William Loftus (retired) Joel Trexler (Florida International University) 2000 poster http://sofia.usgs.gov/projects/index.php?project_url=consume_comm The trophic ecology of Everglades fishes is poorly documented. In tropical-fish communities, hydrologic seasonality greatly affects patterns of food-resource use, such as local and long-range movements among habitats, seasonal changes in diets, diet specializations, the presence and seasonality of diet overlaps, etc. (Lowe-McConnell 1975; Winemiller 1989, 1990). We analyzed Everglades native and introduced fish diets to identify the most important invertebrate and plant prey, and to compare trophic positions of species within and among three habitats and two seasons (Fig. 1). We used the complementary techniques of stomach and stable isotope analysis for both instantaneous and time-integrated views of animal diets (Vander Zanden and Rasmussen 1996). We then compared diet patterns in the temperate Everglades fish community with those from seasonal aquatic systems in the tropics. We posed the following hypotheses in examining those patterns: 1: Herbivory and omnivory are common trophic states in the Everglades. 2: Seasonal changes in diets within a habitat are usual . 3: Specialization in diet is common; generalists are rare. 4: Diet overlap is highest during high-water periods when food is plentiful. This study is a first step in using data from across habitats and seasons for use in constructing a empirical food web for the Everglades marsh. In modeling the dynamics of aquatic animal populations in southern Florida wetlands, the dispersal distances, rates of movements, and timing of movement are important but poorly understood. The small size of the wetland animals precludes the use of standard marking techniques for studying movement, and the large, open system of these wetlands makes recapturing marked animals improbable. Genetic markers, used to determine population structure, offer an indirect way of assessing the degree of movement and mixing in these populations, and the landscape-level patterns of animal movement. In a series of studies in this multi-year project, our objectives are to identify population structure of selected aquatic species in the Everglades and to estimate migration rate from genetic data on gene flow for incorporation in the ATLSS model. Data from studies on whether levee and canal systems act as barriers to dispersal of aquatic animals in the Everglades are applicable to the Restudy. We are also using genetic techniques to learn if populations of introduced Asian Swamp Eels have the same source of origin, thereby establishing whether new collection locations represent dispersal events or new introductions. 1977 1997 ground condition Complete None planned -81.25 -80.3 25.75 25 none modeling biology fish aquatic animals hydroperiods ISO 19115 Topic Category biota environment inlandWaters 002 007 012 Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, DC, National Institute of Standards and Technology United States US U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, DC, NIST Florida FL Department of Commerce, 1990, Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas, FIPS 6-3, Washington, DC, National Institute of Standards and Technology Miami-Dade County Broward County USGS Geographic Names Information System Everglades National Park none Central Everglades ENP none none Joel Trexler Florida International University, Department of Biological Sciences mailing address

11208 S.W. 8th Street

Miami FL 33199 USA 305 348-1966 305 348-4032 trexlerj@fiu.edu We could not have completed this study without the efforts of Victoria Foster and Jennifer Rehage, who assisted in summarizing the raw data for analysis and in preparing the report and poster. Tom Atkeson, FL Department of Environmental Protection, provided funds that helped to complete the analysis. Adams, S. M. Kimmel, B. L.; Plosky, G. R. 1983 report Canadian Journal of Fisheries and Aquatic Sciences v. 40, n. 9, p. 1480-1495 Ottawa, Ontario, Canada National Research Council Canada accessed as of 11/8/2010 The full article is available via journal subscription or single article purchase. The abstract may be viewed on the website below http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=eng&journal=cjfas&volume=40&year=0&issue=9&msno=f83-170 Lowe-McConnell, R. H. 1975 book New York, NY Longman, Inc Vander Zanden, M. J. Rasmussen, J. B. 1996 report Ecological Monographs v. 66, n. 4, p. 451-477 Washington, DC Ecological Society of America accessed as of 11/8/2010 The full article is available via journal subscription or single article purchase. The abstract may be viewed on the website below http://www.jstor.org/pss/2963490 Winemiller, K. O 1989 report Environmental Biology of Fishes v. 26, n.3, p. 177-199 Dordrecht, The Netherlands Springer Netherlands accessed as of 11/8/2010 http://www.springerlink.com/content/m43267581g4g7139/fulltext.pdf Winemiller, K. O. 1990 report Ecological Monographs v. 60, n. 3, p. 331-367 Washington, DC Ecological Society of America accessed as of 11/8/2010 The full article is available via journal subscription or single article purchase. The abstract may be viewed on the website below http://www.esajournals.org/doi/abs/10.2307/1943061 Winemiller, K. O. 1996 book chapter New York, NY Chapman and Hall in Food Webs: Integration of patterns and dynamics, G. A. Polis and K. O. Winemiller, eds Each species was separated into arbitrarily chosen size-groups of ~ 25 fish; length and wet mass recorded. Approximately 4000 specimens of 26 native fishes collected by rotenone, nets, angling, and electrofishing from 1977-1981 were supplemented by 6 introduced species during 1995-1997. Approximately 4,000 specimens of 26 native fishes collected by rotenone, nets, angling, and electrofishing from 1977-1981 were supplemented by 6 introduced species during 1995-1997. Each species was separated into arbitrarily chosen size-groups of ~ 25 fish; length and wet mass recorded. Volumes were measured to 0.001ml using a blood-sedimentation tube; volume of digested prey not reconstructed; The small size of food items required the pooling of like items from each size-class of fish for volumetric analysis. Trophic Classification We grouped fishes into 5 Trophic Classes using continuous scores (tau symboli ) based on sums of prey scores, multiplied by the proportion of diet comprised by each prey type (Adams et al. 1983; Winemiller 1990). 1 = Mainly Herbivorous, >50% plant material (Score = 1.0 -1.74); 2 = Omnivorous, 25-50% plant material (Score = 1.75-2.19); 3 = Omnivorous, <25% Plant material (Score = 2.20-2.74); 4 = Omnivorous, mostly animal prey (Score = 2.75-2.99); 5 = Predominantly carnivorous, fish and decapods (Score = >3.0). The results were used to identify the most important invertebrate and plant prey and to compare trophic positions of species among and within 3 habitats (alligator pond, spike rush, and sawgrass) and two seasons (high-water and low-water periods). 2000 Joel Trexler Florida International University, Department of Biological Sciences mailing address

11208 S.W. 8th Street

Miami FL 33199 USA 305 348-1966 305 348-4032 trexlerj@fiu.edu 20101108 Heather Henkel U.S. Geological Survey mailing and physical address

600 Fourth Street South

St. Petersburg FL 33701 USA 727 803-8747 ext 3028 727 803-2030 sofia-metadata@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 none The principal investigator for this project retired and the Point of Contact has declined to provide a review of the information in the metadata record. Any questions about the information should be directed to the Point of Contact under Citation Information or the Process Contact(s). This metadata record may have been copied from the SOFIA website and may not be the most recent version. Please check http://sofia.usgs.gov/metadata to be sure you have the most recent version.