Environmental DNA concentrations vary greatly across productive and degradative conditions, with implications for the precision of population estimates

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: July 29, 2024

Abstract Population size is an important metric to inform the conservation and management of species. For aquatic species, environmental DNA (eDNA) concentration has been suggested for non-invasively estimating population size. However, many biotic abiotic factors simultaneously influence production degradation eDNA which can alter relationship between concentration. We investigated temperature, salinity, ranavirus infection on concentrations using tadpole mesocosms. Using linear regression models, we tested each experimental treatment at three time points before during epidemics. Prior infection, elevated temperatures lowered concentrations, indicating that was driving force influencing concentrations. During early epidemics, no treatments strongly influenced in late productive forces dominated as intensity dead organisms increased Finally, only predictor epidemics observed high levels variation samples replicate demonstrate complexities several interacting degradative forces, influences over short spans, examine limitations sizes from with precision semi-natural conditions.

Language: Английский

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Combining genetic non-invasive sampling with spatially explicit capture-recapture models for density estimation of a patchily distributed small mammal

European Journal of Wildlife Research, Journal Year: 2018, Volume and Issue: 64(4)

Published: July 15, 2018

Language: Английский

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Landscape Characteristics Affecting Small Mammal Occurrence in Heterogeneous Olive Grove Agro-Ecosystems

Conservation, Journal Year: 2022, Volume and Issue: 2(1), P. 51 - 67

Published: Jan. 10, 2022

Understanding how small mammals (SM) are associated with environmental characteristics in olive groves is important to identify potential threats agriculture and assess the overall conservation value functioning of agro-ecosystems. Here, we provide first insights on this topic applied traditional northeast (NE) Portugal by assessing landscape attributes that determine SM occurrence, focusing one species concern (Microtus cabrerae Thomas 1906) often perceived as a pest olives lusitanicus Gerbe 1879). Based genetic non-invasive sampling 51 surrounding habitats, identified seven rodent insectivore. Occupancy modelling indicated were generally less detected within than habitats. The vulnerable M. reached mean occupancy (95% CI) 0.77 (0.61–0.87), while stood at 0.37 (0.24–0.52). was more likely occur land mosaics high density agricultural field edges, pastureland patches. Overall, our study suggests complex structure spatial heterogeneity traditionally managed grove agro-ecosystems may favor occurrence species-rich communities, possibly including well-established populations importance, keeping relatively low rates.

Language: Английский

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Comparison of grizzly bear hair‐snag and scat sampling along roads to inform wildlife population monitoring

Wildlife Biology, Journal Year: 2020, Volume and Issue: 2020(3), P. 1 - 12

Published: Sept. 16, 2020

Wildlife managers conduct population inventories to monitor species, particularly those at‐risk. Although costly and time consuming, grid‐based DNA hair‐snag sampling has been the standard protocol for grizzly bear in North America, while opportunistic fecal is more commonly used Europe. Our aim determine if low‐cost, low‐effort scat along roads can replace current standard. We compare two genetic non‐invasive techniques using concurrent within same grid system spatially explicit capture–recapture. found that given our methodology present status of genotyping bears, cannot hair estimate size low‐density areas. Hair identified majority individual with a higher success rate individuals from samples (100%) compared (14%). Using supplement data did not change estimates, but it improve precision. Scat had identifying species (98%) (80%). detected bears cells where showed non‐detection, almost twice number indicating presence. Based on methods projected expenses future implementation, we estimated an approximate 30% cost reduction relative hair. research explores application approaches populations. recommend wildlife continue use as primary method inventories, employing supplemental increase may better indicate presence through greater numbers spatial distribution detections, systematic across entire area interest. findings speak management other regions, contribute ongoing advances monitoring

Language: Английский

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Estimating red deer (Cervus elaphus) population size based on non-invasive genetic sampling

European Journal of Wildlife Research, Journal Year: 2021, Volume and Issue: 67(2)

Published: March 9, 2021

Abstract Some deer species are of conservation concern; others officially managed as a food source or for their trophies, whereas in many regions, regarded overabundant even nuisance causing damages. Regardless local management issues, most cases, reliable data on population sizes and sex ratios lacking. Non-invasive genetic approaches promising tools the estimation size structure. We developed tested non-invasive approach red ( Cervus elaphus ) density based faeces collected from three free-ranging populations south-western Germany. Altogether, we genotyped 2762 faecal samples, representing 1431 different individuals. estimated both sexes separately using two approaches: spatially explicit capture-recapture (SECR) single-session urn model (CAPWIRE). The densities were similar all study areas, ranging between total 3.3 (2.5–4.4) 8.5 (6.4–11.3) deer/km 2 . differed significantly studied (ranging 1:1.1 1:1.7), resulting considerable consequences management. In further research, issues closure approximation effectively sampled area should be addressed. presented can serve valuable tool populations, to our knowledge, it represents only sex-specific density.

Language: Английский

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