Leonard Pearlstine

An Assessment of Small Unmanned Aerial Vehicles for Wildlife Research

Abstract Aerial surveys are valuable tools for wildlife research and management. However, problems with safety, cost, statistical integrity, and logistics continue to impede aerial surveys from manned aircraft. The use of small, unmanned aerial vehicles (UAVs) may offer promise for addressing these problems and become a useful tool for many wildlife applications, such as for collecting low-altitude aerial imagery. During 2002 and 2003, we used a 1.5-m wingspan UAV equipped with autonomous control and sophisticated video equipment to test the potential usefulness of such an aircraft for wildlife research applications in Florida, USA. The UAV we used completed >30 missions (missions averaging 13 km linear distance covered) over 2 years before finally crashing due to engine failure. The UAV captured high-quality, progressive-scan video of a number of landscapes and wildlife species (white ibis [Eudocimus albus], other white wading birds, American alligator [Alligator mississippiensis], and Florida manatee [Trichechus manatus]). The UAV system was unable to collect georeferenced imagery and was difficult to deploy in unimproved areas. The performance of the autonomous control system and the quality of the progressive-scan imagery indicated strong promise for future UAVs as useful field tools. For small UAVs to be useful as management or research tools, they should be durable, modular, electric powered, launchable and recoverable in rugged terrain, autonomously controllable, operable with minimal training, and collect georeferenced imagery.

MODELLING THE IMPACTS OF A RIVER DIVERSION ON BOTTOMLAND FOREST COMMUNITIES IN THE SANTEE RIVER FLOODPLAIN, SOUTH CAROLINA

Abstract To study the impact of an altered hydrologic regime on the growth and succession of a coastal forested floodplain in South Carolina, a bottomland hardwood succession model (FORFLO) was developed. Hydrologic parameters were used as major controls for seed germination, tree growth, and tree mortality. Individual species responses to these parameters were used to predict succession (species composition) on the simulated sites. Coupling the simulation model with a geographical information mapping system permitted rapid visual inspection of predicted bottomland community changes in the Santee River floodplain. The model predicted a loss of up to 97% of the existing bottomland forest. An alternative water release schedule may retain much of this area as cypress-tupelo forest.

Modeling viable mammal populations in gap analyses

Gap analysis is an approach to conserving biological diversity that maps species richness and identifies sites that ought to be protected but are not in conservation networks. Gap analyses based on species richness may have high error rates when species models are based solely on species-habitat associations, because patches too small to support populations are still considered to be potential habitat. We incorporated information on the home range and dispersal distances of the mammals of Florida to estimate minimum critical areas (MCA) to support minimum viable populations for each mammal species. Incorporating MCA decreases the area occupied by the highest levels of species richness, and alters the mapped spatial distribution of potential species richness. For example, in St. Lucie and Okeechobee counties, Florida, the total area occupied by 15 or more species was 30,448 ha under simple mammal-habitat association models, but only 7820 ha under model conditions incorporating MCA. This reflects the fragmented condition of many landscapes, where most patches are too small to support viable populations of larger species. Incorporating minimum area requirements into maps of potential species richness produces more conservative and defensible maps.

A HABITAT SUITABILITY INDEX MODEL FOR THE EASTERN OYSTER (CRASSOSTREA VIRGINICA), A TOOL FOR RESTORATION OF THE CALOOSAHATCHEE ESTUARY, FLORIDA

Abstract A tool in the form of a habitat suitability index model (HSI) for the eastern oyster, Crassostrea virginica, was adapted to evaluate and compare the effects of alternative restoration plans in southwest Florida. A component of a large forecasting model, this tool simulates system response by examining the impact of freshwater inputs into the system. The eastern oyster is a good indicator species for modeling because of its sedentary nature and its susceptibility to natural and artificial changes. In addition, oysters form a complex three-dimensional reef structure, which provides habitat and food for numerous species of fish and invertebrates. The model focuses on salinity, temperature, depth, substrate, and high flow frequency as the particular requirements to determine habitat suitability for the eastern oyster. A geographic information system (GIS) incorporates the oyster HSI model, which includes larval and adult components, to determine responses spatially and temporally to facilitate the decision making process. This paper evaluates four hydrologic and land use scenarios for the C-43 West Basin Reservoir Project. Model results indicate that the Preferred Flow scenario and the future conditions with the Comprehensive Everglades Restoration Plan have higher HSI values then either the existing conditions or the future without the Comprehensive Everglades Plan.

