MBIO162 Big Picture Biodiversity

21 January 2025: Intro to Biodiversity


  • Rio Summit (1992)

    • Convention on Biological Diversity 

    • Treaty siged June 5th, 1992

      • Came into force 18 years laters

    • Raitified by 150 nations (not the US though)

  • Notion and measurements of biodiversity 

    • Possible definition 

      • Variety of life in all its’ manifestations 

    • No such thing as the biodiversity of an area/group of organisms

      • Only measures of certain components possible – even then only appropriate for restricted purpose

        • I.e. populations

    • Surrogacy

      • Correlates of the measure of biodiversity that you want

        • Example: number of species of x correlates with number of species of y 

    • Species richness

      • Good surrogate

        • Common currency of biodiversity 

        • Acts as an ‘integrator’ of many facets of differences in biodiversity

      • Relatively easy to measure

      • Substantial amount of info already exists (or can be extracted from museums/scientific data)

      • More difficult for microbial diversity (limited literature)

    • Environmental DNA (eDNA)

      • Potential to revolutionize biodiversity science/conservation census of species on a global scale in near real time

      • Important in aquatic systems – less so terrestrial

      • Current eDNA methods

        • Require refinement/ improved/ calibration/validation at every level

        • Better understanding eDNA “natural history” needed 

          • Origins, state, lifetime, and transportation-physical and ecological limitations of eDNA use


21 January 2025: Species relatedness

  • What is a species?

    • Taxonomic unit – fundamental to all of biology

      • At least 7 different definitions

      • Morphological species (most commonly used)

        • Smallest natural populations permanently separated from each other by a distinct discontinuity in heritable characteristics

      • Biological species

        • Interbreeding natural population that do not successfully mate/reproduce with other groups

      • Evolutionary species

        • Single lineage of ancestor-descendent populations distinct from other such lineages and which has its own evolutionary tendencies and historical fate

  • How many species?

    • Counted in OTUs (operational taxonomic units)

    • Estimated 13.62 million exist currently

      • Only 1.75 million are currently described 

      • ~13,000 new species are discovered every year

        • Biodiversity is not evenly distributed between groups

          • Most animals are insects

          • Most species of plants (>75%) are angiosperms (flowering)

          • Most species of mammal are rodents

  • Historical context

    • Aristotle

      • Great chain of being within animals

      • Progress to sanguineous (with blood) from non-sanguineous

    • Carl Linnaeus

      • Hierarchical classification of life

        • Kingdom, Class, Order, Family, Genus, Species

      • Based on how organisms look, no interspecies relationships

    • Darwin

      • Theory of Evolution (late 19th/early 20th century)

        • Introduction of relationships

    • Whittaker (early 1960s)

      • 5 Kingdom approach 

        • Similar to Aristotle’s ideas

        • Empathized macroscopic over microscopic life

    • Woese (late 1970s)

      • Classification based on DNA/RNA

      • 5 vs. 3 kingdoms debate



22 January 2025: Where is biodiversity?


  • Issues of scale 

    • Species-area relationship – principle pattern

      • As the size of a geographical area increases so does the number of species it contains

      • Practical use – predict that as area is reduced, tendency to lose species

      • Habitat loss/fragmentation – major determinant of modern extinctions

      • Patterns may be obscured

        • Ex. By gradients 

          • Costa Rica (1/6th land area of UK) has 1.5-2.0 k butterfly species, the UK has 60

    • Local-regional diversity

      • Local-regional diversity relationships

        • As an entire desert has fewer insects than an entire forest so a small area of the desert has fewer species than similar sized piece of forest

      • Local species richness tends to be an increasing function of regional richness

        • Thus changes in global biodiversity tend to be reflected in local biodiversity – and vice versa

  • Biodiversity extremes (high and low)

    • Sea/land comparison 

      • All animal phyla (approx. 34) occur in the sea (one exception – velvet worms (Onychophora))

        • Two-thirds (20) almost exclusively marine

      • However, only 15% of named species are marine

        • Of these 98% live in/on the sea floor (are benthic)

        • 2% live floating or swimming in the sea (pelagic)

        • WoRMS (World Register of Marine Species contains >250 k species)

      • SEA vs LAND

        • SEA:

          • Very few, large photosynthetic organisms – mainly short lived, microscopic algae

          • Dominant herbivores – micro (copepods)

            • Majority of large animals are carnivorous

          • Grazing – ingestion of entire autotroph

          • Food chain averages 5 links

        • LAND:

          • Dominated by persistant long-lived ‘large’ flowering plants

          • Dominant herbivores can (and often) are large

          • Grazing – rarely removes significant amounts of communities (indigestible, e.g. wood)

          • Food chain averages 3 links

      • Distribution of marine biodiversity

Littoral/sublittoral

Bathyal

Abyssal

Hadal

Area of sea bed (%)

8

15

76

1

Depth (m)

0-200

200-4,000

4,000-11,5000

6,000-11,5000

Pressure (atm)

1-21

21-401

401-1151

601-1151

Temp (°C)

5-25

5-15

<5

<3.5


  • High/low extremes

    • Biogeographic regions 

      • Works well for terrestrial systems

        • Ex. 3-4 tropical regions contains >2/3 biodiversity

          • Neotropics greatest biodiversity

      • Doesn’t work quite so well for marine systems – more open Indo-Western Pacific – highest marine biodiversity

    • Trends

      • Tends to be at level of groups of countries, i.e. little biological reality but level at which conservation/political decisions are made

        • Mega-diversity countries – 50-80% of world’s biodiversity tend to also be poorer countries

          • Ex. Central and South America, East Africa, etc.

