Life Sciences Commons^™

Incorporating Early Life History And Recruitment In Analysis Of Population Dynamics Of Wetland Fishes, John Vincent Gatto

FIU Electronic Theses and Dissertations

Hydrological variation is believed to be the major abiotic factor influencing fish recruitment in floodplain ecosystems. However, past studies fail to address the impact of hydrology on the three major drivers of recruitment: age-specific growth and mortality, and dispersal. I examined long-term recruitment dynamics for six fish species inhabiting the Everglades by addressing the impact of hydrology on these important characteristics. I then linked these changes to annual fluctuations in population size.

Before interpreting time-series data on recruitment, I evaluated the impact of size-selective bias from sampling gear on our interpretation of hydrological drivers of recruitment. Analyses revealed that individuals …

Effects Of Catastrophic Seagrass Loss And Predation Risk On The Ecological Structure And Resilience Of A Model Seagrass Ecosystem, Robert J. Nowicki

FIU Electronic Theses and Dissertations

As climate change continues, climactic extremes are predicted to become more frequent and intense, in some cases resulting in dramatic changes to ecosystems. The effects of climate change on ecosystems will be mediated, in part, by biotic interactions in those ecosystems. However, there is still considerable uncertainty about where and how such biotic interactions will be important in the context of ecosystem disturbance and climactic extremes.

Here, I review the role of consumers in seagrass ecosystems and investigate the ecological impacts of an extreme climactic event (marine heat wave) and subsequent widespread seagrass die-off in Shark Bay, Western Australia. Specifically, …

Gammaridean Amphipods As Bioindicators In Subtropical Seagrass Ecosystems, Jennifer L. Sweatman

FIU Electronic Theses and Dissertations

Anthropogenic disturbances are ubiquitous in coastal marine ecosystems. As such, more intensive monitoring efforts are necessary to conserve these valuable habitats. Bioindicators, organisms that predictably respond to changes in environmental variables, may be utilized in monitoring efforts to assess ecosystem functioning. To incorporate organisms into monitoring programs as bioindicators managers need to first understand the difference between the natural phenology of the focal organisms and their responses to different forms of anthropogenic disturbance.

To determine if gammaridean amphipods could be used as indicators of changes in environmental quality in sub-tropical seagrass ecosystems, I conducted spatial and temporal surveys of amphipod …

Responses Of Four Non-Tidal Forest Communities Of The Florida Everglades To Hurricane Impact Over 21 Years, Jeremy L. May

FIU Electronic Theses and Dissertations

The regular occurrence of hurricane-associated winds has been an important factor in shaping the structure and composition of the forest ecosystems of the Florida Everglades. Forest communities in the Everglades are adapted to hurricane disturbances, but increased frequency and/or intensity of hurricanes may lead to decline or even collapse of these communities. The overall objective of this project is to understand the patterns, pace, and mechanisms of the recovery process to Hurricane Andrew damage in four Everglade forest communities: pinelands, hardwood hammocks, bayhead tree islands, and cypress domes. This study combines long- and short-term field measurements and experimental garden studies …

The Effect Of Disturbance And Freshwater Availability On Lower Florida Keys’ Coastal Forest Dynamics, Danielle E. Ogurcak

FIU Electronic Theses and Dissertations

Coastal forest retreat in the Florida Keys during the 20^th century has been attributed to a combination of sea level rise and hurricane storm surge impacts, but the interactions between these two disturbances leading to forest decline are not well understood. The goal of my research was to assess their effects over a period spanning more than two decades, and to examine the relationships between these press and pulse disturbances and freshwater availability in pine rockland, hardwood hammock, and supratidal scrub communities. Impacts and recovery from two storm surges, Hurricanes Georges (1998) and Wilma (2005), were assessed with satellite-derived …

Spatio-Temporal Analysis Of Chilling Events In Mangrove Forests Of South Florida, Bina Thapa

FIU Electronic Theses and Dissertations

Chilling events are infrequent but important disturbances in subtropical Florida. When temperatures drop to near freezing, significant mortality often accrues in mangrove forests. Chilling events play a role in maintaining structural diversity in mangrove forests, and in limiting mangrove poleward distribution. I examined the spatio-temporal distribution of chilling events in mangrove forests of southern Biscayne Bay by using Landsat TM5 images since 1989. Damage was usually confined to dwarf mangrove forest, especially when chilling temperatures were moderate and short in duration. However, damage from extended and severe freezes such as in January 2010 impacted larger trees as well. Recovery is …

Anthropogenic Disturbances In Estuarine Ecosystems: The Effects Of Altered Freshwater Inflow, Introduction Of Invasive Species, And Habitat Alteration In The Loxahatchee River, Fl, Zachary R. Jud

FIU Electronic Theses and Dissertations

With the majority of Earth’s population living in coastal areas, estuarine ecosystems have been particularly affected by anthropogenic disturbances. My dissertation research focused on three interrelated types of human disturbance that affect estuaries: Anthropogenic alteration of freshwater inflow, the introduction of invasive species, and habitat alteration. Using the LoxahatcheeRiver(Jupiter, FL) as a model system, my goal was to understand how these disturbances affect estuarine organisms, particularly fishes. One of the most ecologically harmful disturbances affecting estuaries is anthropogenic alteration of freshwater inflow (and resulting changes in salinity patterns). To identify effects of freshwater inflow on the behavior of an ecologically …