ABSTRACT This study has investigated the status of tree-hollow-forming termites in eucalypt forest in the Upper Blue Mountains, New South Wales, following seven years of extreme weather and mega-fires. Tree hollows are a critical denning and breeding resource for many fauna species. The general abundance of termites in this cool temperate area was low, with at least 65% of large eucalypts having no internal hollows and thus never having supported termites. There was evidence of a recent decline of at least 55% in the number of trees being actively worked by termites, based on the number of trees with no termites present but evidence of termite activity within the last five years. Despite this decline, hollow-forming termites were still present in at least 61% of the survey sites. Recovery could be expected to occur given adequate time and stable conditions. However, the increasing pace of climate change may not allow it. In this paper, we draw attention to the importance of hollow-forming termites and the existential threat that they face under on-going climate change. We hope that it will prompt more interest and research of this issue.
de Oliveira Silva et al. (2016) model beef production in the Brazilian Cerrado, and conclude that – if accompanied by tight deforestation control – increasing production could lower emissions by incentivising better pasture management. While their analysis is valuable in identifying the conditions under which increasing meat consumption could be compatible with reducing greenhouse gas emissions, we believe that there is little chance of such conditions occurring in practice. Overall, increasing beef consumption and production is unlikely to be an effective lever for reducing emissions, and is more likely to exacerbate deforestation. The analysis by de Oliveira Silva et al. shows that reduced emissions are only possible if clearance of savannas and forests is halted almost completely. However, even if the Forest Code is implemented perfectly, ~40 million hectares of native vegetation remain legally available for conversion to pasture in the Cerrado (Soares-Filho et al., 2014). Halting deforestation on these lands would require a degree of political determination, legislative change and effective enforcement beyond even that achieved in the Amazon. Even in the 9% of the Cerrado with formal protection, deforestation has only been reduced, not eliminated (Carranza et al., 2014). According to de Oliveira Silva et al., there was zero net deforestation for pasture between 2006 and 2015 (Table S3). However, there are two reasons to be sceptical that pasture has not replaced native vegetation during that time. First, it is difficult to distinguish pasture from native Cerrado vegetation using satellite data (Spera et al., 2016). Second, net change is not the same as gross change. Cropland area in the Cerrado has doubled since 2003, at the expense of both pasture and native vegetation (Spera et al., 2016). Considering both cropland expansion and the goal of ending deforestation, net reductions in pasture area are needed to avoid further displacement of pasture into native vegetation. de Oliveira Silva et al. present no evidence to support their assumption that higher beef production would result in more carbon captured in pastures. While higher profits might allow investment in pasture restoration, higher stocking rates can instead result in reduced soil organic carbon stocks (Navarrete et al., 2016). Improved pasture management, if implemented, could increase grassland productivity, but this increased productivity will only translate into increased carbon storage if it outpaces the higher amount of carbon removed in the form of beef. Grazing strongly reduces the share of net primary production (NPP) that can accumulate in an ecosystem (Soussana et al., 2007), with up to 60% of above-ground dry matter ingested by livestock in intensive grazing systems (Lemaire & Chapman, 1996). For this reason, increased NPP is not a good surrogate for increased carbon storage (net biome productivity; NBP). Pasture productivity can also be increased on a shrinking pasture area without any increase in beef production. Furthermore, by treating the Cerrado as one large farm, de Oliveira Silva et al. omit important heterogeneity in how ranchers respond to beef price changes. When beef prices fall, marginally profitable farms may take land out of production or go out of business. Abandoned pasture could then revert to secondary vegetation, storing carbon in the process (Chazdon et al., 2016). This outcome is not considered, meaning the potential for reduced beef demand to promote carbon sequestration is underestimated. The study underlines the importance of controlling deforestation for reducing emissions from the agricultural sector, but other policy levers appear more promising than increasing beef production. Such levers include making access to agricultural credit conditional on achieving habitat conservation targets (Nepstad et al., 2014), incentives for forest restoration (Latawiec et al., 2015) and programmes of support to ranchers to improve pasture management (Strassburg et al., 2014). A shift away from meat-rich diets would reduce the amount of land needed for food production, leaving more scope for conserving native vegetation (Erb et al., 2016). More emissions could be captured if cattle herds are reduced, and if land-sparing policies are developed to promote improved pasture management on a smaller area, coupled with protection and restoration of native vegetation (Cohn et al., 2014; Lamb et al., 2016). Taking action to reduce beef demand and cattle herds would help not only to reduce emissions, but also to safeguard the soils, water and biodiversity of the Cerrado. BP is supported by a grant from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) through the Brazilian Science without Borders programme (number 88881.068115/2014-01). He thanks Luciana Leite de Araújo for suggesting the topic of this letter.
Abstract Biomass feedstocks are growing in importance due to their ability to serve as a renewable alternative to fossil fuels for large scale energy generation, with bioenergy projected to be a growing part of the UK's energy mix. Combined with technologies such as carbon capture and storage, sustainable bioenergy has the potential to produce negative emissions with including counterbalancing residual emissions. This paper presents a systematic review of the sustainability impacts of wood biomass (forestry/SRC) and Miscanthus , which are grown as energy fuels, comparing the three key indicators of sustainability: soil organic carbon sequestration rates, biodiversity, and water use efficiency (WUE). Analysis has shown significant influence from primary soil composition ( p < 0.001) and previous land use ( p < 0.001) on soil organic carbon sequestration rates following conversion to biomass feedstock production. Conversion from arable to forestry can have positive rates of sequestration of 1.4 ± 0.3 Mg C ha −1 year −1 on mineral soils, while similar conversions on a highly organic soils can lead to losses of −25 Mg C ha −1 year −1 . This indicates a strong need for careful site selection for future forestry plantations. Miscanthus showed no preference under mineral or organic soils for carbon sequestration rate. Biodiversity at different trophic scales is impacted differently by biomass feedstock production. No significant impact on invertebrates was demonstrated between feedstocks but there is a significant difference between crops ( p < 0.001) for vertebrates at higher trophic levels. A limited dataset was collected for WUE from the review, but analysis showed comparable WUE rates for Miscanthus and short rotation coppice, while forestry had significantly lower ( p < 0.001) WUE. With global temperatures increasing and changes to climate, water stress is likely to increase. WUE will play an important role in the considerations dfor long term biomass feedstock planning and sourcing.
The monitoring, reporting and verification (MRV) of soil organic carbon (SOC) sequestration following management changes is complex due to the multitude of influencing factors related to ecosystem processes but also due to (socio-)economic or legal requirements. Several protocols for MRV applications have been published. In this chapter we will provide an overview about available systems and their advantages and limitations. There is a wide range of options to quantify SOC changes, but most of these options have limitations. Field measurements, including periodic on site measurements, short-term experiments and long-term monitoring are time consuming, cost and labour intensive. On the other hand modelling, and/or remote sensing approaches are associated with uncertainty, and/or data demand. Therefore, an effective MRV application should be a combination of different approaches. This chapter will discuss the different aspects, which will be picked up in the other chapters of this section that will present more details on quantification options.
