Wetland Basins Research Articles

Agronomic and economic effects of wetlands on crop yields using precision agriculture data

CONTEXTWetland drainage has become an increasingly important conservation issue in the Prairie Pothole region of North America. Financial incentives for annual crop production have driven wetland drainage for decades, and the removal of wetlands has detrimentally impacted key wetland ecosystem services such as wildlife habitat and carbon sequestration. Past studies which model the farmer's decision to drain wetlands often operate on the assumption that drained wetlands will produce similar yields to upland regions of the field. OBJECTIVEOur objective is to estimate the effects of wetlands and their buffer zones on crop yields, farm financial performance, and incentives for wetland drainage in the Prairie Pothole Region. METHODSWe combine precision yield data and detailed wetland mapping data from 36 fields in the Black and Dark Brown soil zones of Saskatchewan, Canada to estimate the agronomic impacts of wetlands and their buffer areas on crop yields. Then, we incorporate these yield effects into a farm accounting model with three wetland drainage scenarios to estimate the annual per cultivated acre net benefits of wetland drainage in the study area, and compare these results to those estimated without wetland yield effects. RESULTSWe find that yields in wetland basins are relatively lower than the field's average yield, with substantial variability with respect to crop type, soil zone, and annual precipitation. Wetland drainage can mitigate these yield effects, but yields in drained wetland basins still fail to meet the field average yield. These yield effects can extend more than 50 m beyond the wetland boundary. We find that these effects substantially impact the net benefits of wetland drainage. The returns from wetland drainage increase when yield effects are considered. On average, full wetland drainage within the study area increases net benefits by $17 to $33 per cultivated acre relative to full wetland restoration. SIGNIFICANCEThe results demonstrate the importance of considering wetland and buffer zone yield effects in wetland drainage decisions, improve our understanding of wetland costs, and potentially inform policy development and the design of incentives for wetland conservation in agricultural landscapes.

Future amazon basin wetland hydrology under projected climate change

Climate change over the Amazon basin has the potential to cause major hydrological and ecological impacts over the region’s extensive wetlands. To investigate this the Joint UK Land Environment Simulator (JULES) land surface model is first extended to include riverine inundation. Potential impacts of future climate change on Amazon basin wetlands are then evaluated by driving this updated JULES model with modelled meteorology projections from six different climate simulations reaching approximately 4°C global warming at the end of the 21st Century. The projected changes in inundation extent and seasonality are assessed over four major wetland regions. The simulations project, on average, a significant decrease in total Amazon basin inundated area of 11% (range: -36% to +9%) by the 2090s. This considerable spread is primarily driven by disparity in simulated precipitation changes, ultimately driven by sea surface temperature differences. The wetter contemporary climate simulations simulate the greatest drying by the end of this Century, resulting in the largest wetland area reductions. The largest qualitative disagreement is over the western Iquitos wetland, with inundated area changes ranging from a very large reduction of -53% to an increase of 12%. A new wetland classification scheme is developed to summarise the projected changes in wetland seasonality. The largest drops in simulated wetland season length occur over the Central/East Manaus and West Iquitos wetland regions, with reductions of up to 10 and 8 months respectively. Such significant changes in future inundation are likely to have a major impact on regional wetland hydrology and their ecosystems.

Wetland hydrological change and recovery across three decades of shifting groundwater management

