Including Methane Emissions from Agricultural Ponds in National Greenhouse Gas Inventories.

Agricultural ponds are a significant source of greenhouse gases, contributing to the ongoing challenge of anthropogenic climate change. Nations are encouraged to account for these emissions in their national greenhouse gas inventory reports. We present a remote sensing approach using open-access satellite imagery to estimate total methane emissions from agricultural ponds that account for (1) monthly fluctuations in the surface area of individual ponds, (2) rates of historical accumulation of agricultural ponds, and (3) the temperature dependence of methane emissions. As a case study, we used this method to inform the 2024 National Greenhouse Gas Inventory reports submitted by the Australian government, in compliance with the Paris Agreement. Total annual methane emissions increased by 58% from 1990 (26 kilotons CH4 year-1) to 2022 (41 kilotons CH4 year-1). This increase is linked to the water surface of agricultural ponds growing by 51% between 1990 (115 kilo hectares; 1,150 km2) and 2022 (173 kilo hectares; 1,730 km2). In Australia, 16,000 new agricultural ponds are built annually, expanding methane-emitting water surfaces by 1,230 ha yearly (12.3 km2 year-1). On average, the methane flux of agricultural ponds in Australia is 0.238 t CH4 ha-1 year-1. These results offer policymakers insights into developing targeted mitigation strategies to curb these specific forms of anthropogenic emissions. For instance, financial incentives, such as carbon or biodiversity credits, can mobilize widespread investments toward reducing greenhouse gas emissions and enhancing the ecological and environmental values of agricultural ponds. Our data and modeling tools are available on a free cloud-based platform for other countries to adopt this approach.

Wetland water quality patterns and anthropogenic pressure associations across the continental USA.

Anthropogenic impacts on lake and stream water quality are well established but have been much less studied in wetlands. Here we use data from the 2016 National Wetland Condition Assessment to characterize water quality and its relationship to anthropogenic pressure for inland wetlands across the conterminous USA. Water samples obtained from 525 inland wetlands spanned pH from <4 to >9 and 3 to 5 orders of magnitude in ionic strength (chloride, sulfate, conductivity), nutrients (total N and P), turbidity, planktonic chlorophyll, and dissolved organic carbon (DOC). Anthropogenic pressure levels were evaluated at two spatial scales - an adjacent scale scored from field checklists, and a catchment scale indicated by percent agricultural plus urban landcover. Pressure at the two spatial scales were uncorrelated and varied considerably across regions and wetland hydrogeomorphic types. Both adjacent- and catchment-scale pressure were associated with elevated ionic-strength metrics; chloride elevation was most evident in road-salt using states, and sulfate was strongly elevated in a few sites with coal mining nearby. Nutrients were elevated in association with catchment-scale pressure but concomitant changes were not seen in planktonic chlorophyll. Acidic pH and high DOC occurred primarily in upper Great Lakes and eastern seaboard sites having low anthropogenic pressure, suggesting natural organic acid sources. Ionic strength and nutrients increased with increasing catchment-scale pressure even in Flats and closed Depression and Lacustrine sites, which indicates connectivity to rather than isolation from upland anthropogenic landuse even for wetlands lacking inflowing streams.

Headwater streams and inland wetlands: Status and advancements of geospatial datasets and maps across the United States.

Headwater streams and inland wetlands provide essential functions that support healthy watersheds and downstream waters. However, scientists and aquatic resource managers lack a comprehensive synthesis of national and state stream and wetland geospatial datasets and emerging technologies that can further improve these data. We conducted a review of existing United States (US) federal and state stream and wetland geospatial datasets, focusing on their spatial extent, permanence classifications, and current limitations. We also examined recent peer-reviewed literature for emerging methods that can potentially improve the estimation, representation, and integration of stream and wetland datasets. We found that federal and state datasets rely heavily on the US Geological Survey's National Hydrography Dataset for stream extent and duration information. Only eleven states (22%) had additional stream extent information and seven states (14%) provided additional duration information. Likewise, federal and state wetland datasets primarily use the US Fish and Wildlife Service's National Wetlands Inventory (NWI) Geospatial Dataset, with only two states using non-NWI datasets. Our synthesis revealed that LiDAR-based technologies hold promise for advancing stream and wetland mapping at limited spatial extents. While machine learning techniques may help to scale-up these LiDAR-derived estimates, challenges related to preprocessing and data workflows remain. High-resolution commercial imagery, supported by public imagery and cloud computing, may further aid characterization of the spatial and temporal dynamics of streams and wetlands, especially using multi-platform and multi-temporal machine learning approaches. Models integrating both stream and wetland dynamics are limited, and field-based efforts must remain a key component in developing improved headwater stream and wetland datasets. Continued financial and partnership support of existing databases is also needed to enhance mapping and inform water resources research and policy decisions.

