Transcript No Slide Title

Our Abundance and Use of
Resources Are Changing
(Vitousek 1994)
(World Population Clock,
Population Reference Bureau
2002 http://www.prb.org/)
Future Projections
http://www.un.org/esa/population/publications/wpp
2000/highlights.pdf
Transformation to a Human
Dominated World
• Global Environmental Change
–
–
–
–
–
–
–
Land Transformation
Atmospheric Gases
Altered Biogeochemical Cycles
Persistent Organic Compounds
Harvesting Natural Populations
Biological Invasions
Altered Selective Regimes
Certainty and Uncertainty
• “While ecologists involved in management or
policy often are advised to learn to deal with
uncertainty, there are a number of components of
global environmental change of which we are
certain—certain that they are going on, and
certain that they are human-caused.”
• “…addressing global change will require active
collaboration with a wide range of scientists
outside our field.., but..it is our responsibility to
take the lead in dealing with major components of
global environmental change.”
(Vitousek 1994)
(Vitousek et al. 1997)
Medicine /
Biotechnology
Novel
Selective
Regimes
Changed
Evolutionary
Trajectories
(Modified from Vitousek et al. 1996 to include Palumbi 2001)
(Vitousek et al. 1997)
Changes in Global
Biogeochemical Cycles
Changes in Carbon and Nitrogen
(Vitousek 1994)
Effects of Changing Nitrogen Cycle
•Increased nitrate leaching
•Emissions of greenhouse gas
(N2O)
•Enhanced carbon storage
•Forest dieback
•Change balance of plant
communities in favor of nitrogendemanding species which can lead
to homogenization of floras and
reduced ß diversity
•Increase net primary productivity
and biomass, but decrease ά
diversity
Changes in Land-use and Land- cover
• Global changes:17001990 (Meyer and Turner 1992)
(Lambin et al. 2001)
–
–
–
–
–
–
–
–
Cropland
Irrigated Cropland
Closed Forest
Forest and woodland
Grassland/pasture
Lands drained
Urban settlement
Rural settlement
+392 - 466%
+2400%
-15.1%
-14.9%
-1%
1.6 x 106 km2
2.5 x 106 km2
2.1 x 106 km2
(McKinney 2002 BioScience 52:883-890)
Contrasting Various Land Covers
High
Urbanization
Effect of
Agriculture Fragmentation
Persistence
of
Change
Low
Timber
Harvest
High
Low
Similarity of Matrix to Natural Habitat
(Marzluff and Ewing 2001)
Study Area: Suburban to Wildland
Gradients Along I-90 Corridor
(Robinson et al. 2005. Landscape and Urban Planning 71:51-72)
Dominant Landscape Definitions
• Urban – Buildings cover majority of land; includes dense
single/multi-family housing on small lots (<.02 ha), commercial &
industrial uses
• Suburban – Moderate
to high density, SFH predominates on
small to moderately sized lots (0.1 – 1 ha)
• Rural – Sparse single family settlement on moderate to large lots
and towns in matrix of agricultural lands (0.5-20 ha)
• Exurban – Similar to rural, but settlement is in a matrix of natural
vegetation; little or no commercial agriculture present (0.2-20 ha)
• Wildlands – Unsettled lands that may occasionally include
isolated dwellings
There were dramatic
changes in Dominant
Landscape
• Suburban & exurban
lands increased by
756% & 193%,
respectively
• Rural becomes
suburban
• Wildland becomes
exurban
• Average patch size:
– Suburban & exurban
increases
– Rural & wildland
decreases
– Fragmentation of
forests
1974
1998
Transition Between Landscapes
along Seattle’s Urbanizing Fringe
Total Study Area
Is 45,282 ha
.07
.54
.29
Rural
Suburban
.92
.22
.77
.14
Exurban
.16
Wildland
<5% transition
.80
Loss of Wildland due
to expansion of
Exurban
development
(green hatching)
Loss of Rural lands
due to expansion
of Suburban
development
(yellow hatching)
Rural
A Portion of the
Study Area in
1974 and
Suburban
1998
Changes in
vegetative cover
1974
1998
• Forested areas
have become more
