Spatiotemporal Patterns of Mammalian Use of Everglades Tree Islands

Authors

Marcel A. BozasFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Earth Systems Science

First Advisor's Name

Michael Ross

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Hong Liu

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Jennifer Rehage

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Alessandro Catenazzi

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Craig van der Heiden

Fifth Advisor's Committee Title

Committee Member

Keywords

tree island, metacommunity, community, diversity, spatiotemporal, habitat use, Everglades, Florida, wildlife, mammal, mammalian, bear

Date of Defense

4-25-2024

Abstract

Tree islands are spatially discrete ecosystem patches of woody vegetation that developed from natural processes within a matrix of dissimilar vegetation. Tree islands ecosystems are distributed across the globe and occur in a remarkably wide range of environmental conditions, but share a common mechanism of formation and maintenance: tree islands form in stressful landscapes by colonizing microsites where environmental stress is low enough to permit survival of woody species, then positive feedbacks stimulate endogenous growth. Another common thread shared by tree islands, globally, is that most of the regional wildlife is heavily dependent on tree islands for habitat and other resources. Five years of monitoring the mammal metacommunity on tree islands in the Florida Everglades supported this concept and revealed species differentially used tree islands primarily based on hydrologic stress and functional connectivity of the landscape. Marsh amplitude, patch size, and percent area of neighboring tree island patches influenced metacommunity structure and species distributions, but these effects paled in comparison to that of local marsh water depth. Tree islands with low levels of hydrologic stress (i.e., local marsh water depth) supported diverse mammal communities and exhibited higher levels of habitat use. Mammal diversity and habitat use steadily declined as hydrologic stress increased, until the community was predominantly composed of myomorphs and black bear, as these species are particularly well-suited for occupying mesic sites and traversing deeply inundated matrices. Further investigation of black bears’ spatial and temporal use of Everglades tree islands indicated that despite bears’ ability to cope with mesic or inundated conditions, bears selected for tree islands with shallower marsh depths and cubs were especially sensitive to tree island hydroperiod. Bears also increasingly used tree islands with large patch sizes, as these sites provide more space and resources. The most important resource to bears in the Everglades appeared to be the availability of soft mast forage. Spatiotemporal variation of this resource was strongly related to bear distribution and habitat use. Temporal changes in soft mast availability were also synchronous with changes in bears’ biological seasons; thus, these effects could not be fully teased apart.

Identifier

FIDC010982

Recommended Citation

Bozas, Marcel A., "Spatiotemporal Patterns of Mammalian Use of Everglades Tree Islands" (2024). FIU Electronic Theses and Dissertations. 5185.
https://digitalcommons.fiu.edu/etd/5185