Digital Commons Network^™

A Review Of Subtropical Community Resistance And Resilience To Extreme Cold Spells, Ross E. Boucek, Evelyn E. Gaiser, H. Liu, Jennifer S. Rehage

FCE LTER Journal Articles

Forecasted changes in global climate predict not only shifts in average conditions but also changes in the frequency and intensity of climate extremes. In the subtropics, the passage of extreme cold spells functions as a major structuring force for ecological communities, and can incur substantial losses to biodiversity, agriculture, and infrastructure. If these events persist in the future, it is likely that their effects on subtropical communities and ecosystems will become more pronounced, as tropical species migrate poleward. Recent extreme cold spells in subtropical China (2008) and United States (2010) occurred in ecosystems that are the subject of long-term ecological …

Towards A Cohesive, Holistic View Of Top Predation: A Definition, Synthesis And Perspective, Fabrizio Sergio, Oswald J. Schmitz, Charles J. Krebbs, Robert D. Holt, Michael R. Heithaus, Aaron J. Wirsing, William J. Ripple, Euan Ritchie, David Ainley, Daniel Oro, Yadvendradev Jhala, Fernando Hiraldo, Erkki Korpimäki

FCE LTER Journal Articles

The ongoing global loss of top predators and their recolonization of various regions are causing a rapid upsurge of studies on these species and a consequent fragmentation of this field into disconnected, specialized subcompartments: this will weaken efforts to produce synthetic generalisations of broader ecological interest. Here, we show that top predation provides regular contributions to general ecology, is well grounded in theoretical ecology and is a rapidly expanding and increasingly experimental, multidisciplinary and technological field of research. The novelty of this forum lies in providing a concise synthesis of this area of ecology, in attempting to formalise “top predation” …

Seasonal Fish Dispersal In Ephemeral Wetlands Of The Florida Everglades, Charles W. Goss, William F. Loftus, Joel C. Trexler

FCE LTER Journal Articles

We hypothesized that fishes in short-hydroperiod wetlands display pulses in activity tied to seasonal flooding and drying, with relatively low activity during intervening periods. To evaluate this hypothesis, sampling devices that funnel fish into traps (drift fences) were used to investigate fish movement across the Everglades, U.S.A. Samples were collected at six sites in the Rocky Glades, a seasonally flooded karstic habitat located on the southeastern edge of the Everglades. Four species that display distinct recovery patterns following drought in long-hydroperiod wetlands were studied: eastern mosquitofish (Gambusia holbrooki) and flagfish (Jordanella floridae) (rapid recovery); and bluefin …

A Review Of The Effects Of Altered Hydrology And Salinity On Vertebrate Fauna And Their Habitats In Northeastern Florida Bay, Jerome J. Lorenz

FCE LTER Journal Articles

Estuarine productivity is highly dependent on the freshwater sources of the estuary. In Florida Bay, Taylor Slough was historically the main source of fresh water. Beginning in about 1960, and culminating with the completion of the South Dade Conveyance System in 1984, water management practice began to change the quantity and distribution of flow from Taylor Slough into Northeastern Florida Bay. These practices altered salinity and hydrologic parameters that had measurable negative impacts on vertebrate fauna and their habitats. Here, I review those impacts from published and unpublished literature and anecdotal observations. Almost all vertebrates covered in this review have …

Multi-Tissue Stable Isotope Analysis And Acoustic Telemetry Reveal Seasonal Variability In The Trophic Interactions Of Juvenile Bull Sharks In A Coastal Estuary, Philip Matich, Michael R. Heithaus

FCE LTER Journal Articles

1. Understanding how natural and anthropogenic drivers affect extant food webs is critical to predicting the impacts of climate change and habitat alterations on ecosystem dynamics.
2. In the Florida Everglades, seasonal reductions in freshwater flow and precipitation lead to annual migrations of aquatic taxa from marsh habitats to deep-water refugia in estuaries. The timing and intensity of freshwater reductions, however, will be modified by ongoing ecosystem restoration and predicted climate change.
3. Understanding the importance of seasonally pulsed resources to predators is critical to predicting the impacts of management and climate change on their populations. As with many large predators, however, it …

Mechanisms Of Bicarbonate Use Influence The Photosynthetic Carbon Dioxide Sensitivity Of Tropical Seagrasses, Justin E. Campbell, James W. Fourqurean

