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Heavy metals are naturally present in soils but are significantly altered by anthropogenic activity which can pose both environmental and human health risks. Sixty green space reserves were chosen in New Zealand's largest city and separated into six site categories to determine the influence of site location, soil depth, underlying substrate, canopy cover, and distance from roads and central business district on soil heavy metals. Soils in native urban forests had the lowest pools (g [m.sup.-2]) of heavy metals compared with green spaces close to high-traffic, park, school, industrial and residential areas. Least variability in heavy metals was determined among forest sites, with variability increasing in the order: residential, school, industrial, park, and high-traffic sites. Using forest sites as a baseline, a 'pollution index' (PI) was established and deemed high for nickel, cadmium and copper and moderate for arsenic, zinc, chromium, lead and mercury. The mean 'integrated' PI was high at 3.3 (range 0.3-9.3), indicating elevated levels of soil pollution. The PI was considered a useful technique for interpreting data and complemented traditional ways of reporting concentrations of heavy metals through use of soil pools, which has been limited to date. This study provides important heavy metal data for use in determining where resources may be required to mitigate future risk of increased soil pollution. Additional keywords: canopy cover, New Zealand, pollution index, soil pools, urban soils, urban forests., Introduction Heavy metals are naturally present in soils and are predominantly inherited from the soil's parent material (Longhurst et al. 2004; Godt et al. 2006). However, concentrations of heavy metals [...]

Land fragmentation is a growing issue in New Zealand, however, no consistent or regular national monitoring has been established. A methodology for assessing land fragmentation was applied nationally for the first time, revealing that the greatest proportion of fragmentation occurred on land used for diffuse rural residence (>0.40 to ≤2.0 ha) and small parcels (>2.0 to ≤8.0 ha) with a 128% and 73% increase, respectively, between 2002 and 2019. In New Zealand, the most highly productive land (Land Use Capability (LUC) class 1, 2 and 3) is most impacted by continued fragmentation with 38%, 28% and 17% of baseline area, respectively, occupied by medium sized parcels or smaller (≤40.0 ha) with a dwelling in 2019. Impacts were greatest for Auckland with 40%, 44% and 25% of the region's LUC 1, 2 and 3 land, respectively, occupied by small sized parcels or smaller with a dwelling, increasing to 64%, 67% and 47%, respectively, when including parcels ≤ 40.0 ha. Protection of LUC class 1 and 2 land, particularly, requires national attention. This metric provides an opportunity to evaluate land fragmentation and development over time that could serve both the assessment of policy performance and environmental reporting at national and regional levels. [ABSTRACT FROM AUTHOR]

Bacterial communities are important for the health and productivity of soil ecosystems and have great potential as novel indicators of environmental perturbations. To assess how they are affected by anthropogenic activity and to determine their ability to provide alternative metrics of environmental health, we sought to define which soil variables bacteria respond to across multiple soil types and land uses. We determined, through 16S rRNA gene amplicon sequencing, the composition of bacterial communities in soil samples from 110 natural or human-impacted sites, located up to 300 km apart. Overall, soil bacterial communities varied more in response to changing soil environments than in response to changes in climate or increasing geographic distance. We identified strong correlations between the relative abundances of members of Pirellulaceae and soil pH, members of Gaiellaceae and carbon-to-nitrogen ratios, members of Bradyrhizobium and the levels of Olsen P (a measure of plant available phosphorus), and members of Chitinophagaceae and aluminum concentrations. These relationships between specific soil attributes and individual soil taxa not only highlight ecological characteristics of these organisms but also demonstrate the ability of key bacterial taxonomic groups to reflect the impact of specific anthropogenic activities, even in comparisons of samples across large geographic areas and diverse soil types. Overall, we provide strong evidence that there is scope to use relative taxon abundances as biological indicators of soil condition., Importance: The impact of land use change and management on soil microbial community composition remains poorly understood. Therefore, we explored the relationship between a wide range of soil factors and soil bacterial community composition. We included variables related to anthropogenic activity and collected samples across a large spatial scale to interrogate the complex relationships between various bacterial community attributes and soil condition. We provide evidence of strong relationships between individual taxa and specific soil attributes even across large spatial scales and soil and land use types. Collectively, we were able to demonstrate the largely untapped potential of microorganisms to indicate the condition of soil and thereby influence the way that we monitor the effects of anthropogenic activity on soil ecosystems into the future., (Copyright © 2016 American Society for Microbiology.)