Deer reduce habitat quality for a woodland songbird: Evidence from settlement patterns, demographic parameters, and body condition

Holt, Chas A.; Fuller, Robert; Dolman, Paul M.

doi:10.1525/auk.2012.12090

Cited by 13 publications

(7 citation statements)

References 45 publications

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“…Mechanistically, declines occur when browsing reduces territory quality, individual condition and demographic performance by increasing predation rates, eliminating substrates necessary for reproduction and reducing food supply (e.g. deCalesta, 1994;McShea & Rappole, 2000;Martin & Joron, 2003;Martin & Possingham, 2005;Stockton et al, 2005;Cardinal et al, 2012;Holt et al, 2013). Intense browsing can similarly enforce the extirpation of palatable plants without refuge from deer by reducing plant survival, reproduction and patch recolonization rates below those needed to maintain local or regional persistence (e.g.…”

Section: Introductionmentioning

confidence: 99%

Deer density and plant palatability predict shrub cover, richness, diversity and aboriginal food value in a North American archipelago

Arcese

Schuster

Campbell

et al. 2014

Diversity and Distributions

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Aim Trophic cascades are a common consequence of herbivore outbreak and in the absence of hunting can cause the local extinction of native plant species and communities. We compared plant communities at 66 island and mainland sites to test the hypothesis that deer (Cervidae) determine species cover, richness and diversity and that palatable species become rare at high deer density. We validate a region-wide index of deer density and impact on plant communities in a region where culturally significant food plants maintained by aboriginal people prior to European contact helped to define baseline plant communities.Location Gulf and San Juan Island archipelagos and North American mainland.Methods We conducted surveys of 49 native, 10 exotic and 15 culturally significant plant species and deer sign at 66 sites on 35 islands and mainland to determine deer abundance and plant species cover, richness and diversity. We identified culturally significant food plants facilitated by aboriginal people using ethnobotanical knowledge, quantified plant palatability via cafeteria trials and characterized shrub architecture.Results Native and culturally significant shrub cover, richness and diversity were 52-85% lower at sites with abundant deer (0.9-2.8 ha À1 ) versus no deer. However, these values were also 38-82% lower at sites in the lowest deer density class (< 0.08 ha À1 ) versus sites with no deer present. Palatable cover was 92% lower where deer were abundant versus absent and 28% lower in low-density versus deer-free sites. Shrub architecture provided an easily applied index of native and culturally significant plant cover and deer density.Main conclusions We provide comparative examples of endangered plant communities to demonstrate that, contrary to the intermediate disturbance hypothesis, any positive effect of deer on plant diversity on islands in the Pacific north-west of North America occurs at densities < 0.08 ha À1 , if at all. This detailed example of trophic downgrading highlights the need and provides the methods to identify herbivore densities compatible with the persistence of all native species in conserved landscapes.

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Section: Introductionmentioning

confidence: 99%

Deer density and plant palatability predict shrub cover, richness, diversity and aboriginal food value in a North American archipelago

Arcese

Schuster

Campbell

et al. 2014

Diversity and Distributions

View full text Add to dashboard Cite

show abstract

“…This suggests that there may have been a greater density of territorial male Blackcaps in the protected coppice and a higher proportion of non‐singing (floaters) birds in coppice with deer, an indication of superior quality of unbrowsed habitat for this species (Holt et al . ).…”

Section: Discussionmentioning

confidence: 97%

“…For example, Holt et al (2011) found no difference between exclosures and control sub-plots in terms of total mist-netting captures of Eurasian Blackcaps, but the point count data in this paper showed a positive response to exclusion of deer. This suggests that there may have been a greater density of territorial male Blackcaps in the protected coppice and a higher proportion of non-singing (floaters) birds in coppice with deer, an indication of superior quality of unbrowsed habitat for this species (Holt et al 2013).…”

Section: Spring and Winter Bird Assemblages: General Patternsmentioning

confidence: 99%

Exclusion of deer affects responses of birds to woodland regeneration in winter and summer

Holt

Fuller

Dolman

2013

Ibis

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Using an exclosure experiment in managed woodland in eastern England, we examined species and guild responses to vegetation growth and its modification by deer herbivory, contrasting winter and the breeding season over 4 years. Species and guild responses, in terms of seasonal presence recorded by multiple point counts, were examined using generalized linear mixed models. Several guilds or migrant species responded positively to deer exclusion and none responded negatively. The shrub-layer foraging guild was recorded less frequently in older and browsed vegetation, in both winter and spring. Exclusion of deer also increased the occurrence of ground-foraging species in both seasons, although these species showed no strong response to vegetation age. The canopy-foraging guild was unaffected by deer exclusion or vegetation age in either season. There was seasonal variation in the responses of some individual resident species, including a significantly lower occurrence of Eurasian Wren Troglodytes troglodytes and European Robin Erithacus rubecula in browsed vegetation in winter, but no effect of browsing on those species in spring. Ordinations of bird assemblage compositions also revealed seasonal differences in response to gradients of vegetation structure generated by canopy-closure and exclusion of deer. Positive impacts of deer exclusion in winter are probably linked to reduced thermal cover and predator protection afforded by browsed vegetation, whereas species that responded positively in spring were also dependent on a dense understorey for nesting. The effects on birds of vegetation development and its modification by herbivores extend beyond breeding assemblages, with different mechanisms implicated and different species affected in winter

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“…is that for a given level of deer pressure and a given stage of forest development, habitat quality for understorey‐dependent species will be positively related to the extent to which canopy cover is reduced. This could be initially tested for a widespread species such as blackcap Sylvia atricapilla for which there is evidence that deer browsing reduces habitat quality (Holt, Fuller & Dolman ).…”

Section: Management Treatments and Ecological Resourcesmentioning

confidence: 99%

FORUM: Searching for biodiversity gains through woodfuel and forest management

Fuller

2013

Journal of Applied Ecology

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Summary1. Woodfuel extraction from established woods and forests is promoted in Western Europe as a renewable energy source. Woodfuel management is mainly carried out by silvicultural thinning or short-rotation harvesting, including coppicing. Potential negative effects include reduction in habitat quality for saproxylic species. However, in some regions, habitats may be improved for species that have declined as a result of increased shading. Resources required by most of these species are more likely to be delivered by short-rotation management than thinning. 2. Relatively little is documented on the effects of thinning intensity on ecological resources and biodiversity within European forests. Trade-offs between canopy cover, deer browsing pressure and understorey complexity are likely to occur. Therefore, interactions between thinning treatments and deer browsing potentially affect biodiversity, in the context of both woodfuel and timber production. 3. Synthesis and applications. Woodfuel management is unlikely to deliver benefits for most shade-intolerant species unless it creates substantial areas of young-growth with low deer impacts. However, more research is needed on thinning as a potential conservation tool. Changing climate and tree diseases are creating an uncertain future for forest management. It is timely for ecologists to work with forest managers to identify how integrated forestry and deer management can deliver positive and balanced biodiversity outcomes.

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Deer reduce habitat quality for a woodland songbird: Evidence from settlement patterns, demographic parameters, and body condition

Cited by 13 publications

References 45 publications

Deer density and plant palatability predict shrub cover, richness, diversity and aboriginal food value in a North American archipelago

Deer density and plant palatability predict shrub cover, richness, diversity and aboriginal food value in a North American archipelago

Exclusion of deer affects responses of birds to woodland regeneration in winter and summer

FORUM: Searching for biodiversity gains through woodfuel and forest management

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