How does site invadedness relate to funding for invasive plant treatment?

Background/Question/Methods

Active land management of conservation properties is necessary to maintain the species of interest since broad ecological processes are often inhibited by landscape fragmentation. Management costs can be significant, yet they are difficult to account for in long term conservation planning. For example, invasive species management is a primary and expensive activity on many conservation sites, but expected invasion intensity is rarely known. Predicting this invadedess is a prerequisite to estimating long term management costs.

Here we use a multiple regression framework to model invasion intensity across 30 plant species and 365 conservation lands in Florida. Site level predictor variables included parcel size, site elevation, frost days per year, road density, and nearby house density. We then used budget allocations for invasive species treatment from a ten year period to determine the relationship between investment in invasive species management and invadedness for a subset of the sites.

Results/Conclusions

Site invadedness was predicted by site area and the number of surrounding households.  However, the explained variation was dependent on the type of species distribution data used. Cumulative funding investment at a site was also predicted by the number of surrounding households and the area of the site. Despite similar factors driving funding level and invasion, management costs are not correlated with invadedness. This suggests that an estimation of long term costs based on current funding may be an underestimate of needs.