Tree mode of death and mortality risk factors across Amazon forests.

The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted-modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth-survival trade-off in driving tropical tree mortality.

Influence of livelihood assets, experienced shocks and perceived risks on smallholder coffee farming practices in Peru.

Smallholder farmers might adopt different farming practices to cope with multiple stressors depending on their livelihood assets, and with varying environmental and economic outcomes. Ongoing global change is triggering stronger and different stressors that threaten conventional farming practices; however, this could be resolved if livelihood assets that drive decision making are actionable and thus can be modified. This study assessed the influence of farmers' livelihood assets, risk perception, and shocks on the choice of non-conventional farming practices for smallholder coffee farmers in San Martín, Peru. Using household survey data, we collected data on 162 coffee plantations along an elevation gradient. We operationalized the sustainable livelihoods framework for the adoption of shade and input coffee farming strategies and explored farmers' motives to change them. Despite associated high risks with pest and disease pressure, coffee price volatility and climate change, these risks did not explain the current shade and input farming strategies. While in the past five years, farmers adapted shade and input management in response to pest and disease and climate change pressures, these occurred in diverging directions: we found higher human and social assets associated with higher shade levels, and a trend for higher physical and financial assets associated with higher input use. These findings illustrate that two main factors affect decisions on farming practices related to shade and input management and they relate to different livelihood capitals. This suggests a potential for conflicting decision-making, push-and-pulling decisions in different directions. Further the disconnect between livelihood assets and perceptions suggests that perception of risk and shocks might not be sufficient to motivate decision making under changing conditions. Such insights in decision-making typologies and drivers can inform the development of farming practices that enhance resilience and sustainability of smallholder coffee production in Peru and elsewhere in the tropics.