Conversion, intensification, and abandonment: A human appropriation of net primary production approach to analyze historic land-use dynamics in New Zealand 1860-2005

- We present a socio-ecological long-term analysis of land-use changes in New Zealand 1860-2005.
- We quantify the Human Appropriation of Net Primary Production (HANPP).
- HANPP (sum of land conversions and harvest) fluctuates between 29 and 54%.
- Our results allow discerning four major phases in past land-use trajectories.
- Trade, livestock dynamics and land-use policies emerge as drivers of these changes.

This study presents a national level analysis of changes in land use and land cover in New Zealand from 1860 to 2005. We employ the Human Appropriation of Net Primary Production (HANPP) framework to assess land use induced impacts on ecological energy flows by accounting for socioeconomic harvest and productivity losses through land use change. By analyzing the interplay of socioeconomic dynamics, changes in land use, land use efficiency, and ecosystems we distinguish four stages of land use dynamics: 1) between 1860 and 1920 HANPP increased from 34% to 53% of the potential Net Primary Production, accompanied by low HANPP efficiency. 2) After 1920, driven by legislation that ended deforestation, HANPP declined to 32.7%, and then stagnated until 1950. 3) This was followed by a new period of growth which ended in 1980, when HANPP had reached 41%. Increased agricultural inputs resulted in increasing HANPP efficiency between 1920 and 1965, when high subsidization and land expansion caused stagnation in this trend. 4) After 1980, HANPP declined and reached 32% by 2005, reflecting efficiency improvements. We discuss these observed trajectories in the context of socio-economic dynamics such as land use policies and trade.