      • Endemic taxon (number of endemic species increases the closer you get to the tropics)

        • Evidence mainly from terrestrial vertebrates that high endemism found in areas of high species richness

  • Gradients

    • Latitude

      • Alexander von Humboldt (1799 → onwards)

        • Venezuela – Mexico: species identity differs with latitude

      • Alfred Russell Wallace 

        • Number of species increases as you go from temperate to tropic regions 

        • Steepness of terrestrial gradient varies dramatically based on species

          • Ex. ants have a more gradual curve, lizards more steep

            • Some exceptions ex. marsupials

          • Pattern is indisputable but mechanism are debatable

            • Possible theories

              • Must be product of origination, immigration, extinction & emigration

              • Large scales – origination & extinction.

              • Thus tropics or a ‘cradle of diversity’ – high origination rates and a ‘museum of diversity’ – low extinction rates

      • Marine patterns

        • Planktonic diversity: occurs in all three domains of life

          • Overall decline in diversity toward the poles (fits with pattern on land)

          • Driven by decreasing water temperatures

        • Shallow waters:

          • Complicated - evidence for and against latitudinal gradient coastal marine fish/bacteria - increase in species richness  towards the equator

            • Coral reef fish - no pattern

            • Amphipods/isopods/bivalves – highest before they reach the equator

        • Deep sea:

          • Increase in richness towards equator for a number of taxa bivalves, gastropods and isopods…. BUT not all foraminiferans – highest before they reach the equator

        • Pelagic:

          • Increase in richness towards the equator - ostracods, euphausiids (krill), shrimp, fish (N. Hemisphere), bacteria, most pelagic taxa

        • Generally the pattern in marine environments is similar to the one seen in terrestrial areas

    • Elevation 

      • Von Humboldt

        • Kimboraza (Ecuadorian Andes)

        • No. & type of plant species changed as he ascended the volcano

        • Observations 

          • Species richness decreases with increasing elevation

            • But hump-shaped pattern when standardise for area and sampling effort

    • Below the Earth’s surface

      • Endemic cave communities,

        • Ex. Movile, Romania

      • Chemosynthetic ecosystem discovered in 1986

      • Bacterial assemblages (62 different types)

        • 4 km underground

    • Depth

      • Animals in the ‘deeps’ Bay of Lyons (1725)

      • 420 metres depth in Aegean sea (1750)

      • Edward Forbes (1841)

        • HM survey ship (Beacon)

          • Hypothesis of zero animal life was probably about 300 fathoms (~550 m) below the surface which extended into a lifeless or azoic zone (1841)

            • Azoic zone hypothesis shortlived

              • Brittlestar found on a rope from 2.3 km deep (1860)

      • Late 1990s and 2000s

        • Overall decrease in species richness with increasing depth

        • Diversity peaks at intermediate depths (0.3 – 4.7 km)

        • Pelagic peak - more shallow than benthic

        • Pressure and temperature thought to limit species richness

  • Congruence (putting the bones together)

    • Different, well known groups on their own may not show congruence 

      • BUT 

        • The summed biodiversity of these groups may be taken as best approximation of overall spatial biodiversity we have

          • Family richness:

            • Seed plants, amphibians, reptiles & mammals

          • Hotspot of max. richness in central Columbia

            • Others in Malaysia, Nicaragua, Mexico, southern Columbia

              • Strong latitudinal pattern


23 January 2025: History of biodviersity 


  • Pre-Cambrian (before life)

    • Age of Earth 

      • 4.540 mya

    • Earliest living organism (3.465 mya)

      • P. amoenum and A. disconformis

        • Found in a 3,465 mya Carbonaceous chert clast

    • Earliest animal (550 mya)

      • Dickinsonia (Ediacaran fauna)

        • Worm-like animal

      • Ediacaran fauna were earliest animals (600-550 mya)

        • Garden of Ediacara

          • Earliest animals

            • Strange shapes

            • Sheet/leaf like

            • Soft bodies

            • (Most) no mouth or gut

              • Must contain photosynthetic algae (McMenamin, 1986)

                • Seilacher (1989) - contain symbiotic algae/bacteria - use chemosynthesis

                  • Similar to hydrothermal vent fauna

            • Adapted to low O2 levels

              •  (i.e. 7-10% present day)

          • Traditional vs. Seilacher’s view:

            • Ancestors of present day animals

            • VERSUS

            • Early failed ‘experiment’

              • No descendants

  • Cambrian explosion 

    • Sudden appearance of all major animal groups (550 mya)

      • First animals with hard parts

        • Examples:

          • Arthropod (trilobite-most dominant form), Graptolite (Hemichordata), Mollusc (snail) Archaeospira, Brachiopod (lamp shell), Chordate Pikaia (group to which vertebrates belong)

    • Why now?

