We compared four remote sensing methods to detect changes in New Zealand's grasslands (image differencing, normalised difference vegetation index (NDVI) differencing post‐classification and visual interpretation). The visual interpretation resulted in the best classification results, with a 98% overall accuracy when compared with ground‐truthed data. The tests on automatic classification (image differencing, NDVI differencing) and post classification had much lower accuracies, ranging from 47% to 56%. In the New Zealand grassland landscape, automatic detection methods were not able to differentiate between variations of soil moisture and vegetation phenology from variations in land‐use change. This, in combination with topographic effects, which have hampered the automated mapping of vegetation, is the main reason why visual interpretation of high‐resolution imagery is still needed.

New Zealand’s freshwater ecosystems support a diverse and unique array of endemic flora and fauna. However, the conservation of its freshwater biodiversity is often overlooked in comparison to terrestrial and marine environments, and is under increasing threat from agricultural intensification, urbanisation, climate change, invasive species, and water abstraction. New Zealand has some of the highest levels of threatened freshwater species in the world with, for example, up to 74% of native freshwater fish listed as endangered or at risk. Threatened species are often discounted in water policy and management that is predominantly focussed on balancing water quality and economic development rather than biodiversity. We identify six clear actions to redress the balance of protecting New Zealand’s freshwater biodiversity: 1. change legislation to adequately protect native and endemic fish species and invertebrates, including those harvested commercially and recreationally; 2. protect habitat critical to the survival of New Zealand’s rare and range-restricted fish, invertebrate and plant freshwater species; 3. include river habitat to protect ecosystem health in the National Objectives Framework for the National Policy Statement for freshwater; 4. establish monitoring and recovery plans for New Zealand’s threatened freshwater invertebrate fauna; 5. develop policy and best management practices for freshwater catchments in addition to lakes and rivers to also include wetlands, estuaries, and groundwater ecosystems; and 6. establish, improve, and maintain appropriately wide riparian zones that connect across entire water catchments. We have published these recommendations as a scientific statement prepared for the Oceania Section of the Society for Conservation Biology to facilitate communication of our thoughts to as wide an audience as possible (https://conbio.org/images/content_groups/Oceania/Scientific_Statement_1_.pdf, accessed 8 February 2016).

SUMMARYEffective conservation planning must anticipate the rates and patterns of dynamic threats to biodiversity, such as rapid changes in land use. Poor understanding and prediction of drivers and patterns of conversion of habitat can hinder assessments of the relative vulnerability of areas of remaining indigenous habitat to conversion, and identification of habitats in most immediate need of protection. Methods developed to model vulnerability to conversion vary in their complexity and applicability to conservation management. Generalized additive models provide a simple robust method to explore predictors and patterns of land-use conversion, and may be used to predict future patterns of conversion using recent land conversion data. This paper provides the first data-derived and statistically validated measurement of the vulnerability of New Zealand's indigenous grasslands to conversion. Higher altitude and more marginal (for agriculture and forestry) land showed greater conversion, and models based on earlier conversion patterns performed more poorly in predicting current patterns of conversion. Up-to-date land conversion data appear crucial for accurately predicting future vulnerability to habitat conversion.

Data needed for informed conservation prioritization are generally greater than the data available, and surrogates are often used. Although the need to anticipate threats is recognized, the effectiveness of surrogates for predicting habitat loss (or vulnerability) to land-use change is seldom tested. Here, we compared properties of two different vulnerability surrogates to validated vulnerability-validated prediction of habitat conversion based on a recent assessment of land-use change. We found that neither surrogate was a particularly effective predictor of vulnerability. Importantly, both surrogates performed poorly in places most imminently threatened with habitat conversion. We also show that the majority of areas protected over the last two decades have low vulnerability to the most active threatening process in this biome (habitat conversion). The contrary patterns of vulnerability and protection suggest that use of validated vulnerability would help to clarify protection needs, which might lead to the improvement of conservation decisions. Our study suggests the integration of validated vulnerability into conservation planning tools may be an important requirement for effective conservation planning in rapidly changing landscapes. We apply our results to discuss the practical considerations and potential value of incorporating validated vulnerability into conservation planning tools both generally and in the context of New Zealand's indigenous grasslands.