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The ubiquitous nature of microplastics in aquatic ecosystems may have serious implications for aquatic biota. While microplastic research in freshwater ecosystems is increasing, very few studies have assessed the physical presence of microplastics among top predators. The Eurasian otter (Lutra lutra), a top predator of aquatic ecosystems, is one of the most widely distributed otter species and has a broad habitat niche. The opportunistic collection of otter spraints (i.e., feces) presents a valuable opportunity to assess pollutants of freshwater ecosystems through noninvasive means. Here, we assessed the prevalence, abundance, and concentration of microplastics (100 μm to 5 mm), as well as dietary remains, in 53 spraint samples collected over eight river catchments spanning three regions of Ireland. We found microplastics present in 57% of spraints at an abundance of 1.2 ± 0.1 microplastics (MPs)/spraint (mean ± SE) and a concentration of 3.8 ± 0.6 MPs/g (dry weight). Fibers were the dominant particle type recovered (85%), followed by film (10%). No significant differences in microplastic concentrations were detected between the three regions assessed, or between spraints collected from areas upstream (i.e., "lower" exposure) or downstream ("higher" exposure) of putative microplastic sources, which were defined using spatial vector data. While microplastic concentrations were not explained by spraint condition (i.e., fresh, drying, or dry), spraints collected in autumn had a significantly higher concentration than spring and summer. Furthermore, microplastic abundance or concentration could not be linked to dietary composition based on the items identified. From a trophic perspective, this study showed that the presence of microplastics in the feces of otter is most likely being obtained through its prey (i.e., secondary ingestion). While there may be limitations associated with using spraints as a biomonitoring tool for microplastics in freshwater systems, particularly with respect to otter home range and dietary niche breadth, they could still be employed for a regional assessment of microplastic levels. [ABSTRACT FROM AUTHOR]

Animal populations at northern latitudes may have cyclical dynamics that are degraded by climate change leading to trophic cascade. Hare populations at more southerly latitudes are characterized by dramatic declines in abundance associated with agricultural intensification. We focus on the impact of historical climatic and agricultural change on a mid‐latitude population of mountain hares, Lepus timidus hibernicus. Using game bag records from multiple sites throughout Ireland, the hare population index exhibited a distinct regime shift. Contrary to expectations, there was a dynamical structure typical of northern latitude hare populations from 1853 to 1908, during which numbers were stable but cyclic with a periodicity of 8 years. This regime was replaced by dynamics more typical of southern latitude hare populations from 1909 to 1970, in which cycles were lost and numbers declined dramatically. Destabilization of the autumn North Atlantic Oscillation (NAO) led to the collapse of similar cycles in the hare population, coincident with the onset of agricultural intensification (a shift from small‐to‐large farms) in the first half of the 20th century. Similar, but more recent regime shifts have been observed in Arctic ecosystems and attributed to anthropogenic climate change. The present study suggests such shifts may have occurred at lower latitudes more than a century ago during the very early 20th century. It seems likely that similar tipping points in the population collapse of other farmland species may have occurred similarly early but went undocumented. As northern systems are increasingly impacted by climate change and probable expansion of agriculture, the interaction of these processes is likely to disrupt the pulsed flow of resources from cyclic populations impacting ecosystem function. [ABSTRACT FROM AUTHOR]

The global amphibian crisis is driven by a range of stressors including disease, habitat loss, and environmental contamination. The role of climate change remains poorly studied and is likely to influence environmental suitability, ranges, reproduction, and phenology. This study aimed to characterize the bioclimatic‐habitat niche space of the Natterjack toad (Epidalea calamita) throughout its European range and to assess the impact of climate on the toad's environmental suitability and breeding behavior in Ireland, where declines in recent decades have resulted in it being regionally Red‐Listed as Endangered. To address these questions, we first identified which climate variables best predict the current bioclimatic niche, fecundity (number of eggs deposit), and phenology. We then used future climate projections for two time periods (2041–2060 and 2061–2080) and two greenhouse gas emission scenarios (RCP 4.5 and RCP 8.5) to predict how the species range, fecundity, and phenology would change. The European range of the species was found to be limited by winter temperatures while its bioclimatic niche varied markedly throughout its range. Species distribution models suggested projected climate change will increase environmental suitability for the species throughout its range, including Ireland, but most notably in Scandinavia and the Baltic. Fecundity in Ireland was greatest during the cool temperatures of spring and after wet winters associated with ephemeral breeding pool availability. Warm, dry summers in the preceding year influenced fecundity the following spring indicative of carryover effects. Initiation of spawning was driven by spring temperatures, not rainfall. Projections suggested future climate change may increase fecundity in Ireland while spawning may commence earlier throughout the 21st century especially under a high greenhouse gas emission scenario (RCP 8.5). Despite recent range contraction and population declines due to habitat deterioration, the Natterjack toad, if subject to a suitable species conservation strategy, has the potential to be a climate change winner, notwithstanding unpredictable habitat and land‐use change, sea‐level rise inducing coastal erosion, changes in invertebrate prey abundance, and disease. [ABSTRACT FROM AUTHOR]

