Applying systematic conservation planning principles to palustrine and inland saline wetlands of New Zealand

Abstract

Previous attempts to identify nationally important wetlands for biodiversity in NewZealand were based on expert panel opinions because quantitative approaches were hampered by a lack of data. We apply principles of systematic conservation planning to remote sensing data within a geographical information system (GIS) to identify nationally important palustrine and inland saline wetlands. 2. A catchment-based classification was used to divide New Zealand into 29 biogeographic units. To meet representation goals, all wetland classes need to be protected within each unit. 3. We mapped current and historic wetlands down to a minimum size of 0.5 ha. Over 7000 current wetlands were mapped using standardised satellite imagery and a collection of point or polygon data. Historical extent was estimated from soil information refined using a digital elevation model. The current extent of wetlands is 10% of the historic extent, which is consistent with previous estimates. 4. A classification was produced using fuzzy expert rules within a GIS to identify seven wetland classes: bog, fen, swamp, marsh, pakihi ⁄ gumland, seepage and inland saline. Swamps and pakihi ⁄ gumland are the most common, but the former has sustained the greatest reduction in area with only 6% of its historical extent remaining. A preliminary field assessment of classification accuracy in the Otago region found only 60% agreement, mainly because of the misclassification of marshes into swamps. 5. Wetland condition was estimated using six measures of human disturbance (natural cover, human-made impervious cover, introduced fish, woody weeds, artificial drainage and nitrate leaching risk) applied at three spatial scales: the wetland's catchment, a 30-m buffer around the wetland and the wetland itself. Measures were transformed and combined into a single condition index. More than 60% of remaining wetlands had condition indices <0.5, probably indicating moderate to severe degradation and loss of native biodiversity. 6. Sites were ranked within each biogeographic unit using the wetland classification to ensure a representative set of wetland diversity. Rankings were determined by combining condition and complementarity to calculate conservation effectiveness that was then weighted by irreplaceability. Highest ranked sites in each biogeographic unit were usually the largest remaining wetlands that contained multiple wetland classes. This reflects their potential to protect a diverse range of wetland classes and a high proportion of the remaining habitat.

Biological Invasions in Conservation Planning: A Global Systematic Review

“…MARXAN was used for systematic conservation planning Tulloch et al, 2014 Terrestrial Protect Three management zones for fox were planned: (1) no fox management, (2) low-intensity management (2 baiting events per year), (3) high-intensity management (4 baiting events per year)-−17% operational objectives for the distribution of the target species. Prioritization of sites was based on spatially explicit biodiversity values, feasibility and management costs, and estimates of cost effectiveness Ausseil et al, 2011 Transitional Avoid Identification of an optimal set of wetland sites by sequentially choosing wetlands that contribute most to a measure of condition and complementarity. Condition was used to give less importance to wetland sites with degraded ecological integrity.…”

“…Hence, invasive alien species were avoided through the selection of habitats that were in good condition, i.e., less affected by cumulative impacts. Ausseil et al (2011) developed a systematic conservation routine in R for the identification of an optimal set of wetland sites by sequentially choosing wetlands that contribute most to the preservation of national wetland biodiversity. The selection criteria were: (1) naturalness condition; (2) complementarity with already selected sites; and (3) irreplaceability.…”

“…Specifically in the marine environment, the approaches that have been followed so far were to either protect alien biodiversity by setting conservation targets in MARXAN for both native and alien species (Giakoumi et al, 2011), or by estimating cumulative impact indices that included invasive alien species and either incorporate them in the cost function (Tallis et al, 2008), or adequately modify the optimization algorithm of MARXAN (Klein et al, 2013). All the other approaches applied in the freshwater or terrestrial environments can be transferred to the marine environment as well, i.e., exclusion of highly impacted areas Rouget et al, 2003;Pierce et al, 2005;Olson et al, 2010;Reid et al, 2012;Sealey et al, 2014), maximizing contribution to measures of condition and complementarity (Ausseil et al, 2011), or applying a least-cost path analysis including invasive alien species in the cost matrix (Lagabrielle et al, 2009). …”

Provision of Natural Habitat for Biodiversity: Quantifying Recent Trends in New Zealand

“…Ausseil et al (2011) have improved the accuracy of wetland mapping and identified changes since pre-European time. These recent analyses, together with the LUM, permit a synthesis of information for assessing recent trends of natural habitat provision in New Zealand.…”

“…The decline in many native freshwater fish is also attributed to the loss and degradation of wetlands (Sorrell & Gerbeaux, 2004). Ausseil et al (2011) estimated that the pre-human extent of wetlands was about 2.4 million ha, that is, about 10% of the New Zealand mainland. The latest extent (mapped in 2003) was estimated at 250,000 ha or 10% of the original coverage.…”