-The diet composition of the European otter Lutra lutra was assessed using spraint analysis in the Hampshire Avon, a lowland chalk stream in Southern England, over an 18-month period. Small cyprinid fishes were the main prey item taken in all seasons, with bullhead Cottus gobio and stone loach Barbatula barbatula also important; there were relatively few larger fishes of interest to fisheries found. There were significant seasonal differences in diet composition by season, with signal crayfish Pacifastacus leniusculus only being prominent prey items in warmer months and amphibians in winter, revealing that non-fish resources were seasonally important dietary components. Reconstructed body lengths of prey revealed the only species present in diet >350 mm was pike Esox lucius. These dietary data thus provide important information for informing conservation conflicts between otters and fishery interests.Keywords: otter spraint / Barbus barbus / angling / conservation conflict Résumé -Importance des petits poissons et des écrevisses envahissantes dans le régime alimentaire de la loutre Lutra lutra dans une rivière calcaire anglaise. La composition du régime de la loutre Lutra lutra a été évaluée à l'aide d'une analyse des épreintes dans le Hampshire Avon, un cours d'eau calcaire de plaine dans le sud de l'Angleterre, sur une période de 18 mois. Les petits poissons cyprinidés ont été les principales espèces de proies prises en toutes saisons, avec le chabot Cottus gobio et la loche franche Barbatula barbatula également fréquents ; il y avait relativement peu de plus grands poissons d'intérêt pour les pêcheries. Il y avait des différences saisonnières significatives dans la composition de régime, avec l'écrevisse signal Pacifastacus leniusculus n'étant qu'une proie fréquente pendant les mois les plus chauds et les amphibiens en hiver, révélant que les ressources autres que le poisson étaient des composants alimentaires saisonnièrement importants. Des longueurs de proies reconstituées ont révélé que la seule espèce de taille >350 mm présente dans le régime était le brochet Esox lucius. Ces données alimentaires fournissent donc des connaissances importantes pour informer les conflits de conservation entre les loutres et les intérêts de pêche.
Grassed waterways are used to mitigate the offsite transport of sediment generated by soil erosion. This study used a novel trait-based ranking approach as a method to screen potential candidate grass monocultures and mixes based on their theoretical performance in reducing (a) detachment via rainsplash, (b) detachment via scouring due to concentrated flow and (c) sediment transport and deposition processes.Selected grass species were grown under simulated UK summer and autumn establishment conditions under three different replicated rainfall scenarios: drought, normal rainfall and excess rainfall. The grass species used were the novel hybrid species Festulolium cv Prior (Fest_1) and Festulolium Bx511 (Fest_2) and a conventional mixture of Lolium perenne and Festuca rubra (Conv). Monocultures and mixtures of these species were studied. Plant traits pertinent to control of soil erosion by water were measured. Aboveground traits included plant height, percentage ground cover, aboveground biomass, stem diameter, stem area density and number of tillers. Belowground traits included total root length, root total surface area, belowground biomass, root diameter and % fine roots ≤0.25 mm. For summer conditions, the species treatments that had the highest overall soil erosion mitigation potential were Conv, Fest_1 + 2 + Conv and Fest_2. For autumn conditions, the best treatments were Fest_1 + 2, Fest_1 + 2 + Conv and Conv. The Fest 1 + 2 + Conv had more desirable traits for erosion control than mono Festulolium treatments for the autumn conditions. The conventional mixture had more desirable traits for erosion control than mono Festulolium treatments in both climate scenarios. The results indicate that the trait-based ranking approach utilized in this study can be used to inform rapid screening of candidate grass species for soil erosion control. Highlights• How to select the most suitable grass species for soil erosion control under changing climate conditions? • A novel scoring system based on plant traits associated with soil erosion mitigation was developed.• Fest_1 + 2 and Conv treatments expressed traits strongly associated with maximum soil erosion mitigation.
<p>Grassed waterways reduce water runoff, prevent scouring and encourage sediment deposition from erosion prone land. The aim of this study was to assess the efficacy of conventional and novel grass species (as monocultures and mixtures) to control erosion, at an early establishment stage (6 weeks), within grassed waterways. The experimental treatments included bare soil (B), a conventional mix of Lolium perenne and Festuca rubra (C), Festulolium cv prior (F1), Festulolium cv prior and Festulolium bx511 (F1+F2), and all grass species combined (F1+F2+C). F1 is adapted to flooded conditions, whilst F2 is adapted to drought conditions. With climate change in the UK likely to result in drier summers and wetter winters these Festulolium species will be adapted to future climatic conditions. However, little is known about their efficacy within grassed waterways. The grasses were established in 1.2 x 1 x 0.5m macrocosms in a sandy clay loam soil during June-Aug, 2019. A sub sample of each experimental treatment was taken (0.3 x 0.1 x 0.1m) from the macrocosms within a stainless steel box. Tests were replicated in quadruplicate.<br>The following above ground trait (Stem area density) and the following below ground traits (Total root length of fine roots <0.25mm, root diameter and root surface area) were determined for each experimental replicate. Prior to testing, the grass was cut to circa 3.0 cm height to represent a mowed grass sward before being placed into a fully instrumented hydraulic flume. The hydraulic flume simulated a concentrated flow event and treatment performance was assessed in terms of turbidity, sediment concentration, soil loss and flow velocity.<br>The effects of roots+shoots and of roots only on performance indicators were determined to quantify the relative contribution of above ground vs below ground traits in controlling erosion. One set of replicates was tested only with roots whilst another set of replicates was tested with roots+shoots and then with roots only. This was done to isolate the effect of below ground and above ground traits.<br>All replicates were subjected to a concentrated flow event with increasing incremental flow velocities from 0.2-0.6l s-1 for bare soil, 0.2-0.8l s-1 for roots+shoots treatments and 0.2-1.4l s-1 for roots only treatments. Each flow rate velocity was run for 60 seconds. For each flow rate, duplicate water samples were taken downslope of the treatment and water depth was measured, upstream of the treatment, in the centre of the treatment and downstream of the treatment. &#160;The water samples were used to determine sediment concentrations. The water depth measurements were used to determine runoff velocity. Furthermore, a turbidity meter continuously measured turbidity during the concentrated flow event. Soil detachment and transport rates were significantly reduced for all experimental treatments as compared to the bare soil (p<0.05). Final treatment efficacy will be assessed based on a ranking of the key performance indicators. The knowledge gained from this research can be used and applied to other grassed soil erosion mitigation features such as in field and riparian buffer strips, swales as well as grassed waterways.</p><p>&#160;</p>
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