Permanent Wetlands Research Articles

Temporal distribution of crustaceans in forested freshwater wetlands: responses to changes in the hydroperiod

Studies on crustacean communities in Chilean wetlands are scarce. The aim of this study was to characterize the crustacean community in forested wetlands from southern Chile and to establish their relation with the variations in the hydrological regime. In total, 540 samples were taken using three complementary sampling techniques in five wetlands during 2011 and 2012. The results show a total of four species of crustaceans, of which the amphipod Hyalella patagonica (Cunningham, 1871) (Hyalellidae) was dominant in ephemeral wetlands and the isopod Heterias exul (Mueller, 1892) (Janiridae) in permanent wetlands. The other species (the decapods Parastacus pugnax (Poeppig, 1835) (Parastacidae) and Aegla araucaniensis (Jara, 1980) (Aeglidae)) showed abundances below 6% in all wetlands. The identified crustaceans presented marked variations, both at a temporal scale and between wetlands with different hydrological regimes, both at the species level and at the crustacean community level. These patterns were mainly explained by changes registered in the annual hydroperiod and our results conform to the existing information that would indicate the importance of the inclusion of hydrological patterns in descriptions of freshwater communities.

若尔盖高原湿地泥炭沼泽土亚硝酸盐还原酶（nirK）反硝化细菌群落结构分析

PDF HTML阅读 XML下载 导出引用 引用提醒 若尔盖高原湿地泥炭沼泽土亚硝酸盐还原酶（nirK）反硝化细菌群落结构分析 DOI: 10.5846/stxb201607151442 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41201256）。 Analyzing the nitrate reductase gene (nirK) community in the peat soil of the Zoige Wetland of the Tibetan Plateau Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:若尔盖泥炭湿地是世界少有的低纬度永久冻土湿地，具有高海拔、高紫外辐射、高有机质的特点。该区域N2O的排放量对全球气候变暖有重要影响。对若尔盖高原湿地泥炭沼泽土中的亚硝酸盐还原酶（nirK）反硝化细菌群落结构多样性进行分析，以期揭示该区域N2O释放的微生物调控机制。基于若尔盖高原湿地泥炭沼泽土的理化性质和反硝化活性（PDA），结合限制性酶切片段长度多态性（Restriction fragment length polymorphism， RFLP）技术、克隆文库及分子测序对该生态系统中的nirK反硝化细菌群落结构及多样性进行分析。反硝化活性测定结果显示：阿西地区>麦溪地区>分区地区，反硝化活性与土壤有机碳、总氮和丰富度呈显著正相关（P < 0.05）。Shannon-wiener多样性指数以阿西最高、分区最低。3个样品中共测序15条nirK基因代表序列，系统发育表明若尔盖高原湿地优势nirK反硝化菌群为变形门菌群。其中，阿西地区主要为α-变形菌门，麦溪地区主要为β-变形菌门，分区地区无法确定优势种群。冗余分析（Redundancy analysis， RDA）显示：有效钾和有效磷是影响nirK反硝化细菌群落结构的关键环境因子。本论文显示，若尔盖高原湿地存在着明显的反硝化作用，调控这些反硝化作用的nirK反硝化细菌多样性较高，且与土壤有效钾和有效磷密切相关。 Abstract:The Zoige Wetland, which is located in the northeast of the Tibetan Plateau, is a typical low latitude permanent permafrost wetland, with high altitude intensive ultraviolet radiation and high soil organic matter content. The nitrous oxide fluxes in this area are critical to global warming. The main objective of this study was to elucidate the diversity and structure of the nitrate reductase (nirK) gene denitrifier community, and to further explore the microbial mediated mechanism of N2O release in this climatically extreme area. Based on the soil physicochemical properties and denitrifying activity (PDA) analysis, restriction fragment length polymorphism (RFLP), clone library and sequencing were further used to analyze the diversity and structure of the nirK gene in the denitrifier community. The results showed that the highest activity of PDA was detected in the Axi soil, while the lowest activity was in the Fenqu soil. The PDA was significantly and positively correlated with soil organic carbon, total nitrogen and nirK gene richness (P < 0.05). The highest and lowest Shannon-Wiener diversity indices were detected in Axi and Fenqu soils, respectively. Based on the RFLP patterns, 15 different nirK gene clones were selected for sequencing and further phylogenetic analysis. The phylogenetic analysis showed that the majority of the nirK-denitrifiers in the peat soil of the Zoige Wetland belonged to Proteobacteria, and the dominant species in the Axi soil were Alphaproteobacteria, whereas Betaproteobacteria species dominated in the Maixi soil. The dominant nirK denitrifiers remained unidentified in the Fenqu soil. Redundancy analysis (RDA) was used to explore the possible relationship between the nirK denitrifiers community and soil physicochemical parameters, and the results showed that soil available potassium and available phosphorus were the two most important factors in shaping nirK denitrifier communities. In conclusion, the current study revealed obvious denitrifying activities in the Zoige Plateau Wetland. The nirK gene denitrifying community, which plays an important role in mediating the denitrifying process, was relatively diverse and positively influenced by soil available potassium and available phosphorus. 参考文献 相似文献 引证文献

