Kitchens, W. M. DeAngelis, D. L., Unknown, Estimation of Critical Parameters in Conjunction with Monitoring the Florida Snail Kite Population.Online Links:
U.S. Department of Agriculture - Natural Resources Conservation Service (NRCS) Department of the Interior - U.S. Geological Survey Department of Commerce - National Oceanic and Atmospheric Administration (NOAA) Environmental Protection Agency (EPA) Smithsonian Institution - National Museum of Natural History (NMNH)
Other project personnel include Julien Martin. Dr. Wolf Mooij of the Nederlands Institute of Ecology is collaborating in the development of an individual-based model on snail kites in Florida.
352 392-1861 (voice)
352 846-0841 (FAX)
kitchensw@wec.ufl.edu
The snail kite (Rostrhamus sociabilis) is an endangered species that resides in the highly fluctuating ecosystem in the central and southern Florida wetlands. Many demographic traits, such as stage-dependent survival, reproduction, and movement of the snail kite vary both temporally and spatially. How these demographic parameters vary as a function of environmental conditions, hydrology in particular, is crucial for understanding how the snail kite will respond to proposed changes in water regulation in South and Central Florida. In particular, these data are needed for testing and improving the existing spatially-explicit, individual-based ATLSS snail kite model, developed by Mooij and Bennetts, which has recently been delivered to Department of Interior and other agencies (Mooij et al. 2002). From these data and the model, projections can be made on snail kite response to any hydrologic scenario. Also, continued estimates will be made of the rate of population growth. Assessing the demographic parameters is critical for identifying and evaluating the effectiveness of management actions and conservation strategies. In addition, new modeling techniques, such as structural modeling are being explored to better understand the effects of hydrology on the snail kite.The objectives of this project are the following:
1. To monitor the status of the snail kite population trends in central and southern Florida.
2. To provide estimates of demographic parameters for the spatially explicit individual-based model in ATLSS.
3. To collaborate with Dr. Wolf Mooij of the Netherlands Institute of Ecology to use snail kite data to validate the snail kite model, EVERKITE
Mark resighting methods have a long and solid statistical foundation for estimating survival and population size. And more recently, mark-resighting methods have been developed to estimate recruitment and the rate of population change. In 1992, a mark-resighting program was initiated to estimate survival of snail kite. More recently, this approach has been used to estimate the population size and rate of population change in snail kites. Our study design continues the use of mark-resighting techniques to monitor the snail kite population. Our approach also attempted to incorporate spatial and temporal components of environmental variation (i.e., habitat conditions in wetland units, hydrological dynamics, apple snail densities) to assess how these factors influence the demographic parameters (i.e., survival and reproduction). The most efficacious approach, manipulative experiments are impractical for threatened and endangered species. We believe that the proposed approach employing observational studies that concentrate on valid parameter estimation, model selection, exploration of process variation (i.e., understanding the components of variance estimates), and examination of different factors under varying environmental conditions is the only feasible alternative.
During the sampling period, the entire study area was surveyed on 6 separate 2 to 3-week sampling occasions. Except for the repetitive sources, the format of the surveys was similar to the quasi-systematic transects conducted by airboat for the annual surveys. However, specific survey methodology depended on size, water levels, and vegetation structure in the individual wetland units. During each 2 to 3-week sampling occasion, we categorized and recorded an individual as 1) 'marked' if the bird had a colored leg band with a distinct letter/number combination so that individuals could be identified, 2) 'unmarked' if no leg bands were present or if birds were banded with only a USFWS band or color band without a letter/number combination, or 3) 'unknown' if the banding status was not determined.
Initially, it was hoped that resighting data could be used with capture-recapture models for closed populations because of the ability to model sources of variation in capture probability with these models. Thus, the first step in the analyses was testing for demographic closure. The closure test implemented in program CAPTURE and program CLOSTEST were used to test the assumption of demographic closure of the sampled population. The closure test in CAPTURE is unaffected by heterogeneity in resighting probabilities; however, it is insensitive to temporary violation of closure occurring during the middle of the sampling period. While program CLOSTEST is more robust to time-specific variation in resighting probabilities in the absence of behavioral or individual heterogeneity, its use is recommended in conjunction with the closure test in program CAPTURE in order to better detect closure violations in resighting data sets.
1. Monitoring the status of the snail kite populaiton trends in central and southern Florida 2. Providing estimates of demographic parameteres for the spatially explicit individual-based model in ATLSS 3. Continued collaboration with W. Mooij of the Netherlands Institute of Ecology to use snail kite data to validate the snail kite model EVERKITE
Person who carried out this activity:
352 392-1861 (voice)
352 846-0841 (FAX)
kitchensw@wec.ufl.edu
Kitchens, W. M. Bennetts, R. E., DeAngelis,, 2001, Linkages between the snail kite population and wetland dynamics in a highly fragmented South Florida landscape: CRC Press, Boca Raton, FL.
