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Barry R. Taylor
Associate Professor Department of Biology, St. Francis Xavier University Room 315, J Bruce Brown Hall
E-mail: btaylor@stfx.ca Telephone: 1-902-867-3873 Laboratory Telephone: 1-902-867-3748 |
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Shanel Raney, from New Glasgow, Nova Scotia, completed her Honours project looking at the effects of disturbance on open bogs in south-western Nova Scotia. Her work showed that bog vegetation responds to even small alterations of drainage, and that traffic from all-terrain vehicles creates a disturbance that changes the frequencies of various plant species. She also explored subtle effects of all-terrain vehicles on thread-leaved sundew (Drosera filiformis), an extremely rare bog plant. |
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Jantina Toxopeus, from Edmonton, Alberta, spent a summer trying to fathom the exceptionally fast litter decomposition in downstream reaches of Barneys River, Pictou County. Maple and alder leaf litter in this river disappear completely in under four weeks, whereas most streams produce 50% mass loss in six to seven weeks. Field evidence suggests that poor litter retention leads to severe resource limitation among bottom-dwelling insects, which rapidly exploit any leaves that remain in the river. Jantina's work explored the spatial extent of the rapid-decay zone, and attempted to relate decay rates to populations of leaf-feeding invertebrates and water temperature. |
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Meghan Hines, from Chezzetcook, Nova Scotia, spent two summers trying to figure out why mixtures of leaf litter from two species decompose more rapidly than leaves of only one species --except when they don't. We looked at the effect of water temperature and nutrient supply on decay rates and colonization by fungal and invertebrate decomposers in a range of local streams and rivers. This vexing question has implications for models of litter decomposition and energy flow in streams, as well as diversity theory. |
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Irene Andrushchenko (on the right, with Meghan Hines) from St. John, New Brunswick, completed her Honours project comparing upstream-downstream differences in litter decomposition in three local river systems (Pomquet, Sutherlands and Barneys). The absence of leaf-shredding invertebrates slows decomposition in rivers even when the water is warmer than upstream. She tested this idea on three boreal rivers in Norway as part of her M.Sc. project. |
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Trevor Floyd, from Antigonish, Nova Scotia, completed his M.Sc. studying the effects of river restoration on spawning success of Atlantic salmon, in cooperation with Department of Fisheries and Oceans. Restoration of Brierly Brook used "digger logs" that emulate fallen trees and bank deflectors that narrow the channel and encourage meanders. Numbers of spawning salmon jumped by an order of magnitude following restoration, and densities of parr increased proportionately. The work also revealed a complex control of spawning success by beaver dams and autumn rainfall. |
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My principal research interest is the ecology of streams and small rivers in northern Nova Scotia. Within that field I have been following three lines of research: decomposition and transport of leaf litter; restoration of habitat for Atlantic salmon; and ecology of rare floodplain plants.
Decomposition and transport of leaf litter
Detrital carbon (plant litter) is at once the main structural material and the energy currency supporting aquatic ecosystems. The quantity and quality of plant litter that a river receives determines the nature and productivity of the entire ecosystem, from bacterial and fungal decomposers to benthic invertebrates and fish. Detrital carbon also creates a strong connection between streams and the terrestrial ecosystems through which they flow.
My research examines rivers in the Antigonish area, including the South, West, Rights, Pomquet, Barneys and Sutherlands rivers. All these rivers are about the same size and run in parallel drainages into the sea. They provide a neat set of natural replicates in which to compare detrital carbon dynamics. Work to date reveals that the dynamics of litter decomposition are very different between streams and rivers and between summer and autumn. Microbial growth is fostered by warmer temperatures, but leaf-feeding insects are largely confined to cool streams, creating a complex response of decomposition rate to temperature.
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Right: Effect of water temperature on decomposition of alder (Alnus incana) leaves in Nova Scotia rivers. The rate declines above 14oC, the upper lethal temperature for the leaf-shredding stonefly, Leuctra, which is confined to cool, woodland streams.
Current and future work is aimed at learning how organic matter is retained and transported in small streams compared with rivers. Retention in Nova Scotia rivers appears to be very poor, suggesting that much material is exported to the estuaries before it can provide energy to the river ecosystem. |
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Restoration of habitat for Atlantic salmon
Populations of Atlantic salmon are in decline worldwide. Part of the cause of the decline may be loss of suitable spawning habitat in freshwater streams because of human alterations of the channel and the basin. Continuing efforts to restore Brierly Brook, James River and other waterways in the Antigonish area suggest that spawning success of Atlantic salmon may be dramatically improved by restoration. The restoration method uses strategically placed logs and rocks to recreate the complexity of the stream channel and encourage the stream to return to its natural structure of pools and riffles.
(Photo by Trevor Floyd)
Acknowledgement: The Rivers Research Laboratory is funded by Department of Fisheries and Oceans, St. Francis Xavier University, and when necessary, bake sales.
Ecology of rare floodplain plants
As a sidelight to my work on the St. FX Herbarium, I have been studying the ecology of Triosteum aurantiacum (Wild Coffee, Tinker's Coffee-weed) in river flood plains. This provincially rare plant is widely distributed along the lower South, West and Pomquet rivers, but is strictly limited to rich flood plains. The flood plain forests of the region are hot-spots of plant diversity, and harbour a number of infrequent or rare species which cannot survive in the base-poor, disturbed soils of the uplands.
Triosteum aurantiacum
Canada Lily (Lilium canadense) another rare plant restricted to floodplains in northern Nova Scotia
I act as Curator of the St. Francis Xavier University Herbarium (Acronym:
STFX), and take responsibility for maintaining and expanding the
vascular plant section of the collection. (Dr. David
Garbary maintains the other half of the collection, devoted to
seaweeds and other algae.) Our vascular plant collection consists
of about 4500 sheets, almost all representing species from northern Nova
Scotia. The collection is actively expanding. The photograph
on the right shows new specimens waiting to be labelled and catalogued.
I am especially interested in finding new occurrences for rare plants and establishing a better record of the flora of the tri-county area of northern mainland Nova Scotia (see the GAP Project, below). This is an area where students or serious amateurs can make a real contribution to science and to the University. We encourage anyone who is interested in field botany to lend a hand.
The GAP Project
The flora of northern Nova Scotia is poorly known relative to that in other parts of the province. Unstructured collecting to augment the STFX herbarium over the past few years has produced dozens of new records of plants that are either provincially rare or previously unknown from this region. I have begun a long-term project to at once augment the vascular plant collection at STFX and fill in missing information concerning plant distributions in northern Nova Scotia. The project concentrates on Guysborough, Antigonish and Pictou counties, so it seemed appropriate to call it the GAP Project.
Over the course of this open-ended project, the collecting effort will concentrate on specific habitats and locations where the probability of discovering overlooked species is greatest or where our present knowledge is least complete. I hope to make repeated visits to the same or similar habitats over the course of the season, to follow the phenology of flowering plants and capture species that might be overlooked in a single visit. The first priorities for the GAP Project are river flood plains and dolomite outcroppings.
The GAP Project is based entirely on volunteer work. If you
wander in the woods regularly and have a keen eye and some interest in
botany, we would welcome your help.