Le renouvellement récent des faunes de vertébrés sur l’île de Cavallo (archipel des Lavezzi, Corse)

We present a recent survey of the vertebrate fauna of Cavallo, a small island belonging to the Lavezzi archipelago located between Corsica and Sardinia. This island is the only inhabited one off the coast of Corsica and underwent deep landscape and ecosystem changes in the past 50 years induced by touristic development. The herpetofauna of the Cavallo island has changed with two recent colonisations, one green frog and one gecko. Two amphibian species and four reptiles live nowadays on this island. Concerning the breeding landbirds, this island has been visited by ornithologists more or less regularly since 1955. Several species have colonized the island while others have left. These changes are due to important modifications of the habitats, such as urbanization, the decline of high matorral and grasslands, but also the development of gardens and the creation of a permanent wetland. Today, 13 species of landbirds breed on Cavallo. Several introduced mammal species recorded in the 1980s seem to have vanished, and today the list is restricted to the introduced Black rat and two or three bat species.

Biogenic processes or terrigenous inputs? Permanent water bodies of the Northern Ponds in the Lake MacLeod basin of Western Australia

The saline wetlands of the Northern Ponds, Lake MacLeod, contravene general classifications for salt lakes because, despite enduring high levels of evaporation, they contain permanently inundated ponds that are continually supplied with seawater by a seepage face from the Indian Ocean. The present study investigated the physical, sediment and chemical characteristics of these ponds, using sonar, flow-rate measurements, microscopy and inductively coupled plasma–mass spectrometry to understand the role of biogenic and terrigenous inputs on the benthic habitats. The chemical composition of the water bodies did not differ significantly from the seawater feedstock, which facilitates biogenic sediment accumulation. The largest permanent water body differs from the other ponds in physical and chemical structure, in that, possibly because of its size, it is dominated by terrigenous inputs, which result in higher nutrient concentrations and non-biogenic sediments. The Northern Ponds represent a system where the hydrology permits the establishment of permanent wetlands in an arid environment. Because of the constant supply of seawater, the ponds have a blend of habitat characteristics from marine and other inland salt-lake environments. The present study showed that a ‘marine-like’ state can override more typical characteristics of inland water bodies where discharge rates are high and water-residence times are low.

Comparison of Microbial Community Composition and Diversity in Native Coastal Wetlands and Wetlands that Have Undergone Long-Term Agricultural Reclamation

