Lesson 9: Biodiversity and Plant Adaptations

What does biodiversity look like in mountains?

Mountains provide some of the world’s most spectacular landscapes and host an amazing diversity of species and habitat types.

Within just a few hundred meters of elevation on a mountain slope, you can travel through ecosystems and plant communities that are otherwise separated by many hundreds of kilometers of latitude between the equator and the poles.

What is biodiversity? what is it related to?

The number of species in a certain area

Think of distribution, variation and role too!!

What are some of the challenges of mountain environments?

Cold

Intense solar radiation

Less partial pressure

Therefore plants and animals must be well adapted

Who is Alexander Von Humboldt? what did he contribute to biodiversity?

A Prussian geographer and naturalist

His 1807 Essay on the Geography of Plants was based on the then novel idea of studying the distribution of species along gradients of varying physical conditions.

These patterns were famously depicted in his cross-section sketch of Chimborazo, a massive, 6310 m stratovolcano and the highest mountain in Ecuador.

What is speciation?

Occurs when populations diverge genetically from one another and can no longer interbreed

They must be genetically isolated; no movement from one place to another.

What is allopatric speciation? an example?

Common in mountains with topographic barriers to limit dispersal = Physical isolation

A main contributor to speciation in the mountains

EG Pyruvian Metaltail, Bellflowers

What is refugia?

Places in mountains with favourable conditions in times of extreme changes

What are the three measures of biodiversity?

Species richness: how many species are in an area

Species evenness: how similar species are in their relative abundance

Species diversity = richness + evenness; provides info on how ecosystems function in mountain environments

What is DNA barcoding? what is it used for?

Used to assess populations

DNA Barcode: small segment of DNA in all living organisms

Sequenced to identify different species

Helps us to quickly identify species

Important in hyperdiverse groups

Helps us to ask new questions

Can do this across many species at the same time; especially small organisms

What are endemic species?

species only found in one area of the world

What is an example of a mountainous endemic species?

The Banff Springs Snail; Found in Cave and Basin National Historic Site, Banff National Park

First identified in 1936 in Sulphur Mountain, Banff National Park, Canada.

Adapted to life in thermal springs; high in temperature (+20 C) and sulphur dioxide.

They eat bacteria (sulphur), algae and dead plant matter.

They experience seasonal population fluctuation.

→ Threatened by frequent drought , and drying of springs

Listed as Endangered in Canada’s National Species at risk act

How many hotspots of biodiversity are there? an example?

>35 biodiversity hotspots worldwide

hotspots represent just over 2% of the Earth’s land area, they’re home to about half of the world’s endemic species.

Protecting and managing hotspots is important

EG Andes: Natural alpine habitat

What are some explainations for biodiversity hot spots?

Past climate Shifts

Tectonic Events

Modern Ecological Interactions

Limited Dispersal

What are two hypotheses for patterns of biodiversity? what is the reality?

1. Geographical area hypothesis = larger areas can support more species. Decreasing species diversity at higher latitudes and elevations may just be a consequence of inherently smaller areas of habitat availability.

2. Productivity hypothesis proposes = higher primary productivity, associated with higher temperatures in the tropics and at lower elevations, contributes to higher biodiversity.

In reality there is no single explanation for patterns of species diversity in mountains, and there are a number of contributing factors that vary from place to place.

What are Nunataks? why are they important?

tops for mountains sitting outside ice sheets where some endemic species remain

These nunataks will eventually become connected and species will move along, creating new evolutionary trends

Isolation is a key driver

Mountains are refugia!!

Why is biodiversity important?

Beauty of nature; variety of unique charismatic species

Critical to ecosystem functioning: insurance buffering against loss in environmental change as different species, have different tolerance

Diversity of vegetation is critical to slope stability; avalanches and landslides which degrade water supplies

What is the Diversity-Stability Hypothesis?

In highly diverse ecosystems there are species that can help replace species that are disrupted in environmental change

When were ecosystem services defined?

the 2005 millennium ecosystem assessment

What are biological adaptations?

traits that enhance a species survival in certain conditions

What are some adaptations of conifers to alpine environments?

Evergreens; photosynthesize longer until the fall and start earlier in the spring. Have needles and cones

Needles allow conifers to thrive; compact, small SA, waxy coating (cuticle), extensive root systems. All help retain moisture.

