Two models for assessing the prey mass of European ungulates from wolf scats

Abstract

2003. Two models for assessing the prey mass of European ungulates from wolf scats. Acta Theriologica 48: 527-537.Among the prey of wolf Canis lupus Linnaeus, 1758, in many European regions, roe deer Capreolus capreolus, red deer Cervus elaphus and wild boar Sus scrofa are of primary significance. Up to now, these species were not represented in models which allow an estimation of the consumed biomass on the basis of wolf scats. To develop such formulae for roe deer, red deer and wild boar, we fed these species to 5 captive adult wolves of European origin. In 10 feeding trials, the wolves were fed 10 prey, whose body mass ranged from 15.3 to 118.5 kg. We related the body mass of the prey in accordance with Weaver (1993) to one collectable scat (Model l: y = 0.00554 + 0.00457x) and, as it is difficult to define one unit scat, we alternatively related it to one meter length of scats (Model 2: y = 0.141 + 0.0487x). The Model 1 equation differed from both of Weaver's (1993) regressions, which he had calculated on the basis of his own feeding trials and on the basis of the summarised data of Floyd et al. (1978), Traves (1983) andWeaver (1993). Applying an equation gained through the European ungulates resulted in lower estimates of prey mass. Model 1 and Model 2 estimates were comparable in size.

Prey selection and dietary response by wolves in a high-density multi-species ungulate community

“…The selection was considered not significant if confidence intervals included 1 (Manly et al 2002). Furthermore, confidence intervals (α=0.01) were calculated using the Bonferroni correction and used to test differences in biomass models by Weaver (1993), Ruehe et al (2003) and Floyd et al (1978). Statistical analyses were performed using SPSS 13.0 software package.…”

Data for estimating eaten prey masses from Eurasian lynxLynx Lynx scats in Central and East Europe

“…Apart from 3 yearlings (the mouflon, the fallow deer and a roe deer) all ruminants were > 1 year old. The trial design followed Floyd et al (1978), Traves (1983), Weaver (1993) and Ruehe et al (2003). In each of the nine feeding trials one whole animal weighing from 4.7 to 25.1 kg fm was offered, except for the mice, which were fed to the lynx in one trial (Table 1; we weighed the bodies and their uneaten remnants of £ 5 and > 5 kg fm using scales with a precision of 0.001 and 0.1 kg, respectively).…”

“…Scats were collected twice a day. All of them were collectable (unlike wolf scats cf Floyd et al 1978, Traves 1983, Weaver 1993, Ruehe et al 2003 and each scat could easily be distinguished from another. Each scat was carefully cleaned from attached non-scat particles, weighed to a precision of 0.1 g (fm), sealed in consecutively numbered air-tight plastic bags and stored at -18°C.…”

“…Analyses of lynx scats may provide information not only about the prey species but also about the masses of consumed prey types. However, coefficients of digestibility (Lehmann 1890) or biomass models (Floyd et al 1978, Traves 1983, Weaver 1993, Ruehe et al 2003) based on lynx scats have not been developed to date. In former studies on lynx diets (Jêdrzejewski et al 1993) conversion factors (CF) from dry matter (dm) masses of scat fractions to eaten fresh matter (fm) of prey masses developed for red foxes Vulpes vulpes (Goszczyñski 1974) had been used.…”

Interactions of wolves, mountain caribou and an increased moose-hunting quota --- Primary-prey management as an approach to caribou recovery.

“…This bias has arguably been resolved by converting the results of scat analysis from frequency occurrence to biomass consumed, which is more ecologically relevant (Klare et al 2011). The conversion is possible by using linear relationships calculated from feeding trials with captive wolves (Floyd et al 1978, Ruehe et al 2003. Another concern with scat analysis is discerning among scats of canid species.…”