Plants of the Limestone Barrens. A Presentation by John Maunder Curator Emeritus of Natural History The Rooms Provincial Museum of Newfoundland and Labrador The Limestone Barrens Habitat Stewardship Program Conservation and Sustainable Ecotourism Conference Plum Point, Newfoundland
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A Presentation by John Maunder
Curator Emeritus of Natural History
Provincial Museum of Newfoundland and Labrador
The Limestone Barrens Habitat Stewardship Program
Conservation and Sustainable Ecotourism Conference
Plum Point, Newfoundland
October 12-13, 2006
Burnt Cape [photo: Pat Montegue]
You’ll see an amazing garden of botanical treasures!
Some quite spectacular …
Others pretty dull …
Alpine Ragwort - Packera pauciflora – L’Anse aux Meadows
Well … some are …
But most aren’t …It’s all a bit complicated
… grouped by their general distribution
near Eddies Cove West
Species found only in Newfoundland, in the whole world!
Fernald’s Braya – Braya fernaldii – Big Brook and Watt’s Point
Sandy Cove and Yankee Point
“Burnt Cape Cinquefoil” -Potentilla usticapensis … [orPotentilla pulchella var. pulchella]
… There are varying taxonomic interpretations
… so its endemic status is uncertain
Species found only in the Gulf of St. Lawrence region (which includes the Newfoundland west coast and Strait of Belle Isle), in the whole world!
Cape St. George
Species found both in some far-away place, AND in our area, with a BIG GAP in between.
Dwarf Hawk’s Beard – Crepis nana – Burnt Cape …. Disjunct to N tip of Labrador, and arctic and western North America
Burnt Cape - Disjunct to Greenland and one locality in Hudson Bay
Woolly Arnica – Arnica angustifolia subsp. tomentosa – Point Riche Peninsula … Disjunct to mountains of northwestern North America [photo: Rene Charest]
Pendantpod Oxytrope - Oxytropis deflexa var. foliosa – disjunct [from S Labrador] to N tip of Labrador, Gaspe, Hudson Bay, and low arctic and western North America
Bodin’s Milkvetch – Astragalus bodinii – Cook’s Harbour … disjunct to western North America
Yellow Ladyslipper – Cypripedium parviflorum var. pubescens – Port au Choix
Killdevil Mountain [photo: M. Anions] and Burnt Cape
Purple Mountain Saxifrage – Saxifraga oppositifolia – Table Mountain
Sandy Cove [photo: N. Djan-Chekar] and Flowers Cove [photo: Pat Montague]
Newfoundland Oxytrope – Oxytropis campestris var. minor – Mount Parent, P.Q.
They’ll grow almost anywhere!
Trailing Juniper - Juniperus horizontalis – Port au Choix [photo: Pat Montague]
Alpine Pussytoes – Antennaria alpina subsp. canescens – Watt’s Point
It is really useful to understand what makes barrens of ANY type, “barrens”.
The first challenge is DRYNESS … even in areas that receive a lot of moisture
Burnt Cape [photo: Pat Montague]
It’s not hard to tell how deep the sheltering snow gets in this area!
Trailing Juniper – Juniperus horizontalis – Port au Choix [photo: Pat Montegue]
Even in summer, it helps to have a low profile to stay out of the drying wind, and within the thin, sun-warmed, surface air layer
Tight cushion architecture can conserve a core of dampness within the cushion
Some plants find other ways to stay out of the wind
Laurentian Fragile Fern – Cystopteris laurentiana – Flowers Cove “White Rocks”
Other plants just grow smaller in exposed areas [while usually preserving flower size!]
Greenland Primrose – Primula egaliksensis – Cook’s Harbour and Boat Harbour
Hair creates a layer of dead air against the plant surface to help slow moisture loss when the plant’s pores are open
Waxy and leathery surfaces help slow water loss from the surface
Narrow leaves with less leaf surface area lose less water
However, cold is only partly a winter concern. For most arctic and alpine plants, once the temperature has dropped below a certain point, cold is just cold
The main thing affected by cold is the total length of the growing season …
This photo was taken July 8 – and the willows are still just in early bud!
Burnt Cape [photo: Pat Montague
tap roots anchor plants deeply into the seasonally-disturbed frost-heaved soils
This rare species, the Cutleaf Fleabane, grows in Humber Gorge
Some roots are contractile ... each time a plant is heaved upward by frost, the root of the affected plant shortens to pull the plant back down into the soil, where it belongs.
The third challenge of the barrens is obtaining sufficient NUTRIENTS. Barrens usually occur on thin, poor soils.
The THINNESS of the soil is largely the result of ice-age glacial scouring …
Glacial Striae – Hawkes Bay
… and subsequent wind and water erosion.
The POORNESS of the soil is usually the result of its basic geology, or of its history of poor organic accumulation in places where vegetation has long been sparse.
But even here, plants manage to grow …
In general, precipitation tends to run off quickly … or just drain away, downwards, through the substrate …
carrying unconsolidated nutrients with it.
Port au Choix
Oval-leaf Spearwort – Ranunculus flammula var. ovalis – Port au Choix
Even so, some species, like this buttercup, seem to need such changing conditions!
As you have already seen, plants of the barrens have all kinds of survival tricks
LONG ROOT SYSTEMS are critical in accessing scarce moisture and nutrients from a very wide area of soil
EVERGREEN LEAVES conserve hard-won and costly resources that would otherwise be lost, and have to be regenerated every year …
Hollyfern - Polystichum lonchitis – Burnt Cape
….and, as long as evergreen plants stays relatively green throughout the year, photosynthesis can take place, on warm days, in any season, effectively lengthening the plant’s growing season
Trailing Juniper – Juniperus horizontalis – Port au Choix
Encrusted Saxifrage - Saxifraga paniculata – Burnt Cape
This saxifrage secretes excess lime from the edges of its leaves
Dwarf Hawk’s Beard – Crepis nana – Burnt Cape
Many barrens species, such as Long’s Braya, actually thrive in disturbed areas where nothing else tends to grow
But, in general, the plants of the barrens live on a razor’s edge
… with the rarer ones just making it …
… and some others doing much better
… will climate change help Long’s Braya … but hinder Fernald’s Braya?
… or vice-versa?
… or neither!
We might guess … but we really don’tknow.
It would be nice!
One thing is for sure … Even as tourists arrive in increasing numbers …
Heavy equipment re-arranging the Romaines River floodplain, August 1, 2006 !
Crab Spider on Yellow Lady Slipper – Burnt Cape