Vegetation In Ponds Research Articles

A snapshot of mid Eocene landscapes in the southern Central Andes: Spore-pollen records from the Casa Grande Formation (Jujuy, Argentina).

The southern Central Andes-or Puna-now contains specialized plant communities adapted to life in extreme environments. During the middle Eocene (~40 Ma), the Cordillera at these latitudes was barely uplifted and global climates were much warmer than today. No fossil plant remains have been discovered so far from this age in the Puna region to attest to past scenarios. Yet, we assume that the vegetation cover must have been very different from what it looks today. To test this hypothesis, we study a spore-pollen record from the mid Eocene Casa Grande Formation (Jujuy, northwestern Argentina). Although sampling is preliminary, we found ~70 morphotypes of spores, pollen grains and other palynomorphs, many of which were produced by taxa with tropical or subtropical modern distributions (e.g., Arecaceae, Ulmaceae Phyllostylon, Malvaceae Bombacoideae). Our reconstructed scenario implies the existence of a vegetated pond surrounded by trees, vines, and palms. We also report the northernmost records of a few unequivocal Gondwanan taxa (e.g., Nothofagus, Microcachrys), about 5,000 km north from their Patagonian-Antarctic hotspot. With few exceptions, the discovered taxa-both Neotropical and Gondwanan-became extinct from the region following the severe effects of the Andean uplift and the climate deterioration during the Neogene. We found no evidence for enhanced aridity nor cool conditions in the southern Central Andes at mid Eocene times. Instead, the overall assemblage represents a frost-free and humid to seasonally-dry ecosystem that prevailed near a lacustrine environment, in agreement with previous paleoenvironmental studies. Our reconstruction adds a further biotic component to the previously reported record of mammals.

Analisis kelimpahan plankton dan pertumbuhan kerang kepah Polymesoda erosa (Solander, 1786) yang dipelihara pada tambak di Delta Mahakam

This study was aimed to analyze the prospects of development of the This research was aimed to analyze the relationship between plankton abundance and morphometric growth of Mud Clam (Polymesoda erosa). The study was located in an idle brackish water pond in Mahakam Delta, by culturing Polymesoda erosa in small scale. Grouping random design was applied for sampling. Treatment was divided into factor A and B. Factor A is related to shell size: size I (40 – 60,99 mm), II (61 – 80,99 mm) and size III (81 – 100 mm). Factor B is indicating to study location with vegetation (Rhizophora sp) and no vegetation. In order to analyze plankton abundance, a quantitative descriptive analysis was applied, in addition of ANOVA test to analyze the growth. The result indicated that between two study ponds is different. The number of plankton per liter water from vegetated pond has more plankton individual than the sample from non-vegetated pond. The applied treatment on study ponds and shell size determined the morphometric growth and biometric. The growth of shell length is faster than that on height and thickness. The growth of mud clam in vegetated ponds relatively better that the pond without vegetation.

Mangrove species diversity and carbon stock in silvofishery ponds in Deli Serdang District, North Sumatra, Indonesia

Abstract. Harefa MS, Nasution Z, Mulya MB, Maksum A. 2021. Mangrove species diversity and carbon stock in silvofishery ponds in Deli Serdang District, North Sumatra, Indonesia. Biodiversitas 23: 655-662. Mangrove-based silvofishery ponds are promoted as a win-win solution for biodiversity conservation, climate change mitigation as well as income generation for coastal communities. This study aimed to analyze the species diversity and carbon stock of mangrove vegetation in silvofishery ponds in Tanjung Rejo Village, Percut Seituan Sub-district, Deli Serdang District, North Sumatra, Indonesia. Data of the mangrove species were obtained using vegetation analysis, and the potential carbon stock was estimated based on allometric equations of both above- and below-ground tree biomass. For this purpose, plot samples from 22 silvofishery ponds were taken by establishing 5 aligned circular plots, each with a radius of 5.64 m, perpendicular to the coastline and with a distance of 15 meters between their perimeters. The results show that the mangrove species with the highest Importance Value Index (IVI) was Rhizophora apiculata (122.05%), followed by Excoecaria agallocha (42.29%) and Avicennia marina (36.84%), and the lowest IVI was Sonneratia caseolaris (1.48%). Higher IVI values indicate a larger carbon deposit from mangrove vegetation in silvofishery ponds. Our results indicate that mangrove area coverage of 44-80% per hectare in silvofishery ponds can deposit 40-50 tonnes of carbon per hectare and have greater potential carbon stock compared to coverage below 40%. The mangrove management activities with the sylvofishery scheme have a good impact on the community's economy and also maintain the existence of mangroves as carbon storage.

