Fall 2002 Conservation Perspectives: Drainage to Dragonflies: boxes and tables accompanying artice

Box 1: Human Impacts on Stream Fauna

Sprawling development is likely the greatest threat to the physical, chemical, and ecological balance of small streams today. The following is a list of several major direct and indirect negative impacts on aquatic biodiversity due to the conversion of forests and pastures to roads, lawns, and buildings.

Deforestation: Removal of trees from riparian zones reduces coarse organic input, reduces shade cover, decreases water retention and increases erosion.
Storm water runoff: Sediment deposition and bank erosion caused by storm water discharge from roads and other impervious surfaces can drastically alter the composition and stability of benthic substrates. Runoff may also significantly increase water temperature and salinity of small streams.
Pesticides: Many pesticides commonly used in the control of mosquitoes, midges, and lawn grubs are general insecticides that kill more than just the target species; often an entire order is harmed. For example, Bti is lethal to many aquatic Diptera* (true flies) (EPA 2000), and may be a threat to endangered aquatic insects; Methoprene is deadly to all arthropods. Widespread use of insecticides may also have serious consequences for organisms higher in the food chain, including dragonflies, fish, and birds.
Nutrient loading: Increased nutrient levels from septic systems and fertilizer applications can overstimulate plant and algae growth, negatively affecting stream habitat conditions such as water velocity, substrate quality, and dissolved oxygen levels.
Water draw-down: The reduction in precipitation infiltration combined with increased human demand for fresh water results in altered streamflow. Although reductions in water levels may create more potential habitat for rare organisms adapted to semi-permanent stream conditions, a significant decrease in continuous-flow habitats likely represents a more serious threat to overall diversity.

* Craneflies (Tipulidae), one of the most species-diverse families of aquatic insects worldwide (Pritchard 1983) and virtually harmless to humans, may be susceptible to Bacillus thuringiensis israelensis (Bti), a bio-pesticide widely used to control mosquito populations.

Box 2. Recent developments in aquatic invertebrate conservation for Massachusetts

1. Habitat Surveys. Stream Teams and local watershed organizations (see the Executive Office of Environmental Affair’s Watershed Coalition (http://www.commonwaters.org/) are using the help of volunteers and staff to take flow measurements, water samples, and collect macroinvertebrates in streams and rivers. Another excellent example of aquatic habitat documentation in Massachusetts is the survey of potential vernal pool sites that was carried out by the MNH&ESP (Burne 2000). Work done with existing maps and aerial photographs should be followed up with ground-based field studies.

2. Aquatic Macroinvertebrate Adult and Larval Surveys. As a result of a four-year study of the North River and its tributaries (F. SaintOurs, Master’s thesis), eight dragonfly species, all associated with running water, were added to the Plymouth County Odonata list. All but one (L. vernalis) were discovered only through adult surveys and were not found in benthic samples, suggesting that using both approaches would be advantageous in large-scale impact or conservation assessments using aquatic invertebrates. The Department of Environmental Protection and the Natural Heritage Program have also initiated statewide aquatic invertebrate inventories.

3. Databases. Statewide databases for freshwater invertebrates (Chandler 2001, for example) are instrumental in determining rare, threatened, and possible indicator species. Making this information accessible to the public on the World Wide Web would be a tremendous advancement in conservation science.

4. Dragonfly Counts. A “Fourth of July” dragonfly census was initiated in Hanover, MA on June 27, 2001 where more than 25 species were identified and counted during a four-hour walk. On June 30, 2002 the census was repeated, with a total count of 35 species. Annual Odonata inventories should also include a Memorial Day and Labor Day census to account for early and late-season species.

5. Odonata Publications and Lists. Recently established regional newsletters and email list-servers available via the World Wide Web have improved the science of Odonatology in Massachusetts and throughout the World. (see Internet Resources section).

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Table 1. State-listed and other potentially threatened insects found in streams and rivers of Plymouth County, Massachusetts.

