Conbio Asynchronous Lecture Extinction + Invasives

• humans have sped up extinction

  by 1000x times
• extinction


  The extinction rate today is significantly higher than the expected natural rate (i.e.,"background" rate). This rapid pace does not allow enough time for ecosystem to recover or other species to occupy vacant niches
• extirpation


  the local or regional disappearance of a species from only a part of its range. Includes loss of populations
• sixth mass extinction


  current mass extinction caused primarily by habitat loss due to human actions

  "the anthropocene"
• Mass extinctions are often followed by a burst of evolutionary diversification of remaining species


  possibly because the surviving species started using habitats and resources that were previously 'occupied' by more competitively successful species that went extinct.
• endemic


  (adj.) native or confined to a particular region or people; characteristic of or prevalent in a field
• island biogeography theory


  species on an island are a function of the mainland

  used to predict species richness on islands

  
  

  a field within biogeography that examines the factors that affect the species richness of isolated natural communities. The theory was developed to explain species richness of actual islands. It has since been extended to mountains surrounded by deserts, lakes surrounded by dry land, fragmented forest[1] and even natural habitats surrounded by human-altered landscapes. Now it is used in reference to any ecosystem surrounded by unlike ecosystems

  
  

  • Distance from mainland

  • Size of island (target size)

  • Immigration and Extinction

  • Species- area relationship

  
• species-area relationship


  The number of species on an island can be predicted from the area (size) of an island

  
• island biogeography describes what?

  the relationship between the rates of colonization and extinction on islands
• emerging infectious diseases

  infectious diseases that are new to humans or that have recently increased significantly in incidence, in some cases by spreading to new ranges
• IUCN categories of conservation status from worst to ok

  EX extinct

  EW extinct in wild

  CR critically endangered

  EN endangered

  VU vulnerable

  NT near threatened

  LC least concern
• The percentage of species evaluated for major taxonomic groups using the IUCN Red List categories

  
• the living planet index

  Measures how well >2600 species of mammals, birds, fish, reptiles and amphibians are doing according to the Red List

  
  

  Increased 31% for temperate species and decreased 61% for tropical species from 1970 to 2008

  
• endangered species act of 1973


  A law requiring the federal government to protect all species listed as endangered.

  maintain official list of threatened species

  forbids projects that would compromise endangered species
• assisted colonization


  Species at risk of extinction are moved to areas where they have not been found before.
• managed relocation


  Process of moving members of a

  species from its known range to a

  habitat where it is more likely to

  survive.
• assisted migration/managed relocation


  •An intervention technique aimed at reducing negative effects of climate change on populations, species, or ecosystems.

  
  

  •The intentional movement of biological units from current areas of occupancy to locations where the probability of future persistence is predicted to be higher.

  
  

  •The goal is to reduce the threat of diminished ecosystem services or extinction from climate change.
• dilemma of assisted migration

  1. It is morally wrong for humans to cause a species to go extinct.

  2. It is morally wrong for humans to introduce a non-native species into an area.

  3. Human-induced climate change will cause species to go extinct unless we relocate those species to areas outside their native range.

  4. Therefore, we are either causing species to go extinct orw e are creating exotic species; regardless, we are doing something morally wrong
• values at stake with assisted migration

  ecosystem health, biodiversity, anthropocentric values, intrinsic value
• intrinsic value


  Value of an organism, species, ecosystem, or the earth's biodiversity based on its existence, regardless of whether it has any usefulness to us.
• biological invasions


  The successful establishment of a species in a region not previously occupied followed by rapid range expansion
• introduced species


  is the result of direct or indirect, deliberate or accidental introduction of the species by humans.
• invasive species


  an introduced species that causes harm to the environment, the economy or to human health.
• how does climate change interact with introduced species?

  invasive species benefit from climate change

  
  

  there are data gaps and data is context dependent so it is hard to tell if a species is increasing range or invading
• 10's rule of invasion ecology

  10% of introduced species case ecological/economic impacts
• Given global climate change, is more harm caused by allowing species to go extinct or creating possible invasives through managed relocation?

  we can use models to predict if species will negatively affect ecosystem
• pros of managed relocation

  aims to save species from climate change by purposefully transporting them to areas where they have not previously occurred, but where they are expected to survive as temperatures increase.
• cons of managed relocation


  Accurate risk assessment is impeded by contingency:the impacts of introduced species vary over time and space under the influence of local environmental variables, interspecific interactions, and evolutionary change
• hoegh-guldberg 2008 et al. 2008 science
• novel ecosystems


  Ecosystems completely new to Earth that are a result of human activity, urbanization, and industrialization.

  
• two types of biotic change

  - Slow, insidious change resulting from chronic low-intensity climate drivers

  - Rapid transformation (tipping points, thresholds) due to short-term, high intensity events (hurricanes, bomb, etc)
• main idea behind novel ecosystems

  Many ecosystems are rapidly being transformed into new, non historical configurations owing to a variety of local and global changes.

  • Biotic changes(extinctions and invasions)

  • Abiotic changes (land conversion, climate change)

  
• historical ecosystem

  retains species and ecosystem properties prevalent in the past
• hybrid ecosystem


  Retains characteristics of historic system but composition or function now outside the historical range of variability

  
• novel ecosystem


  species composition and/or function completely transformed from historic system and may be entirely composed of species not native to that geographic location or that might exhibit different functional properties

  
• How can a native species that

  evolved with this ecosystem

  cause this damage?

  ex. prairie dogs causing dust storms and soil issues


  • Urbanization and habitat fragmentation

  • Climate Change - Winters have become significantly wetter - 34% increase in precipitation over last 30 years

  • Growing season extended - increase of 2.5 oF• Atmospheric N deposition favors N loving plants

  • Increased CO 2 concentrations favors C3 plants over C4 plants

  • Fire suppression increases plant available N which in turn affects phenology and competition

  • Wind erosion

  
  

  • Introduction of cheat grass, Bromus tectorum, an invasive grass, favored by warmer and wetter winters and eaten by prairie dogs. They now graze instead of hibernating in winter!
• indigenous species


  species that originate and live in an area or environment.
• non-native species


  Species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans.

  don't need human help to be sustained
• immigrant vs introduced

  non-indigenous species arriving in a given location without deliberate human help

  vs introduced by humans
• The 3 Ts of introducing invasive species

  Trade - Travel - Transport

  (terrorism??)