Invasion of freshwater ecosystems is promoted by network connectivity to hotspots of human activity

Aim: Hotspots of human activity are focal points for ecosystem disturbance and non‐native introduction, from which invading populations disperse and spread. As such, connectivity to locations used by humans may influence the likelihood of invasion. Moreover, connectivity in freshwater ecosystems may follow the hydrological network. Here we tested whether multiple forms of connectivity to human recreational activities promotes biological invasion of freshwater ecosystems. Location: England, UK. Time period: 1990–2018. Major taxa studied: One hundred and twenty‐six non‐native freshwater birds, crustaceans, fish, molluscs and plants. Methods: Machine learning was used to predict spatial gradients in human recreation and two high risk activities for invasion (fishing and water sports). Connectivity indices were developed for each activity, in which human influence decayed from activity hotspots according to Euclidean distance (spatial connectivity) or hydrological network distance (downstream, upstream and along‐channel connectivity). Generalized linear mixed models identified the connectivity type most associated to invasive species richness of each group, while controlling for other anthropogenic and environmental drivers. Results: Connectivity to humans generally had stronger positive effects on invasion than all other drivers except recording effort. Recreation had stronger influence than urban land cover, and for most groups high risk activities had stronger effects than general recreation. Downstream human connectivity was most important for invasion by most of the groups, potentially reflecting predominantly hydrological dispersal. An exception was birds, for which spatial connectivity was most important, possibly because of overland dispersal capacity. Main conclusions: These findings support the hypothesis that freshwater invasion is partly determined by an interaction between human activity and species dispersal in the hydrological network. By comparing alternative connectivity types for different human activities, our approach could enable robust inference of specific pathways and spread mechanisms associated with particular taxa. This would provide evidence to support better prioritization of surveillance and management for invasive non‐native species

Biodiversity, cultural pathways, and human health: a framework.

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Direct contact with biodiversity is culturally important in a range of contexts. Many people even join conservation organisations to protect biodiversity that they will never encounter first-hand. Despite this, we have little idea how biodiversity affects people's well-being and health through these cultural pathways. Human health is sensitive to apparently trivial psychological stimuli, negatively affected by the risk of environmental degradation, and positively affected by contact with natural spaces. This suggests that well-being and health should be affected by biodiversity change, but few studies have begun to explore these relationships. Here, we develop a framework for linking biodiversity change with human cultural values, well-being, and health. We argue that better understanding these relations might be profoundly important for biodiversity conservation and public health.Natural Environment Research CouncilEuropean Regional Development Fund Programme 2007 to 2013European Social Fund Convergence Programme for Cornwall and the Isles of Scilly

Assessing the ecological coherence of a marine protected area network in the Celtic Seas

Marine protected areas (MPAs) are a management tool used to respond to human-derived threats in marine ecosystems. Historically, MPAs have been established on an individual ad hoc basis, rather than through a systematic, planned process. However, high levels of functional and spatial connectivity within marine ecosystems have led to the suggestion that networks of MPAs provide greater ecological benefits than individual MPAs. Consequently, international policy has developed to consider broader spatial requirements for marine conservation, resulting in a number of international and regional agreements that require the establishment of ecologically coherent MPA networks. Existing MPAs are now being considered, retrospectively, alongside new designations, as networks of MPAs across regions, both nationally and internationally. Under the Marine Strategy Framework Directive (MSFD), France, the Republic of Ireland, and the UK (including Northern Ireland and the Isle of Man) are required to work together to ensure coordinated development of marine strategies for the Celtic Seas subregion. Accordingly, MPAs have been identified as crucial components of the programme of measures to achieve Good Environmental Status (GES) under the MSFD. Here, we provide the first ecological coherence assessment of an MPA network spanning an MSFD subregion. A network of 533 MPAs, or parts thereof, across the Celtic Seas subregion was assessed using five criteria and two methodologies, with a focus on broadscale habitats. While the Celtic Seas MPA network as a whole is not ecologically coherent (according to accepted thresholds), progress toward a number of global targets has been achieved, for example, protection of 10% of marine and coastal areas under the Convention on Biological Diversity. Further, all MSFD predominant habitat types assessed are adequately represented and replicated within the network. However, a number of gaps were identified, including a lack of MPAs in offshore and deeper areas, and inadequate proportions of predominant habitat types within MPAs. Addressing these gaps to enable the MPA network to fulfill its critical role in the delivery of GES under the MSFD will require both national progress toward designation of adequate and viable MPAs and transboundary agreements and coordination of MPA designation processes at the European level

