtonState, were studied from ice-out in June through September1992to investigate the influences of fluctuating pond volumes onzooplankton communities. All of the ponds were at maximum volumeimmediately after ice-out. The temporary pond with the shortestwet phase was inhabited by rotifer taxa with short generationtimes and a crustacean taxon with the ability to encyst as drought-resistantresting bodies at immature stages of development. Dominant zooplanktontaxa in three other temporary ponds and six permanent pondswere similar. Rotifer densities typically were lower in temporaryponds relative to those in permanent ponds, although Brachionusurceolaris was abundant shortly before the temporary ponds dried.Large volume loss was associated with large declines in totalabundances of crustacean populations. Daphnia rosea was notpresent in temporary ponds following fall recharge. In deep-permanentponds, copepods had slower developmental rates, smaller temporalchanges in total abundances of crustacean populations and twoadditional large-bodied crustacean taxa were present relativeto the characteristics of crustacean communities in shallow-permanentponds. Owing to their small sizes and sensitivity to environmentalchange, collectively ponds such as these may provide an earlysignal of long-term climate change in aquatic systems.     

Plant communities as a tool in temporary ponds conservation in SW Portugal

Temporary ponds are seasonal wetlands annually subjected to extreme and unstable ecological conditions, neither truly aquatic nor truly terrestrial. This habitat and its flora have been poorly studied and documented because of the ephemeral character of the flora, the changeable annual weather that has a great effect on the small, herbaceous taxa and the declining abundance of temporary ponds. The objectives of this study are: (a) to define plant community diversity in terms of floristic composition of ephemeral wetlands in SW Portugal, (b) to identify temporary pond types according to their vegetation composition and (c) to identify those ponds that configure the European community priority habitat (3170* – Mediterranean temporary ponds). Vegetation sampling was conducted in 29 ponds, identifying 168 species grouped among 15 plant communities. Soil texture, pH, organic C and N content were measured, but only N and percent of clay appear to be related with the distribution of each community type. The results showed that ephemeral wetlands could be classified into four type: vernal pools, marshlands, deep ponds and disturbed wetlands. Vernal pools correspond to the Mediterranean temporary ponds (3170*), protected as priority habitat under the EU Habitats Directive. Submersed Isoetes species (Isoetes setaceum and Isoetes velatum) represents, together with Eryngium corniculatum, the indicator species for vernal pools. We identify also indicator plant communities of this priority habitat, namely I. setaceum and E. corniculatum–Baldellia ranunculoides plant communities. In this region, the conservation of temporary ponds has so far been compatible with traditional agricultural activities, but today these ponds are endangered by the intensification of agriculture and the loss of traditional land use practices and by the development of tourism. Guest editors: B. Oertli, R. Cereghino, A. Hull & R. Miracle Pond Conservation: From Science to Practice. 3rd Conference of the European Pond Conservation Network, Valencia, Spain, 14–16 May 2008     

Changes in sediment phosphate composition of seasonal ponds during filling

Most ponds from the Doñana National Park are shallow temporary freshwater bodies on eolian sands. The total phosphate concentration and the fractional P-composition of the sediments from two small ponds were studied before and inmediately after they were filled (autumn, 1996). Total phosphorus concentration was measured in 2 different size fractions: 2–0.1 mm (coarse) and <0.1 mm (fine). In both ponds, the total phosphorus concentration of the fine sediment increased by 20% at the beginning of the filling period, whereas 5 weeks later it did not increase further. The percentage of organic matter of the fine sediment was relatively high (between 13–18%) and did not change significantly during filling. The concentration of sediment total iron and Fe(OOH) increased significantly in both ponds during filling. The sequential P fractionation of the fine sediment included, besides the determination of two inorganic fractions (Ca-bound P and Fe-bound P), an organic-P fraction extracted with acid, another extracted with alkali, two organic-P fractios from the Ca-EDTA/dithionite and the Na₂-EDTA extracts which contained high concentrations of humic substances. The pond sediments were rich in organic P compounds as the sum of all organic-P fractions ranged between 267 and 320 g g^-1 (68% and 79% of the sum of all fractions). Significant changes (P<0.01) in the fractional P-composition of sediments were found after filling. Acid soluble organic phosphate increased about 30% in both ponds. Iron-bound phosphate increased significantly (about 40%) only in the pond where a higher concentration of Fe(OOH) was measured after filling. An adsorption experiment was carried out for each sediment to simulate P input during filling. Both the iron-bound phosphate and Ca-bound P increased significantly (P<0.01) suggesting that these two fractions were involved in the P-adsorption during the laboratory experiment.     

