Marl Prairie Projects
2002-Present — Effect of Hydrologic Restoration on the Habitat of the Cape Sable Seaside Sparrow:
Protecting the breeding habitats of endangered birds is essential for species recovery. The Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis; CSSS) is currently listed under the Endangered Species Act. This bird nests within the seasonally flooded short hydroperiod marshes of the interior portions of the Everglades. At present, it is estimated that 2000 pairs of CSSS remain in six populations. Existing research indicates that CSSS populations fluctuate widely in response to hydrologic conditions, but the relationships are not adequately known nor the mechanisms well understood. Current thinking is that the linkage is at least in part the result of hydrologically driven changes in vegetation. Our portion of the study was designed to assess vegetation dynamics as they relate to hydrologic conditions within the six sparrow populations. The broad study design was intended to tie our work together with several other research and monitoring efforts in the broad landscape occupied by the Cape Sable seaside sparrow.
2004-Present — Woody plant invasion in marl prairie habitat of the Cape Sable seaside sparrow:
In addition to species-rich grassland communities, the fresh water marl prairie habitat currently occupied by the Cape Sable seaside sparrow includes tree islands, tree patches, and individual trees. It is known that sparrows avoid areas where the woody plant component is too extensive, possibly in response to increased predator activity (Jenkins et al. 2003). Jenkins and co-authors summarized the influence of woody plants in the landscape on the basis of coarse scale (pixel size = 30 x 30 m) satellite imagery, but the structure of these woody plant populations was not examined in detail. In order to develop a better understanding of invasion dynamics, and ultimately its effects on sparrow populations, it is important to supplement remote sensing efforts with field investigations of woody plant population processes. We are currently working to develop statistical models that predict marsh invasion by important woody species from seed sources in existing hammocks and groups of trees, and design a landscape index that can be applied on the basis of emerging remote sensing technologies.
2002-2003 — Vegetation Dynamics in ENP marshes, with emphasis on Taylor Slough:
The marsh communities on Department of Interior lands in Everglades National Park (ENP) and Big Cypress National Preserve are critical components in the biodiversity of the Everglades, both for the structure they provide in support of other biotic elements, and for the intrinsic values of their constituent plant species assemblages. Maintaining or returning these marshes to good condition is a fundamental goal of the federal/state restoration partnership. Furthermore, the restoration plans carry an implicit assumption that providing the “right” hydrology will translate directly and rapidly into the desired marsh community. However, while no one questions that the ecology of these marshes is inextricably bound to their hydrology, they remain complex ecosystems driven by multiple variables, both physical and biological, that could delay or modify the trajectories intended by hydrologic restoration. One avenue of assessing the likelihood of success for hydrologic restoration is by examining the responses of vegetation to hydrology as they have unfolded in the past. In this project, we examined the temporal and spatial co-variation of vegetation and hydrology in seasonally flooded marshes, focusing specifically on the upper reaches of Taylor Slough during the period 1979-2003.