CONS 302: Module 5

External causes of climate change

Solar activity, Earth's orbit, Meteorites.

Internal (Natural) causes of climate change

Feedback (processes affecting climate forcing), Volcanic eruption, Chance.

Internal (Anthropogenic) causes of climate change

Emissions of greenhouse gases, Particles/clouds, Land change.

Natural Greenhouse Effect

With natural GHGs, the Earth's temperature is 15°C; without them, it would be -18°C.

Intensified Greenhouse Effect

Human activities release more greenhouse gases, causing less heat to escape into space and more to be re-radiated back to Earth.

Major driver of climate change

The increase in CO₂ is believed to be the major driver. Humans have increased atmospheric CO₂ concentration by more than a third since the Industrial Revolution.

RCP (Representative Concentration Pathways)

GHG concentration scenarios used in the IPCC Fifth Report (e.g., RCP8.5, RCP4.5, RCP2.6).

Radiative forcing values

The difference between incoming energy and outgoing energy (in W/m²). The RCP values (2.6, 4.5, 6.0, 8.5) represent this forcing by the year 2100.

SSP (Shared Socioeconomic Pathways)

The five socioeconomic scenarios used in the IPCC Sixth Report (e.g., SSP1: Sustainability, SSP3: Regional Rivalry, SSP5: Fossil-fueled Development).

Paris Climate Agreement (Goals)

To keep a global temperature rise this century well below 2°C and to pursue efforts to limit the temperature increase to 1.5°C.

Mitigation (Climate Change)

Reducing climate change by (1) Reducing sources of greenhouse gases and (2) Enhancing the “sinks” that accumulate and store these gases.

CCUS facilities (Carbon capture, utilisation and storage)

A mitigation measure to capture carbon emissions.

Forests (Climate Change Mitigation)

Forests absorb 1/3 of carbon emissions from fossil fuels and provide green materials (like wood) to reduce the use of CO₂ emission-intensive materials (like cement and steel).

Forests as Carbon Sink vs. Source

Forests can serve as a carbon sink only when they are healthy and productive. They can become a carbon source when they suffer from maladaptation.

Tree performance (formula)

Tree performance = G (Genetics) + E (Environments).

Climatic Niche

The range of climatic conditions that a species is adapted to.

Climate Change Challenge for Trees

Climate change is causing a mismatch between the current climatic niche of trees and the future climate, leaving them vulnerable.

Ecological Niche (Grinnell, 1917)

The habitat requirements of a species for it to survive and reproduce.

Ecological Niche (Hutchinson, 1957)

Expanded the habitat into multiple dimensions, with each dimension representing the range of some environmental condition required by the species.

Fundamental Niche

The full range of (physical) environmental conditions that a species can occupy and use (survive, grow, regenerate, evolve).

Realized Niche

The range of conditions actually occupied by a given species, which is a part of the fundamental niche limited by factors like interspecific competition, migration limits, and physical barriers.

Climate Niche Models (CNMs)

Analytical (or correlative) ecological models based on the relationships between species distribution and climate variables. Also known as bioclimate envelope models or species distribution models (SDMs).

Niche conservationism

The ecological niche of a species is not likely to change, at least in the near future.

Building CNMs (requirements)

CNMs are constructed based on (1) Species occurrence data, (2) Climate variables, and (3) Machine-learning algorithms.

Natural population responses (to climate change)

Natural migration from the leading edge, Adaptation over generations using standing variation and gene flow, Lagging edge population extirpation.

Management and Conservation strategies (for climate change)

Assisted migration, In situ conservation and assisted migration, Ex situ conservation and introduction of new species.

BEC (Biogeoclimatic Ecosystem Classification)

A system in BC that classifies 16 ecological zones and 105 subzones, serving as a foundation for forest resource management (e.g., species selection for plantation).

Gridded climate data (limitation)

Represents the average of each grid (e.g., 4km x 4km), which can be inaccurate for complex terrain.

Scale-free climate data

Climate data that is not limited to a grid and can be downscaled to specific locations, such as through dynamic local elevation adjustment.

Dynamic local elevation adjustment

A method to estimate the lapse rate (change in temperature with elevation) based on the values from neighboring tiles, allowing for more accurate local climate data.

Genecology

The study of intraspecific genetic variation in relation to environmental conditions (genetic variation-environment relationships within a species).

Ecological genetics

The study of genetics in natural populations; the study of how ecologically relevant traits evolve in natural populations.

Provenance

The place of origin; seed source or seed origin.

Population (Genecology)

A group of individuals of the same species that live in a particular geographical area and can interbreed; individuals from the same provenance.

Genecology major findings (from yarrow experiment)

(1) Variation among provenances at each site, (2) Variation is related to the distance moved, (3) G x E (Genetics x Environment) interaction.

Genecology (Operational objectives)

To determine how far seed can be moved, to select optimal provenances, and to delineate geographic breeding zones.