FCE LTER Journal Articles

The photosynthetic bicarbonate () use properties of three widely distributed tropical seagrasses were compared using a series of laboratory experiments. Photosynthetic rates of Thalassia testudinum, Halodule wrightii, and Syringodium filiforme were monitored in an enclosed chamber while being subjected to shifts in pH and dissolved inorganic carbon. Specific mechanisms of seagrass use were compared by examining the photosynthetic effects of the carbonic anhydrase inhibitor acetazolamide (AZ). All seagrasses increased photosynthetic rates with reduced pH, suggesting a large effect of dissolved aqueous carbon dioxide (CO_2(aq)). However, there was considerable interspecific variation in pH response. T. testudinum was …

Surprises And Insights From Long-Term Aquatic Data Sets And Experiments, Walter K. Dodds, Christopher T. Robinson, E. E. Gaiser, Gretchen J.A. Hansen, Heather Powell, Joseph M. Smith, Nathaniel B. Morse, Sherri L. Johnson, Stanley V. Gregory, Tisza Bell, Timothy K. Kratz, William H. Mcdowell

FCE LTER Journal Articles

long-term research on freshwater ecosystems provides insights that can be difficult to obtain from other approaches. Widespread monitoring of ecologically relevant water-quality parameters spanning decades can facilitate important tests of ecological principles. Unique long-term data sets and analytical tools are increasingly available, allowing for powerful and synthetic analyses across sites. long-term measurements or experiments in aquatic systems can catch rare events, changes in highly variable systems, time-lagged responses, cumulative effects of stressors, and biotic responses that encompass multiple generations. Data are available from formal networks, local to international agencies, private organizations, various institutions, and paleontological and historic records; brief literature …

Heterogeneity In Residential Yard Care: Evidence From Boston, Miami, And Phoenix, Edmund M. Harris, Colin Polsky, Kelli L. Larson, Rebecca Garvoille, Jaleila Brumand, Laura Ogden

FCE LTER Journal Articles

The management of residential landscapes occurs within a complex socio-ecological system linking household decision-making with ecological properties, multi-scalar human drivers, and the legacy effects of past management. Conventional wisdom suggests that resource-intensive turf grass yards are the most common landscaping outcome, resulting in a presumed homogeneous set of residential landscaping practices throughout North America. We examine this homogenization thesis through an interview-based, cross-site study of residential landscape management in Boston, Phoenix, and Miami. Counter to the homogeneity thesis, we find that yard management practices often exhibit heterogeneity, for example, in groundcover choice or use of chemical inputs. The degree of …

Slow Isotope Turnover Rates And Low Discrimination Values In The American Alligator: Implications For Interpretation Of Ectotherm Stable Isotope Data, Adam E. Rosenblatt, Michael R. Heithaus

FCE LTER Journal Articles

Stable isotope analysis has become a standard ecological tool for elucidating feeding relationships of organisms and determining food web structure and connectivity. There remain important questions concerning rates at which stable isotope values are incorporated into tissues (turnover rates) and the change in isotope value between a tissue and a food source (discrimination values). These gaps in our understanding necessitate experimental studies to adequately interpret field data. Tissue turnover rates and discrimination values vary among species and have been investigated in a broad array of taxa. However, little attention has been paid to ectothermic top predators in this regard. We …

Interspecific Variation In The Elemental And Stable Isotope Content Of Seagrasses In South Florida, Justin E. Campbell, James W. Fourqurean

FCE LTER Journal Articles

The elemental (C, N, and P) and isotope (δ13C, δ15N) content of leaves of the seagrasses Thalassia testudinum, Halodule wrightii, and Syringodium filiforme were measured across a 10 000 km2 survey of the seagrass communities of South Florida, USA, in 1999 and 2000. Trends at local and broad spatial scales were compared to examine interspecific variation in the seagrass characteristics often used as ecological indicators. The elemental and stable isotope contents of all species were variable and demonstrated marked interspecific variation. At broad spatial scales, mean N:P ratios were lowest for T. testudinum (36.5 ± 1.1) and S. filiforme (38.9 …

Hydrologic Measurements And Implications For Tree Island Formation Within Everglades National Park, Jose Bazante, Gary Jacobi, Helena M. Solo-Gabriele, David Reed, Sherry Mitchell-Bruker, Daniel L. Childers, Lynn Leonard, Michael Ross

FCE LTER Journal Articles

Tree islands in the Shark River Slough of the Everglades National Park (ENP), in the southern state of Florida in the United States, are part of a wetland system of densely vegetated ridges interspersed within relatively open sloughs. Human alteration of this system has had dramatic negative effects on the landscape of the region and restoration efforts will require adjusting the hydrology of the region to assure the preservation of these important ecologic features. The primary objectives of this study were to document the hydrology in the vicinity of tree islands in ENP by measuring velocities in time and space …