Biology subjects

Sutherland, C.

Publications and source records attributed to Sutherland, C..

22 records · Page 2Linked to original sources

bioRxiv2019

Fishing for mammals: landscape-level monitoring of terrestrial and semi-aquatic communities using eDNA from lotic ecosystems

O_LIEnvironmental DNA (eDNA) metabarcoding has revolutionised biomonitoring in both marine and freshwater ecosystems. However, for semi-aquatic and terrestrial animals, the application of this technique remains relatively untested.\nC_LIO_LIWe first assess the efficiency of eDNA metabarcoding in detecting semi-aquatic and terrestrial mammals in natural lotic ecosystems in the UK by comparing sequence data recovered from water and sediment samples to the mammalian communities expected from historical data. Secondly, we evaluate the detection efficiency of eDNA samples compared to multiple conventional non-invasive survey methods (latrine surveys and camera trapping) using occupancy modelling.\nC_LIO_LIeDNA metabarcoding detected a large proportion of the expected mammalian community within each area. Common species in the areas were detected at the majority of sites. Several key species of conservation concern in the UK were detected by eDNA in areas where authenticated records do not currently exist, but potential false positives were also identified for several non-native species.\nC_LIO_LIWater-based eDNA samples provided comparable results to conventional survey methods in per unit of survey effort for three species (water vole, field vole, and red deer) using occupancy models. The comparison between survey effort to reach a detection probability of [≥]0.95 revealed that 3-6 water replicates would be equivalent to 3-5 latrine surveys and 5-30 weeks of single camera deployment, depending on the species.\nC_LIO_LISynthesis and Applications. eDNA metabarcoding represents an extremely promising tool for monitoring mammals, allowing for the detection of multiple species simultaneously, and provides comparable results to widely-used conventional survey methods. eDNA from freshwater systems delivers a terrestrial dividend by detecting both semi-aquatic and terrestrial mammalian communities, and provides a basis for future monitoring at a landscape level over larger spatial and temporal scales (i.e. long-term monitoring at national levels).\nC_LI

ecology↗

bioRxiv2019

Sex-specific population dynamics and demography of capercaillie (Tetrao urogallus L.) in a patchy environment

O_LIModeling the population dynamics of patchily distributed species is a challenge, particularly when inference must be based on incomplete and small data sets such as those from most species of conservation concern. Open population spatial capture-recapture (SCR) models are ideally suited to quantify population trends, but have seen only limited use since their introduction.\nC_LIO_LITo investigate population trend and sex-specific population dynamics, we applied an open SCR model to a capercaillie (Tetrao urogallus) population in Switzerland living in eight distinct forest patches totalling 22 km2 within a region of 908 km2. The population was surveyed using genetic sampling of scat in 2009, 2012 and 2015. We fit an open SCR model with sex-specific detection and population dynamics parameters while accounting for the patchy distribution of habitat and the uncertainty introduced by observing the population in three years only.\nC_LIO_LIBetween 2009 and 2015, a total of 143 males, 112 females and 4 individuals of uncertain sex were detected. The annual per capita recruitment rate was estimated at 0.115 (SE 0.0144) for males and 0.127 (0.0168) for females. The estimated annual survival probability for males was 0.758 (0.0241) and 0.707 (0.0356) for females. The population trajectory implied by these survival and recruitment estimates was a decline of 2% per year; however, the sex specificity of the model revealed a decline in the male population only, with no evidence of decline in the female population. Further, the population decline observed in males was explained by the demography of just two of the eight patches.\nC_LIO_LIUsing a customized open population SCR model, we determined that the endangered capercaillie in our Swiss study area had a stable female population and a declining male population, with the male decline due to population dynamics in a subset of the study area. Our study highlights the flexibility of open population SCR models for assessing population trajectories through time and across space and emphasizes the desirability of estimating sex-stratified population trends especially in species of conservation concern.\nC_LI

ecology↗

bioRxiv2019

Keeping salamanders off the streets: An assessment of one of the first amphibian road tunnels in the United States 30 years after installation

Culverts are often installed under busy roads to help a variety of animals, from small frogs to bears, safely cross roads that bisect their habitats. One of the first roadway culvert systems designed specifically for amphibian use in the United States was installed along Henry Street in Amherst, Massachusetts in 1987 to protect spotted salamanders (Ambystoma maculatum). These salamanders cross Henry Street during their annual migration to their breeding pools. In recent years, anecdotal evidence from volunteers monitoring the site suggested that salamanders were no longer using the tunnels. To evaluate this concern we conducted salamander counts in 2016, 2017, and 2018 to quantify tunnel use. In 2016, only 11% of observed salamanders used the tunnels- a substantial decrease from 68% in 1988, one year after their installation, when the tunnels were last evaluated. Subsequently, we implemented two tunnel modifications in an effort to increase tunnel usage above the established 2016 baseline. Unfortunately, neither retrofit was successful. Previous studies have demonstrated that salamanders prefer minimum tunnel apertures of >0.4 m, so it is likely that the 0.2 m apertures here are inadequate. This may create differential light and humidity inside and outside the tunnels that is recognized by the salamanders. While many studies have evaluated amphibian tunnel use in lab and field settings, ours is one of the first studies to have examined tunnel usage data long after initial installation. These long-term data are critical for evaluating what factors are necessary for maintaining tunnels over decades-long time scales.

ecology↗

bioRxiv2017

Unifying Population and Landscape Ecology with Spatial Capture-recapture

Spatial heterogeneity in the environment induces variation in population demographic rates and dispersal patterns, which result in spatio-temporal variation in density and gene flow. Unfortunately, applying theory to learn about the role of spatial structure on populations has been hindered by the lack of mechanistic spatial models and inability to make precise observations of population structure. Spatial capture-recapture (SCR) represents an individual-based analytic framework for overcoming this fundamental obstacle that has limited the utility of ecological theory. SCR methods make explicit use of spatial encounter information on individuals in order to model density and other spatial aspects of animal population structure, and have been widely adopted in the last decade. We review the historical context and emerging developments in SCR models that enable the integration of explicit ecological hypotheses about landscape connectivity, movement, resource selection, and spatial variation in density, directly with individual encounter history data obtained by new technologies (e.g., camera trapping, non-invasive DNA sampling). We describe ways in which SCR methods stand to revolutionize the study of animal population ecology.

ecology↗