what to prioritise? sites (lecture 4)

Question 1

Why target sites?

• protected areas
• wider landscape conservation
• specific management

Answer 1

protected areas:

• Aichi protected area coverage aims by 2020: 17% land/freshwater & 10% marine
• 50% earth goal not viable bc many ecoregions have less than half of their natural habitat left

wider landscape conservation:
- e.g restoration, agri-environment schemes

specific management:
- e.g. invasive species control

need to select sites to maximise effectiveness

Question 2

What are the two scales of prioritisation?

Answer 2

global scale

• selection of large regions of conservation value
• e.g. madagascar, 12,000 endemic species
• well defined prioritisation schemes
• but conflicting and not as robust as ideal

local scale

• which specific localities within these hotspots
• limited standardisation
• most rigorous is Ratcliff’s UK scheme

Question 3

What are the nine prioritisation strategies on a global scale?

Answer 3

• crisis ecoregions (CE)
• centres of plant endemism (CPE)
• high biodiversity wilderness areas (HBWA)
• biodiversity hotspots (BH)
• megadiverse countries (MC)
• frontier forest (FF)
• endemic bird areas (EBA)
• global 200 ecoregions (G200)
• last of the wild (LW)

Question 4

How is vulnerability used by global scale prioritisation strategies?

Answer 4

vulnerability can be in terms of:

• % habitat lost (assumes past lost predicts future loss)
• human population (ok indicator)
• protected area coverage (ok indicator)
• total forest cover (poor indicator)
• none use number of threatened species!!

Question 5

Are low or high vulnerability sites more important to conserve?

Answer 5

Proactive prioritisation focuses on low vulnerability areas:

- frontier forests, last of the wild, high biodiversity wilderness areas

Question 6

What are irreplaceability indicators?

Answer 6

• most common is endemism
• used by four strategies in terms of plants and one in terms of birds
• reasonably assumes strong relationship between endemism in different groups

Question 7

Why don’t any irreplaceability indicators rely entirely species richness?

Answer 7

• incorporated into WWFs 200 ecoregions

- this is good bc common species less in need of conservation can determine species richness patterns

Question 8

What influence has Ratcliffe (1977) A Nature Conservation review had?

Answer 8

• criteria have had major influence inside and outside of UK
• principles apply when selecting a site/group of sites
• critical assessment of criteria provides a good understanding of the key issues

Question 9

What are Ratcliffe’s criteria?

Answer 9

• size
• diversity
• rarity
• naturalness
• fragility
• typicalness
• recorded history
• position in ecological/geographic unit
• potential value
• intrinsic appeal

DIDN’T factor in cost but should have

Question 10

Why prioritise site size?

Answer 10

• larger site = more species
• species-area relationship
• non-linear, yields relatively little benefit after threshold level
• threshold varies b/w region/taxa
• larger sites = larger populations
• larger reserves = fewer edge effects

Question 11

What are types of edge effects?

Answer 11

human activities extending into reserve areas:
- e.g. resource extraction, pesticide drift

animal movement outside of reserves

• animals w large home ranges more likely to move out of smaller protected areas
• wide-ranging carnivores suffer higher extinction risk in fixed-size reserves than those with smaller home ranges when accounting for population size (Woodroffe and Ginsburg, 1998)

Question 12

Why prioritise site diversity?

Answer 12

• high habitat diversity promotes species richness

- many species need multiple habitat types e.g. altitudinal migrants and amphibians

Question 13

Problems with prioritising site diversity?

• habitat diversity
• species diversity

Answer 13

• high habitat diversity is only good if all habitats are high quality
• high habitat diversity can reduce species diversity at small sites
• habitat specialists can’t maintain viable populations if each habitat type is tiny
• species richness too simple, depends on priorities
• area with 200 species but 1 endemic maybe less important than are with 100 species but ten endemics

Question 14

Why prioritise rarity?

Answer 14

• rarity must be looked at along with long-term viability
• e.g. natterjack toad SSSI guidelines
• all established and important sites
• established = occupied for > 5 years
• important = higher populations than average (100 individuals or 25 spawn springs for two of the last 5 years)
• rarity vs threat
• in uk many species threatened with extinction

Question 15

Why prioritise naturalness?

Answer 15

• areas least modified by humans should be prioritised
• difficult to quantify
• human modified areas can be valuable

Question 16

Why prioritise fragility/threat?

Answer 16

• sites w more threatened species/habitats most worthy of protection
• IF threat can be countered by site-based protection
• not the case for many threats e.g. nitrogen, acid rain

Question 17

Why prioritise typicalness?

Answer 17

• sites most characteristic of focal habitat are better
• set of indicator species are representative of habitat X
• compare ideal species set with those at site
• closer match = more typical
• is conserving the “average” a good aim?

Question 18

Why prioritise recorded history?

Answer 18

• sites with long history of ecological research need protection
• e.g. whytham woods, oxford; barro colorado island, panama

Question 19

Why prioritise position within an ecological or geographic unit?

Answer 19

• sites at edge of distributions may be of more value
• data on limiting conditions can inform management
• unique local adaptations
• facilitate range shifts in response to climate change

Question 20

Why prioritise potential value?

Answer 20

need to consider if a sites value will increase in future
- e.g. through habitat restoration like at Lakenheath

climate change can increase or decrease site values in future (Hole et al., 2009)

• change habitat type
• focal species may move away
• new species may colonise
• most sites retain high (but different) value

value of site for education

Question 21

Why prioritise intrinsic appeal?

Answer 21

• idea sites with charismatic taxa more important
• highly controversial and often considered wrong
• BUT if wishing to retail recreational ecosystem services may be correct

Question 22

Beyond Ratcliffe’s criteria: why prioritise representation?

Answer 22

• focal species must be represented by at least one viable population in a protected site
• Ratcliffe assumed this would be the result if his criteria followed but not necessarily case
• 300 critically endangered vertebrates occur entirely outside protected areas globally

Question 23

Beyond Ratcliffe’s criteria: why prioritise cost effectiveness?

• invasive species eradication

Answer 23

• e.g. invasive species eradication on islands
• 2 priority lists: conservation benefits / conservation benefits per unit cost
• totally different results
• 3 highest change
• only 13 islands in top 20 priorities on both list
• second list 2-7x more cost effective

Question 24

Beyond Ratcliffe’s criteria: why prioritise cost effectiveness?

• australian nature reserves

Answer 24

• target 15% of each of 58 major habitats in protected areas
• benefit increases with cost, but massive variation
• replacing least effective 1% keeps costs identical but increases number of habitats meeting the target from 18 to 54