Tidal organic input restricts CO2 sequestration capacity of estuarine wetlands.

The inland and estuary wetlands that characterized by different natural environment perform distinctly in soil carbon (C) sink. It was deemed that estuary wetland has a higher organic C accumulation rate than inland wetland, due to its higher primary production and tidal organics input, thus having higher organic C sink capacity. While from CO2 budge in view, whether does the large organic input from tide restrict CO2 sequestration capacity of estuary wetland has not been discussed comparing with inland wetland. In this study, inland and estuary wetlands were selected to study the potential of CO2 sequestration capacity. It was found that inland wetland had most of soil organic carbon (SOC) derived from plant C, which brought remarkable organic C content and nourished higher microbial biomass, dehydrogenase, and ß_glucosidase than estuary wetland. The estuary wetland instead accumulated less SOC, a considerable proportion of which came from tidal waters, therefore supporting lower microbial biomass and enzyme activities than that in inland wetland. However, estuary wetland was evaluated having higher capability in SOC mineralization than inland wetland in consideration of soil respiration (SR) and SR quotient. It was concluded that tidal organic C accelerated the SOC mineralization in estuarine wetland, thus weakening the CO2 sequestration. These results implied the importance of pollution control for reservation CO2 sink function in estuarine wetland.

Lake productivity and waterbird functional diversity across geographic and environmental gradients in temperate China.

Geographical gradients in species diversity have long fascinated biogeographers and ecologists. However, the extent and generality of the effects of the important factors governing functional diversity (FD) patterns are still debated, especially for the freshwater domain. We examined the relationship between lake productivity and functional diversity of waterbirds sampled from 35 lakes and reservoirs in northern China with a geographic coverage of over 5 million km2. We used structural equation modeling (SEM) to explore the causal relationships between geographic position, climate, lake productivity, and waterbird FD. We found unambiguous altitudinal and longitudinal gradients in lake productivity and waterbird FD, which were strongly mediated by local environmental factors. Specifically, we found (a) lake productivity increased northeast and decreased with altitude. The observed geographic and altitudinal gradients were driven by climatic conditions and nutrient availability, which collectively explained 93% of the variations in lake productivity; (b) waterbird FD showed similar geographic and altitudinal gradients; the environmental factors which had direct and/or indirect effects on these gradients included climate and lake area, which collectively explained more than 39% of the variation in waterbird FD; and 3) a significant (p = .029) causality between lake productivity and waterbird FD was confirmed. Nevertheless, the causality link was relatively weak in comparison with climate and lake area (the standardized path coefficient was 0.55, 0.23, and 0.03 for climate, lake area, and productivity, respectively). Our study demonstrates how the application of multivariate technique (e.g., SEM) enables the illustration of complex causal paths in ecosystems, enhancing mechanistic explanations that underlie the observed broadscale biodiversity gradients.

Spatiotemporal diversity, structure and trophic guilds of insect assemblages in a semi-arid Sabkha ecosystem.

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, of which Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different stations of the wetland and seasons.

