LEC.145 Biodiversity and Conservation Flashcards
Which is the most diverse group of land plants?
Flowering plants (angiosperms)
What is the gradient of species richness?
Latitudinal from tropics to poles (except for some species e.g. seabirds most abundant/diverse in high latitudes)
What are the 4 hypotheses for there being more diversity at the tropics?
- Geographic area (shape of planet means more area at tropics)
- Energy-species (availability of resources + climate dictates no. co-existing species in given area)
- Rapoport’s Rule (geographic range of species decreases from poles-tropics)
- Evolutionary speed (tropics have had long time stability + faster rates of evolution)
What are 3 explanations for Rapoport’s Rule?
- Climatic variability greater at high latitudes so broad niche required to survive
- Glaciation (species with high dispersal ability repopulate north so have large geographic range)
- Competition between species (tropics have more competition so restricted habitat and small niches)
What are 4 ways of measuring biodiversity?
- Species richness (alpha diversity)
- Species composition (beta diversity)
- Phylogenetic diversity (higher diversity when species in community are less genetically related)
- Functional diversity
Define endemism
Species richness of rare species
Why are biodiversity measurements important?
Provide tools for selecting areas to prioritise for conservation
Define a biodiversity hotspot
Geographical area that ranks particularly high in species richness (also based on levels of endemism)
What is a complementarity approach?
Conserving as much biodiversity as possible in a limited area of land available for conservation
What is positively related to species richness and provides ecosystem services that are useful to humans?
Ecosystem functions
Define competitive exclusion
When most competitive species drives others to extinction
What are the 2 types of theories on regulation of local diversity?
- Equilibrium theories
- Non-equilibrium theories
What do non-equilibrium theories on the regulation of local diversity suggest?
That community diversity is due to processes that prevent equilibrium being reached i.e. interfere with competitive exclusion
What do equilibrium theories on the regulation of local diversity suggest?
That community diversity is regulated by processes of competition + evolution to attain a steady + stable state
What are the 3 equilibrium theories?
- Niche concept (specialisation enables more species to co-exist in a given area)
- Heterogenity (more diverse habitats have more niches e.g. vertical structure of trees)
- Island biogeography theory (species diversity = island area + isolation (balance between forces of immigration + extinction))
How does the species-area relationship influence extinction?
Forces of extinction decrease with size (higher resource abundance + habitat heterogenity)
How does isolation influence immigration?
Forces of immigration increase on near islands (speciation is more important on remote islands)
What are the 2 non-equilibrium theories?
- Diversity-productivity relationship (species richness unimodally related to productivity, peak diversity at intermediate productivity)
- Intermediate disturbance hypothesis (low disturbance = competitive exclusion, intermediate disturbance = max diversity due to prevention of competitive exclusion, high disturbance = low diversity as few species survive)
What is the dynamic equilibrium model?
Highest diversity under conditions where neither disturbance nor competitive exclusion dominate
What are the 2 types of succession?
- Primary (from sterile beginnings, non-living e.g. volcanoes, glaciers)
- Secondary (on previously colonised land after major disturbance e.g. landslides, fire)
What are the 2 types of succession process?
- Autogenic (species change due to interactions between organisms themselves e.g. competition)
- Allogenic (species change due to external, non-biological factors e.g. climate change)
Describe the traits of early successional species (colonisers, “r-selected”)
Small, fast-growing, produce many seeds, often no dormancy required (germinate if conditions are favourable), often N fixers e.g. lichens, cyanobacteria, allocate more energy to reproduction than biomass
Describe the traits of late successional species (competitors, “K-selected”)
Large, slow-growing, dormancy, large seeds, competitive (canopy species), allocate more energy to biomass than reproduction
Define seres
Successional stages with characteristic vegetation types + associated biota
What are the 2 types of species replacement models?
- Inhibition model (early arrivals competitively inhibit (e.g. light competition), spread rapidly, + monopolise resources
- Facilitation model (succession = series of sequential invasions, each dependant on site amelioration by earlier colonist, species die out since changes in env. are better suited for later colonists)
Which type of species replacement model is more important when conditions are severe?
Facilitation model
When was the International Union for Conservation of Nature established?
1948
Who introduced the concept of conservation biology in 1968?
Dashmann
What are the 4 types of value of species/habitats?
- Instrumental
- Ecological
- Intrinsic (non-use)
- Uniqueness
What are 4 examples of intrinsic species/habitat values?
- Cultural
- Ecosystem services e.g. pollination
- Recreational
- Transformational
What are 3 examples of instrumental species/habitat values?
- Food
- Medicine
- Ecotourism
Describe ecological species value
Species diversity increases an ecosystem’s stability/resilience, in particular its ability to adapt + respond to changing environmental conditions
Describe uniqueness species value
Sites with distinct species composition have high contribution to beta diversity + help prevent biotic homogenisation
Which species values generally have more moral consideration?
