Grantee Research Project Results
2001 Progress Report: Effects of Interacting Stressors in Agricultural Ecosystems: Mesocosm and Field Evaluation of Multi-level Indicators of Wetland Responses
EPA Grant Number: R826595Title: Effects of Interacting Stressors in Agricultural Ecosystems: Mesocosm and Field Evaluation of Multi-level Indicators of Wetland Responses
Investigators: Threlkeld, Stephen , Crain, Andrew , Ochs, Clifford , Schlenk, Daniel , Easson, Greg , Slattery, Marc , D'Surney, Stephen , Britson, Carol
Current Investigators: Threlkeld, Stephen , Benson, William H. , Crain, Andrew , D'Surney, Stephen , Easson, Greg , Ochs, Clifford , Schlenk, Daniel , Slattery, Marc
Institution: University of Mississippi , University of California - Davis
Current Institution: University of Mississippi
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Period Covered by this Report: October 1, 2000 through September 30, 2001
Project Amount: $897,634
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
Our primary objective is to evaluate indicators of molecular, cellular, population, community, and ecosystem responses to multiple, potentially interacting, natural, and anthropogenic stressors that vary at different spatial and temporal scales in agricultural wetlands. The indicators were chosen to represent a selection of mechanism-based and system-level integrative characteristics that might be amenable to cost-effective routine monitoring. Our null hypothesis is that indicators that effectively characterize ecosystem responses to single stressors are also scale- and interaction-independent (i.e., useful even when there are multiple, interacting stressors with diverse operational scales). Our alternative hypothesis is that when multiple, interacting stressors are present, responses are not well characterized by indicators that are useful for monitoring the effects of single stressors. This outcome demands the use of either a different set of indicators or a different spatial or temporal scale of resolution for evaluating the indicators. The indicators will be examined first in a set of 72 wetland mesocosms where individual and multiple, interacting stressors are used as treatments in a controlled outdoor experiment. Postexperiment analysis will focus on the efficacy of each indicator to discriminate among different stressors or combinations of stressors. Successful indicators will then be evaluated in agricultural wetlands identified by analysis of northern Mississippi agricultural landscapes, based on remote imagery and other landscape data, to have the same stressors or combinations of stressors present that were included in the mesocosm experiment.Progress Summary:
In the past project year, our efforts have focused on three areas: (1) intensive sampling of randomly selected wetlands within the Little Tallahatchie River Basin; (2) continuation of mapping and GIS development incorporating data collected from the field; and (3) analysis of data collected during the experimental, mesocosm phase of the previous project year. We discuss particulars of each effort and details of future activities below. During the past year we requested, and were granted, a no-cost extension for the project to allow more time for data analysis and report preparation. As such, the present document is an annual, rather than final, report.Field Sampling Effort: Our research efforts in the field have been
focused on: (1) contacting
landowners requesting access to their property;
(2) assessing suitability of potential sampling sites once access has been
granted; and (3) sampling a suite of endpoints from several levels of biological
organization at acceptable sites. Data from field sampling will be incorporated
in a multivariate analysis that includes data from our previous year's mesocosm
experiment to examine scale dependency?both spatially and temporally?across the
levels of biological organization.
Information packets were sent to each landowner of an agricultural (pesticide-impacted) or nonagricultural pond that met selection criteria. A brief review of selection criteria is as follows: selection of ponds within agricultural sections (by township, range, and section according to the Public Land Survey [PLS] system) was done by assigning a random number to each pond and then selecting the first five ponds per section for which there was ownership data (as obtained through county Farm Services Agency offices). Selection of ponds from sections not impacted by agriculture began with the random selection of up to 25 sections from each of the seven major geologic units across the basin. A random number previously assigned to all ponds was then used to select the first five ponds from each of these sections. Ownership information for nonagricultural ponds was obtained through county tax assessor records.
Information packets included a letter of introduction, personalized color-maps that indicated both location and pond(s) for which we were requesting access, and statements of authorization. Access was granted when the landowner signed the authorization statements and returned a copy to us. Information packets were sent to owners of 103 agricultural and 408 nonagricultural ponds across the study basin. Replies were received for 76 of the agricultural ponds and 230 on the nonagricultural ponds. Positive responses (permission granted) were received for 75 percent (57 of 76) of the agricultural ponds and 84 percent (194 of 230) of the nonagricultural ponds. Agricultural ponds were coded according to the potential pesticide load for the four pesticides of interest: chlorpyrifos, methyl parathion, atrazine, and MSMA (monosodium methanearsonate). Eight of the 17 combinations of these pesticides can physically occur in the real world as determined by crop and pest types for which the pesticide(s) were produced. Of those eight, our randomly selected ponds represented five of the combinations. There were no ponds existing on properties with the other three combinations. Access was granted for ponds from the five combinations.