      • 1. Continents breaking up

        • Increased area of continental shelf → appearance of shallow seas → new habitats

      • 2. Climate

        • Much warmer than today

        • Critical O2 level

      • 3. Developmental genetics and origin of major phyla

        • Right place at the right time

        • Development or mutation of single Hox gene - huge morphological change

          •  Mechanism for initial rapid evolution of body plans

    • “Wonderful life” (Burgess Shale fauna)

      • Discovered - Walcott 1910s

      • “Rediscovered” - Whittington 1960s

      • Species present:

        • Typical of Cambrian faunas

        • Many soft-bodied forms

        • Forms familiar - also forms strange

        • Most common species was the trilobite Marrella

      • Two books came out of the discovery 

        • Gould

          •  Many novel designs - very few successful

          •  Re-run the  ‘tape of life’ - everything is different

          • Successful species/designs are lucky, not necessarily well adapted

        • Conway-Morris

          • Too much made of novelty

          •  Re-run the ‘tape’ -  largely the same

          • “Best” designs always win

  • Post-Cambrian 

    • 542-500 mya

      • Pattern:

        • Cambrian (Cm)

          • Start: huge radiation major groups appear

          • End: Stabilization of many of new groups - little ecological specialisation

      • Events:

        • Cambrian (Cm)

          • Appearance of all the major groups including jawless fish and marine ‘plants’

    • 500-300 mya

      • Pattern:

        • Ordovician (O) → Permian (P)

          • Huge increase in Biodiversity. 

          • Then ‘stable’ for ¼ billion years

          • Little ecological specialization in sea

      • Events:

        • Ordovician (O)

          • Appearance of jawed fish (cartilaginous & bony)

        • Silurian (S)

          • First land plants

        • Devonian (D)

          • ‘Age of fish’ 

          • First amphibians

          • Earliest insects

        • Carboniferous ©

          • Huge terrestrial forests dominate

          •  First reptiles

    • 300-250 mya

      • Pattern:

        • Permian (P)

          • Ended with largest biodiversity crash known

          • End of Paleozoic (‘early life’)

      • Events:

        • Permian (P)

          • Appearance of mammal-like reptiles

          • Extinction of trilobites

    • 250-100 mya

      • Pattern:

        • Triassic → Cretaceous

          • Ended with largest biodiversity crash known

          • Beginning of Mesozoic (‘middle life’)

          • Rebirth of marine biodiversity but with very different forms that increases (with blips) to the present day

      • Events:

        • Triassic (T)

          • Marine: 

            • Expansion of shell breaking predators & disruptive sediment movers

            • Beginning of the ‘rule’ of marine reptiles

          • Terrestrial: 

            • Beginning of the ruling reptiles (and dinosaurs)

        • Jurassic (J)

          • Age of the ruling reptiles

        • Cretaceous (K)

          • Extinction of ichthyosaurs, plesiosaurs, mesosaurs and ammonites

          • Extinction of dinosaurs and flying reptiles

    • 100-0 mya

      • Pattern:

        • Beginning of 3rd era → the Cenozoic (C)

          • Biodiversity continues to increase exponentially (with small blips)

      • Events:

        • Paleogene (PG)

          • Beginning of the age of mammals and flowering plants (angiosperms) on land

        • Neogene (N) & Quaternary (Q)

          • Age of insects, molluscs, fish (again) and one particular mammal

    • 1950s-present day

      • Pattern: 

        • Anthropocene (A)

          • An age of human influence & unprecedented biodiversity decline

  • Lessons from the past

    • Five big extinctions

      • list the five here

    • Background extinction rates

      • Account for 96% of all extinctions over the past 600 myrs

      • Lifespan of species in fossil record 5-10 mya

    • Recovery from mass extinction

      • Recovery of communities in the fossil record (different species) is 5-10 mya

    • Sixth extinction event

      • We’re in it


28 January 2025: Value of biodiversity 


  • Direct-use: direct role of biological resources in consumption or production (marketable commodities); scale – enormous/multifaceted/difficult to evaluate

    • Food

      • Foundation of all food industries & related services (vegetables, fruit, nuts, meats, colourants, flavourings etc)

        • Mainly cultivated

        • Global agriculture 95% of all plant/animal protein

        • Half of habitable land used for agriculture

        • 99% energy consumed by humans

        • 1 billion people depend on ‘wild’ food (FAO 2020)

      • Plants

        • 370,000 species of flowering plants

          • 12,500 considered edible

        • 200 domesticated (2.7 billion tons/yr)

        • 75% of food supply – 12 kinds

          • Half of habitable land used for agriculture

      • Animal exploitation – more difficult to enumerate due to small no. of species

        • Insects

          • Moths, beetles, bees

        • Echinoderms 

          • Sea urchins/cucumbers

        • Vertebrates 

          • Fish, amphibians, reptiles, birds,mammals

        • Molluscs

          • Bivalves, gastropods, squid

        • Crustaceans 

          • Lobsters, crabs, shrimp

        • Statistics

          • Global seafood catch (2018) – 96.4 million tons (source UNFAO CCBY)

