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Threats to Biodiversity chap 3. “ Extinction is the most irreversible and tragic of all environmental calamities. With each plant and animal species that disappears, a precious part of creation is callously erased ” Michael Soule, 2004. Threats to Biodiversity.

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threats to biodiversity chap 3

Threats to Biodiversitychap 3

“Extinction is the most irreversible and tragic of all environmental calamities. With each plant and animal species that disappears, a precious part of creation is callously erased”

Michael Soule, 2004

threats to biodiversity
Threats to Biodiversity
  • As our numbers climb, we expand agricultural conversion, import invasive species, hunt more species, degradate habitat, fragment and lose habitat, pollute water and air, impact climate…
  • In short, we are causing the 6th mass extinction, the only biological driven one
threats to biodiversity3
Threats to Biodiversity
  • Major factors impacting biodiversity
threats to biodiversity4
Threats to Biodiversity
  • Habitat Degradation
  • Includes conversion from suitable to unsuitable, lowering quality, fragmentation that lower PVA
  • Causes: many industries (e.g. forestry, agriculture, development, fishing, mining, chemical)
threats to biodiversity5
Threats to Biodiversity
  • Overexploitation
  • Hunting, collecting, fishing (and indirect by-catch), trade of animals (and parts)
threats to biodiversity6
Threats to Biodiversity
  • Invasive Species
  • With our help, species have the ability to get virtually anywhere in the world
  • Direct actions: predation, parasitism, disease, competition or hybridization
  • Indirect paths: changing abundances, disruption of mutualisms, modifying habitat, reducing habitat quality)
threats to biodiversity7
Threats to Biodiversity
  • Anthropogenic Climate Change
  • Climate has been a cause of previous mass extinctions
  • Couple this with lower abundance, invasive species and other problems, a severe impact is likely from climate change
  • Climate change will also trigger additional biological responses (e.g. malaria in temperate places)…Fig 3.3
threats to biodiversity8
Threats to Biodiversity
  • “Snowballing” effect of the invasion of the alien root pathogen
threats to biodiversity9
Threats to Biodiversity
  • “Snowballing” effect of the invasion of the alien root pathogen
  • Indirect effects
threats to biodiversity10
Threats to Biodiversity
  • Anthropogenic Pollution
  • There are direct discharges of chemicals into the environment, there are also pollutants released into the atmosphere
  • Toxic chemicals (e.g. mercury, lead) are found even in remote areas
  • Also have the problem of bioaccumulation (or biomagnification)
threats to biodiversity11
Threats to Biodiversity
  • Toxic chemicals (PCB’s and dioxins) accumulate in fatty tissues
anthropogenic extinctions impact on communities and ecosystems
Anthropogenic Extinctions… impact on communities and ecosystems
  • Loss of species, populations and/or habitat is dramatic and extreme
  • Extinction as a process…
  • Can be local or global (also, ecological)
anthropogenic extinctions impact on communities and ecosystems13
Anthropogenic Extinctions… impact on communities and ecosystems
  • Early extinctions probably caused by overexploitation
  • Now, habitat degradation and/or invasive species major factors
anthropogenic extinctions impact on communities and ecosystems14
Anthropogenic Extinctions… impact on communities and ecosystems
  • No. of genera (megamammal) extinct and cause
  • 72% Aust
  • 88% NAm
anthropogenic extinctions impact on communities and ecosystems15
Anthropogenic Extinctions… impact on communities and ecosystems
  • Consider Polynesian colonization of Pacific Islands 1-3KYA
  • Over 2000 species of birds (flightless rails) and 8000 populations driven to extinction
  • Story is not so simple…
  • Where invasive sp and habitat degradation combined, extinction followed
anthropogenic extinctions impact on communities and ecosystems17
Anthropogenic Extinctions… impact on communities and ecosystems
  • Since 1500, >129 sp extinct
  • Habitat loss major cause
  • Invasive sp contributed for many
  • Overexploitation for 1/5
anthropogenic extinctions indirect impacts
Anthropogenic Extinctions… indirect impacts
  • Species don’t exist in a vacuum and extinctions usually have a ripple effect
  • ‘Cascade effects’ such as secondary extinctions may occur
  • E.g. plants with a single sp pollinator or seed dispersers
  • E.g. sea otters and sea urchins
anthropogenic extinctions indirect impacts20
Anthropogenic Extinctions… indirect impacts
  • E.g. sea otters and sea urchins
anthropogenic extinctions indirect impacts22
Anthropogenic Extinctions… indirect impacts
  • Another problem is the removal of top predators, which may cause the ‘ecological release’ of mesopredators
anthropogenic extinctions indirect impacts23
Anthropogenic Extinctions… indirect impacts
  • So there are many important species in a given community and some are more important than others
  • Dominant sp: common, but also have strong effects on other members
  • Ecosystems engineers: those that modify the ecosystem (e.g. beaver, elephant)
  • Keystone sp: sp that has more impact on community than numbers (biomass) would suggest (e.g. bat pollinator)
current patterns of global endangerment
Current Patterns of Global Endangerment
  • Best data on global endangerment are collated in the IUCN Red List of Threatened Species (www.redlist.org)
  • All species placed into one of 9 categories (3 primary categories: Critically Endangered, Endangered, Vulnerable)
  • To date, only 2.5% of species evaluated (and 41% considered endangered)
current pattern of global endangerment28
Current Pattern of Global Endangerment
  • What groups are in endangered?

