This study finds that non‐native species and warming temperatures have significant negative effects on Arctic char Salvelinus alpinus abundance in Irish lakes. Eutrophication was not important at the ...range of total phosphorus tested (0.005–0.023 mg l−1). Model results predict that S. alpinus occur across the temperature range sampled (8.2–19.7°C) when non‐natives are absent, but S. alpinus catch is predicted to be close to zero irrespective of temperature when non‐native catch is high. This result indicates that to persist, S. alpinus may require a habitat where non‐natives are at low abundance or absent. Salvelinus alpinus segregated from other species along the thermal axis, inhabiting significantly colder water and actively avoided non‐native species, which appeared to limit their distribution. The thermal niche realized by S. alpinus in non‐native dominated lakes was thus compressed relative to native dominated lakes and S. alpinus population density was significantly lower. These findings were consistent even when the only non‐native present was Perca fluviatilis. Temperature appeared to limit the distribution of non‐native species, such that the presence of deep thermal refugia is currently facilitating S. alpinus co‐existence with non‐natives in associated lakes. Diet analysis identified P. fluviatilis as potential predators and competitors. This study provides strong evidence that non‐native species are a key driver of low S. alpinus abundance in Irish lakes. Temperature increases associated with climate change are identified as a secondary concern, as they could erode S. alpinus' thermal niche and lead to their extirpation. The lower thermal buffering capacity of shallow lakes identifies these as higher risk systems. Salvelinus alpinus conservation in Ireland should focus on preventing future illegal non‐native species introductions because unlike other stressors (e.g., eutrophication etc.), species introductions are rarely reversible.
Combining natural capital accounting tools and ecosystem restoration approaches builds on existing frameworks to track changes in ecosystem stocks and flows of services and benefits as a result of ...restoration. This approach highlights policy‐relevant benefits that arise due to restoration efforts and helps to maximize opportunities for return on investment. Aligning the System of Environmental Economic Accounting–Ecosystem Accounting (SEEA EA) framework with risk assessment tools, we developed a risk register for peatlands in two contrasting catchments in Ireland, based on available information relating to peatland stocks (extent and condition) and flows (services and benefits), as well as knowledge of pressures. This approach allowed for identification of areas to target peatland restoration, by highlighting the potential to reduce and reverse negative trends in relation to provisioning, regulating, and cultural services, flows relating to non‐use values, as well as abiotic flows. We also highlighted ways to reduce and reverse the effects of historical and ongoing pressures through restoration measures, aligning our approach with that outlined in the SER International Principles and Standards for the Practice of Ecological Restoration. Building on the synergies between the SEEA EA and the SER Standards is highlighted as a means to develop transdisciplinary collaboration, to assist in setting and achieving targets set out under the UN Decade on Ecosystem Restoration as well as integrating regional policy targets set under the EU Biodiversity Strategy for 2030, and the related EU Habitats and EU Water Framework Directives.
The degradation of freshwater resources and loss of freshwater biodiversity by anthropogenic activities, including agriculture, are of major global concern. Together with diffuse pollutants, point ...sources, such as where cattle have direct access to riparian margins and watercourses, can potentially present significant environmental challenges. These can include impacts on stream morphology, increased sedimentation, nutrient additions, microbial contamination, and impacts on aquatic biota. Mitigation measures aimed at reducing these frequently include reducing the amount of time cattle spend in riparian margins and watercourses. This is often accomplished through the provision of an alternative water supply and grazing management, or even cattle exclusion measures. Although a number of studies refer to potential negative impacts, there has been little attempt to review previous research on this topic. The key aim of this paper is to collate and review these disparate studies, as well as those relating to the effectiveness of mitigation measures. Although it is difficult to draw generalizations from studies due to the inherent variability between and within catchments, evidence pertaining to impacts in relation to sedimentation, pathogens, and riparian margin vegetation were strong. Conclusions in relation to impacts on stream morphology and nutrient parameters were less clear, whereas studies on responses of macroinvertebrate communities were particularly variable, with differences due to cattle access difficult to separate from catchment scale effects. A greater understanding of the impact of cattle access on watercourses under varying conditions will help inform policymakers on the cost effectiveness of existing management criteria and will help in revising existing measures.