          • Global aquaculture (2018) – 114.5 million tons 

            • 527% increase since 1990

          • Avg. global annual meat production 320 million tons (2013) 

            • x4 than 50 years ago

    • Medicine 

      • >60% world’s population relies entirely on plant medicine for primary health care

      • Of new drugs approved (1940s – end of 2014) 49% are natural or derivatives

        • 1 in 125 plant species produced major drugs

          • Synthesised chemicals: 1 in 10 000 compounds tested

      • 35% of medicines derived from natural products ($385 billion.y-1)

        • Ex. Pacific yew Taxus brevifolia – discarded during logging

          • Contains taxol – anti-cancer (breast/ovarian)

            • Best seller ever >$1 billion annually

        • Ex. Wide diversity of peptides in venoms of tropical reef cone snails (block ion channels)

          • Omega-conotoxin (Ca channel blocker) acts as an analgesic (x1000 more than morphine)

            • Keeps nerve cells alive following ischaemia

        • Ex. Cancer treatment

          • Clinical trials – sea squirts & sea mats

          • Preclinical trials – sponge & snail

    • Biological control

      • Use of natural enemies to control problem species

        • Successful use of 30% weed biocontrol, 40% insect biocontrol

          • Huge economic gains

            • Control of cassava mealybug by encyrtid wasp

              • Cost benefit ratio 1:149

              • Saving over $260 million/year

    • Industrial materials

      • Wide range

        • Ex. building materials, dyes, adhesives, rubber, perfumes

          • Ex. wood: worldwide exports $6 billion (4.2% of total world export)

            • Harvest 3.8 billion m3 y-1

      • Biomimicry

        • Termite mounds → A/C systems 

        • Burdock seeds → velcro

    • Recreational harvesting

      • Hunting/fishing

      • Personal gardens

      • Botanical gardens (public and private)

        • Over 25,000 species

      • Zoos

        • 825 globally

        • 15k species

      • Aqauriums 

        • 14-30 million fish (2/3 coral reef species) traded yearly 

          • Legal trade in ‘wildlife’

        • Ornamental fish/invertebrates

          • $278 million (FAO 1996-2005)

        • Aquarium industry 

          • $1 billion AAPMA 2005

        • Commercial marine fish

          • $ 6-16.5 million

        • Coral reef fish

          • $500-1,800 million

    • Ecotourism 

      • Founded on biodiversity by definition

      • Global ecotourism generates $77 billion/yr

        • 5-7% overall travel & tourist market

        • Fast growing

      • Global terrestrial protected areas 8 billion visits/yr 

        • 80% Europe & NA

          • Generates $600 billion/yr (direct in country spend) 

          • $250 billion/yr  (consumer spend)  

          • Only $10 billion/yr spent on them

        • United Kingdom

          • Urban visitors to countryside → 650 million day visits  

            • Spent $7.5 billion/yr

      • Increase in the past several decades

        • 1998

          • 9 million whale watchers globally ($1 billion)

        • 2009 

          • 13 million whale watchers ($2 billion)

      • 590k shark-watchers globally spend $314 million/yr

        •  Supporting 10,000  jobs


  • Indirect use

    • Overview

      • 1015 gigatons) of C, H, N, O, P, S cycled annually

        • Living things modify physical/chemical conditions and create an environment suitable for life

          • Compared to other planets

Venus

Earth

Mars

CO2

96.5%

0.03%

95%

N2

3.5%

79%

1.9%

O2

Trace

21%

0.13%

Surface temp (°C)

459

13

-53

  • Ecosystem services and what they mean

    • Indirect-provides services crucial to human well-being & ‘free’

      • (i.e. not subject to direct trading)

    • Examples;

      • Atmospheric regulation

      • Climatic regulation

      • Hydrological regulation

      • Nutrient cycling

      • Pest control

      • Photosynthesis

      • Pollination

        • Ex. Wild bees are pollinators of agriculturally-important crops

      • Soil formation/maintenance

  • Can we provide ecosystem services?

    • Costs

      • 1997

        • World Gross National Product

          • 17 trillion

        • Estimated cost

          • 33 trillion

        •  Services would cost more than the global total annual gross national product

          • Gave rise to ecological Economics

      • 2014

        • World Gross National Product

          • 111.3 trillion

        • Estimated cost

          • 125-145 trillion

    • Attempts

      • Biosphere II modelled on I – feasibility of building on other planets

        • Project launched 1984

        • Cost $200 million

          • 1.27 hectares

          • Support 8 people and 4k animals/plants for 2 years

            • Used twice for closed system experiments 1991 and then 1994

              • In 1994 they achieved good food production

      • Now research arm of Columbia university → University of Arizona since 2011

        • Dedicated to actively promotes maintaining ecosystems on Biosphere I

  • Biodiversity and ecosystem function

    • Relationships between biodiversity/species richness and ecosystem function

      • Redundancy

        • Minimum no. of species needed

        • Most species equivalent

      • Rivet-popping

        • Loss of few species, little effect but beyond threshhold losses, function fails

      • Idiosyncratic

        • Function changes with diversity

        • It’s unpredictable as individual species have complex and varied roles

    • Still contreversial 

    • Seems that greater species richness increases:

      • Species redundancy

      • Resilience of ecosystem function through time

        • (Insurance effect) and so reliability of function

  • Non-use value

    • Option and bequest

      • Option value

        • Retaining biodiversity for options for future use & non use that it may provide, ex. genetic material as a source of novelty.