Groundwater extraction compromises the function of groundwater-dependent ecosystems, such as freshwater wetlands. Identifying whether groundwater conservation restores wetland hydrology is a first step toward rehabilitating impaired wetlands. In the Tampa Bay region of Florida (U.S.), groundwater extraction rates have been declining since 1998, partly in response to desiccation of wetlands and waterbodies. This study uses monthly water-level data from 152 depressional wetlands over 28 years (1991–2018) to identify trends in wetland inundation, determine whether those trends vary among wetlands historically exposed to different rates of groundwater extraction, and describe relationships between the timing and extent of cutbacks in groundwater extraction and the timing and extent of changes in wetland inundation. Many wetlands (57 %) exhibited increased inundation in response to cutbacks in groundwater extraction, indicating that water conservation measures are inducing recovery. Further, increased inundation began in most wetlands immediately upon, or within two years of, the time extraction cutbacks occurred, although some recovering wetlands exhibited longer lags. An additional 26 % of wetlands had steady-state water levels with inundation similar to that of reference wetlands, potentially revealing a population of wetlands hydrologically unimpaired by nearby groundwater extraction. Another subset of wetlands (14 %) with steady-state water depths exhibited increasing deviations from basin-full water levels, suggesting subsidence of the wetland basin. Active intervention beyond cutbacks in groundwater extraction may be necessary to restore this subset, whereas passive restoration (reducing extraction) appears adequate for the majority of impacted wetlands. Rising water levels may amplify surface-water connections among wetlands, with ecological and biogeochemical consequences both for individual wetlands and for the whole wetlandscape. As a host of human activities continue to rely on groundwater extraction, this study demonstrates the potential for, as well as variability in, hydrological recovery across a wetland-rich, low-relief landscape following the enactment of water conservation policies.

Diversity and distribution of birds in a Congo Basin wetland: the upstream part of the Nyong River valley in Cameroon along two regions (Centre and East)

Several studies have recently been carried out on the avifauna of Cameroon and have made it possible to update the data for certain regions; however, no recent study has been carried out on the upper valley of the Nyong River, which is a wetland, and therefore the data remains quite old. We carried out a study on the avifauna of this valley and birds were sampled over a period of one year using the mist-netting method. The collected data were analyzed using PAST bio statistical software for the diversity and distribution of the avifauna. A total of 268 individuals belonging to 69 bird species were captured, with a high proportion of passerines (73%) compared with non-passerines. The high diversity of the avifauna is supported by estimated values of diversity indexes which show an absence of supremacy of one species (H’=3.64) and an equal distribution of individuals in their environment (J’=0.86). With the value of the Simpson diversity index of 0.96, our result confirms high diversity within the upper valley of the Nyong River avifauna but it also reveals the abundance of this avifauna. In addition, the Kruskal-Wallis test value of 0.04 showed a significant difference in the distribution of relative abundances of taxa at the areas investigated and that different could be justified by a difference in the physiognomy of their vegetation. This study confirms that the composition as well as the structure of the upper valley of the Nyong River as observed in the field play a main role in the diversity of bird species due to the presence of feeding, resting and nesting areas. Based on our distribution and diversity analysis, the pattern of variation in distribution of birds in this wetland appears to lean on environmental factors and particularly the vegetation, which played the main role with a mixture of poor and good dispersers, migratory and vagrant due to presence of lush vegetation all year round.

Urban Stormwater Phosphorus Export Control: Comparing Traditional and Low-impact Development Best Management Practices.

Data from the International Stormwater Best Management Practices (BMP) Database were used to compare the phosphorus (P) control performance of six categories of stormwater BMPs representing traditional systems (stormwater pond, wetland basin, and detention basin) and low-impact development (LID) systems (bioretention cell, grass swale, and grass strip). Machine learning (ML) models were trained to predict the reduction or enrichment factors of surface runoff concentrations and loadings of total P (TP) and soluble reactive P (SRP) for the different categories of BMP systems. Relative to traditional BMPs, LIDs generally enriched TP and SRP concentrations in stormwater surface outflow and yielded poorer P runoff load control. The SRP concentration reduction and enrichment factors of LIDs also tended to be more sensitive to variations in climate and watershed characteristics. That is, LIDs were more likely to enrich surface runoff SRP concentrations in drier climates, when inflow SRP concentrations were low, and for watersheds exhibiting high impervious land cover. Overall, our results imply that stormwater BMPs do not universally attenuate urban P export and that preferentially implementing LIDs over traditional BMPs may increase TP and SRP export to receiving freshwater bodies, hence magnifying eutrophication risks.

