Management by proxy? The use of indices in applied ecology

encourages contributions thatcan inuence environmental management, policy or both,with evidence based on the most robust science possible.Natural resource management is often contentious, andany perceived weaknesses in the underpinning science areeasily exploited by interest groups to undermine the widerendeavour (see, e.g. the experiences of the Intergovern-mental Panel on Climate Change, Ravindranath 2010).Thus, the robustness of science designed to underpin man-agement and policy is particularly important.Unfortunately, robust and unambiguous results are dif-cult to obtain in ecology. In particular, causal pathways inecology are seldom linear, but are part of a ‘vast web ofcause and effect’ of which, typically, we can study only asmall part (Peters 1991; p. 134). Meaningful spatial andtemporal scales for ecological processes often defy experi-ments, controlled manipulations and adequate replication;most modern ecological science is reliant on observationaldata and correlation is far easier to demonstrate than cau-sation (