A Macroscopic Approach for Simulating Horizontal Convection in a Vegetated Pond

A macroscopic approach for simulating horizontal convection in a vegetated pond is presented. The generated convective currents are due to the differential radiation absorption between the two regions of the pond, one with emergent vegetation up to the free surface and one without vegetation. The Volume-Averaged Navier-Stokes (VANS) equations are used for the simulation of the laminar, unsteady, two-dimensional horizontal convection. The vegetation effects on the motion of the currents are taken into account through additional resistance terms based on the vegetation porosity and permeability. The Volume-Averaged Energy (VAE) equation is also solved with an additional source term accounting for the absorption of radiation which is based on a one-waveband and a three-waveband radiation model. The model setup is based on Beer’s law whereas the incoming radiation is absorbed from the water column. Three types of vegetation porosities φ varying from 0.75 to 0.97 are examined in investigating the motion of the convective currents within the vegetated area. The case without vegetation (φ = 1.0) is also examined for assessing the effectiveness of the radiation model. The numerical current velocity and the water temperature increase are presented and compared against available experimental data. • Absorption of radiation based on one- and three-waveband attenuation models • Vegetation effects on the characteristics of horizontal convection • Effect of Grashof number on the motion of horizontal convective currents

Between-habitat distributions of pond tadpoles and their insect predators in response to fish presence

Between-habitat distributions of prey shared by multiple predators depend on habitat use by the predators, whose own distributions may interact. We used a large-scale, whole-system natural experiment to examine distributions of anuran tadpoles and insect predators between pond microhabitats with contrasting complexity (open water vs emergent littoral vegetation) in drainable ponds that were either kept fishless or stocked with fish. Total relative densities of insect predators did not significantly differ with respect to the fish status of the ponds. Individual anuran taxa responded variously, but only fish-tolerant Bufo bufo densities were higher in the presence of fish. The densities of both insect predators and tadpoles showed positive interactions between fish presence and the use of complex littoral habitat. The habitat shift to littoral vegetation could be indirectly amplified by fish adverse impact on submerged macrophytes, the main structured microhabitat in open-water areas. Irrespective of mechanisms of fish effects (direct consumption, behavioral deterrence or alteration of habitat conditions), aggregation of both tadpoles and insect predators in littoral vegetation may put tadpoles at greater risk of predation by insects, a potentially important factor of amphibian mortality in waters containing fish.

Human traffic and habitat complexity are strong predictors for the distribution of a declining amphibian.

Invasive species and habitat modification threaten California's native pond-breeding amphibians, including the federally threatened California Red-legged Frog (Rana draytonii). The relative contributions of invasive species, including the American Bullfrog (Lithobates catesbeianus), and of habitat changes to these declines are disputed. I conducted a field study over several years in central California to examine the presence/absence of these two species at 79 breeding ponds to determine the predictive role for occupancy of factors including vegetation, pond characteristics, and measures of human activity. I used a boosted regression tree approach to determine the relative value of each predictor variable. Increased measures of human activity, especially proximity to trails and roads, were the best predictors for the absence of California Red-legged Frogs and California Newts. Historical factors and habitat conditions were associated with the extent and spread of the American Bullfrog. The extent and complexity of aquatic macrophytes and pond surface area were good predictors for the presence of these and other amphibian species. Surprisingly, invasive species played a relatively small role in predicting pond occupancy by the native species. These findings can inform conservation and restoration efforts for California Red-legged Frogs, which apparently persist best in small vegetated ponds in areas of low human disturbance.

Turbidity, Waterfowl Herbivory, and Propagule Banks Shape Submerged Aquatic Vegetation in Ponds.