Turtles at 42%

current pattern of global endangerment29
Current Pattern of Global Endangerment
  • Globally threatened processes
  • Some dramatic phenomenon may disappear (e.g. large-scale migrations)
  • Read Essay 3.3
current pattern of global endangerment30
Current Pattern of Global Endangerment
  • Factors threatening biodiversity
  • Factors are listed in the Red List
  • Knowledge varies tremendously and by taxonomic group and habitat
  • Most face multiple threats and threats can act synergistically
current pattern of global endangerment31
Current Pattern of Global Endangerment
  • Overexploitation is major cause for fish
current pattern of global endangerment32
Current Pattern of Global Endangerment
  • Where are sp most at risk worldwide?
  • Not all biomes (and their inhabitants) are equally at risk
  • Most tropical habitats and grasslands have large substantial numbers of threatened vertebrates
current pattern of global endangerment the us
Current Pattern of Global Endangerment…the US
  • Geographically, there are very high numbers in SAm, SE Asia, sub-Saharan AF, Oceania, and NAm (where?)
  • The US is second (Ecuador) for the number of species though to be at risk of extinction globally (IUCN)
  • Many are plants (>5000sp), freshwater species (e.g. mussels {70%},crayfish, stoneflies)
current pattern of global endangerment the us35
Current Pattern of Global Endangerment…the US
  • Proportion of sp threatened in US
current pattern of global endangerment the us36
Current Pattern of Global Endangerment…the US
  • Examining threats to US sp

A correlative cause of many of these factors is urbanization

current pattern of global endangerment37
Current Pattern of Global Endangerment
  • Threatened species in other countries
  • Unfortunately, many countries lack solid data on what and how many sp are actually in trouble
  • Some countries have a high proportion of the flora and fauna at risk
  • E.g. Madagascar 80% of plants and 30% of vertebrates (case study 3.2)
current pattern of global endangerment39
Current Pattern of Global Endangerment
  • What types of sp are most vulnerable?
  • Through studies, we have determined there are ‘suites’ of characteristics that make some sp more vulnerable
  • E.g. large range requirements, narrow habitat range, rarity, low reproductive rate, extreme specialization or co-evolutionary dependancies
current pattern of global endangerment40
Current Pattern of Global Endangerment
  • Vulnerability due to Specialization
  • Many species (especially tropical) have narrow environmental ranges and highly specialized diets or habitats
  • Perturbations can easily disturb them
  • Specialization on other species can be precarious as well
current pattern of global endangerment41
Current Pattern of Global Endangerment
  • Top carnivores with low densities, large ranges, large body size, are often cited as being vulnerable to habitat degradation, as well as overexploitation
  • For marine animals, body size itself does not appear to be a problem, but is associated with another…

low reproductive rate

current pattern of global endangerment42
Current Pattern of Global Endangerment
  • Vulnerability of Rare species
  • Why might a species be rare?
    • Consider 3 characteristics: geographic range, habitat breadth and abundance
  • How might each influence vulnerability?
  • How might they interact?
current pattern of global endangerment43
Current Pattern of Global Endangerment

