Permanent Pools Research Articles

Effects of food supply and stream physical characteristics on habitat use of a stream‐dwelling fish

AbstractIdentifying the environmental factors that affect freshwater fish can be crucial for their conservation and management. Despite the widespread investigation of relationships between fish habitat use and environmental variables, there is a paucity of knowledge on how abiotic and biotic factors jointly influence stream fish habitat use. Three New Zealand South Island streams were selected to investigate the habitat preference of a stream‐dwelling galaxiid, banded kokopu (Galaxias fasciatus). Fish abundance in several permanent pools was determined by spotlighting at night once a month from June 2008 to May 2009. Drifting invertebrates and key physical features of each pool were measured at the time of fish sampling. An information‐theoretic approach (AIC) indicated that the most parsimonious candidate model to predict banded kokopu biomass was the one that included pool area, undercut banks, water velocity, overhanging vegetation, invertebrate drift density and an interaction term between invertebrate drift density and water velocity. Banded kokopu biomass was positively related to pool area, undercut banks, overhanging vegetation and invertebrate drift density. Our study suggests that fish resource use patterns need to be understood in the context of multiple interacting ecological factors, including prey abundance.

Ichthyofauna of Mundaú river basin, Ceará State, Northeastern Brazil

Abstract Mundaú river basin is located at Center-North Ceará State and occupies a total area of 2,227 km2, including Estuário do Rio Mundaú Environmental Protection Area. This study aimed to catalog the fishes of this basin. Collections were performed with active and passive gear in 35 sampling sites, between 2012 and 2014, in several habitats (main channels, streams, floodplains, permanent and temporary pools, ponds, and dams). A total of 2,545 specimens were collected, belonging to 55 species distributed in 10 orders, 31 families, and 50 genera; 30 of these are strictly freshwater species, and 25 estuarine-marine species. Three species (Hemigrammus guyanensis Gery, 1995, H. rodwayi Durbin, 1909 and Poecilia sarrafae Bragança & Costa, 2011) represent new records for the Mid-Northeastern Caatinga ecoregion. Besides, two cynolebiid species, Hypsolebias sp. and Anablepsoides cearensis (Costa & Vono, 2009), were found and the latter, currently classified as critically endangered, had its occurrence area widened.

Description of a previously unknown population of an endangered desert fish, Poeciliopsis occidentalis occidentalis

Abstract We report a previously unknown population of Poeciliopsis occidentalis occidentalis in La Barge Creek, a tributary stream to the Salt River in Arizona. The population inhabits a slick rock canyon with four permanent pools of water. Previous translocation efforts for P. o. occidentalis occurred more than 7 km upstream of the described location in Charlebois Spring; however, this species has not been observed at the translocation site recently. It is possible that the LaBarge Creek population emigrated from Charlebois Spring. Additional sampling is necessary to determine the source of this population.

Lane bias in elite-level swimming competition

ABSTRACTPerformance outcomes at the 2013 World Swimming Championship were previously shown to be biased depending on the swimmer’s lane assignment. The purpose of this study was to determine if this kind of bias was unique, and if not, if the bias was related to the temporary or permanent nature of the pool. The effect of lane on the average odd-length split minus the preceding even-length split in the 800- and 1500-m freestyle events, and on the relative change from qualifying to preliminary performance in the 50-m events, was determined for 16 other elite-level competitions. Depending on the swimmers’ direction, split times were on average 0.16 s slower or faster in at least one lane at each of the 16 competitions, and in 49% of all lanes analysed. In 5 competitions, swimmers were shown to be faster in a majority of lanes in one direction as compared to the other. Analysis of the 50-m events at these 5 competitions indicate that preliminary performances were between 0.5 and 0.9% slower or faster than qualifying times, which is consistent with the direction effect observed in the distance freestyle events. Further, lane biases occur more often in temporary pools (70% of lanes) than in permanent pools (35% of lanes), with water currents as the most plausible cause. The prevalence of lane bias at elite-level swimming competition highlights the need for the implementation of policies and procedures to prevent such bias from occurring again in the future.

Do cytokinins, volatile isoprenoids and carotenoids synergically delay leaf senescence?

Do cytokinins, volatile isoprenoids and carotenoids synergically delay leaf senescence?