Riding the wetland wave: Can ducks locate macroinvertebrate resources across the breeding season?

Food availability varies considerably over space and time in wetland systems, and consumers must be able to track those changes during energetically-demanding points in the life cycle like breeding. Resource tracking has been studied frequently among herbivores, but receives less attention among consumers of macroinvertebrates. We evaluated the change in resource availability across habitat types and time and the simultaneous density of waterfowl consumers throughout their breeding season in a high-elevation, flood-irrigated system. We also assessed whether the macroinvertebrate resource density better predicted waterfowl density across habitats, compared to consistency (i.e., temporal evenness) of the invertebrate resource or taxonomic richness. Resource density varied marginally across wetland types but was highest in basin wetlands (i.e., ponds) and peaked early in the breeding season, whereas it remained relatively low and stable in other wetland habitats. Breeding duck density was positively related to resource density, more so than temporal resource stability, for all species. Resource density was negatively related to duckling density, however. These results have the potential to not only elucidate mechanisms of habitat selection among breeding ducks in flood-irrigated landscapes but also suggest there is not a consequential trade-off to selecting wetland sites based on energy density versus temporal resource stability and that good-quality wetland sites provide both.

Climate change effects on animal presence in the Massaciuccoli Lake basin

Big-data mining approaches based on Artificial Intelligence models can help forecast biodiversity changes before they happen. These approaches can predict macroscopic species distribution patterns and trends that can inform preventive measures to avoid the loss of ecosystem functions and services. They can, therefore, help study and mitigate climate change implications on biodiversity conservation in fragile ecosystems. Wetlands are particularly fragile ecosystems where climate change poses severe risks and has dramatically reduced their size over the past century, with profound consequences on biodiversity and ecosystem services. Through big-data mining approaches, we can predict future wetland biodiversity trends in the context of climate change. This paper proposes such predictive analysis for a specific wetland: The Massaciuccoli Lake basin in Tuscany, Italy. This basin is a critical tourist attraction due to its rich biodiversity, making it an area of interest for citizens, tourists, and scientists. However, the region's suitability for native and non-native species is at risk due to climate and land-use change. Using machine-learning models, we predict the potential effects of climate change on animal spatial distribution in the basin under different greenhouse gas emission scenarios. The results suggest that habitat suitability has generally improved from 1950 to today, presumably owing to the targeted conservation strategies adopted in the area, but climate change will severely reduce bird biodiversity by 2050 while favouring several insect species' proliferation and other species' habitat change, even under a medium-emission scenario. This will lead to significant changes in the basin's biodiversity. Our methodology is adaptable to other wetland basins, being fully based on open data and models. The spatially explicit modelling used in this research provides valuable information for policymakers and spatial planners, complementing traditional biodiversity trend analyses.

Pengolahan Limbah Cair Rumah Makan Dengan Constructed Wetlands Skala Rumah Tangga

Wastewater from restaurants has a high organic content. Wastewater must be processed until it conforms with the effluent standard before being disposed of in water. Construction of subsurface wetland is one of the treatment options. This study made use of a reactor that Kiambang and Melati Air had planted. Sedimentation basin, wetland basin, and treatment basin are the three reservoirs used in this study. The wastewater was a sedimented effluent from restaurant operations. Seeding, acclimation, and running are the processes used. running for seven days. The variables under test were pH, TSS, and BOD (biological oxygen demand). Before treatment, the concentration is BOD 546,75 mg/l, TSS 340 mg/l, and pH 7,24. After treatment, the concentration is BOD 30,75 mg/l, TSS 95 mg/l, and pH 7,42. As a result, BOD has an efficiency of 94,376% and TSS has an efficiency of 72%. The concentrations of TSS did not meet the set quality criteria, although the levels of BOD and pH did.