Onsite visits were conducted at each pond for which access was granted. Site
visits took place from November 2000, through March 2001, and allowed us to
determine suitability of each site for sampling. Pond location (latitude and
longitude) was verified with a hand-held global positioning system. Positive
verification was necessary, as we were visiting only a small fraction of the
available ponds in the study basin (251 out of more than 8,700). Once location
was verified, the following information was collected: present condition of the
pond (i.e., ability to retain water); upstream and downstream land use (i.e.,
crops, active/inactive livestock pasture, timber, etc.); proximity to
residential houses (i.e., septic systems), proximity to illegal garbage dumps;
proximity to other selected ponds (e.g., two or more ponds on the same property
may be located in the same drainage pattern); and ease of access (i.e., distance
from nearest navigable road, hiking conditions to pond, etc.). Ponds were
removed from consideration if they received residential waste, drained directly
into another selected pond, were more than a 30-minute hike from a road or path,
or did not hold water. Of the ponds for which access was granted, 41
agricultural ponds and 103 nonagricultural ponds were determined to be suitable
for sampling.
Sampling of ponds took place from March to August 2001.
Postcards were sent to landowners 1 week prior to the scheduled sampling date
for their pond(s). This form of communication significantly enhanced our rapport
with the landowners. Ponds were scheduled for sampling so as to achieve a
diverse group of ponds for each week (i.e., agricultural and nonagricultural
ponds across varying geologic formations). Ponds were visited by a team of
project personnel (e.g., C.A. Britson and 1-2 student technicians) on each of 2
consecutive days. On the first day, ambient and water conditions were recorded,
and all water, sediment, zooplankton, vegetation, and seine/dipnet samples were
collected. Text descriptions and digital photos also were recorded on the first
day. Minnow, crawfish, and a variety of turtle traps were baited and set on the
first day to passively sample macroinvertebrate, fish, amphibian, and reptile
communities. Additional financial support for turtle trapping (i.e., cost of
nets, bait, mileage, etc.) was provided by the Mississippi Wildlife Heritage
Fund as part of their efforts to locate alligator snapping turtles (Macroclemys
temminckii) in selected river basins in the state. Data loggers also were
deployed on the first day to obtain a 24-hour water temperature cycle at
5-minute intervals. On the second day, all traps and data loggers were
removed.
A total of 101 ponds were visited during the sampling season. Samples and endpoints (Table 1) correlated with the endpoints measured from our previous year's mesocosm experiment. This correlation is critical to the testing of our null hypothesis, which states that indicators that effectively characterize ecosystem responses to single stressors also are scale- and interaction-independent (i.e., useful even when there are multiple, interacting stressors with diverse operational scales). Analysis of field data and multivariate statistical analyses of all data taken across the various spatial and temporal scales will begin in October 2001. Pond-specific reports of data collected will be sent to all landowners in December 2001.
Mapping and GIS Effort: Current mapping activities consist of
detailing local conditions in the area surrounding each of the 101 ponds that
were sampled. Activities include evaluating factors that influence water flow
and quality into each pond as well as natural conditions that may affect species
migration to and from each pond. The up-gradient extent of analysis consists of
the pond's watershed. Watershed characterization includes factors such as
agricultural occurrence (crop type and acreage), general land use (grass, trees,
roads, gravel, bare soil, etc.), residential or urban land use, and industrial
land use. The down-gradient area, which does not contribute to the watershed,
also is being characterized for evaluation of factors not restricted by the
movement of surface water such as animal migration. Data sets used for this
activity include: (1) digital elevation models of the study basin, USGS 30 meter
DEM data; (2) Landsat 7 imagery
collected from multiple dates in the 1999
growing season; and (3) 1998 and 1999 Farm Service Agency crop data. Upon
completion of the characterization of the watershed area affecting each pond,
biological sampling data will be combined with this information and analyzed for
interactions. These interactions will be used in the development of a conceptual
model of interaction in agricultural ecosystems.
