Tree Island Response to Fire and Flooding in the Short-Hydroperiod Marl Prairie Grasslands of the Florida Everglades

Within the marl prairie grasslands of the Florida Everglades, USA, the combined effects of fire and flooding usually lead to very significant changes in tree island structure and composition. Depending on fire severity and post-fire hydroperiod, these effects vary spatially and temporally throughout the landscape, creating a patchy post-fire mosaic of tree islands with different successional states. Through the use of the Normalized Difference Vegetation Index (NDVI) and three predictor variables (marsh water table elevation at the time of fire, post-fire hydroperiod, and tree island size), along with logistic regression analysis, we examined the probability of tree island burning and recovering following the Mustang Corner Fire (May to June 2008) in Everglades National Park. Our data show that hydrologic conditions during and after fire, which are under varying degrees of management control, can lead to tree island contraction or loss. More specifically, the elevation of the marsh water table at the time of the fire appears to be the most important parameter determining the severity of fire in marl prairie tree islands. Furthermore, in the post-fire recovery phase, both tree island size and hydroperiod during the first year after the fire played important roles in determining the probability of tree island recovery, contraction, or loss.

Woody Plant Invasion into the Freshwater Marl Prairie Habitat of the Cape Sable Seaside Sparrow: Final Report

In the fall of 2005, U.S. Fish and Wildlife Services (USFWS) contracted with Florida International University (FIU) to study the physical and biological drivers underlying the distribution of woody plant species in the marl prairie habitat of the Cape Sable Seaside Sparrow (CSSS). This report presents what we have learned about woody plant encroachment based on studies carried out during the period 2006-2008. The freshwater marl prairie habitat currently occupied by the Cape Sable seaside sparrow (CSSS; Ammodramus maritimus mirabilis) is a dynamic mosaic comprised of species-rich grassland communities and tree islands of various sizes, densities and compositions. Landscape heterogeneity and the scale of vegetative components across the marl prairie is primarily determined by hydrologic conditions, biological factors (e.g. dispersal and growth morphology), and disturbances such as fire. The woody component of the marl prairie landscape is subject to expansion through multiple positive feedback mechanisms, which may be initiated by recent land use change (e.g. drainage). Because sparrows are known to avoid areas where the woody component is too extensive, a better understanding of invasion dynamics is needed to ensure proper management.

[Poster] Friends of the Island

This poster presentation will exhibit the ongoing design work within two small islands adjacent to Diner Key Marina gifted by the City of Miami to the non-profit organization, Shake-A-Leg. This organization works to blur the lines between access, recreation, and skill, redefining what is possible. Abled and disabled children, adolescents, and young adults go to Shake-A-Leg to participate in a myriad of activities such as sailing, kayaking, swimming, painting, and socializing in these islands regardless of their inadequate walkways and installations. The users are people from different social statuses, physical and mental abilities. This poster will exhibit the design proposal to enhance the islands’ infrastructure to provide seamless access to all its visitors through the lush habitat in these islands. The proposed program challenges the disabilities of the person and helps them to mediate and transform them into new possibilities and abilities. The program proposes ten components which include a nature trail, restrooms, dinning center, art studio, and observation deck. The design of each space draws from the sailing boat to create solutions were the user will explore, participate and enjoy. The location encourages a feeling of challenge but at the same time it is a place for relief and freedom, allowing them to discover the diversity through experimentation and interaction with the environment. This poster presents design principles that value equal access and experience, celebrating the differences among users and the environment, blurring the lines between nature and access.