Many aquatic species of conservation concern exist at low densities and are inherently difficult to detect or monitor using conventional methods. However, the introduction of environmental (e)DNA has ...recently transformed our ability to detect these species and enables effective deployment of limited conservation resources. Identifying areas for breeding, as well as the ecological distribution of species, is vital to the survival or recovery of a conservation species (i.e., areas of critical habitat). In many species, spawning events are associated with a higher relative abundance of DNA released within an aquatic system (i.e., gametes, skin cells etc.), making this the ideal time to monitor these species using eDNA techniques. This study aims to examine whether a “snapshot” eDNA sampling approach (i.e., samples taken at fixed points in chronological time) could reveal areas of critical habitat including spawning sites for our target species Petromyzon marinus. We utilized a species‐specific qPCR assay to monitor spatial and temporal patterns in eDNA concentration within two river catchments in Ireland over three consecutive years. We found that eDNA concentration increased at the onset of observed spawning activity and patterns of concentration increased from downstream to upstream over time, suggesting dispersal into the higher reaches as the spawning season progressed. We found P. marinus to be present upstream of several potential barriers to migration, sometimes in significant numbers. Our results also show that the addition of a lamprey‐specific fish pass at an “impassable” weir, although assisting in ascent, did not have any significant impact on eDNA concentration upstream after the pass had been installed. eDNA concentration was also found to be significantly correlated with both the number of fish and the number of nests encountered. The application of snapshot sampling techniques for species monitoring therefore has substantial potential for the management of low‐density species in fast‐moving aquatic systems.
Many aquatic species of conservation concern exist at low densities and are inherently difficult to detect or monitor using conventional methods. Here, we used a “snapshot” eDNA sampling approach to reveal relative patterns in eDNA concentration within a river catchment. Using this approach, we successfully outlined fine‐scale spatio‐temporal patterns of movement as well as uncovering the location of critical habitat and spawning sites for our target species Petromyzon marinus.
Riparian vegetation supports high biodiversity providing many services and is, therefore, an important landscape element. Riparian ecosystems are subject to numerous pressures leading to population ...decline and genetic erosion of riparian plants. This may have cascading effects at various ecosystem levels, including decreasing ecosystem services, so identifying the current status of genetic diversity of riparian tree species is vital to improve the effectiveness of restoration efforts.
We aimed to elicit expert views on the status and importance of genetic diversity of tree species, and conservation needs across European riparian ecosystems. Sharing of such information among researchers, managers and policymakers has the potential to enhance ecological restoration and management of riparian ecosystems.
We identified experts in riparian genetic resources conservation and management across Europe. These included stakeholders with different perspectives, ranging from researchers to practitioners. We designed a set of questionnaires where our identified experts were asked to answer questions related to the status and conservation of genetic diversity of riparian tree species in their respective countries. Specifically, we asked about societal awareness, legislative tools, good practices and conservation or restoration projects accounting for intraspecific genetic diversity and differentiation of tree species in riparian ecosystems. Questionnaire responses were analysed and discussed in light of the scientific literature to define needs and priorities related to the management and conservation of genetic diversity of riparian tree species.
The experts recognized that a combination of in situ and ex situ measures and/or integrative conservation of riparian ecosystems is the most appropriate option for conserving the genetic diversity of riparian tree species. Simultaneous application of conservation measures at the level of priority species, identified by experts, and protection of riparian areas are required.
Synthesis and applications. This study revealed the importance of recognizing the ecological processes that shape the genetic diversity of riparian tree species in hydrographic networks (dendritic spatial configuration, specific patterns of gene flow among riparian populations, fragmentation of river by dams) but also the need to overcome socio‐economic barriers, such as lack of policy priority, deficiency in funding and weak legislation framework.
This study revealed the importance of recognizing the ecological processes that shape the genetic diversity of riparian tree species in hydrographic networks (dendritic spatial configuration, specific patterns of gene flow among riparian populations, fragmentation of river by dams) but also the need to overcome socio‐economic barriers, such as lack of policy priority, deficiency in funding and weak legislation framework.
