Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh
Dissertation (Ph.D.) University of Alaska Fairbanks, 2001 Herbivores influence, and often regulate energy flow. I investigated interactions between herbivory and the foods on which geese rely while nesting and rearing their broods on the Yukon-Kuskokwim Delta in southwestern Alaska. In a captive Cac...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
2001
|
Subjects: | |
Online Access: | http://hdl.handle.net/11122/5033 |
id |
ftunivalaska:oai:scholarworks.alaska.edu:11122/5033 |
---|---|
record_format |
openpolar |
spelling |
ftunivalaska:oai:scholarworks.alaska.edu:11122/5033 2023-05-15T15:16:41+02:00 Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh Person, Brian Thomas 2001-12 http://hdl.handle.net/11122/5033 en_US eng http://hdl.handle.net/11122/5033 Department of Biology and Wildlife Dissertation phd 2001 ftunivalaska 2023-02-23T21:36:20Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2001 Herbivores influence, and often regulate energy flow. I investigated interactions between herbivory and the foods on which geese rely while nesting and rearing their broods on the Yukon-Kuskokwim Delta in southwestern Alaska. In a captive Cackling Canada gosling (Branta Canadensis minima) experiment I decoupled the effects of seasonal declines in forage quality and availability on gosling development. An 11% decline in forage quality translated to goslings that were structurally smaller and 100 g lighter at 31 days of age. Forage availability had similar effects on gosling size, and the combined magnitude of these effects are similar to those observed in wild populations. I manipulated within-season grazing history of 'Carex subspathacea' swards within brood-rearing areas used by Black Brant geese (Branta bernicla nigricans). Spatial variation in forage quality and availability exceeded seasonal variation. Brant consumed over 95% of the annual aboveground production of these swards without any short- or apparent long-term effects on aboveground growth. Adding grazing pressure to 'C. ramenskii, ' or removing grazing pressure from 'C. subspathacea, ' resulted in a bi-directional shift in the morphology and nutritional characteristics of these sedges. The areal extent of 'C. subspathacea' increased 2 to 8% of the Tutakoke landscape with a concomitant decrease in 'C. ramenskii' meadows between 1991-1998. Brant have been increasing the carrying capacity of the Tutakoke River colony following a population decline in the early 1980's. The population has increased beginning in 1988, yet remains below historic numbers. Density-dependent effects on gosling growth accompanied the population increase initially. However, gosling mass has increased over the past decade due to herbivore-mediated increases in the areal extent of grazing lawns. Ch. 1. Cackling Canada gosling growth: separating variation in food quality from availability -- Ch. 2. Forage variation in ... Doctoral or Postdoctoral Thesis Arctic Branta bernicla Branta canadensis Kuskokwim Alaska Yukon University of Alaska: ScholarWorks@UA Arctic Brant ENVELOPE(7.105,7.105,62.917,62.917) Canada Fairbanks Yukon |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2001 Herbivores influence, and often regulate energy flow. I investigated interactions between herbivory and the foods on which geese rely while nesting and rearing their broods on the Yukon-Kuskokwim Delta in southwestern Alaska. In a captive Cackling Canada gosling (Branta Canadensis minima) experiment I decoupled the effects of seasonal declines in forage quality and availability on gosling development. An 11% decline in forage quality translated to goslings that were structurally smaller and 100 g lighter at 31 days of age. Forage availability had similar effects on gosling size, and the combined magnitude of these effects are similar to those observed in wild populations. I manipulated within-season grazing history of 'Carex subspathacea' swards within brood-rearing areas used by Black Brant geese (Branta bernicla nigricans). Spatial variation in forage quality and availability exceeded seasonal variation. Brant consumed over 95% of the annual aboveground production of these swards without any short- or apparent long-term effects on aboveground growth. Adding grazing pressure to 'C. ramenskii, ' or removing grazing pressure from 'C. subspathacea, ' resulted in a bi-directional shift in the morphology and nutritional characteristics of these sedges. The areal extent of 'C. subspathacea' increased 2 to 8% of the Tutakoke landscape with a concomitant decrease in 'C. ramenskii' meadows between 1991-1998. Brant have been increasing the carrying capacity of the Tutakoke River colony following a population decline in the early 1980's. The population has increased beginning in 1988, yet remains below historic numbers. Density-dependent effects on gosling growth accompanied the population increase initially. However, gosling mass has increased over the past decade due to herbivore-mediated increases in the areal extent of grazing lawns. Ch. 1. Cackling Canada gosling growth: separating variation in food quality from availability -- Ch. 2. Forage variation in ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Person, Brian Thomas |
spellingShingle |
Person, Brian Thomas Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
author_facet |
Person, Brian Thomas |
author_sort |
Person, Brian Thomas |
title |
Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
title_short |
Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
title_full |
Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
title_fullStr |
Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
title_full_unstemmed |
Herbivore-mediated effects on ecosystem processes in a near-Arctic salt marsh |
title_sort |
herbivore-mediated effects on ecosystem processes in a near-arctic salt marsh |
publishDate |
2001 |
url |
http://hdl.handle.net/11122/5033 |
long_lat |
ENVELOPE(7.105,7.105,62.917,62.917) |
geographic |
Arctic Brant Canada Fairbanks Yukon |
geographic_facet |
Arctic Brant Canada Fairbanks Yukon |
genre |
Arctic Branta bernicla Branta canadensis Kuskokwim Alaska Yukon |
genre_facet |
Arctic Branta bernicla Branta canadensis Kuskokwim Alaska Yukon |
op_relation |
http://hdl.handle.net/11122/5033 Department of Biology and Wildlife |
_version_ |
1766346977413431296 |