A neighborhood approach to the biogeography of Puerto Rican trees

Collaborators: Bob Muscarella,  Aarhus University, Denmark.

Funding: NSF – DEB – Population and Community Ecology.

The geographic distributions of tree species reflects both physical (e.g., geology, climate) and local processes (e.g., competition, herbivory). These factors do not act independently. For example, the strength of competition among trees may be stronger in low fertility soils. However, only a few studies have examined the simultaneous effects of physical factors and local processes on tree growth and survival. Such synthesis is central to predicting tree species responses to environmental change. This is a critical issue in tropical forests because these ecosystems are experiencing rapid environmental change and play a key role in regulating global climate.

 We are developing a novel spatially-explicit neighborhood approach to disentangle local effects of environmental heterogeneity and biotic interactions on tree growth and survival across Puerto Rico while accounting for individual trait variation. The island has high tree diversity, marked environmental and climate gradients, and an extensive amount of existing data, making this an ideal site for this research. To do so, we will couple (a) tree trait measurements across species ranges traits, including traits related to water use strategies, (b) trait-based neighborhood models of tree growth and survival derived from data collected in 24 mapped plots, and (c) generalized joint attribute models that characterize species distributions with respect to regional environmental gradients using herbaria collections.

Figure 1. Distribution of the study sites in Puerto Rico.

Figure 2. Location of two distinct study sites in Puerto Rico: Guánica Dry Forest and Luquillo Rainforest.

Figure 3. Functional traits of leaves.