Transcript The Plants of our Limestone Barrens

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
October 12-13, 2006
Plants? … What plants? …
Cape Norman
At first glance, there’s almost nothing there!
Burnt Cape [photo: Pat Montegue]
But, when you begin to look more closely …
Watt’s Point
… usually MUCH more closely….
Watt’s Point
Flowers Cove
You’ll see an amazing garden of
botanical treasures!
Redtipped Lousewort - Pedicularis flammea – Big Brook
Some quite spectacular …
Glacier Sedge – Carex glacialis – Boat Harbour
Others pretty dull …
But, what’s all the fuss
about?
Alpine Ragwort - Packera pauciflora – L’Anse aux Meadows
Dwarf Hawk’s Beard – Crepis nana – Burnt Cape
What makes these plants so special?
Aren’t they just like plants from other places?
Common Dandelion – Taraxacum officinale – Raleigh
Well … some are …
Northern Anemone - Anemone parviflora – Burnt Cape
But most aren’t …It’s all a bit complicated
Our limestone barrens species fall into
about 5 special categories …
… grouped by their general distribution
near Eddies Cove West
1. Newfoundland Endemic “Limestone-Loving” Species
Species found only in Newfoundland, in the whole world!
Barrens Willow – Salix jejuna – Cape Norman
Fernald’s Braya – Braya fernaldii – Big Brook and Watt’s Point
Long’s Braya – Braya longii
Sandy Cove and Yankee Point
… and, MAYBE?
“Burnt Cape Cinquefoil” Potentilla usticapensis … [or
Potentilla pulchella var.
pulchella]
… There are varying
taxonomic interpretations
… so its endemic status is
uncertain
Burnt Cape
2. Gulf of St. Lawrence Endemic “Limestone-Loving” Species
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!
St. Lawrence Primrose – Primula laurentiana – Raleigh
Newfoundland Pussytoes –
Antennaria eucosma
Cape St. George
Longleaf Arnica – Arnica lonchophylla – Humber Gorge
3. Disjunct “Limestone-Loving” Species
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
Newfoundland Orchid –
Pseudorchis albida subsp.
straminea
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
4. More Widespread “Limestone-Loving” Species
Calypso Orchid - Calypso bulbosa var. americana – Burnt Cape
Yellow Ladyslipper – Cypripedium parviflorum var. pubescens – Port au Choix
Small Roundleaf Orchis - Amerorchis rotundifolia – Burnt Cape
Frog Orchid – Dactylorhiza viridis
Killdevil Mountain [photo: M.
Anions] and Burnt Cape
Purple Mountain Saxifrage – Saxifraga oppositifolia – Table Mountain
Tufted Saxifrage - Saxifraga cespitosa – Old Port au Choix
Island Gentian – Gentianopsis nesophila – St. John Bay
Alpine Chickweed – Cerastium alpinum subsp. lanatum – Lower Cove
White Mountain Avens – Dryas integrifolia
Sandy Cove [photo: N.
Djan-Chekar] and Flowers
Cove [photo: Pat
Montague]
Yellow Mountain Saxifrage – Saxifraga aizoides – Eddies Cove West
Alpine Bearberry - Arctous alpina – L’Anse-au-Loup
Newfoundland Oxytrope – Oxytropis campestris var. minor – Mount Parent, P.Q.
Elegant Milkvetch - Astragalus eucosmus – L’Anse aux Meadows
Hairy Willow - Salix vestita – Port au Choix
5.
Widespread Species which are not “Limestone Loving”
They’ll grow almost anywhere!
Larch – Larix laricina – Big Brook
White Spruce – Picea glauca – Table Head [photo: Pat Montague]
Living on the limestone barrens can be quite a challenge!
How do the plants manage it?
Trailing Juniper - Juniperus horizontalis – Port au Choix [photo: Pat Montague]
What conditions do they have to overcome?
Alpine Pussytoes – Antennaria alpina subsp. canescens – Watt’s Point
Many, it seems!
It is really useful to understand what makes
barrens of ANY type, “barrens”.
Cape Norman
The first challenge is DRYNESS … even in areas that receive a
lot of moisture
Burnt Cape [photo: Pat Montague]
Wind is usually the critical factor
… especially in winter.
It’s not hard to tell how deep the sheltering snow gets in this area!
Eddies Cove
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
Dwarf Hawk’s Beard – Crepis nana – Burnt Cape
Tight cushion architecture can conserve a core of dampness
within the cushion
Flowers Cove,
“White Rocks”
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
Rand’s Eyebright - Euphrasia randii – Cape St. Francis
Hair creates a layer of dead air against the plant
surface to help slow moisture loss when the plant’s
pores are open
Netvein Willow – Salix reticulata – Lower Cove
Waxy and leathery surfaces help slow water loss from the surface
Reddish Sandwort - Minuartia rubella – Port Saunders
Narrow leaves with less leaf surface area lose less water
The second challenge of the barrens is COLD.
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
W of Red Bay, Labrador, July 12, 2001
The main thing affected by cold is the total
length of the growing season …
L’Anse-Amour, Labrador
This photo was taken July 8 – and the willows are still
just in early bud!
Moss Campion – Silene acaulis – Burnt Cape
Tight cushion architecture allows for a layer of “dead air”,
within the cushion, that can warm up and stay warm all day
Cold also leads to frost disturbance ….
Watt’s Point
… seen most dramatically in patterned ground
Burnt Cape [photo: Pat
Montague
Daubenmire (1941)
tap roots anchor plants
deeply into the seasonallydisturbed frost-heaved
soils
This rare species, the Cutleaf Fleabane, grows in
Humber Gorge
Long’s Braya – Braya longii – Yankee Point
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.
Boat Harbour
The THINNESS of the soil is largely the result of ice-age glacial
scouring …
Glacial Striae – Hawkes Bay
Cape Norman
… and subsequent wind and water erosion.
Cape Norman
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.
Cape Norman
But even here, plants manage to grow …
Barrens Willow - Salix jejuna - Cape Norman
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!
Arctic Bladderpod - Lesquerella arctica – Burnt Cape
As you have already seen, plants of the barrens
have all kinds of survival tricks
Moss Campion – Silene acaulis
Daubenmire (1941)
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
In the limestone barrens, the chemistry of calcium
adds to the challenge
Encrusted Saxifrage - Saxifraga paniculata – Burnt Cape
This saxifrage secretes excess lime from the edges of its leaves
A major advantage of living on the barrens – is a lack
of competition!
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
Yankee Point
But, in general, the plants of the barrens live on a razor’s edge
Burnt Cape
Alpine Milkvetch – Astragalus alpinus var. alpinus – Burnt Cape
… with the rarer ones just making it …
Balsam Ragwort – Packera paupercula var. balsamitae – Indian River
… and some others doing much better
… But, we really don’t know what’s ahead for them
Peter Scott
… will climate change help
Long’s Braya … but hinder
Fernald’s Braya?
… or vice-versa?
… or neither!
We might guess … but
we really don’t know.
Will humans and nature eventually find ways happily
co-exist?
It would be nice!
One thing is for sure … Even as tourists arrive in increasing
numbers …
Cape Norman
… and humans in general continue to expand their influence
Heavy equipment re-arranging the Romaines River floodplain, August 1, 2006 !
We still have much to learn
Boat Harbour
… any many discoveries
to make!
… End
Crab Spider on Yellow Lady Slipper – Burnt Cape