Summer die-off of western pond turtle (Actinemys marmorata) along an intermittent coast range stream in central California

Abstract During late summer and fall 2014, we documented western pond turtle (Actinemys marmorata) mortality, as indicated by the presence of turtle shells, along a 3.7-km reach of Coyote Creek in the Diablo Range of central California. In total, we observed 39 western pond turtle shells scattered irregularly along our study reach. Shells were found in dry reaches adjacent to or close to pools containing live turtles, as well as in or adjacent to dry pools in isolated dry reaches. Ninety percent of shells observed contained no carcass, and several shells showed evidence of predation. Though the cause of mortality is unclear, our observations confirm that western pond turtles may experience high mortality during droughts, which could result in significant population decline. The presence of live turtles in refugial pools emphasizes the importance of protecting and managing permanent pools in the face of intensified drought conditions.

Go with the flow: the movement behaviour of fish from isolated waterhole refugia during connecting flow events in an intermittent dryland river

Summary In many intermittent, dryland rivers, fish are confined to isolated waterholes for much of the year. It is only during brief flow events, which typify the hydrology of these systems, that fish are able to move between waterholes and explore surrounding habitat. Because most of the river channel will dry afterwards, there is a strong advantage for selection of persistent waterholes. Two hundred and fifteen individual fish of three common large‐bodied species were tagged in two isolated waterholes in the Moonie River (Queensland, Australia) over 3 years. Their movements were monitored to identify the flow events that trigger fish movement between waterholes, differences in response among species and size classes and refuge selection preferences. Some individuals of all species moved during flow events and others remained within the same waterhole. There was no clear upstream or downstream preference, and most individuals used a reach of up to 20 km, although some individuals ranged over more than 70 km in only several days. Above a threshold flow of 2 m above commence‐to‐flow level, timing of flow was more important than magnitude, with most movement occurring in response to the first post‐winter flow event, independent of its magnitude and duration. Many of the fish that moved displayed philopatry and subsequently returned to their starting waterhole either by the end of a flow event or on subsequent events, suggesting ability to navigate and a preference for more permanent refuge pools. Maximising survival in a highly variable environment provides a plausible mechanism for maintaining these behaviours. Modifications to both flow regime and hydrological connectivity may reduce movement opportunities for fish in intermittent rivers. Our findings show that fish in intermittent systems use networks of waterholes and that management and conservation strategies should aim to maintain movement opportunities at large spatial scales to preserve population resilience.

Fish functional groups in a tropical wetland of the Yucatan Peninsula, Mexico

ABSTRACT The characterization of species' functional traits is a major step in the understanding and description of communities in natural habitats. The classification of species into functional groups is a useful tool to identify redundancy and uniqueness. We studied the fish community of a pristine freshwater wetland in the Sian Ka'an Biosphere Reserve by analysing two multidimensional functions: food acquisition and locomotion. We investigated changes in the functional group structure between habitats (permanent and temporary pools) and seasons (dry and wet). Six functional groups with different ecological characteristics were detected, two of which had high functional redundancy and three of them were represented by single species with unique ecological functions. In permanent pools during the dry season, functional group richness and diversity were lower, while evenness was higher. During the wet season, all functional groups were detected and similar functional group structure was found between habitats. These results suggest an effect of environmental filtering during the dry season and niche complementarity during the wet season.

Influence of Physical Manipulations on Short-Term Salt Marsh Morphodynamics: Examples from the North and Mid-Atlantic Coast, USA

Along the mid- and north Atlantic coasts of the USA, over 90 % of salt marshes have been ditched. Ditching was largely abandoned by the mid-twentieth century; however, techniques that create permanent shallow water pools for mosquito control and bird habitat are increasingly being applied to marshes of the USA and elsewhere. Salt marshes in Plum Island Sound, Massachusetts, and Barnegat Bay, New Jersey, were used to examine differences between areas that have been ditched and those altered to increase the density of shallow pools in water table dynamics, salinity, soil and porewater chemistry, as well as short-term sedimentation, accretion, and elevation change rates. We found that the area with plugged ditches, berms, and pools in Plum Island had less drainage, higher salinity and porewater sulfide and ammonium concentrations, and higher soil organic matter than the adjacent ditched area. Despite averaging 8 cm lower in elevation, the Plum Island ditched area had less sediment deposition and was composed of higher elevation plant species than the area with plugged ditches, berms, and shallow pools. Elevation increased in the ditched area at a rate of 3.2 ± 0.5 mm/year, but elevation change was variable in the area with pools. In Barnegat Bay, the marsh area with pools and ditches had less sediment deposition and surface accretion than the ditch-only area, associated, in part, with the higher elevation. An average elevation difference of 4.5 cm was associated with a sixfold difference in mineral sediment deposition. Temporal sediment deposition and surface accretion was important in the ditch-only area but was absent or muted in the area with numerous pools. Elevation increased in both marsh areas at an average rate of 1.8 ± 0.8 mm/year, less than half the long-term average local rate of sea-level rise. Our results illustrate how physical manipulations including changes to tidal hydrology and surface topography interact with elevation to influence short-term biophysical feedbacks.