Table 1. Summary of samples taken,
endpoints measured, and current data status at 101 wetland sites in the Little
Tallahatchie River Basin, Mississippi. Researcher initials stand for those
personnel (investigators and graduate stu-dents) responsible for the particular
assay(s). | |||||
Sample |
Endpoint and Units (where
applicable) |
Investigator |
Sample Processed |
Data Collected |
Data Entry |
ambient conditions |
temperature (C) |
CB |
completed |
completed |
completed |
relative humidity (%) |
CB |
completed |
completed |
completed | |
water conditions (onsite) |
dissolved oxygen (mg/l) |
CB |
completed |
completed |
completed |
temperature (C) |
CB |
completed |
completed |
completed | |
250 mL sediment |
sediment pH ([H]) |
PS |
completed |
completed |
completed |
500 mL water |
pH ([H]) |
CB |
completed |
completed |
completed |
turbidity (NTU) |
CB |
completed |
completed |
completed | |
Phenolphthalein-alkalinity (ppm
CaCO3) |
CB |
completed |
completed |
completed | |
Total-alkalinity (ppm CaCO3) |
CB |
completed |
completed |
completed | |
4 L water |
primary productivity |
CO,FO |
completed |
completed |
in progress |
bacterial productivity |
CO,FO |
completed |
completed |
in progress | |
DOC |
CO,FO |
completed |
completed |
in progress | |
TP |
CO,FO |
completed |
completed |
in progress | |
light extinction coefficient |
CO,FO |
completed |
completed |
in progress | |
TN |
CO,FO |
completed |
in progress |
in progress | |
CHNS |
CO,FO |
completed |
in progress |
in progress | |
pigments |
CO,FO |
completed |
in progress |
in progress | |
chlorophyll a |
CO,FO |
completed |
in progress |
in progress | |
suspended sediments |
CO,FO |
completed |
in progress |
in progress | |
temperature logger |
water temp at 5 min intervals
(C) |
CB |
completed |
87/101 |
completed |
zooplankton sample |
community description |
ST |
completed |
in progress |
in progress |
vegetation transect |
categorical vegetation description at -1, 0, 1, 5, and > 5 m from shore |
CB |
completed |
completed |
completed |
50 m perimeter walk/site
description |
site description, owner info, frogs calling,
etc. |
CB |
completed |
completed |
completed |
seine/dipnet captures |
count of fish, reptiles, amphibians,
inverts |
CB |
completed |
completed |
completed |
minnow trap captures (fish) |
age category |
CB |
completed |
completed |
completed |
species |
CB |
completed |
completed |
completed | |
crawfish trap captures (fish) |
age category |
CB |
completed |
completed |
completed |
species |
CB |
completed |
completed |
completed | |
crawfish trap captures (hatchling /juvenile turtles) |
species |
CB |
completed |
completed |
completed |
gender (M/F/J) |
CB |
completed |
completed |
completed | |
mass (g) |
CB |
completed |
completed |
completed | |
length (mm) |
CB |
completed |
completed |
completed | |
turtle trapping (3' diameter hoop nets of varying mesh and opening sizes) |
species |
CB |
completed |
completed |
completed |
gender (M/F/J) |
CB |
completed |
completed |
completed | |
mass (g) |
CB |
completed |
completed |
completed | |
length (mm) |
CB |
completed |
completed |
completed | |
Digital photos |
digital photos |
CB |
completed |
in CD format |
NA |
Trachemys scripta
(male) |
digestive efficiency of
turtles |
SS |
completed |
completed |
completed |
Gambusia affinis |
DNA strand breakage |
SD,PS |
in progress |
in progress |
in progress |
apoptosis (presence/absence) |
SD,PS |
in progress |
in progress |
in progress | |
RAPD |
SD,PS |
in progress |
in progress |
in progress | |
Rana sphenocephala eggs and
tadpoles |
DNA strand breakage |
SD,PS |
in progress |
in progress |
in progress |
apoptosis (presence/absence) |
SD,PS |
in progress |
in progress |
in progress | |
Lepomis macrochirus |
DNA strand breakage |
SD,PS |
in progress |
in progress |
in progress |
apoptosis (presence/absence) |
SD,PS |
in progress |
in progress |
in progress | |
RAPD |
SD,PS |
in progress |
in progress |
in
progress |
Mesocosm Experimental Effort: Univariate and multivariate analysis of data from our previous year's multiple stressor mesocosm experiment is underway. Rana sphenocephala metamorphs emerging from the mesocosms in 2000 were released into a drift-fence enclosed common pond. Surveys of pitfall trap captures revealed that these individuals have survived under enclosed conditions but had not reached reproductive maturity by spring of 2000. Assessment of survival and reproductive activity will continue through the spring of 2002.
Future Activities:
A conceptual model of interaction in agricultural systems will be developed based on characterization of the watershed area affecting each pond, biological sampling data, and interactions found when this information is combined and analyzed. Further investigation will be conducted to evaluate spatial or temporal scale dependencies of the model and how it can be used in both small watersheds and the overall study basin. This process may include the use of additional imagery most likely of a higher resolution than that available with Landsat 7.Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 33 publications | 3 publications in selected types | All 2 journal articles |
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Type | Citation | ||
---|---|---|---|
|
Easson GL, Robinson H. Using 30-meter resolution digital elevation data for basin analysis-a practical utilization of USGS 24K digital elevation data-complications and solutions. ArcUser 2001;4(3):26-28. |
R826595 (2001) R826595 (Final) |
not available |
Supplemental Keywords:
water, watersheds, scaling, metals, organics, genetics, molecular biology, remote sensing, monitoring, ecology, limnology, agriculture, organism, cellular, population, enzymes, MS., RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Ecology, Limnology, Ecosystem/Assessment/Indicators, Environmental Chemistry, Ecological Effects - Environmental Exposure & Risk, Agronomy, Watersheds, Ecological Indicators, anthropogenic stresses, ecological risk assessment, interactive stressors, remote sensing, UV effects, agricultural watershed, chlorpyrifos, enzymes, metal release, multiple spatial scales, multiple stressors, ecosystem indicators, field validation, mesocosm, aquatic ecosystems, environmental stress, water quality, stress responses, multiscale assessment, agriculture ecosystemsRelevant Websites:
http://www.olemiss.edu/projects/epa-eig/
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.