Conservation Bio (465)

5 main drivers of biodiversity loss

• Habitat loss & degradation

• Exploitation

• Climate change

• Pollution

• Invasive non-native species

Anthromes (+ types and % coverage)

Biome made by humans:
living
- Dense settlements
- Villages
agriculture
- Croplands
- Rangelands
recreation
- seminatural

Covers 75% of earth’s ice-free land surface
Rest is wildlands

Distribution of biomass (10,000yrs ago vs today)

Before: 99% wild, 1% human
Now: 1% wild, 67% livestock, 32% human

List the scales of biodiversity

• Gene

• Individual

• Population

• Community

• Ecosystem

• (Region)

• Biome

• Biosphere

3 measures of biodiversity

• Changing variation

• Abundance and rarity

• Composition

3 types
Genetic diversity - variet of genes within species
Species diversity - variety and abundance of species
Ecosystem diversity - variety of habitats, communities, and ecological processes in an ecosystem

Define biodiversity

variability among living organisms and the ecological complexes they belong to

includes diversity within species, between species, and across ecosystems

Which type of species most at risk of extinction? (in terms of the proportion of that species type facing extinction, according to IUCN Red List)

Amphibians (40%)

How many species threatened with extinciton by end of century

1 million

Describe the geographic distribution of biodiversity loss

• Biodiversity hotspots and grasslands are most at risk

• Midnorthern latitudes (central asia, USA) and southern latitudes have greatest loss (south africa, australia, argentina, brazil)

• 71% of human population live in grasslands and biodiv hotspots
  
  Hotspot = high biodiv and high loss

Caused by climate change and human footprint

Species richness vs abundance vs turnover

Richness = pure # of types of species
Abundance = # of species individuals
Turnover = change in species composition, includes which species are lost and which are gained

Counterfactual

hypothetical scenario of what would have happened without intervention. used to determine effectiveness of conservation actions

Measurement of conservation action results: Describe…
- Absolute positive impact
- Relative positive “
- Relative negative “
- Absolute negative “

Abs + = counterfactual was bad (biodiv loss), with intervention it’s now good (biodiv gain)
Rel + = counterfactual was bad, intervention is less bad (but not good)

Rel - = intervention did worse than counterfactual (though both were good)
Abs - = intervention did worse than counterfactual, in that counterfactual showed biodiv gain and intervention caused biodiv loss. you fucked up real bad.

Effectiveness of conservation action

66% of cases were absolute positive or relative positive. This means that action slowed biodiversity decline or improved biodiversity.

many ways for conservation to be done wrong

Soule’s normative postulates

• Diversity of organisms is good

• Ecological complexity is good

• Evolution is good

• Biotic diversity has intrinsic value

Soule’s functional postulates

• Evolutionary postulate

  • species are interconnected through coevolution

• Ecological scale

  • Ecosystems need to be large enough to function properly

• Population scale

  • Small populations are vulnerable to random events and genetic problems

• Disequilibrium in reserves

  • Nature reserves are not self-sustaining and require active management

Evolution of the focus/framing of conservation over time

1960-70s

• Nature for itself

• species, wilderness, protected areas

1980-90s

• Nature despite people

• extinction, threats

2000s

• Nature for people

• ecosystems, services & values

2010s

• Nature and people

• environmental change, resilience, adaptability + socioecological systems

CBD

• Conservation of biological diversity

• Sustainable use of components

• Fair and equitable sharing of benefits from (genetic) biodiversity

What makes an intervention legitimate

Biological effectiveness

Social legitimacy and procedural fairness

Respect for rights & knowledge systems

Cost-effectiveness and durability

Monitoring, accountability, and reversability

Non-native species (definition)

species that has been introduced outside its native historical range

how do humans facilitate invasion

• transportation

  • across vast distances

  • across physical boundaries

  • via plane, train, motorvehicle, boat, etc

    • may stick onto people’s clothing or be transported in their food

• removal of physical barriers

  • man-made canals

• climate change → range expansion

Biological invasion

Defined as a process and an event
= the spread & establishment of a species into a region beyond its natural range

invasive species

species undergoing a population outbreak that causes adverse ecological or economic effects
- could be native or not
- same species could be invasive in one area but not be invasive in another area
OR

A non-native species that spreads rapidly

Difference between natural and human-assisted invasions

Natural
- low frequency of long-distance dispersals and invasion b/w biogeographic realms
- low # of species transported per event
- small variation in mechanisms & routes of dispersal
- low potential for synergies with other stressors

Human - opposite of all above
- synergies with plastic pollution, climate change, etc.