Effect of open water pools on ecosystem scale surface-atmosphere carbon dioxide exchange in a boreal peatland

Peatland carbon dioxide (CO2) exchange can vary spatially over a few meters because of the heterogeneity in plant communities, differing responses to environmental conditions, and the presence of pools in patterned peatlands. In contrast to the plant communities comprising a peatland’s vegetated surface, permanent pools that are characteristic of peatlands in temperate to subarctic regions are net sources of CO2 to the atmosphere. Measurements of net ecosystem CO2 exchange using the eddy covariance (EC) technique over peatlands without permanent pools do not show the smaller plant scale spatial heterogeneity in fluxes because the atmosphere mixes the variations in fluxes over the EC tower source area. However, if different vegetation communities and pools approach the spatial scale that they form a significant proportion of an EC tower’s source area, such as might be the case in peatlands with pools, they should be able to be discriminated if the surface fluxes by cover type are significantly different. In the present study, we evaluate if the observed variability in peatland surface CO2 exchange can be identified from 30-min net ecosystem CO2 exchange measurements using the proportion of the different plant communities or pools within the eddy covariance tower source area. Our results show that the variability in CO2 exchange at the local scale across the peatland surface has a measureable impact on the ecosystem level measurement, primarily when open water pools are present within the tower source area. Our results also suggest that large CO2 exchange rates measured above Sphagnum spp. hummocks with Picea mariana, combined with their large fractional contribution to the source area, counterbalanced the CO2 loss from the open water pools, explaining why the ecosystem as a whole was a net CO2 sink during the measurement period.

Pan floor ‘barchan’ mounds, Ntwetwe Pan, Makgadikgadi, Botswana: Their origin and palaeoclimatic implications

The variety of forms, assumed to be dunes, and palaeolakes of northern Botswana have long been perceived as geoproxies for the elucidation of Quaternary palaeoclimates. Mounds on the floor of Ntwetwe pan have been regarded as modified barchans, pertaining to a time in the past when conditions were drier than at present. The morphology, hydrogeology, and biology of these, placed in the wider context of the palaeolacustrine hinterland, indicate that they are not dunes but subaqueous features, spring mounds. The morphology is inconsistent with barchans. Conspicuous features are the elevated ‘eyes’ within the enclosing arms of the crescentic forms that occur furthest from the pan edge. Seepages discharge from their flanks, commonly about 7 m higher than the dry, saline pan floor. On the top of forms nearer the pan margins, permanent pools of potable water occur, similarly elevated above the floor. Hydraulic pressure to sustain the upward discharge of groundwater is provided by the excellent recharge through silicate karst depressions in the hinterland, particularly those of the 936 m palaeolake floor. Groundwater discharge, still operating today, was formerly much stronger and associated with lacustrine conditions. A chronological framework is provided by archaeological remains on the palaeolake floors of the hinterland. These indicate that the oldest palaeolake floor pertaining to the Quaternary is the 920 m level. Periods of spring mound formation are associated with both this and the 912 m palaeolake. The implications for future luminescence dating targeting palaeoenvironmental reconstruction are discussed in the light of this new model of mound formation.

