Grantee Research Project Results
1999 Progress Report: Environmental Factors That Influence Amphibian Community Structure and Health as Indicators of Ecosystems
EPA Grant Number: R825867Title: Environmental Factors That Influence Amphibian Community Structure and Health as Indicators of Ecosystems
Investigators: Beasley, Val , Richards, Carl , Johnson, Lucinda , Piwoni, Marvin , Schoff, Pat , Cole, Rebecca
Current Investigators: Beasley, Val , Richards, Carl , Schotthoefer, Anna , Lieske, Camilla , Johnson, Catherine , Murphy, Joe , Johnson, Lucinda , Piwoni, Marvin , Schoff, Pat , Cole, Rebecca
Institution: University of Illinois Urbana-Champaign , USGS National Wildlife Health Center , Illinois Waste Management and Research Center , University of Minnesota - Duluth
Current Institution: University of Illinois Urbana-Champaign , Illinois Waste Management and Research Center , United States Geological Survey , University of Minnesota - Duluth
EPA Project Officer: Packard, Benjamin H
Project Period: June 1, 1998 through May 31, 2001 (Extended to September 30, 2002)
Project Period Covered by this Report: June 1, 1998 through May 31, 1999
Project Amount: $1,299,991
RFA: Ecosystem Indicators (1997) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:
The overall goal of this research is to assess the relative influence of landscape patterns, biotic interactions, water quality, and contaminants on the health and community structure of amphibians. Objectives are to evaluate: (1) the relative influence of wetland- and watershed-scale factors (i.e., landscape and ecological data) on amphibian community structure and health; and (2) whether amphibian community structure and health are indicative of ecological integrity.
Progress Summary:
In the past year, we have expanded and analyzed data for our 64 Tier 1 sites. Tier 1 landscape-level spatial analyses were used to characterize fragmentation patterns, connectivity of habitat patches, and other landscape metrics of each watershed and for areas within 2 km and 10 km of each wetland. Intensive Tier 2 and Tier 3 studies are focusing on 20 of the Minnesota wetlands from Tier 1 assessments plus 16 new sites in the region, for a total of 36 wetlands. Calling surveys to assess species richness and general abundance were conducted three times in 1999 at all 64 Tier 1 wetlands and at all 16 new sites in April?July 1999. At the 36 sites, dipnet surveys identified macroinvertebrates to the lowest possible taxon in the field and recorded data on amphibian larvae and egg masses. Detailed dipnet surveys of macroinvertebrates in major subhabitats determined dominance and general abundance of different taxa. Tadpoles and gastropods were sent to the National Wildlife Health Center (NWHC) for parasitology studies. Species composition and relative abundance of plants were evaluated along transects through major vegetative communities. Spatial data were assembled from aerial photos and GIS analyses to assess wetland structure/function for each of the 64 Tier 1 sites, and are in final stages of preparation for the new sites. Soil, vegetation, and macroinvertebrate data will be analyzed with data on land use, wetland type, hydrologic regime, water quality, toxicants and other aquatic fauna.
Water and sediment samples were collected twice from each pond in 1999, stored on ice, and delivered to the laboratory within 2 days. More than 950 samples were collected, greatly exceeding the number promised in the grant (a single water sample per site). To date, pesticides, other organic contaminants, and heavy metals have been detected in water only at low concentrations. Of greater concern was nitrate at up to 21 ppm. Although 18 Hydrolab water quality sondes were deployed in Tier 3 wetlands to log dissolved oxygen, temperature and pH data, 11 of the units malfunctioned. All were returned to Hydrolab under warranty. Hydrolab has been asked to provide 18 additional sondes in order to deploy 36 units in 2000.
Of 560 frogs examined in our malformation survey in 1998, 61 were collected and processed to stain bone and cartilage. Eight were malformed, with two having asymmetries in the pelvis, and eight specimens had bones that were hyperplastic due to either disease or malformation. Also, several frogs had mineralized areas in the body cavity wall. Other specimens are in the process of clearing and will be counterstained to allow skeletal visualization.