The aquatic vegetation in nutrient-rich shallow lakes and ponds is structured by the interplay of multiple biotic and abiotic drivers. We tested the contribution of the macrophyte propagule bank and the delayed as well as direct impact of waterbirds on submerged aquatic vegetation in a peri-urban pond system. To clarify the functional hierarchy of predictor variables, effects of herbivorous waterfowl and propagule bank potential were ranked relative to environmental, phytoplankton, and zooplankton indicators. Two aspects of the aquatic vegetation – community composition and total pond-scale cover – were discriminated. Within vegetation communities, phytoplankton biovolume and waterfowl herbivory during summer were linked to low macrophyte abundance, whereas propagule density of angiosperms was positively associated with specific assemblages of submerged macrophytes. High algal biovolume and summer waterfowl grazing seemed to affect maximal pond-scale cover of submerged aquatic vegetation. The presence of waterfowl in cold and spring periods was unrelated to vegetation structure in the consecutive main growth season. In addition, availability of propagules in the sediment did not automatically prompt pond-wide vegetation cover (especially when overruled by high waterfowl densities), nor did it guarantee a position in the submerged macrophyte community. Nonetheless, propagule bank potential was related to the waterbody’s general ecological status, since turbid ponds exhibited impoverished propagule reserves compared to ponds residing in a clear, macrophyte-dominated state. Inadequate recruitment therefore represents a plausible bottleneck for macrophyte establishment. We conclude that phytoplankton-caused turbidity and high waterfowl biomass densities greatly restrict submerged macrophyte abundance. Propagule banks also participate in structuring submerged aquatic vegetation, though a stronger role is reserved for herbivorous waterfowl.

Reconstruction of annual growth in relation to summer temperatures and translocation of nutrients in the aquatic moss Drepanocladus trifarius from West Greenland

Mosses often dominate the submerged vegetation in Arctic lakes and ponds, making them essential contributors to the primary production in these habitats. However, little is known about the factors controlling annual growth of Arctic mosses and their sensitivity to climatic changes. It has been suggested that nutrient translocation occurs in mosses, and that annual growth of mosses therefore depends strongly on weather conditions and less on local environmental conditions. In this study, we examined annual growth of Drepanocladus trifarius ((F. Weber and D. Mohr) Broth.) from two ponds in West Greenland in relation to weather conditions. A reconstruction of annual growth increments from 2009 to 2014 was made in 200 individual mosses, and biomass and length were related to different weather parameters. In addition, we examined whether there would be an indication of nutrient translocation across annual growth segments. We found a positive relationship between mean summer temperature and growth segment length, which indicates the importance of temperature during seasons with sufficient light levels for growth of the D. trifarius. Weather parameters associated with light conditions had no significant effect on growth, which probably reflect that D. trifarius in two shallow ponds were not light limited. The nutrient stoichiometry showed that phosphorus (P) contents in the tissue were low (0.04–0.11% DW), and nutrient resorption efficiencies of P amounted to 11–29%. This suggests that D. trifarius was P limited during its growth season, but appears capable of nutrient translocation across annual segments, possibly to maintain growth in oligotrophic environments. Despite low nitrogen (N) contents (0.94–2.09%), no resorption of N was found, which indicates that D. trifarius was not N-limited in order to sustain growth. In conclusion, this study shows that growth of D. trifarius in small high Arctic ponds are mainly controlled by summer temperatures.

Amphibian decline, pond loss and reduced population connectivity under agricultural intensification over a 38\xa0year period

