Smallholder farmers who grow diverse landraces in centres of crop diversity contribute to sustaining the capacity of agricultural and food systems to adapt to change by maintaining crop evolution in their fields today, thus enabling humanity to continue to have the broad genetic variation needed to adapt crops to changes tomorrow. Given this fact, the last 20 years have witnessed an ever-growing interest in on-farm conservation of crop infra-specific diversity.

We describe a bio-economic model for Nassella neesiana (Chilean needle grass) that estimates the net benefit of a containment programme for the weed in Canterbury as the difference between the cost of containment and the costs incurred over time should the weed spread within sheep and beef pastoral systems. Logistic spread is assumed with the maximum area that could be invaded (772,080 ha) determined by constraining a climate niche model for the weed to susceptible farm system types within productive land use capability classes.

Grassland ecological migration project is implemented in Northwest China as an attempt to restore the deteriorative ecosystems. People are relocated from uninhabitable areas to immigrant areas, resulting in land use changes, which would significantly impact the ecological environment. Therefore, it urgently needs quantitative evaluation and analysis of the trends of ecological change in these immigrant areas. We selected Luanjingtan, which is the largest ecological immigrant area in Alxa, Inner Mongolia, as our case.