Multiple environmental stressors increase the realised niche breadth of a forest‐dwelling fish

Understanding the determinants of species' niche breadth is important due to the negative relationship between niche breadth and extinction probability. Species tolerant to extremely harsh abiotic conditions (e.g. low pH or hypoxia) often have relatively small realised niches due to a trade‐off between abiotic and biotic stress tolerance, and are therefore particularly vulnerable to extinction. We hypothesised that tolerance to multiple extreme conditions (e.g. low pH, hypoxia and drought) in brown mudfish Neochanna apoda, would increase their realised niche breadth because each extreme would provide additive refuge against a dominant species, the banded kokopu Galaxias fasciatus. Fish distributions were surveyed in 65 peat‐swamp‐forest streams and pools in New Zealand, which varied in dissolved oxygen, acidity and hydroperiod. Mudfish distribution was extremely patchy, and almost completely allopatric with kokopu. Allopatry was driven mainly by pool hydroperiod; mudfish occupied 88 percent of temporary pools due to their tolerance of habitat drying, whereas kokopu were absent from temporary pools. Within permanent pools, mudfish occurrence was negatively related to pool oxygen and pH, whereas kokopu occurrence was positively related to these conditions. Pool conditions were independently distributed in the landscape, suggesting that each abiotic stressor offered additive refuge for mudfish from kokopu predation/competition. Consequently, the mudfish realised niche breadth depended on the number of abiotic factors driving their allopatry with kokopu. Given the widespread negative relationships between niche breadth and species extinction probabilities, our results indicate that tolerance to multiple stressors may play an important role in insuring species persistence against the multiple drivers of global environmental change.

Distribución geográfica y ecológica de la nutria de río neotropical (Lontra longicaudis) en Michoacán, México

Introduction: Considering the general deterioration of Michoacan rivers, increased poaching, the failure to enforce relevant laws in the last 10 years, and the absence of a detailed assessment of the current status of the river otter (Lontra longicaudus) in the state of Michoacan, our main goal was to collect and analyze all available historical and recent evidence for the occurrence of the river otter in this state. The study focused on three regions for which field recordings were obtained during the period 2005 to 2012. Our second objective was to analyze the ecological conditions associated with these recent records. This information is especially important because the species is protected in Michoacan, and it is an indicator of the environmental quality of water bodies. Methodology: Historical records of otters in Michoacan were reviewed to establish their reliability and age. The search included scientific papers, theses, and data bases of scientific collections available on line. The current presence of river otters in the state was further documented by diurnal transects along rivers and streams in which visual records, footprint tracks, feces, burrows, latrines, or skulls were obtained. The records were then projected on maps in order to analyze them in the context of biogeographic regions, watersheds, vegetation-types, climate, cities, and rivers. Results: The presence of river otters in Michoacan was documented by only 10 historical records (Fig. 1, Table 1). Our field work generated 90 records in 17 localities (Fig. 2, Table 1). The records were found in four watersheds. The type of vegetation that is associated with the largest number of records was the tropical deciduous forest (n = 47, 52%), which is characterized by average temperatures between 21 and 28 ⁰C and annual rainfall between 700 and 1,300 mm. Discussion and conclusions: Our results represent the most recent records for L. longicaudus for the state of Michoacan, and perhaps for any other state in central-western Mexico. The observed distribution of the river otter confirms its presence in at least three major biogeographic regions of Michoacan, namely Balsas, Sierra Madre del Sur, and Pacific Coast. All the data obtained during the study associate this species with perennial streams and where permanent pools remain during the dry season (Fig. 1). This area may be an important refuge for this species because a hydrological network is spread over environmental heterogeneity encompassing temperate forests in the Sierra Madre del Sur and the Eje Neovolcanico to tropical deciduous forests along the Balsas River and the Pacific coast. In the future, it will be important to document if this otter occurs in the Zicuiran-Infiernillo Biosphere Reserve which seems to have the potential for connectivity with rivers in the state of Guerrero. This would make the Michoacan otters of considerable importance for conservation programs on a regional level.

Divergence in threat sensitivity among aquatic larvae of cryptic mosquito species

