ERA

Download the full-sized PDF of A multi-scale test of the forage maturation hypothesis in a partially migratory ungulate populationDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3SQ8QH91

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Biological Sciences, Department of

Collections

This file is in the following collections:

Journal Articles (Biological Sciences)

A multi-scale test of the forage maturation hypothesis in a partially migratory ungulate population Open Access

Descriptions

Author or creator
Hebblewhite, M.
Merrill, E.
McDermid, G.
Additional contributors
Subject/Keyword
Rocky Mountains
Forage
Cervus elaphus
NDVI
Elk
Migration
Selection
Canada
Alberta
Forage maturation
Partial migration
Phenology
Digestibility of forage
MODIS
Forage quality
Type of item
Journal Article (Published)
Language
English
Place
Time
Description
The forage maturation hypothesis (FMH) proposes that ungulate migration is driven by selection for high forage quality. Because quality declines with plant maturation, but intake declines at low biomass, ungulates are predicted to select for intermediate forage biomass to maximize energy intake by following phenological gradients during the growing season. We tested the FMH in the Canadian Rocky Mountains by comparing forage availability and selection by both migrant and nonmigratory resident elk (Cervus elaphus) during three growing seasons from 2002-2004. First, we confirmed that the expected trade-off between forage quality and quantity occurred across vegetation communities. Next, we modeled forage biomass and phenology during the growing season by combining ground and remote-sensing approaches. The growing season started 2.2 days earlier every 1 km east of the continental divide, was delayed by 50 days for every 1000-m increase in elevation, and occurred 8 days earlier on south aspects. Migrant and resident selection for forage biomass was then compared across three spatial scales (across the study area, within summer home ranges, and along movement paths) using VHF and GPS telemetry locations from 119 female elk. Migrant home ranges occurred closer to the continental divide in areas of higher topographical diversity, resulting in migrants consistently selecting for intermediate biomass at the two largest scales, but not at the. nest scale along movement paths. In contrast, residents selected maximum forage biomass across all spatial scales. To evaluate the consequences of selection, we compared exposure at telemetry locations of migrant and resident elk to expected forage biomass and digestibility. The expected digestibility for migrant elk in summer was 6.5% higher than for residents, which was corroborated with higher fecal nitrogen levels for migrants. The observed differences in digestibility should increase migrant elk body mass, pregnancy rates, and adult and calf survival rates. Whether bottom-up effects of improved forage quality are realized will ultimately depend on trade-offs between forage and predation. Nevertheless, this study provides comprehensive evidence that montane ungulate migration leads to greater access to higher-quality forage relative to nonmigratory congeners, as predicted by the forage maturation hypothesis, resulting primarily from large-scale selection patterns.
Date created
2008
DOI
doi:10.7939/R3SQ8QH91
License information
Rights
© 2008 Ecological Society of America. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.
Citation for previous publication
Hebblewhite, M., Merrill, E., & McDermid, G. (2008). A multi-scale test of the forage maturation hypothesis in a partially migratory ungulate population. Ecological Monographs, 78(2), 141-166. DOI: 10.1890/06-1708.1.
Source
Link to related item

File Details

Date Uploaded
Date Modified
2014-05-02T17:38:43.975+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 1459237
Last modified: 2015:10:12 13:11:22-06:00
Filename: EM_78_2008_141.pdf
Original checksum: fe6c5247feaec0cc71f3ad3694367f8a
Well formed: true
Valid: true
File title: emon-78-01-06 141..166
Page count: 26
Activity of users you follow
User Activity Date