Impacts of invasions (at each level)

Alpha, beta, and gamma diversity

Alpha - one site or community
Beta - regional (turnover between communities)
Gamma - whole landscape (larger region)

Relationship between Species richness, Area, and Connectivity/Isolation

**note: isolation actually increases B

SAR formula (+ where do you find beta and gamma in this relationship)

S = cA^z
c is the habitat-specific constant
z is the slope

z = beta on log-log scale

Asymptote is gamma diversity
gamma = alpha * beta

z predicts proportion of species remaining after a decrease in area

S2/S1 = (A2/A1)^z

Criteria for hotspots

• >1500 endemic species

• >70% already lost

ignores functional and phylogenetic diversity

Biological scales of change - what kinds of changes occur at sub-pop, pop, species, and ecosystem levels?

sub-pop → altered foraging, timing, avoidance
pop → local extirpations
species → risk of extinction with range-wide decline
ecosystem → trophic cascades, altered flow of biomass & energy, lost ecosystem services

Indicators of change

Genetic (loss of genetic div)
Abundance (losing numbers in pop)
Land use (contracting range)
Occurence (extirpations and extinction)
Loss of ecosystem services
Status

Definition of mass extinction

Loss of 75% of species

1000 known extinctions have occurred in the last couple centuries. Under normal rates, how long would it take for this number of species extinctions to occur?

800-10,000 years

Quaternary megafauna extinction

Occurred 5k-10k years ago
Matches time and place that humans spread across continents
Megafauna that had coevolved with humans were less impacted
Debate: overkill vs climate change

Northern Biodiversity Paradox

Species richness could actually go up in northern regions as ranges shift with climate change

Extinction debt

Global vs local patterns of biodiversity change

Global - clear decline
Local - some decline, some gain, balances out

Ecosystem homogenization

Global trend

Beta diversity declining
- means that communities becoming more similar

What kind of ecosystem (marine, freshwater, terrestrial) has highest relative species richness

Freshwater ecosystems

North america has large proportion of global freshwater diversity
Freshwater species have higher extinction rate than other species in NA

Formula to calculate extinction rates

r = 1 - p^(1/n)

p = proportion of species that survive during the time period
n = time period in decades

r is # extinctions per decade

Background extinction rate for freshwater fish and bivalves (+ explain calculations)

Fish: 0.33 E/MSY
1 extinction per 3 million species per year

Bivalves: 0.05 E/MSY

See how many years typically last in fossil record, F
1/F = extinction rate in E/MSY

Causes of freshwater fish extinctions in North America (ranking)

1. Physical habitat alteration

2. Invasions

3. Pollution & Hybridization (tied)

   1. pollution includes calcium, chloride (salts), plastics, nitrogen, etc.

4. Overharvesting

What % of annual river runoff are regulated

Env impacts of damn

Upstream

• Flooding, flowing → stillwater

• Habitat shifts: less oxygen, more turbidity, more sedimentation + stratification

Downstream

• Altered flow regime

• Siltation (affects fish nesting)

• Scours the bed below the damn

• Colder water ?

At dam

• Block fish migration

• Fish injured and killed

Approaches to protect freshwater fauna (and their problems)

• Legal protection

  • too slow

  • does not reverse any damages

• Hotspot identification & protection

  • not all endangered species occur in hotspots

• Relocation

  • unexpected effects

  • difficulty identifying suitable habitat

  • refugia are not necessarily permanent

Species extinction rates and Population extinction rates (relative to historical background)

Species: 100-1000x higher than background
Population: 10-100x higher than background

Note: species extinctions have increased more than population extirpations
This is bc current drivers of loss are more large-scale. Low connectivity means extirpated populations are not recolonized as much - more species loss.

The two population paradigms

• Larger populations have lower risk of extinction

  • smaller pops more vulnerable to random factors. larger pops would need persistent high mortality from persistent stressor

• Higher environmental variability shortens the time to extinction

Note: population decline may be delayed response to environmental change. may decline after the stress accumulates

What is a PVA and what can you use it for

PVA cycle

Why stage-structured > age-structured

• Hard to tell age of an animal/plant

• Survival more dependent on size than age, and growth may vary

• Focuses attention on critical transitions → important for management

How do we estimate key parameters for a PVA?

