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Environmental Science ENSC 2800

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Title: Environmental Science ENSC 2800


1
Environmental Science ENSC 2800
  • Spring 2002
  • Class 11
  • Endangered Species in the
  • Bay Delta

2
Biodiversity - broader context
  • Biological diversity the variety of living
    things and their relationships to each other and
    interactions with the abiotic environment
  • Genetic (DNA within a species e.g. saltmarsh
    harvest mouse)
  • Species (No. different types of organisms in a
    given habitat e.g. a saltmarsh)
  • Habitat/ecosystem (No. of different habitats or
    ecosystems in a particular region e.g.
    Bay-Delta).
  • What is a species? Organisms that are similar
    enough genetically to produce viable offspring
    through reproduction.
  • Different species live in communities, which
    together with the abiotic elements of a region
    make up a habitat.

3
Endangered Species Terms
  • VULNERABLE - A species particularly at risk
    because of low or declining numbers or small
    range, but not a threatened species.
  • THREATENED SPECIES a species whose population
    is not yet low enough to be in immediate danger
    of extinction, but which certainly faces serious
    problems.
  • ENDANGERED SPECIES a species, plant or animal,
    that is in immediate danger of becoming extinct.
     
  • EXTINCT SPECIES an extinct species is one that
    is no longer living, anywhere in its former
    range.
  • EXTIRPATED SPECIES one that was formerly
    present in an area but has since disappeared from
    there (but still exists elsewhere).

4
Causes of biodiversity loss
  • According to the United Nations Environmental
    Programs Global Biodiversity Assessment, the
    four most important processes to date have been
  • Land use change
  • Over exploitation of species for human benefit
  • Introduction of alien species to a region
  • Pollution - both rapid and gradual forms (part of
    a concept known as biotic impoverishment)
  • All these major factors are clearly at work in
    the Bay-Delta apply to California and are
    contributing to the reduction in the size,
    diversity and distribution of a range of species
    in the region.
  • In the Bay-Delta we can add water resource
    over-exploitation as a major factor.

5
Forces for change
  • The forces for environmental change interact to
    place pressure on species principally through the
    complex actions of food-webs and reproductive
    cycles.
  • Species numbers decline due to a combination of
    increasing morbidity and mortality and lack of
    reproductive success.
  • Although it is hard to separate out the impacts
    of each, the most important cause of species
    endangerment in the Bay-Delta is probably habitat
    loss and fragmentation due to land use conversion
    the 95 reduction in wetlands.
  • Second place, because of the impact on water
    flows, riparian conditions, and groundwater
    levels, would probably be the damming and
    diversion of water.
  • Of somewhat lesser importance, but clearly a
    contributory factor tthroug biotic
    impoverishment, would be the introduction of
    invasive species predators and competitors
    and pollution.

6
California Biodiversity
  • According to an extensive inventory developed by
    Jones and Stokes (1987)
  • California is home to 748 species of vertebrate
    animals.
  • More than 550 species of birds have been recorded
    in the State.
  • Some 5,200 species of native plants grow within
    California.
  • About 40 of the freshwater fish, 30 of
    amphibians and 10 of mammals are endemic.
  • Roughly 1/3 of California plants do not occur
    outside the state.
  • There are judged to be around 380 distinct types
    of natural assemblages of plants and animals (we
    can call these habitats although the exact
    definition is often hard to pin down).
  • If the total plants and animals are thus around
    6,500, some 5 (close to 300) are legally classed
    as either threatened or endangered.
  • CA is second only to Hawaii in officially TE
    species.

7
Valuing CA Biodiversity
  • Habitats provide key environmental services.
  • Natural forests regulate watershed functions
    leading to cleaner, more regular runoff and
    recharge.
  • Riparian areas beneficially absorb the impact of
    floods.
  • Wetlands absorb and/or biodegrade toxic
    chemicals, organisms, etc. that would otherwise
    affect water quality and the aquatic food webs.
  • Urban wildland buffers moderate local climate and
    abate air and noise pollution effects.
  • Agricultural wildland buffers control pest
    numbers and dispersal and provide refugia for
    natural pollinators.
  • Habitats and native species have increasing
    aesthetic value the more we lose, the more
    valuable the remainder becomes!

8
Economic trade-offs.
  • Our modern biodiversity laws predominantly work
    by protecting individual species (listings)
    although in roundabout ways, they usually end up
    protecting habitat directly or indirectly.
  • For example, preserving the chinook salmon
    involves both protecting forested Sierra Nevada
    streams from physical alteration to permit
    spawning and releasing sufficient amounts of
    water to rivers to facilitate upstream migration
    to be able to spawn.
  • Both require the foregoing of benefits - from
    forest exploitation and the extractive use of
    released water respectively - that carry an
    economic price tag.

9
Does natural mean free?
  • Nature provides its biodiversity values for free
    - no one pays mother earth.
  • However, preservation of natural resources has an
    opportunity cost, related to resource benefits
    that could accrue from habitat land, or whats
    under or above it, and from species themselves.
  • The opportunity cost is what has to be given up
    by not using nature in an alternative way.
  • Natural resources management also brings costs -
    e.g. the costs of managing a wilderness as such.
  • These are traded against natural resources
    benefits - both actual revenues (e.g. from
    tourism) or avoided costs (e.g. for water
    treatment, flood damage and repair).
  • These need to be compared against the costs and
    benefits of the alternatives to establish
    so-called net benefits to society.

