The Southern Limestone/Dolomite Valleys and Low Rolling Hills level IV ecoregion is karst topography – a landscape dominated by limestone and dolostone. Because most of the ecoregion is valley, the karst provides numerous springs and sinkholes. Caverns are found beneath the valley floor, but passable entrances into them are rare.
The pre-settlement landscape of this ecoregion’s valleys supported moist forests with many types of trees. Due to the moist nature of the valley’s ecosystems, wildfires were rare and could occur only during severe droughts. The bedrock beneath the floor of these valleys weathers into alkaline soils that supported agriculture when the region was first settled.
There are a few low hills that rise from the valley floors of this ecoregion. Most are composed of harder rocks, especially chert and sandstone, which resist erosion more than the limestone and dolostone. In pre-settlement times, the hills provided habitat for plants and animals suited for dryer ecosystems. Wildfires started by lightning would burn these hills periodically, probably about once every decade, but no one knows for sure.
This level IV ecoregion is nested within the Ridge and Valley level III ecoregion, an area dominated by linear ridges and intervening valleys. The diverse topography and geology of this region supports many ecosystems, and thus, many species.
-R. Scot Duncan