Transcript Why Conserve Invertebrates?

Ecology and Conservation of
Invertebrates
• Unique aspects of the ecology of
invertebrates
• Issues in the conservation of invertebrates
Invertebrate Ecology
• Predominance of complex lifecycles where
juvenile forms differ morphologically and
ecologically from adult forms
• Presence of eruptive dynamics
• Role in decomposition
• Role as parasites
Consequences of complex life
cycles in Invertebrates
• Processes affecting dynamics of juveniles may
differ and be unrelated to those affecting dynamics
of adult populations
• Juveniles and adult do not compete for the same
food resources
• Juvenile and adult forms may be specialized for a
limited set of functions, such a feeding, dispersal,
and/or reproduction
• Most species tend to be highly fecund, but
juvenile survival rates are low
Eruptive Dynamics
African Plague Locust –
Schisotcerca gregaria
Locust Plagues
(Insecta: Orthoptera)
March 2004
Cameraria hamdryadella
Dynamics of Cameraria hamadryadella
(Lepidoptera: Gracillariidae)
A. First Generation
B. Second Generation
1000
mines per leaf
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1
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Oak Grove
SW Woodland
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Invertebrate Parasites
• Platyhelminthes (flukes and tapeworms)
• Nematoda (roundworms)
• Arthropoda (lice, ticks, botflies, blowflies,
etc.)
• Nematomorpha (horse hair worms)
Role of Invertebrates in
Decomposition
• The decomposition of dead plant, animal tissues,
and fecal matter is accelerated by the activity of
invertebrates
• By physically assisting in the break-up of plant
and animal tissues, increasing surface area for
bacterial and fungal activity
• By ingestion and digestion of plant and animal
tissues or feces
• Widespread in marine, freshwater, and terrestrial
environments involving members of most phyla
Why Conserve Invertebrates?
• Speciesist arguments that they have a right
to existence
• Aesthetically pleasing
• Legally mandated
• Provide valuable Ecosystem Services
• Are a resource for human use (food,
biochemicals, jewelery, etc.)
Right to Existence
• Some ethicists argue that not only
individuals, but also species have a right to
existence
• Other ethicists claim that all rights are
vested in individuals, not in larger aggregate
entities like species or other taxonomic
categories
Aesthetically Pleasing
• Most humans find butterflies and some other
invertebrates aesthetically pleasing (scarab beetles,
corals, anything else?)
• However, most invertebrate groups do not have
the charismatic appeal of birds and mammals
• Most humans see invertebrates more as vermin
and as threats than as attractive and worthy of
conservation efforts
Legally Mandated
• Endangered Species Act or USA and
California
• International Prohibitions on Trade and
Transport
Ecosystem Services
Ecosystem services are the essential
functions of ecosystems that are carried
out via the activities of plant or animal
groups.
For example, plants function as
primary producers fixing carbon and
energy using CO2 and sunlight.
Ecosystem Services provided
by Invertebrates
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Pollination
Seed dispersal
Natural enemies of other pests
Decomposition
Soil formation
Invertebrates as a Resource
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Source of food for humans
Bait for fishing
Sponges for bathing
Corals, Conchs, Oysters and others for jewelry
Cloth production (silk)
Bees as pollinators of crops
Wasps, beetles, mantids, spiders, for biocontrol
Medicinal use of leeches
Target of bio-prospecting
Invertebrates as Food
• Mollusca (squid, mussels, clams, oysters,
scallops, snails, abalone)
• Crustacea (shrimp, lobsters, crabs, spider crabs)
• Insecta (beetles, ants, termites, grasshoppers,
bees)
• Echinodermata (sea cucumbers, sea urchins)
• Cnidaria (jellyfish)
• Annelida (palolo worms)
Bait for Fishing
• Earthworms (Oligochaeta)
• Insect larvae (Neuroptera – night crawlers)
• Shrimp, etc.
