Arthropods and biofuel production systems in North America

Abstract Biomass harvest may eventually be conducted on over 100 000 000 ha of US crop and forest lands to meet federally-mandated targets for renewable biofuels. Such large-scale land use changes could profoundly impact working landscapes and the arthropod communities that inhabit them. We review the literature on dedicated biofuel crops and biomass harvest from forests to look for commonalities in arthropod community responses. With expanded biofuel production, existing arthropod pests of biofuel crops will likely become more important and new pests will emerge. Beneficial arthropods will also be influenced by biofuel crop habitats, potentially altering the distribution of pollination and pest control services to the surrounding landscape. Production of biofuel crops including initial crop selection, genetic improvement, agronomic practices, and harvest regimes will also influence arthropod communities. In turn, arthropods will impact the productivity and species composition of biomass production systems. Some of these processes have the potential to cause landscape-level changes in arthropod community dynamics and insect-vectored plant diseases. Finally, changes in arthropod populations and their spatiotemporal distribution in the landscape will have impacts on consumers of insects at higher trophic levels, potentially influencing their population and community dynamics and producing feedbacks to arthropod communities. Given that dedicated biofuel crops and intensified biomass harvest from forests are still relatively uncommon in North America, as they increase, we anticipate ‘predictably unpredictable’ shifts in arthropod communities and the ecosystem services and functions they support. We suggest that research on arthropod dynamics within biofuel crops, their spillover into adjacent habitats, and implications for the sustainability of working landscapes are critical topics for both basic and applied investigations.     

广州地区荷木夜间树干液流补水的影响因子及其对蒸腾的贡献

明确树木夜间水分补充现象有助于提高总蒸腾量和冠层气孔导度估算的精确度,进一步认识冠层蒸腾与树干液流之间存在的时滞关系.本研究采用热消散探针法测定了广州地区的荷木树干液流密度,同步监测了主要的环境因子,从不同时间尺度分析了树干夜间液流的水分补充现象.结果表明：与白天相比,荷木夜间液流密度较小,旱季变化幅度比湿季大;夜间水分补充的时间段主要在前半夜(18:00-22:00);年内各季节夜间水分补充量之间没有显著差异,与环境因子之间的偏相关关系不显著,但与胸径、树高、冠幅、树干生物量、冠层生物量的回归曲线拟合很好,表明树形特征和生物量能更好地解释夜间补水的变化;各季节夜间水分补充量对总蒸腾量的贡献有显著差异,旱季明显高于湿季.     

Impacts of traditional land uses on biodiversity outside conservation areas: effects on dung beetle communities of Vaalbos National Park

Grazing is one of the key processes in terrestrial ecosystems and this can be provided by both indigenous and domestic ungulates. However, a question remains whether or not traditional forms of land use such as the grazing of domestic animals support the maintenance of biodiversity. If it does not, then the second question becomes to what extent does grazing of domestic animals alter the systems and processes that support biodiversity? This study demonstrates that in attempting to answer this question, small organisms like dung beetles are ideal indicators that can be used to express significant differences between conserved (indigenous) and non‐conserved (domestic) land. As a general trend, studies that investigated these differences displayed differences through analysis of the diversity indices. This method has in most cases demonstrated a lack of contrast between conserved and non‐conserved land. In the existence of such uncertainty this study has demonstrated that in such cases, where the analysis of biodiversity indices fail to demonstrate significant differences a closer examination of actual species such as guilds and functional groups could confirm significant differences between conserved and non‐conserved land. These apparently conflicting findings reflect the need to consider the actual elements of biodiversity (e.g. species) when assessing conservation issues rather than just the statistical measures of biodiversity.     

Terrestrial models and global change: challenges for the future

A wide variety of models have illustrated the potential importance of terrestrial biological feedbacks on climate and climate change; yet our ability to make precise predictions is severely limited, due to a high degree of uncertainty. In this paper, after briefly reviewing current models, we present challenges for new terrestrial models and introduce a simple mechanistic approach that may complement existing approaches.     

The NSW Environmental Services Scheme: Results for the biodiversity benefits index, lessons learned, and the way forward

Summary   In 2002 the Environmental Services Scheme (ESS) was launched in New South Wales, Australia. Its aim was to pilot a process to provide financial incentives to landholders to undertake changes in land use or land management that improved the status of environmental services (e.g. provision of clean water, healthy soils, biodiversity conservation). To guide the direction of incentive funds, metrics were developed for use by departmental staff to score the benefits of land use or land management changes to a range of environmental services. The purpose of this paper is to (i) report on the development of one of these metrics – the biodiversity benefits index; (ii) present the data generated by field application of the metric to 20 properties contracted to the ESS; and (iii) discuss the lessons learned and recent developments of the metric that aim to make it accessible to a wider range of end-users and applications.