Intrinsic + instrumental
What are 3 disadvantages of species-based conservation?
- In conflict with Indigenous people
- Take priority over others
- Become extinct if we fail
What are the 7 drivers of biodiversity loss?
- Habitat loss + fragmentation
- Over-exploitation
- Invasive species
- Pollution
- Global climate change
- Underlying drivers e.g. agricultural expansion
- Synergistic effects of different factors
What are 3 types of pollution (toxic or non-toxic) that drive biodiversity loss?
- DDT insecticide (long-lasting, easily spread, has declined British raptor pop. since 1950s as DDT thins egg shells)
- Non-toxic plastic microbeads directly consumed by many species
- Non-toxic light pollution that affects behaviour of nocturnal animals
How does climate change drive biodiversity loss?
Species differ in thermal optimum and range of temps. they can tolerate so selective disadvantage when temps. increase
What 2 things can species change as a response to climate change?
- Phenology (migration patterns, reproductive events)
- Distribution (expansions polewards + uphill)
Which 3 types of species are less likely to be able to adapt/respond to climate change?
- Polar/high elevation species (already at max thermal tolerance + nowhere to go if habitats become warmer)
- Tropical mountain species (narrow thermal tolerance + can’t emigrate from where they are)
- Species with low mobility e.g. coral reefs
What are synergistic effects and give an example of how they drive biodiversity loss?
When impact of two factors together is greater than the sum of individual effects e.g. Duke of Burgundy butterfly - if climate improved, still can’t respond to climate change because habitat isn’t available (plants aren’t as thermal tolerant as the butterflies)
What does the Extinct in the Wild category mean in the IUCN’s Red List?
When a species is known only to survive in captivity or as a naturalised pop. well outside the past range
What are 3 pros of species-based conservation?
- Species are more discrete entities than ecosystems
- Convenient for monitoring
- Public interest in species
What are 3 cons of species-based conservation?
- Little known about most species
- Taxonomic bias (vertebrates + trees)
- Species can’t exist without their habitat
What are 7 criteria for selecting areas for conservation?
- Size of area
- Intactness (fragmentation)
- Site condition (disturbance)
- Habitat rarity (e.g. Paramos)
- Level of threat (“crisis ecoregions”)
- Fragility/vulnerability to future climate change (e.g. Gran Sabana ecosystem highly vulnerable to disturbance - soil compaction)
- Biodiversity (richness/endemicity/threat hotspots, complementarity areas)
How many terrestrial hotspots of biodiversity (areas that have exceptional concentrations of endemicity + threat) are there globally?
25
Define complementarity areas
Represent as much biodiversity as possible in a limited area of land available for conservation
What is a challenge of complementarity areas?
Hotspots of richness, threat, + endemicity differ to each other
Define ex-situ conservation
Removal of species from their natural habitat into captivity for their long term conservation, such as to breed for reintroduction or to maintain a genetic stock (can also be private “hobbyist” collection or commercial breeding)
Define in-situ conservation
Actions taken to preserve a species in its natural habitat
What are 3 examples of ex-situ conservation?
- Botanic gardens
- Seed banks (domestic + wild plants)
- Preservation of plant tissue (cryopreserved)
What are 3 examples of in-situ conservation?
- Zoos
- Aquariums
- Wildlife parks
What are the 7 aims of ex-situ conservation?
- Insurance against extinction
- Reservoirs for reintroduction
- Stock for breeding new varieties
- Research (animal behaviour)
- Education
- Fundraising for in-situ conservation (most zoos support this)
- Recreation
What 5 things do reservoirs for reintroduction require (ex-situ conservation)?
- Genetic diversity
- Assisted reproductive tech.
- Eliminated genetic defects
- Controlled spread of disease
- A release strategy
What 5 negative things can captive breeding cause?
- Loss of hunting ability
- Predator blindness
- Locomotion deficits
- Loss of natural social behaviour
- Imprinting
What are 4 contemporary debates on ex-situ conservation?
- Taxonomic bias (many threatened species overlooked)
- Are zoos education or entertainment?
- Expensive + distracts from in-situ conservation
- For profit conservation
What are 2 reasons why biodiversity is monitored?
- Understanding baseline patterns e.g. migration
- Changes over time in response to stressors e.g. climate change
What are 2 ways of monitoring biodiversity?
- Conservation drones (low cost, monitor + map terrestrial/aquatic ecosystems, support enforcement of protected areas)
- Camera traps (remotely activated camera with motion/IR/light sensor as trigger, detect elusive species,
can be used at remote/inhospitable sites, mark-recapture studies)
What 3 things do good indicator species for monitoring have?
- Sensitive enough to detect changes
- Widely distributed
- Provides continuous assessment over a wide range of stress
Define mass extinction
Times when Earth loses more than 3/4 of its species in a geologically short interval
How many mass extinctions have there been so far?
5 (may be entering the 6th)
