RAPID: Hurricane Maria: ASSESSING LANDSCAPE RESILIENCE TO A CHANGING DISTURBANCE REGIME

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The intensity of hurricanes is anticipated to rise with rising temperatures and individual storms can have dramatic impacts on the carbon dynamics in forests. A strong, single hurricane can convert significant amounts of living forest carbon into dead biomass, and much of that carbon will return to the atmosphere through natural decomposition and soil carbon losses. This acts as a positive feedback to a warming climate. Severe storms also change species composition making the forest vulnerable to subsequent hurricanes. The majority of studies on impacts of hurricanes on ecosystems, however, have been conducted at the plot level and over a limited range of environmental conditions. As a result, our understanding of the factors that impact forest vulnerability to hurricanes and post-storm recovery at the landscape scale is extremely limited. This research will investigate the effects of Hurricane Maria on forested landscapes in Puerto Rico using a combination of a remotely sensed satellite products, data from field plots, and mathematical models. The proposed research will generate data and knowledge essential for the development of forest management practices that are resilient to climate variability and change. Data will be made publicly available and shared with government agencies. One technician, one graduate student, and ten field volunteers will be trained in ecological research. A RAPID response is required to prevent loss of data due to vegetation decomposition and to link remote sensing data to ground observations of damage. Re-growth after storms is swift; the remote sensing signal lasts approximately 1 year following a storm, until post-storm recovery generates new leaf biomass.Hurricanes represent the dominant natural disturbance in temperate and tropical forests in coastal regions of the North Atlantic. Severe storms also favor recruitment of early successional tree species that are particularly vulnerable to subsequent hurricanes, acting as a positive feedback that exacerbates ecosystem vulnerability. The spatial distribution of wind damage across the landscape depends on storm meteorology, physical landscape heterogeneity, and the attributes of individual trees and aggregate stand structure. Disentangling the contribution of each of these factors to observed damage can be difficult because tree species differ in their vulnerability to storm damage and, at the same time, are distributed in a non-random fashion with respect to landscape factors. Understanding ecosystem vulnerability to severe storms over large spatial extents requires approaches that can tease apart the contributions of landscape and local factors. The proposed research will rely on recent advances in remote sensing tools including optical and hyperspectral images and Light Detection and Ranging to generate novel insights into the landscape and local factors that lead to spatial heterogeneity in storm impacts across broad spatial extents. Investigators will address the following questions: 1) how do landscape characteristics such as topography, slope, aspect, geology, and forest age and fragmentation influence wind damage and biomass loss after a severe hurricane; 2) what is the selective pressure of hurricane damage on forest composition; and (3) how does landscape heterogeneity influence biomass recovery?