Multistate modeling of habitat dynamics: factors affecting Florida scrub transition probabilities

Integrating Land Cover Modeling and Adaptive Management to Conserve Endangered Species and Reduce Catastrophic Fire Risk

“…Funding for conducting prescribed fires is often specified for fuel management and not necessarily for species habitat management; administrators from agencies often measure the performance of prescribed fire programs using the acreage burned each year, which provides little information on scrub habitat quality trajectories, because fire intensity and outcomes are heterogeneous [10]. Our studies have shown that an emphasis on fuel management will not achieve species conservation goals on many conservation lands [9,18]. Wildland fire managers and ecologists agree that prescribed fires can be beneficial, and we believe that differences in management approaches are reconcilable, but require stakeholders to acknowledge multiple values and agree: (1) on the legitimacy of objectives arising from these values; (2) on how to measure whether management is attaining those objectives; and (3) on how decisions should be made.…”

“…Although tall scrub does not ignite easily, it represents a hazard once it ignites. Because scrub regrowth is often a function of underground biomass, many ecologists have observed that tall scrub recovers much faster than scrub that has been subjected to frequent fires [9]. Fire managers usually rely on a return interval to determine when a managed area needs to burn, which differs from the typical ARM approach, which recommends using current values of time-specific state variables (e.g., habitat states from Table 1) to determine the optimal management action [18].…”

“…We describe two competing models, where the first model predicts that the two types of prescribed fires can be implemented successfully to produce different consequences (probabilistically), while the second model predicts that the consequences of these two types of prescribed fires cannot be differentiated (i.e., that it is not really possible to implement habitat fires; thus both kinds of fires produce the same system responses). In our example, we rely on estimates already made for fuel reduction fires [9,18] and estimates solicited from managers and biologists that can be updated by monitoring.…”

“…In our approach, land cover is characterized by discrete successional stages that represent habitat quality, as defined on a geographic scale (10 ha), representing average territory size and, therefore, relevant to FSJ recruitment and survival (Table 1, [8][9][10]). Table 1.…”

“…Table 1. Habitat states used to quantify landscape units as potential territories (10 ha) of Florida scrub-jays (FSJs) directly related to long-term demographic performance (yearling production rates; breeder mortality rates) and fire history successional patterns (adapted from [8][9][10]). Populations are expected to increase in landscapes dominated by source territories (positive demographic performance) or to decrease in landscapes dominated by sink territories (negative demographic performance).…”