Landscape connectivity and seed dispersal characteristics inform the best management strategy for exotic plants

Abstract

Exotic plant invasions have triggered environmental and economic problems throughout the world. Our ability to manage these invasions is hindered by the difficulty of predicting spread in fragmented landscapes. Because the spatial pattern of invasions depends on the dispersal characteristics of the invasive species and the configuration of suitable habitat within the landscape, a universal management strategy is unlikely to succeed for any particular species. We suggest that the most effective management strategy may be an adaptive one that shifts from local control to landscape management depending on the specific invader and landscape. In particular, we addressed the question of where management activities should be focused to minimize spread of the invading species. By simulating an invasion across a real landscape (Antietam National Battlefield in Maryland, USA), we examined the importance of patch size and connectivity to management success. We found that the best management strategy depended on the dispersal characteristics of the exotic species. Species with a high probability of random long-distance dispersal were best managed by focusing on the largest patches, while species with a lower probability of random long-distance dispersal were best managed by considering landscape configuration and connectivity of the patches. Connectivity metrics from network analysis were useful for identifying the most effective places to focus management efforts. These results provide insight into invasion patterns of various species and suggest a general rule for managers in National Parks and other places where invasive species are a concern.

Implications of newly-formed seed-dispersal mutualisms between birds and introduced plants in northern California, USA

“…This result is supported by recent modeling of the role of patch size in invasive species control when long-distance dispersal events are regular occurrences (Minor and Gardner 2011). My conclusion that number of fruiting trees is important also complements previous data showing that the total number of fruits in the neighborhood is significantly and positively related to greater levels of bird foraging on exotic species (Sargent 1990).…”

Consistency in fruit preferences across the geographical range of the frugivorous bats Artibeus , Carollia and Sturnira (Chiroptera)

“…This is probably related to its phylogenetic proximity with the family Moraceae (Zhang et al, 2011), the family that includes Some of the species (Carica papaya L. and Syzygium jambos (L.) Alston, for example) consumed by these bats are exotic and their consumption and subsequent dispersion may impact native fl ora (Minor & Gardner, 2011;Voigt et al, 2011). Bats seem to respond positively to fruit availability (Lobova et al, 2009), reinforcing the need for planning in both urban and rural areas to protect native fl ora from invasions (Barros et al, 2006).…”

Spatio-temporal patterns of colonization and expansion of Retama monosperma on developing coastal dunes

“…However, this is not a viable option as this is a key species in Mediterranean ecosystems (Moreno et al 2007). For this reason, management must be directed towards the design of long term plans for the reduction in density of the colonized zones and, as point out by Minor and Gardner (2011), through the control and monitoring of zones susceptible to R. monosperma establishment in order to stop or slow the expansion process.…”