Habitat loss, together with less obvious land-use changes such as intensified farming practice, can have significant adverse impacts on biodiversity. An important factor in determining the ability of species to cope with such changes is their potential to sustain a populations network by dispersal across the landscape. Habitat quality and structure are particularly important for surface-dwelling species with low dispersal abilities, such as amphibians. To assess this ecological function, ponds in a coastal and typically rural area of northern France were surveyed for amphibians in 1974, 1992 and 2011. These repeated surveys yielded different outcomes for different species groups. Three rare species persisted in more or less specialized habitat types. Two moderately common species declined, but kept strongholds in coastal dunes and associated marshes. Five common species with broad ecological niches remained equally widespread. The Northern crested newt declined markedly and the Midwife toad declined dramatically, as did their breeding habitats in vegetated ponds and cattle drinking troughs. One species, the Moor frog, may have gone locally extinct. A model of relative resistance to amphibian dispersal was created for different landscape types, on a scale from 0 (low resistance) to 1 (high resistance). This generated values of 0.23 for pasture, 0.72 for arable and 0.98 for urban and transport. As pasture declined in the study area, while arable and urban/transport infrastructure increased, amphibian dispersal became more difficult. However, dispersal paths proved difficult to evaluate in a patchy landscape like the one surveyed, due to a paucity of spatial signal. Pond loss is a more tractable reason for the observed amphibian species decline than is the quality of intervening terrestrial habitat matrix. In 2011, 22 newly created ponds had species richness in line with pre-existing ponds and this will have counteracted a dwindling metapopulation structure, indicating that habitat creation/restoration can play a valuable role in conservation. The colonization of new ponds may also prove more informative for gauging the potential for amphibian dispersal in the landscape than the preceding decline.

Free water surface constructed wetlands limit the dissemination of extended-spectrum beta-lactamase producing Escherichia coli in the natural environment

The fates of Escherichia coli and extended-spectrum beta-lactamase-producing E. coli (ESBL E. coli) were studied over a period of one year in a free water surface constructed wetland (FWS CW) with a succession of open water zones and vegetation ponds (Typha or Phragmites), that received the effluent from a wastewater treatment plant. ESBL E. coli were detected and isolated from all sampling areas of the FWS CW throughout the study period. They represented 1‰ of the total E. coli population regardless of the origin of samples. Two main factors affected the log removal of E. coli and of ESBL E. coli: the season and the presence of vegetation. Between the inlet and the outlet of the FWS CW, the log removal of E. coli ranged from 1.5 in the warmer season (summer and fall) to 3.0 in the colder season (winter and spring). The concentrations of E. coli decreased significantly in the vegetated areas during the colder season, but increased in the warmer season, suggesting an effect of the plant growth stage on the survival of E. coli. Among the 369 ESBL E. coli isolates collected during our study, 84% harbored the CTX-M-ESBL type and 55.3% carried bla genes on plasmid DNA. Furthermore, 93% of the ESBL E. coli isolates were multidrug resistant but the proportion of resistant strains did not change significantly along the FWS CW. ESBL E. coli were characterized by MLST analysis using the 7 genes based Achtman Scheme. ESBL E. coli isolated from water, sediments, roots and feces of myocastors collected in the FWS CW and in the recipient river were genotypically related, suggesting persistence and circulation of the ESBL producing E. coli throughout the FWS CW and in the receiving river. Overall, these observations show that FWS CW could be an efficient treatment for ESBL E. coli disinfection of wastewater and could limit their dissemination in the aquatic environment.

Tidal day organic and inorganic material flux of ponds in the Liberty Island freshwater tidal wetland.

The loss of inorganic and organic material export and habitat produced by freshwater tidal wetlands is hypothesized to be an important contributing factor to the long-term decline in fishery production in San Francisco Estuary. However, due to the absence of freshwater tidal wetlands in the estuary, there is little information on the export of inorganic and organic carbon, nutrient or phytoplankton community biomass and the associated mechanisms. A single-day study was conducted to assess the potential contribution of two small vegetated ponds and one large open-water pond to the inorganic and organic material flux within the freshwater tidal wetland Liberty Island in San Francisco Estuary. The study consisted of an intensive tidal day (25.5 h) sampling program that measured the flux of inorganic and organic material at three ponds using continuous monitoring of flow, chlorophyll a, turbidity and salt combined with discrete measurements of phytoplankton community carbon, total and dissolved organic carbon and nutrient concentration at 1.5 h intervals. Vegetated ponds had greater material concentrations than the open water pond and, despite their small area, contributed up to 81% of the organic and 61% of the inorganic material flux of the wetland. Exchange between ponds was important to wetland flux. The small vegetated pond in the interior of the wetland contributed as much as 72–87% of the total organic carbon and chlorophyll a and 10% of the diatom flux of the wetland. Export of inorganic and organic material from the small vegetated ponds was facilitated by small-scale topography and tidal asymmetry that produced a 40% greater material export on ebb tide. The small vegetated ponds contrasted with the large open water pond, which imported 29–96% of the inorganic and 4–81% of the organic material into the wetland from the adjacent river. This study identified small vegetated ponds as an important source of inorganic and organic material to the wetland and the importance of small scale physical processes within ponds to material flux of the wetland.

