9_biodiversity.md

title	layout	parent	nav_order	math	description
9. Biodiversity	default	Model Overview	9	katex	the biodiversity section of felix

9. Biodiversity

The biodiversity module is a simple structure representing population carrying capacity. The population is represented by global and encompassing all biomes mean species abundance ($$MSA$$). $$MSA$$ is increased by species regeneration rate ($$Spec_Regen$$) and decreased by species extinction rate ($$Spec_Extn$$). In addition, $$MSA$$ approaching species carrying capacity ($$Spec_Capa$$) limits $$Spec_Regen$$ and intensifies $$Spec_Extn$$. This process is quantified as logistic functions and based on the ratio between $$MSA$$ and $$Spec_Capa$$, and the regeneration factor and the extinction factor, respectively.

9.1 Species carrying capacity

$$Spec_Capa$$ is calculated based on reference species carrying capacity ($$Spec_Capa_Max$$), representing maximum sustained population size, and influencing factors related to fertilizers consumption ($$Imp_Fertz_on_Biodiv$$), biomass production for energy purposes ($$Imp_Biom_on_Biodiv$$), climate damage ($$Imp_CC_on_Biodiv$$) and land use change ($$Imp_Land_on_Biodiv$$).

$$ Spec_Capa(t) = Spec_Capa_Max \times Imp_Fertz_on_Biodiv(t) \times Imp_Biom_on_Biodiv(t) \times Imp_CC_on_Biodiv(t) \times Imp_Land_on_Biodiv(t) $$

(Eq. 9.1)

The four influencing factors are estimated by logistic functions. In detail, $$Imp_Fertz_on_Biodiv$$ is a logistic function of fertilizer consumption (including nitrogen, phosphate, and potash fertilizers). $$Imp_Biom_on_Biodiv$$ consists of impacts from forest agriculture biomass production, which are logistic functions of related land areas. $$Imp_CC_on_Biodiv$$ is adopted from climate impact on economy, as a logistic function of temperature change from preindustrial. $$Imp_Land_on_Biodiv$$ takes into consideration changes of agricultural land, forest land, and other land compared to their initial areas.