Predation is a major evolutionary force driving speciation. The threat-sensitive response hypothesis predicts that prey adjust and balance the time spent on a costly antipredator response with other activities that enhance their fitness. Thus, prey able to develop an antipredator response proportional to risk intensity should have a selective advantage. Knowledge on how evolution has shaped threat sensitivity among closely related species exposed to different predation pressures is scarce, prompting investigations to better predict and explain its effect on communities. We explored and compared the antipredator response of aquatic mosquito larvae in three sibling species of the Anopheles gambiae complex, with contrasting larval biologies in Burkina Faso. Anopheles arabiensis and An. gambiae sensu stricto breed in temporary water collections where predator densities are low, whereas Anopheles coluzzii is able to thrive in permanent pools where the predation pressure is much higher. We hypothesized that the increase and decline of behavioural antipredator responses might differ between the three species over time. To test this hypothesis, progenies of field-collected mosquitoes were experimentally exposed to a range of soluble predation cues and their response was monitored for up to 48 h. The three species were all threat sensitive but their reaction norms differed. For the range of concentrations tested, An. coluzzii larvae gradually increased in antipredator response, whereas An. gambiae larvae readily displayed antipredator behaviour at low concentrations leading to a saturation of the response for high cue concentrations. An. arabiensis displayed a narrower reaction norm with low response intensity. Larval instars did not differ in their threat sensitivity. The antipredator behaviour of the three species waned after about 1 h of exposure. Early instars tended to express antipredation behaviour for longer than did older instars. This study provides information on how aquatic prey species with an aerial adult stage manage larval predation risk over time according to cue concentrations and suggests that different predation pressures might play a role as a disruptive selective force fostering habitat segregation and speciation within the An. gambiae complex. The evolution of phenotypic plasticity is further discussed in the light of divergent predation pressures.

Fish diet composition in permanent and semi-permanent pools in tropical wetlands of the Yucatan Peninsula

We compared fish diet composition between permanent (P) and semi-permanent (SP) pools in Petenes Biosphere Reserve (PBR), Campeche. A total of 445 gut contents were examined to determine stomach relative fullness (RF), fish diet as index of niche breadth (INB) and diet overlap. In SP pools, species showed a RF of 1.66 (57.20 % empty stomachs) whereas in P pools, the RF was 2.91 (31.16%). We classified fish diet into six trophic groups: detritivorous, herbivorous-detritivorous, insectivorous, piscivorous, omnivorous and malacophagous. Species in P pools were found to be specialist. Conversely, species present in both habitats shifted to generalist patterns. There was a 54.0% dissimilarity in fish diet composition between pools. From all items identified, detritus (21.33% of the total dissimilarity), aquatic and terrestrial invertebrates (12.31%), fish remains (10.29%), plant remains (7.37%), and crustaceans (2.74%) distinguished diets between pools. Significant diet overlaps (>0.6) and low INB values (<0.3) were observed in P pools, whereas in SP pools, intermediate-low diet overlaps (<0.4) and higher INB values (>0.5) were observed. In SP pools seasonality had a strong effect on fish diet, increasing the frequency of food items such as terrestrial insects, amphipods and arachnids, during the rainy season while P pools showed lower variation. Thus, fish trophic habits appear to be regulated by pools hydrology.

Ecological correlates between cladocerans and their endoparasites from permanent and rain pools: patterns in community composition and diversity

Water fleas (Cladocera) constitute a major component in freshwater food webs, with important ecosystem-level consequences. Their abundance and richness are strongly influenced by their ecology and coevolution with numerous endoparasites. We investigated how parasitism shapes cladoceran community structure and diversity. We surveyed 204 freshwater permanent and rain pools in Israel, identified all cladoceran specimens and screened them for infection. Daphniid species richness in this survey was lower than in previous surveys and the distribution pattern of the species was different, most likely due to local extinction and habitat loss. We recorded a total of 21 taxa of endoparasites, of which 13 are most likely species not yet described. Variation in parasite richness among hosts and sites could not be attributed to differences in host body size and behavioral feeding strategies. We extend the known host range and geographic distribution of eight parasites from Europe and North America (between latitudes 40° and 70°) to much southern areas (latitudes 31° and 32°) and to different climate zones (arid and semi-arid areas). In many infected populations we found co-occurrence of at least two endoparasites, and in most of these cases Daphnia individuals were found to be infected by several endoparasite species simultaneously. Such multiple infections may have important consequences for community structure as well as host–parasite coevolution.

