Lecture 10: Intro to Climate Change Vulnerability – Lecture Outline (Part 1)

Climate vulnerability assessments focused primarily on the magnitude of anticipated climate change

• Referred to as the ‘climate exposure’ of the species

• Often, assessments are correlative models

• Models are built on associations between known species occurrence with existing climate or habitat variables to predict species distribution across geographic spaces

• Then, a climate projection is used to infer climate exposure based on predicted changes in habitat suitability

What does ‘climate exposure’ of the species ask?

how exposed is a species?

Often, assessments are correlative models:

ecological niche or bioclimatic envelope models

Models are built on associations between known species occurrence with existing climate or habitat variables to predict?

species distribution across geographic spaces

how species are distributed

A climate projection is used to infer climate exposure based on predicted changes in habitat suitability

how much exposure bighorn sheep have in response to climate

What do models/projection of future conditions assume?

a scenario of climate change; also assumes no adaptations to changing conditions

What numerous issues are focused on in the model?

(1) Assessments that focus (‘climate exposure’) often overlook other components that could affect vulnerability

(2) Climate vulnerability assessments are typically conducted at the species level... But climate vulnerability can vary considerably among populations

Assessments that focus (‘climate exposure’) often overlook other components that could affect vulnerability

• adaptive capacity

• phenotypic plasticity

• habitat connectivity

What is adaptive capacity?

the potential to persist in situ or shift ranges

What is habitat connectivity?

how connected a population is to another area that they could move to

What is phenotypic plasticity?

the ability of individuals of a given genotype to modify their phenotype in response to environmental conditions

Climate vulnerability assessments are typically conducted at the species level... But climate vulnerability can vary considerably among populations

differences in population in different areas

in broadly distributed species, various populations will likely be affected (potentially extirpated) before species goes extinct

Population level

climate change will affect populations at the species level

Mitigating the impact of potential climate shifts:

• Management decisions that most directly influence species are often made at the population level

• Natural resource managers must determine how to allocate agency resources within jurisdictions

• Conservation efforts to mitigate the effects of climate change would benefit from information on vulnerability at the population level

Management decisions that most directly influence species are often made at?

the population level

What must natural resource managers determine?

how to allocate agency resources within jurisdictions

• often times don’t encompass entire areas

What would conservation efforts to mitigate the effects of climate change benefit from?

information on vulnerability at the population level

What are Desert bighorn sheep distribution and dispersal are affected by?

topography

distance

barriers

Study Areas and Conditions for Desert Bighorn Sheep Distribution:

• 62 Populations, 1652 individual sheep

• NPS (10 parks) and adjacent BLM, USFS, and Indian Reservations

• Habitat connectivity: more discrete (Mojave Desert) to more continuous (Colorado Plateau)

• Influence of barriers

• Differing climates: Mojave, Sonoran, and Colorado Platea

• Differing elevations

• Predominantly native populations in California, Arizona, and Nevada

  • Mainly reintroduced in Utah

Population-level Factors

• Genetic diversity

• Isolation

• Maximum Elevation

Genetic diversity:

Fitness: positive correlation with population fitness in many species

Persistence in many species: positive correlation

Isolation:

Genetic diversity: negative association

Ability to track climate: negative association

Maximum Elevation: Index of current climate stress

Precipitation: positive correlation

Persistence of desert bighorn sheep in Mojave: positive association