Effects of White-tailed Deer (Odocoileus virginianus) on Plants, Plant Populations and Communities: A Review

Abstract

Large effects of white-tailed deer (Odocoileus virginianus) upon individual plants, plant populations and communities have been documented in a number of studies. However, well-supported experimental measures of the magnitude and geographical extent of these effects are still surprisingly scarce. Deer-caused changes in stem morphology and reductions in plant growth rates are well-documented in some parts of the North America. Furthermore, deer have been shown to affect the composition of several plant communities in the north-central and northeastern United States. There are some documented cases of deer-caused reductions in plant survival; most of these are tree seedlings and saplings. However , many studies have detected no effects on plant survival or fecundity, or have found that negative effects occur only in a fraction of years, seasons, sites or deer densities. Little is known about population-level or ecosystem-level impacts. Many regions and plant communities with large deer populations have not been studied. Whereas deer density is clearly important in determining spatial and temporal variation in the presence and magnitude of deer effects, other factors that may modify the effects of deer density are poorly understood.

Deer herbivory affects the functional diversity of forest floor plants via changes in competition‐mediated assembly rules

“…The former includes selective herbivory that is associated with the palatability of plants (Augustine and McNaughton 1998), while the latter is exemplified by changes in habitat conditions due to browsing that can result in gap formation and altered nutrient cycling (Wardle et al 2002;Bardgett and Wardle 2003). As a result, the structure, composition, and diversity of plant communities can be substantially altered (Russell et al 2001;Horsley et al 2003). To safeguard vegetation from overgrazing by ungulates, fences designed to exclude these large herbivores have often been established in various regions, but their effects on local plant diversity have been mixed (Coˆte´et al 2004;Inatomi et al 2012).…”

Population growth rate of a common understory herb decreases non-linearly across a gradient of deer herbivory

“…Increases in the density of white-tailed deer (Odocoileus virginianus), and the resulting increase in herbivory of forest understory plants, is a striking example of human-mediated change in a biotic interaction (McCabe and McCabe 1997, Russell et al 2001, Côté et al 2004). …”

“…Because deer are generalist herbivores, most palatable forest understory species are currently experiencing unprecedented herbivore pressure (McCabe and McCabe 1997, Russell et al 2001, Côté et al 2004. Worldwide, deer and other large ungulate browsers threaten forest and agricultural ecosystems because their dense populations can inhibit forest plants' regeneration and reduce crop yield (Tilghman 1989, Inouye et al 1994, Waller and Alverson 1997Persson et al 2000;Rooney 2001, Russell et al 2001, Augustine & DeCalesta 2003, Horsley et al 2003, Côté et al 2004). …”

“…High local deer densities have been shown to reduce overall plant biomass, shift community composition from more to less palatable plant species, and dramatically reduce overall plant biodiversity (Russell et al 2001, Rooney and Waller 2003, Côté et al 2004, Wiegmann and Waller 2006, Royo and Carson 2006. Deer-mediated decline of many previously abundant herbaceous understory species has created conservation concern (e.g.…”

Suppression of Regeneration in New Zealand Mountain Beech Forests is Dependent on Species of Introduced Deer

“…Stand occupancy is frequently measured by tree basal area, which is a measure of the area that trees cover and is related to tree biomass. The effects of herbivores are often strongly related to stand occupancy (Russel et al 2001;Horsley et al 2003). Despite this, few studies in temperate forests have considered the impacts of herbivores on canopy tree regeneration within a context of stand occupancy (but see Castleberry et al 2000;Cornett et al 2000;Husheer and Frampton 2005).…”