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The Effects of Vegetative Type, Edges, Fire History, Rainfall and Management in Fire-Maintained EcosystemsThe combined effects of repeated fires, climate, and landscape features (e.g., edges) need greater focus in fire ecology studies, which usually emphasize characteristics of the most recent fire and not fire history. Florida scrub-jays are an imperiled, territorial species that prefer medium (1.2-1.7 m) shrub heights. We measured short, medium, and tall habitat quality states annually within 10 ha grid cells that represented potential territories because frequent fires and vegetative recovery cause annual variation in habitat quality. We used multistate models and model selection to test competing hypotheses about how transition probabilities between states varied annually as functions of environmental covariates. Covariates included vegetative type, edges, precipitation, openings (gaps between shrubs), mechanical cutting, and fire characteristics. Fire characteristics not only included an annual presenceabsence of fire covariate, but also fire history covariates: time since the previous fire, the maximum fire-free interval, and the number of repeated fires. Statistical models with support included many covariates for each transition probability, often including fire history, interactions and nonlinear relationships. Tall territories resulted from 28 years of fire suppression and habitat fragmentation that reduced the spread of fires across landscapes. Despite 35 years of habitat restoration and prescribed fires, half the territories remained tall suggesting a regime shift to a less desirable habitat condition. Measuring territory quality states and environmental covariates each year combined with multistate modeling provided a useful empirical approach to quantify the effects of repeated fire in combinations with environmental variables on transition probabilities that drive management strategies and ecosystem change.
Document ID
20180000123
Acquisition Source
Kennedy Space Center
Document Type
Preprint (Draft being sent to journal)
Authors
Breininger, David R.
(Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Foster, Tammy E.
(Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Carter, Geoffrey M.
(Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Duncan, Brean W.
(Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Stolen, Eric D.
(Integrated Mission Support Services, LLC Merritt Island, FL, United States)
Lyon, James E.
(Fish and Wildlife Service Titusville, FL, United States)
Date Acquired
January 5, 2018
Publication Date
January 1, 2017
Subject Category
Life Sciences (General)
Statistics And Probability
Report/Patent Number
KSC-E-DAA-TN41508
Funding Number(s)
CONTRACT_GRANT: NNK16OB01C
Distribution Limits
Public
Copyright
Public Use Permitted.
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