Biodiversity assessment and change: the challenge of appropriate methods

Introduction The Progressive Inclusion of Biodiversity Measures in Environmental Monitoring The recognition of the importance of monitoring within ecosystems emerged only since the mid twentieth century. The concept of biological indicators, as opposed to particular target ''headline'' organisms and the measurement of these alongside broader environmental parameters, was adopted in ecosystem monitoring with the establishment of the United Nations Environment Programme. 1 A formal recommendation to focus on biological diversity in biological monitoring appeared in the Brundtland Report.2 There followed widespread acceptance that the quality of air, water and soil can be monitored far more effectively with the use of indicator species than by environmental monitoring of chemical pollutants or climate alone.3 Early emphases of European monitoring programmes sought to gauge the state of marine fisheries under increasing harvesting, and forest health as affected by acid deposition, but this soon developed into surveillance of particular plant and animal species, where the conservation of biological diversity became a priority objective in certain European countries as concern mounted over habitat loss and declines in species.3,4 The CORINE Biotopes Programme was the first pan-European assessment of biotopes of major importance for nature conservation.5 The essential purpose of long-term monitoring was advocated in the UNEP Global Biodiversity Assessment, that such monitoring was critical ''to identify humanmade changes from natural changes''.6