SPECIES ASSOCIATION CHANGES ACROSS A GRADIENT OF FRESHWATER, OLIGOHALINE, AND MESOHALINE TIDAL MARSHES ALONG THE LOWER SAVANNAH RIVER

In the present study, plant species patterns and associated environmental factors of freshwater, oligohaline, and meschaline marshes of the Savannah National Wildlife Refuge were compared. DECORANA, an ordination method, was used to group vegetation classes. Discriminant function analysis was applied to resulting classes to quantify differences in salinity, elevation, and distance from tidal channels among classes. Nine vegetation classes across freshwater and brackish marshes corresponded significantly to salinity differences between sites. Combinations of elevation and distance from tidal channel were significant in separating vegetation classes within sites.Scirpus validus (Vahl) was the only species to occur over the entire range of measured physical parameters and accounted for much of the overlap between vegetation classes. The proportion of correctly classified vegetation classes between sites was 70%. Within each site, the proportion of correct classification was lower in the freshwater marsh (77% correct classifications) when compared with the oligohaline (82%), strongly oligohaline (83%), and mesohaline (85%) sites. Although overlap among classes was greater in the more diverse freshwater marsh, our results may reflect differences in the steepness of environmental gradients between sites and the scale at which physical parameters were measured rather than actual plant distribution overlap. Results suggest that resources are more finely divided among species in the freshwater marsh, resulting in a less distinct dominance hierarchy when compared with the mesohaline marsh.

An integrated multi-criteria scenario evaluation web tool for participatory land-use planning in urbanized areas: The Ecosystem Portfolio Model

Land-use land-cover change is one of the most important and direct drivers of changes in ecosystem functions and services. Given the complexity of the decision-making, there is a need for Internet-based decision support systems with scenario evaluation capabilities to help planners, resource managers and communities visualize, compare and consider trade-offs among the many values at stake in land use planning. This article presents details on an Ecosystem Portfolio Model (EPM) prototype that integrates ecological, socio-economic information and associated values of relevance to decision-makers and stakeholders. The EPM uses a multi-criteria scenario evaluation framework, Geographic Information Systems (GIS) analysis and spatially-explicit land-use/land-cover change-sensitive models to characterize changes in important land-cover related ecosystem values related to ecosystem services and functions, land parcel prices, and community quality-of-life (QoL) metrics. Parameters in the underlying models can be modified through the interface, allowing users in a facilitated group setting to explore simultaneously issues of scientific uncertainty and divergence in the preferences of stakeholders. One application of the South Florida EPM prototype reported in this article shows the modeled changes (which are significant) in aggregate ecological value, landscape patterns and fragmentation, biodiversity potential and ecological restoration potential for current land uses compared to the 2050 land-use scenario. Ongoing refinements to EPM, and future work especially in regard to modifiable sea level rise scenarios are also discussed.

A review of the ecological consequences and management implications of climate change for the Everglades

Abstract Southern Floridas Everglades are at the front line of potential negative effects on aquatic ecosystems from climate change and associated sea-level rise. A diversity of aquatic habitats supports a rich assemblage of aquatic and terrestrial wildlife, including 36 vertebrates and 26 plant species federally listed as endangered, threatened, or candidate species. Anticipated climate-change trends for southern Florida include increased weather uncertainty with more droughts, higher temperatures, and an increased number of more intense storms. Hydrologic regimes, temperature, and CO2 have been strongly correlated with plant community structure, coral and fish abundance and diversity, and higher trophic-level responses. Higher levels of variability in extreme climatic events, such as droughts, have the potential to destabilize aquatic communities. Sea-level rise is expected to be 0.8 to 2 m over the next century, a serious problem in a landscape that rises only 5 cm/km from Florida Bay inland. Wading birds and other wildlife species dependent on fresh water are likely to decline because of salt-water overwash and inundation. In addition to causing habitat loss, saltwater inundation of the peat substrate of Everglades freshwater wetlands may increase C emissions from sequestered C released as peat is destroyed and freshwater plant communities die. Identification of those species and habitats most at risk and ways to increase habitat and landscape resilience to large-scale environmental change will be critical for maintaining a diverse and productive Everglades.