Asymmetric impacts of natural and anthropogenic factors on wetland landscape evolution in Fenhe River Basin, China

In recent years, Fenhe River Basin (FRB) wetlands have been facing severe challenges due to climate change and human activities. It was of great significance to understand the dynamic changes of FRB wetlands and their driving factors for ecological protection. Based on the land use data, runoff, rainfall and GDP data of FRB from 1980 to 2020, the evolution characteristics and driving factors of wetland pattern in FRB were analyzed. The results showed that the wetland types in FRB mainly included paddy, reservoir, river, beach and marsh. Among them, natural wetlands accounted for 72.46 %, and constructed wetlands accounted for 27.53 %. The main types of wetlands in FRB were river, reservoirs and beach, which account for 92.26 % of the whole wetland area. However, the dominant position of reservoir patch was more obvious than the others during 1980–2020. Landscape index showed that the shape of landscape tended to be regular and became more fragmentation. The transfer between wetlands and other land use types mainly occurred in the northern and southern parts of the FRB, and the main conversion types were occurred between dry land and wetlands, grassland and wetlands. Both natural and human factors drove the evolution pattern of wetlands, but the emphases were different. Runoff had a significant effect on wetland pattern at landscape level, while rainfall had a more significant effect on wetland evolution at class level. Urbanization rate and GDP had important effects on the evolution of wetland pattern at both class and landscape levels.

A FOSSIL FOREST FROM ITALY REVEALS THAT WETLAND CONIFERS THRIVED IN EARLY PERMIAN PERI-TETHYAN PANGEA

AbstractIn-situ fossil forests are valuable biogenic archives for the structure and setting of paleocommunities and the ecology of their organisms. Here, we present the first trees preserved in growth position in their embedding strata from the Kungurian (lower Permian) Athesian Volcanic Group, Northern Italy—one of the most extensive volcanic successions of post-Variscan Euramerica. We reconstruct the structure, rise and demise, and paleoecology of the forest based on high-resolution documentation of facies architectures and petrography, and the paleontological and taphonomic characters of the fossil content. Generally, the fossiliferous strata record a volcanotectonically controlled base-level rise in a limnic, possibly endorheic wetland basin from a low-relief volcanic landscape. The forest, preserved as calcified stem bases with roots, grew during a short interval of lake-level stasis on a small deltaic sheetflood fan. The forest comprised trees less than 5 m tall with tabular root systems adapted to the waterlogged substrate, and was buried and destroyed by mass flows following rapid submergence. These mass-flow deposits yield parautochthonous woody debris providing anatomical evidence of conifers as the major arborescent plants of the fossil forest. Our results not only elucidate the root architecture of Paleozoic conifers, but also document the ecomorphological plasticity of these plants and substantiate the presence of coniferopsids in wetlands around the Carboniferous/Permian boundary. Further, the evidence of lake perenniality in the studied succession is among the youngest known from the Permian of Europe, pointing to the highly differentiated late-icehouse impacts on continental environments in the Euramerican tropics.

Evaluation of impacts of climate change on natural and managed wetland basins

AbstractLow floodplain wetlands such as the Western Everglades in South Florida are vulnerable to extreme weather events, and their water quality and ecosystem functions vary greatly depending on changes in water levels and discharges. The future (i.e., the mid and late 21st century) climate is projected to result in increased frequency and magnitude of extreme events, which could negatively affect the hydroecological function of the wetlands. Wetland management practices have commonly been implemented to protect wetlands and their functions, but it is not clear whether the current management practices can still be effective in projected climate change scenarios. The main goal of this study was to evaluate the impacts of climate change on the runoff and total phosphorus (TP) of natural (L28 Gap) and managed (L28) wetland watersheds in the Western Everglades. For the assessment, we employed future climate projections made using 29 general circulation models (GCMs) and the Watershed Assessment Model (WAM), a watershed loading model. The WAM was calibrated and validated for the baseline period (2000–2014), and the bias‐corrected climate projections were incorporated into the model to project the runoff discharge and TP loads for the near‐future (2030–2044) and far‐future (2070–2084) periods in two carbon emission scenarios. The modeling results show that the natural wetland watershed would be more vulnerable to projected climate change than the managed wetland watershed. The impact of projected climate change scenarios on daily runoff and TP loads was modulated by water control facilities and practices in the managed watershed, highlighting the significance of watershed management practices for improved water quality under projected climate change. This study demonstrates how the local natural and managed wetland watersheds distinctly respond to the global‐scale changes and emphasizes the role of water management practices in wetland basins, which are expected to help develop effective climate change adaptation plans for improved sustainability of wetland systems.