          • Species of no-known value may be valuable in the future

            • Ex. International Rice Research Institutes seed bank collection (1961) 

              • 1970s rice crops infected by grassy stunt virus; high yield rice in Asia lacked resistance 

                • Seed bank strain no longer in use was resistant

                  • 1976 redundant strain crossbred with other to make resistant strain

          • Extinction = loss of information

      • Bequest value

        • John Locke:

          • Each generation should bequeath, ‘enough and as good for others to future generations as justice demands it

        • ‘Compensate’ our children in the future for:

          • The loss of wealth, production, ecosystem services we are currently responsible for

            • CBD ..’determined to conserve and sustainably use biological diversity for the benefit of present and future generations.’

    • Intrinsic value

      • Organisms have worth irrespective of use/non-use value

        • Existence value (whether we see them or not) is difficult to categorize

          • But few would deny worth of species

        • Prevalent viewpoint (current):

          • We have an absolute moral responsibility to protect what are our only known (deities aside) living companions in the universe

        • Secular viewpoint:

          • E.O. Wilson – ‘Biophilia’

            • Humankind as ‘bearers of life’, natural empathy with other ‘bearers of life’

          • Intrinsic value also recognised in Convention on Biological Diversity (UN), as well as many other regional & international treaties

        • Religous viewpoint:

          • Faiths

            • Many religions (e.g. Buddhism, Hinduism, Jainism) consider humans an integral part of natural world

              • Claimed that religions that set humankind apart from and ‘above’ the natural world (Christianity, Islam, Judiasm) promoted an anti-biodiversity world view

                • Took the view of a resource to be exploited – but too simplistic

                  • Exploitation is present in countries/ages with more ‘biodiversity-friendly’ world views & the concept of stewardship is all important

        • The belief that biodiversity has intrinsic value is deep-seated and transcends history/religion/time


29 January 2025: Threats to biodiversity


  • Extinctions

    • Prehistory

      • Arrival of humans on land mass coincides with disappearance of megafauna

        • Oldest hunting cave painting Maros-Pangkep karst, Indonesia 43.9k years bp

        • We’ll never know what a completely natural system looked like

      • Possible anthropogenic contributions to Quaternary extinctions

        • Human predation

        • Habitat destruction

        • Hyperdisease hypothesis

        • Climate change

    • 1600s-present day

      • Available information improves from 1600 onwards

        • >1000 recorded extinctions (>half in last century)

      • IUCN 1994

        • More strigient extinction criteria

          • Extinct:

            • When there is no reasonable doubt that the last individual has died

          • Extinct in the wild

            • When exhaustive surveys in known/expected habitat, at appropriate times thoughout its historical range have failed to record an individual

        • The data about extinctions are likely underestimates as strong bias towards:

          • Higher plants/birds/mammals

          • Islands 

            • 71% mammal extinctions from islands

          • Terrestrial & freshwater

            •  (4 (5) extinct marine sp.)

          • Described species – most are not

      • More than 44,000 species threatened with extinction (2023-24) compared to 46,300 species this year (2024-25)

    • Future

      • Extinction debt – exploit past self-sustaining numbers

        • Species is effectively extinct – it just doesn’t know it yet!

          • Ex. Brooks & Balmford (1996)

            • Extinction debt in Atlantic forests of S. America

              • 90% of forest cleared – but, as yet, no significant loss of bird species.

      • Many species not yet extinct but suffering huge population losses

        • Ex. tropical forests 1,800 populations per hour (16,000,000 per yr)

        • Ex. land use change

          • Decline in global bird population to one quarter of pre-agricultural levels

  • Principal (proximate) causes

    • Overexploitation

      • Most obvious impact: hunt/exploit to last individual/viable pop.

        • Scale is difficult to comprehend and unsustainable

      • Examples

        • Bush meat

          • Hunting in tropical forests – places without exploitation do not exist

            • Ex. 9.6-23.5 million (67 000-165,000 tons) reptiles, birds, mammals per year in the Brazilian Amazon

          • Unsustainable

            • Ex. Mammal production rates

Location

Production rates (million tons/year)

Extraction rates

Body mass.y-1

                                 

Congo Basin

2.1

4.9

93%

Amazon Basin

1.8

0.15

4%


  • Firewood/fuelwood

    • Over 1/3 of humankind (2.8 billion), directly dependent solely on fuelwoods for energy

    • Despite treeplanting programmes woodfuel

    • demand 2.4-4.3 billion m3 

      • Present availability 2.3-2.4 billion m3 uelwood/charcoal

  • Marine fisheries

    • 1st major collapse: Peruvian anchoveta Engraulis ringens (1971-72)

    • Wider impacts:

      • Reorganisation of structure of remaining species

      • Incidental capture/killing of other species, ex. turtles, sea mammals)

      • Huge bycatch (>25 million tons/yr)

      • Habitat destruction 

        • Ex. bottom trawling, dynamite fishing

      • Environmental consequences of fishing debris

        • Ex. “ghost” nets

  • Habitat loss/degradation

    • Restructuring distribution of habitats or vegetation types– persistent feature of humankind

      • Often ‘natural’ landscapes are not!

