BIO220Winter2025_Lecture12_1slideperpage

Climate Effects on Organisms, Phenology, & Interactions

• Basic Ecological and Evolutionary Biology (EEB) principles predict several outcomes due to climate change:

  • Phenological Changes: Alterations in the timing of biological events.

  • Migrations:

    • Latitudinal: Movement toward the poles.

    • Altitudinal: Movement toward higher elevations (mountaintops).

  • Population Dynamics: Changes including population growth, decline, and potential extinctions.

  • Evolutionary Change: Adaptations in species over time due to environmental pressures.

Historical Context of Migration and Range Shifts

• Migration and range shifts are documented throughout geological history:

  • Species Dispersion: Some species have the inherent ability to disperse over geographical distances.

  • Natural Changes: Historical climate changes typically occurred at a pace allowing species adjustments to their ranges.

  • Evolutionary Responses: Strong natural selection can lead to rapid evolutionary responses to changing environments.

  • Anthropogenic Changes: Human-induced climate changes often occur too rapidly, hindering species' abilities to adapt or migrate effectively.

Bumble Bees and Climate Impacts

• The Rocky Mountain Biological Laboratory studies bumble bee species and their adaptations.

Snowfall and Climate Data

• Mean Snowfall: Average snowfall since 1975 is approximately 1.1 m, with a range from 4.7 to 16.4 m, indicating variability influenced by climate.

Research on Bumble Bee Species

• Graham Pyke's Altitudinal Transects:

  • Censuses conducted to monitor bumble bee species from 1974 to 2025, noting potential shifts in distribution due to climate change.

• Repeated Censuses: Observations by U of T ROP399 students in 2006-2007 examined changes in bumble bee populations over time.

Shift in Bumble Bees' Elevation and Species

• Data Analysis: The fraction of bumble bee species across elevations indicates shifts in distribution.

  • Upward shifts of 250 m can equate to shifts of approximately 800 km latitudinally.

General Climate Change Figures

• According to Lenoir et al. (2008) in Science, species generally exhibit upward movement in elevation as climate warms, despite precipitation showing no significant trend.

Specific Shifts in Species

• Animal Range Shifts:

  • Various species, including spiders, ground beetles, butterflies, and grasshoppers, demonstrate shifts in their northern range limits.

  • Average shifts: Northern limit shifts by 16.9 km/decade; upper altitudinal limits by 11.0 m/decade.

Birds and Their Responses to Climate Change

• Research (Freeman et al. 2018) indicates that an area experiencing a 0.4°C rise in temperature without significant land use changes may lead birds to shift ranges.

Ecological Niche Modeling

• Species' Range and Ecological Modeling: An approach to predict potential shifts involves understanding current species distributions and how suitable conditions may change over time due to climate.

Conservation of American Pika

• Adaptations: American pika, a species adapted to cold high mountains, are under threat from rising temperatures exceeding ~27°C.

Modeling Extinctions due to Climate Change

• Studies on Montane mammals in the Great Basin predict extinctions based on habitat loss associated with rising temperatures.

Historic Population Resamples of Pikas

• Research from 2003 updates the status of pikas, finding extirpation in 7 out of 25 mountain ranges surveyed.

Pronghorn Antelope: Migration Challenges

• Migration Corridors: Pronghorn herds traverse areas impacted by human industry, raising concerns for their migratory paths and survival.

• Speed and Evolution: Noted as the fastest land mammals in North America, pronghorn evolved unique traits related to their speed.

Climate Change and Animal Migration

• Human-altered landscapes create additional hurdles for species like pronghorn attempting to migrate due to climate impacts.

Extinction Due to Climate Change

• Bramble Cay Melomys: This rodent species is cited as the first mammal confirmed extinct due to human-driven climate change, primarily from rising sea levels.

Population Decline Insights

• Historical sightings and population estimates reveal a drastic decline of Bramble Cay melomys over the years, leading to extinction by 2014.

Genetic Responses to Climate Change

• The study of genetic polymorphisms in species provides insights into evolutionary adaptations linked to climate shifts, such as changes in pigmentation.

Summary of Climate Change Effects

• Global climate change impacts organisms through migration, phenology, range limits, and evolution, with overwhelming evidence supporting anthropogenic influences and biological responses.

Critical Questions on Climate and Society

1. Why do humans push natural systems to their limits?

2. How can we monitor changes if there is no direct indicator?

3. What is our collective responsibility to address these changes?

4. How do we alter social structures to enhance long-term gains?

Short-Sightedness Analogy

• Antagonistic Pleiotropy in Nature and Politics: Just as natural selection may favor short-term advantages despite long-term costs, human political processes often prioritize immediate benefits over sustainable solutions, presenting a challenge for legislative reform.