Climate Vulnerability Assessment of Obtawaing Biosphere Region
Climate Change Impacts in OBR
- Temperatures will increase by 4 to 10 degrees fahrenheit by 2100, with increased warming during winter
- Northern Michigan has already warmed more than 1.5 degrees fahrenheit since 1950.
- This is one of the fastest rates of warming in the US
- Winter snowpack will be reduced by 30-80% by 2100
- More winter precipitation delivered as rain
- More snow melt between snowfall events
- Snowpack is not as deep or consistent
- Lake-effect snowfall may increase in short term, but greater temperatures will convert to rain
- 30 to 50 fewer days of frozen ground sufficient for management during winter by 2100
- The duration of frozen ground has shortened by 2-3 weeks in the pas 70 years
- Cold season soil projected to increase by 1.8 to 5.4 degrees fahrenheit by 2100
- Frost depth to decline by 40 to 80% by 2100 which will lead to greater water in soil and less runoff or greater loss of water in soil because of increased evapotranspiration
- Less snow cover and frozen soil will affect management and ecosystem processes like decomposition and nutrient cycling.
- Growing Season will increase by 30 to 70 days by 2100
- Spring arrives earlier and fall arrives later, so phenology may shift for plant species that rely on temperature ot cue development
- Greater productivity of trees and other vegetation, but only if balance with water and nutrients.
- Intense precipitation events will become more frequent
- Heavy precipitation events will increase in severity and frequency
- Storms in 99th percentile have increased by 42% from 1958- 2016
- Increases in runoff afer heavy precipitation could lead to increased soil erosion
- Large storms to deliver greater rainfall, 20 year return storm to deliver 11-20% more rainfall by 2100
- Soil moisture patterns will change
- Drier soil conditions later in growing season
- Changing precipitation (increased precipitation in the spring and winter and less in the summer) will lead to changing soil moisture regimes
- Longer growing season and warmer temperatures will lead to greater evapotranspiration losses and less availability of soil water later in the growing season
- Climate conditions will increase fire risks by 2100
- Fire risk will increase by 20 to 30% due to increased summer temperature
- Increased probability of wildfires by 2100, especially in boreal, temperate coniferous, and temperate broadleaf forests
- Increased fuel loads from pest induced mortality and blowdown events could increase fire risk.
- Many invasive species, pest, and pathogens will increase or become more damaging by 2100
- Increased temperature and moisture stress will exacerbate stress from invasives, pests, and pathogens
- Warmer temperatures may allow pests, invasives, and pathogens to expand their ranges further north
- These stressors are more damaging in environmentally stressed forests, thus there is potential for synergistic interactions with climate change
- Boreal species will face greater stress
- They will experience reduced suitably habitat and biomass
- They will be less able to take advantage of warm temperatures and longer growing seasons than temperate species.
- Southern or temperate species will be favored
- They will experience more suitable habitat and biomass
- Longer growing season and warmer temperatures will lead to greater productivity for these species.
- Natives like American Basswood, Black Cherry, and White Oak
- Also suitable habitat for species not currently in Michigan
- Such as Black Hickory, Hackberry, and Sycamore
- Temperatures will increase by 4 to 10 degrees fahrenheit by 2100, with increased warming during winter
- Forest productivity will increase by 2100
- Warming temperatures are expected to speed nutrient cycling and increase photosynthetic rates for most trees
- A longer growing season will lead to greater growth and productivity if sufficient water and nutrients available
- Lower productivity in localized areas through disturbances like fires, wind events, pests, and droughts
- Low diversity systems are at greater risk
- Diverse systems have greater resilience to extreme environmental conditions and greater potential to recover from disturbance
- Less diverse communities inherently more susceptible to future changes and stressors
- Diversity of response of a system to environmental change is critical to ecosystem resilience, less diverse systems have less diverse responses
- Species in fragmented landscapes will have less opportunity to migrate
- Habitat fragmentation hinders the ability of trees to migrate to more suitable habitat, especially if surrounding area is non forested
- Mean centers of suitable habitat for trees will migrate 60 to 350 miles by 2100 under high emissions and 30 to 250 miles under lower emissions
- Systems limited to particular environments will have less opportunity to migrate
- Systems confined to particular habitats, like for hydrological regimes, soil types, face barriers to migration
- Sugar maple is limited to soils rich in calcium, so it has less available suitable habitat than if predicted by temperature and precipitation alone.