Land conversion from wetlands to farmlands is pervasive in coastal areas. However, comparisons of soil microbial community structure between native wetlands and long-term reclaimed farmlands have received less attention. We investigated this issue in two Phragmities austrialis wetlands with different hydrological regimes (permanent and seasonally inundated) based on phospholipid fatty acid (PLFA) analysis and 16S rRNA pyrosequencing. In the permanent wetland, the farmland had higher contents of fungal (+331 %), bacterial (+60 %), actinomycetic (+50 %), and total (+81 %) PLFAs compared with the native wetland. In the drained wetland, the farmland had higher fungal (+982 %) PLFAs contents, but lower contents of bacterial (−78 %), actinomycetic (−98 %) and total (−54 %) PLFAs compared with the native wetland. Bacteria and actinomycetes were dependent on wetland hydrological conditions, while fungi were sensitive to other alterations. Fungal/bacterial-PLFAs ratios were higher in farmlands than wetlands. The relative abundances of Proteobacteria, Firmicutes and Bacteroidetes were higher in farmlands than wetlands. Compared with PLFA, 16S rRNA differentiated fewer differences in bacterial community composition. Farmlands had lower bacterial Shannon-Wiener index compared with the permanent wetland, but not for the seasonal wetland. In conclusion, native wetlands and associated farmlands have differences in microbial community structure and diversity, which are mainly dependent on hydrological and nutrient conditions.

Monitoring dual-season hydrological dynamics of seasonally flooded wetlands in the lower reach of Mayurakshi River, Eastern India

The seasonally flooded wetlands are often neglected due to their ephemeral and erratic appearance and small size, however, their hydro-ecological importance, socio-economic values are equivalent to the permanent wetlands. Using dual-season Landsat multi-spectral imagery, this study highlights a comprehensive monitoring of the hydrological dynamics of wetlands in the lower reach of the Mayurakshi River at a 14-year temporal resolution with the seasonal mode of 1987–2014 time frames. Our results demonstrate the seasonal and periodic hydrological variability of water presence frequency (WPF) in six wetland complexes defined for this study. The Hijal, Ghambira and Maldah wetland complexes are highly affected by the change of WPF, while Dwarka complex is relatively stable. The assessment of WPF change analysis showed that the method is proficient in identifying stable and physically vulnerable wetland patches and absolute loss of wetland inundation frequency resulting from various anthropogenic causes like regulation of river, dry farming practices and other integrated developmental works. The outcome of our study provides a robust basis for the fundamental hydrological and ecological studies and helpful for the conservation and management of seasonally flooded wetland resources in the tropical monsoon climate.

Temperature and Hydrology Affect Methane Emissions from Prairie Pothole Wetlands

The Prairie Pothole Region (PPR) in central North America consists of millions of depressional wetlands that each have considerable potential to emit methane (CH4). Changes in temperature and hydrology in the PPR from climate change may affect methane fluxes from these wetlands. To assess the potential effects of changes in climate on methane emissions, we examined the relationships between flux rates and temperature or water depth using six years of bi-weekly flux measurements during the snow-free period from six temporarily ponded and six permanently ponded wetlands in North Dakota, USA. Methane flux rates were among the highest reported for freshwater wetlands, and had considerable spatial and temporal variation. Methane flux rates increased with increasing temperature and water depth, and were especially high when conditions were warmer and wetter than average (163 ± 28 mg CH4 m−2 h−1) compared to warmer and drier (37 ± 7 mg CH4 m−2 h−1). Methane emission rates from permanent wetlands were less sensitive to changes in temperature and water depth compared to temporary wetlands, likely due to higher sulfate concentrations in permanent wetlands. While the predicted increase in temperature with climate change will likely increase methane emission rates from PPR wetlands, drier conditions could moderate these increases.

Spatial and temporal variation of invertebrate community structure in flood-controlled tropical floodplain wetlands

