Research Interests: Management, Environmental Science, Limnology, Mangrove, Planning, and 4 moreWetland, Swamp, Marsh, and Bay
Estuarine budget studies often suffer from uncertainties of net flux estimates in view of large temporal and spatial variabilities. Optimum spatial measurement density and material flux errors for a reasonably well mixed estuary were... more
Estuarine budget studies often suffer from uncertainties of net flux estimates in view of large temporal and spatial variabilities. Optimum spatial measurement density and material flux errors for a reasonably well mixed estuary were estimated by sampling 10 stations from surface to bottom simultaneously every hour for two tidal cycles in a 320‐m‐wide cross section in North Inlet, South Carolina. Discharge and ATP and NII4+‐N fluxes were computed. The analysis method was to form a number of cases, each based on a different number and combination of stations and compare these fluxes to the ideal case using all 10 stations. A percentage error, γ, (rms derivation of a given case from the ideal case compared to the tidal prism) was <15% with only three lateral stations, each located to cover a separate bathymetric regime. In estuaries with dimensions similar to North Inlet, these results should prove useful in selecting an optimum (or minimum) number of required stations.
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Research Interests: Environmental Science, Ecology, Salinity, Wetland, Habitat, and 3 moreEstuary, Salt marsh, and Marsh
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Question: Chronic stress events are defined as disturbance events that exceed the lifespan of the dominant plant species, fluctuate in intensity and lack abruptness or physical destruction of biomass. Can the effects of chronic stress... more
Question: Chronic stress events are defined as disturbance events that exceed the lifespan of the dominant plant species, fluctuate in intensity and lack abruptness or physical destruction of biomass. Can the effects of chronic stress events be measured on vegetation communities? Did two chronic stress events, the removal of a tide gate and a four year drought, cause a temporary or permanent shift in the vegetation communities of a tidal marsh?Location: Tidal marsh in southeastern United States.Methods: Change in species composition and dominance and community change on a landscape level salinity gradient were measured between time periods ranging from four months to seven years to construct a statistical baseline reference community at freshwater, oligohaline, and mesohaline sections of a tidal marsh. Statistical shifts in the plant community were defined as changes in the plant community that fell outside of the defined baseline reference community.Results: Plant community changes...
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Ecology of tidal freshwater forested wetlands of the southeastern United States William H. Conner Thomas W. Doyle Ken W. Krauss editors. Ecology of tidal freshwater forested wetlands of the southeastern United States. Springer, New York. 2007. xiv + p. $239.00, ISBN: 978-1-4020-5094-7 (acid-free ...more
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This report synthesizes extant literature detailing the ecology of bottomland hardwood swamps in the Southeast. The geographic scope focuses the report to the hardwoods occupying the floodplains of the rivers whose drainages originate in... more
This report synthesizes extant literature detailing the ecology of bottomland hardwood swamps in the Southeast. The geographic scope focuses the report to the hardwoods occupying the floodplains of the rivers whose drainages originate in the Appalachian Mountains/Piedmont and ...
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... 1995). Foraging habitat is generally comprised of wet prairie or slough communities (Loveless 1959) with sufficient emergent vegetation to allow apple snails to surface where they are available to kites (Bennetts et al. 1994, Bennetts... more
... 1995). Foraging habitat is generally comprised of wet prairie or slough communities (Loveless 1959) with sufficient emergent vegetation to allow apple snails to surface where they are available to kites (Bennetts et al. 1994, Bennetts and Kitchens 1997a). ...
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The U. S. Fish and Wildlife Service is implementing community succession models to forecast the impacts of altered hydrological regimes on forested floodplains and coastal marshes. A pilot project on the Santee River, South Carolina has... more
The U. S. Fish and Wildlife Service is implementing community succession models to forecast the impacts of altered hydrological regimes on forested floodplains and coastal marshes. A pilot project on the Santee River, South Carolina has demonstrated the potential for a 97% loss of bottomland hardwoods in the floodplain following diversion of the river. Artificial levee construction is also an issue in the coastal marshes in the Lower Atchafalaya River Basin, Louisiana where a marsh succession model is being employed.
