ES 320 Midterm

anthropocene

the current geological age, viewed as the period during which human activity has been the dominant influence on climate and the environment

ordovician-silurian extinction (O-S)

~450 mya, massive glaciation and sea level drop, caused by continental drift, 60-70% of all species gone

late devonian extinction (late D)

~370 mya, 70% of species lost, global anoxia possibly triggered by global cooling or oceanic volcanism

permian-triassic extinction (great dying)

252 mya, 96% of marine speies and 70% of land species lost, severe volanic activity, environmental changes, long-term methane release

triassic-jurassic extinction (T-J)

201.3 mya, 70-75% of land/marine species lost, resulted from volcanic eruptions and greenhouse gas emissions

cretaceous-paleogene extinction

66 mya, 75% of species lost, non-avian dinos vanished, gave rise to mammals, asteroid impact + volcanic activity

living planet index (LPI)

measure of the state of the worlds biological diversity based on population trends of vertebrate species from terrestrial, freshwater, and marine habitats

what are the main risk factors in extinction?

low, fragmented population size

habitat loss

poaching pressure

conservation biology

the development of appropriate scientific principles and the application of those principles to developing technologies for the maintenance of biological diversity to developing technologies for the maintenance of biological diversity

fundamental characteristics of conservation biology

1. it is a crisis discipline where action in conservation must often be taken before all the facts can be assembled

2. it is holistic in the sense that it embraces a wide range of disciplines and theories - IBT, genetics, ecology, metapopulation biology, hazard evolution

3 goals of conservation biology

1. to investigate and describe biodiversity

2. to understand the effects of human activities on species, genetic variation, communities, and ecosystems

3. to develop practical interdisciplinary approaches to protecting/restoring biodiversity

axioms of conservation biology

1. natural communities are th eproducts of coevolutionary processes (eg. keystone species, sea otter)

2. many ecological processes have thresholds below and above which they become discontinuous or chaotic

3. genetic and demographic processes have thresholds below which nonadaptive, random forces begin to prevail over adaptive, deterministic forces within populations

4. nature reserves are inherently in disequilibrium for large, rare organisms

normative postulates of conservation biology

1. diversity of organisms is good. biological diversity has intrinsic value

2. ecological complexity is good (extinction is not good and must be avoided)

3. evolution is good

4. biotic diversity has intrinsic value

the big five

1. habitat degradation/loss

2. overexploitation

3. invasive species

4. climate change

5. nitrogen deposition

also pollution, disease, overuse of freshwater

major threats to nature

1. industrial agriculture

2. human population growth

3. pollution

4. habitat destruction/resource extraction

core discipline in CB

population biology

taxonomy

ecology

genetics

the romantic-transcendental conservation ethic (the preservationists)

thoreau, muir, emerson

nature has other uses than human economic gain

nature as a temple/place to cleanse/refresh

celebrated aesthetic and spiritual value of contact with wild nature

a non-economic view

1st principle: stressed equity - fair distribution of resources → current and future generations - origins of sustainable use concept

resource conservation ethic (the conservationists)

saw only resources in nature

nature = assortment of components that were either useful, useless or noxious to people

economic, reductionist, and selective

2nd principle: efficiency - multiple uses

the evolutionary-ecological land ethic

humans as part of the ecosystem - which is complex, evolves, and provides all of the different values from different viewpoints

“the biota as a whole is useful, and the biota includes not only plants and animals, but soils and waters as well”

first principles from indigenous conservation biology (6 principles for indigenous-led CB)

1. reconciling different worlds

2. respecting first nations law and jurisdictional authority

3. establishing ethical spaces of engagement

4. pulling together - applying diverse indigenous knowledge concepts in ocean and marine governance

5. indigenous knowledge is science

6. evolving co-governance for ongoing reconciliation

take home themes from BC oil tanker debate

1. shift from consultation to consent

2. courts as catalysts (legal victories reshaping national energy policy)

3. indigenous diversity (support for and opposition to tanker bans both exist with indigenous communities)

4. law + governance (indigenous law is central to coastal decision making)

BC oil tanker debate

2019 – Oil Tanker Moratorium Act

• Ban on large oil tankers on BC north/central coast

• Seen as protective floor, not full solution

• Some First Nations opposed → economic self-determination

• Shows Indigenous views are not uniform

2020s–Present

• Ongoing debate about repealing/amending ban

• Coastal Nations assert FPIC + Indigenous laws

• Ban still law, but politically contested

how is it that human population growth rate declines as affluence and child survivorship increases?

