Vegetation Changes Associated with a Population Irruption by Roosevelt Elk
Date
2014-11
Authors
Starns, Heath D.
Weckerly, Floyd W.
Ricca, Mark
Duarte, Adam
Journal Title
Journal ISSN
Volume Title
Publisher
John Wiley & Sons Ltd.
Abstract
Interactions between large herbivores and their food supply are central to the study of population dynamics. We assessed temporal and spatial patterns in meadow plant biomass over a 23-year period for meadow complexes that were spatially linked to three distinct populations of Roosevelt elk (Cervus elaphus roosevelti) in northwestern California. Our objectives were to determine whether the plant community exhibited a tolerant or resistant response when elk population growth became irruptive. Plant biomass for the three meadow complexes inhabited by the elk populations was measured using Normalized Difference Vegetation Index (NDVI), which was derived from Landsat 5 Thematic Mapper imagery. Elk populations exhibited different patterns of growth through the time series, whereby one population underwent a complete four-stage irruptive growth pattern while the other two did not. Temporal changes in NDVI for the meadow complex used by the irruptive population suggested a decline in forage biomass during the end of the dry season and a temporal decline in spatial variation of NDVI at the peak of plant biomass in May. Conversely, no such patterns were detected in the meadow complexes inhabited by the nonirruptive populations. Our findings suggest that the meadow complex used by the irruptive elk population may have undergone changes in plant community composition favoring plants that were resistant to elk grazing.
Description
Keywords
NDVI, plant traits, population regulation, remote sensing, ungulate, herbivory, Biology
Citation
Starns, H. D., Weckerly, F. W., Ricca, M. A., & Duarte, A. (2014). Vegetation changes associated with a population irruption by Roosevelt elk. Ecology and Evolution, 5(1), pp. 109–120.
Rights
Rights Holder
© 2014 The Authors.
Rights License
This work is licensed under a Creative Commons Attribution 4.0 International License.