Pollan, Coregonus autumnalis pollan Thompson, requires an appropriate standardised sampling protocol for conservation assessments. The suitability of hydroacoustics with gillnetting was evaluated, ...and the effects of sampling design, effort and statistical analysis on the repeatability of results were tested. Summer hydroacoustic surveys appear appropriate as pollan were not abundant in acoustically unsampled areas. However, pollan density estimates were significantly affected by the gillnet sampling design used to ground‐truth the acoustic data. Density estimates from the >12‐ m layer were more robust to gillnet design than estimates from the 3‐ to 12‐ m layer. Estimates from different transect designs yielded some statistically significant results. Comparison of transects common to both transect designs suggests that observed differences reflect temporal changes rather than transect design effects. The reduction in the systematic parallel transect effort by half significantly affected target strength distributions but not pollan density estimates. Density estimates were affected by statistical analysis method where pollan density was highest, with geostatistical analysis providing higher estimates than the arithmetic mean. Hydroacoustic assessments may provide a reliable index of pollan abundance over time and between lakes but future research should investigate the effects of temporal and abiotic factors.
Aim: To construct a classification system for Irish aquatic river vegetation that is directly comparable to European aquatic vegetation classification units. Location: A total of 2,415 river ...vegetation plots with a wide geographic distribution across both the Republic and Northern Ireland. Methods: The plots were recorded from a range of river types from upland streams to wadeable lowland rivers. A total of 1,613 plots were classified using supervised K-means clustering through the programme JUICE. The Phi co-efficient for presence/absence data was used to measure fidelity of the vegetation communities. Results: The vegetation communities could be initially sub-divided in to four main categories: (1) bryophyte-dominated aquatic vegetation, (2) bryophyte-dominated marginal vegetation, (3) vascular plant-dominated aquatic vegetation and (4) vascular plant-dominated marginal/emergent vegetation. Within these four categories the vegetation was classified into seven classes, 18 alliances and 30 associations. Descriptions are given for each including variants and sub-associations if found at association level. Conclusions: There is a rich diversity of bryophyte communities within Irish rivers and they are an integral part of the river network, whereas there was less diversity among vascular plant communities. The distinction between some communities was not as sharp as expected for a variety of reasons discussed in this paper, nevertheless, a working classification system was constructed.
Small, 1st and 2nd-order, headwater streams and ponds play essential roles in providing natural flood control, trapping sediments and contaminants, retaining nutrients, and maintaining biological ...diversity, which extend into downstream reaches, lakes and estuaries. However, the large geographic extent and high connectivity of these small water bodies with the surrounding terrestrial ecosystem makes them particularly vulnerable to growing land-use pressures and environmental change. The greatest pressure on the physical processes in these waters has been their extension and modification for agricultural and forestry drainage, resulting in highly modified discharge and temperature regimes that have implications for flood and drought control further downstream. The extensive length of the small stream network exposes rivers to a wide range of inputs, including nutrients, pesticides, heavy metals, sediment and emerging contaminants. Small water bodies have also been affected by invasions of non-native species, which along with the physical and chemical pressures, have affected most groups of organisms with consequent implications for the wider biodiversity within the catchment. Reducing the impacts and restoring the natural ecosystem function of these water bodies requires a three-tiered approach based on: restoration of channel hydromorphological dynamics; restoration and management of the riparian zone; and management of activities in the wider catchment that have both point-source and diffuse impacts. Such activities are expensive and so emphasis must be placed on integrated programmes that provide multiple benefits. Practical options need to be promoted through legislative regulation, financial incentives, markets for resource services and voluntary codes and actions.
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•Small Water Bodies (SWB) provide a suite of vital ecosystem services.•Hydromorphology of SWBs makes them highly vulnerable to anthropogenic pressures.•Land-use and environmental changes are disrupting the ecosystem functions of SWBs.•3-tier restoration is needed: channel, riparian and wider catchment management.•Success will require government prioritization, expert advice, and stakeholder buy-in.
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