Record Details
Greater sage-grouse reproductive ecology : linkages among habitat resources, maternal nutrition, and chick survival
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Greater sage-grouse reproductive ecology : linkages among habitat resources, maternal nutrition, and chick survival |
| Names |
Gregg, Michael A.
(creator) Crawford, John A. (advisor) |
| Date Issued | 2006-05-02 (iso8601) |
| Note | Graduation date: 2006 |
| Abstract | Greater sage-grouse (Centrocercus urophasianus) populations declined range wide during the past 50 years. Grouse populations were 2-3 times larger than the current population as recently as the early 1970's. In addition to habitat loss and fragmentation, declines were attributed habitat degradation that caused reduced productivity. Because chick survival remains the most poorly understood aspect of sage-grouse reproductive ecology and may be the single most important limiting factor for sage-grouse population growth, the purpose of my research was to obtain a better understanding of sage-grouse habitat relationships and, ultimately, the habitat factors that influence survival and recruitment of sage-grouse chicks. Because sage-grouse do not rely entirely on stored nutrients for reproduction, I hypothesized that successful sage-grouse reproduction was 1) indirectly related to habitat resources through maternal nutrition and 2) directly related to resources (i.e., food and cover) available to chicks during brood-rearing. Therefore, I collected data on diet, nutrition (protein, calcium, and phosphorus), and habitat use of pre-incubating females, and habitat use, survival, and timing and causes of mortality of chicks to 28-days post-hatch. I then constructed and simultaneously evaluated several biological hypotheses expressed as regression models to investigate direct and indirect linkages between habitat resources and chick survival. My results identified linkages among availability and consumption of high-nutrient forbs, maternal nutrition, and chick survival. I also found that chick survival was related to availability of insects at brood sites. Specifically, my results indicated hens that forb consumption by hens during March and April was positively associated with likelihood of brood production and, when coupled with high Lepidoptera availability during brood-rearing, produced the most chicks. Hence, my research underscored the importance of both maternal and chick nutrition for sage-grouse chick survival. To increase chick survival, I recommend that habitat management for sage-grouse emphasize (1) forb availability during March and April to increase the nutritional status of hens and (2) insect availability, particularly Lepidoptera, during early brood-rearing to increase chick nutrition. Additionally, increased maternal nutrition may increase likelihood of renest initiation and indirectly result in greater chick recruitment. |
| Genre | Thesis/Dissertation |
| Topic | Sage grouse -- Ecology -- Oregon |
| Identifier | http://hdl.handle.net/1957/19947 |
