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Landscape ecology Landscape basics:

pattern: patches, edges, corridors process: disturbance, succession, human impacts

Climate change basics:

Some changes so far Projections for the future Impacts of climate change

Reminder: please do your course evaluations

Final Exam: April 12, 1:30 Gym. Bring ID, pen, calculator.

Landscape ecology 1. Patterns

What kinds of habitat do I have? Where are they? What size and shape are the patches?

Pattern: where’s the forest? Old-Growth forest cover in the contiguous US

1. Big impact of elevation and rainfall: desert, grassland, shrub-steppe, forest. 2. Substantial decline since European colonization. 3. Decline began in east and worked west; remnants in harder-to-reach areas.

Pattern: National Park vs. harvested national forest

Landscape Pattern. . .comes in different sizes

4 m2

16 m2 plots

1 km2

Basic pattern descriptors—two schools of thought

Patch-Corridor-Matrix model: The size, shape, and configuration of landscape patches and corridors define landscape pattern. Landscape continuum model: Landscapes are composed of gradients of vegetative cover.

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Patch-Corridor-Matrix model 1. Draw

boundaries at visual borders

2. Describe size and shape of patches

3. Use spatial statistics to characterize and compare landscapes

Landscape continuum model

Overlay a grid (graph paper!) Describe each square with a continuous number (e.g. tree density) Describe gradients

What’s a patch? (how similar does the interior have to be?)

Defining a Patch Patch = discrete area that is 1) relatively homogeneous, and 2) has a distinguishable boundary

Humans

Environmental

Patch size and configuration matter, a lot, to populations and communities

1. How many individuals of one species supported?

2. How many species can be supported?

3. How many micro-environments occur?

Where do edges come from? Natural responses to physical location

Edges often form in response to elevation, aspect, rain shadows

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Where do edges come from? Natural responses to geology

volcanic, glacial, flood deposits edges around water bodies

Where do edges come from? Responses to disturbance

Any disturbance that occurs in the middle of a patch and changes vegetative structure or composition creates edges. . .

Where do edges come from? Human-induced changes

linear features: roads, power lines, seismic lines, canals, fences, walls

Where do edges come from? Many human-induced changes

rectangular features: zoning, agricultural and forestry boundaries

Basic geometry of edges What features define edges?

Species composition, relative abundance, age structure Structure (closed canopy vs seedlings) Could be abiotic: soil type, moisture, parent rock type Often, it’s a visible change in plant communities. And, often, it is remotely sensed.

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Physical impacts of edges: Wind

Issue: At edges, individuals exposed to higher wind speed relative to within a patch. Consequences: damage, altered moisture. May get changes in seed distribution, pollination.

Physical impacts of edges: light

Issue: At edges, individuals exposed to more light relative to within a patch. Consequences: changed plant community; invasive species often do well on edges. Sunlight also affects heat, so likely get changes in moisture too.

Physical impacts of edges: temperature

Issue: Temperatures vary with moisture, sunlight, and plant density. Individuals at edges will have different temperature regimes relative to areas inside patches. Consequences: Changes in moisture, growth.

Corridor = narrow, linear element that differs from vegetation types on either side.

One more landscape element: corridors

Landscape ecology 2. Process

Disturbance Succession

Disturbance regimes: each ecosystem has characteristic type(s), frequency of disturbance

Mountain pine beetle

Windthrow gaps

Large, infrequent fires

Small, frequent fires

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Fire regimes vary with location Disturbance regimes: many small events, a few big ones Example: Forest fires in BC in 2003

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size of event

Disturbance regimes: variation in time, too Forest fires in BC

2003

1999

2006

Major temporal drivers: --climate (moisture, temperature) --ignition sources (storms, people) --fuel buildup (fire history, beetle, timber)

Extent of land area cultivated globally by the year 2000. Reprinted from MEA (2005).

Humans are major drivers of landscape patterns

Human-caused loss of Canadian grasslands pre -1990 Climate change basics

1. Huge increases in greenhouse gases caused by human activity

2. Global temperatures are increasing

3. Hydrological patterns are changing (ice sheets, precipitation, ocean currents) 4. Highest impacts are near poles and near ocean

5. Increases in disturbance (storms, fires) are expected

6. Substantial impacts on biodiversity: range, abundance, phenology

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Human-induced emissions have changed the composition of the atmosphere

Many small actions create big impact

Canada: 0.5% of world population 2% of world emissions

Temperature changes vary with location: larger increases on land and near poles

Changes in precipitation patterns also vary with location Sea levels are rising

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Some observed climate-change impacts in Canada

warmer winters earlier springs

less snow, but more winter moisture less summer moisture

Changes in BC: warmer and wetter

Spring is coming earlier in BC A range of climate models all project substantive increases in temperature

Land areas are projected to warm more than the oceans with the greatest warming at high latitudes

Annual mean temperature change, 2071 to 2100 relative to 1990: Global Average in 2085 + 3.1oC

So it’s a little warmer. . .

More hot days

Warmer water

Reduced ice sheets and glaciers

more heat stress tropical diseases moving north wetlands are drying

decreased dissolved oxygen more dead zones coral mortality

changed hydrology altered ocean currents reduced sedimentation

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And precipitation patterns have changed too:

More dry season droughts

Heavier precipitation in wet seasons

desertification drying of wetlands loss of soil biodiversity increased fire

more soil erosion more devastating floods more water-borne disease alteration of river dynamics

Projected impacts of sea level rise of 1 m (many projections are higher)

Sea level rise will damage human populations

salt water intrusion into estuaries

coastal floods

habitat change alteration in food resources

coastal erosion displacement of populations

What’s a species to do?

change phenology (timing of life events: germination, bud burst, hibernation, reproduction) change range die (individual) or go extinct (population or species) evolve

Mountain pine beetles are happy!

cumulative damage

Sea turtles and corals (& other reef organisms) may be in trouble

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Increases in catastrophes

Canadian Fire Statistics

• Incomplete records prior to 1970

• Currently - 9000 fires/year burn 2.6 million ha

• Area burned/year varies:

0.4 to 7.6 million ha

• Fire size

– 3% of fires are >200 ha

– 97% of area burned

CanadaAnnual Area Burned

Year

1920 1940 1960 1980 2000

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8 Projections of Area Burned

CCC –3xCO2

Hadley –3xCO2

Projections based on weather/fire danger relationships suggest a 75-120% increase in annual area burned by the end of this century.

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Life in the Okanagan: water Life in the Okanagan: forests

Life in the Okanagan: forests and grasslands