Chapter 2. Diagnosis and goal setting
Diagnosis and goal setting results in a conceptual
ecological model, which is a graphical representation of
the stressors and their ecological effects
Ex. Figure 2.1-Veldt grass, an introduced South African
grass, is a stressor that causes a decline in Australian
species
Figure 2.1 Conceptual ecological model for 34 ha of degraded woodland, Kwinana, Western
Australia
Drivers of ecological change
1.
2.
3.
4.
5.
6.
Habitat conversion
Pollution
Overexploitation
Introduced species
Climate change
Natural drivers like drought or disturbances caused by
fires, floods, hurricanes, or volcanoes
Ex. Habitat conversion and subsequent pollution were the
drivers that caused multiple stressors which caused
ecological effects and affected ecological attributes
Figure 2.2- Biscayne Bay, Florida
Figure 2.2 A conceptual ecological model of Biscayne Bay (Florida, U.S.) used to assess the
potential environmental impacts of resource use
Drivers of Ecological Change- 1. Habitat Conversion-Terrestrial
Figure 2.3 Approximately one-fourth of the Earth’s ice-free terrestrial surface is now cultivated
Drivers of Ecological Change- 1. Habitat Conversion-Aquatic
-aquaculture of fish and shrimp have caused 1/3 of the
coastal mangrove forests to be lost in the past 50 years
-40% of the worlds population lives 50 km from coast and
industry, urbanization, resort development seawalls,
bridges, and jetties alter water and sediment movements
Mangrove pneumatophores at
Boca Chica on the Texas Coast.
It is the only place in Texas with a
mangrove forest or mangal.
Drivers of Ecological Change- 2. Pollution-Industrial sources
-result from energy production, manufacturing, mining,
transportation, and waste incineration
-metals as well as spent nuclear fuel from energy
production are toxic
-chemicals like polycyclic aromatic hydrocarbons (PAH)
(from leaking oil and runoff; carcinogens), 150,000
synthetic chemicals with 1000s more manufactured each
year in pesticides, solvents, acids, dioxin (chlorinated
hydrocarbon that is toxic to humans formed during
incineration and paper bleaching), phthlates (chemical
used soften plastic toys that may be toxic and banned in
2008).
Drivers of Ecological Change- 2. Pollution-Agricultural and human habitation sources
-pathogens from livestock that in some cases can infect
humans (anthrax, worms)
-salts from feeds and fertilizers can affect soils
-pharmaceuticals like hormones and antibiotics cause
health problems with reproductive systems and bacterial
resistance
-organic matter, fertilizers as well as nitrogen and
phosphorous compounds cause eutrophication
-ash, particulates, and carbon dioxide contribute to
respiratory problems and climate change Table 2.2
Table 2.2
Drivers of Ecological Change- 3. Overexploitation
Figure 2.4 The Great Barrier Reef Marine Park designated no-fishing zones to allow populations of
fish to recover like this Australian coral trout
Drivers of Ecological Change- 4. Species Introductions
Figure 2.5 Burmese pythons, such as the one held here by a park ranger, are popular pets in the
United States and have created major ecological problems in Everglades National Park
Drivers of Ecological Change- 5. Climate change
Drivers of Ecological Change- 6. Natural drivers
-natural disturbances like hurricanes, floods, fire, or
volcanic eruptions are major drivers of ecological change
-typical pattern of disturbance for an ecosystem is termed
the disturbance regime Ex. Prairie pothole wetlands
require drought once a decade so plant species that
cannot germinate underwater can become established
-humans have changed the natural disturbance regimes of
many ecosystems Ex. flood control structures on rivers
and fire control policies
-ecosystem changes that are novel, too frequent, or too
extensive cause unstablity
Figure 2.6 (A) The hydrology of Tram Chim National Park is managed to mimic historic flood
pulses. (B) Flooded wetlands, provide habitat for many waterbirds and pulses maintain vegetation
Figure 2.7 Ecosystem disturbances (represented by blue dots) vary in frequency (vertical axis) and
area (horizontal axis). Forest fires and tree gaps are less frequent relative to recovery time or
disturb smaller portions than human-caused disturbances like smelter damage.
