1. The Multidimensionality of Global & Climate Change Global change = interaction
among multiple
environmental change
Beyond Just Air Temperature
stressors, humans caused.
Multiple Environmental Change Stressors (Human Causes)
• Land use alteration/degradation (habitat fragmentation, afforestation)
• Nitrogen deposition
• Biological invasions Caused by humans
• Chemical pollution
• Climate change (multiple dimensions)
Compounding Effects from Interactions
• Synergistic effects between climate change and invasive species
• Impacts on biotic interactions (e.g., pollination networks)
• Multiple drivers complicate understanding of mechanisms
,Mechanisms of Invasive Alien Plants & Climate Change on Ectotherms
• Habitat structure changes: light, radiation, temperature, perches, obstacles, nest
sites, refuges
• Impact on thermoregulation and visibility
• Changes to understory, decomposition, nutrients, fires, hydrology, erosion
• Overall effects on species (movement, adaptation, extinction) and communities
(richness, abundance, composition)
Multiple Variables of Anthropogenic Climate Change
• Temperature (both increases AND decreases!)
• Precipitation patterns, droughts, floods
• Radiation levels (via changes in cloud cover)
• Wind (wind speed, cyclones)
• Sea level rise (loss of land mass)
• Glacier/ice mass loss
• Permafrost degradation
• Changes in timing of seasonality
Compounding Effects Due to Interactions Among Climate Variables
• Drought + extreme heat + low humidity = increased wildfire risk
• Hot weather during dry periods drastically increases stress for mammals and
birds that rely on evaporative cooling
, Dimensions of Climate Change
- Variation in the parameters (temperature, precipitation) through time and space.
can change in magnitude, frequency, timing and duration.
- Different metrics devised to capture these dimensions = vital to assess potential
impacts of climate change.
Local Change Metrics
• Magnitude:
o Anomalies: Difference in temperature at a given locality over time
o Standardized anomalies: Difference standardized by historical climate
variability
o Change in probability of extremes
• Timing:
o Change in seasonality: Difference in the timing of climatic events over time
Regional Change Metrics
• Availability:
o Change in area of analogous climates
o Area of novel climates
• Position:
o Change in the distance to analogous climates
o Climate change velocity
Important Findings on Climate Change Dimensions
• Different dimensions reveal different (sometimes opposing) projections
• Tropics & hot arid regions: Experience novel climatic conditions and extreme
drying/warming events
• Temperate regions: Exposed to all dimensions of change
• Cold regions: Exposed to large-distance or high-velocity shifts in the position of
prevailing climates
Climate Velocity
Definition
• Climate velocity: Vector describing the speed and direction a species would need
to move to maintain its current climate conditions
• Calculated as the ratio of temporal gradient (°C/yr) to spatial gradient (°C/km) =
km/yr
• Ecological meaning:
o Hilly landscape – species distribution = shift short distances to maintain
preferred climate envelope = low velocity (heterogeneous thermal
environment)
o Flat landscape – need to shift longer distances to maintain preferred
climate envelope = high velocity (homogenous thermal environment)
, Local climate velocity = ratio of temporal and spatial gradients of mean annual near-
surface temperature
Types
• Simple: Typically used for a single variable (e.g., temperature) for species with a
primary requirement
• Complex: Used for multiple variables for species with multiple requirements and
dissimilarity thresholds
Applications
• Determining residence time of climates (residents vs. migrating species)
• Identifying climate refugia areas with likely high endemism
• Testing historical species range shifts and predicting future ones
Caveats
• Climate velocity ≠ species movement
• Ignores ecological relevance of the magnitude of change
• Typically presented without uncertainty (potential errors in estimates)
• May project unrealistic suitable habitats
among multiple
environmental change
Beyond Just Air Temperature
stressors, humans caused.
Multiple Environmental Change Stressors (Human Causes)
• Land use alteration/degradation (habitat fragmentation, afforestation)
• Nitrogen deposition
• Biological invasions Caused by humans
• Chemical pollution
• Climate change (multiple dimensions)
Compounding Effects from Interactions
• Synergistic effects between climate change and invasive species
• Impacts on biotic interactions (e.g., pollination networks)
• Multiple drivers complicate understanding of mechanisms
,Mechanisms of Invasive Alien Plants & Climate Change on Ectotherms
• Habitat structure changes: light, radiation, temperature, perches, obstacles, nest
sites, refuges
• Impact on thermoregulation and visibility
• Changes to understory, decomposition, nutrients, fires, hydrology, erosion
• Overall effects on species (movement, adaptation, extinction) and communities
(richness, abundance, composition)
Multiple Variables of Anthropogenic Climate Change
• Temperature (both increases AND decreases!)
• Precipitation patterns, droughts, floods
• Radiation levels (via changes in cloud cover)
• Wind (wind speed, cyclones)
• Sea level rise (loss of land mass)
• Glacier/ice mass loss
• Permafrost degradation
• Changes in timing of seasonality
Compounding Effects Due to Interactions Among Climate Variables
• Drought + extreme heat + low humidity = increased wildfire risk
• Hot weather during dry periods drastically increases stress for mammals and
birds that rely on evaporative cooling
, Dimensions of Climate Change
- Variation in the parameters (temperature, precipitation) through time and space.
can change in magnitude, frequency, timing and duration.
- Different metrics devised to capture these dimensions = vital to assess potential
impacts of climate change.
Local Change Metrics
• Magnitude:
o Anomalies: Difference in temperature at a given locality over time
o Standardized anomalies: Difference standardized by historical climate
variability
o Change in probability of extremes
• Timing:
o Change in seasonality: Difference in the timing of climatic events over time
Regional Change Metrics
• Availability:
o Change in area of analogous climates
o Area of novel climates
• Position:
o Change in the distance to analogous climates
o Climate change velocity
Important Findings on Climate Change Dimensions
• Different dimensions reveal different (sometimes opposing) projections
• Tropics & hot arid regions: Experience novel climatic conditions and extreme
drying/warming events
• Temperate regions: Exposed to all dimensions of change
• Cold regions: Exposed to large-distance or high-velocity shifts in the position of
prevailing climates
Climate Velocity
Definition
• Climate velocity: Vector describing the speed and direction a species would need
to move to maintain its current climate conditions
• Calculated as the ratio of temporal gradient (°C/yr) to spatial gradient (°C/km) =
km/yr
• Ecological meaning:
o Hilly landscape – species distribution = shift short distances to maintain
preferred climate envelope = low velocity (heterogeneous thermal
environment)
o Flat landscape – need to shift longer distances to maintain preferred
climate envelope = high velocity (homogenous thermal environment)
, Local climate velocity = ratio of temporal and spatial gradients of mean annual near-
surface temperature
Types
• Simple: Typically used for a single variable (e.g., temperature) for species with a
primary requirement
• Complex: Used for multiple variables for species with multiple requirements and
dissimilarity thresholds
Applications
• Determining residence time of climates (residents vs. migrating species)
• Identifying climate refugia areas with likely high endemism
• Testing historical species range shifts and predicting future ones
Caveats
• Climate velocity ≠ species movement
• Ignores ecological relevance of the magnitude of change
• Typically presented without uncertainty (potential errors in estimates)
• May project unrealistic suitable habitats