DRAGONFLIES
Species	Year added	Status	Ecology	Flight period
Spine Crowned Clubtail Gomphus abbreviatus Hagen in Selys 1878	2001	E	River rapids, forest clearings	June-July, 10am-4pm
Umber Shadowdragon Neurocordulia obsoleta (Say 1839)	1998	SC	Rivers and reservoirs; exuviae found on dams and bridges. Flies at dusk	June-July, 8-8:45pm
Mocha Emerald Somatochlora linearis (Hagen 1861)	2001	SC	Forest streams, meadows. Seen in clearings after rain	July-August, 9am-6pm
Arrowhead Spiketail Cordulegaster obliqua (Say 1839)	1998	W	Tiny, semi-permanent creeks. Semi-voltine.**	June-July, 10am-2pm
Southern Pygmy Clubtail Lanthus vernalis Carle 1980	1997	W	Small, shaded, perennial springs. Semi-voltine.**	May-June, 10am-2pm
-
OTHER INSECTS
Spiny Net-spinning Caddisfly Parapsyche (Trichoptera: Hydropsychidae)	1999	R	Small, shaded, perennial streams	Not known
Stripetail Stonefly Isoperla Banks (Plecoptera: Perlodidae)	1998	R	Small, shaded, perennial streams	April-May
Spring Minnow Mayfly Ameletus (Ephemeroptera: Ameletidae)	2001	O	Small, shaded, semi-permanent and perennial streams	May-June
False Water Penny Ectopria nervosa (Melsheimer) (Coleoptera: Psephenidae)	1999	O	Small, shaded, rocky-bottomed forest streams	June-July
Forest Dancefly Oreogeton (Diptera: Empididae)	1999	O	Small, shaded, perennial streams	Not known
-
R = rare, O = Occasional (SaintOurs 2000); E = endangered, SC = Special Concern (MNH&ESP); W = Watch List (MNH&ESP) **Semi-voltine species require two or more years for larval development.

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Box 3. Additional stream insects to monitor

Periodically collected and reported information on non-listed species would make a significant contribution to conservation efforts. The following is a list of dragonflies and other aquatic insects that are known to be specialists of stream and river habitats of eastern Massachusetts.

DRAGONFLIES

Delta-Spotted Spiketail Cordulegaster diastatops (Selys) (Fig. 3B). Found near forest streams, seems to prefer somewhat less-disturbed places than C. maculata.
Twin-Spotted Spiketail Cordulegaster maculata Selys (Fig. 3C). The most common Spiketail in the area, inhabiting disturbed and undisturbed perennial streams.
Stream Cruiser Didymops transversa (Say). Streams and rivers; exuviae can often be found on bridges and other constructions next to waterways.
Dragon Hunter Hagenius brevistylus Selys. Our largest Clubtail; found in large, sandy-bottomed streams.
Illinois River Cruiser Macromia illinoiensis Walsh. Rivers and lakes.

OTHER INSECTS

Riffle Beetles Ancyronyx variegata, Machronychus glabratus, Dubiraphia sp., Oulimnius sp., Optioservus sp., Promoresia sp. (Coleoptera: Elmidae). Found in a variety of perennial streams, especially in gravel and cobble-bottomed riffle areas.
Water Penny Psephenus herricki (Coleoptera: Psephenidae). Found chiefly in middle to lower reaches, among cobble and boulders in swift currents.
Common Stoneflies Perlesta (Plecoptera: Perlidae). Found in middle to lower reaches; emergence occurs in late summer.
Flathead Mayflies Stenonema (Ephemeroptera: Heptageniidae). Found in perennial streams with swift currents.
Spiny Crawler Mayflies Ephemerella and Eurylophella (Ephemeroptera: Ephemerellidae). Found in perennial streams; less common than Flathead Mayflies.
Craneflies (Diptera: Tipulidae). A diverse group of harmless flies that may be adversely affected by the widely used biopesticide Bti.

Drainage to Dragonflies: Conservation of Aquatic Invertebrates in Rivers and Streams of Eastern Massachusetts

Boxes and Tables Accompanying Article

by Frederick H. SaintOurs
Department of Biology, University of Massachusetts Boston

Box 1: Human Impacts on Stream Fauna

Box 2. Recent developments in aquatic invertebrate conservation for Massachusetts

Table 1. State-listed and other potentially threatened insects found in streams and rivers of Plymouth County, Massachusetts.

Box 3. Additional stream insects to monitor

Drainage to Dragonflies: Conservation of Aquatic Invertebrates in Rivers and Streams of Eastern Massachusetts

Boxes and Tables Accompanying Article

by Frederick H. SaintOurs Department of Biology, University of Massachusetts Boston

Box 1: Human Impacts on Stream Fauna

Box 2. Recent developments in aquatic invertebrate conservation for Massachusetts

Table 1. State-listed and other potentially threatened insects found in streams and rivers of Plymouth County, Massachusetts.

Box 3. Additional stream insects to monitor

by Frederick H. SaintOurs
Department of Biology, University of Massachusetts Boston