what to conserve? conservation units (lecture 2) Flashcards
Why select conservation units?
- essential for effective and efficient planning given limited resources
- the aim is to protect biodiversity
- biodiversity = variability among living organisms: within species/between species/ecosystems
- have to select from these units
What is yearly required versus actual spend on conservation?
- James et al., 2001
- McCarthy et al., 2012
- James et al: required $27.5B, actual $6B (20%)
- McCarthy et al: required $78B, currently at 10% of this
What units of conservation do taxonomic and ecosystems approaches encompass?
Taxonomic:
- genetic diversity
- populations
- sub-species
- species
Ecosystems:
- habitats
- ecosystem services
Why use genetic diversity as a conservation unit?
- important for population resilience (small population paradigm)
- in plants may be useful for improving yields in closely related crop species
- varies spatially
What are problems with genetic diversity as a conservation unit?
- focus on genetic diversity or genetic uniqueness?
- is it practical?
- are there more practical surrogates for genetic diversity?
Why use populations as a conservation unit?
Multiple populations = higher probability of:
- maximising genetic diversity
- protecting local adaptations
- insurance against local disasters
What are problems with populations as a conservation unit?
- while some distributions are obvious others are less clear
- is each isolated distribution a distinct population?
- populations can be difficult to define
- based on rarely tested assumptions of genetic divergence between populations
- often there are multiple populations, rarely pragmatic to save them all
- focus on local concerns instead of global priorities
- can lead to narrow outlooks and inefficient conservation
Example of the problems with populations as a conservation unit:
- great cranes project
- common cranes extinct in UK circa 1600
- cranes recolonised ~ 1980
- 2009 great cranes project started
- £400,000 per year on trying to increase UK common crane population
BUT - common crane populations in Europe have seen large increases since the 1990s
- common cranes are “least concern”
- 11 other crane species globally threatened with extinction
- e,g, siberian crane is critically endangered, black-necked crane is vulnerable, neither is getting enough spent on them
Why use subspecies as a conservation unit?
- surrogate for genetic diversity
- idea that conserving a species genetic diversity is more likely if you conserve all its subspecies
What are problems with subspecies as a conservation unit?
- subspecies doesn’t mean genetic distinctiveness
- Zink (2004) 97% continentally distributed avian species lack genetic distinctiveness
- subspecies based conservation problematic bc
a) incorrectly assumes subspecies always represent genetic variation
b) promotes parochial conservation
Example of the problems with subspecies as a conservation unit:
- dusky seaside sparrow
- subspecies restricted to florida
- $2.5 million investment
- declared extinct 1990
- another non-threatened subspecies was genetically identical
Why use species as a conservation unit?
- traditional conservation unit
- species are irreplaceable
- pragmatic:
- public understand it
- unit at which biological data is most frequently
gathered - relatively easy to recognise & define (legally
important)
What are problems with species as a conservation unit?
- unstable taxonomy: shearwaters, inflation
Shearwaters:
- 2 species were split in the early 1990s
- manx shearwater = least concern
- balearic shearwater = critically endangered, declining 7.4% a year, will be extinct in 40 years
Taxonomic inflation/progress?:
- albatross: now 21 species, used to be 13
- lemurs: 33sp in 1994, 70 in 2006, now about a hundred
- Philippines may have more than 100 more avian endemics than currently defined
What are problems with species as a conservation unit?
- unstable taxonomy
- most species not described
- especially true for non-charismatic species
Why use habitats as a conservation unit?
- response to accusations that species based conservation ignores many species
- pragmatic:
- reasonably good data on habitat loss
- protecting habitats gives a good chance of
protecting species that live there - habitat loss is a major driver of extinction risk
- 80% of terrestrial vertebrates threatened with
habitat loss
- protect ecosystem services e.g. watershed management relying on intact forest (utilitarian approach)
What are problems with habitats as a conservation unit?
- broad-scale habitat definitions (e.g. forest type) and loss are pretty easy to define but it is more difficult at finer scales
- some species have such small ranges that broad habitat conservation won’t do it
What are ecosystem services?
- benefits of ecosystems to human wellbeing
- humans are buffered by technology/culture but ultimately rely on ecosystem services
What are supporting ecosystem services?
- necessary for production of other ecosystem services
- e.g. primary production, nutrient cycling, soil formation
- often excluded from economic evaluations to prevent double counting
What are provisioning ecosystem services?
- resources obtained from ecosystems
- e.g. wood, fibre, food, freshwater
What are regulating ecosystem services?
- benefits obtained from the regulation of ecosystem processes
- e.g. climate regulation, flood regulation, disease regulation, water purification
What are cultural ecosystem services?
- non-material benefits to human wellbeing
- e.g. aesthetic, mental well-being, recreational activities like fishing and ecotourism
Provisioning ecosystem services:
- pollination
- productivity
Pollination:
- $27B dollars a year globally
- (Klein et al., 2007)
Productivity:
- debate as to whether it increases with plant species richness or if only a few really contribute
- when various conditions accounted for however most species enhance service provision in one or more scearios
Regulating ecosystem services:
- flood defence
- super-cyclone, India Orissa 1999
- mangrove forests significantly reduced death in villages less than 10km from the coast (Das and Vincent, 2009)
Cultural ecosystem services:
- well-being
- children in high-rise flats have better concentration levels when views of green spaces are availability (Taylor et al., 2002)
- people in parks with more plant species have higher mental wellbeing scores (Fuller et al., 2007)