Influence of substrate water saturation on pesticide dissipation in constructed wetlands.

Constructed wetlands are an effective and practical option for removing pesticide pollution from runoff or subsurface drainage water. The objective of this study was to assess the efficiencies of a ditch with a bundle of straw placed in its centre and a vegetated pond installed in grass cover bands at downstream of a drained plot. The dissipation rates of three herbicides and three fungicides were monitored on four substrates commonly found in constructed wetlands (two soils, sediment and straw). The influence of water content was determined in a sequence of three steps (flooded-unsaturated-flooded) over 120 days. The pesticide dissipation rates observed during the 120 days of incubation ranged from 1.4 to 100%. Isoproturon and 2,4-MCPA (MCPA) showed the highest dissipation rates, which ranged from 61.0 to 100% of the applied quantities during the 120 days of incubation. In contrast, boscalid and tebuconazole showed the lowest dissipation rates, which ranged from 1.4 to 43.9% of the applied quantities during the 120 days of incubation. The estimated DT50 values ranged from 20.5 days to more than 1 year and were influenced by the substrate water content. The soil and straw substrates had the lowest DT50 values during the unsaturated conditions, whereas the sediments had the lowest DT50 values during the flooded conditions. These results could be explained by an adaptation of microbial communities to their environmental conditions. Thus, the most favourable conditions of dissipation for soils and straw are observable when the drainage ceases (spring and summer). However, favourable conditions occur all year for the sediments, except when the constructed wetlands are dry. The results suggest that the dissipation of pesticides in constructed wetlands contributes to the long-term effectiveness of these buffer zones for reducing water pollution.

Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Abstract - Aquatic herbicides are applied to control nuisance vegetation in lakes and ponds, and are often re-applied over many years. This study compared the abundance of 5 frog species in treated and untreated lakes in Ashburnham, MA. At each lake, I assessed the density of human housing and lake area to determine their relationship with frog abundance. I employed a standard calling index to estimate the abundance of each frog species and the sum of calling indices from all species served as a measure of total frog abundance at each survey site. The sum of calling indices declined with increasing density of human housing; herbicide treatment was not an important main effect. However, there was marginal interaction between herbicides and housing density: lakes with moderate—high housing densities seemed to have lower frog abundance with herbicide treatments. Although the data set was limited, my results suggest that frogs may benefit from permanently untreated refuge zones on lakes. When I assessed frog ...

Artificial irrigation ponds and sea coast as foraging habitat for larids breeding in protected wetlands

Questions related to the preservation of foraging sites of breeding birds have received little attention, although they can be of major importance for population persistence. Here, we used stable isotopes and field observations to evaluate the relative importance of man-made irrigation ponds as foraging areas for a larid community of conservation concern. We also studied the habitat preferences of the bird species and determined whether pairs of species co-occurred or avoided each other while foraging. Six species used marine habitats preferentially, whereas three species preferred freshwater habitats, the latter being provided mainly by irrigation ponds. Larids foraged preferentially in large and vegetated ponds located close to the breeding areas, and avoided sandy areas at the coast. We propose that the European Union subsidies related to the creation and alteration of irrigation ponds should be linked to management strategies that maximise pond quality for waterbirds. A third of the species pairs examined showed strong support for the species co-occurring more often than expected by random. Our study showed that larids breeding in mixed colonies segregate spatially in their foraging niche between marine and freshwater environments. Both breeding and foraging habitats need to be addressed when analysing larid population dynamics and conservation strategies.

