Determinants of Herbivore Carrying Capacity: Plants, Nutrients, and Equus Asinus in Northern Australia

Abstract

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Food limitation and the recovery of sea otters following the 'Exxon Valdez' oil spill

“…Older females were excluded because of possible confounding effects of having a large number of pregnant females among older individuals, and because the effects of a limited food supply were expected to have their greatest impact on younger animals that are generally poorer competitors. Higher starvation-caused mortality in young animals has been suggested for sea otters (Kenyon 1969) and demonstrated for other large mammals (Choquenot 1990, Virgil & Messier 1997. Variation in survival of immature individuals accounts for most of the variation in rates of population increase for marine mammals (Eberhardt & Siniff 1977).…”

“…We relied on both direct and indirect measures of food availability because it is difficult to measure precisely the abundance of the diverse group of sea otter prey, and because prey abundance does not account for factors such as quality of food or the cost to the predator of acquiring its prey. In the absence of other factors that can influence prey abundance, a reduction in the density of food-limited mammalian predators generally leads to an increase in either quantity or quality of food available, and an increase in the condition of the remaining (especially younger) animals (Bobek 1977, Sinclair 1977, Skogland 1983, 1985, Bayliss 1985, Sinclair et al 1985, Fryxell 1987, Freeland & Choquenot 1990, Choquenot 1991, Messier 1994. Therefore, in addition to prey abundance, we examined prey con-sumption rate and condition of young sea otters as further indicators of food limitation.…”

Sources of variation in small rodent trophic niche: new insights from DNA metabarcoding and stable isotope analysis

“…For example, the results of refs. [9,11] suggest that intensive grazing by ungulates would reduce plant species richness, thus leading to a decreased TNW. High population densities of ungulates may persist over long time periods Downloaded by [Linnaeus University] at 23:59 09 October 2014 and indeed often have drastic effects on vegetation diversity [89][90][91].…”

“…Trophic niche width thus describes the size of trophic niche and can be measured as diversity of used food resources [5][6][7]. While a link between intraspecific competition and trophic niche width may exist for many consumers, the few studies that have investigated this relationship in herbivores suggest that different mechanisms may come into play [8][9][10][11]. High herbivore population density may directly induce a narrowing of the trophic as diversity of resource use, taking into account both the number of resources and relative intensity of their use [5][6][7].…”

Turning Pests into Profits: Introduced Buffalo Provide Multiple Benefits to Indigenous People of Northern Australia

“…Although buffalo are well-adapted to poor environments (Ford 1978(Ford , 1982McMahon et al 2010a;Moran 1986Moran , 1992, their calves are vulnerable to extended periods of harsh conditions. For example, increased juvenile mortality has been linked to the delayed onset of the monsoon season because buffalo rely heavily on the drinking water and germinated forage produced by late dry season rains (Freeland and Choquenot 1990). These physiological advantages and low maintenance requirements make buffalo a valuable resource for remote indigenous communities of northern Australia.…”