Review of ammonia-oxidizing bacteria and archaea in freshwater ponds

Aquaculture ponds are simple and unique ecosystems, which are affected intensively by human activities. In this mini-review, we focus our attention on the distribution and community diversity of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in pond water and sediments, as well as the possible ecological mechanisms involved. Moreover, we discuss the possibility of increasing the activity of ammonia-oxidizing organisms in order to improve the water quality in aquaculture ponds. Compared with eutrophic lakes, the significantly higher ammonia concentration in pond water does not lead to significantly higher AOB levels, and the abundance of AOA is too low to quantify accurately. Similar to eutrophic lakes, high abundances of AOA and AOB are present in the surface sediments at the same time, where the oxidation of ammonia is performed mainly by AOB. AOB and AOA exhibit significant seasonal variations in aquaculture ponds, which are affected by the temperature, pH, and dissolved oxygen. The dominant AOB species are Nitrosomonas and the Nitrosospira lineage in pond environments. Nitrososphaera or members of the Nitrososphaera-like cluster dominate the AOA species in surface sediments, whereas the Nitrosopumilus cluster dominates the deeper sediments. AOB and AOA can be enriched on artificial substrates suspended in the pond water, thereby potentially improving the water quality.

     

Sediments in Marsh Ponds of the Gulf Coast Chenier Plain: Effects of Structural Marsh Management and Salinity

Physical characteristics of sediments in coastal marsh ponds (flooded zones of marsh associated with little vegetation) have important ecological consequences because they determine compositions of benthic invertebrate communities, which in turn influence compositions of waterbird communities. Sediments in marsh ponds of the Gulf Coast Chenier Plain potentially are affected by (1) structural marsh management (levees, water control structures and impoundments; SMM), and (2) variation in salinity. Based on available literature concerning effects of SMM on sediments in emergent plant zones (zones of marsh occasionally flooded and associated with dense vegetation) of coastal marshes, we predicted that SMM would increase sediment carbon content and sediment hardness, and decrease oxygen penetration (O₂ depth) and the silt-clay fraction in marsh pond sediments. Assuming that freshwater marshes are more productive than are saline marshes, we also predicted that sediments of impounded freshwater marsh ponds would contain more carbon than those of impounded oligohaline and mesohaline marsh ponds, whereas C:N ratio, sediment hardness, silt-clay fraction, and O₂ depth would be similar among pond types. Accordingly, we measured sediment variables within ponds of impounded and unimpounded marshes on Rockefeller State Wildlife Refuge, near Grand Chenier, Louisiana. To test the above predictions, we compared sediment variables (1) between ponds of impounded (IM) and unimpounded mesohaline marshes (UM), and (2) among ponds of impounded freshwater (IF), oligohaline (IO), and mesohaline (IM) marshes. An a priori multivariate analysis of variance (MANOVA) contrast indicated that sediments differed between IM and UM marsh ponds. As predicted, the silt-clay fraction and O₂ depth were lower and carbon content, C:N ratio, and sediment hardness were higher in IM than in UM marsh ponds. An a priori MANOVA contrast also indicated that sediments differed among IF, IO, and IM marsh ponds. As predicted, carbon content was higher in IF marsh ponds than in ponds of other impounded marsh types. In contrast to our predictions, C:N ratio and sediment hardness were lowest and silt-clay fraction and O₂ depth were highest in IO and IM marsh ponds. Our results indicated that SMM has affected physical properties of sediments in coastal marsh ponds. Moreover, sediments in IF marsh ponds were affected more so than were those in IO and IM marsh ponds. Our results, in conjunction with those of previous studies, indicated that sediments of marsh ponds and emergent plant zones differed greatly. We predict that changes in pond sediments due to SMM will promote greater epifaunal macroinvertebrate biomass, which in turn should attract larger populations of wintering waterbirds. However, waterbirds that filter or probe soft sediments may be negatively affected by SMM because of the expected decrease in infaunal invertebrate biomass.     