Estimation of water surface elevations for the Everglades, Florida

The Everglades Depth Estimation Network (EDEN) is an integrated network of real-time water-level monitoring gages and modeling methods that provides scientists and managers with current (2000-present) online water surface and water depth information for the freshwater domain of the Greater Everglades. This integrated system presents data on a 400-m square grid to assist in (1) large-scale field operations; (2) integration of hydrologic and ecologic responses; (3) supporting biological and ecological assessment of the implementation of the Comprehensive Everglades Restoration Plan (CERP); and (4) assessing trophic-level responses to hydrodynamic changes in the Everglades. This paper investigates the radial basis function multiquadric method of interpolation to obtain a continuous freshwater surface across the entire Everglades using radio-transmitted data from a network of water-level gages managed by the US Geological Survey (USGS), the South Florida Water Management District (SFWMD), and the Everglades National Park (ENP). Since the hydrological connection is interrupted by canals and levees across the study area, boundary conditions were simulated by linearly interpolating along those features and integrating the results together with the data from marsh stations to obtain a continuous water surface through multiquadric interpolation. The absolute cross-validation errors greater than 5cm correlate well with the local outliers and the minimum distance between the closest stations within 2000-m radius, but seem to be independent of vegetation or season.

Textural Discrimination of an Invasive Plant, Schinus terebinthifolius, from Low Altitude Aerial Digital Imagery

Schinus terebinthifolius, known as Brazilian pepper, is an exotic, invasive plant species in Florida that displaces native plant species and disrupts wildlife habitat. Aerial surveys typically used to monitor ecosystem change may be augmented with texture analyses to improve the speed and consistency with which S. terebinthifolius is detected in the images. Image processing using high-resolution imagery can take advantage of high spectral variability in adjacent pixels of the same cover type by measuring spatial patterns of texture in neighborhoods of pixels. Texture features derived from first and second-order statistics and edge components in high-resolution digital color infrared images were tested for their ability to discriminate S. terebinthifolius. Multiple linear logistic regressions found a best subset combination of texture features that consistently identified core areas of S. terebinthifolius. Misclassification of other cover types as S. terebinthifolius was low except where Sabal palmetto was present in the images.

Using Scenario Planning to Evaluate the Impacts of Climate Change on Wildlife Populations and Communities in the Florida Everglades

It is uncertain how climate change will impact hydrologic drivers of wildlife population dynamics in freshwater wetlands of the Florida Everglades, or how to accommodate this uncertainty in restoration decisions. Using projections of climate scenarios for the year 2060, we evaluated how several possible futures could affect wildlife populations (wading birds, fish, alligators, native apple snails, amphibians, threatened and invasive species) across the Everglades landscape and inform planning already underway. We used data collected from prior research and monitoring to parameterize our wildlife population models. Hydrologic data were simulated using a spatially explicit, regional-scale model. Our scenario evaluations show that expected changes in temperature, precipitation, and sea level could significantly alter important ecological functions. All of our wildlife indicators were negatively affected by scenarios with less rainfall and more evapotranspiration. Under such scenarios, habitat suitability was substantially reduced for iconic animals such as wading birds and alligators. Conversely, the increased rainfall scenario benefited aquatic prey productivity and apex predators. Cascading impacts on non-native species is speculative, but increasing temperatures could increase the time between cold events that currently limit expansion and abundance of non-native fishes, amphibians, and reptiles with natural ranges in the tropics. This scenario planning framework underscored the benefits of proceeding with Everglades restoration plans that capture and clean more freshwater with the potential to mitigate rainfall loss and postpone impacts of sea level rise.