Dyke demolition led to a sharp decline in waterbird diversity due to reduction in habitat quality: A case study of Dongting Lake, China

Waterbird responses to habitat changes are of great concern in ecology. Dongting Lake is the second-largest freshwater lake in China, and its vast wetland area provides an important wintering habitat for migratory waterbirds of the East Asian–Australasian Flyway. However, lake reclamation and illegal human-made dykes have degraded the Dongting Lake wetland area at different degrees in the recent decades, seriously threatening the ecology of this area. In 2017, to restore the natural properties of Dongting Lake, the Chinese government completely demolished 459 dykes and preserved 14 dykes for various purposes (biodiversity conservation and flood control). However, the direct impact of dyke demolition on wintering waterbirds has not been comprehensively assessed. In this study, based on annual (2013/14–2020/21) waterbird census data, we compared the differences in species composition of waterbirds in the dyke-demolished and dyke-preserved areas. The results indicated that waterbird diversity, in terms of species number, abundance, the proportion of abundance, number of rare waterbirds species, and exclusive species, was higher in the dyke preserved areas than in the previously demolished areas. Species turnover and reordering further identified dynamic differences in the spatial and temporal distributions of waterbirds. Therefore, we used long-term habitat data to explore whether habitat changes were responsible for the changes in waterbirds; the results showed significantly decreased water and mudflat areas, but a significantly increased vegetation area in the dyke-demolished areas. The water area was significantly positively correlated with waterbirds in this habitat. Compared to the dyke-demolished areas, the stable and suitable habitat area in the dyke-preserved areas might be closely related to the higher waterbird diversity. Our study revealed habitat changes in the context of large-scale dyke demolition in Dongting Lake and demonstrated the dynamic response of waterbirds to habitat changes.

Long-term trends in the occupancy of ants revealed through use of multi-sourced datasets

We combined participatory science data and museum records to understand long-term changes in occupancy for 29 ant species in Denmark over 119 years. Bayesian occupancy modelling indicated change in occupancy for 15 species: five increased, four declined and six showed fluctuating trends. We consider how trends may have been influenced by life-history and habitat changes. Our results build on an emerging picture that biodiversity change in insects is more complex than implied by the simple insect decline narrative.

Metapopulation capacity determines food chain length in fragmented landscapes

Metapopulation capacity provides an analytic tool to quantify the impact of landscape configuration on metapopulation persistence, which has proven powerful in biological conservation. Yet surprisingly few efforts have been made to apply this approach to multispecies systems. Here, we extend metapopulation capacity theory to predict the persistence of trophically interacting species. Our results demonstrate that metapopulation capacity could be used to predict the persistence of trophic systems such as prey–predator pairs and food chains in fragmented landscapes. In particular, we derive explicit predictions for food chain length as a function of metapopulation capacity, top-down control, and population dynamical parameters. Under certain assumptions, we show that the fraction of empty patches for the basal species provides a useful indicator to predict the length of food chains that a fragmented landscape can support and confirm this prediction for a host–parasitoid interaction. We further show that the impact of habitat changes on biodiversity can be predicted from changes in metapopulation capacity or approximately by changes in the fraction of empty patches. Our study provides an important step toward a spatially explicit theory of trophic metacommunities and a useful tool for predicting their responses to habitat changes.

The global threat from plastic pollution

Plastic pollution accumulating in an area of the environment is considered “poorly reversible” if natural mineralization processes occurring there are slow and engineered remediation solutions are improbable. Should negative outcomes in these areas arise as a consequence of plastic pollution, they will be practically irreversible. Potential impacts from poorly reversible plastic pollution include changes to carbon and nutrient cycles; habitat changes within soils, sediments, and aquatic ecosystems; co-occurring biological impacts on endangered or keystone species; ecotoxicity; and related societal impacts. The rational response to the global threat posed by accumulating and poorly reversible plastic pollution is to rapidly reduce plastic emissions through reductions in consumption of virgin plastic materials, along with internationally coordinated strategies for waste management.

Assessing soil health by measuring fauna

This chapter provides examples of the impact of soil fauna on soil health within different ecosystems and how the soil habitat changes in relation to this biodiversity. It focuses specifically on mesofauna in agriculture, grasslands, woodlands and as bioindicators, before concluding with an overview of how the development of mesofauna as bioindicators is important in establishing a healthy soil.

ECOLOGIA DE PEIXES EM RIACHOS URBANOS

The development of agriculture allowed humans to congregate in settlements which developed into the modern urban societies. This urbanization process caused profound habitat changes, giving rise to urban ecosystems where the structure, functioning and the dynamics of the ecosystem are determined by human activities. Despite the increasing rates of urbanization worldwide,the ecology of urban ecosystems is poorly known. In this chapter, we focus on urban stream ecosystems to expose the current advances in urban fish ecology. We explore topics concerning urban fish biodiversity,ecological interactions and adaptation to urban systems. We also explore different approaches and methodologies for the study of urban fish. Our goal is to introduce the theoretical background and analytical tools to study urban fishes with the intent of facilitating future research

Climate change drives widespread shifts in lake thermal habitat

Lake surfaces are warming worldwide, raising concerns about lake organism responses to thermal habitat changes. Species may cope with temperature increases by shifting their seasonality or their depth to track suitable thermal habitats, but these responses may be constrained by ecological interactions, life histories or limiting resources. Here we use 32 million temperature measurements from 139 lakes to quantify thermal habitat change (percentage of non-overlap) and assess how this change is exacerbated by potential habitat constraints. Long-term temperature change resulted in an average 6.2% non-overlap between thermal habitats in baseline (1978–1995) and recent (1996–2013) time periods, with non-overlap increasing to 19.4% on average when habitats were restricted by season and depth. Tropical lakes exhibited substantially higher thermal non-overlap compared with lakes at other latitudes. Lakes with high thermal habitat change coincided with those having numerous endemic species, suggesting that conservation actions should consider thermal habitat change to preserve lake biodiversity.