Etude des relations forêt-cervidés en forêt domaniale d'Arc-en-Barrois (Haute-Marne)

“…In 1976, due to high deer populations, the northern part of the Arc-en-Barrois forest (the Arc-Châteauvillain forest) in north-eastern France was deemed suitable for studying the impacts of deer browsing on vegetation communities (Allain et al 1978). Indeed, roe deer, a browser, is likely to impact shrub cover and composition, and red deer, an intermediate feeder that consume not only ligneous but also herbaceous plants, is likely to alter ground flora.…”

Section: Introductionmentioning

confidence: 99%

Decreasing deer browsing pressure influenced understory vegetation dynamics over 30 years

Boulanger

Baltzinger²,

Saı̈d

et al. 2014

Annals of Forest Science

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Abstract& Key message Thanks to the concomitant recordings of vegetation and deer browsing sampled first in 1976, then resurveyed in 2006, we show that forest plant communities shifted in response to deer population dynamics, stand management and eutrophication. & Context and aims High deer populations alter forest understory dynamics worldwide. However, no study ever attempted to rank the importance of deer herbivory relatively to other environmental drivers. In the Arc-en-Barrois National Forest (France), we investigated whether (i) deer browsing is a critical driver of vegetation composition and dynamics, (ii) the vegetation communities recover after a decrease in deer populations. & Methods In 2006, we resurveyed 321 plots from a network of 1027 plots where vegetation composition and browsing pressure was first assessed in 1976. We used coinertia analysis to identify the gradients in vegetation composition in 1976, when abiotic variables were also recorded. We assessed shifts in plant community composition using mean Ellenberg indicator values, analysed plot scores shifts along the axes of the coinertia analysis and correlated these shifts with changes in browsing pressure. & Results Two major gradients determined vegetation composition in 1976: edaphic variables (nitrogen availability and soil moisture) and browsing pressure. Over the next 30 years, we noticed a strong increase in nitrophilous plant species frequency and community composition shifted towards lightly browsed characteristics, accompanying a decrease in browsing pressure. Shifts in community composition were significantly correlated with the intensity of changes in browsing pressure, showing that deer population dynamics were a determinant driver of changes in plant assemblages. We observed an incomplete recovery of the communities 25 years after the reduction of deer densities, suggesting a delayed response to deer population reduction. Long-term monitoring of forest biodiversity should therefore include browsing pressure assessment to control for potential effects of wild ungulates.

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“…Aldous (1944) was the first to establish a methodology for measuring deer browsing on woody species, allowing the estimation of the impact of deer on each plant species present along an ordinal scale of 6 levels in 40 m 2 plots. Originally build for a phytosociological study (Allain et al, 1978), the protocol proposed by Picard (1988) is based on a more qualitative scale and a larger area of browsing observation (400 m 2 ). Tested on three forests, this method revealed to be closer to the hunters and managers knowledge than animal counts.…”

Section: Introductionmentioning

confidence: 99%