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Population declines
Influenced by three factors:
1. Environmental stochasticity –caused by six drivers
2. Demographic stochasticity –erratic changes in birth and
death rates of individuals
3. Genetic events
- As populations decline there may be fewer alleles, less
heterozygosity (Figure 2.8), and more maladaptive
alleles. Natural selection can limit the incidence of these
and promote adaptive alleles but small populations are
more susceptible to inbreeding and genetic drift events
like the founder effect
-the synergistic impact of negative effects of 1-3 can lead to
an extinction vortex
Figure 2.8 (A) An allele is one form of a gene. (B) Each progeny inherits two alleles for every gene,
one from each parent
Figure 2.9 The Tasmanian devil is a carnivorous marsupial endemic to the island of Tasmania and
is in danger of extinction due to low genetic diversity and inability to combat a fatal disease
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Habitat fragmentation (HF)
Figure 2.10 Deforestation in southern Bahia, Brazil has decreased biodiversity and adversely
affected river water quality
Figure 2.11 Four different types of spatially structured populations. A nonequilibrium
metapopulation (mp) loses its ability for migration as patches are lost and mp cease to persist
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Introduced species that are invasive or form hybrids
Figure 2.12 Hybridization between the native California tiger salamander and an introduced tiger
salamander yields hybrid progeny with a survival rate higher than that of either parent species
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Changes in species interactions
Figure 2.13 A dune slack wetland is flanked by active dunes, some of which are being stabilized by
woody vegetation. This woody vegetation is periodically removed to restore rare species that carry
on species interactions within wetlands formed by shifting sands
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Changes involving disturbance and succession
Ecological effects caused by the 6 drivers (habitat, pollution, overexploitation. introduction, climate,
and natural drivers) - 1. Population declines 2. Habitat fragmentation;
3. Spread of introduced species 4. Changes in species interactions; 5. Changes in disturbance;
6. Changes in trophic structure
Changes in trophic structure
Figure 2.14 Changes in trophic structure with increasing nutrient loading in shallow temperate
lakes in Europe
Figure 2.15 The Minneapolis Chain of Lakes is surrounded by the city of Minneapolis and has
become degraded by phosporous in stormwater runoff, which dramatically changed the trophic
system
Ecoregions and Landscape analysis
Ecoregions-geographic units corresponding to natural features
Ecoregions and Landscape analysis
Landscape-within an ecoregion, ecosystems and human
uses form repeated patterns
-landscape analysis begins by delineating boundaries of
the assessment area Ex. Problems related to nutrient
transport, soil erosion, and flooding may involve
landscape analysis of a drainage basin Fig. 2.16
-may center on a site of interest based on rare or
endangered species like rhinos and tigers in Chitwan
National Park in Nepal, where landscape analysis was
used to create buffer zones and restore forests in these
areas Fig. 2.17
Figure 2.16 A drainage basin is the land that can contribute surface runoff or outflow to a waterbod
like Hunters Creek in Rocky Mountain National Park in Colorado
Figure 2.17 The government of Nepal encouraged reforestation and sustainable forest
management within buffer zones around Chitwan National Park to improve tiger and rhino habitat
Ecoregions and Landscape analysis
Landscape pattern (structure) refers to the configuration of
different patches within the landscape and is usually
represented using maps created with geographic
information systems (GIS)
-GIS depicts patches of natural ecosystems or humanmodified areas as well as linear features called corridors
like rivers and roads Fig. 2.18
-landscapes may be categorized by degree of habitat
destruction, connectivity, and level of modification into
four levels of habitat destruction Fig. 2.19
Figure 2.18 Within a landscape, patches (P) are tracts with different land covers; corridors (C) are
linear features such as rivers, roads, and fence lines
Figure 2.19 Landscapes can be classified by degree of habitat destruction and the connectivity and
level of modification of the remaining habitat
Site Analysis
Baseline survey-current state of an ecosystem using data
from field surveys
Reference sites-intact ecosystems used as comparisons to
restored or managed sites Fig. 2.20
-plants are often described by mapping vegetation
communities and by compiling plant lists
-animals are surveyed in a similar fashion when sessile but
mobile animals are surveyed to determine whether
species are residents, use the site for breeding, rearing
young, migration, or seasonally
-some species become rare because of human actions and
others have always been rare Table 2.3
-population viability analysis is used to determine if rare
populations might persist using demographic data Ex.
Tasmanian devil, p. 543
Figure 2.20 Reference and managed forests in the Upper Peninsula of Michigan
Table 2.3
Assessment of Ecological Resilience
Ecological resilience-capacity of an ecosystem to withstand
change or to recover after disturbance
-conferred by adaptations possessed by the species within
an ecosystem that allow them to rebound after major
changes
-extent of landscape alteration affects resilience Fig. 2.21
Figure 2.21 As the degradation of a restoration site and surrounding landscape increases,
likelihood of rapid and full ecological restoration declines (indicated by size of circles)
Assessment of Ecological Resilience
Resilience and response to stress can be characterized as
one of three models:
Figure 2.22 Models of three potential recovery pathways
Assessment of Ecological Resilience
How do we know if an ecosystem fits a model that has a
high chance of successful recovery?
-tools have been developed for particular regions and
ecosystems by researchers that have worked in areas
Ex. Obura and Grimsditch (2009) developed a resilience
assessment tool for coral reefs that uses 61 resilience
indicators that cover aspects of nine factors: benthic
cover, physical condition of the substrate and water,
coral condition, coral population viability, coral
associates, fish groups, connectivity to the seascape, as
well as human impacts and management capacity Fig.
2.23
Figure 2.23 Measuring coral recruitment to assess the status of coral populations for a resilience
assessment
SMART goals-Specific, measurable, achievable, reasonable, and time-bound
Specific-clearly capture a community or species to target
for restoration
Ex. Restore marsh or grassland rather than just vegetation
or improve habitat for a focal (flagship) species or group
of species. In the restoration of Sweetwater Marsh in
CA, the goal was to restore marsh vegetation to improve
habitat for the light-footed clapper rail, a focal bird
species
Measureable-Quantify levels of restoration and establish
ways to evaluate progress toward goals. How does it
compare to a reference ecosystem?
Achievable and Reasonable-Base goals on realistic
assumptions.
Time-bound-Goals should specify the amount of time it will
take to achieve them.
Goal setting for large-scale and high-risk restorations
Backcasting-a method for setting incremental goals to
solve problems that will require long-term commitments
and be strongly influenced by external forces with high
potential to impede progress.