Attrition of recommended areas for protection: clearance of ecologically significant vegetation on private land

Abstract

The area of indigenous vegetation and habitat remaining on New Zealand's primary agricultural lands continues to decrease, but it has been difficult to obtain reliable estimates of the extent and causes of loss. We assess change and identify predictors of vegetation clearance in 856 recommended areas for protection (RAPs) from 35 ecological districts in the North and South Islands, New Zealand, for the period 1989 to 2015. Over 27 years, 7152 ha of these RAPs were cleared (2.3% by area), with rates varying over space and time. Native forest was least commonly cleared (422 ha removed), followed by native non-woody vegetation (1294 ha), native shrubland (1378 ha), and 'other' vegetation (4058 ha). The probability of clearance peaked during 2001 to 2008 at 0.14% yr-1 , but it was still nearly double the 1989-2001 levels (0.06% yr-1) from 2008 to 2015 (0.11% yr-1). The annualised clearance probabilities after 2001 were comparable to the rates of deforestation in the pre-1840 period of human settlement and about a third of that recorded from 1840 to 1970, the most intensive known period of anthropogenic clearance in New Zealand. Clearance rates were higher around the edges of small RAPs without legal protection and in drier, cooler areas, generally and increasingly over time. Amount of surrounding cropping/horticulture was negatively associated with clearance, as initially was dairy before developing a slightly positive association. Forestry was positively associated with clearance up until 2008. Our results show proportionally greater clearance of marginal agricultural land with high biodiversity values as time goes on, probably facilitated by the increasing use of technology, such as irrigation and fertilisation, to circumvent environmental limitations to plant growth. These results demonstrate ongoing attrition of the highest-value native habitat remaining on private land, and the inadequacy of the current protection framework to safeguard it.

Large-scale tree planting initiatives as an opportunity to derive carbon and biodiversity co-benefits: a case study from Aotearoa New Zealand

“…It is also critical to consider the biodiversity impacts of tree planting initiatives on nontree ecosystems. Concerns have been raised about new trees being planted over native scrubland, grasslands, and other naturally occurring ecosystems, degrading the distinct biodiversity value of these areas (Eder 2019;Monks et al 2019;Veldman et al 2015). Biosecurity issues, such as the spread of kauri dieback disease (Bradshaw et al 2020) and myrtle rust (Toome-Heller et al 2020) need to be better considered as does the unintentional spread of wilding Pinus radiata from mass-planting sites and into adjacent ecosystems (Hulme 2020).…”

“…Tree planting initiatives must also consider the impacts of new plantings to biodiversity of non-tree ecosystems at potential planting sites. Replacing grasslands, savannas, wetlands and other non-tree ecosystems with trees overlooks the existing biodiversity value of these areas (Monks et al 2019;Veldman et al 2015) and can release the carbon already stored in these systems (Lewis et al 2019). Expanding tree planting means finding new areas to plant trees, but existing habitats and changes in land use should also be considered when selecting new sites.…”

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.…”

Movements and habitat connectivity of New Zealand forest birds: a review of available data

“…The New Zealand landscape was transformed by two waves of human colonisation that removed most indigenous forest cover (Walker et al 2006;Sullivan et al 2010). Indigenous forest now covers only 24% of New Zealand, compared with 82% at the time of human settlement (Ewers et al 2006) and fragmentation is continuing (Ausseil et al 2011;Monks et al 2019). Since human arrival one-third of all New Zealand birds have become extinct.…”