Red deer habitat management in the Highlands: Consequences for invertebrates

Abstract

In Scotland, the well documented increase in the red deer population is widely regarded as a cause for concern, due to potentially detrimental impacts of grazing. This has lead to conflicting objectives between conservation and deer managers, despite the extent of the increase and the resulting impact both being hotly debated issues. Upland heather moorland is of international conservation importance while woodland habitats are some of the most stable ecosystems in anthropogenic landscapes. In the UK oak woodland plays a crucial role in the maintenance of biodiversity, and both heather moorland and oak woodland may be subject to degradation or decline due to grazing. This study is based in north-west Scotland, and investigates the consequences of two deer management strategies, in two habitat types, for invertebrates. An observational study of heather moorland under two extremes of grazing pressure provided little evidence for negative impacts of grazing on invertebrates on the more heavily grazed Letterewe Estate, suggesting that the deer population is not a cause for concern in terms of invertebrate biodiversity. An experimental study of grazed and un-grazed oak woodland found some positive effects, and no instances of negative grazing impacts on invertebrate biodiversity, and no effect on guild structure. This work highlights the need for science to inform land management policy that must often seek to balance conservation objectives with economic interests, and supports the notion that a red deer herd of a size consistent with viable stalking interests can be integral to the maintenance of biodiversity and the natural heritage.