According to the International Union for Conservation of Nature Red List, 41% of the world's amphibian species are threatened with extinction, making them more threatened than any other vertebrate group nowadays. Given the global amphibian crisis, comprehensive understanding of demographics and population trends of declining and threatened species is essential for effective management and conservation strategies. Counting egg spawns is widely used to assess population abundance in pond breeding anurans. However, it is unknown how such counts translate into robust population size estimations. We monitored the breeding activity of the Natterjack toad (Epidalea calamita), combining egg string counts and individual photo‐identification with Capture‐Mark‐Recapture population size and operational sex ratio estimation. Male Natterjack toads were identified by the pattern of natural markings with repeated ID of the same individual confirmed for 10% of the samples using genetic fingerprinting. We identified 647 unique individuals within a closed study population at Caherdaniel, Co Kerry. Population estimates derived from egg string counts estimated a breeding population of 368 females (95% CI 353–384) and Capture‐Mark‐Recapture estimated a breeding population of 1698 males (95% CI 1000–2397). The female:male sex ratio was conservatively estimated at 1:5 (95% CI 1:3–1:6) where 62% ± 6% of females were assumed to spawn. These substantially departed from any priori assumption of 1:1 which could have underestimated the breeding population by up to 72%. Where amphibian absolute population size estimation is necessary, methods should include empirical survey data on operational sex ratios and not rely on assumptions or those derived from the literature which may be highly population and/or context‐dependent. [ABSTRACT FROM AUTHOR]

Farmland ponds are a highly threatened freshwater habitat which has undergone dramatic losses during the last 200 years due to land drainage schemes and agricultural intensification. Agri‐environment schemes (AES) incentivize farmers to adopt farming methods to benefit biodiversity, yet there are a paucity of data evaluating the success of artificially created AES ponds as analogues of natural ponds in an attempt to recreate lost environments.We examined variation in environmental parameters and aquatic and terrestrial invertebrate communities between 38 natural ponds and 91 artificial ponds that were created in south‐west Ireland (n = 129).Artificial ponds in agricultural grassland did not replicate natural ponds in adjacent semi‐natural habitats differing significantly in size, pH, conductivity, productivity (indicated by submerged and emergent plant cover including algae) and surrounding vegetation structure that is, sward height. These differences significantly influenced aquatic and terrestrial invertebrate community structure with a suite of indicator taxa in both natural and artificial ponds.The conservation value of artificial ponds in agricultural grasslands should not be underestimated as they had 43% higher aquatic species richness and 33% higher aquatic species abundance than natural ponds in adjacent semi‐natural habitats.Synthesis and applications. We demonstrate that artificial agri‐environment scheme ponds created in agricultural grasslands, whilst not direct analogues of natural ponds in adjacent semi‐natural habitats, do fulfil a role in preserving high local biodiversity albeit representing a different community of species. Creation of ponds in farmland as well as in adjacent natural habitats could provide a wider range of environmental conditions and richer associated macroinvertebrate communities, increasing landscape connectivity and further enhancing regional biodiversity. [ABSTRACT FROM AUTHOR]

Empirical studies of the spatiotemporal dynamics of populations are required to better understand natural fluctuations in abundance and reproductive success, and to better target conservation and monitoring programmes. In particular, spatial synchrony in amphibian populations remains little studied. We used data from a comprehensive three year study of natterjack toad Bufo calamita populations breeding at 36 ponds to assess whether there was spatial synchrony in the toad breeding activity (start and length of breeding season, total number of egg strings) and reproductive success (premetamorphic survival and production of metamorphs). We defined a novel approach to assess the importance of short-term synchrony at both local and regional scales. The approach employs similarity indices and quantifies the interaction between the temporal and spatial components of populations using mixed effects models. There was no synchrony in the toad breeding activity and reproductive success at the local scale, suggesting that populations function as individual clusters independent of each other. Regional synchrony was apparent in the commencement and duration of the breeding season and in the number of egg strings laid (indicative of female population size). Regional synchrony in both rainfall and temperature are likely to explain the patterns observed (e.g. Moran effect). There was no evidence supporting regional synchrony in reproductive success, most likely due to spatial variability in the environmental conditions at the breeding ponds, and to differences in local population fitness (e.g. fecundity). The small scale asynchronous dynamics and regional synchronous dynamics in the number of breeding females indicate that it is best to monitor several populations within a subset of regions. Importantly, variations in the toad breeding activity and reproductive success are not synchronous, and it is thus important to consider them both when assessing the conservation status of pond-breeding amphibians. [ABSTRACT FROM AUTHOR]

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