"Biocapacity refers to the capacity of a given biologically productive area to generate an on-going supply of renewable resources and to absorb its spillover wastes. Unsustainability occurs if the area’s ecological footprint exceeds its biocapacity." (https://www.greenfacts.org/glossary/abc/biocapacity.htm)
2. James Quilligan et al.:
"Biocapacity is the dynamic balance point between the number of organisms within a given area and the amount of resources that are needed to support them within this area. Thus, agricultural biocapacity indicates the degree to which the population of a bioregion is greater or lesser than the food that is available from the bioregion to feed it.
By combining scientific reason with place-based knowledge, culture and history, biocapacity provides a baseline for sustainability by showing how different interventions will effect different outcomes. This allows communities to develop evidence-based guidelines for organizing their own resource sufficiency while regenerating the ecology of their life-places.
To understand the sustainability of the region’s agriculture, we examine the biophysical relationship between the arable land available in an area and the aggregate needs of the population within that area. To do this, we use two measures for food value: biomass (pounds) and bioenergy (calories). This enables us to look at agricultural resources in terms of the thermodynamic throughput between the thresholds of food accessible in a bioregion and the allocations of food needed to support the people who live there.
In this way, the metrics of biocapacity allow us to bridge a human community with the bioregion which provides its material support. This is not something that most of us think about. We rarely consider how the human population interacts with the resource system which sustains it." (https://wiki.p2pfoundation.net/Agricultural_Sustainability_for_Bioregionalism_in_the_San_Francisco_Bay_Watershed)