Earthwatch

Abstract:

Our Team is currently studying insect assemblages in aquatic ecosystems in Ohio, Oregon, and Texas (Figure 1). We use portable light traps to collect adult insects in a variety of aquatic ecosystems (lakes, rivers, streams, springs, bogs, fens, marshes, wooded wetlands, etc.) and in adjacent upland sites. Vegetation and water chemistry are also measured. All collected insects are sorted to order, several groups of insects (e.g., Trichoptera and Diptera) are identified to a lower level of taxonomic resolution. A data matrix is then constructed from the insect collection results and an ordination performed. Ordination is a descriptive statistical technique that uncovers patterns in large, complex data sets. Ordination results are then correlated to vegetation and environmental data in order to determine those factors that are related to the observed patterns in insect assemblages.

We have demonstrated that specific wetland cover types have distinct insect populations. These populations appear to be driven, in part, by differences in the structure and composition of the wetland plant community. Other wetland features, such as hydrodynamics and water quality, probably also play a role.

This work is important because it makes use of organisms that are highly dependent upon environmental conditions of aquatic ecosystems. For example, Trichoptera (caddisflies) is a largely aquatic order; in order to survive, the larvae depending on long-term (> 6 mo.) patterns in water quality and perhaps in aquatic ecosystem structure and function. This research is important to resource managers since caddisflies, as well as other insects, are generally not directly manipulated by nature preserve managers and those interested in restoring or constructing wetlands, as are many plant populations. Therefore, insects may serve as an integrative measure of the integrity and function of aquatic ecosystems. Information gathered during this study will add to the knowledge of the distribution of insects in North America (we have collected several new species of caddisflies in Big Bend National Park and we have documented range extensions for other species).

Volunteers are important to the success of our research. Typically, volunteers assist in setting up and taking down light traps, identifying and counting collection material, running vegetation transects, data entry and analysis. Since one of the goals of this research is to develop a bioassessment tool, we are particularly interested in how people of different backgrounds learn how to use our techniques.

1. Aquatic Ecosystems in Big Bend National Park

(14 June - 1 July 1998)

More Information

Research Site: Big Bend National Park: Glenn Springs, Boot Springs, Rio Grande, and Cattail Falls.  We will also be collecting data at one of our sites that will be used to guide a wetland restoration effort in the park.

Team Dates in Field: 14 June - 1 July 1998 (one week teams available)

Min/ Max # of Volunteers: 10/25

Welcome Letter to Earthwatch Volunteers

Meet Mrs. Gienger, High School Teacher and leader of a virtual field trip to Big Bend National Park.

Study Objectives:

1. To inventory positively phototaxic insect orders at selected aquatic sites in Big Bend National Park in order to determine if there are differences in the insect assemblages at those sites;
2. To inventory insects at selected aquatic sites in Big Bend National Park in order to determine if there are new species or previously unreported species of caddisflies;
3. To determine if each of these aquatic ecosystems has a characteristic assemblage of insects (or caddisflies) that can be used as a 'biological target' or 'biological signature';
4. To relate insect assemblages to the structure and composition of wetland vegetation and to the physical environment.

For More Information Contact: The Center for Field Research P.O. Box 403  680 Mount Auburn St.  Watertown, MA 02272

Site Map   150 k

Regional Map   50 k

2. Aquatic Ecosystems of the Tundra

(26 August - 10 September 1998)

Research Sites: Lakes and wetlands around the Churchill Northern Studies Centre.

Team Dates in Field: 26 August - 10 September 1998 (one week teams available)

This Trip is being offered in conjunction with an Arctic Ecology Course (details).
 
 

	Churchill, Manitoba   The Churchill Northern Studies Center, at Churchill Manitoba, is located near the Hudson Bay coast where the Taiga meets the Tundra.  Within a few minutes travel from the center are examples of spruce dominated taiga, dry old beach areas, meadows and wetlands dominated by birch and willow shrubs, many shallow ponds, arctic streams, sedge meadows, moss and lichen      dominated lowlands and salt marshes along the Hudson Bay.
	Volunteers will spend a great deal of time walking to and from the study sites. Most of the area is underlayed by permafrost. The weather in  August- September is unpredictable.  The area is wet and appropriate food wear is required.   Average temperatures range from 7.2-15.3 C in August and 2.2-8.5 C in September.  Average rainfall is 58.3 mm in August and 44.5 mm in September.
	The greatest danger for field teams are polar bears.  Each fall polar bears congregate in the Churchill area waiting for Hudson Bay to freeze.  Black flies may be abundant on warmer days during the fall months.

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