The role of dispersal in range change in birds

Eurasian reed warbler Acrocephalus scirpaceus expanded its range in Great Britain in the late 20th and early 21st centuries. The role of dispersal in this range expansion was investigated. Inference of the mechanisms underlying the range dynamics drew on fieldwork, analysis of large observational datasets, and a simulation model; this model was run in a reedbed map of Britain, generated from satellite data using machine learning. Breeding season temperature sets up reed warbler’s range limit in Britain directly, by influencing occupancy in the current year, perhaps mediated through reed Phragmites australis phenology. Although components of productivity were positively related to temperature, these and adult survival did not decline to the range edge. There was therefore no evidence that demography plays a role in limiting reed warbler’s range in Britain; however, not all aspects of demography were investigated. Survival was negatively related to temperature, and simulations suggested that this may allow reed warbler to maintain a more northerly range limit than without such a relationship. Reed warbler’s range expansion can be explained by a gradual equilibration with climate space, enabled by long-distance dispersal: only rare long-distance dispersing individuals matched the rate of range expansion. Reed warbler’s range edge tracked climate change, but the bulk of the population lagged behind. This could be due to dispersal-limitation, or perhaps newly established populations grow too slowly to generate sufficient emigrants. Simulations suggested that reed warbler’s range size is more sensitive to demography than to dispersal. The number of fledglings per breeding attempt increased over time, probably due to climate warming, and could have increased emigration; if so, this may be the cause of a more rapid movement in the range centroid later in the study period. Emigration, transition and immigration may therefore play different roles in reed warbler’s range dynamics in space and time

A wetland vulnerability assessment : consequences for the avian communities of saltmarshes

Understanding better the consequences of anthropogenic pressure and environmental change is a substantial area of research for modern conservation ecology. This aim of this research is to investigate these consequences for the avian communities of saltmarshes and associated reed beds. The research has four objectives: to classify saltmarsh and reed bed vegetation distribution; to assess the vulnerability of these habitats to sea level rise; to determine the impacts of sea level rise on nesting avifauna; and to derive recommendations for conservation practice.Vegetation classification methods using data from satellites and Unmanned Aerial Vehicles (UAV) for the Upper Mersey Estuary were explored. Satellite data failed to provide adequate classification due to a large spatial resolution. Object-based methods carried out on UAV data produced an accurate vegetation classification. The implications for adopting this method in a vegetation monitoring system are discussed.In 2016 a series of habitat interventions (grazing by cattle, scrape creation, and establishing a reed bed cutting 20-year cycle) on saltmarsh and reedbeds within the Upper Mersey Estuary were commenced. These interventions were maintained during the three years of this study. Changes in the ecology resulting from these interventions were monitored using the Common Bird Census technique between March and July 2015 - 2018, Wetland Bird Survey counts, and wintering bird surveys. These habitat management interventions were associated with increased diversity of wetland species (both feeding and breeding) and therefore, increased habitat connectivity with the Mersey Estuary SPA.Modelling highlighted the moderate sensitivity of saltmarsh habitats in the Upper Mersey Estuary to sea level rise. With lower sea level rise, nesting sites for all avian species were found to be restricted by periodic tidal flooding and under the top-end estimate of tidal increase (between 1.1 – 1.9 metres) the species studied would not be able to breed successfully.The findings reported here have implications for global estuarine saltmarsh management

Using remote sensing to explore the spectral and spatial characteristics of wetland vegetation.

Wetlands play an important role as ecotones between terrestrial and aquatic habitats and, as a result, represent an environment of high biodiversity and important hydrological function. Ecological understanding in these environments is hampered by difficult terrain and the dynamic and heterogeneous nature of the vegetation. Remote sensing can provide large amounts of contemporaneous data quickly, objectively and over large areas. This study utilises remote sensing data in conjunction with field data and habitat maps derived from traditional ecological surveys to investigate the use of remote sensing as a tool to aid the ecological understanding and monitoring of wetland environments. This study investigated three main objectives; the first two involved the use of field spectrometry from six habitat types in a freshwater wetland in the north of Scotland. Multivariate analyses demonstrated the possibility of distinguishing between these habitat types using field spectra alone. Detailed vegetation datasets were also collected and the relationship between these and variation in the associated spectra was investigated. Significant relationships were established between ordination axes and spectral bands in the green and NIR regions of the spectrum. Results also demonstrated the potential for remote sensing data to characterise the nature of habitat boundaries. The third objective involved the use of airborne imagery to classify remote sensing data into ecologically meaningful classes. Classification accuracies of over 70% were obtained. Work over the last decade has seen a bridging of the relationship between remote sensing and ecology although it is widely acknowledged that our ecological understanding of the remote sensing-vegetation relationship is still limited at many scales and in many ecosystems, not least the wetland environment. This study provides a much needed basis to research in this cross-disciplinary field and identifies further areas that would benefit from future work

