Chris FreeApril 16th 2010Research Symposium

Valuable timber species Workable, durable, beautiful Decorative woodwork, furniture, etc Single tree - $20,000, $1800 m-3

Vulnerable to exploitation Natural range – rapid anthropogenic land

conversion Life history - low density, secondary colonizer,

disturbance dependent seedling regeneration

Deforestation over 63% of mahoganies range Selective logging of 85-90% remaining adults

Grogan et al. 2009Grogan et al. 2009

Grogan et al. 2009

CITES Appendix II - demonstration of sustainable harvest by exporting country

Little empirical basis for evaluating sustainability of proposed regulations

Inclusion in Appendix II of the neotropical populations of Swietenia macrophylla King, (Meliaceae), including logs, sawn timber, veneer and plywood, in accordance with Article II, Paragraph 2A, of the Convention and Resolution Conference 9.24, Annex 2A. The objective of this listing is to promote sustainable management of S. macrophylla in order to help ensure its further conservation and trade (CITES 2002).

Verwer et al. (2009), Grogan et al. (2009), Grogan and Landis (in prep) – spatially implicit matrix based and individual based modeling strategies No density-dependence - requires spatially

explicit approach

Grogan and Landis (in prep)

Population size/density modifies population vital rates (recruitment, growth, mortality) Competition, predation, pathogens, disease Janzen-Connell Model: distant and/or density

responsive enemies cause increased mortality of progeny near parent forcing spacing of conspecifics

Distant- and density-dependent interactions observed in big-leaf mahogany populations Leaf herbivory by specialist moth caterpillar

▪ Increased defoliation and seed predation▪ Decreased growth and recruitment success

Norghauer et al. 2006a

The purpose of my project is to examine the population-level consequences of density-dependence on big-leaf mahogany Develop a more robust population growth model Assess applicability of Janzen-Connell predictions

A spatially explicit model developed using NetLogo language and interface

Parameterized using the field data of Grogan and Landis (in prep) and Norghauer (2006a,b) 204 ha 100% inventoried field site in Pará, Brazil Experimental exclosures in Pará, Brazil Disturbance, growth, mortality, reproduction

Convention on International Trade in Endangered Species (CITES). 2002. Consideration Of Proposals For Amendment Of Appendix I And II: Swietenia macrophylla. Prop.12.50. [http://www.cites.org/eng/cop/12/prop/index.shtml accessed 14 March 2010].

Grogan, J., and Landis, R.M. 2010. Mahogany population dynamics in Brazil and implications for international trade. Forthcoming.

Grogan, J., Blundell, A.G., Landis, R.M., Youatt, A., Gullison, R.E., Martinez, M., Kometter, R., Lentini, M., and Rice, R.E. 2009. Over-harvesting driven by consumer demand leads to population decline: big-leaf mahogany in South America. Conservation Letters 3: 12-20.

Norghauer, J.M., Malcolm, J.R., and Zimmerman, B.L. 2006. Juvenile mortality and attacks by a specialist herbivore increase with conspecific adult basal area of Amazonian Swietenia macrophylla (Meliaceae). Journal of Tropical Ecology 22: 451-460.

Verwer, C., Peña-Claros, M., van der Staak, D., Ohlson-Kiehn, K., and Sterck, F.J. 2008. Silviculture enhances the recovery of overexploited mahogany Swietenia macrophylla. Journal of Applied Ecology 45: 1770-1779.