Why genecology is still performed on trees

(1) Planting and breeding materials are still collected from nature, (2) Large genetic variation among natural populations, (3) Distributions span a broad range of environmental conditions.

SPUs (Seed Planning Units)

The basic unit for tree improvement programs in BC, delineated based on results of provenance trials.

Short-term genecology experiments (traits studied)

Phenology, cold hardiness, and drought tolerance, as they are suitable adaptive traits.

Genetic Cline

a geographic or climatic pattern

of change in an allele frequency or a trait

Geographic vs. Climatic variables

Geographic variables (latitude, longitude, elevation) are indirect measures of climate and are not useful for climate change adaptation. Climatic variables (temperature, precipitation) are direct environmental factors and selection forces.

Transfer functions (TF)

Relate performances of populations to climatic transfer distance (CTD) at one test site; they reflect the genetic effects of populations.

Climatic Transfer Distance (CTD)

CTD = Site climate - seed source climate.

General transfer function (GTF)

A transfer function with data pooled across all test sites. Its problem is that patterns at different sites may cancel each other out.

Genecology function (GF)

Relates performances of populations to a climatic variable of the seed source; reflects genetic effects but may not work in other environments.

Response functions (RFs)

Relates the performance of one population to climatic variables of the test sites.

Universal response functions (URF)

Relates performance to both seed source and test site climate, integrating environmental and genetic effects to predict the performance of any provenance at any planting site.

Conservation Genetics

A subfield of population genetics that aims to understand the dynamics of genes in populations, principally to avoid extinction.

Three fundamental levels of biodiversity

Genetic diversity, Species diversity, Ecosystem diversity.

Keystone species

Species that play central roles in ecosystem function, upon which many other organisms depend (e.g., White Bark Pine).

Threats to genetic variation of forest trees (Human)

Habitat loss, Deforestation, Fragmentation, Invasive species, Climate change.

Threats to genetic variation of forest trees (Genetic impacts)

Limited gene flow, inbreeding, accumulation of deleterious mutations, genetic drift.

Genetic factors in conservation

Genetic effects of small population size, Genetic drift, Inbreeding and inbreeding depression, Hybridization, Local adaptation.

Genetic drift

Loss of genetic variation due to random sampling, which leads to the loss of some alleles.

Hybridization (impacts)

Can result in genetic contamination and introgression, and possible outbreeding depression.

Local adaptation

A mechanism whereby a population of organisms evolves to be more well-suited to its local environment than other members of the same species that live elsewhere.

Conservation units

Ecosystem classifications (like BEC zones) can be used as conservation units to capture among-population variation. Genetic conservation is implemented at the population level.

In situ conservation

The conservation of a species in its natural habitat and the maintenance and recovery of viable populations in their original place (e.g., nature reserves, parks).

Ex situ conservation

The conservation of populations and species outside their natural habitats (e.g., Svalbard Global Seed Vault, BC Tree Seed Centre).

Inter situ conservation

An intermediate approach that includes provenance trials, progeny tests, seed orchards and breeding populations, and assisted migration.

Effective population size (Ne)

A number corresponding to the number of breeding individuals in an idealized population. An Ne of at least 1000 is deemed sufficient. A census size of 5000 is used as a conservative guideline.

Gap analysis (Conservation)

A scheme that integrates information from species, BEC zones, and protected areas to determine conservation status

Effects of climate on forests include ___.

d. a and b

Extinct species revival refers to ___.

the revival of some genes from extinct species

What is the climate niche of a plant species?

a. The range of climate conditions within which the plant species can survive and grow.

Which of the following is not true regarding the advantages of climate variables over geographic variables?

c and d

Overlaying a future climate niche onto the current climate niche can delineate the following sections:

d. a, b and c.

What are the two approaches to deal with climate change?

Mitigation and adaptation.

A genecology function developed for a test site reflects ____.

the genetic effect of populations that are from different climates

The general weather of an area over a long period of time is known as the __________.

climate

Which of the following traits is not suitable for short term genecology experiment?

Productivity

The response function of a population reflects ____.

the environmental effect of the test sites

Geographic variable based genecology functions or transfer functions are not able to predict the impact of climate change because ___.

d. a and b

Which of the following is not an objective of genecology?

Determine the differences between two populations

What is the major limitation of general transfer functions?

Low model accuracy.

Which of the following is not true about the forests?

Forests have no problem to adapt to climate change.

A genecology function developed for one environment can be ____ another environment with the same set of populations.

d. b and c

Which of the following is not true about genecology?

To determine the effect of genetic drift.

Which of the following functions represents environmental effects of climate on a tree populations?

a response function

Which of the following is not correct about the effects of climate on forests?

Climate change will not affect the best performance of local trees.

What will be the mostly likely response of tree populations at the leading edge under climate change?

a. migration to new locations