Spatio-temporal changes of evapotranspiration over the Zoige Wetland Basin in China using TSEB and GF satellites

ABSTRACT The Zoige wetland located in the eastern margin of the Tibet Plateau, is very important for the runoff regulation and biodiversity in the Yellow River basin. Due to the large non-uniformity of the alpine wetland surface, the use of higher spatial resolution satellite remote sensing data is essential to match or validate the results of ground observation. The land evapotranspiration in this survey was estimated by using the GF-4 satellite data from 2016 to 2020 into the Two Source Energy Balance (TSEB) model, and the estimated evapotranspiration is compared to the ground observation. The results show that: (1) the regression analysis of the actual observed evapotranspiration and the evapotranspiration estimated by the TSEB model shows that the actual evapotranspiration and the evapotranspiration calculated by the TSEB model have a good positive linear correlation (R2 > 0.8) at the Maqu observation site and the Huahu wetland observation site. Therefore, the accuracy of the evapotranspiration calculated by the TSEB model is high. (2) The spatio-temporal distribution of evapotranspiration and relevant land surface variables is generally characterized by high in the southeast and low in the northwest over the Zoige wetland basin. (3) The mean daily evapotranspiration for different GF-4 observation over the Zoige area is as follows: 1.8 mm on 8 April 2018, 3.6 mm on 20 July 2016, 1.4 mm on 29 November 2020 and 0.9 mm on 15 December 2017, and the magnitudes of evapotranspiration of the different surface are as follows: waterbody > grassland > bare land. (4) The histogram of the frequency distribution of evapotranspiration show that 3.2–4.0 mm on 20 July 2016, 0–0.8 mm on 15 December 2017, 0.8–1.6 mm on 8 April 2018 and 1.6–2.4 mm on 29 November 2020 are the maximum evapotranspiration range over the Zoige wetlands area.

Data integration reveals dynamic and systematic patterns of breeding habitat use by a threatened shorebird

Incorporating species distributions into conservation planning has traditionally involved long-term representations of habitat use where temporal variation is averaged to reveal habitats that are most suitable across time. Advances in remote sensing and analytical tools have allowed for the integration of dynamic processes into species distribution modeling. Our objective was to develop a spatiotemporal model of breeding habitat use for a federally threatened shorebird (piping plover, Charadrius melodus). Piping plovers are an ideal candidate species for dynamic habitat models because they depend on habitat created and maintained by variable hydrological processes and disturbance. We integrated a 20-year (2000–2019) nesting dataset with volunteer-collected sightings (eBird) using point process modeling. Our analysis incorporated spatiotemporal autocorrelation, differential observation processes within data streams, and dynamic environmental covariates. We evaluated the transferability of this model in space and time and the contribution of the eBird dataset. eBird data provided more complete spatial coverage in our study system than nest monitoring data. Patterns of observed breeding density depended on both dynamic (e.g., surface water levels) and long-term (e.g., proximity to permanent wetland basins) environmental processes. Our study provides a framework for quantifying dynamic spatiotemporal patterns of breeding density. This assessment can be iteratively updated with additional data to improve conservation and management efforts, because reducing temporal variability to average patterns of use may cause a loss in precision for such actions.