Amphibians were collected for Tier 3 studies in June?August 1999, and delivered to the NWHC for parasitology or the University of Illinois for pathology studies. Species besides Rana pipiens were accepted, because at some sites no R. pipiens were found. Frogs were euthanatized with an anesthetic, and body weight, length, sex, Gosner stage, and abnormalities in symmetry, pigmentation, spine, face, and limbs were recorded. Parasites identified included: Echinostoma spp., Rhabdias ranae, Haematolechus sp., Megalodiscus sp., and Ribeiroia sp. Echinostoma spp. were found in kidneys of frogs from all sites at prevalences of 40?100 percent (mean 82%) and intensities of 8?321 echinostomes per frog (mean 90). Among malformations were webbed skin between the femur and tibio-fibula, skin lacking spots, and hemimely (partial absence) of the hindlimb. For pathology studies, frogs from 30 sites were collected: no frogs were found at 6 sites. Euthanatized frogs were examined for abnormalities in symmetry, condition, eyes, tympanum, skin, muscles, skeleton, body cavity, liver, spleen, kidneys, gastrointestinal (GI) tract, lungs, reproductive tract, and central nervous system (CNS). Tissues were fixed in formalin. Of these frogs, 83 percent were R. pipiens, 12 percent were R. septentrionalis, 3 percent were R. clamitans melanota, and 1 percent were R. sylvatica. Overall, 50 percent were female and 42 percent were male. Intersex was identified in 6 percent of all frogs (from 11 sites). At two sites, 25 percent were apparently intersex frogs. Malformations and deformations were rare and included mandibular hypoplasia, brachymely (shortening) of the hindlimb, polymely (mirror image triplicate of the forelimb), hemimely of hindlimbs, and ectromely (missing limb) of a forelimb. Scar tissue often suggested previous trauma. At least one lesion was identified in 55 percent of frogs. Included were inflammation (42%), parasitism (29%), and trauma (11%). Condition scores from slightly poor to emaciated were noted in 8 percent of frogs from 12 sites. Parasitism was noted in the body cavity, GI tract, kidney, liver, lung, muscle, and skin. Inflammation in the body cavity involved ascites, fibrin tags, and adhesions. In skin, trauma involved lacerations, ulcerations, subcutaneous hemorrhage, and scar tissue. Musculoskeletal trauma involved fractures, torn muscles, and joint hemorrhage. Three percent had lesions potentially due to capture. The most common abnormality for body cavity, kidney, liver, and lung was inflammation (52?84%); for GI tract was no digesta (50%); for musculoskeletal system was trauma (52%); and for spleen was splenomegaly (73%). Diagnoses and sex determinations will be confirmed histologically.
Future Activities:
In coming months, we will be completing examinations of metamorphs, identifying parasites, completing histopathology studies, entering all health data, and completing chemical analyses from the 1999 field season. Also, we will collect additional ecological, water quality, contaminant, and anuran community structure and health data for 2000, and collect additional data based on aerial photo-interpretation and detailed digital databases. Statistical analyses and report generation will continue.
Journal Articles:
No journal articles submitted with this report: View all 47 publications for this projectSupplemental Keywords:
water, watersheds, sediments, exposure, ecological effects, animal, sex, chemicals, toxics, heavy metals, organics, pathogens, ecosystem, indicators, aquatic, habitat, integrated assessment, ecology, epidemiology, pathology, remote sensing, analytical, LANDSAT, satellite, modeling, Midwest., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, Microbiology, Ecological Risk Assessment, Biology, Ecological Indicators, ecological exposure, pesticide exposure, aquatic biota , landscape indicator, watersheds, amphibians, ecosystem integrity, parasitic infection, multiple spatial scales, biotic integrity, contaminant impact, water qualityRelevant Websites:
http://www.nrri.umn.edu/cwe/amphweb.html
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.