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Person

Alexandra Houston

Biologist
Email: ahouston@usgs.gov
Office Phone: 619-225-6454
Fax: 619-225-6436
ORCID: 0000-0002-8599-8265

Location
4165 Spruance Road
Suite 200
San Diego , CA 92101
US
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Data presented are results of surveys for California Gnatcatchers and vegetation sampling conducted in 2015 and 2016 to address two inter-related questions: (1) How have gnatcatchers and their habitat recovered in areas burned by wildfires in 2003, 2007, and 2014?, and (2) What is the current regional occupancy of gnatcatchers throughout their southern California range? Data for the post-fire study were collected in 2015 and 2016, while the regional occupancy survey was conducted in 2016. In 2015, Gnatcatcher occupancy as a function of fire history was derived from 324 points in the following fire categories: 2003-2006 (106 points), 2007-2010 (111 points), and 2011-2014 (107 points). In 2016, points representing...
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Data presented are results of surveys for California Gnatcatchers and vegetation sampling conducted in 2020 to address two inter-related questions: (1) How have gnatcatchers and their habitat recovered in areas burned by wildfires in 2003, 2007, and 2014?, and (2) What is the current regional occupancy of gnatcatchers throughout their southern California range? In 2020 a fifth fire category was added (2015-2019) which changed the sample sizes for the other fire categories: 2003-2006 (102 points), 2007-2010 (106 points), 2011-2014 (95 points), 2015-2019 (25 points), unburned (96 points). All post-fire study points were in San Diego County. The regional occupancy surveys included 327 points in 2020 throughout southern...
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Data presented are results of surveys for California Gnatcatchers and vegetation sampling conducted in 2024 to address two inter-related questions: (1) How have gnatcatchers and their habitat recovered in areas burned by wildfires in 2003, 2007, and 2014, and (2) What is the current regional occupancy of gnatcatchers throughout their southern California range? In 2024 additional fire categories (2020-2023) were added as study plots burned between survey years, which resulted in new fire category sample sizes in 2024: 2003-2006 (102 points), 2007-2010 (106 points), 2011-2014 (86 points), 2015-2019 (19 points), 2020-2023 (18 points), unburned (93 points). All post-fire study points were in San Diego County. The...
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Rangewide Occupancy and Post-Fire Recovery of California Gnatcatchers in Southern California (ver. 3.0, October 2024)
This project has two goals: Goal 1: The goal of this project is to conduct a statistically rigorous study of occupancy to determine the post-fire recovery of California Gnatcatchers and coastal sage scrub vegetation with the goal of informing management before, during, and after fire. Goal 2: The goal of this project is to conduct rangewide surveys to determine California Gnatcatcher occupancy at a regional scale. Because gnatcatchers will be managed through management of coastal sage scrub rather than through species-specific actions, it is necessary to determine their current status on protected lands in southern California to understand how gnatcatcher occupancy is related to coastal sage scrub plant composition,...
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