Sponges
• Collecting and use of about 12 species of
sponges continues since they are considered
of higher quality than synthetic sponges
Invertebrate used in Jewelry
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Morpho butterflies
Scarab beetles
Rare corals
Oysters and Conchs for pearl and mother of
pearl
Silk production
• Silk moth Bombyx mori
Commercial Pollination
Services
• Honey bees are mass produced and
transported to farms during flowering
periods to insure adequate pollination of
crop plants
• Without pollination fruits and vegetables
from insect pollinated crops will not be
produced
Biological Control Agents
• Insects and other invertebrates are being
used in biological control
• In agriculture, inundative release of
invertebrate predators or parasites are used
to suppress crop pests
• In forestry and range management, classical
biological control used to suppress pest
weeds
Medicinal use of Leeches
• Medicinal leeches are still used to
reduce bruising and scarring after
surgery
Target of Bio-prospecting
• Invertebrates could serve as a source of
biochemicals useful in medicine and other
applications
Pharmacologically active
Compounds from Invertebrates
• Ecteinascidin – from tunicates – tested for treatment of breast
and ovarian cancers
• Topsentin – from sponges – anti-inflammatory
• Lasonolide – from sponge (Forcepia sp). – anti-tumor
• Discodermalide – from sponges (Discomermia) – anti-tumor
Bryostatin – from Bryozoan (Bugula neritina) – anti cancer
• Pseudopterosins – from octocoral (Pseudoterogorgia
elisabethae) – anti-infammatory and analgesic agents that reduce
swelling and skin irritation
• Omega Conotoxin MVIIA – extracted from cone snails
(Conus magnus) – potent pain killer
Threats to Invertebrate
Conservation
Aquatic Environments
Terrestrial Environments
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Consumption
By catch
Habitat destruction
Pollution
Introduced species
Habitat destruction
Introduced species
Pollution
Consumption
Ornithoptera alexandrae
Male
Female (wing span 30 cm )
Collecting and habitat destruction for Oil Palm plantations in PNG
Maculinea arion
• Declined from over 100,000
individuals between 19521972
• Went extinct in England 1979
even in nature preserves
design for its protection
• Feeds on flowers of Thymus
in early larval stages
• Commensal in the nests of
an ant, Myrmica sabuleti, in
later larval stages
• Reduction in sheep and
rabbit grazing altered
microclimate near ground
and M. sabultei was replaced
by M. scabrinodes
• M. scabrinodes not a
adequate host for M. arion
• Now successfully reestablished after modifying
grazing regime
Maculinea arion
Wetas – Deinacrida sp. (Insecta: Orthoptera)
• Large ground dwelling cricket-like insects in New
Zealand
• Many species only persist on small islands where
introduced predators (rats, mice, and cats) are
absent
• Persistence of mainland populations requires
establishment of predator free reserves
• Habitat destruction also contributed to declines
Hemideina thoracica
Auckland Tree Weta
Photo by John Wattie
Distribution of Giant Wetas in New
Zealand
Medicinal Leech – Hirudo medicinalis
• Used for blood letting since the 5th century BC
• Still used to reduce bruising and scarring after
surgery and contains important anti-coagulant
compounds
• Intense collecting and habitat loss in Europe
where it is native led to severe decline and its
listing as threatened by the IUCN
• Captive breeding now being used in place of wild
caught animals
Noble Crayfish
Astacus astacus – noble crayfish
(Crustacea) – IUCN endangered
• Formerly abundant European Crayfish
• Pollution (DDT and lake acidification)
• Fungal disease introduced from North
America
• Competition with introduced crayfish
• Size based catch limitation and attempts to
stop disease spread
Extinct Insects in the Bay Area
• First recorded extinction of a native US
insect Satyr butterfly (Cercyonis sthenele
sthenele (19th century)
• Pheres Blue butterfly (Icaricia icaroides
pheres) and Xerces blue (Glaucopsyche
xerces) extinct in 20th century
• Antioch dune shield back katydid (Neduba
extincta), extinct before it was described
from a single museum specimen
Endangered Insects in the Bay
Area
Lepidoptera Lange’s metalmark Apodemia mormo langei
San Bruno elfin
Incisalia mossii bayensis
Behren’s silverspot Speyeria zene behrensii
Mission blue
Icaricia incaroides missionensis
Callippe silverspot Speyeria callippe callippe
Myrtle’s silverspot Speyeria zene myrtleae
Coleoptera
Bay checkerspot
Euphydryas editha bayensis
Delta green beetle
Elaphrus viridis
Insect Conservation in the Bay Area
• Hard to know what species were here before extensive human
settlement
• Of the pinned insect collection in the CAS, 248,565 specimens
represent 8,668 species and sub-species
• West Germany has 9,694 species and is 13.9 times larger than
the 9 county region
• CAS estimate an underestimate
• Recent sampling of bees in Napa and Sonoma counties
recorded 17 and 10 species respectively, that are not in the CAS
collection
San Francisco butterflies and insects
• 46 species of butterflies native to San Francisco
• Only 26 species have been observed in the last 15 years
• 3 species are known to be extinct, but the other species
occur in other counties
• Given that only 14% of the land area of San Francisco is in
parks, we would predict using the species-area relationship
that 18 species should have been lost from San Francisco,
but about 20 have been
• So about 6.5% of the insects native to San Francisco are
possibly extinct and 43% are no longer found in there , but
persist in adjacent counties
Introduced Species - Snails
• Giant African snail Achatina fulica – dispersed by
people for food, but became a crop pest
• Euglandina rosea was introduced on various
Pacific islands to control Achatina
• Euglandina has caused the extinction of native
snails on Morrea in the genus Partula, and has
been sown to prey on aquatic species as well
Giant African Snail
Euglandina rosea
Introduced Invertebrates in
California
• 177 species of insects invaded California
between 1955 and 1988 (5 species/year)
• Over 200 species of invertebrates have
invaded San Francisco Bay and in some
areas of the Bay account for 95% of the
biomass
Summary
• Ecology of invertebrates highly diverse
• Growing number of invertebrate species are
endangered or threatened by human
activities
• Invertebrates are valuable resources for
humans, but our ignorance of their biology
and distribution hamper conservation