CONSERVATION RESEARCH (1992-2012)
a) FLOODPLAINS: RARE WOODLAND HERBS (2011)
Rich deciduous forest floodplains rare herb hotspots (pdfherbs)
This research shows that forest practices must do a better job of managing forest structure and soil nutrients (CALCIUM). Floodplains are a refuge for red-listed southern herbs that can only expand north with climate change if we manage our forests responsibly.
b) LAKESHORES: GLOBALLY RARE COASTAL PLAIN HERBS (1992-2010)
Hill and Keddy (Hill&Keddy) showed how a suite of rare Atlantic Coastal Plain herbs depend on the water level fluctuations that occur on the shores of large watershed area lakes. These plants also depend on low nutrient conditions and this globally significant wetland community is now threatened by pollution origination from mink ranches upstream. The Canadian Botanical Association is considering designating the Tusket River as a national area of special conservation concern.
Hill Keddy and Wisheu (Hydrological Model Dams) showed how the rare plant communities of lakes that were currently dammed could be restored if the hydrological regimes were reinstated. The research also showed that exotic (non-native) plants were a symptom of the disruption of the natural hydrological regime.
Recently, MacKay, Hill and others (2010, Rhodora 112 34-57) showed that disruption of wetlands can fundamentally disturb the genetic base of native species. We showed disturbance induced hybridization between a weedy species and the globally rare, Long’s bulrush and that this genetic pollution of the rare species genepool could be noted in nearby wetlands with no sign of recent human disturbances.
2) Invasive Species (2010, 2011-on-going)
It is often cited with little documentation, that invasive species are the second most important threat to native biodiversity. We have seen above (Hill&Keddypdfherbs) how loss of habitat of large watershed area lakes to damming (and now eutrophication) and floodplain to agriculture and development has resulted in real threats to biodiversity of rare wetland plants. Hill and Blaney (AME Chapter_11.pdf Oct(2)) determine that for over five hundred plants that are exotic in Nova Scotia, there is a handful that have become pests and that could be termed “invasive”.
One of these, the Japanese rose (Rosa rugosa), has invaded an alarming percentage of our beaches and shorelines and is even considered our native rose in a tourism pamphlet from Brier Island. Hill et al. (rosapdf ) in 2010 found the plant in almost half of all beaches visited and in more recent research, found that the plant had taken hold of about 10% of shoreline habitat and that its spread was now aided by ATVs, mink and squirrel.
3) Climate Change Impacts on Maritime Communities (In Press)
The Nova Scotian shoreline is eroding and falling into the sea in many areas. Though this is primarily a result of sea level rise from the natural subsidence of the province’s land mass following postglacial rebound, sea level rise from climate change will be the main driver by mid-century. Sea level change is just one of the impacts of climate change. We are seeing the damaging effects of over-winter warm spells and storm impacts. Research led by the late Sam VanderKloet and soon to be published in Botany, shows how a signature plant of the aromatic coastal heathland of the province, the black crowberry, may be in trouble. Our research considers the plant’s ability to regenerate itself from seed and shows that half of the berries are now maladaptively delivered by animals (mink and gull scats) to the sea edge where seedlings are killed overwinter by storms and erosion. Yet, a portion of the berries are delivered by juncos to nursery areas under the fringe of spruce trees and as this treeline must retreat due to climate change and sea level rise, this shrub land may be able to replace itself. The managers of our province’s biodiversity must develop spatial plans for how native communities can be maintained in the face of climate change and how whole community types (e.g. Appalachian Deciduous Forest) can migrate and adjust their latitudinal positions.