10
Endangered Species Legislation
  • The California Endangered Species Act of 1970
    (CESA) parallels the main provisions of the
    Federal ESA (1973) and is administered by the CA
    Dept. of Fish and Game.
  • Under CESA the term "endangered species" is
    defined as a species of plant, fish, or wildlife
    which is "in serious danger of becoming extinct
    throughout all, or a significant portion of its
    range" and is limited to species or subspecies
    native to California.
  • CESA establishes a petitioning process for the
    listing of threatened or endangered species.
  • CESA prohibits the "taking" of listed species and
    applies to candidate species also (those being
    considered for listing).
  • State law defines "take" as "hunt, pursue, catch,
    capture, or kill, or attempt to hunt, pursue,
    catch, capture, or kill.
  • Species also found in other states may not be
    protected under CESA but nevertheless have
    federal protection under ESA.

11
Protecting Habitat?
  • State and federal laws are full of confusing
    contradictions and loopholes when it comes to
    habitat.
  • In California, state agencies are required to
    consult with DFG to ensure that any action taken
    on projects is not likely to jeopardize the
    continued existence of any endangered or
    threatened species or result in destruction or
    adverse modification of essential habitat.
  • However, according to legal experts, the
    selectively worded definition of take has not yet
    been interpreted by state courts to include harm
    to habitat.
  • The closest to this was a ruling against an
    irrigation district because its pumps sucked in
    too much water, diverting flows and killing
    endangered winter-run chinook salmon as a
    consequence.

12
Protected at any cost?
  • The state ESA allows limited takings of
    endangered (ES), threatened (TS) or candidate
    species (CS) for scientific, educational, or
    management purposes and of fish for sport.
  • Where projects must be reviewed under the CEQA
    environmental impact requirements, DFG are
    required to determine if they will place an ES,
    TS or CS in jeopardy directly or through habitat
    modification, directly or incidentally.
  • DFG must thus recommend reasonable and prudent
    measures to conserve the species to prevent any
    direct jeopardy or minimize the adverse impacts
    of the incidental jeopardy.
  • Thus incidental takings are in theory allowed
    by the state law a big source of disagreement
    with environmentalists.

13
Reasonable and prudent
  • The CA DFG is permitted to allow ES, TS or CS
    populations to be adversely affected (but not
    driven to extinction) if specific economic,
    social or other conditions make proposed
    alternatives infeasible.
  • The same is true at the Federal level where the
    ESA created the so-called God-Squad (ES
    committee) which decides, using cost-benefit
    concepts, whether a species should be allowed to
    be adversely affected by projects with federal
    oversight.
  • The god-squad has allowed at least three major
    exceptions to activities known to have placed TS
    ES in danger dam building on the Laramie and
    Little Tennessee Rivers, and logging in Pacific
    NW old-growth forests.

14
Biodiversity Preservation
  • There are many ways we can preserve biodiversity,
    from ex-situ (zoos, gene banks, etc.) to in-situ
    (bioreserves, protected habitat, balanced
    ecosystems).
  • In-situ programs are the ecologists preference
    and will vary according to the degree that human
    systems are integrated into or excluded from the
    process.
  • Many of Californias degraded habitats are
    hodge-podges of federal, state and private lands
    and our political and economic climate requires
    pragmatism.
  • Species recovery and preservation is, to the
    degree possible, conducted so that economic
    exploitation of land and resources can continue
    at a given level.

15
Biodiversity recovery plans
  • Recovery is the process by which the decline in
    an endangered or threatened species is arrested
    or reversed and threats to its survival are
    neutralized so that its long-term survival in
    nature is ensured (US FWS 1995).
  • The goal of the process is the maintenance of
    secure,self-sustaining wild populations with
    minimum necessary investment of resources.
  • A recovery plan delineates, justifies, and
    schedules the research and management actions
    necessary to support recovery of a species.
  • It provides a blueprint for assessing specific
    Habitat Conservation Plans developed under
    Federal legislation.

16
Biodiversity in the Bay-Delta
  • The Status and Trends Report for Wildlife of the
    San Francisco Bay Estuary (SFEP 1992) lists over
    380 terrestrial vertebrates amphibians,
    reptiles, birds and mammals associated with the
    Bay in the counties immediately adjacent to the
    Bay and Delta.
  • At least 10 vertebrates have been extirpated from
    the region,including sea otters, pronghorn
    antelope, elk and California condors. Two
    species, the grizzly bear and grey wolf, have
    been eliminated from the entire state (SFEP
    2000).
  • Some 52 different native fish species exist in
    the Bay-Delta, some 25 in the freshwater creeks
    and streams draining into the Bay-Delta.
  • (As yet, I have not tracked down the total number
    of plants or insect species that are native to
    the Bay-Delta if and when I do, Ill let you
    know!)
  • As of the last survey (1992), SFEP listed 150
    wildlife, insect and plant species as being of
    special status, extirpated or extinct in the San
    Francisco Estuary area. Some 90 of these are
    listed at the Federal /or State level as of
    concern, candidate, threatened or endangered.