ABSTRACTThe Phongolo floodplain in South Africa is a unique system because of its biodiversity and socio-economic value. The spatial and temporal changes of invertebrate communities of the downstream floodplain influenced by controlled flooding from an upstream dam are poorly understood. The study investigated the spatial and temporal changes in community assemblage of macroinvertebrates and zooplankton in the permanent wetlands (pans) of the Phongolo floodplain in relation to controlled flooding. This was achieved by sampling during the dry period (September) and after controlled release of water (December). Although controlled flooding did not coincide with significant changes in the taxon diversity of macroinvertebrates and zooplankton, macroinvertebrate regional taxa richness (γ-diversity) was relatively higher in the period coinciding with controlled flood (December) compared to the dry period. For zooplankton, regional taxa diversity was similar in both periods. The average local taxa richness (α-diversity) was higher after the controlled flooding period for both macroinvertebrates and zooplankton. Spatial species turnover (β-diversity) was lower after the controlled flooding period suggesting the homogenization of aquatic communities through flooding. The community pattern of macroinvertebrates, but not of zooplankton, significantly changed after the controlled flooding period. The most important local environmental variables determining the distribution of both macroinvertebrates and zooplankton were macrophyte cover and dissolved oxygen. As the invertebrate diversity in this unique floodplain is at least partly dependent on release of water from the dam, future management schemes aimed to meet irrigation demands for agriculture should always consider flooding of the precious floodplain wetlands to maintain ecosystem integrity.

Performance evaluation of OCO-2 XCO2 signatures in exploring casual relationship between CO2 emission and land cover

Continental scale monitoring is the primary satellite remote sensing method in previous studies for carbon emission patterns in relation to land cover. OCO-2 satellite is the most advanced CO2 monitoring satellite with high spatial resolution. This paper investigated performance of OCO-2 XCO2 signature in exploring causal relationship between land cover and carbon emissions. The land cover types (croplands, permanent wetlands, urban and built-up) influenced by development activities generally show higher XCO2 mean concentrations than non-anthropogenic land cover types. Evergreen broadleaf forest shows lowest local R2 while highest local R2 is generated from croplands. The adjusted R2s (the explanation power of geographically weighted regression, GWR model) were statistically significant on every land cover type. This research output could be used as a valuable reference that improved spatial resolution of OCO-2 could explain co-relationship between local CO2 flux and land cover for specific region within a country.

Identificación espacial de los sistemas de humedales continentales de Colombia

El Repositorio Institucional de Documentación Científica del Instituto Alexander von Humboldt tiene como propósito recopilar, almacenar, preservar y difundir la producción científica que genera el Instituto como resultado de sus investigaciones y en esa perspectiva busca retornar al país el conocimiento institucional sobre la biodiversidad colombiana.

Disease dynamics of red-spotted newts and their anuran prey in a montane pond community.

Long-term monitoring of amphibians is needed to clarify population-level effects of ranaviruses (Rv) and the fungal pathogen Batrachochytrium dendrobatidis (Bd). We investigated disease dynamics of co-occurring amphibian species and potential demographic consequences of Rv and Bd infections at a montane site in the Southern Appalachians, Georgia, USA. Our 3-yr study was unique in combining disease surveillance with intensive population monitoring at a site where both pathogens are present. We detected sub-clinical Bd infections in larval and adult red-spotted newts Notophthalmus viridescens viridescens, but found no effect of Bd on body condition of adult newts. Bd infections also occurred in larvae of 5 anuran species that bred in our fishless study pond, and we detected co-infections with Bd and Rv in adult newts and larval green frogs Lithobates clamitans. However, all mortality and clinical signs in adult newts and larval anurans were most consistent with ranaviral disease, including a die-off of larval wood frogs Lithobates sylvaticus in small fish ponds located near our main study pond. During 2 yr of drift fence monitoring, we documented high juvenile production in newts, green frogs and American bullfrogs L. catesbeianus, but saw no evidence of juvenile recruitment in wood frogs. Larvae of this susceptible species may have suffered high mortality in the presence of both Rv and predators. Our findings were generally consistent with results of Rv-exposure experiments and support the purported role of red-spotted newts, green frogs, and American bullfrogs as common reservoirs for Bd and/or Rv in permanent and semi-permanent wetlands.

