羟氨苄青霉素引起大疱性类天疱疮样疹

In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in
the world’s lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only
2.3% of the Earth’s surface, these ecosystems host at least 9.5% of the Earth’s described animal species. Furthermore,
using the World Wide Fund for Nature’s Living Planet Index, freshwater population declines (83% between 1970 and
2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought
multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats
to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii)
e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging
contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation;
(xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes,
plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes.
In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However,
we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows,
environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies,managed
relocation of species) that have been met with varying levels of success.Moving forward, we advocate hybrid approaches
that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and
ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap
between the aspirations of conservation biologists and the accelerating rate of species endangerment.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/brv.12480

Emerging threats and persistent conservation challenges for freshwater biodiversity

Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them. A comprehensive assessment of the world’s rivers and their connectivity shows that only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length.

/pdf/mapping-the-world-s-free-flowing-rivers-4lqf6zl99v.pdf

Mapping the world’s free-flowing rivers

The world's most biodiverse river basins—the Amazon, Congo, and Mekong—are experiencing an unprecedented boom in construction of hydropower dams. These projects address important energy needs, but advocates often overestimate economic benefits and underestimate far-reaching effects on biodiversity and critically important fisheries. Powerful new analytical tools and high-resolution environmental data can clarify trade-offs between engineering and environmental goals and can enable governments and funding institutions to compare alternative sites for dam building. Current site-specific assessment protocols largely ignore cumulative impacts on hydrology and ecosystem services as ever more dams are constructed within a watershed ( 1 ). To achieve true sustainability, assessments of new projects must go beyond local impacts by accounting for synergies with existing dams, as well as land cover changes and likely climatic shifts ( 2 , 3 ). We call for more sophisticated and holistic hydropower planning, including validation of technologies intended to mitigate environmental impacts. Should anything less be required when tampering with the world's great river ecosystems?

/pdf/balancing-hydropower-and-biodiversity-in-the-amazon-congo-3nstcqsc34.pdf

Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong

Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002–2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, climate change or combinations thereof. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango Delta. Others are consistent with climate model predictions. This observation-based assessment of how the world’s water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security.

/pdf/emerging-trends-in-global-freshwater-availability-73pgdps0j7.pdf

Emerging trends in global freshwater availability.

Human population growth, economic development, climate change, and the need to close the electricity access gap have stimulated the search for new sources of renewable energy. In response to this need, major new initiatives in hydropower development are now under way. At least 3,700 major dams, each with a capacity of more than 1 MW, are either planned or under construction, primarily in countries with emerging economies. These dams are predicted to increase the present global hydroelectricity capacity by 73 % to about 1,700 GW. Even such a dramatic expansion in hydropower capacity will be insufficient to compensate for the increasing electricity demand. Furthermore, it will only partially close the electricity gap, may not substantially reduce greenhouse gas emission (carbon dioxide and methane), and may not erase interdependencies and social conflicts. At the same time, it is certain to reduce the number of our planet’s remaining free-flowing large rivers by about 21 %. Clearly, there is an urgent need to evaluate and to mitigate the social, economic, and ecological ramifications of the current boom in global dam construction.

A global boom in hydropower dam construction

The rapid erosion of biodiversity is among the biggest challenges human society is facing. Concurrently, major efforts are in place to quantify changes in biodiversity, to understand the consequences for ecosystem functioning and human wellbeing, and to develop sustainable management strategies. Based on comprehensive bibliometric analyses covering 134,321 publications, we report systematic spatial biases in biodiversity-related research. Research is dominated by wealthy countries, while major research deficits occur in regions with disproportionately high biodiversity as well as a high share of threatened species. Similarly, core scientists, who were assessed through their publication impact, work primarily in North America and Europe. Though they mainly exchange and collaborate across locations of these two continents, the connectivity among them has increased with time. Finally, biodiversity-related research has primarily focused on terrestrial systems, plants, and the species level, and is frequently conducted in Europe and Asia by researchers affiliated with European and North American institutions. The distinct spatial imbalances in biodiversity research, as demonstrated here, must be filled, research capacity built, particularly in the Global South, and spatially-explicit biodiversity data bases improved, curated and shared.

/pdf/spatial-and-topical-imbalances-in-biodiversity-research-3mugqx9r0o.pdf

Spatial and topical imbalances in biodiversity research.

Biological field stations (BFS) constitute a global network for long-term environmental monitoring and research, education, and public information. On the basis of a comprehensive inventory, we identified 1268 contemporary BFS, located in 120 countries. BFS occur in all biomes and cover terrestrial, freshwater, and marine systems, with the majority situated in protected areas. We emphasize the pivotal role that BFS constitute as a strategic infrastructure of global relevance for environmental research and monitoring and discuss their future development.

/pdf/biological-field-stations-a-global-infrastructure-for-2s1zgmzmjp.pdf

Biological Field Stations: A Global Infrastructure for Research, Education, and Public Engagement

Freshwaters are among the most diverse and dynamic ecosystems globally, while also being among the most threatened systems. Freshwater biological field stations (FW‐BFS) are key facilities for research, monitoring, and education. However, high quality data and information on the status and roles of FW‐BFS are lacking. Based on the results of a questionnaire, we present information on the current situation of 134 FW‐BFS around the world. The results show that FW‐BFS conduct more short‐term (1,335) than long‐term research projects (583), offer programmes for visiting researchers, and collaborate within networks and among each other, as well as with educational, non‐governmental, and governmental stakeholders. However, FW‐BFS report a lack of sustainable funding and emphasize maintenance and expansion of research facilities and equipment as key challenges. At the same time, FW‐BFS envision an expansion of their current research scope, as well as an increase in their public visibility. Adequate financial support for FW‐BFS is a prerequisite to pursue research programmes at local, regional, and global scales, foster outreach activities, attract staff and visitors, maintain their infrastructure, and strengthen their collaboration activities.

A global survey of freshwater biological field stations

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lob.10133

Laura Tydecks

Papers

A global boom in hydropower dam construction

Spatial and topical imbalances in biodiversity research.

Biological Field Stations: A Global Infrastructure for Research, Education, and Public Engagement

A global survey of freshwater biological field stations

Global Database on Biological Field Stations a pivotal infrastructure for environmental research, education and public information