• Clutch size (# eggs in a nest)

• Cluthes per season (# nests per female)

• Hatching & emergence success

• Remigration interval (time between female nesting seasons)

Calculate time to extinction from Nt = No (1-r)^t

Set Nt = 1, solve for t using log

NCP types (according to IPBES)

Material

• Food

• Materials

• Energy

• Medicinal or genetic resources

Regulating

• Habitat creation and maintenance

• Pollination and seed dispersal

• Air quality regulation

• Climate regulation

• Water quantity and quality regulation

• Ocean acidification regulation

• Soil creation

• Hazards regulation

• Regulation of detrimental organisms

Social/non-material

• Learning and inspiration

• Physical and psychological experiences

• Supporting identities

Other

• Maintenance of options (across all)

Drivers of marine extinctions

High mobility taxa - direct exploitation

Low mobility taxa - pollution, climate change, and habitat

Regions most impacted: Temperate North Atlantic (Around Europe and USA east coast) + Central Indo-European (large area around indonesia)

Exploitation cascade and feedback

Exploitation pressure → direct removal → population effects → community effects → ecosystem effects → government response

Markets, tech, and demand cause cause exploitation pressures to increase even as scarcity rises. Product becomes more rare, high price, drives more exploitation or we develop better tech to trap scarce resources more efficiently → cycles.

State of resource from sustainable to extinction

Sustainable

• pop can persist, harvest < replacement

Overharvest

• pop decline, harvest > replacement

Depensation, Allee effect

• as resource becomes more rare, decline becomes more rapid
  > market allee: rarity makes more valuable → more exploitation
  > or bc threshold for population growth, inability to sustain in small numbers

• low density makes recovery much harder

Commercial extinction

• no longer profitable to harvest

Biological extinction

• gone, permanently

Harvest selectivity

We target the

• largest

• most valuable

• most visible

• dense

• adults (reproductive stage)

• top predators

Selective harvest changes selection pressures

Logistic growth model & max sustainable yield

dN/dt = rN(1 - N/K) - H

Growth rate is highest at half capacity (where N = K/2)
This is the max sustianable yield
Often harvest just below this rate to account for error, variability, uncertainty, ecosystem context

Assumptions of logistic growth model

• No migration

• Constant r and K

• Ignores age/stage structure

• Ignores spatial distribution

• Ignores environmental variability and uncertainty

• Ignores species interactions

Exploitation rate

proportion of total biomass that is harvested each year

Conservation implication of ecological-social models

• conservation must monitor beyond the target species

• food security and biodiversity are coupled

• leakages are a central outcome, not a side effect

• sustainable use depends on substitutes

• management should be portfolio-based (combining multiple interventions)
  
  The goal is not simply to reduce one pressure locally, but to

  prevent harmful displacement while supporting recovery, food security,

  and legitimate governance across the linked system

What is CITES, and its critiques?

convention on international trade of endangered species

• protects unsustainable trade of endangered species

• taxonomically biased

• only international trade, not domestic

• parts can be traded if collected before CITES (1975)

• only $6 million budget to fight $320 billion dollar industry

Indicator framework (what would you use as indicators for pressure on resource, state, demography, function, governance, and equity)

Pressure

• rate of harvest, bycatch, poaching

• fishing effort

• logging intensity

State

• abundance

• biomass

• occupancy

• density

• species richness

• genetic diversity

Demography (to tell if growth rates are recovering)

• survival, recruitment, fecundity, age/size structure, sex ratio

Function

• seed dispersal, predation, herbivory, deadwood decomposition, trophic structure

Governance (to tell if rules are legitimate)

• compliance, enforcement probability, tenure security, benefit sharing

Equity

• food security, income, cultural use, conflict, local participation

8 criteria for sustainable exploitation

• Biological capacity for replacement

• Population structure preserved (not selectively harvesting)

• Ecosystem function preserved

• Evidence-based adaptive management

• Improve selectivity of exploitation - minimize bycatch and other non-target effects

• Effective governance, clear rights

• Economically viable, aligned incentives

• Considers social & cultural context

Linked Outcomes Conservation Model

• Manage ecological recovery

• Regulate markets and trade

• Support livelihoods and food security

• Manage substitute resources

• Monitor linked outcomes

How does exploitation act as a demographic and evolutionary force? How is it selective?

functional traits influence…

ecosystem properties
species response to env change

Complementarity vs selection effects

Complementarity - increased functioning bc species work together by partitioning resources or facilitating each other

• Polycultures would perform better than monoculture - called Transgressive overyielding

• This was found during Cedar Creek crop experiment

Selection - increased functioning bc more species = higher chance of a productive, high-performing species

• No polyculture would be better than highest performing monoculture
  
  

BEF Relationship changes over time

• Initially, selection has greater impact

• Later as symbiotic relationships develop and coevolve, complementarity takes greater effect

Why ranges shift

• Physiological limits

• Water balance

• Season length

• Biotic interactions

• Disturbance

• Dispersal and demography

Evidence of range shifts in Canada

• Arctic greening and borealization

• Food web re-wiring

• Hybridization

• Southern generalists appearing in north

• Insect outbreaks

• Pressure from deciduous trees in boreal forests

Types of assisted migration

• Assisted gene flow

• Range expansion

• Long-distance translocation

•