Evaluating the impact of habitat translocation on grassland beetles and spiders using species richness, diversity, turnover, similarity and ordination

摘要

Pressure on land may lead to an increase in habitat translocation in future as a solution to objections to the development of sensitive areas. As yet, the effects of habitat translocation on plant, and particularly animal communities have been little studied because the practise is uncommon and monitoring is costly. This study reports on methods used to evaluate the impact of translocating 5ha of species-rich Magnesian limestone grassland on invertebrates. The spiders and beetles from the translocated site are compared with a control site prior to translocation in 1982 and subsequently in 1985 and 1988. Diversity and similarity indices and ordination of approximately 500 species grouped into six taxa were used to quantify change. A simple compartmental model based on ordination is suggested as a practical method which could be used to evaluate the response to habitat translocation. In the example studied, most groups showed signs of disturbance three years after translocation, but only two groups showed marked change after six years. In one of these the assemblage of the control site appeared to have changed more than that of the control and this was attributed either to inadequate pre-sampling or to succession due to change in management during the restoration process. In the second example, the translocated assemblage acquired large numbers of one species not present prior to translocation but still abundant after six years.