fragmented
Decline in Interior Forest
Interior Forest
•Area > 200m from
settlement decline 60% from
29,721 ha in 1974 to 17,697
ha in 1998
•Average size of interior
patches dropped 39% from
2701ha to 1040 ha
•No patches remain within
suburban landscape that are
>200 from settlement
•Total edge declined (from
913 Km to 644 Km) because
patch size decreased
(Hansen et al. 2005. Ecological Applications 15: 1893-1905)
Variations on the Theme
• Forest generally decreases with increasing
population density
– Not so around Chicago (and much of eastern US) where
it has increased due to regrowth of logged areas
– Not so in Jitai Basin, China where government policy
mandates reforestation
• Agriculture generally declines with increasing
population density
– Clear around Chicago and Seattle
– Not so in south Florida where wetlands are drained to
increase agricultural land (primarily sugar cane)
(National Academies of India, China, US 2001)
Ecological Effects of Land-cover
and Land-use Change
•
•
•
•
Trace gas emissions (CO2, methane, nitrous oxide)
Climate change (by above and direct change in C)
Reduced diversity of native species
Habitat quality reduced by fragmentation and
increased edge
• Reduced soil quality resulting from erosion
• Increased fertilizer
• Changed water quality and flow
(Meyer and Turner 1992; Dale 1997)
Ecological
Cost of
Intensive
Agriculture
(Donald et al. 2001)
In Seattle, Land Conversion Reduces
Plant Species Diversity
Forb Richness (P=0.01)
Shrub Richness (NS)
Tree Richness (P <0.001)
18
Diversity of Plants
(species/point)
16
14
12
10
8
6
4
2
0
0
20
40
60
80
100
Proportion of Landscape in Forest
(Hansen et al. 2005. Ecological Applications 15: 1893-1905)
Ditto for Birds
40
30
Number of Bird Species
20
10
0
0
20
40
60
80
100
Percentage of Forest in Landscape
40
35
30
25
20
15
10
5
0
20
40
60
Age of Development
80
100
Bird Species
Richness increases
with increasing forest
and declines with
increasing age of
development
•(R2=44.7%, P<0.001)
More Detail on Bird Responses
Marzluff, J. M. 2005. Urban Ecosystems 8: 155-175.
Expected
Changes
(Heppinstall et al. in press)
Bird Changes
40
Total Species Richness
35
Development Partition
Urban
30
Transition
Rural
Four County
25
20
15
Early Successional Richness
Native Forest Richness
10
Synanthropic Richness
5
20
03
20
09
20
11
20
15
20
19
20
23
20
27
20
03
20
09
20
11
20
15
20
19
20
23
20
27
20
03
20
09
20
11
20
15
20
19
20
23
20
27
20
03
20
09
20
11
20
15
20
19
20
23
20
27
0
Spatial
Changes
Winners
And Losers
Change in Global Climate
• 0.6°C increase in average global temperature over
last 100 years
• Projected to continue at rapid rate (1.4-5.8°C by
2100)
• Increase CO2 is a primary reason for Global
Warming
• Changed nitrogen cycle (increased N2O) also
plays a role
• Land use change is less important
Effects of Global Warming
• Largest effects expected in north, where temp
changes are greatest
– Change in density or distribution
• (75 – 81% of studies show expected change; 6km/decade
north)
– Change in timing of events
• Migration, flowering, egg laying (87% of studies confirm)
– Change in composition of community
• (74 – 91% confirm more northern species)
– Change in morphology
– Change in gene frequency
(Root et al. 2003, Parmesan and Yohe 2003))
Most Everyone is Doing it Earlier
Timing of spring events
•All on average 5 days
earlier per decade
•Breeding of murres 24
days earlier per decade
•Breeding of fowler’s
toad is 6.3 days later
(Root et al. 2003)
Global Warming and Disease
•Increase disease severity
•Increase vector distributions
•Increase abundance and distribution
of macroparasites
•Disrupt some diseases
•chytrids and iridoviral diseases that affect
amphibians
•Modify seasonal pattern of pathogens