the demographic transition

declines in birth rates followed by declines in death rates bring about an era of rapid population growth

women have fewer babies (increase in womens reproductive freedom)

the demographic transition

THE OVERALL PATTERN OF CHANGES IN BIRTH & DEATH RATES AS SOCIETIES BECOME MORE ECONOMICALLY DEVELOPED: (first birth rates high, death rates high; then death rate drops -> pop. skyrockets; but then birth rates also drop (=middle transition), and then birth and death equilibrate at new low level and population stabilizes

the IPAT model of human impact on the environment

impact = population x affluence x technology

Both increases in population and consumption affect impact.
Technology can influence the environmental impact of affluence through more efficient ‘green’ production

the kuznets curve

inequality rises during early industrialization as some benefit more than others, peaks, then falls in more advanced, post-industrial economies with better education, welfare, and service sectors

benefits from changes to ecosystems

1. improvement in health

2. access to information

3. we are all getting wealthier

role of conservation biology

• To illuminate biodiversity patterns, threats, and potential solutions

• Policy decisions about whether to and how to protect biodiversity based on many factors (economics, politics, societal values)

biophilia

the innate human tendency to seek connections with nature and other forms of life, driven by a deeply rooted biological need

why is biodiversity important?

biodiversity is more than just the parts of a living system, such as genes, individuals and species -- biodiversity also includes the ways the various parts interact with each other, including competition, predation and symbiosis

what is a species?

1. interbreed in the wild to produce viable, fertile offspring

2. is morphologically, physiologically, or biochemically distinct from other groups in some important characteristic

3. because of their relatedness, share at least one morphological or molecular trait that is absent in other potentially related groups

biological species definition

“interbreed in the wild to produce viable, fertile offspring” - Mayr

morphological species definition

“is morphologically, physiologically or biochemically distinct from
other groups in some important characteristic” - Cronquist

phylogenetic species concept

“because of their relatedness, share at least one morphological or molecular trait that is absent in other potentially related groups.”

• focuses more on the evolutionary history (relies on genetic data)

• must still consider what type and magnitude of genetic differences exist, and in what
  portions of the genome constitute different species and must employ modern computational tools to manage the increasingly large datasets produced in genetic analyses

limitations to biological species concept

1. asexual reproduction

2. hybridization (different species can interbreed and produce viable offspring

3. different rates of evolution

4. ring species (a series of populations can interbreed with adjacent populations but two geographically distant populations cannot interbreed)

5. geographical barriers

6. behavioural isolation

7. extinct or fossilized species

8. closely related species

is vancouver island marmot a distinct species

YES

Why it’s considered a separate species
•Genetic evidence: Molecular studies show clear genetic divergence from other Marmota species.
•Morphology: It has distinctive features, including darker fur and unique white facial markings.
•Behavior and ecology: Differences in social structure, habitat use, and vocalizations compared to mainland marmots.
•Geographic isolation: Long-term isolation on Vancouver Island following glaciation likely drove speciation.

van isl marmot

Conceptual survivorship curves for marmots

Vancouver Island marmots → Type I–leaning pattern typical of long-lived mammals

hoary marmots → experience more constant mortality across life stages (Type 2)

key evolutionary takeaway from van isl marmots

• example of island-driven speciation

• a hoary-marmot-like ancestor colonized van isl

• post-glacial isolation prevented gene flow

• genetic, morphological, and behavioural differences accumulated

• results in a distinct species not a subspecies

how many species are there?

Estimates of total # range up to 100 million species, but most accepted range is 3-30
million

in terrestrial communities, diversity increases with:

1. decreasing elevation

2. increasing solar radiation

3. increasing precipitation

species richness increases where:

complex topography and great geological age produce more environmental variation

latitudinal diversity gradients

The gradient involves high species' numbers near the equator (at low latitudes) and lower numbers of species at high latitudes.

energy: evapotranspiration → ____ → ____ → ____ → ____ → ____

productivity, more energy, more biomass, more individuals, more specialization

area: ____ → ____ → ____

bigger ranges, larger pop. sizes, lower extinction rates

species-energy relationship

suggests the amount of available energy sets limits to the species richness of the system

increased solar energy (with lots of water) at low latitudes causes increased net primary productivity (or photosynthesis)

species-area relationship

the relationship between the area of a habitat and the number of species found within that area

what determines patterns of species diversity?

1. species-area hypothesis

2. species-climate stability hypothesis

3. species-climate harshness hypothesis

4. species-energy hypothesis

species-climate stability hypothesis

tropics have a more stable climate

species-climate harshness hypothesis

few species can tolerate cold (they would need specialized behaviours to survive)

species-energy hypothesis

tropics have greater productivity

alpha diversity

the species we find in one place (ie. saanich peninsula)

gamma diversity

species we find in an entire region (ie. species on van isl)

beta diversity

gamma/alpha

connects alpha and gamma

describes the rate at which species composition changes across a region

Each letter represents a different species; some species have populations on only one peak, while others are found on two or more peaks.