    • Declines

      • Forest/woodland: 29%

      • Steppe/savannah/grassland: 49%

      • Shrubland: 74%

      • Hot/Ice desert: 14%

      • Cropland 11% 

      • Pasture 23%

    • Human disturbance in every biome

      • Most marked temperate broadleaf and evergreen forests <6.5% undisturbed

    • Land-use changes:

      • Species lost as predicted by species-area relationship

        • Ex. 71% freshwater fish that have become extinct

          • 85% birds

          • 47% mammals

      • Land-use also changing due to climate change

      • Bringing humans and wildlife into closer contact

  • Introduced/invasive species

    • Intentionally/unintentionally introduction of non-domesticated species

      • Earliest known incident

        • Introduction of marsupial Grey Cuscus to New Ireland (Papua New Guinea) 19,000 years ago

    • Approx. 400,000 species have been introduced.

      • 10% of introductions become established

      • 10% of established become pests

    • Negative effects can be large-one of the great historical convulsions in the world’s fauna and flora

    • Pests-major agents of global change; 50% of threatened species in US at risk due to alien species (mainly predation/parasitism)

      • Examples:

        • Nile perch in Egypt

          • Voracious predator

          • Caused extinction of endemic fish species from East African Rift Valley

        • Brown tree snake in Guam

          • Accidental introduction

          • Destroyed 12 (of 22) native bird & 5 (of 12) native reptiles 

          • Snake generalist predator so its numbers remain high

        • European rabbit

          • Original expansion caused by the Romans 

            • Iberian Peninsula → Italy for food

          • 1066: Normans to England

            • Age of exploration – invaded many small islands

          • 1859: Australia

            • Rich British landowner Thomas Austin

              • He missed the hunt so brought 24 rabbits to Victoria

        • Quagga mussel (Dreisena bugensis)

          • Found in River Wraysbury, London 1st Oct 2014

          • Ponto-Caspian species originally

    • Economic cost – vast 

      • Ex. 50,000 non-indigenous species  (USA) cost $137 billion in economic damage and control

    • Net effect of species extinctions/introductions:

      • Homogenize biotas across the globe – more similar.

        • Ex. on average pairs of states in continental US now  have 15.4 more fish in common than before European settlement

  • Extinction cascades

    • Extinction of one species leads to extinction of others

      • Examples:

        • New Zealand Giant eagles preyed on flightless moas →

          • Moa extinction by Maori hunting led to eagle demise

  • Ulitmate causes

    • All causes of extinction considered so far are proximate

    • Size of human population

      • 7.93 billion individuals (Feb 2022)

      • Animals and people show similar relationships with primary productivity, finding similar kinds of area good for multiplication

        • This relationship breaks down at high densities

    • Growth of human population

      • Population growth slow for most of human existence

        • Dramatic increase within the last 200 years

          • Population growing most rapidly in biodiversity hotspots

      • Human population growth & species extinction:

        • Epitomized by Silphion (herb in carrot family)

          • Anti-fertility drug from Cyrene (Libya)

          • Valuable commodity, principle trade item

            • Difficulties in cultivating led to overharvesting → extinct in the 2nd/3rd Century

    • Scale of human enterprise

      • Primary production

        • Use/destroy 35-40% total terrestrial primary production

        • 8% of aquatic primary production (disproportionately nearshore & freshwaters)

      • Energy use

        • From agricultural revolution to present:

          • Power consumption x> 10 k

        • Global commercial energy production >160 000 tetrawatts

      • Water (key resource)

        • Use 25% of total rainfall

        • Use 50% of total runoff

        • Where is it going?

          • 42% attributable to agriculture

          • 14% attributable to industry

      • Global Economy

        • Global increases in consumption outpace population increase

          •  Ex. 1980-97 former tripled latter increased by a third

        • Massive increase in resource usage due to economy growth


30 January 2025: Maintaining biodiversity


  • Intro to Convention for Biological Diversity (1992)

    • Took place in Rio

    • Binding global treaty

    • Conservation recognised as common concern for all humankind

    • 42 articles

    • Included genetic diversity

  • Objectives

    • Three main goals

      • Conservation of biological diversity

      • Sustainable use of its components

      • Equitable sharing of the benefits arising from the ultiization of genetic resources

        • Problem worse where developed nations exploit

        • Biodiversity of developing ones, but more widespread than this 

          • Ex. Fungus Tolypocladium inflatum – collected by biologist on holiday in Norway (1969)

            • Drugs ex. cycloporin A (immunosuppressant, essential in organ transplants) developed.

