Choate vegetation management project


Somatochlora minor Ocellate Emerald Dragonfly



Download 0.73 Mb.
Page12/19
Date conversion14.06.2018
Size0.73 Mb.
1   ...   8   9   10   11   12   13   14   15   ...   19

Somatochlora minor Ocellate Emerald Dragonfly

This species is small (42-44 mm. total length), with two oval, yellow spots on the side of the thorax. Abdomen is short and lacks light colored markings after segment 3. The ovipositor of females is spout-like and perpendicular to the long axis of the abdomen (Dunkle 2000, Walker and Corbet 1975). Larvae are uniformly brown and not very hairy (Walker and Corbet 1975). This is a northern species, occurring across Canada and the northeast and Pacific Northwest in the United States. It is widespread across the Upper Peninsula and a Forest-wide survey (7/12/01-7/18/01) found them in Caddis Creek, Ontonagon county; and Wellington Creek, Gogebic County. Where found, it was associated with S. elongata. The habitat appears to be narrow, rocky, shady streams without emergent vegetation. They are also found in streams running through open sedge meadows. The adults feed in shady forest glades or along forest edges (Dunkle 2000). It is in sedge meadow habitats that it is most likely to be encountered with S. elongata. The larvae of the Genus Somatochlora are sprawlers, which means they live at the substrates surface or hidden amidst debris (Corbet 1999). They would require a microhabitat that contains some organic matter to hide in, such as depositional areas. Their diet is very broad and includes any animal small enough to capture and ingest. The flight season is early June or July to mid-august (Needham et al 2000).
There is potential habitat present; this species will be analyzed further.
Alternative 1 (No Action Alternative)

There would be no harvesting activities, no road construction, re-construction, maintenance, or decommissionsing of roads in the project area, there would be no connected actions including opening maintenance, tag alder regeneration, scarification for natural conifer regeneration, no watershed restoration work, and no fisheries stream habitat improvement work. There would be 4 miles of road maintenance (FR 6950). It is possible that potential habitat exists in the Cisco Branch of the Ontonagon River, the South Branch of the Ontonagon River, Sucker Creek, Redlight Creek and Choate Creek.

There are no proposed harvesting actions in this alternative in the Wild and Scenic River corridors for the Cisco Branch or the South Branch of the Ontonagon River, thus no increases in the level of risk, no increase in water temperature due to canopy removal, no expected hydrological changes in the streams due to human manipulation (i.e. additions fo structures or woody debris). Other conditions,like fish host populations, changes in dissolved oxygen, or nutrients are not expected to change in this alternatives.


The four miles of road maintenance (FR 6950) in this alternative will not have any effects on stream water quality because this road does not cross any permanent stream or river in the project area. This road will not contribute sediment to any permanent stream in the project area. There are some road crossing that will go unattended in this alternative and some of these crossings are contributing sediment to stream and rivers. Tthe most noteable is the FR 6987 crossing of Redlight creek. Sediment is entering the stream at this crossing and represents a negative impact to mollusks downstream of the culvert. The sediments may bury riffle habitat where the mollusks feed, or a large addition of sediment may actually bury the mollusks faster than they can move and end up killing them. Sedimentation in the stream can affect mollusks indirectly by changing habitat conditions for the host fish species in the stream, and without the hosts mollusks cannot successfully reproduce. There is also one small (currently an ATV crossing) on Choate creek. FR6975-E7 crosses Choate creek and the crossing is by ATVs. There is some potential for sediment to enter the stream at this crossing. The other road crossings are crossings at intermittant streams and drainages. Any sediment moving into these intermittant drainages will not have a direct impact on potential mollusk habitat in the permanent streams, the effect will be indirect as some of the sediment maybe trapped in the intermittant drainages, but some sediments may make its way to the perennial streams over a long period of time.

Cumulative effects


Cumulative effects were assessed at the project area scale. In the last fifteen years (1987-2002) approximately 214 acres of aspen has been harvested in the project area. These harvest were all clear cuts and this amounts to only 2 1/2% of the project area in 15 years. This is a minor amount of area and the harvests revegetate in a short period of time, about three years. The cumulative effects past harvest actions are thought to be indirect and minimal.



The maintenance of FR 6950 would not produce any cumulative effects because the road does not cross any streams. The greatest input of sediment into streams that has the potential to enter the streams are the undersized culverts associated with Redlight creek. There are other culvert needs associated with the exisitng transportation system that will not be addressed in alternative 1. These will continue to cause some cumulative effects to potential mollusk habitat in the project area.
Alternative 2 (Modified Proposed Action)

The modified clear cuts on 1,027 acres would remove the mature aspen, which would remove the canopy to stimulate growth aspen suckers and regenerate a new stand. A stand of new trees rapidly occupies the site in 1 to 3 year, and there is growth of herbaceous material rapidly covers the exposed soil surfaces. None of the proposed aspen harvests are located with the Wild and Scenic River corridors for the Cisco Branch or the South Branch of the Ontonagon River. None of the modified clear cuts extend to the edge of Choate, Relight or Sucker creeks. There will be untreated stands of trees between the edge of the modified clear cuts and the stream bank, the actual distances described in design criteria in Chapter 3 of the EA. There are also riparian design criteria to mitigate the effects of the modified clear cuts the intermittent drainages adjacent to or within some of the modified clear -cut units. Most of the modified aspen clear cuts will be harvested either during the winter or during the dry summer months of mid-July to September, which would limit the exposure of the harvest units to surface disturbance and reduce the amount of exposed bare soil to erosive processes. The rapid re-vegetation, season of operation, layout of the harvest units and use of BMPs and riparian design criteria will limit amount of bare surface exposed to erosional processes and mitigate any potential sedimentation risks. The modified aspen clear cuts will not produce any direct effects that would negatively alter stream water quality or increase stream sedimentation in any potential mollusk habitat in the project area.

Under Alternative 2, about 256 acres would receive management treatment. Individual tree selection harvest in northern hardwood stands would not affect potential mollusk habitat because these treatments will retain an overstory canopy and are not located adjacent to any permanent stream, and riparian design criteria and BMPs will be applied as necessary. Treatmentof these stands would not have any direct or indirect effects on potential mollusk habitat in the project area.




1   ...   8   9   10   11   12   13   14   15   ...   19


The database is protected by copyright ©hestories.info 2017
send message

    Main page