Remote sensing methods for the biophysical characterization of protected areas globally: challenges and opportunities

Protected areas (PAs) are a key strategy to reverse global biodiversity declines, but they are under increasing pressure from anthropogenic activities and concomitant effects. Thus, the heterogeneous landscapes within PAs, containing a number of different habitats and ecosystem types, are in various degrees of disturbance. Characterizing habitats and ecosystems within the global protected area network requires large-scale monitoring over long time scales. This study reviews methods for the biophysical characterization of terrestrial PAs at a global scale by means of remote sensing (RS) and provides further recommendations. To this end, we first discuss the importance of taking into account the structural and functional attributes, as well as integrating a broad spectrum of variables, to account for the different ecosystem and habitat types within PAs, considering examples at local and regional scales. We then discuss potential variables, challenges and limitations of existing global environmental stratifications, as well as the biophysical characterization of PAs, and finally offer some recommendations. Computational and interoperability issues are also discussed, as well as the potential of cloud-based platforms linked to earth observations to support large-scale characterization of PAs. Using RS to characterize PAs globally is a crucial approach to help ensure sustainable development, but it requires further work before such studies are able to inform large-scale conservation actions. This study proposes 14 recommendations in order to improve existing initiatives to biophysically characterize PAs at a global scale

Management and protection of Mediterranean groundwater-related coastal wetlands and their service

In the framework of the GEF/UNEP-MAP Strategic Partnership for the Mediterranean Sea Large Marine Ecosystem, UNESCO-IHP executed a component on “Management of coastal aquifers and groundwater”, which included an activity on “Implementation of eco-hydrogeology applications for management and protection of coastal wetlands”. The aim of the activity was to reverse degradation trends in coastal aquifers and groundwater-related coastal wetlands and enhance human wellbeing, namely by providing appropriate capacities for the integration of an ecosystem services approach into groundwater and wetlands assessment and management. To this end, UNESCO-IHP sought the cooperation of experts in order to design and carry out actions aiming to generate a new conceptual framework integrating hydrogeological, ecosystem, and management considerations in the management of Mediterranean groundwater-related coastal wetlands. Among key actions, a background document was prepared, detailing the basic aspects to be considered for an improved management of Mediterranean groundwater-related coastal wetlands through the assessment of the interlinkages between groundwater ows, wetlands services, and human wellbeing. This book sets forth the conceptual and empirical aspects that must be examined and followed to better understand the relationships between groundwater-associated wetlands, geology, hydrology, and services to human well-being. It also presents methods for inventorying the basic information needed to characterize wetlands and aquifer functioning and to assess wetlands’ contribution to human well-being. Finally, it proposes guidelines and recommendations for the evaluation and integrated management of Mediterranean groundwater-related coastal wetlands in order to preserve the sustaining role of groundwater in relation the many environmental services that wetlands provide.Global Environmental Facility (GEF) United Nations Environmental Programme/Mediterranean Action Plan (UNEP/MAP

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions

Applications of satellite ‘hyper-sensing’ in Chinese agriculture:Challenges and opportunities

Ensuring adequate food supplies to a large and increasing population continues to be the key challenge for China. Given the increasing integration of China within global markets for agricultural products, this issue is of considerable significance for global food security. Over the last 50 years, China has increased the production of its staple crops mainly by increasing yield per unit land area. However, this has largely been achieved through inappropriate agricultural practices, which have caused environmental degradation, with deleterious consequences for future agricultural productivity. Hence, there is now a pressing need to intensify agriculture in China using practices that are environmentally and economically sustainable. Given the dynamic nature of crops over space and time, the use of remote sensing technology has proven to be a valuable asset providing end-users in many countries with information to guide sustainable agricultural practices. Recently, the field has experienced considerable technological advancements reflected in the availability of ‘hyper-sensing’ (high spectral, spatial and temporal) satellite imagery useful for monitoring, modelling and mapping of agricultural crops. However, there still remains a significant challenge in fully exploiting such technologies for addressing agricultural problems in China. This review paper evaluates the potential contributions of satellite ‘hyper-sensing’ to agriculture in China and identifies the opportunities and challenges for future work. We perform a critical evaluation of current capabilities in satellite ‘hyper-sensing’ in agriculture with an emphasis on Chinese sensors. Our analysis draws on a series of in-depth examples based on recent and on-going projects in China that are developing ‘hyper-sensing’ approaches for (i) measuring crop phenology parameters and predicting yields; (ii) specifying crop fertiliser requirements; (iii) optimising management responses to abiotic and biotic stress in crops; (iv) maximising yields while minimising water use in arid regions; (v) large-scale crop/cropland mapping; and (vi) management zone delineation. The paper concludes with a synthesis of these application areas in order to define the requirements for future research, technological innovation and knowledge exchange in order to deliver yield sustainability in China