The variation in species richness on each peak results in different alpha, gamma, and beta diversity values for each ecoregion. This variation has implications for how we divide limited resources to maximise protection.

biome

large area characterized by its vegetation, soil, climate, and wildlife

large marine ecosystems

regions of ocean space encompassing coastal areas from river basins and estuaries to the seaward boundaries of continental shelves and the outer margins of the major current systems.

characterized by distinct: (1) bathymetry, (2) hydrography, (3) productivity, and (4) trophically dependent populations

5 of the most diverse systems on earth

1. tropical forests

2. coral reefs

3. deep sea

4. large tropical lakes and river

5. mediterranean climates

free resources + no regulations = ______

tragedy of the commons

tragedy of the commons

if many people enjoy unfettered access to a finite, valuable resource, such as clean water/air, they will tend to overuse it and may end up destroying its value altogether

how increased oil tanker traffic raises risk

1. higher oil spill risk

2. oil contamination directly harms alcids

3. population-level vulnerability

4. overlap with important foraging migration are

GDP

measures economic activity without accounting for costs of non- sustainable activities (e.g., overfishing, strip mining) → increases through activities that are destructive to long-term economic well-being

direct use value

products harvested from the wild by people

eg. timber, seafood, medicinal plants

use value

direct and indirect value provided by some aspect of biodiversity

option value

determined by the prospect for future possible benefits for human society

eg. new medicines, future food sources, genetic resources

intrinsic value

accords a value to biodiversity independent of its value to humans

indirect value

benefits provided by biodiversity that do not involve harvesting or destroying the resource

provisioning services (direct use values)

seafood

timber and fiber

pharmaceutical compounds

regulating services (indirect use values)

water quality control and disease

climate regulation

cultural services

tourism and recreation

esthetic and spiritual

supporting services

nursery habitat

habitat or supporting services (eg. existence value) = ______

biogeochemical and ecological processes necessary for the production of all the other ecosystem services

ecosystem services

• diversity/productivity

• carbon offset programs

• water and soil protection

• waste treatment and nutrient retention

• climate regulation

• species relationships

fishing down the food web

fishing pressure progressively removes species at the top of the food web first, then shifts toward smaller, lower–trophic-level species over time

Core idea

• Early fisheries target large, long-lived, high-trophic predators (e.g., cod,
  tuna, sharks).

• As these species decline or collapse, fisheries switch to smaller, faster-
  growing species (e.g., herring, sardines, squid, invertebrates).

• The mean trophic level of the catch declines through time, even if total
  catch stays high

objective, key finding, interpretation, ecological implications

Objective: Quantified changes in the mean trophic level of global marine fisheries landings from 1950 to 1994 using FAO catch data and trophic level estimates.

Key finding: mean trophic level of the catch declined over time, reflecting a shift from harvesting larger, high-trophic predators (e.g., cod, swordfish) to smaller, lower-trophic species (e.g., forage fish, invertebrates).

Interpretation: indicated that fisheries were progressively removing species from higher to lower trophic levels (fishing down marine food webs)

Ecological implications: evidence of unsustainable exploitation patterns that restructure food webs and potentially a reduction in ecosystem resilience

mean trophic level (MTL)

average trophic level of species in global fisheries landings

higher values mean more top predators being caught

lower values mean more lower-trophic species like small pelagics and invertebrates

why does MTL matter?

1. ecosystem restructuring

2. reduced resilience

3. masked overfishing

4. shift to invertebrate fisheries

trophic cascade

ecological concept of side effects when the trophic level of the ecosystem is reduced or removed

fishing down the food web takeaway:

“fisheries can appear successful while progressively removing higher trophic levels from marine food webs”

T/F total landings can remain economically valuable even as trophic level declines

true

list 6 concerns that come from the oceans being saturated with carbon, leading to warmer, less oxygenated, more acidic oceans:

1. bleaching

2. rising sea levels

3. toxic algae

4. habitat degradation

5. acidification

6. fisheries

environmentalism is characterized by ______ and ______ activism, whereas conservation biology is a ___________ whose findings contribute to ______

political, educational

scientific discipline, the environmental movement

the species energy hypothesis suggests:

the amount of available energy set limits to the species richness of the system

what are the main negative externalities in BC associated with climate change and the following:

forestry:

agriculture:

urban expansion:

forestry: fires

agriculture: floods

urban expansion: floods and fires

lifeboat ethics

proposed by hardin

since global resources are finite, hardin believed the rich should throw poor people overboard to keep their boat above water

precautionary principle

if an action or policy has a suspected risk of causing severe/irreversible harm to the public or the environment, protective measures should be taken even without full scientific certainty

It prioritizes preventing damage over fixing it later