FSD 2010 - Westcott

5th International Symposium-Workshop on Frugivores and Seed Dispersal (1985-2010)

Dave Westcott

CSIRO, Sustainable Ecosystems, PO Box 780 Atherton Qld, Australia

david.westcott(a)csiro.au

(Photo : Denise Hardesty and Dave Westcott at FSD2005. © P.-M. Forget)

Activities

In his role as a Principal Research Scientist, Tropical Landscapes, at CSIRO's Atherton Laboratory in Queensland, Dr Westcott is responsible for (1) managing the Ecosystem Function and Prediction Stream in CSIRO's Healthy Terrestrial Ecosystems theme; (2) developing new research projects and (3) leading a group of scientists and technical staff studying the ecology of tropical rainforests and landscapes. His current projects include identification and impact of invasive pests in the Wet Tropics rainforests,assowary genetics and population monitoring, biodiversity in Wet Tropics floodplains, predicting and managing invasive spread in rainforest habitats, and Flying fox ecology and management.

Abstract

Modelling dispersal in the context of plant invasions: interactions between dispersal, landscape structure and management determine the most effective management strategy

by D. Westcott and C. Fletcher

Plant invasions are increasingly being recognised as a major threat to tropical forests with massive environmental, economic and aesthetic costs. Because plant invasions are fundamentally about the movement of plant propagules through landscapes, an understanding of their dispersal ecology holds the promise of informing both our understanding of invasion processes and of improving their management. Because the shape and scale of the dispersal kernel determines the distribution of potential recruits, dispersal kernels are a major determinant of the pattern and rate of invasive spread and consequently are key to its understanding and management. While much effort has been invested into describing dispersal kernels in tropical forests, comparatively little effort has been invested into the application of this knowledge to the management of a major threat these forests. In this talk we illustrate how an understanding of dispersal can be used to predict the pattern of invasive spread at a landscape scale and can lead to dramatic improvements in the effectiveness of the management of invasive plants in tropical forest systems. Fundamental to this is the ability to predict the pattern of invasive spread. We achieve this using a mechanistic model of vertebrate dispersal kernels, empirically derived from studies of disperser movement and foraging behaviour, integrated into an individual-based, spatially-explicit simulation model of a plant population and parameterised with the life-history parameters of a major invasive species of rainforests in Australia, Miconia calvescens. Using this model we describe how environmental heterogeneity and mortality factors interact with the dispersal to determine the rate and pattern of invasive spread. These model runs simulate actual infestations and the spatial data from these real infestations are used to assess model predictions. We then use the model to examine the interaction between management and invasive spread to identify ‘rules of thumb’ for the design and conduct of management programs. The model and field results provide a clear example of the major contribution that dispersal ecology has to make to the management to a major environmental threat.

Recent references

Bradford, MG and Westcott, DA 2009. The consequences of southern cassowary (Casuarius casuarius, L.) gut passage and deposition pattern on the germination of rainforest seeds. Austral Ecology, in press.

Bradford, MG, Dennis, AJ, Westcott, DA. 2008. Diet and dietary preferences of the southern cassowary (Casuarius casuarius) in North Queensland, Australia . Biotropica, 40: 338-343.

Buckley, YM, Anderson, S, Catterall, CP, Corlett, RT, Engel, T, Gosper, CR, Nathan, R, Richardson. DM, Setter, M, Spiegel. O, Vivian-Smith. G, Voigt, FA, Weir, JES, Westcott, DA (2006) Management of plant invasions mediated by frugivore interactions. Journal of Applied Ecology 43: 848-857.

Downey , PO, Turner, PJ, Hamilton , MA , and Westcott DA (submitted). The role of birds in plant invasions and native species declines: implications for biodiversity conservation, revegetation and restoration. Biological Invasions.

Fletcher, CS and Westcott DA. 2009. Modelling weeds and people: how today’s management determines tomorrow’s infestations. Plant Protection Quarterly, 24: 99-100.

Fox, S, Luly, J, Mitchell, C, Maclean, J, Westcott, DA (2008). Demographic indications of decline in the spectacled flying-fox (Pteropus conspicillatus) on the Atherton Tablelands of northern Queensland . Wildlife Research 35: 417-425.

Hill, R, Williams, KJ, Pert, PL, Robinson, CJ, Dale, AP, Westcott, DA, Grace, R & O'Malley, T. (in press). Effective Community-based natural resource management for biodiversity conservation in Australia ’s tropical rainforests. Environmental Conservation.

Murphy HT, Hardesty BD, Fletcher CS, Metcalfe DJ, Westcott DA, Brooks SJ. 2008. Predicting dispersal and recruitment of Miconia calvescens (Melastomaceae) in Australian tropical rainforests. Biological Invasions. 10: 925-936.

Murphy HT, Metcalfe DJ, Bradford MG, Ford AF, Galway KE, Sydes TA, Westcott DA. 2008. Recruitment dynamics of invasive species in rainforest habitats following Cyclone Larry. Austral Ecology. 33: 495-502.

Parsons, J, Cairns , A, Johnson, C, Robson, S, Shilton, LA & Westcott, DA. 2007. Bats as dispersers of bryophytes and micro-organisms: a novel discovery. Oecologia 152:112-114.

Parsons, J, Cairns , A, Johnson, C, Robson, S, Shilton, LA & Westcott, DA. 2006. Diet variation in Spectacled Flying Foxes (Pteropus conspicillatus) in the Wet Tropics of Australia. Australian Journal of Zoology 54: 417-428.

Shilton , LA , Latch PJ, McKeown, A, Pert, P, Westcott DA (2008). Landscape-scale redistribution of a highly mobile threatened species, Pteropus conspicillatus (Chiroptera, Pteropodidae), in response to Tropical Cyclone Larry. Austral Ecology 33:549-561

Westcott DA and Fletcher, CS. 2009. Using dispersal data to model invasive spread and management effectiveness. Plant Protection Quarterly, 24: 98-99.

Westcott, DA, Dennis AJ, Bradford , MG, McKeown, A, Harrington, GN. 2008. Seed dispersal processes in Australia ’s Wet Tropics rainforests. Pp 210-223 in, Stork N and Turton S (eds), Living in a dynamic tropical forest landscape. Blackwell Publishing, Malden.

Westcott, DA, Setter, M, Bradford MG, Setter, S, McKeown, A. 2008. Dispersal of pond apple seeds by the southern cassowary: ecological interactions between a threatened and a threatening species. Diversity and Distributions 14: 432-439.

FSD 2010 - Westcott

Dave Westcott

Activities

Abstract

Recent references

Other FSD presentations