What effects must be avoided, remediated or mitigated to maintain indigenous biodiversity?

Abstract

New Zealand’s Resource Management Act requires avoiding, remedying or mitigating effects of human activities on the environment, including taking action to maintain terrestrial indigenous biodiversity. Here, we suggest that maintaining biodiversity requires halting its current decline, and to achieve that, New Zealand must move away from deeming only significant ecosystems and biota worthy of protection. We identify effects that must be avoided in order to maintain biodiversity, and those to be avoided unless they can be fully and promptly remediated. Effects should be avoided that reduce the extent and quality of most ecosystems and the habitats of indigenous species, including many highly modified ecosystems and habitats. Effects can be remediated only for a few, usually low-diversity and recently-established indigenous ecosystems and habitats, and we suggest a human generation (25 years) should be the maximum time to full remediation. Effects on individuals from some species’ populations (but not populations at range or environmental limits, or outliers) may be remediated through replacement in certain circumstances. The clearance and modification of young (< 25 years), non-indigenous, non-riparian ecosystems that are neither important for connectivity and buffering nor habitat for threatened or at-risk indigenous species, may have a limited adverse effect on maintaining biodiversity, but could compromise ecosystem services and remove opportunities for future restoration. The approach to avoidance we suggest would help to slow the cumulative and ongoing loss of terrestrial biodiversity caused by multiple minor effects.

Establishing an evidence-based framework for the systematic conservation of New Zealand’s terrestrial ecosystems

“…Importantly, Zonation uses a complementarity-based scoring algorithm (Margules et al 1988;Vane-Wright et al 1991;Moilanen et al 2009a) designed to assess the ability of groups of sites to collectively contribute to the representation of a full range of biodiversity features; this includes identification of sites that are irreplaceable because they support features occurring at few or no other sites. Its comparative, landscapescale rankings considerably extend the information provided by the site-by-site scoring-based procedure (Myers et al 1987;Walker et al 2008) used to identify significant natural areas under the NPSIB (Ministry for the Environment 2023, Appendix I). The latter provides only limited information about the relative contribution of individual sites to the representation of a full range of biodiversity on a landscape, risking the loss of those ecosystems whose surviving examples are all in very poor condition (Kirkpatrick 1983).…”

Poorly designed biodiversity loss-gain models facilitate biodiversity loss in New Zealand

“…Like the rest of the world, there is evidence that biodiversity loss driven by development (e.g. infrastructure, resource extraction, urban expansion, intensification of farming) is occurring in Aotearoa/New Zealand (Walker et al 2006;Myers et al 2013; Parliamentary Commissioner for the Environment 2015; Monks et al 2019;MfE & Stats NZ 2021). Of the nearly 11 000 terrestrial species assessed under the Aotearoa/ New Zealand Threat Classification System 811 species (7%) are ranked as Threatened and 2416 species (22%) At Risk.…”