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

Abstract

We compared the impacts on forest regeneration of introduced sika (Cervus nippon) and red (Cervus elaphus) deer in New Zealand. Plot data were used to compare mountain beech (Nothofagus solandri var. cliffortioides) regeneration between a region with sika deer, and four regions without sika deer. All regions surveyed had red deer present. In the region where sika deer had been present for more than a decade, there was evidence of poor mountain beech seedling regeneration. In the four regions without sika deer, there was evidence of a strong regenerative response at stands with low occupancy by trees. When compared to larger deer species, sika deer have a digestive morphology allowing greater dietary versatility, which may result in them impeding forest regeneration where red deer do not. In contrast to mountain beech, some small-leaved shrub species may have been competitively advantaged by intensive browsing from sika deer. This is contra to a current view that small-leaved shrub species with interlacing branches were able to tolerate browsing from extinct ratite birds, but not introduced deer. Sika deer have been introduced into countries where other deer species are indigenous, such as Canada, Denmark, Great Britain, Czech Republic, Ireland and the United States of America. Because of their dietary advantage, sika deer may have a greater potential to impede forest regeneration and competitively exclude larger deer species, particularly at low basal area sites where impacts on tree regeneration are likely to be greatest.

Effects of biological invasions on forest carbon sequestration

“…These direct effects can regulate recruitment, growth, and mortality of trees (e.g. Coomes et al, 2003;Husheer et al, 2006), with potentially important consequences for C sequestration (Waring & Schlesinger, 1985). Further, introduced herbivores can indirectly affect C in the soil through influencing the quantity and quality of resources returned to the soil, and several mechanisms have been proposed that can have either positive or negative consequences for net belowground C sequestration (e.g.…”

Soil‐mediated effects of invasive ungulates on native tree seedlings

“…Selective feeding on nutrient-rich plants often shifts competitive interactions among plants by favouring species of low palatability (e.g. Wardle et al 2001;Husheer, Allen & Robertson 2006;Barrios-Garcia, Relva & Kitzberger 2012). The same traits that confer low palatability to plants (i.e.…”

Phenotypic correlates of hybridisation between red and sika deer (genus Cervus)

“…In Scotland, sika deer have higher fertility rates than red deer (Chadwick, Ratcliffe & Abernethy 1996) and anecdotally, are harder to control, because of high alertness, preference for dense forest habitat and propensity to change their behaviour in response to culling pressure (Ratcliffe 1987; McLean 1993; Bartos et al. 1998; Husheer, Allen & Robertson 2006). In Scotland sika also show high resistance to infection by Elaphostrongylus spp ., lungworms common in red deer (Bohm et al.…”