Data from: Dietary complexity and hidden costs of prey switching in a generalist top predator ...
Summary 1. Variation in predator diet is a critical aspect of food web stability, health, and population dynamics of predator / prey communities. Quantifying diet, particularly among cryptic species, is extremely challenging however, and differentiation between demographic subsets of populations is...
| Main Authors: | , , , , |
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| Format: | Dataset |
| Language: | English |
| Published: |
Dryad
2020
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.5dv41ns3k https://datadryad.org/stash/dataset/doi:10.5061/dryad.5dv41ns3k |
| Summary: | Summary 1. Variation in predator diet is a critical aspect of food web stability, health, and population dynamics of predator / prey communities. Quantifying diet, particularly among cryptic species, is extremely challenging however, and differentiation between demographic subsets of populations is often overlooked. 2. We used prey remains and data taken post mortem from otter Lutra lutra to determine the extent to which dietary variation in a top predator was associated with biotic, spatial and temporal factors. 3. Biotic data (e.g. sex, weight, length) and stomach contents were taken from 610 otters found dead across England and Wales between 1994-2010. Prey remains were identified to species where possible, using published keys and reference materials. Multi-model inference followed by model prediction were applied to test for and visualise the nature of associations. 4. Evidence for widespread decline in the consumption of eels (Anguilla anguilla) reflected known eel population declines. An association ... : Otters found dead were collected across England and Wales between 1994 and 2010, as part of a national scheme coordinated by Cardiff University. The entire stomach and intestine were taken during post mortem examination of 610 otters, and frozen at -20°C. The year, month and location where each otter was found were recorded. Distance to the coast via the nearest river (river distance) was measured using ArcMap GIS (V.9.2, ESRI 2006). Where otters were found more than 1000 m from a river, river distance was omitted. Each otter was assigned to one of eight regions, based on aggregations of adjacent river catchments. Each otter was examined in detail at post mortem; sex, age class (adult, sub-adult, juvenile), reproductive status (females only), weight (kg, to the nearest 10 grams), length (mm, to the nearest 5 mm, measured nose to anus and anus to tail tip) and cause of death were determined. Morphometric and reproductive data were used to assign age class, such that males below 3 kg and females below 2.1 kg ... |
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