Modelling impacts of climate change and anthropogenic activities on inflows and sediment loads of wetlands: case study of the Anzali wetland

Understanding the effects of climate change and anthropogenic activities on the hydrogeomorpholgical parameters in wetlands ecosystems is vital for designing effective environmental protection and control protocols for these natural capitals. This study develops methodological approach to model the streamflow and sediment inputs to wetlands under the combined effects of climate and land use / land cover (LULC) changes using the Soil and Water Assessment Tool (SWAT). The precipitation and temperature data from General Circulation Models (GCMs) for different Shared Socio-economic Pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, and SSP5-8.5) are downscaled and bias-corrected with Euclidean distance method and quantile delta mapping (QDM) for the case of the Anzali wetland watershed (AWW) in Iran. The Land Change Modeler (LCM) is adopted to project the future LULC at the AWW. The results indicate that the precipitation and air temperature across the AWW will decrease and increase, respectively, under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. Streamflow and sediment loads will reduce under the sole influence of SSP2-4.5 and SSP5-8.5 climate scenarios. An increase in sediment load and inflow was observed under the combined effects of climate and LULC changes, this is mainly due to the projected increased deforestation and urbanization across the AWW. The findings suggest that the densely vegetated regions, mainly located in the zones with steep slope, significantly prevents large sediment load and high streamflow input to the AWW. Under the combined effects of the climate and LULC changes, by 2100, the projected total sediment input to the wetland will reach 22.66, 20.83, and 19.93 million tons under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. The results highlight that without any robust environmental interventions, the large sediment inputs will significantly degrade the Anzali wetland ecosystem and partly-fill the wetland basin, resulting in resigning the wetland from the Montreux record list and the Ramsar Convention on Wetlands of International Importance.

Evidence of Woodland Management at the Eneolithic Pile Dwellings (3700–2400 BCE) in the Ljubljansko Barje, Slovenia?

It is assumed that people practiced woodland management, i.e., coppicing and pollarding, in prehistory, but details are poorly known. This study aims for a better understanding of woodland exploitation through time in the wetland basin of the Ljubljansko barje, Slovenia, from 3700-2400 BCE (Before Common Era). To do so, uncarbonized, waterlogged wood from 16 Eneolithic pile dwellings situated in two geographical clusters that cover a time span of c. 1300 years were subjected to age/diameter analysis. It is the first time that age/diameter analysis has been applied to multiple sites from the same region. The investigated posts represent a wide range of taxa, but oak (Quercus sp.) and ash (Fraxinus sp.) represent 75% of the total, indicating selective use of wood for this purpose. Diameter selection of ash may have taken place as well. At both site clusters, the age/diameter data do not reveal any unequivocal evidence for woodland management. Only at the youngest sites do the data possibly show some gradually changing practices. The outcomes are discussed within the framework of recent discussions about woodland management in Europe.

Estimation of soil loss due to erosion in the Tecocomulco wetland basin, Mexico

The basin of the Tecocomulco lagoon is in the southwest of the state of Hidalgo, encompassing part of the states of Puebla andTlaxcala. It was designated a RAMSAR site in 2003 by the Convention on Wetlands of International Importance. The waterresource of the Tecocomulco wetland is compromised by social and ecological uses and the real loss of the storage volume of thelagoon due to deforestation, causing an increase in soil erosion in the upper part of the basin, causing flooding, low yields inagricultural and livestock production, degradation of plant cover and loss of biodiversity. The objective was estimating the level oferosion in the Tecocomulco wetland, to justify the criteria to categorize it as a priority area for restoration and conservation. Theevaluation of the degree of hydric erosion was carried out based on the methodology proposed by Figueroa (1991), which uses theUniversal Soil Loss Equation (USLE), to estimate and predict average annual soil losses. To obtain statistics by erosion rangeaccording to the FAO (1984), the resulting map was classified into three ranges and subsequently statistical zoning was carried outto obtain the values. The results showed that 1,075,167.31 tons of soil loss per year were obtained, the most representative range orclass of erosion on the surface corresponds to "no or slight Erosion" that occupies 39.22% of the total surface of the basin