Shape of conifers helps them shed snow

Woody tissue contains vessels resistant to freezing breakage (narrow tracheids)

What are the adaptations of White Bark Pine and Limber Pine?

• Crumholds growth form

• Grow at very high elevations

• Do not reach full cone production until 60-100 years old

• Fire plays an integral role to produce open areas for seed dispersalist such as clarks’ nutcrackers

What are some features of whitebark pine?

Whitebark Pine (5 needles, pollen and seed cones) = Keystone species; Regulates snowmelt for other species

Seedlings need open stands; fire dispersal

Whitebark pine cones needs the nutcracker to open the cone

Species at risk in Alberta

What are the main threats to white pine? how do parks in waterton manage this?

Change in fire regime ; letting fires burn

Climate change

White pine blister rust

→ Protect mature seeds producing cones (40-60 seeds / cones)

Find trees with better resistance to disease and grow these seeds up and replant them (1000 trees / site)

What is a main adaptation of Larch and Tamaracks?

Shed their needles in the fall

Softer needles are less hardy and costly to produce

Also produce cones earlier in the season. They efficiently extract nutrients from needles in the fall. = golden larch season in the fall

What are the two main pathways for adapatations of alpine plants?

1. Increase radiative heat gain

Dark colouring

Orient towards the sun

Compact growth form – up to 15 C warmer

2. Decrease convective cooling

Grow in microclimates

Dense hairy surface (pubescence) to trap air increasing boundary layer

Compact growth form (cushion growth form)

What is the subnivean layer?

Snow provides a protective layer; from temperature, wind and graduation

What is the cushion growth form? its benefits?

Cushions are tightly packed clusters of many smaller stems. The cushion growth form is a highly effective way to stay warm, as it both increases radiative heat gains and restricts air movement through the low canopy.

Temperatures in a cushion can be up to 15°C warmer than the surrounding air temperature.

Cushion plants can act as a microclimate = Ecosystem engineers

What is a rosette growth form? its benefits?

The rosette growth form is also common in alpine environments, with individuals having a circular, basal arrangement of leaves.

The erect, flowering stems of the rosette growth form are more exposed, but this is also an adaptation for seed dispersal and attracting pollinators.

What are the 3 main plant physiological adaptations to freezing tolerance?

1. Freezing point depression: increase solutes to lower freezing point

2. Supercooling: segregating water into cells where they cannot combine with other water to make ice

3. Dehydration by ice segregation: segregate water into outside of cells so they cannot cause damage

What is transpiration and evaporation?

Plants lose water through a process called transpiration. Transpiration involves both water transport within a plant and the loss of water from the plant to the atmosphere, through evaporation

Where does carbon dioxide diffuse into leaves as water diffuses out?

Stomatas

How does transpiration change at higher elevations?

increases at high elevation, making it challenging for plants to retain moisture. Hairy, fuzzy and succulent leaves can reduce transpiration rates which help plants cope with dry and windy conditions.

How do alpine plants store water and nutrients?

Roots:

Tap root systems: one single main root; Helps to stabilize plant as an anchor and to reach deeper water and soil

High roots to shoot ratio

EG Pasqueflowers, Gentians and Oxytropes

What are lichens? how are they well adapted?

Symbiosis of algae and a fungus

• Dormancy in dry conditions

• Fungal layers can take up more water than their weight

T/F Alpine plants are mostly perrenials? why or why not?

True

Perennials are plants that persist for >2 years are better adapted to alpine conditions than annuals

Perennials can persist through tough years and produce when more stable

T/F Plants can undergo asexual reproduction? why or why not?

True

As sexual reproduction is challenging with low pollinator diversity and low seed viability

What form of asexual reproduction do plants undergo? an example?

Vegetative reproduction: a process by which new plants grow from parts of parent plants

EG From Rhizomes: modified underground stems

→ Persist in conditions unfavourable to sexual reproduction

What are some traits to attract pollinators?

Large, scented flowers

Higher proportion of flowers

Bloom early in the season

Flower shape and colour to specific pollenators

What are some common traits of alpine flowers?

Darker flowers to trap heat

Cup shaped flowers to trap heat

Heliotropic: follow the sun (+7C) EG Mountain Avens and Snow butterfly (increased germination up to 40%)

Are flies or bees generalists?

Flies = better pollinators