Using spatially-explicit, time-dependent analysis to understand how social factors influence biological invasion

Authors: NIEMIEC, REBECCA - Stanford University; ASNER, GREGORY - Carnegie Institute - Stanford; GAERTNER, JULIE - University Of Hawaii; BRODRICK, PHIL - Carnegie Institute - Stanford; VAUGHN, NICK - Carnegie Institute - Stanford; HECKLER, JOSEPH - Carnegie Institute - Stanford; HUGHES, FLINT - Us Forest Service (FS); Keith, Lisa; Matsumoto Brower, Tracie

Submitted to: Conservation Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2019
Publication Date: 8/16/2019
Citation: Niemiec, R., Asner, G., Gaertner, J., Brodrick, P., Vaughn, N., Heckler, J., Hughes, F., Keith, L.M., Matsumoto Brower, T.K. 2019. Using spatially-explicit, time-dependent analysis to understand how social factors influence biological invasion. Conservation Biology. 34(2):505-514. https://doi.org/10.1111/cobi.13409.
DOI: https://doi.org/10.1111/cobi.13409

Interpretive Summary: A study was conducted to better understand the socio-ecological factors driving the distribution of invasive species. Land ownership, land use, ecological, and environmental factors were examined to assess how these factors affect changes in distributions of Falcataria moluccana, a fast-growing, nitrogen fixing, invasive non-native canopy tree, in Hawaii.

Technical Abstract: Stopping the spread of invasive species requires an understanding of socio-ecological factors driving their distribution. In human-dominated landscapes, invader distributions may be influenced by land ownership, land use, ecological, and environmental factors. We examined how these factors affect changes in distributions of Falcataria moluccana, a fast-growing, nitrogen fixing, invasive non-native canopy tree, in Hawaii. Due to a tropical storm and resulting management efforts undertaken during our 7-year study period, net decreases in F. moluccana cover were tenfold greater than increases. We found that land ownership influenced reactionary management, as evidenced by the fact that mean rates of F. moluccana canopy decrease varied substantially (66-100%) by land ownership characteristics. Decreases in canopy cover were greatest on lands with high-value buildings, owned by large private corporations, with homeowners who filed for property tax exemption, and with relatively low invasive species cover at the first study time-point. In contrast, canopy cover increases were consistent across land ownership and land use types. Findings suggest that landowners were more reactionary than proactive in their interactions with this invasive species, resulting in an increase in F. moluccana cover even on properties whose landowners engaged in substantial reactive management. Our findings suggest that policies are needed to motivate effective proactive control efforts.