Characteristics of tree seedlings and neighbouring vegetation have an additive influence on browsing by generalist herbivores

Conifer leader browsing by roe deer in English upland forests: Effects of deer density and understorey vegetation

“…These should ideally be tested experimentally, using plots of different deer density/ understorey vegetation availability combinations. Nevertheless, an abundance of circumstantial evidence arising from similar studies to this provides support for the associational plant refuge hypothesis for a diversity of herbivores (Gill, 1992;VerheydenTixier et al, 1998;Moser et al, 2006;Miller et al, 2006), which should be considered when planning deer damage management programmes.…”

“…Pfister and Hay (1988) described the associational plant refuge hypothesis, whereby certain plant species are protected from foraging impacts due to the presence of more palatable species nearby. Miller et al (2006) provided support for this hypothesis for generalist herbivores foraging on tree saplings in Australia and Verheyden-Tixier et al (1998) and Moser et al (2006) found a similar association between roe deer (Capreolus capreolus) browsing impacts to deciduous tree saplings and local vegetation abundance and quality. However, the functional form of the relationship between impacts and ungulate density has rarely been reported and effects that other, habitatrelated variables, such as local vegetation community structure, might have on this relationship have generally only been qualitatively addressed.…”

“…However, their study site contained sympatric populations of red and roe deer. Intermediate feeders (such as red deer) and bulk feeders (such as fallow deer, Dama dama) may respond differently than concentrate selectors (such as roe deer) to environmental factors, including vegetation structure (Miller et al, 2006). Moreover, out-competition of roe deer by red deer (Staines and Welch, 1984) may confound effects that roe deer might have on conifers in the absence of red deer.…”

Effects of livestock exclusion on tree regeneration in church forests of Ethiopia

“…Eventually, the tree canopy thins out and disappears (Blackmore and Vitousek, 2000;Carolina and Javier, 2001;Fleischner, 1994;Opperman and Merenlender, 2000;Ramirez-Marcial et al, 2001;Scowcroft, 1983;Stone, 1985). Grazing by animals can reduce forest productivity through a reduction in seedling growth rate and survival, and by changing tree form (Bulinski and McArthur, 1999;Miller et al, 2006;Wilkinson and Neilsen, 1995). Three main components of structural change have been identified in a grazed forest: browsing on seedlings which limits stem density; browsing on leading shoots which limits height growth; and browsing on side shoots and climbers which reduces foliage density (Gill and Beardall, 2001;McEvoy et al, 2006).…”

Native plant/herbivore interactions as determinants of the ecological and evolutionary effects of invasive mammalian herbivores: the case of the common brushtail possum

“…These show that repeated browsing on eucalypts has clear fitness effects. For example, browsing on seedlings removed up to 80% of foliage after a 16 week period (Miller et al 2006) and repeated browsing in the field reduced seedling survival and growth rates (Bulinski and McArthur 1999). Repeated browsing also significantly reduced the reproductive output of Eucalyptus nitens at 10 years of age compared with trees that received no browsing (J. M. O'Reilly-Wapstra, unpublished data).…”