A conceptual model to understand the drivers of change in tropical wetlands: a comparative assessment in India and Brazil / Un modelo conceptual para comprender los impulsores del cambio en los humedales tropicales: una evaluación comparativa en India y Brasil

Tropical wetlands are amongst the most biodiverse ecosystems on Earth and have immense socio-ecological value. However, tropical wetlands are considered exploitable resources and continue to be drained and converted to other "productive" uses. It is therefore urgent to identify and understand the interactions between various drivers of change triggering degradation of such wetlands. In the present study, we systematically reviewed and analyzed the existing literature on wetlands in two tropical countries namely India and Brazil with special reference to inland wetlands, and proposed a conceptual model illustrating the intricate linkages of such wetlands with different drivers of change. We also developed the Nature Futures' Framework to depict the diverse values of inland wetlands contributing to human wellbeing in the two tropical countries. Findings revealed similar drivers of change triggering the degradation of Indian and Brazilian wetlands. These include changes in climate & land use, population growth, poor land governance due to weak policies, besides other anthropogenic activities such as deforestation, and overexploitation of wetland resources. Among these, land-use change such as agriculture intensification and infrastructure development were the major direct drivers; whereas, institutional and governance factors such as the absence of concrete policy measures were the major indirect drivers threatening the inland wetlands in India and Brazil. Results also revealed some contrasting drivers of change such as illegal human settlements, and land grabbing by the brick industry for Indian wetlands; while, gold mining and intensification of bovine systems for Brazilian wetlands. Our paper also provides an insight into the status of wetland conservation in India and Brazil. We recommend the promotion of community-based conservation practices while adopting sustainable livelihood strategies by the local people for the conservation and wise use of inland wetlands in India and Brazil. The arguments raised in the paper have the potential to assist the stakeholders and/or decision-makers towards implementing sustainable management strategies for inland wetlands in the two countries, and tropical wetlands in general.

Los humedales tropicales se encuentran entre los ecosistemas con mayor biodiversidad en la Tierra y tienen un inmenso valor socioecológico. Sin embargo, los humedales tropicales se consideran recursos exploTables y continúan siendo drenados y convertidos a otros usos "productivos". Por lo tanto, es urgente identificar y comprender las interacciones entre varios impulsores del cambio que desencadenan la degradación de dichos humedales. En el presente estudio, revisamos y analizamos sistemáticamente la literatura existente sobre humedales en dos países tropicales, a saber, India y Brasil, con especial referencia a los humedales continentales, y propusimos un modelo conceptual que ilustra el intrincado vínculo de dichos humedales con diferentes impulsores del cambio. También desarrollamos el Marco de Nature Futures para resaltar los diversos valores de los humedales continentales de India y Brasil que contribuyen al bienestar humano en los dos países tropicales. Los resultados revelaron impulsores similares de los cambios que desencadenan la degradación de los humedales de la India y Brasil, incluidos los cambios en el clima y el uso de la tierra, el crecimiento de la población, las políticas débiles y la mala gobernanza de la tierra, además de otras actividades antropogénicas como la deforestación y la sobreexplotación de recursos. Entre estos, el cambio en el uso de la tierra, como la intensificación de la agricultura y el desarrollo de infraestructura, fueron los principales impulsores directos, mientras que los factores institucionales y de gobernanza, como la ausencia de medidas políticas concretas, fueron el principal impulsor indirecto que amenazó los humedales continentales de India y Brasil. Los resultados también revelaron algunos factores de cambio contrastantes, como los asentamientos humanos ilegales y el acaparamiento de tierras por parte de la industria del ladrillo para los humedales indios; mientras que la extracción de oro y la intensificación de los sistemas bovinos para los humedales brasileños. Nuestro documento también proporciona una visión sobre el estado de la conservación de humedales en India y Brasil. Recomendamos la promoción de prácticas de conservación basadas en la comunidad al adoptar estrategias de medios de vida sostenibles por parte de la población local para la conservación y el uso racional de los humedales continentales en India y Brasil. Los argumentos planteados en el artículo tienen el potencial de ayudar a las partes interesadas y / o los tomadores de decisiones para implementar estrategias de gestión sostenible para los humedales continentales en los dos países, y para los humedales tropicales en general.