J. W. Porter and K. G. Porter, eds.
R., Beissinger S. , 1995, Modeling extinction in periodic environments: Everglades water levels and the Snail Kite population variability: Ecological Applications Vol. 5, no. 3, Ecological Society of America, Washington, DC.Online Links:
Pradel, R., 1996, Utilization of capture-mark-recapture for the study of recruitment and poplation growth: Biometrics Vol. 52, no.2, International Biometric Society, Washington, DC.
Lebreton, J. D. Burnham, K. P., Clobert, J., 1994, Modeling survival and testing biological hypotheses using marked animals: a unified approach with case studies: Ecological Monograph Vol. 62, Ecological Society of America, Washington, DC.
Nichols, J. D. Hines, J. E., Lebreton, J. , 2000, Estimation of contributions to population growth: a reverse-time capture-recapture approach: Ecology Vol. 81, no. 12, Ecological Society of America, Washington, DC.
Comiskey, Jane Curnutt, John, Gross, Louis, 1998, ATLSS Snail Kite Index Model - Basic Model Description: The Institute for Environmental Modeling, University of Tennessee, Knoxville, TN.Online Links:
Bennetts, R. E. Collopy, M. W., Rodgers, Jr, 1994, The snail kite in the Florida Everglades: A food specialist in a changing environment: St. Lucie Press, Delray Beach, FL.
Davis, S. M. And Ogden, J. C, eds.
Bennetts, R. E. Kitchens, W. M., Dreitz, V., 2002, Influence of an extreme high-water event on survival, reproduction, and distribution of Snail kites in Florida: Wetlands v. 22, Society of Wetland Scientists, McLean, VA.
Mooij, W. M. Bennetts, R. E., DeAngelis,, 2002, Exploring the effect of drought extent on the Florida Snail Kite: interplay between spatial and temporal scales: Ecological Modelling v. 149, issues 1&2, Elsevier Science BV, Amsterdam, Netherlands.
Dreitz, V. J. Nichols, J. D., Hines, J. E, 2002, The use of resighting data to estimate the rate of population growth of the Snail Kite in Florida: Journal of Applied Statistics v. 29, n. 1-4, Routledge (Taylor & Francis Group), Abingdon, Oxfordshire, UK.Online Links:
Dreitz, V. J. Bennetts, R. E., Toland, B., 2001, Spatial and temporal variability in nest success of Snail Kites in Florida: The Condor v. 103, issue 3, The Cooper Ornithological Society, California.
Bennetts, R. E. Link, W. A., Sauer, J. A., , 1999, Factors influencing counts in an annual survey of Snail Kites in Florida: The Auk v. 116, The American Ornithologists' Union, McLean, VA.
Bennetts, R. E. Dreitz, V. J., Kitchens, W., 1999, Annual survival of Snail Kites in Florida with comparisons between radio telemetry and capture-resighting data: The Auk v. 116, The American Ornithologists' Union, McLean, VA.
Bennetts, R. E. Kitchens, W. M., 1999, Within-year survival patterns of Snail Kites in Florida: Jouranl of Field Ornithology v. 70, Association of Field Ornithologists, Lawrence, KS.
Bennetts, R. E. Golden, K., Dreitz, V. J., , 1998, Estimates of the proportion of Snail Kites attempting to breed and the number of attempts per year in Florida: Florida Field Naturalist v. 26, Florida Ornithological Society, Gainesville, FL.
Bennetts, R. E. Shannon, M. R., Kitchens, W, 1998, Causes of mortality of post-fledgling juvenile and adult Snail Kites in Florida: Florida Field Naturalist v. 26, Florida Ornithological Society, Gainesville, FL.
Valentine-Darby, P. E. Bennetts, R. E., Kitchens, , 1998, Seasonal patterns of habitat use by Snail Kites in Florida: Journal of Raptor Research v. 32, Raptor Research Foundation, Hastings, MN.
Bennetts, R. E. Kitchens, W. M., 1997, Population dynamics and conservation of Snail Kites in Florida: the importance of spatial and temporal scale: Colonial Waterbirds v. 20, The Waterbird Society, DeLeon Springs, FL.
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352 392-1861 (voice)
352 846-0841 (FAX)
kitchensw@wec.ufl.edu
snail knite monitoring data
No warrantees are implied or explicit for the data
Contact Wiley Kitchens for data and information for this project.
727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
sofia-metadata@usgs.gov
U.S. Department of the Interior, U.S. Geological Survey, Center for
Coastal Geology
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