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Utah State University (2012)

Avian Response to Post Wildland Fire Reseeding Treatments in Great Basin Shrubsteppe

Brewerton Adam B.

Titre : Avian Response to Post Wildland Fire Reseeding Treatments in Great Basin Shrubsteppe

Auteur : Brewerton Adam B.

Université de soutenance : Utah State University

Grade : Master of Science 2012

Résumé
We investigated the effects of different fire restoration treatments on five shrubsteppe bird species in the Great Basin of central Utah. Sagebrush communities and the associated avifauna are under particular threat due to changing fire regimes. Although fires are locally destructive, it is hypothesized that they improve habitat by increasing landscape-level heterogeneity. As long as fire follows a historic fire regime, the plant and animal communities can usually recover. However, fires can and often do burn outside of the normal regime. The Milford Flat Fire, which occurred in west-central Utah, was the largest wildfire recorded in the Great Basin. Considered catastrophic, concern existed that natural recovery of sagebrush and its avifauna would be unlikely. To prevent this, vegetation reseeding treatments were applied immediately post-fire. These treatments included two seed mix types, with or without a shrub component, and three mechanical applications, drill seeding, aerial seeding followed by chaining, and aerial seeding only. We surveyed the avian community in the different treatment types and in untreated areas within the fire using line transect distance sampling methods. Using a space for time substitution, we sampled nearby unburned areas as reference to represent pre-fire conditions. We hypothesized that the treatment areas would be more similar to the reference than the untreated areas, and that the treatments would all have similar effects. We found some effect on the presence and extirpation of the birds at the guild and overall bird level. We found no significant effect from the treatments on the five study species at the species level, and no effects on bird densities. The effects of the restoration treatments were overshadowed by the effect of the fire on changing the habitat, namely, the density of sagebrush. We saw a pattern of birds responding to the removal or survival of sagebrush and the treatments were insufficient in affecting a short term response.

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Page publiée le 21 octobre 2012, mise à jour le 12 juillet 2018