Habitat Fragmentation Active Learning Module
Draft Outline
Objectives
My goals for this module include definitions of habitat fragmentation at different levels
and the consequences of human induced fragmentation on an ecosystem. More
importantly, I want students to take home the idea of how habitat fragmentation affects
ecosystem health and connect class ideas to their own surrounding environments. This
module will include a short lecture, in-class synthesis, and a homework assignment.
How will students be introduced/motivated to this exercise aka “the hook”
I believe a good hook for this learning module will introduce students to the rate of
population growth in front range northern Colorado.
There are now more people living in the Front Range than were in the entire state 10
years ago. Recent estimates project that in 20 years, an additional two million residents
will occupy the Front Range, a growth rate of 65% (CWCB, 2004) - or 43,500 acres
developed per year (Hobbs and Theobald 1998).
Ironically, it is the counties with the richest agricultural soils that are experiencing the
greatest growth pressures. Two of these counties - Larimer and Weld - grew an average
of 36% between 1990 and 2000 (Colorado Demography Department).
Because of these pressures, soaring land and water values make land protection in this
area challenging. Most residents are aware of the loss of agricultural lands and open
space, and of how development pressures continue to alter the landscape and character of
the area.
Agricultural lands and open space are also important areas for wildlife. These areas are
being altered by many different kinds of development. Large parcels of land are being
broken into smaller parcels and then becoming isolated…..habitat fragmentation
Background Material
This module gives both concepts and definitions at the beginning of a “mini lecture” prior
to activity. These concepts can be given from a power point presentation that will
include both pictures and diagrams.
1. Defined - The process by which a natural landscape is broken up into small parcels of
natural ecosystems, isolated from one another in a matrix of lands dominated by human
activities. Fragmentation can be both natural and human induced.
2. Fragmentation is natural (when "natural" it's called heterogeneity): fires, forest insect
disease outbreaks, wind storms, avalanches, soil, slope, aspect, and elevational
differences, etc.
3. Fragmentation is increasing: roads, exurban development, logging, recreation, energy
development.
4. Edge
5. Types of habitat fragmentation:
Regressive fragmentation: Results when habitat is cleared from one direction
and the front edge of habitat is pulled back.
Enveloping fragmentation: Results when clearing surrounds habitat causing it to
contract.
Divisive fragmentation: Results when habitat is bisected i.e. roads
Intrusive fragmentation: Habitat is altered from within
6. Affects of fragmentation on an ecosystem
-Isolation (breeding populations are isolated)=possible extinction
-Reduced area
-Increased edge
7. Species affected by habitat fragmentation include:
a. Area-sensitive species - species with large area requirements, such as bears,
lions, elk, etc. These species have reduced fitness (ability to survive and reproduce) with
reduced area.
b. Edge-sensitive species - species whose fitness is reduced near edges. Three general
reasons for this.
1. Biological reasons - Edge generalist species (species whose
fitness increases near edges). Predators (e.g., raccoons),
competitors (e.g. robins), parasites (brown-headed cowbirds).
2. Abiotic reasons - Climatic variables (e.g., temperature, wind,
solar radiation, relative humidity) change near edges. These, in
turn, can affect the fitness of edge-sensitive species
3. Human reasons
c. Dispersal-sensitive species - species whose fitness is reduced with decreasing
connectivity of isolated ecosystem patches.
*Specific Examples will be given for each species above along with characteristics.
8. General reserve design: A well planned reserve should include three types of area.
a. Core
b. Multiple use (buffer zone)
c. Corridors
d. Matrix (area surrounding reserve) should also be considered but not necessarily
considered in a reserve design.
* Examples again will be given along with pictures so students can see what the different
reserve areas look like. Other reserve guidelines should also be discussed. For example,
a habitat island linked together is better than isolated islands.
Active Learning
Students will then break up into small groups (5-6 people). They will be taking on the
role of habitat managers in a reserve design project. Their goal as a land manager will
include the design of a reserve to protect all three species affected by habitat
fragmentation. They should begin by sketching out a reserve design in class including
buffers, core areas, corridors, etc. The groups will then finish their design out of the
classroom. The designs can be drawings, 3-Dmodels, computer stimulations, etc. A short
paragraph will also be handed in to describe how the model is protecting the species of
concern.
How does this module connect back to ecology?
Ecology looks at the processes influencing the distribution and abundance of organisms.
This module will look at anthropogenic influences of wildlife distribution in a fragmented
habitat. The synthesis will then ask how the distribution of wildlife affects overall
abundance and what are the solutions?