Visualizing the impact of climate change at upper treeline across Rocky Mountain National Park, USA
No Thumbnail Available
Authors
Meeting name
Sponsors
Date
Journal Title
Format
Thesis
Subject
Abstract
Over the past 30 years, high-elevation forests of the Southern Rocky Mountain region (SRM) have been subject to heat-induced drought stress, or hotter drought, from sharply rising temperatures coupled with lower precipitation totals. Hotter drought across this region has caused widespread tree mortality from spruce beetle outbreaks and prevented successful seedling establishment within upper treeline ecotones. Recently, spruce beetle-induced mortality has also been documented across upper treeline environments where trees of all size classes have been affected, yet the spatial extent of this throughout the SRM remains unclear. This study aims to investigate whether upper treeline environments within Rocky Mountain National Park (RMNP) have been negatively impacted by hotter drought conditions, including spruce beetle-induced mortality. Repeat photography of photos taken in 1996 combined with remote sensing techniques is used to test three hypotheses: H1) Treeline advance will be widespread throughout RMNP, H2) Spruce beetle-induced mortality will be evident at upper treeline, and H3) Satellite imagery will show widespread decrease in Normalized Difference Vegetation Index (NDVI). Results from photo pairs show that treeline advance is not widespread throughout RMNP (33 percent, n=4), but spruce beetle-induced mortality at upper treeline is evident at a majority of repeat photo sites (75 percent, n=9) -- with these conditions present together in 25 percent (n=3) of the photo sites. Remote sensing results show that the majority of spruce beetle-induced mortality within RMNP and within the photo pairs occurred between 1999 and 2014, with little change occurring between 2014 and 2023. If the current trends of hotter drought continue, these findings suggest that upper treeline dynamics within RMNP will be impacted negatively from both climate and disturbance.
Table of Contents
DOI
PubMed ID
Degree
M.A.