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Novel ecosystems arise for a variety of reasons, most notably from the introduction of nonnative species. Understanding the interactions between traditional habitats, novel habitats, and species of conservation interest is important when... more
Novel ecosystems arise for a variety of reasons, most notably from the introduction of nonnative species. Understanding the interactions between traditional habitats, novel habitats, and species of conservation interest is important when planning successful conservation strategies. In the United States, the snail kite Rostrhamus sociabilis plumbeus is a federally endangered species whose population in Florida has undergone declines within the past decade. While studying the foraging behavior of breeding snail kites on Lake Tohopekaliga (Lake Toho), we discovered the unexpected use of disturbed ephemeral wetlands adjacent to the lake. These wetlands represent a novel habitat for snail kites; they would not have been viable foraging areas prior to the introduction of the exotic island apple snail Pomacea maculata. By examining the differences between snail kite behavior in traditional and novel habitats, we were able to identify some characteristics of novel habitats that may be impor...
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Understanding the spatial scale of population structure is fundamental to long-standing tenets of population biology, landscape ecology and conservation. Nonetheless, identifying such scales has been challenging because a key factor that... more
Understanding the spatial scale of population structure is fundamental to long-standing tenets of population biology, landscape ecology and conservation. Nonetheless, identifying such scales has been challenging because a key factor that influences scaling - movement among patches or local populations - is a multicausal process with substantial phenotypic and temporal variation. We resolve this problem via a novel application of network modularity. When applied to movements, modularity provides a formal description of the functional aggregation of populations and identifies potentially critical scales for ecological and evolutionary dynamics. We first test for modularity using several different types of biologically relevant movements across the entire geographic range of an endangered bird, the snail kite (Rostrhamus sociabilis plumbeus). We then ask whether variation in movement based on (i) age, (ii) sex and (iii) time (annual, seasonal and within-season movements) influences spa...
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Understanding dispersal and habitat selection behaviours is central to many problems in ecology, evolution and conservation. One factor often hypothesized to influence habitat selection by dispersers is the natal environment experienced... more
Understanding dispersal and habitat selection behaviours is central to many problems in ecology, evolution and conservation. One factor often hypothesized to influence habitat selection by dispersers is the natal environment experienced by juveniles. Nonetheless, evidence for the effect of natal environment on dispersing, wild vertebrates remains limited. Using 18 years of nesting and mark–resight data across an entire North American geographical range of an endangered bird, the snail kite (Rostrhamus sociabilis), we tested for natal effects on breeding-site selection by dispersers and its consequences for reproductive success and population structure. Dispersing snail kites were more likely to nest in wetlands of the same habitat type (lacustrine or palustrine) as their natal wetland, independent of dispersal distance, but this preference declined with age and if individuals were born during droughts. Importantly, dispersing kites that bred in natal-like habitats had lower nest suc...
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ABSTRACT Remote sensing of wetlands has primarily focused on delineating wetlands within a non-wetland matrix. However, within-wetland changes are arguably just as important as loss of wetland area, particularly in a time of accelerated... more
ABSTRACT Remote sensing of wetlands has primarily focused on delineating wetlands within a non-wetland matrix. However, within-wetland changes are arguably just as important as loss of wetland area, particularly in a time of accelerated climate change. Remote sensing is a critical source of data for ecological models that explain and predict landscape changes, but data specifications, including spatial and temporal resolution, must be appropriate for applications. Unmanned Aircraft Systems (UASs) can be used to collect fine spatial resolution data with a temporal resolution more tailored to application need, instead of satellite orbital times or flight schedules. We used data collected from an UAS to acquire true color data within a wetland landscape and tested our ability to automatically classify plant communities from fine-resolution data. Classification accuracies were low for certain classes when nine vegetation communities were mapped, but the overall accuracy was on par with other remote sensing analyses. We demonstrate that classification data derived from UAS fine-resolution imagery is reasonably accurate and discuss the benefits and challenges of using UAS for wetland mapping.
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... Althea S. Hotaling 1, * , H. Franklin Percival 1 , Wiley M. Kitchens 1 and John W. Kasbohm 2. ... and duration of the fluctuations varying widely among species and even among populations of the same species (Getz and McGuire 2009,... more
... Althea S. Hotaling 1, * , H. Franklin Percival 1 , Wiley M. Kitchens 1 and John W. Kasbohm 2. ... and duration of the fluctuations varying widely among species and even among populations of the same species (Getz and McGuire 2009, Krebs 1996, Krebs and Myers 1974, Krebs et ...