(Harvell et al. 2002)
Exotics
Cause
# Endangered
Interactions with nonnatives
Urbanization
Agriculture
Outdoor recreation, tourism
Ranching
Water diversions
Modified fire regimes,
silviculture
Pollution of water, air, soil
Energy exploration
305
275
224
186
182
161
144
Industry and military
131
(Czech and Krausman 1997)
144
140
(Vitousek et al. 1996)
(Vitousek et al. 1996)
Snails and Snakes
(Vitousek et al. 1996)
Land-use Changes May Facilitate Invasions
(Vitousek et al. 1996)
Exotic ground cover
increases with age of
development and
reduction in aggregation
of forest (R2=19.4%, P=0.002)
70
60
Percentage of Ground Cover Exotic
50
40
30
20
10
0
0
20
40
60
80
100
Age of Development
60
50
40
30
20
10
0
30
40
50
60
Aggregation of Forest
70
80
•Variation may be due to
human behavior, values,
or policies
Parks are Not Immune
• Pigs, goats, burros, mountain goats
• Lake, brook, and rainbow trout
• White pine blister rust
– 100 yrs ago from Europe nurserys
– Whitebark pines in Glacier, Yellowstone, Grand
Teton
• Loss of important grizzly food
• Barred owls and spotted owls
Consequences of Exotic Invasions
• Newly introduced species can act as vectors of
disease
– Asian tiger mosquito
• Invaders can drain resources
– Apple snail ($28-45million in Philippines in 1990)
• Invaders can alter ecosystem processes
– Myrica faya in Hawaii facilitates succession on volcanic
soils by fixing nitrogen
• Reduce Biological diversity
– Gypsy moths, chestnut blights, etc.
• Promote extinction
– Importance to ESA listing
(Vitousek et al. 1996)
Are We Recreating Pangea?
(Vitousek et al.1996)
Changing the Course of
Evolution
• Accelerate evolutionary change
– Fish size related to net mesh
– House sparrows diverge to match
newly colonized environments
– Resistance in diseases and pests
• House flies were becoming resistant
to DDT before Müller got his Nobel
for discovering DDT
(Palumbi 2001a, b)
Debate over Direct and Indirect
Effect of Population, per se
• Is IPAT too simple?
• Other factors may mediate or determine the effect of
humans
• Malthus vs. neoclassical economics
– will we exceed k or will we keep increasing k?
• Population may be large scale factor
– Increasing population demands more resources
– But local social, institutional, political, and economic factors determine
where and how resources are taken
» Globalization allows disconnect between sources of demand and
location of production
(Meyer and Turner 1992; Lambin et al. 2001; National Academies of India, China, US 2001)
• Land change appears to result from:
– “individual and social responses follow from changing
economic conditions, mediated by institutional factors.
Opportunities and constraints for new land uses are
created by markets and policies, increasingly
influenced by global factors. Extreme biophysical
events occasionally trigger further changes. Various
human-environment conditions react to and reshape the
impacts of drivers differently, leading to specific
pathyways of land-use change.” (Lambin et al. 2001)
Global Change and Biodiversity
Continental extinction
rates have increased
from 10-7 to 10-4
species/species/year
Nott, et al. 1995. Current
Biology 5:14-17
(Chapin et al 2000)
Does it Matter?
• Hell Yes
– Much is unknown, so save the parts
• Leopold’s advice for intelligent tinkering is to save all
the parts
– How many rivets can we pop?
• Ehrlich and Ehrlich 1983. Extinction: the causes and
consequences of the disappearance of species. New
York: Ballatine Books
– Biodiversity is connected to ecosystem function
• Loreau 2000; Tilman 2000; Chapin et al. 2000.
(Chapin et al. 2000)
(Chapin et al. 2000)
(Chapin et al. 2000)
Expected Drivers of Changing Biodiversity
(Sala et al. 2000)
Spatial Extent of
Expected Changes
(Sala et al. 2000)