Forage and Range Evaluation

Schwartz, Chuck; Hobbs, Niels-Viggo

doi:10.1201/9781351070218-2

Cited by 3 publications

(2 citation statements)

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“…Across Table 6. Estimated minimum (Eqn 3) and maximum (Eqn 4) energy intake by roe deer for each age class and season (without fawns), and significances among the different groups with P = 0.05. all sites, the CP content decreases continuously from 24.5% DM in spring to 19.7% DM in winter (Table 4), thus reflecting plant growth with its cell deposits over the course of the vegetation phases (Schwartz and Hobbs 1985). This annual pattern in the CP concentrations in the ingested diet has already been described in many other studies (Drodz and Osiecki 1973;Serrano Ferron et al 2012;König et al 2020) and is consistent with their results.…”

Section: Discussionsupporting

confidence: 89%

Energy intake and nutritional balance of roe deer (Capreolus capreolus) in special Bavarian landscapes in southern Germany

2023

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Context Irrespective of the fact that the European roe deer (Capreolus capreolus) occurs from the Mediterranean to north of the Arctic Circle and is one of the most abundant and widespread species, roe deer are fed in winter in Germany and Austria. Hunters justify the supplementary feeding with the argument that roe deer do not find sufficient high-quality food in our landscape and they would have to starve in winter. Aims Our aim was to measure the quality and energy content of the browsed roe deer diet (in terms of metabolisable energy, ME) and the daily energy intake by roe deer. Methodology Between 2017 and 2019, rumenreticula of 629 roe deer were collected from five extreme habitats in Bavaria. Samples were examined by standard methods of dietary analysis, such as in vitro ruminal fermentation, crude nutrient analysis and the analysis of neutral/acid detergent fibre and acid detergent lignin. In addition, data on body condition and age were collected for each roe deer. Key results The diet consumed by roe deer has an energy density between 5.1 MJ/kg dry matter (DM) and 6.1 MJ/kg DM on average. Crude fibre contents in the diet varied between 20% and 38% DM. Roe deer compensate for lower energy densities in vegetation by consuming more diet. Across all habitats, adult consumed an annual mean of between 10.6 and 12.9 MJ ME/day. Conclusions Roe deer find sufficient high-energy food in all landscape types. They consume and can utilise raw fibre to the same extent as do red deer or mouflon. Differences in energy density among habitats result from carbohydrate content and are compensated for by more food intake. Energy deficits in roe deer could not be detected in any habitat at any time. Implications Roe deer do not need supplementary feeding in any habitat. Supplementary feeding leads to browsing damage because of the lack of raw fibre in the feed.

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Section: Discussionsupporting

confidence: 89%

Energy intake and nutritional balance of roe deer (Capreolus capreolus) in special Bavarian landscapes in southern Germany

2023

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“…This is the problem confronted by herbivores that encounter potential foods at rates that are orders of magnitude higher than encounter rates with prey by predators (Senft et al, 1987). However, when plant tissue is “captured,” it contains nutrients diluted by indigestible or slowly digested fiber and other nonnutritious materials (reviewed by Mattson, 1980; Schwartz & Hobbs, 1985; White, 1993). Plants are highly variable in their nutritional value, in contrast to animal prey, containing nutrient concentrations that differ by several fold depending on plant species, plant age, tissue type, and growth form (reviewed by Mattson, 1980; Schwartz & Hobbs, 1985).…”

Section: Conceptual Frameworkmentioning

confidence: 99%

A general, resource‐based explanation for density dependence in populations of large herbivores

Hobbs

2024

Ecological Monographs

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The discipline of ecology seeks to understand how ecosystems, communities, and populations are regulated. A ubiquitous mechanism of population regulation of consumers is that capturing energy and nutrients in sufficient quantities for survival and reproduction becomes more difficult as population density increases. Extensive evidence has revealed that populations of large herbivores are often regulated by density dependence, defined as the reduction in the per‐capita population growth rate that occurs as populations grow large. Diminished body mass of individuals has been repeatedly observed in high‐density populations, implicating compromised nutrition as the primary cause of density dependence. However, there is no general explanation for why these nutritional deficiencies occur. Recent work demonstrated that reduced food intake rates resulting from the functional response of herbivores to depleted plant biomass does not provide a sensible explanation for density dependence because rates of food intake of herbivores are often insensitive to changes in plant biomass. A new model of feedbacks from plant biomass to herbivores shows how reduced nutrition of herbivores can result from increased dilution of nutrients in the plant tissue they consume as populations grow, even when their rate of consumption of plants remains constant. The model contains parameters that can be scaled to body mass, allowing unusually general predictions. The model shows that convex, concave, and linear relationships between the per‐capita growth rate and population density can arise from the effects of depletion of plant biomass by herbivore foraging. The model is the first to explicitly include spatial variance in the nutritional quality of plants as a general driver of herbivore population dynamics. I show how regulation of herbivore abundance by plant nutrients can occur, even when a large fraction of the consumable plant biomass remains uneaten, providing a simple, mechanistic explanation for bottom‐up control of population dynamics of primary consumers in a “green world.”

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Habitat Use and Diet of Desert Bighorn Sheep (Ovis Canadensis Mexicana) and Endemic Mule Deer (Odocoileus Hemionus Nelsonii) on Tiburón Island, Mexico

O‘Farrill

Medellín

Matter

et al. 2019

The Southwestern Naturalist

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Forage and Range Evaluation

Cited by 3 publications

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Energy intake and nutritional balance of roe deer (Capreolus capreolus) in special Bavarian landscapes in southern Germany

Energy intake and nutritional balance of roe deer (Capreolus capreolus) in special Bavarian landscapes in southern Germany

A general, resource‐based explanation for density dependence in populations of large herbivores

Habitat Use and Diet of Desert Bighorn Sheep (Ovis Canadensis Mexicana) and Endemic Mule Deer (Odocoileus Hemionus Nelsonii) on Tiburón Island, Mexico

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