- Riparian forests are restricted from upland areas because of dependence on seasonal flood dynamics for regeneration and competitive advantage.
- Lowland conifer swamps have a unique mix of species adapted to low pH values, peat soils, and particular water table regimes
- Systems more tolerant of disturbance have less risk of declining
- Wildfire, flooding, and pest flooding are expected to increase, so forest adapted to gap-phase disturbance with stand replacing events every 50 to 150 years are less adaptable to change
- Forest systems that are more tolerant to drought, flooding, and fire are better able to withstand climate change
- The urban heat island effect can exacerbate effects of increasing temperatures
- Urban areas with one million plus people can be 2 to 1 degrees fahrenheit warmer than surrounding rural areas because of heat absorbing infrastructure and waste heat from manufacturing and automobiles
- Impervious cover can exacerbate effects of increased heavy precipitation in urban areas
- Increase in impervious cover can dramatically increase size and frequency of localized flooding
- Extended flooding can stress trees to the point of mortality
- Flooding can lead to secondary attacks by pests and diseases
- Forest composition will change across landscape
- Habitat and biomass of tree species will change and ecosystem composition will change with it.
- Tree regeneration and recruitment will change
- Seedlings are more vulnerable than mature trees to change in temperature moisture and other seedbad and early growth requirements
- But seedlings are more responsive to favorable conditions, so depending on the species, varying results
- Surface water temperatures expected to rise due to warming temperatures
- Summer steam temperatures to increase 1.4 to 7.2 degrees fahrenheit by 2100
- Temperature in cold water stratified lakes to increase 2.9 to 3.02 degrees fahrenheit
- Prolonged warming of surface waters lead to degraded water chemistry, eutrophication, and anoxic conditions
- Warming waters can significantly degrade cold water habitats and aquatic communities, which can lead to reduced growth and increased aquatic mortality especially at younger life stages.
- Inland lakes are warming and continued warming will decrease seasonal mixing of stratified lakes and reduce available dissolved oxygen
- An average warming of 0.34 degrees fahrenheit per decade
- Inland lakes will warm 2.9 to 3.02 degrees fahrenheit by 2100
- Warming waters will increase stratification which leads to anoxic conditions and reducing available dissolved oxygen for plants and aquatic organisms
- Even less dissolved oxygen when aquatic species increase respiration to cope with warming temperatures
- Coldwater fisheries are particularly vulnerable
- Seasonal variation in soil moisture and altered precipitation may influence magnitude and duration of floods
- Increased flood risks threaten ecosystems, wildlife, property, infrastructure, human health, and safety
- More frequent and longer heavy precipitation events will lead to increased flooding, especially when soils are already saturated
- Streamflow events may become more frequent and deliver lower water volumes
- Daily low flows to become more frequent with an annual increase of 17 to 27% by 2100
- Base streamflows reduced with longer growing season and warmer temperatures
- Increased water demand and use to maintain public utility water supply and agricultural requirements will lead to reduced streamflow
- Drier climate conditions alter water balance and reduce baseflow have greatest impact on sensitive systems like head water ephemeral and other small perennial and intermittent systems
- Forest productivity will increase by 2100
Human Vulnerabilities to Climate Change
- Approximately 40 disadvantaged counties in OBR
- Michigan is projected to see a fivefold increase in heat wave days by 2050
- Michigan faces an above average overall summer drought threat
- Nearly 340,000 people live in Michigan’s flood-prone areas.
- Increased aerosols and particulates
- Increased pollen
- Heat related illnesses and deaths.
- Air pollution
- Water and food borne diseases like ticks and Lyme disease.
Coastal Vulnerabilities
- Great Lakes water levels are oscillating abnormally because of erratic precipitation caused by climate change
- Higher rates of precipitation is causing greater flooding
- Rain on snow is contributing to greater nutrients in lakes
Climate Change Impacts on Forests
Major stressors and threats to forests in the region include:
- Fragmentation and land-use change
- Fire regime shifts
- Nonnative species invasion
- Forest pests and disease
- Overbrowsing by deer
Some forest types are favored by climate change:
- Most vulnerable- Upland spruce fir
- Moderate vulnerability- Lowland conifer, Red pine/ White pine, and Jack Pine
- Low vulnerability- Aspen birch, northern hardwoods, lowland/ riparian hardwoods
- Favorable- Oak associations, Barrens