Environmental Science ENSC 2800

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Environmental Science ENSC 2800

• Spring 2002
• Class 11
• Endangered Species in the
• Bay Delta

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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.

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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).

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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.

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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.

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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.

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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!

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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!).

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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.

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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.

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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.