Composition and structure of macroinvertebrate communities in contrasting open-water habitats in Irish peatlands: implications for biodiversity conservation

The purpose of this study was to consider the relative importance of several habitat variables in explaining the patterns in the structure of macroinvertebrate assemblages in open-water habitats, in relatively intact bogs and fens, which should inform conservation strategies. It was hypothesised that variables relating to the size of the water body would differentiate the communities and that some species would be unique to certain conditions. The macroinvertebrate communities from pools >100 m2, 10.1–100 m2 and Sphagnum hollows were characterised using sweep sampling for eight intact peatland sites across four bog types, and related to habitat variables including pool size, Sphagnum cover and hydrochemistry. Results showed community composition and structure differed significantly between deep, permanent pools and shallow, drought-sensitive Sphagnum hollows, with larger invertebrates, such as Odonates and Dytiscinae, rarely found in the hollows. Sphagnum cover accounted for a substantial amount of the variation in community composition. An examination of life-history strategies found species dependent on predictable conditions for juvenile development to be more abundant in pools. In contrast, taxa that could delay juvenile development until conditions were favourable were more abundant in Sphagnum hollows. These results highlight the importance of habitat heterogeneity in maintaining macroinvertebrate diversity in peatlands.

Hunting influences the diel patterns in habitat selection by northern pintails Anas acuta

Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California, USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail populations in Suisun Marsh. During 1991‐1993, we radio‐marked and relocated female pintails (individuals: N = 203, relocations: N = 7,688) within Suisun Marsh to investigate habitat selection during the non‐breeding months (winter). We calculated selection ratios for different vegetation types and for sanctuaries, and examined differences in those ratios between hunting season (i.e. hunting and non‐hunting), age (hatch‐year and after‐hatch‐year), and time of day (daylight or night hours). We found that diel patterns in selection were influenced by hunting disturbance. For example, prior to the hunting season and during daylight hours, pintails selected areas dominated by brass buttons Cotula coronopifolia, a potentially important food source, usually outside of sanctuary boundaries. However, during the hunting season, pintails did not select brass buttons during daylight hours, but instead highly selected permanent pools, mostly within sanctuaries. Also, during the hunting season, pintails showed strong selection for brass buttons at night. Sanctuaries provided more area of permanent water pools than within hunting areas and appeared to function as important refugia during daylight hours of the hunting season. Wildlife managers should encourage large protected permanent pools adjacent to hunted wetlands to increase pintail numbers within wetland environments and responsibly benefit hunting opportunities while improving pintail conservation.

Temporal variation of β-diversity and assembly mechanisms in a bacterial metacommunity

The turnover of community composition across space, β-diversity, is influenced by different assembly mechanisms, which place varying weight on local habitat factors, such as environmental conditions and species interactions, and regional factors such as dispersal and history. Several assembly mechanisms may function simultaneously; however, little is known about how their importance changes over time and why. Here, we implemented a field survey where we sampled a bacterial metacommunity consisting of 17 rock pools located at the Swedish Baltic Sea coast at 11 occasions during 1 year. We determined to which extent communities were structured by different assembly mechanisms using variation partitioning and studied changes in β-diversity across environmental gradients over time. β-Diversity was highest at times of high overall productivity and environmental heterogeneity in the metacommunity, at least partly due to species sorting, that is, selection of taxa by the prevailing environmental conditions. In contrast, dispersal-driven assembly mechanisms were primarily detected at times when β-diversity was relatively low. There were no indications for strong and persistent differences in community composition or β-diversity between permanent and temporary pools, indicating that the physical disturbance regime is of relatively minor importance. In summary, our study clearly suggests that there are temporal differences in the relative importance of different assembly mechanisms related to abiotic factors and shows that the temporal variability of those factors is important for a more complete understanding of bacterial metacommunity dynamics.

Responses of plants and invertebrate assemblages to water-level fluctuation in headwater wetlands

AbstractFlood-pulsing is a key environmental factor that structures biotic communities in large-order river systems, but we focused our study on the effects of flood-pulsing in headwater systems. We used 10 mesocosm wetlands (10 m × 20 m) to test 2 treatments: a flood-pulse regimen in which natural flood events caused water levels to fluctuate and a static regimen in which water levels remained artificially stable. Abiotic characteristics, plants, and aquatic invertebrate communities were monitored from 2002 through 2005 in permanent pools, nonflooded banks in static wetlands, and intermittently flooded banks in flood-pulse wetlands. The flood-pulse treatment had minimal effects on environmental conditions of permanent pools, and submersed plant and aquatic invertebrate communities in permanent pools were similar in both treatments. This result suggested that resource subsidies from the floodplain to the pools were minimal. However, flood-pulsing caused observable changes to plant communities in the inter...