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Understanding changes in carbon sequestration due to land conversion is key for elucidating the true potential of biofuel landscapes to provide climate regulation ecosystem services. In this study, we focus on the two most promoted biofuel crops in southern Africa, Jatropha and sugarcane, to analyse the land use change effects and associated carbon impacts of growing biofuel crops in five study sites in Mozambique, Malawi and Swaziland.We found that, considering a 20-year cycle, carbon stocks in aboveground biomass are higher for sugarcane than for Jatropha. However, as soil organic carbon (SOC) is generally the main carbon pool, total carbon stocks (considering biomass and soil) will highly depend on SOC. Our results show that, in our study sites, sugarcane replaced land uses with low carbon stocks (low-density forest and agriculture), and as a result carbon gains occurred due to land use change. In the Jatropha projects, carbon gains are observed in the smallholder scheme as agricultural land was converted to Jatropha, but carbon debts occurred in the Jatropha plantation as high-density forest was cleared to grow this feedstock. Finally we show that, if a plantation of sugarcane or Jatropha is envisioned to be located in the studied regions, more forested land could potentially be converted into sugarcane (30-44% of forest) than into Jatropha (24-32%), without creating carbon debts due to land conversion. To our knowledge, this is the first comparative study of the carbon impacts of land use change of the main biofuel crops in southern Africa.

Earwigs are usually considered pest predators in orchards. Because of its worldwide distribution, most research on earwigs focuses on the European earwig Forficula auricularia Linnaeus (Insecta: Dermaptera: Forficulidae). However, very little is known of this species in Mediterranean citrus orchards. Earwigs and aphids were collected monthly during 5 years (2006–2010) from citrus canopies. Two species of earwigs were found: F. auricularia and Forficula pubescens Gené (=Guanchia pubescens), with the latter seldom cited in the literature. The goals of this study were (i) to document the abundance of these two earwig species in Mediterranean citrus canopies; (ii) to determine whether they are positively or negatively associated with each other, or randomly distributed; (iii) to measure the interannual variation of the abundance of both species during a 5‐year period and (iv) to evaluate the potential role of earwigs as pest predators in citrus canopies. As compared to colder regions, F. auricularia active period in citrus canopies in our study site lasted longer. Both species co‐occurred randomly in canopies. In 2006, both species showed approximately the same abundance, but in 2010, F. pubescens abundance in canopies was 28 times greater than that of F. auricularia. The potential role of earwigs as pest predators is higher in the Mediterranean than in other colder regions, because of the longer active period. F. auricularia is a sedentary generalist predator, already present in citrus canopies at the onset of most pest outbreaks, while F. pubescens arrived later to the canopies, but most likely was abundant enough to contribute in the control of citrus pests.