Tampilkan postingan dengan label Delphinium exaltatum. Tampilkan semua postingan
Tampilkan postingan dengan label Delphinium exaltatum. Tampilkan semua postingan

Minggu, 27 Juli 2014

Restoring the Larkspur Savanna



Tall Larkspur (Delphinium exaltatum) approaches its southern range limit in North Carolina. Only a handful of sites have been documented and the species is considered endangered.  Of the 2 documented records in the Piedmont region, one is now extirpated (by the creation of a water line), and the second persists in a narrow slice of habitat between a paved road and a frequently disturbed water line.

Several years ago with the financial support of the NC Natural Heritage Trust Fund (now defunct), we were able to purchase a wooded tract adjoining the lone remaining Piedmont population.  The plan was to restore the densely forested tract hoping the Larkspur could re-occupy more natural habitat away from the constant threats associated with living on the roadside.


Dense patch of Eastern Red Cedar killed by
prescribed fire under large shortleaf pine

Since then, we have conducted 3 or 4 prescribed burns across the tract, combatted invasive species, and cleared some of the dense tree growth present.

The forest has scattered remnant trees with growth forms indicative of savanna growth. However, these were shrouded in dense growth of young Eastern Red Cedar (Juniperus virginiana) and little light reached the forest floor. Prescribed fires and selective tree removal have begun to produce desired results.

After several years, the upland edge of the site has begun to appear much more open.  In the following images a shortleaf pine and dogwood can be seen before and after preliminary restoration; more shortleaf pines become apparent deeper in the woods on the latter image.
   

Maintaining and expanding the developing "Larkspur Savanna" continues to demand resources. 
Restoration in progress at Larkspur Savanna, 2014 (above)
w/small pile of Eastern Red Cedar logs & brush piles
browned ground was dense Japanese Stilt Grass (Microstegium vimineum

Aerial views show the expanding opening.
Site in 2010, before hand-clearing
Site in 2013, after hand-clearing


Over the last several years we have been lucky to have several dedicated individuals carry the load of our restoration efforts at this site.

Earlier this year, Thomas Blaine has taken on thinning and brush-cutting to expand potential habitat. He shocked me, and perhaps himself, with discovery of the first Tall Larkspur plants outside of the original patch!

Not to be outdone, our local Preserve Stewards, Herb & Pat Amyx discovered a few more plants upslope of Thomas' just days later.  Taken together, these finds have expanded the extent of the Piedmont's lone Tall Larkspur population by more than 100 meters.

Minggu, 01 Juni 2014

Diabase Rocks!



Diabase is an igneous rock type found in isolated bands in the Piedmont of North Carolina.  Some of the largest expanses are found in Durham and Granville counties. In these areas, boulders may be common and the soil surface is often interspersed with rocks.  The soils tend to be high in nutrients such as magnesium, have clayey textures, and shrink-swell properties.

(The boulder shown to the right occurs along the edge of a diabase sill in Durham County)


Many unusual and/or North Carolina rare plants may be found on diabase. A few of these are shown below.

Eastern Prairie Blue Wild Indigo (Baptisia australis var. aberrans): Globally rare & listed Endangered in North Carolina. Scientific nomenclature for this plant has varied through time and may continue to evolve. See Weakley's 2012 Flora for a discussion. Image from Durham County, NC
Tall Larkspur (Delphinium exaltatum): Ranked as globally vulnerable by NatureServe and listed Endangered in North Carolina. This image was taken at North Carolina's only remaining Piedmont population; the site in Durham County is now a Plant Conservation Preserve.
Crested Coralroot (Hexalectris spicata): Durham County, NC - wide-ranging & apparently globally secure, but significantly rare in North Carolina.
Hoary Puccoon (Lithospermum canescens); Limited to 2 NC counties and listed as Threatened in North Carolina

Low Wild-Petunia (Ruellia humilis): Widespread in US, but confined to a few Piedmont counties in North Carolina where it is listed Endangered. At least 2 populations are now protected on Plant Conservation Preserves. Image from Granville County
Smooth Coneflower (Echinacea laevigata): Federally and state endangered, extirpated from 2 states in its former range. Smooth Coneflower has been a focal species of conservation efforts in the Durham area since 2004.





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