Relating fish kills to upwellings and wind patterns in the Salton Sea

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     

Diversity,taxonomy and autecology of autochtonous epipelic cyanobacteria of the genus <Emphasis Type="Italic">Komvophoron</Emphasis> (Borziaceae,Oscillatoriales): a study on populations from the Czech Republic and British Isles

Epipelic cyanobacteria were studied in bottom sediments from ponds and lakes in the United Kingdom and the Czech Republic, covering a trophic gradient from deep, oligotrophic, glacial lakes to shallow, eutrophic, urban manmade ponds. Although many planktic species were observed, the most frequently occurring cyanobacteria were the motile filamentous genera Oscillatoria, Phormidium, Pseudanabaena and Komvophoron. These genera represent autochtonous epipelic assemblages, occurring in upper surface layers of the sediments throughout the year and exhibiting seasonal variation in their abundancy. The occurrence of individual Komvophoron species was influenced by sediment quality, particularly the proportions of fine mud and organic detritus. A new species Komvophoron hindakii sp. nov. is described. Morphological features, autecology and occurrence of all the Komvophoron-like morphospecies found are discussed.     

Livestock disturbances in Mediterranean temporary ponds: A mesocosm experiment with sheep manure and simulated trampling

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Sexual reproduction and diapause of Hexarthra sp. (Rotifera) in short-lived ponds in the Chihuahuan Desert

1. In the life cycle of monogonont rotifers it is generally assumed that diapausing eggs invariably hatch into amictic stem females which produce female offspring parthenogenetically. Diapausing eggs are only produced by later generations after sexual reproduction has been induced by environmental cues. 2. We show that populations of an undescribed Hexarthra species inhabiting small temporary ponds in the Chihuahuan Desert deviate from this life cycle pattern. These ponds may dry within days and up to 85% of females were mictic. Females producing male offspring and diapausing eggs were observed 1 or 2 days, respectively, after ponds had filled with water. 3. Under laboratory conditions, 7–46% of females hatching from re‐hydrated sediments were sexual. Male offspring of these females can fertilise other mictic stem females leading to diapausing egg formation. In laboratory experiments, females produced fully developed diapausing eggs within 1.9 days at 20 °C and 1.2 days at 30 °C. 4. In addition, embryonic development time (1.1–0.3 days at temperatures between 12 and 30 °C) and juvenile period (2.1–0.5 days for the same temperature range) are shorter than those of other rotifer species. In short‐lived habitats, the potential for rapid population development and production of new diapausing eggs may be crucial in the long‐term survival of populations.     

Patterns in rotifer diapausing egg banks: Density and viability

Here we present a quantitative study on the density, age and viability of the diapausing egg banks of the rotifer species complex Brachionus plicatilis in the sediments of 15 water bodies from Eastern Spain. Sampled ponds, located in coastal and inland areas, varied in salinity and ranged in size, depth and permanence. By identifying ‘hatched’, ‘deteriorated’ and ‘viable’ diapausing eggs in the sediment samples, we estimated production, hatching and deterioration in relation to the habitat properties of each pond. Our results indicate the presence of large numbers of diapausing eggs in the sediments of almost all of the ponds studied (2-115 eggs cm^− 2). Inland ponds tended to have higher densities than coastal lagoons. The vertical distribution of eggs in the sediments frequently showed a non-decreasing pattern, which suggested a high among-year variation in egg production. Despite maximum age of eggs of 60-80 years, the median age (3-30 years) suggests that rotifer egg banks are young in the studied ponds. Egg senescence is suggested by the declining abundance of ‘healthy-looking’ eggs with depth. The proportion of ‘deteriorated’ eggs ranged 75-99% suggesting that deterioration rates in the sediments are high and vary among habitats. Hatching and deterioration rates, as estimated from the counts of ‘hatched’, ‘deteriorated’ and ‘healthy-looking’ eggs in the sediments, largely varied among ponds. An association between hatching and deterioration rates is suggested by our data. This is in agreement with the hypothesis that hatching rates of diapausing eggs depended not only on the risks associated with the water column, as initially expected by the general theory on diapause, but they are also related to the incidence of deterioration processes in the sediment.     

The impact of environmental factors on the diversity of gastropod communities in sinkhole ponds in a coal mining region (Silesian Upland,Southern Poland)

Studies on the diversity of gastropod fauna were carried out in ten sinkhole ponds with varied sediments types, which were located in a coal mining area (Silesian Upland, Southern Poland). The water bodies with different bottom types were distinguished by their dissimilar water properties and the total organic matter in the sediment. A total of 11 gastropod species from four families were identified. Eleven species occurred in sinkhole ponds with a coal shale bottom, while in water bodies with sandy sediments nine species were found. The gastropod diversity and abundance were lower in water bodies with sandy sediments compared to the ponds with a coal shale bottom. Canonical correspondence analysis (CCA) showed the important factors that influence the gastropod distribution in the subsidence ponds that were studied.