[Longwood] Thrive as cancer cells in forests? Spatial, social, and ecological factors driving the distribution of invasive plant (Mikania micrantha) establishment and spread in a biodiversity hotspot in subtropical Nepal

Date: 

Thursday, January 10, 2019, 10:00am to 11:00am

Location: 

Warren Alpert Building, Room 563 (Longwood)

The CGA hosts the Harvard Geography Colloquium in which we invite leading academics to present cutting edge geographic research.

Abstract
Anthropogenic habitat alteration and invasive species dispersal are considered the leading drivers of biodiversity loss worldwide. Human activities create unavoidable disturbances to the natural environment and irreversible impacts to the overall ecosystems. We examine the effects of current human land use (household and forest management activities), historic land degradation, plant community composition, and current natural and anthropogenic disturbances on invasive plant establishment and abundance in two forest types in the buffer zone of Chitwan National Park, Nepal. This research addresses the human-caused and biophysical characteristics of forest types that contribute to invasion of Mikania micrantha, the dominant invader in Western Chitwan Valley. We evaluated canopy cover and a measure of plant community richness at the plot level by ecological survey in locally governed community forests. Remotely sensed measures of enhance vegetation index (EVI) were identified at the plot level from 1988 to 2015 as a proxy for historical disturbance. We collected social survey data by innovative tablet social survey at the household level and community forest management committee level for all catchment areas surrounding the community forests. The distribution of this dominant invader could be influenced by different ecological, social, and spatial drivers and may occupy sites with unique land use histories. We found ecological characteristics to be the dominant driver for Mikania establishment and growth. However, when household variables are modeled separately, thatch collection and recreational activities are significant predictors of Mikania establishment and abundance. The multiscale geographically weighted regression (MGWR) results further confirm the strong influence from ecological variables, and the results also demonstrate how spatial factors influence the overall understanding of the Mikania establishment and abundance. Determining the factors that contribute to invasive plant establishment and spread in these forests will enhance our understanding of the invasion process and help to identify social and ecological characteristics of forests under threat of future invasion.


About the Speaker
Qunshan Zhao is currently a postdoctoral research associate at Spatial Analysis Research Center (SPARC: https://sgsup.asu.edu/SPARC) and Knowledge Exchange for Resilience (KER: https://resilience.asu.edu/) at Arizona State University. Qunshan’s interdisciplinary research agenda focuses on using GIScience, remote sensing, and spatial analysis to solve emerging environmental and societal problems in the urban environment. He has participated multiple federal and philanthropic funded research projects from NSF, NIH, NASA, and Virginia G. Piper Charitable Trust. He received the J. Warren Nystrom Award (the Most Outstanding Research Paper Based Upon a Recent Dissertation) from American Association of Geographers (AAG) at April 2018, and Dissertation Research Grant from AAG at April 2017. He currently serves as the board member of Spatial Analysis and Modeling (SAM) specialty group at AAG.