Restoration ecology

Sponges (phylum Porifera) are ancient animals that provide numerous ecosystem functions (e.g., water filtration, habitat, food source) and commercial applications (e.g., bath sponges and pharmaceuticals). However, mass mortality events in Florida Bay have drastically impacted sponge communities and the ecosystem services they provide. To restore habitats, sponge restoration initiatives are ongoing in Florida. The aim of this thesis was to determine survival and growth of sponges in a land-based nursery. Larvae from four species were collected from the Indian River Lagoon and the Florida Keys from July to September 2021. Larval settlement and metamorphosis, survival of recruits, morphological development and growth were observed, quantified, and compared to other species. Larvae settlement success was highest in our Heteroscleromorpha species Tedania ignis, Haliclona caerulea and Niphates erecta, but not the Keratosa species Spongia sp. However, the highest recruit survival was the Spongia sp. Early developmental characteristics were significantly different among species and over observation periods, with most developmental characteristics occurring during the first 14 days post-settlement. H. caerulea and Spongia sp. developed faster than other species. Spongia sp. recruit growth was higher when kept in artificial seawater with no food supplement. These results provide further insight toward optimizing the FAUHBOI sponge nursery protocols to supplement current restoration efforts and increase the abundance of sponge populations and community diversity.

One of the largest restoration programs in the world, the Comprehensive Everglades Restoration Plan (CERP) aims to restore freshwater flows to the Everglades and Florida Bay estuary. Coupled with climate change, future changes from restoration highlight the need to implement an ecosystem-based fisheries management (EBFM) approach in Florida Bay. The Ecopath framework was used to develop and apply a mass-balanced food web model to the spatiotemporal dynamics of hydrological restoration and climate change through time. Results suggest Florida Bay is stabilized through large detrital energy pathways and low nutrient inputs, but subject to species distribution shifts due primarily to sea-level rise and salinity variation. A suite of winners and losers predicted provide an opportunity to ensure management strategies are designed appropriately to best achieve desired results for the future of the Florida Bay ecosystem.

Seagrasses are important foundation species in coastal ecosystems. Genetic
diversity of seagrasses can influence a number of ecological factors including, but not
limited to, disturbance resistance and resilience. Seagrasses in the Indian River Lagoon
(IRL), Florida are considered to be highly disturbed due to frequent events, like algal
blooms, that impair water quality, reducing available light for seagrass growth. Halodule
wrightii is a dominant seagrass throughout the IRL, but its genetic diversity has only been
quantified in a few Gulf of Mexico and Florida Bay populations and little is known about
its potential ecological consequences. I quantified the genetic variation of H. wrightii
using microsatellite markers in the southern IRL to determine: (i) how disturbance history
influenced genetic diversity, (ii) if morphology of clones was, in part, genetically
controlled and related to disturbance history, and (iii) if genotypes showed phenotypic
plasticity in response to disturbances. In the IRL, H. wrightii populations exhibited moderate genetic diversity that varied with disturbance history. The disturbance history
of a population was classified by the variance in the percent occurrence of H. wrightii
over a 16-year period. Genotypic richness and clonal diversity of H. wrightii increased
with increasing disturbance histories. Other genetic diversity measures (e.g., allelic
richness, observed heterozygosity) did not change with disturbance history. These
findings suggest that impacts to seagrass coverage over time can change the genotypic
composition of populations. When different genotypes of H. wrightii were grown in a
common garden, differences in leaf characteristics among genotypes provided evidence
that morphological trait variation is, in part, explained by genetic variance. The
disturbance history of genotypes did not directly affect morphological traits. However,
significant genotype x site (within disturbance history) interactions found greater
variation in shoot density and below ground traits of H. wrightii genotypes from sites of
intermediate disturbance history. Traits of H. wrightii were shown to be phenotypically
plastic. Significant genotype x environment interactions for shoot density and height
demonstrated that genotypes responded differently by increasing, decreasing, and not
changing sizes in response to light reduction. Genetic diversity of H. wrightii has strong
implications for ecological function in coastal communities.

This study created an ecological spatial model, using a geographic information system, to visualize the influence of hydrochory on restoration of the three dominant wetland communities of broadleaf marsh, wetland shrub, and wet prairie across the floodplain of the Kissimmee River. Primary parameters incorporated into the model included floodplain hydrology, seed characteristics of buoyancy and dispersal rates, and species flood tolerance. S²rensen's similarity index, comparing spatial agreement among model output and observed community data, resulted in values of BLM-BB = 0.10, BLM = 0.07, WS = 0.21, and WP = 0.36. The significant discrepancies between modeled and observed community spatial coverage indicated a need for incorporation of more stochastic variables of climatic disturbances, nutrient availability, and soil characteristics. More research on species flood tolerance across smaller spatial scales is also needed, and base data incorporated into the model should also be reliable and consistent if accuracy is to be achieved.

Variation in the seasonal water level fluctuations of tropical and subtropical wetlands controls the production and concentration of aquatic fauna that support breeding wading birds. However, little is known about how particular components of the annual hydrologic cycle affect processes that control food availability and reproduction. This thesis identifies specific mechanisms responsible for transforming wet season prey standing stock into dry season prey concentrations, links landscape hydrological patterns to wading bird nesting, and presents a predictive model of Wood Stork nesting. I examined the supoort for several a priori hypotheses of factors affecting wading bird prey concentrations and wading bird nest effort. Factors affecting the concentration and vulnerability of prey were important for transferring secondary production to higher trophic levels. Receding water levels, microtopographic variation, and high standing stocks of prey were critical for generating pulses of food availabiltiy to meet the high energy requirements of breeding predatory birds.

Oyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and restored oyster reefs, with special attention on snapping shrimp (Alpheus spp.) snap sounds, in the St. Lucie Estuary, Florida over a one year period. Season, estuary region, habitat and day period had an effect on sound production. Passive acoustic monitoring of snapping shrimp sound production may be a useful non-destructive technique for monitoring the progress of oyster reef restoration projects once further correlations are established between environmental effects and sound production.

The construction of Abacoa included an attempt to conserve the wildlife in a Greenway, a set of habitats separated from the residential and commercial areas. All of the wetlandswith in Abacoa represent artificially constructed ponds, canals, and streams first created from 1998-2004. The present study focuses on the anuran (i.e., frog and toad) populations and looks at the number of different species that have naturally colonized six differnet sites around Abacoa. Each of these sites varies in qualities that may affect the probability of breeding in that section. The quality of water is known to be less ideal as the water flows away from the headwaters and mixes with water from other sources. This study aims to determine which anuran species are found at each of these sites after nearly a decade of colonization, and how both anuran diversity and abundance correlates with water and habitat quality.

Extensive blooms of the marine cyanobacterium Lyngbya majuscula occurred during 2006 in Halodule wrightii seagrass beds. We examined the effects of L. majuscula blooms on seagrass by removal treatments and assessed if this was primarily an effect of shading by conducting artificial shade treatments. We tested the effects of L. majuscula removal and artificial shading on fifty individual 0.25 m2 experimental seagrass plots infested with L. majuscula in a fully crossed, two-way experiment. Measurements included blade elongation, biomass, and stem density. Blade lengths of H. wrightii were significantly increased by the presence of artificial shading and L. majuscula. L. majuscula removal resulted in increased below ground biomass in shaded plots, suggesting an increase in stores, when possible, for accelerated recovery following a shading event. Adverse L. majuscula effects occurred after declines in bloom biomass indicating that L. majuscula can have a prolonged negative effect on H. wrightii production.