Presentation on theme: "Plants of the Limestone Barrens A Presentation by John Maunder Curator Emeritus of Natural History The Rooms Provincial Museum of Newfoundland and Labrador."— Presentation transcript:
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
Fernald’s Braya – Braya fernaldii – Big Brook and Watt’s Point
Long’s Braya – Braya longii Sandy Cove and Yankee Point
Burnt Cape “Burnt Cape Cinquefoil” - Potentilla usticapensis … [or Potentilla pulchella var. pulchella] … There are varying taxonomic interpretations … so its endemic status is uncertain … and, MAYBE?
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
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. Eddies Cove It’s not hard to tell how deep the sheltering snow gets in this area!
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 Trailing Juniper – Juniperus horizontalis – Port au Choix [photo: Pat Montegue]
Tight cushion architecture can conserve a core of dampness within the cushion Dwarf Hawk’s Beard – Crepis nana – Burnt Cape
Some plants find other ways to stay out of the wind Flowers Cove, “White Rocks”
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 …
This photo was taken July 8 – and the willows are still just in early bud! L’Anse-Amour, Labrador
Tight cushion architecture allows for a layer of “dead air”, within the cushion, that can warm up and stay warm all day Moss Campion – Silene acaulis – Burnt Cape
Cold also leads to frost disturbance …. Watt’s Point
… seen most dramatically in patterned ground 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 Daubenmire (1941)
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. Long’s Braya – Braya longii – Yankee Point
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
… 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 … 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
Even so, some species, like this buttercup, seem to need such changing conditions! Oval-leaf Spearwort – Ranunculus flammula var. ovalis – Port au Choix
As you have already seen, plants of the barrens have all kinds of survival tricks Arctic Bladderpod - Lesquerella arctica – Burnt Cape
LONG ROOT SYSTEMS are critical in accessing scarce moisture and nutrients from a very wide area of soil Moss Campion – Silene acaulis Daubenmire (1941)
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 This saxifrage secretes excess lime from the edges of its leaves Encrusted Saxifrage - Saxifraga paniculata – Burnt Cape
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
… with the rarer ones just making it … Alpine Milkvetch – Astragalus alpinus var. alpinus – Burnt Cape
… and some others doing much better Balsam Ragwort – Packera paupercula var. balsamitae – Indian River
… But, we really don’t know what’s ahead for them Peter Scott
We might guess … but we really don’t know. … will climate change help Long’s Braya … but hinder Fernald’s Braya? … or vice-versa? … or neither!
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 !