Can submerged macrophytes be effective for controlling waterborne phytopathogens in irrigation ponds? An experimental approach using microcosms

Irrigation ponds may act as a source of phytopathogenic species that might infest crops through the irrigation systems. Many studies have shown that submerged macrophytes can improve water clarity by out-competing phytoplankton by means of various mechanisms: favoured phytoplankton-grazing zooplankton, reduced nutrient and light availability, increased sinking losses and the release of allelopathically active substances. However, less information is available on the effects of submerged macrophytes on heterotrophic aquatic organisms such as pathogenic bacteria, fungi or oomycete species. This paper studies the effects of three submerged macrophytes—Chara fragilis, Potamogeton pectinatus and Najas marina—on the viability in water of propagules of two phytopathogenic isolates of the oomycetes Pythium aphanidermatum and Pythium ultimum. Moreover, we tested general antimicrobial properties (against bacteria and fungi in water) for these macrophytes. The results showed clear inhibitory effects of all three macrophytes on bacterial density in water and of C. fragilis on the viability of Pythium. Thus, preserving aquatic vegetation in irrigation ponds (i.e. charophytes), besides its purely environmental interest, may have important agronomic benefits owing to their role as biological control against some phytopathogenic agents.

AN EXPERIMENTAL EVALUATION OF SUSTAINABLE DRAINAGE SYSTEMS

This paper investigates the behaviour of certain water and sediment quality indicators of a vegetated detention pond system located at Waterlooville, Hampshire, UK. The period of study was 2 years (March 2011-March 2013) with sampling carried out once a month. Statistical analysis was performed using Minitab™. The aim of the study was to examine the changes in quality of various constituents with time and possible linear associations between them. Pond sediments and pond water quality were monitored for a range of variables at each monthly visit. Results indicate that the system demonstrates low levels of pollution while not having a direct impact on the oxygen balance of the receiving water-body. Oxygen demanding substances along with suspended matter and certain metals/elements were found to accumulate in the system with time. Significant linear associations were observed for road salts (containing Na, Cl, Mg) and certain pollutants, suggesting that road salts have a major impact on SuDS water/sediment quality. Sorption characteristics of specific metals were also evaluated by means of adsorption isotherm equations. Three widely used sorption isotherms were employed in this study. It was found that the sorption behaviour of metals is highly variable. This study highlights the dynamic nature of vegetated ponds and the importance of understanding the behaviour of different pollutants for SuDS design.

AN EXPERIMENTAL EVALUATION OF SUSTAINABLE DRAINAGE SYSTEMS

This paper investigates the behaviour of certain water and sediment quality indicators of a vegetated detention pond system located at Waterlooville, Hampshire, UK. The period of study was 2 years (March 2011-March 2013) with sampling carried out once a month. Statistical analysis was performed using Minitab™. The aim of the study was to examine the changes in quality of various constituents with time and possible linear associations between them. Pond sediments and pond water quality were monitored for a range of variables at each monthly visit. Results indicate that the system demonstrates low levels of pollution while not having a direct impact on the oxygen balance of the receiving water-body. Oxygen demanding substances along with suspended matter and certain metals/elements were found to accumulate in the system with time. Significant linear associations were observed for road salts (containing Na, Cl, Mg) and certain pollutants, suggesting that road salts have a major impact on SuDS water/sediment quality. Sorption characteristics of specific metals were also evaluated by means of adsorption isotherm equations. Three widely used sorption isotherms were employed in this study. It was found that the sorption behaviour of metals is highly variable. This study highlights the dynamic nature of vegetated ponds and the importance of understanding the behaviour of different pollutants for SuDS design.

Efficacy and Physiological Responses of Grass Carp to Different Sedation Techniques: I. Effects of Various Chemicals on Sedation and Blood Chemistry

AbstractGrass carp Ctenopharyngodon idella are commonly used as a low cost, biological control for aquatic vegetation in aquaculture ponds and other private and public waters. In order to minimize the risk of establishing self‐sustaining populations in U.S. waters, many states now require grass carp be certified as triploid prior to sale and stocking. To facilitate ploidy testing, grass carp are typically sedated before collecting blood samples. Chemical sedatives such as tricaine methanesulfonate (MS‐222) and carbon dioxide (CO2) are most commonly used to sedate fish, but there is increasing interest in other chemical sedatives such as benzocaine and eugenol. We evaluated time to induction to Stage IV sedation and recovery, survival, and postsedation blood chemistry of grass carp (301 ± 8 g, mean ± SE) sedated with MS‐222 (150 mg/L), benzocaine (150 mg/L), eugenol (60 mg/L), or CO2 (∼400 mg/L). Induction times for all sedatives excluding CO2 (14.9 min) were less than 2.4 min (range, 1.5–2.4 min). Average recovery time after induction was 5.8 min (range, 2.8–8.3 min) excluding benzocaine, which had a recovery time of 15.4 min. Survival was high and unaffected by sedative option. Plasma cortisol and lactate levels peaked between 0.5 and 1 h postinduction before returning to resting levels at 6 h postinduction. No obvious changes were observed in blood glucose or hematocrit. Each of the sedatives was effective in sedating grass carp, and though changes in blood chemistry indicated that an acute stress response occurred, the response was transient. Although each of the evaluated sedatives would facilitate ploidy testing, some strategies may be more appropriate than others based on FDA approval status and access to the sedative compound, handling time, withdrawal period, and on‐site conditions and resources.