17
Can we restore the Bay-Delta?
  • Rehabilitation of Endangered, Threatened and
    Candidate species in the Bay-Delta requires
    changes in the way we manage the estuary and its
    watersheds.
  • Because of the extensive establishment of
    nonnative species and massive changes to the
    region's land and water uses, many of them
    irreversible, restoration of the original
    ecosystems and habitats is really not possible.
  • It should nevertheless be possible to manage the
    system within the existing framework of change in
    ways that favor the development of naturalized
    ecosystems that are dominated by native species
    and that resemble the original systems in many of
    their ecological and aesthetic attributes.
  • Thus it should be possible for much of current
    resource system to coexist with relatively robust
    and functioning ecological communities kept in a
    balanced state by carefully monitored process
    environments that encourage their survival and
    reproduction.

18
Anadromous fishes
  • The Bay-Delta is both a lifeline and a bottleneck
    in the life-cycle of the Central Valleys
    anadromous fishes, especially the Chinook salmon.
  • Central Valley salmon occur in four discrete runs
    winter-run, spring-run, fall-run and late
    fall-run (run refers to the season in which
    adults return to their native streams to spawn
    SFEP-2000).
  • The winter-run Chinook,with the lowest
    population,has been listed as both a state and
    federal endangered species since 1994 (down to an
    historic low of 841 in 1997).
  • The next most sensitive stock,the spring-run,was
    state listed as a threatened species in 1998 and
    federally listed in 1999 (a five-year low of
    5,312 was recorded in 1997).
  • The fall-run are the most abundant, with 308,674
    returning in 1999 to the Sacramento and 24,459 to
    the San Joaquin.
  • Back before the Gold Rush, one to two million
    salmon would swim through the Delta on their way
    to spawn each year.

19
Restoring migrating fishes
  • No single restoration and protection measure will
    work since the fish are vulnerable at all of
    their life cycle stages, for different reasons.
  • Effort needs to be addressed at helping adults
    navigate the Delta (creating appropriate flow
    conditions, water quality, and prevention of
    entrainment in pumps).
  • Adults need help in surviving the swim upstream
    to spawning grounds (reducing predators, limiting
    fishing and bypassing obstacles).
  • Successful reproduction requires that there are
    appropriate conditions for spawning, egg hatching
    and fry survival (good substrate conditions,
    adequate refugia and good water quality).
  • Finally, juveniles (smolts) require the same
    treatment as their parents to allow their
    successful return back to the ocean, plus they
    need to survive the next three years or so (a
    little luck and some appropriate limits on
    commercial/sport fishing!).

20
Saltmarsh Harvest Mouse
  • A federally and state listed endangered endemic
    species of which less than 2,000 are thought to
    remain in the saltmarshes bordering the San
    Francisco Bay.
  • One of the more unique mammals because it can
    drink salt water and eat plants that are
    halophytic (can live in saltwater and salty
    soils).
  • Over 80 of its original habitat is gone and the
    remaining 20 is at risk from development or
    changes that will cause the saltmarsh vegetation
    to die out.
  • Recovery requires protection and selective
    replacement of this ecosystem around the Bay
  • Of particular importance for survival is also the
    preservation and enhancement of adjacent riparian
    high tide escape zones and ecotonal buffer areas
    to offer refugia in floods and to prevent
    predation by foxes, feral cats, etc (we are
    realizing this for other species too e.g.
    Red-legged frogs in the freshwater marshes).
  • Simply putting a line around the pickleweed
    marshes and assuming that the mouse will be
    protected has proven ecologically insufficient.

21
California Red-legged Frog
  • Made famous by Mark Twain and a favorite gourmet
    food item at the turn of the 19th/20th century.
  • Breeds in permanent water but migrates up to
    several miles between riparian woodlands over
    intervening terrain.
  • Reductions in wetlands reducing breeding grounds
    and reproductive success and fragmentation of
    habitat with land uses that lead to high
    mortality between breeding seasons have severely
    impacted population levels.
  • Other factors include pollution, 50 different
    invasive predators (e.g. mosquito fish,
    bullfrogs), modified water flows, impacts of
    cattle and proliferation of non-native
    vegetation.
  • Listed as Federal ES in 1996 and some 5 m acres
    in California were dedicated critical habitat
    and subject to environmental review less than
    25 of its historical range.
  • Subject to restoration efforts, principally
    through habitat restoration (wetlands, water
    conditions salinity, depth and temp., predator
    removal, creation of dense veg. and corridors,
    etc.) and reintroduction.

22
Readings From Merchant
  • To compliment these classes on biodiversity
    issues, please read the short essays and articles
    in Merchant beginning on pages 125, 162, 185,
    189, 194, 227, 287, 293, 312, 406, 423.
  • Also consult the State of the Estuary 2000 report
    (.pdf) posted on posted materials.
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