Assessing the pressure of agriculture and forestry over carbon flows in South-Central Chile applying the Human Appropriation of Net Primary Production framework

Abstract

The rising demand for raw materials to meet societal needs has disrupted critical carbon flows that are essential for maintaining the balance of natural ecosystems. The Human Appropriation of Net Primary Production (HANPP) provides a framework to estimate the amount of biomass used by human societies relative to the total biomass available in natural ecosystems. To quantify HANPP, it is necessary to assess two key components: the carbon extracted for food and fiber (NPP_harv) and the carbon lost due to land-use changes (NPP_lluc). This research aims to evaluate the pressure exerted by agricultural and forestry activities on the carbon flows of terrestrial ecosystems in South-Central Chile at the communal level, applying the HANPP framework. Additionally, the study estimates the share of HANPP that is lost to ecosystems and remains unavailable for human use, offering insights into the carbon flows not recovered by the socio-ecological system. The results reveal that agricultural communes exhibit the highest NPP_lluc values, indicating reduced carbon fixation, whereas forestry communes achieve higher NPP_harv values due to increased carbon yields. Overall, the average value of HANPP during agricultural and forestry activity in South-Central Chile was calculated at 82.1 %, with 62.0 % attributed to NPP_harv and 20.1 % to NPP_lluc. Notably, 26.7 % of the total HANPP is unavailable as an energy source for both humans and ecosystems. The findings from this study are intended to support public policies focused on promoting sustainable resource management and mitigating the environmental impacts of human activities.