Lecture 11 Grasslands and Rare Plants

Question 1

What is a grassland?

Answer 1

An ecosystem where Poaceae dominates the natural vegetation

Could have a cold season, different dry seasons/wet seasons

Precipitation is not adequate for the development of forests with closed canopies

Natural disturbances are important: fire, grazing animals

Variation in topography at a small scale, and climate at a large scale, gives a great variation in plant communities

Question 2

What are natural disturbances in the NA Prairies?

Answer 2

Bison wallows used continuously over many years, hence providing a high frequency disturbance regime that favours annual plants adapted for colonization of disturbed areas

Fires are less frequent (typically 3-5 years) but spread over wide areas, influencing regional diversity patterns

–> mix of frequencies maximized species diversity

Question 3

What is the diversity of grass growth patterns?

Answer 3

Bunch grasses (not spreading by rhizomes or stolons) VS sod-forming (spreads and makes sods, has rhizomes or stolons)

Cool season grasses (C3 photosynthesis; active growth in spring and/or fall) VS warm season grasses (C4 photosynthesis, active growth in summer)

Question 4

Why does fire favour herbaceous plants over trees and shrubs?

Answer 4

1) Location of growing points
- buds (growing points) of trees and shrubs are located above ground –> growing points not protected

2) Amount of biomass removed by burning
- several years lost in trees/shrubs in terms of productivity

3) Length of time to regain reproductive maturity
- herbaceous plants only losing 1 year of growth (better matched to have frequent fires coming through) –> they can be productive in the same year or the next which is not the case for trees/shrubs

Question 5

What makes growth more difficult towards the Western regions of the Prairies?

Answer 5

Prairie regions’ soil and moisture regimes vary from East to West

In the West, there is less rooting depth and less precipitation
–> Western regions: shortgrass
–> middle: midgrass
–> Eastern regions: tallgrass

Question 6

What are the 4 grassland ecosystems of Canada?

Answer 6

Aspen parkland
Oak savanna
Tallgrass prairie
Shortgrass prairie

Question 7

What is oak savanna? Where is it found?

Answer 7

Grassland with some trees transitional between temperate forest and tall grass prairie

On the Eastern edge of North America grasslands (in Ontario) –> eastern side of the tallgrass prairie

Question 8

What is aspen parkland? Where is it found?

Answer 8

A grassland with open areas, and areas of fairly dense Populus trees

Northern edge: where the boreal forest meets grasslands

Question 9

What are tallgrass prairies? Where are they found?

Answer 9

More precipitation
Plants vigorously growing, no bare soil patches

Found to the East

Question 10

What are shortgrass prairies? Where are they found?

Answer 10

Less precipitation
Plants more water-stressed –> shorter

To the West

Question 11

What are prairie potholes?

Answer 11

Within the different grassland regions, these are shallow wetlands

Very important to waterfowl

Numerous small depressions from altered topography from past, colder landscape that included pingos and from uneven glacial deposits

Not drained by surface flows (i.e. rivers/streams)

Fed mainly by snowmelt, they may dry up (ephemeral)

Past glacial action/melt created the depressions

Question 12

What are some plant adaptations to grasslands?

Answer 12

Deep rooting –> an adaptation to fire

Species have different times of active growth
- benefit is less competition

Question 13

What kind of species in prairie wetlands?

Answer 13

Tall grasses
- same species that are characteristics of Eastern Canadian shorelines/marshes (ex. Phalaris arundinaceae)

Question 14

What is the current state of grasslands in Canada?

Answer 14

Very, very little original prairie is left due to the steel plow –> most grasslands converted for agriculture

Question 15

Why are standardized definitions important in the context of rare species conservation?

Answer 15

Standard definitions are needed to that laws relate to consistent levels of threat for species extinction within each legal jurisdiction

For conservation to be harmonized across the globe for each threatened species as much as is possible

For the application of international laws on the trade and movement of listed rare species

Question 16

What are different assessments of species status from global, national, to provincial?

Answer 16

Global IUCN Red List
COSEWIC: Canada
CDPNQ: Quebec

Question 17

What is the CDPNQ and what is its role?

Answer 17

Centre de donnees sur le patrimoine naturel du Quebec

Keeps track of rare species in Quebec, and updates their status depending on new populations, changes in taxonomy, and new evaluations. They publish their lists on their website

Question 18

What is the threatened/vulnerable and endangered status of CDPNQ?

Answer 18

threatened: species is in a precarious situation, but it is not expected to disappear in the short term

endangered: the species is in decline and is expected to disappear

Question 19

Why are species rare? What do we mean by rare species?

Answer 19

In the context of conservation, we are concerned with declines in the populations of species, such that they are predicted to disappear (become extirpated or extinct) in the near future.

Usually, this is linked to both natural rarity causes, and impacts on the species from direct or indirect human pressures, namely habitat loss and degradation, invasive species, disease, etc.

Question 20

What are the 3 natural causes of rarity?

Answer 20

1) Naturally small population sizes
2) Uncommon habitats
3) Restricted geographic distributions

–> combinations of these three causes give 7 forms of rarity and commonness`

Question 21

What is an example of a rare species due to uncommon habitat?

Answer 21

Species that grow in serpentine soils in the US

(also known as narrow habitat distribution or high habitat specificity)

Question 22

What is an example of a rare species due to restricted geographic distribution?

Answer 22

Golden pothos endemic to a very small and isolate island in French Polynesia

Has since become an invasive species in most countries along the equator due to anthropocentric activity
- also a hardy houseplant

However, most geographically restricted species remain in their ‘home’ region though, giving a much greater chance to become extinct

Question 23

What is an issue with rare species and iNaturalist?

Answer 23

Plant poaching leading to extinctions in the wild of many species

Question 24

What is the main threat to rare species in Quebec?

Answer 24

Habitat loss due to privately or publicly owned land

Protected lands are scarce in the South. Here, the pressure from humans is the highest. Most land is modified, and invasive species/diseases are most common

Question 25

What are the 4 types of distribution patterns in North America?

Answer 25

Peripheral
Disjoint
Sporadic
Endemic

Question 26

What are the main causes of rarity in Quebec?

Answer 26

Northern peripheral distributions (52%)
- distributions which just make it into Quebec at the southern edge of the province account for about half of all rare plants in the province
- Ontario under the pro-development Ford government has recently moved to de-list all species that are common in other jurisdictions
- In other words, rarity in Quebec often encompasses locally rare species (that are more common in other areas of the range). Conservation status of species is often defined at the level of country, not planet. If a species if rare in your country, often it is protected even if it is more common elsewhere.

Narrow habitat preference (42%): plants that grow on high pH or heavy metal rich sites

Question 27

Why is the conservation of isolated populations important?

Answer 27

Conserving the genetic diversity of a species

Question 28

What is a calcareous rock?

Answer 28

A rock that has calcium carbonate (CaCO3) or a variant

Forms from sediments rich in shells and marine fauna

pH is high

Ex. lime and dolomite (sedimentary), marble, veins of calcite in other rocks (metamorphic)

Question 29

What is serpentine?

Answer 29

A name used to refer to rocks that are:
- highly basic
- rich in magnesium silicate and iron
- may be high in other trace metals too

Question 30

What are alvars?

Answer 30

Kind of calcareous habitat where flat rocks (the bed rock) is close to the surface, with a very thin organic layer overtop