vent sp

Island sp

bats

big cats

raptors

seabirds

current pattern of global endangerment44
Current Pattern of Global Endangerment
  • Let’s consider a case of extreme endemism: ‘Centinela Ridge’ in Ecuador
  • During a RAP inventory, 90 endemic plant species were discovered
  • Immediately following the inventory, entire ridge cleared for agriculture
current pattern of global endangerment45
Current Pattern of Global Endangerment
  • Island communities have relatively high rates of endemism, although communities maybe less rich than comparable mainland sites
  • However, many island biotas are frequently endangered; why?
current pattern of global endangerment46
Current Pattern of Global Endangerment
  • Case Study: birds of Channel Islands
  • 80 year comparison of pop(s)
    • 40% of small pop(s) went extinct (<10 bp)
    • 10% of pop(s) with 10-100 breeding pairs
    • 1 population of 100-1000 bp
    • No pop(s) if >1000 bp
current pattern of global endangerment47
Current Pattern of Global Endangerment
  • “Bad luck” species do not have intrinsically vulnerable traits, just bad luck
  • For example, many freshwater fish near large cities are vulnerable, whatever their LHC
  • 50% of variation in extinction risk for primates and carnivores is strictly due to anthropogenic distrubances
current pattern of global endangerment48
Current Pattern of Global Endangerment
  • Economic and Social Context
  • Economic growth and rising affluence drive habitat conversion and overexploitation
  • Unfortunately in the US, areas of high endemism and richness are areas of high human growth (e.g. s. CA, e-c TX, s FL)
current pattern of global endangerment49
Current Pattern of Global Endangerment
  • At the other end of the economic spectrum, billions live in poverty
    • 1B < $1/day
    • 2.7B < $2/day
  • As a result, unsustainable levels of burning, small-scale agriculture, grazing and bushmeat hunting occur wherever these practices help people survive
current pattern of global endangerment50
Current Pattern of Global Endangerment
  • Responses to the Biodiversity Crisis
  • Conservationists and developers agree where solutions need to come from:
    • 1) scientific analysis and promotion of the causes of biodiversity change
    • 2) technological improvements
    • 3) legal and institutional instruments
    • 4) economic incentives and plans
    • 5) social interventions
current pattern of global endangerment51
Current Pattern of Global Endangerment
  • Solutions will include:
    • Establishing protected areas
    • Targeted interventions at the genetic, species, and ecosystems levels
    • Restoration of damaged ecosystems
    • Recovery of endangered species
    • Creation of sustainable forms of development
current pattern of global endangerment52
Current Pattern of Global Endangerment
  • Single-species approaches will not be enough to conserve ‘biodiversity’…larger spatial scales are going to be needed
  • However, many conservation actions are achieved at smaller scales (i.e. local)
  • Need to prioritize and plan at larger scales (consisting of local partners)

Conservationist’s are generally asking “where” questions to set geographical

priorities and “how” questions about developing and implementing strategies

to conserve conservation targets at priority places Redford 2003

laws and international agreements
Laws and International Agreements
  • One major tool for conservationists are US laws and international agreements
  • Please Review Case Study 3.3!!
driving factors and trends in species endangerment
Driving Factors and Trends in Species Endangerment
  • The first step is identifying a trend
  • The second step is to determine what factors most influence trends
  • Finally, establish a plan to remove or eliminate the identified threats
  • As easy as they sound, none of these steps are as easy as they appear and the further along, the more ‘external’ factors enter the process
driving factors and trends in species endangerment55
Driving Factors and Trends in Species Endangerment
  • Besides developing a plan for a single species, important to track ‘status’ trends to determine success
  • The Red List Index tallies changes in status due to either a deterioration or improvement of all threatened species
driving factors and trends in species endangerment56
Driving Factors and Trends in Species Endangerment
  • Overall, birds down 7%
  • Albatrosses and petrels down 25%
driving factors and trends in species endangerment57
Driving Factors and Trends in Species Endangerment
  • Unfortunately most species groups are too poorly known to adequately evaluate trends
  • However there are a number of indicies attempting to bridge these gaps
  • IBI (index of biotic integrity), LPI (living planet index; pop change of 1100 terrestrial, marine, and freshwater vertebrate sp)
driving factors and trends in species endangerment58
Driving Factors and Trends in Species Endangerment
  • Terrestrial sp (A) and broken down
driving factors and trends in species endangerment59
Driving Factors and Trends in Species Endangerment
  • It is not enough to determine where changes are occurring (reactive), but rather perhaps we can use information to generate predictive models of what species or systems may be more vulnerable than others (proactive)
driving factors and trends in species endangerment61
Driving Factors and Trends in Species Endangerment
  • In the end, it is essential we better understand the factors that drive human behavior, which ultimately drive the causes of biodiversity loss