Transcript Osland_NWLCC_presentation_10_21_2014x

Landscape-scale assessments of
climate impacts to tidal wetlands
along the northern Gulf of Mexico
Michael J. Osland
U.S. Geological Survey, National Wetlands Research Center
Lafayette, Louisiana
U.S. Department of Interior
U.S. Geological Survey
Gulf of Mexico tidal wetlands are
abundant and diverse
Algal mats
(salt flats)
Succulent plants
(salt marsh)
Graminoid
plants
(salt marsh)
Mangrove trees and
shrubs
(mangrove forests)
Foundation species play an important
ecological role
Species that create
habitat and
facilitate the
development of
entire ecological
communities
Foundation species support ecosystem
goods and services
•
•
•
•
•
•
•
Coastal protection/resilience
Carbon sequestration
Fish and wildlife habitat
Nutrient and sediment removal
Trophic linkages to coastal ecosystems
Seafood
Recreation
Source: nps.gov
Source: nola.com
Source: nola.com
Source: tbep.org
Influence of climate on tidal wetland foundation species?
Hot
Temperature
Mangrove Forest
Cold
Herbaceous
Salt Marsh
Dry
Rainfall
Wet
Vulnerability Assessment
Sensitivity
Exposure
Adaptive Capacity
Ecological Tipping Points
Thresholds, stable states, resilience
Unstable
Low
Resilience
Stable
Resilient
Stable
Resilient
Zones of Instability
Osland et al. In press, Ecology
Identification of zones of
instability- sensitive to
climate change
Two Studies
1. Winter climate change: salt marshes vs.
mangrove forest
2. Rainfall change: Ecological transitions across
a rainfall gradient
Winter climate is an important driver of salt
marsh-mangrove forest interactions in the
southeastern U.S.
Mangrove individuals present
How might winter climate change impact
mangrove forest-salt marsh interactions?
Mangrove individuals present
1.
2.
3.
4.
5.
Divide the coast into a grid of cells
Determine mangrove forest presence or absence for each cell
Determine mangrove forest & salt marsh area for each cell (Florida)
Obtain 30-yr climate data for each cell (1970-2000; Maurer et al. 2002)
Develop species distribution and relative abundance models
Mangrove individuals present
The tipping point: salt marsh vs.
mangrove forest
Osland et al. 2013, Global Change Biology
Salt marsh sensitivity to winter climate changeinduced mangrove forest range expansion
LA
Amount of salt
marsh area
within each
state that would
become
vulnerable to
mangrove forest
replacement
TX
FL
GA
SC
Mean annual
minimum
temperature
increase (oC)
that would lead
to mangrove
forest
dominance
Salt marsh sensitivity to winter climate changeinduced mangrove forest range expansion
Mean annual
minimum
temperature
increase (oC)
that would lead
to mangrove
forest
dominance
Study #2: Ecological transition across a
rainfall gradient (in press, Ecology)
How do rainfall regimes affect tidal wetland ecosystems?
Hot
Temperature
Mangrove Forest
?
Herbaceous
Marsh
ChangeSalt
in functional
groups; ecosystem structure
and function
Cold
Change in plant coverage
Dry
Rainfall
Wet
Thresholds, stable states, resilience
Unstable
Low
Resilience
Stable
Resilient
Stable
Resilient
Rainfall: 1970-2000
Mean Annual Precipitation
(mm/yr)
Plant cover transitions along the rainfall
gradient
Osland et al. In press, Ecology
Estuarine level analyses
Osland et al. In press, Ecology
Zone of instability:
sensitive to small changes
in freshwater availability
Zones of instability: small changes in macroclimatic
drivers could lead to landscape-scale ecological
change
Red= high sensitivity to changes in winter temps
Blue = high sensitivity to changes in freshwater
availability
What should be done within sensitive
areas (zones of instability)?
1.
2.
3.
4.
5.
Monitoring networks should be established
Better understanding of historical change
Role of positive feedbacks/microclimate
Implications for good and services?
Implications for adaptation to sea level rise and
other stressors? Resilience?
6. Can management and restoration efforts be
optimized to maximize adaptation?
7. Future-focused models should incorporate
macroclimatic drivers
Zones of Comparative Stability
Green = Potential refuge for salt marsh ecosystem
good and services
What should be done within stable
areas?
1. Gauge whether these areas can serve as
refuges
2. What other aspects of future change may
affect ability to serve as refuges?
3. Any barriers to adaptation to sea level rise
(e.g., urbanization & other stressors)?
4. How can management and restoration efforts
be optimized functionality as refuges?
Thanks to many colleagues that
contributed to this research
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Richard Day
Nicholas Enwright
Tom Doyle
Camille Stagg
Jim Grace
Chris Gabler
Steve Hartley
Andy From
Jennie McLeod
Meagan McLemore
Erik Yando
Ken Krauss
Mark Hester
Jonathan Willis
For more info:
[email protected]