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Deriving valid inferences about the causes and consequences of dispersal from empirical studies depends largely on our ability reliably to estimate parameters associated with dispersal. Here, we present a review of the methods available... more
Deriving valid inferences about the causes and consequences of dispersal from empirical studies depends largely on our ability reliably to estimate parameters associated with dispersal. Here, we present a review of the methods available for estimating dispersal and related parameters using marked individuals. We emphasize methods that place dispersal in a probabilistic framework. In this context, we define a dispersal event as a movement of a specified distance or from one predefined patch to another, the magnitude of the distance or the definition of a `patch? depending on the ecological or evolutionary question(s) being addressed. We have organized the chapter based on four general classes of data for animals that are captured, marked, and released alive: (1) recovery data, in which animals are recovered dead at a subsequent time, (2) recapture/resighting data, in which animals are either recaptured or resighted alive on subsequent sampling occasions, (3) known-status data, in which marked animals are reobserved alive or dead at specified times with probability 1.0, and (4) combined data, in which data are of more than one type (e.g., live recapture and ring recovery). For each data type, we discuss the data required, the estimation techniques, and the types of questions that might be addressed from studies conducted at single and multiple sites. Additional publication details Publication type Book chapter Publication Subtype Book Chapter Title Methods for estimating dispersal probabilities and related parameters using marked animals Year Published 2001 Language English Publisher Oxford University Press Publisher location Oxford Contributing office(s) Patuxent Wildlife Research Center Description 448 Larger Work Type Book Larger Work Subtype Other Government Series Larger Work Title Dispersal First page 3 Here's how you know Methods for estimating di persal probabilities and related parameters using marked animals
Research Interests: Geography and Statistics
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Research Interests: Biology, Ecology, Endangered Species, Habitat, Wildlife, and 3 moreTrapping, Salt marsh, and Camera Trap
The Arthur R. Marshall Loxahatchee National Wildlife Refuge (Loxahatchee) is a remnant of the northern Everglades wetlands. Tree islands are a prominent feature of the landscape. Despite their prominence in the landscape, few studies... more
The Arthur R. Marshall Loxahatchee National Wildlife Refuge (Loxahatchee) is a remnant of the northern Everglades wetlands. Tree islands are a prominent feature of the landscape. Despite their prominence in the landscape, few studies specifically on the ecological importance of tree islands have been conducted. This chapter reviews and summarizes what studies have been done in Loxahatchee that provide information on tree islands. The studies reviewed fall in to four basic categories: 1) Characterization and distribution, 2) Vegetation composition, 3) Tree island change and 4) Faunal use. The data on tree island origin in Loxahatchee suggest two possible routes of formation for tree islands: development from floating batteries or peat mats, or formation along the ridges in the ridge and slough landscape. Most of the tree islands in Loxahatchee are small, round or elliptical, and slightly elevated islands that may have formed via the former mechanism. Tree islands are not distributed uniformly throughout Loxahatchee, with more small islands in the north and west. Natural processes such as fire and hydrology have, and continue to play a role in tree island structure and distribution. Tree islands in areas of longer hydroperiod and deeper water depths have decreased in size, probably as a result of flooding, while tree islands in drier areas have increased in size and developed less distinctive shapes (no longer round or elliptical). There is evidence that fire occurred on islands. One study showed how fire can structure the islands by burning the vegetation along the outside and leaving the interior vegetation intact. Seventy plant species and 86 vertebrate species have been observed on or associated with tree islands. The studies reviewed in this chapter span a period of 50+ years and provide a recent historical basis for evaluating tree island change. These past studies provide us with a starting point for development and testing of hypothesis on the ecological importance of tree islands in Loxahatchee and the rest of the Everglades.
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... Zachariah C. Welch and ... 1 = East Lake Tohopekaliga 2 = West Lake Tohopekaliga 3 = Lake Kissimmee 4 = Blue Cypress Marshes 5 = Lake Okeechobee 6 = West Palm Beach Water Catchment Area 7 = ARM Loxahatchee National Wildlife Refuge 8 =... more
... Zachariah C. Welch and ... 1 = East Lake Tohopekaliga 2 = West Lake Tohopekaliga 3 = Lake Kissimmee 4 = Blue Cypress Marshes 5 = Lake Okeechobee 6 = West Palm Beach Water Catchment Area 7 = ARM Loxahatchee National Wildlife Refuge 8 = Water Conservation Area ...
Research Interests: Environmental Science, Fishery, Snail, Population Change, Swamp, and 3 moreMarsh, Breeding season, and Cypress
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Abstract. In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite... more
Abstract. In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.