A conceptual model to understand the drivers of change in tropical wetlands: a comparative assessment in India and Brazil / Un modelo conceptual para comprender los impulsores del cambio en los humedales tropicales: una evaluación comparativa en India y Brasil

Abstract: Tropical wetlands are amongst the most biodiverse ecosystems on Earth and have immense socio-ecological value. However, tropical wetlands are considered exploitable resources and continue to be drained and converted to other "productive" uses. It is therefore urgent to identify and understand the interactions between various drivers of change triggering degradation of such wetlands. In the present study, we systematically reviewed and analyzed the existing literature on wetlands in two tropical countries namely India and Brazil with special reference to inland wetlands, and proposed a conceptual model illustrating the intricate linkages of such wetlands with different drivers of change. We also developed the Nature Futures' Framework to depict the diverse values of inland wetlands contributing to human wellbeing in the two tropical countries. Findings revealed similar drivers of change triggering the degradation of Indian and Brazilian wetlands. These include changes in climate & land use, population growth, poor land governance due to weak policies, besides other anthropogenic activities such as deforestation, and overexploitation of wetland resources. Among these, land-use change such as agriculture intensification and infrastructure development were the major direct drivers; whereas, institutional and governance factors such as the absence of concrete policy measures were the major indirect drivers threatening the inland wetlands in India and Brazil. Results also revealed some contrasting drivers of change such as illegal human settlements, and land grabbing by the brick industry for Indian wetlands; while, gold mining and intensification of bovine systems for Brazilian wetlands. Our paper also provides an insight into the status of wetland conservation in India and Brazil. We recommend the promotion of community-based conservation practices while adopting sustainable livelihood strategies by the local people for the conservation and wise use of inland wetlands in India and Brazil. The arguments raised in the paper have the potential to assist the stakeholders and/or decision-makers towards implementing sustainable management strategies for inland wetlands in the two countries, and tropical wetlands in general.

Resumen: Los humedales tropicales se encuentran entre los ecosistemas con mayor biodiversidad en la Tierra y tienen un inmenso valor socioecológico. Sin embargo, los humedales tropicales se consideran recursos exploTables y continúan siendo drenados y convertidos a otros usos "productivos". Por lo tanto, es urgente identificar y comprender las interacciones entre varios impulsores del cambio que desencadenan la degradación de dichos humedales. En el presente estudio, revisamos y analizamos sistemáticamente la literatura existente sobre humedales en dos países tropicales, a saber, India y Brasil, con especial referencia a los humedales continentales, y propusimos un modelo conceptual que ilustra el intrincado vínculo de dichos humedales con diferentes impulsores del cambio. También desarrollamos el Marco de Nature Futures para resaltar los diversos valores de los humedales continentales de India y Brasil que contribuyen al bienestar humano en los dos países tropicales. Los resultados revelaron impulsores similares de los cambios que desencadenan la degradación de los humedales de la India y Brasil, incluidos los cambios en el clima y el uso de la tierra, el crecimiento de la población, las políticas débiles y la mala gobernanza de la tierra, además de otras actividades antropogénicas como la deforestación y la sobreexplotación de recursos. Entre estos, el cambio en el uso de la tierra, como la intensificación de la agricultura y el desarrollo de infraestructura, fueron los principales impulsores directos, mientras que los factores institucionales y de gobernanza, como la ausencia de medidas políticas concretas, fueron el principal impulsor indirecto que amenazó los humedales continentales de India y Brasil. Los resultados también revelaron algunos factores de cambio contrastantes, como los asentamientos humanos ilegales y el acaparamiento de tierras por parte de la industria del ladrillo para los humedales indios; mientras que la extracción de oro y la intensificación de los sistemas bovinos para los humedales brasileños. Nuestro documento también proporciona una visión sobre el estado de la conservación de humedales en India y Brasil. Recomendamos la promoción de prácticas de conservación basadas en la comunidad al adoptar estrategias de medios de vida sostenibles por parte de la población local para la conservación y el uso racional de los humedales continentales en India y Brasil. Los argumentos planteados en el artículo tienen el potencial de ayudar a las partes interesadas y / o los tomadores de decisiones para implementar estrategias de gestión sostenible para los humedales continentales en los dos países, y para los humedales tropicales en general.