Dependence of anuran diversity on environmental descriptors in farmland ponds

In the Neotropics, conversion of natural habitats into agricultural areas is occurring at a high rate, with consequent reduction of habitat complexity in anuran breeding ponds. Identifying features of farmland ponds that allow them to support a high diversity of species is fundamental for successful management and conservation policies and is especially important in Neotropical regions that harbor the highest anuran species richness in the world. Here, we aimed to investigate which environmental descriptors correlate the occurrence of anuran species in tropical farmland ponds in southeastern Brazil. We found that environmental descriptors reflecting the complexity of vegetation in farmland ponds primarily predict the diversity of anuran species in these habitats. Species richness was correlated mainly by vegetation height in the margin, with ponds that exhibit greater stratification harboring a larger number of species. Vegetation height in the interior of ponds, diversity of vegetation in the margin, pond area and hydroperiod were also important variables predicting the abundance of six of 10 anuran species analyzed. Our results show that features of farmland ponds representing increased habitat complexity are key factors in maintaining a high diversity of species, providing a greater variety of microhabitats, both in vertical and horizontal strata, and thus meeting diverse species-specific requirements.

EDITORIAL

Over the last few months I have been comparing the way in which flood risk is managed in major cities around the world. In particular I have sought to distinguish how communities, and their governments, respond to the two ends of the flood spectrum, that is, the frequent but less severe flood events, and the rare but extreme events. Most countries invest in managing flood risk across the spectrum. Traditional solutions to frequent flooding often involve improved drainage conveyance or local channel realignment works, while extreme events are dealt with by building flood defence structures. Risk in both categories is growing however, despite this investment. This is mainly due to the effects of increasing urbanisation and increased rainfall intensity as a result of climate change. In addition many urban areas suffer from the process of urban creep, that is, the infill of open space with new development and the extension of existing building footprints. Urban creep is typically increasing paved areas at a rate of between 0.25% and 2.5% per annum. So over the last 30 years some paved areas will have doubled in size, even though population may have remained static. Climate change could increase rainfall intensities by up to 40% in some areas. Existing drainage infrastructure cannot cope with such changes, and investment in increasing infrastructure capacity has lagged well behind the growth in need. This is leading to a significant increase in the frequency of more modest flood events and substantial increases in devastation from extreme events. The challenge therefore is how to reverse this trend. Planning restrictions and building regulations can help to limit further urban creep, but many countries now accept that more sustainable approaches to draining urban development need to be found. There has been significant progress in implementing sustainable drainage measures (sometimes referred to as best management practices) to limit run-off from new development. But there is little evidence of progress on retrofitting such measures, and in particular creating safe flood pathways for managing extreme events. The more notable exceptions to this are in Holland and parts of Sweden and the United States where innovative approaches to retrofitting have resulted in the disconnection of existing roof areas to be drained locally, and the creation of designated flood pathways using roads and sacrificial flood areas in parks and open space. Such innovation can do much to reduce flood risk without the need for investment in heavy infrastructure. These new methods differ substantially from traditional infrastructure. They are more closely related to natural drainage, using vegetated ponds and channels and mimicking natural systems. They need to be more carefully integrated into the urban landscape but they can deliver benefits beyond those of flood risk management (improved water quality, amenity and bio-diversity). The skills needed to progress such innovation extend beyond those of engineers to include architects, planners and social scientists. It is yet another example of the great benefits that can be realised from interdisciplinary approaches to flood risk management.