Lateglacial and Early Holocene palaeoenvironmental change and human activity at Killerby Quarry, North Yorkshire, UK

ABSTRACTThe hunter‐gatherers that entered the British peninsula after ice‐retreat were exploiting a dynamic, rapidly changing environment. Records of vegetation change and human occupation during the Lateglacial to Early Holocene in northern Britain are more commonly found at upland and cave sites. However, recent research highlights many areas of the Swale–Ure Washlands that preserve extensive environmental sequences in low‐lying ice‐wastage basins, channels and depressions. The Lateglacial–Early Holocene environment of Killerby Quarry, North Yorkshire, is investigated here using a multi‐proxy approach of sedimentary ancient DNA (sedaDNA), pollen, sedimentological (geochemistry and portable optically stimulated luminescence), and rare and well‐preserved archaeology (Lavvu structures and lithics). Results show that the wetland basins and kettleholes were small lakes or ponds in the Lateglacial surrounded by sedge‐fen and birch woodland. A gradual (centennial scale) succession to reed‐swamp and then marsh is seen by the Early Holocene. This environment formed the resource‐scape for hunter‐gatherer transitory settlement in both the Lateglacial (Late Upper Palaeolithic) and Holocene (Early Mesolithic), attracted by the rich communities of pond‐related flora and fauna as well as easy strategic landscape access by way of the River Swale, an arterial route through the landscape connecting the North Sea Basin with the Pennine uplands via the palaeolakes around Killerby.

Geomatics Applications in the Study of Geo-Environmental Changes in Alzaytun Basin Wetlands, the Middle of Siwa Depression

Geomatics Applications in the Study of Geo-Environmental Changes in Alzaytun Basin Wetlands, the Middle of Siwa Depression

Climate and Land Use Driven Ecosystem Homogenization in the Prairie Pothole Region

The homogenization of freshwater ecosystems and their biological communities has emerged as a prevalent and concerning phenomenon because of the loss of ecosystem multifunctionality. The millions of prairie-pothole wetlands scattered across the Prairie Pothole Region (hereafter PPR) provide critical ecosystem functions at local, regional, and continental scales. However, an estimated loss of 50% of historical wetlands and the widespread conversion of grasslands to cropland make the PPR a heavily modified landscape. Therefore, it is essential to understand the current and potential future stressors affecting prairie-pothole wetland ecosystems in order to conserve and restore their functions. Here, we describe a conceptual model that illustrates how (a) historical wetland losses, (b) anthropogenic landscape modifications, and (c) climate change interact and have altered the variability among remaining depressional wetland ecosystems (i.e., ecosystem homogenization) in the PPR. We reviewed the existing literature to provide examples of wetland ecosystem homogenization, provide implications for wetland management, and identify informational gaps that require further study. We found evidence for spatial, hydrological, chemical, and biological homogenization of prairie-pothole wetlands. Our findings indicate that the maintenance of wetland ecosystem multifunctionality is dependent on the preservation and restoration of heterogenous wetland complexes, especially the restoration of small wetland basins.

Invasiveness risk assessment of non-native species of the redbelly tilapia (Coptodon zillii, Gervais 1848) in Shadegan wetland basin

