The ecological impact of recreation in British temperate woodlands
In recent decades, the ecological impact of recreation in woodlands and forests has been a subject of considerable world-wide interest. However, there are few studies examining the effects of recreation on woodland vegetation, soils and fauna in Britain. This thesis identifies recreational trampling as a major contributor in facilitating ecological change in urban fringe semi-natural ancient temperate woodlands of Warwickshire, England. Relationships with trampling intensity are generally curvi- linear, suggesting that the rates of damage are most rapid at initial stages of trampling. Biotic communities are shaped so that their structure and diversity is related to the type, intensity and frequency of impact. The impact of trampling on vegetation is the most precise indicator of recreational use. Multi-variate analyses indicates that trampling is the primary organisational gradient operating on ground vegetation, with trail centres dominated by secondary plant associations at equilibrium with the trampling pressure. Trail margins are dominated by vegetation that is tolerant of low levels of trampling and high rates of competition. Experimental trampling experiments show that the ecological carrying capacity of woodlands for recreation are lower than previously thought; from below 150 people per year in Rubusfruticosus agg. and Pteridium aquilinum dominated stands to below 75 people per year in coniferous stands with Hyacinthoides non-scripta ground flora. The ability of vegetation to tolerate trampling is related to plant anatomy, morphological adaptations, plant strategies, growth rate, position of the perennating bud, environmental conditions such as canopy density and is more a function of the ability to recover from trampling rather than to resist. By virtue of their delicate morphology, stands dominated by shade tolerant species are the most vulnerable to trampling. Increases in soil compaction and decreases in pore space and oxygen content are recognised as important in shaping woodland vegetation and fauna, and the reduction in soil inhabiting invertebrate and micro-organism populations have consequences for woodland processes. A bioindicator index to assess soil damage is provided using Acari body length. Models summarising the ecological changes associated with trampling and the ecological carrying capacity of woodlands are provided, along with a woodland management checklist and an index of vulnerability for resource managers to assess the potential of woodland stands to withstand recreational use.