Modelling water-table depth in a primary aquifer to identify potential wetland hydrogeomorphic settings on the northern Maputaland Coastal Plain, KwaZulu-Natal, South Africa

The primary aquifer on the Maputaland Coastal Plain in northern KwaZulu-Natal, South Africa, is the principal source of water for rivers, lakes and most of the wetlands in dry periods, and is recharged by these systems in wet periods. Modelling hydrologic conditions that control regional water-table depth can provide insight into the spatial patterns of wetland occurrence and of the persistence of wet conditions that control their character. This project used a groundwater model (MODFLOW) to simulate 10-year water-table fluctuations on the Maputaland Coastal Plain from January 2000 to December 2010, to contrast the conditions between wet and dry years. Remote sensing imagery was used to map “permanent” and “temporary” wetlands in dry and wet years to evaluate the effectiveness of identifying the suitable conditions for their formation using numerical modelling techniques. The results confirm that topography plays an important role on a sub-regional and local level to support wetland formation. The wetlands’ extent and distribution are directly associated with the spatial and temporal variations of the water table in relation to the topographical profile. Groundwater discharge zones in the lowland (1–50 masl) areas support more permanent wetlands with dominantly peat or high organic soil substrates, including swamp forest and most of the permanent open water areas. Most temporary wetlands associated with low-percentage clay occurrence are through-flow low-lying interdune systems characterised by regional fluctuation of the water table, while other temporary wetlands are perched or partially perched. The latter requires a more sophisticated saturated-unsaturated modelling approach.

Isolation, Characterization and Antimicrobial Activities of Actinomycetes Isolated from a Tunisian Saline Wetland

The “Sebkha of Monastir” is a Tunisian permanent wetland that constitutes a virgin environment to search new biotechnologically relevant microorganisms and activities. A total of 71 different strains were isolated, including 54 Streptomyces, 2 Micromonospora, 2 Nocardia, 4 Pseudonocardia and 9 non-streptomyces actinomyetes. Interesting antimicrobial activities were detected in liquid and solid cultures. The antimicrobial profiles depended upon the culture medium and/or the organic extraction. Several bioactive compounds were identified by liquid chromatography (LC) combined with mass spectrometry (MS) and then analyzed by MEDINA´s database and the Dictionary of Natural Products Chapman & Hall. Isoflavones (genistein and deidzein) are the most produced known active compounds. The chemical structures of four putative novel compounds were elucidated. Interestingly, unknown compounds produced by two strains (A8 and A11) actives against Gram negative bacteria were selected for further analysis on a large-scale. 16S rDNA sequencing allowed us to classify some active isolates as members of the Streptomyces and Micromonospora genera. All these findings prove the high antimicrobial activity of the actinomycetes strains isolated from the “Sebkha of Monastir”. The potential of this and other relatively unexplored extreme environments constitute a source of new biologically active secondary metabolites.

Lesser Adjutant Leptoptilos javanicus Horsfield, 1821 (Ciconiiformes: Ciconiidae) in the dry lowlands of Sri Lanka: distribution, ecology, and threats

&lt;p&gt;The&lt;strong&gt; &lt;/strong&gt;Lesser Adjutant &lt;em&gt;Leptoptilos javanicus&lt;/em&gt; is a globally threatened species of stork; in Sri Lanka, it is a scarce resident breeder, and the largest bird in the country, yet the population status and ecology of the species is poorly understood. This study tracks the stork’s spatial distribution and habitat use within the island, along with aspects of its ecology. Data was collected via field sampling and questionnaire surveys, over a period of five years across the lowlands of the country. The bird was observed 184 times, with numbers per sighting ranging from 1–17 individuals. The species’ distribution was restricted to dry lowlands (rainfall &amp;lt;2200mm, elevation &amp;lt;300m). The bird showed preference for savannah/woody savannahs, dry mixed evergreen forests, permanent wetlands, and croplands, and was prominently found within protected areas. Lesser Adjutants were generally solitary, except in the driest months of the year (i.e., August–September and March–April), which are probably the two breeding periods of the bird in Sri Lanka. Except for an abandoned nest, no active nest was found. Habitat loss and fragmentation, hunting pressure, agricultural intensification, and development projects were identified as potential threats faced by the species, which varied in magnitude across the country.&lt;/p&gt;&lt;div&gt; &lt;/div&gt;

Reactivity and speciation of mineral-associated arsenic in seasonal and permanent wetlands of the Mekong Delta