Environmental Systems and Local Actors: Decentralizing Environmental Policy in Uganda

In Uganda, environmental and natural resource management is decentralized and has been the responsibility of local districts since 1996. This environmental management arrangement was part of a broader decentralization process and was intended to increase local ownership and improve environmental policy; however, its implementation has encountered several major challenges over the last decade. This article reviews some of the key structural problems facing decentralized environmental policy in this central African country and examines these issues within the wider framework of political decentralization. Tensions have arisen between technical staff and politicians, between various levels of governance, and between environmental and other policy domains. This review offers a critical reflection on the perspectives and limitations of decentralized environmental governance in Uganda. Our conclusions focus on the need to balance administrative staff and local politicians, the mainstreaming of local environmental policy, and the role of international donors

Competing coalitions: The politics of renewable energy and fossil fuels in Mexico, South Africa and Thailand

This paper analyses why middle-income countries incentivize renewable energy despite inexpensive domestic fossil fuel resources and lack of international support. We examine the politics of renewable energy programs in Mexico, South Africa and Thailand. All three countries hold abundant local fossil fuel and renewable energy resources. We argue that renewable energy programs become implementable policy options in fossil fuel resource-rich middle-income countries when coalitions of powerful political actors support them. This study presents an analysis of the domestic coalitions in support of and those in opposition to renewable energy policies from a discourse network perspective. Discourse networks reflect actors and the arguments they share to advance or hamper the policy process. The analysis draws on a data set of 560 coded statements in support or opposition of renewable energy from media articles, policy documents and interviews. Findings show similar structures of competing coalitions in all three countries, with the discourse in all three countries revealing strong linkages between environmental and economic considerations

Natural archives of long-range transported contamination at the remote lake Letšeng-la Letsie, Maloti Mountains, Lesotho

Naturally accumulating archives, such as lake sediments and wetland peats, in remote areas may be used to identify the scale and rates of atmospherically deposited pollutant inputs to natural ecosystems. Co-located lake sediment and wetland cores were collected from Letšeng-la Letsie, a remote lake in the Maloti Mountains of southern Lesotho. The cores were radiometrically dated and analysed for a suite of contaminants including trace metals and metalloids (Hg, Pb, Cu, Ni, Zn, As), fly-ash particles, stable nitrogen isotopes, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs) and hexachlorobenzene (HCB). While most trace metals showed no recent enrichment, mercury, fly-ash particles, high molecular weight PAHs and total PCBs showed low but increasing levels of contamination since c.1970, likely the result of long-range transport from coal combustion and other industrial sources in the Highveld region of South Africa. However, back-trajectory analysis revealed that atmospheric transport from this region to southern Lesotho is infrequent and the scale of contamination is low. To our knowledge, these data represent the first palaeolimnological records and the first trace contaminant data for Lesotho, and one of the first multi-pollutant historical records for southern Africa. They therefore provide a baseline for future regional assessments in the context of continued coal combustion in South Africa through to the mid-21st century

The context dependence of frontier versus wilderness conservation priorities

Much of conservation planning has focused on how we should prioritize areas for protection based on biodiversity and cost, but less is known about how we should prioritize areas based upon the level of threat they face. We discuss two opposing threat prioritization strategies: frontier conservation (prioritizing high‐threat areas) and wilderness conservation (prioritizing low‐threat areas). Using a temporally explicit model, we demonstrate that the best strategy depends on a variety of factors, including protection costs, heterogeneity in biodiversity, biodiversity–area relationships, the rate of biodiversity recovery, the rate of change in threats through time, and the timeframe within which we measure conservation outcomes. By quantitatively comparing the impact of these strategies, we aim to shift the debate away from a simple dichotomy of frontier versus wilderness, toward an understanding of the context‐specific benefits of each option, and a discussion of how threat combines with other factors to determine spatial conservation priorities