Monday, May 25, 2015

Piedmont Savanna Restoration @ Hebron Road

STAR indicates Preserve location,
ARROWS point to surrounding "urban interface"
                                                        The Hebron Road Plant Conservation Preserve, in the Piedmont of North Carolina, is actively managed with the goal of restoring open, savanna-like habitats and a naturally-occurring suite of rare plants. At this site in particular this goal poses many management challenges.  The site is ringed by development including well traveled roads, an elementary school, and a massive subdivision. All these factors make prescribed burning difficult.  
Evening prescribed Burn conducted March 29, 2012
North Carolina has smoke management guidelines that must be followed when conducting prescribed burns.  Our site has a very narrow set of conditions under which it can be burned, meaning only a few days are available each year.  In order to capitalize on one of these infrequent events, in 2012 we burned at dusk, with direct input from the National Weather Service.

4/10/2015 after most recent prescribed fire.
Redbud (Cercis canadensis) and Dogwood (Cornus florida) flowering in background
Brown unburned patches are mostly Indiangrass (Sorghatrum nutans)

The site was burn again in Spring 2015 (regular fires are needed to control woody plant growth, encourage flowering of rare perennials, create seedbeds for germination, etc).  Like many other "growing season" burns, the fire did not consume the undergrowth entirely across the the site.  The most open, grassy areas burned less completely than those where hardwood leaf litter predominated.
Last year's growth of Smooth Coneflower (Echinacea laevigata) stands tall in one of the unburned patches (4/10/15)

4/19/2015 regrowth of Ironweed (Vernonia sp) after prescribed fire. 

The Preserve was established to protect a remnant population of the federally endangered Smooth Coneflower (Echinacea laevigata). When acquired, all the Coneflower stems were found along the roadside.  Slowly, but surely the population continues to expand at the site. Importantly many of the current plants are now found further away from the roadside and the threats that come with it.

 (left): Vigorous patch of Smooth Coneflowers (06/11/14) established from seed collected on-site. Boulders of diabase rock are present.

E. laevigata seedling sprouting after fire (04/07/15)
Narrow-leaf Aster (Symphyotrichum laeve var. concinnum)
seedling sprouting after fire (4/07/15)

Several other rare plants found on the Preserve also appear to benefit from the restoration and management activities. The Narrow-leaf Aster (Symphyotrichum laeve var. concinnum), listed as Threatened in North Carolina and known from only a handful of sites in the Piedmont, is expanding. 

Narrow-leaf Aster (Symphyotrichum laeve var. concinnum)
Fall flowering, Durham Co, NC (10/10/11) 
Erect Bindweed (Calystegia spithamea)
Spring flowering, Durham Co, NC (05/14/15)
Erect Bindweed (Calystegia spithamea), considered a "watch list" species in NC, occurs at the Preserve at what appears to be the easternmost location documented in North Carolina.  This low growing species doesn't appear to compete well as vegetation becomes taller and more robust in the absence of fire. Another rare plant found on the site, Prairie Dock (Silphium terebinthinaceum), also reaches its approximate eastern occurrence in North Carolina here and thrives with fire. I previously discussed this species

Prairie Dock sprouting after spring fire@ Hebron Road Preserve

Prairie Dock flowering @ Hebron Road Plant Conservation Preserve
Fall Flowering (8/23/14)

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