Millions of people in the deltaic regions of S/SE Asia regularly consume As contaminated groundwater. Arsenic persists within these groundwaters despite being flushed by several pore volumes of recharge, indicative of an in situ solid phase source. Despite the importance of this solid phase source, the identity and reactivity of the minerals hosting and releasing As in the deltaic aquifers remain poorly constrained. Here we seek to define the chemistry and reactivity of As and its host minerals in aquifer sediments recharged by both seasonally saturated and permanent wetlands in the Mekong Delta of Cambodia.Sediment cores were retrieved to depths of up to 30m. Selective extractions on near-surface sediments (to depths of 4–6m) indicate that more than a third (27–50%) of the Fe in the profile is “reducible” (citrate–bicarbonate–dithionite–extractable) – nominally consisting of Fe(III) oxides. The Fe(III) oxide fraction was approximately the same under seasonal wetlands (mean=39%) compared with sediments from beneath permanent wetlands (mean=37%). Correspondingly, Fe K-edge extended X-ray absorption fine structure (EXAFS) spectra analysis indicates that the Fe mineral phases are predominantly goethite and hematite (30–50%).Analysis of solid phase As speciation by X-ray absorption near edge structure (XANES) spectroscopy showed arsenate in the shallowest sediments (upper 1 and 4m of seasonal and permanent wetlands), and arsenite and/or As sulfides as the dominant phases in the deeper sediments. The reducible As fraction ranged from 17% to 42% of the total As at both sites. The exception was found in a peat layer at 6m beneath the seasonal wetland, in which only 1% of the total As was reducible. Arsenian pyrite was the predominant form of As in the peat. Thus, a pool of As hosted by reducible mineral phases persists in sediments below both the seasonal and permanently saturated wetland sites.

Projecting the Hydrologic Impacts of Climate Change on Montane Wetlands.

Wetlands are globally important ecosystems that provide critical services for natural communities and human society. Montane wetland ecosystems are expected to be among the most sensitive to changing climate, as their persistence depends on factors directly influenced by climate (e.g. precipitation, snowpack, evaporation). Despite their importance and climate sensitivity, wetlands tend to be understudied due to a lack of tools and data relative to what is available for other ecosystem types. Here, we develop and demonstrate a new method for projecting climate-induced hydrologic changes in montane wetlands. Using observed wetland water levels and soil moisture simulated by the physically based Variable Infiltration Capacity (VIC) hydrologic model, we developed site-specific regression models relating soil moisture to observed wetland water levels to simulate the hydrologic behavior of four types of montane wetlands (ephemeral, intermediate, perennial, permanent wetlands) in the U. S. Pacific Northwest. The hybrid models captured observed wetland dynamics in many cases, though were less robust in others. We then used these models to a) hindcast historical wetland behavior in response to observed climate variability (1916–2010 or later) and classify wetland types, and b) project the impacts of climate change on montane wetlands using global climate model scenarios for the 2040s and 2080s (A1B emissions scenario). These future projections show that climate-induced changes to key driving variables (reduced snowpack, higher evapotranspiration, extended summer drought) will result in earlier and faster drawdown in Pacific Northwest montane wetlands, leading to systematic reductions in water levels, shortened wetland hydroperiods, and increased probability of drying. Intermediate hydroperiod wetlands are projected to experience the greatest changes. For the 2080s scenario, widespread conversion of intermediate wetlands to fast-drying ephemeral wetlands will likely reduce wetland habitat availability for many species.