              • 2% royalties on sales – reasonable claim if benefit sharing with source country had been in operation – in 1997 $24.3 million

    • Only achieved through sustainable use

      • Only if benefits arising from the use are fairly/equitably distributed

  • Measures for conservation and sustainable use (Article 6)

    • Most far reaching/significant article

    • Measures not just expected to emerge somehow – nations obliged to develop and/or implement mechanisms

      • If they are to be effective – national plans & programmes will have to be integrated with policies in areas such as agriculture, education, employment, energy, health, industry, transport

        • They must become central to the way a nation’s affairs are conducted

        • National/local measures (UK)

          • 1994: UK Biodiversity Action Plan launched

          • 1995: UK Biodiversity Steering Group was created

          • 1997: “Action for biodiversity in the south west: a series of habitat and action plans to guide delivery”; started the biodiversity planning process in this area

          • 1998: “The Nature of Devon: A Biodiversity Action Plan” took the planning a stage further, Dartmoor National Park Authority and English Nature produced “The Nature of Dartmoor: A Biodiversity Profile”, The successful three year Dartmoor Biodiversity Project was launched

          • 2001: The Dartmoor Biodiversity Action Plan was produced; the Dartmoor Biodiversity Project launched in September

        • Example of type of things that need to change

          •  ‘Perverse subsidies’ = subsidies adverse (to environment/economy) in long run

            • Ex. support for fossil fuels  - (44%*)

              • Increase pollution, smog, global warming

            • Ex.  support for energy/fossil fuels –(27%)

              • Increase pollution, smog, global warming

            • Ex. road transport – (29%) 

              • Increase pollution, habitat destruction

          • Scale of perverse subsidies vast 

            • Energy costs: $4.9 trillion worldwide (2017)

              • Often exceeding the marketable value of the goods generated.

            • US citizens taxed $2000 per annum to fund perverse subsidies

              • Also pay same amount through increased costs of consumer goods/environmental degradation

    • In accordance with Article 6 many countries developed:

      • National Biodiversity Strategies (general policy instruments to identify strategic needs)

      • Biodiversity Action Plans (or BAPs) (practical documents that identify what is to be done and who is to do it), 

        • Ex. UK BAP (1994)

      • At best – identify ways in which societies operate can be restructured

        • More frequently – aspirations

          • Little indication of how met, fail to recognise fundamental nature of what must be done


  • Identification & monitoring

    • Gathering info to assess whether strategies/programmes/plans are appropriate and/or working effectively

    • Impossible to identify/monitor all facets of biodiversity so they placed emphasis on:

      • Components considered important for conservation/sustainable use

      • Activities likely to have significant impact on conservation/use

  • In situ conservation

    • Sections a & b: establishment of protected area systems/networks, central to national strategies

      • 1. Most areas are too small

        • Corridors would be improvement but rarely implemented

        • Overall number increases, but average size decreases with time

      • 2. Protected areas biased towards land with low economic value (also towards limits of geopolitical units – ‘buffer zones’)

        • Consequently do not represent patterns of natural occurrence

      • 3. Designated YES – protected NO; Many ‘paper parks’

        • Ex. Grønne Ejland, Greenland Protected, Ramsar Convention on Wetlands of International Importance 1987

          • Special ref – world’s largest colony of Arctic terns (1950’s 50-80 k breeding pairs)

            • Summer of 2000: not one pair

      • Cost comparison

        • Protected areas globally: $10 billion

          • Generate $600 billion in income

        • Replacement space shuttle: $2.1 billion

        • F-35 fighter plane programme $400 billion

          • Pentagon will invest further $1 trillion

        • Global weight loss & diet management products and services: $390.3 billion

      • 4. Overall extent of existing conservation network improving but still too small

        • IUCN (1993)

          •  10% raised to 17% land area of each nation

            • 10% ocean area

        • Balmford – global initiative 30% of oceans - $23 billion/yr + $6 billion/yr (over 30 years, start up)

        • Target now – 15%

          • Still too low

          • Marine environment;

            •  0.5% ocean area

    • Sections c, d & e: establishment of protected areas, not enough must also protect wider area as the areas are

      • Not isolated and most threats come from outside

        •  Ex. extinct rates in large African mammals in protected zones increases with increasing human density in surrounding area

          • Not closed

            • Ex. 80% African elephants live outside protected zones

      • Cost of preserving biodiversity beyond reserves

        • UN 1993: remediation in areas beyond reserves (per year)

          • Forestry: $34 billion

          • Freshwater: $1 billion

          • Coastal/marine: $14 billion

          • Farming: $240 billion

        • Still just a fraction of perverse subsidies

    • Section f: rehabilitation of degraded ecosystems

      • Birth of restoration ecology (1990’s)

    • Sections g & h: taking action against destructive introductions

      • Regulating, managing, controlling risks associated with modified (including GM) organisms

    • Sections i & j: look for ways of minimising conflicts between conservation & present use 

      • Recognizes that knowledge, innovations, practices of indigenous/local communities may be pertinent to conservation/sustainable use.

        • Cultural relevance promoted

    • Sections k, l & m: Mechanisms for conserving biodiversity-legal, financial etc.