سابقه و هدف: ورود گونه­­ های ماهی مهاجم دراکوسیستم ­های آبی، سبب بروز انواع اثرات منفی اکولوژیکی و اقتصادی-اجتماعی می ­­شود. اولین گام در تجزیه و تحلیل مخاطرات ناشی از گونه­ های غیر­بومی، شناسایی خطر است و بر این اساس ابزارهای متعددی برای شناسایی و ارزیابی خطرات تهاجمی گونه­­ های غیربومی به منظور پشتیبانی تصمیم گیرندگان در تجزیه و تحلیل خطر تهاجمی این گونه ­­ها ایجاد شده است. هدف این پژوهش ارزیابی قدرت تهاجمی گونه غیربومی تیلاپیای شکم قرمز (Coptodon zillii) در حوضه آبریز تالاب شادگان (حوضه‌های آبریز کارون بزرگ و جراحی) با استفاده از برخی از این ابزارها می ­باشد.مواد و روش‌ها: میزان ریسک گونه در پروتکل ارزیابی ریسک سه ملیتی، بر اساس نتایج حاصل از دو بخش «احتمال استقرار» و «پیامد استقرار» تعیین گردید. در سیستم اطلاعات لیست سیاه آلمان-­اتریش (GABLIS)، قدرت تهاجمی گونه با توجه به میزان پراکنش در محدوده مورد مطالعه ارزیابی شد. گونه غیربومی تیلاپیای شکم قرمز در مدل AS-ISK، با توجه به حد آستانه منطقه ارزیابی، غربال­گری گردید و با استفاده از روش Harmonia+، میزان تهاجم گونه بر اساس احتمال استقرار و گسترش گونه و اثرات زیست­­ محیطی ناشی از آن محاسبه شد. همچنین تطبیق اقلیمی گستره بومی گونه مذکور و محدوده مورد مطالعه، با سیستم کوپن گایگر انجام شد.نتایج و بحث: نتایج پژوهش حاکی از بالا بودن رتبه احتمال قرار گرفتن گونه در مسیر معرفی، پتانسیل ورود، پتانسیل استقرار، پتانسیل گسترش و احتمال تأثیرات اقتصادی و زیست­­ محیطی در محدوده مورد مطالعه، بر طبق ارزیابی ریسک سه ملیتی، می­­ باشد. نتایج پروتکل GABLIS، نشان داد که گونه غیربومی تیلاپیا شکم قرمز به طور گسترده در منطقه ارزیابی ریسک پراکنده شده است و در لیست سیاه و زیر لیست مدیریت (b3) قرار گرفت. در ارزیابی ریسکAS-ISK ، عدد ریسک 44 شد که از حد آستانه مدل برای محدوده مورد مطالعه که برابر 5/22 است، بالاتر می ­باشد. این عدد گویای آن است که این گونه از ریسک تهاجمی بالایی در این منطقه برخوردار است. امتیاز کلی ریسک در روش Harmonia+ که تابعی از امتیاز تهاجم و تأثیرات گونه می­­ باشد برای ­گونه تیلاپیا شکم قرمز ­بالا ارزیابی گردید. بر این اساس خطر استقرار و پراکندگی این گونه در محدوده مورد مطالعه زیاد بوده و تأثیرات زیست­­ محیطی آن قابل توجه است. همچنین مشابهت بخش زیادی از طبقات اقلیمی محدوده مورد مطالعه با زیستگاه بومی گونه، حاکی از تطابق بالای اقلیمی بین محدوده مذکور و گستره بومی تیلاپیا شکم قرمز می­ باشد.نتیجه ­گیری: با توجه به اثرات منفی روز­افزون گونه ­­های غیر­بومی بر روی گونه­­ های بومی و اکوسیستم ­­ها، ضرورت استفاده از ابزارهای ارزیابی خطر بیش از پیش احساس می ­­شود. با توجه به شواهد میدانی، روش‌های ارزیابی ریسک سه ملیتی (TRAG)، سیستم اطلاعات لیست سیاه آلمان-­اتریش، ­مدل AS-ISK و­Harmonia+ به خوبی توانستند میزان تهاجمی بودن گونه‌ غیربومی تیلاپیا شکم قرمز را در حوضه‌ آبریز تالاب شادگان نشان دهند. با توجه به نتایج حاصل از ارزیابی ریسک و خطرات ناشی از این گونه به شدت توصیه می‌شود که اقدامات کنترلی و مدیریتی در سطح وسیع، با جدیت عملیاتی شود.