Spatial occupancy models for predicting metapopulation dynamics and viability following reintroduction

SummaryThe reintroduction of a species into its historic range is a critical component of conservation programmes designed to restore extirpated metapopulations. However, many reintroduction efforts fail, and the lack of rigorous monitoring programmes and statistical models have prevented a general understanding of the factors affecting metapopulation viability following reintroduction.Spatially explicit metapopulation theory provides the basis for understanding the dynamics of fragmented populations linked by dispersal, but the theory has rarely been used to guide reintroduction programmes because most spatial metapopulation models require presence–absence data from every site in the network, and they do not allow for observation error such as imperfect detection.We develop a spatial occupancy model that relaxes these restrictive assumptions and allows for inference about metapopulation extinction risk and connectivity. We demonstrate the utility of the model using six years of data on the Chiricahua leopard frogLithobates chiricahuensis, a threatened desert‐breeding amphibian that was reintroduced to a network of sites in Arizona USA in 2003.Our results indicate that the model can generate precise predictions of extinction risk and produce connectivity maps that can guide conservation efforts following reintroduction. In the case ofL. chiricahuensis, many sites were functionally isolated, and 82% of sites were characterized by intermittent water availability and high local extinction probabilities (0·84, 95% CI: 0·64–0·99). However, under the current hydrological conditions and spatial arrangement of sites, the risk of metapopulation extinction is estimated to be &lt;3% over a 50‐year time horizon.Low metapopulation extinction risk appears to result from the high dispersal capability of the species, the high density of sites in the region and the existence of predator‐free permanent wetlands with low local extinction probabilities. Should management be required, extinction risk can be reduced by either increasing the hydroperiod of existing sites or by creating new sites to increase connectivity.Synthesis and applications. This work demonstrates how spatio‐temporal statistical models based on ecological theory can be applied to forecast the outcomes of conservation actions such as reintroduction. Our spatial occupancy model should be particularly useful when management agencies lack the funds to collect intensive individual‐level data.

Land use and wetland drainage affect water levels and dynamics of remaining wetlands

Depressional wetlands are productive and unique ecosystems found around the world. Their value is due, in part, to their dynamic nature, in which water levels fluctuate in response to climate, occasionally drying out. However, many wetlands have been altered by consolidation drainage, where multiple, smaller wetlands are drained into fewer, larger, wetlands causing higher water levels. We evaluated whether current (2003–2010) water surface areas were greater than historical (1937–1969) water surface areas of 141 randomly selected semipermanent and permanent wetlands across the Prairie Pothole Region of North Dakota, USA. We also evaluated whether differences between historical and current hydrology of these wetlands were attributable to consolidation drainage. For each of these wetlands, we digitized water surface areas from aerial photography during historical and current eras. Our results indicated that water surface areas are currently 86% greater in sample wetlands than they were historically and that differences can be attributed to consolidation drainage. Water surface areas of consolidated wetlands in extensively drained landscapes were 197% greater than those with no drainage and now require more extreme drought conditions to dry out. Wetlands in extensively drained catchments were larger, dry out less frequently, and have more surface‐water connections to other wetlands via ditches. These factors make conditions more favorable for the presence of fish that decrease abundances of aquatic invertebrates and reduce the productivity and quality of these wetlands for many species. Our results support the idea that intact wetlands serve an important role in water storage and groundwater recharge and reduce down‐stream runoff.

Development of a decision support tool: preliminary analysis to improve field data collection in Kathiraveli Village, Sri Lanka

This paper focuses specifically on the development of a water balance model that will support agricultural decision making for the irrigation field and water supply tanks. The study based on an irrigation system within Kathiraveli, an isolated war affected village in north-eastern Sri Lanka. The irrigation system is used to deliver water to approximately 100 farmers. Estimates or measurements of water availability at the start of the cultivation period are able to be combined with estimates of likely future inflows based on previous rainfall to determine optimum crop selection and crop area allocation. The model consists of three modules: a crop water requirement calculator, a water tank balance model, and a model which simulates the storage in the permanent wetland attached to the irrigation tank. Due to limited budgets and timeframes to obtain input data, a careful balance between accuracy, complexity and cost needed to be reached to ensure that the model can be accurate for its intended use. To do this the model was ran initially under baseline conditions. A sensitivity analysis was then performed to assess the importance of major variables; the outcomes of this study was used to prioritise the collection of field data.

Flora vascular de humedales permanentes y transitorios bonaerenses (Buenos Aires, Argentina)

Fil: Passarelli, Lilian. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Estudios de Anatomia Vegetal Evolutiva y Sistematica; Argentina