      • Recognition that available resources are not evenly distributed – poorer countries will need support (recurrent theme)

      • Particularly important due to complex set of interactions between poverty and the environment

        • 1. Majority of biodiversity exists in nations with the least resources for conservation/sustainable use

        • 2. ‘It’s the poor that do the suffering’

          • Damage to ecosystems impacts most directly on the poor

            • Suffer the effects of polluted environments

            •  Suffer the loss of productive lands (incl. the sea)

            • Suffer the loss of traditional sources of food, fodder, fuel & fiber when forest cut down

        • 3. Inequalities across the board

          • Relative impacts of factors affecting biodiversity are not the same in poorer (a) and richer (b) countries

          • The poor do not have financial resources to acquire essential resources; money reduces vulnerability to local environmental degradation

  • Ex situ conservation

    • Can include:

      • Seed banks

      • Sperm and ova banks

      • Culture collections

        • Ex. plant tissues

      • Artifical propagation of plants

      • Captive breeding of animals

        • Growing trend: more individuals of some species in captivity than in wild

    • Costs/benefits for ex-situ conservation hotly debated:

      • Particularly for large-bodied vertebrates, ex. primates, big cats, cetaceans

      • Key issues:

        • Ethics around keeping large animals in captivity 

        • Short and long term viability of captive populations

          • Relationships between them, ex. reintroductions

        • Expensive: is it worth it?

        • Other benefits

          • Ex. urban education

  • Sustainable use

    • Strategies to live sustainably

    • Human exploitation estimated to be greater than Earth’s productivity

      • Ecological footprint x1.5-2.0 entire Earth (2020 figures)

    • Convention proposes integration into national planning 

      • Debate centred on appropriate approach to trade (free-market, highly regulated)

        • Requires support of local peoples

          • But widespread belief that primitive people ‘live in balance with nature’ → myth

        • Distortions of history

          • When not: appeal to traditional uses reflect situations with low human density/ no commercial exploitation

  • Incentive measures

    • Adopt economically and socially sound measures that act as incentives for conservation/sustainable use.

      • In reality, the converse is often true, ex.. perverse subsidies

  • Responses to the convention

    • A number of countries have produced strategies and Baps – easy part

      • Implementing changes is more difficult – unpalatable to politicians with short term goals

      • Need to establish & agree measurable goals – but has not been happening

        • Hence the frustration at World Summit on Sustainable Development, Johannesburg, 2002

          • World summit on Sustainable Development (Johannesburg Aug-Sept 2002)

            • 22,000 people participating, more NGOs and ordinary people than before

            • No new treaties – new targets

              • Halve proportion of people without access to basic sanitation by 2015

              •  Use/produce chemicals by 2020  in ways they do not negatively impact human health/environment

              • Maintain/restore depleted fish stocks by 2015

              • Significant reduction in current loss of biodiversity by 2010

        • Millennium Ecosystem Assessment Synthesis Report (2005)

          • 2/3 of world’s ecosystems destroyed or degraded

        • Sept 25th 2015 UN – 2030 Agenda for sustainable development (17 sustainable development goals, 169 targets)

          • 1 No poverty

          • 2 Zero hunger

          • 3 Good health and well-being (44% reduction in global maternal mortality)

          • 4 Quality education (92% complete primary, 74% complete lower secondary)

          • 5 Gender equality

          • 6 Clean water and sanitation (50% reduction in those with no access to improved water source)

          • 7 Affordable and clean energy

          • 8 Productive employment and economic growth

          • 9 Industry, innovation and infrastructure

          • 10 Reducing inequalities

          • 11 Sustainable cities and communities

          • 12 Responsible consumption & production

          • 13 Climate action

          • 14 Life below water

          • 15 Life on land

          • 16 Peace, justice and strong institutions

          • 17 Partnership for global development

        • Increase marine protected areas from 2% oceans (2014) to >10% by 2020

        • Aichi Targets (2011-2020)

          • Goal A: Address the underlying causes of biodiversity loss by mainstreaming biodiversity across gov’t and society

          • Goal B: Reduce the direct pressures on biodiversity and promote sustainable use

          • Goal C: Improve the status of biodiversity by safeguarding ecosystems, species, and genetic diversity 

          • Goal D: Enhance the benefits to all from biodiversity and ecosystem services

          • Goal E: Enhance implementation through particpaotry planning, knowledge management and capacity building

        • COP15 (2022) Montreal ‘Landmark UN Biodiversity Agreement’

          • 4 goals, 23 targets for 2030

            • Protect 30% of Earth’s lands, oceans, coastal areas, inland waters

            • Reduce by $500 billion annual harmful government subsidies

            • Cut food waste in half

        • COP15 (2023) Dubai

          • 1. Formally adopts climate loss and damage fund.

          • 2. Criticism : didn’t rein in climate changing emissions (no national targets to scale back fossil fuels)

        • COP16 (2024) Columbia

          • Formation of body for recognising a role of indigenous peoples in future conservation decisions

          • Levy on largenBiotech Companies (0.1% for using genetic resources, particularly from biodiversity hotspots

          • No agreement on funding roadmap for species protection (ran out of time – delegates left early and so summit not quorate to make decisions)

        • COP29 (Nov 2024) (Baku, Azerbaijan)

          • New finance goal to help countries to protect their population/economies against climate disasters, share in benefits of  clean energy boom

          • Triple finance to developing countries, from $100 to 300 billion annually by 2035.

          • Scale up finance to developing countries, from public and private sources, to $1.3 trillion annually by 2035