Protecting Endangered Wildlife

1
Protecting Endangered Wildlife
2
Endangered species

• Federal legislation (not states)
• Endangered Species Act
• Endangered species in U.S. and World

3
Federal Programs for Wildlife Protection

• Lacey Act (1900 amended 1976)
• Prohibited the transportation of illegally killed
  game across state lines
• curbed trafficking in bird feathers
• only mandated fines
• amendments increased fines up to 10,000

4
Federal Programs for Wildlife Protection

• Migratory Bird Treaty Act (1918)
• Canada and Mexico
• Gave international recognition to migratory
  birds.
• Each country issued regulations provided
  policing powers for their enforcement.

5
Federal Programs for Wildlife Protection

• 1949. Establishment of the National Wildlife
  Refuge System.

6
Convention on International Trade in Endangered
Species (CITES)

• International agreement of the early 1970s to
  curtail international trade in endangered
  species.
• Signatories (currently 160 countries) meet every
  2-3 years
• Species listed according to vulnerability3
  appendices

7
Convention on International Trade in Endangered
Species (CITES)

• Appendix 1 species endangered by trade
• Appendix II species that are or may become
  threatened by trade
• Appendix III species that, in the view of a
  member nation, should be subject to regulation
  within the nation as a means of conservation

8
World Trade In Wildlife and Wildlife Products

• Has led to numerous rapid population declines of
  many species

9
Annual World Trade in Selected Wildlife Plants
Product At least Primates (live)
40,000 Birds (live) 3,000,000 Ornamental fish
350,000,000 Furs
40,000,000 Reptile skins
20,000,000 Reptiles (live)
100,000,000 Coral (raw) 1,000
tons Cacti 10,000,000 Orchids
2,000,000 From Henley,G 1995. Wildl. Soc. Bull
23 635-639
10
Legislative Response to Endangerment

• Endangered Species Conservation Act of 1966
• Habitat acquisition
• Endangered Species Conservation Act of 1969
• Started process that led to CITES
• Endangered Species Act of 1973
• amended 1978, 1982, 1988

11
ESA of 1973

• Basic Intent and Purpose
• to provide a means whereby the ecosystems upon
  which endangered species and threatened species
  depend may be conserved, to provide a program for
  the conservation of such endangered species and
  threatened species, and to take such steps as may
  be appropriate to achieve the purposes of the
  treaties and conventions set forth in subsection
  (a) of this section
• a law that plays in when local planning and
  zoning, state fish and wildlife efforts, the
  Clean Water Act, and Clean Air Act havent
  worked. It is the emergency room of conservation
  policy (M. Beattie 1995)

12
Endangered Species Act

• Extended coverage to plants as well as animals
• Recognized endangered species as components of
  ecosystems stressed that integrity of the
  ecosystems must be maintained
• Distinctions made between threatened endangered

13
The Endangered Species Act

• How a species is Classified
• And What Steps are Taken for its Conservation
• Petition Process
• Listing (T or E)
• Recovery Team
• Recovery Plan
• Critical habitat (?)
• Implement Recovery Plan
• Monitor populations
• Re-classify or de-list

14
Current List of Threatened Endangered Species
15
Patterns of Endangerment in US(Dobson et al.
1997)
PLANTS
16
Patterns of Endangerment in US(Dobson et al.
1997)
Fish
17
Pallid Sturgeon

• Once found from Montana (Missouri River) to
  Louisiana (Mississippi)

Over 80 lbs. and six feet long Habitat change
along rivers has contributed to decline On
endangered list
18
Patterns of Endangerment in US(Dobson et al.
1997)
BIRDS
19
Funds Spent on Threatened/Endangered Species
1989-1991
1. Bald Eagle 31,000,000 2. No. Spotted Owl
26,000,000 3. Florida Scrub Jay
19,900,000 4. West Indian Manatee
17,300,000 5. Red-cockaded Woodpecker
15,100,000 6. Florida Panther 13,600,000 7.
Grizzly Bear 12,600,000 8. Least Bells
Vireo 12,500,000 9. Amer. Peregrine Falcon
11,600,000 10. Whooping Crane
10,800,000 Source Metrick-Weltzman, Harvard
Univ. as quoted by R. Barro, Wall Street Journal,
Aug 14, 1994
20
Funding of endangered species versus priority
rank (Restani and Marzluff 2002)
21
Funding of endangered species versus priority
rank (Restani and Marzluff 2002)

• Underfunded tend to be reptiles, amphibians, and
  small mammals or birds
• Overfunded tend to be larger birds and mammals,
  especially carnivores

22
Classification

• How unique?
• What is the risk (high/moderate/low)?
• Is the threat imminent or not?

23
Classifying Endangerment

• Listing species is first step toward conservation
  
• During listing they are classified as
  Endangered or Threatened
• endangered- any species which is in danger of
  extinction throughout all or a significant
  portion of its range
• threatened- any species which is likely to
  become an endangered species within the
  foreseeable future throughout all or a
  significant portion of its range

24
What are TE Functionally?

• Wilcove et al. (1993) reviewed characteristics of
  listed species
• Endangered animals (median values)
• 515 individuals, 1-5 populations
• Endangered plants (medians)
• 99 individuals, 3 populations
• Threatened animals
• 4161 individuals, 1-5 populations
• Threatened plants
• 2499 individuals, 9 populations

25
IUCN Categories

• Much more biologically based (Mace and Lande 1991
  and updates)
• Extinct
• Extinct in the wild
• Threatened
• Critically Endangered
• Endangered
• Vulnerable
• Lower Risk
• Conservation Dependent
• Near Threatened
• Least Concern

26
Threatened IUCN Categories

• Critically Endangered extreme risk of extinction
  in the wild in the immediate future
• 80 reduction in last 10 years (or 3 generations
  whichever is longer)
• occurs over
• declining or
• at least 50 chance of extinction in 10 years (or
  3 generations whichever is longer)

27
Threatened IUCN Categories

• Endangered high risk of extinction in the wild
  in the near future
• 50 reduction in last 10 years (or 3 generations
  whichever is longer)
• occurs over
• declining or
  population
• at least 20 chance of extinction in 20 years (or
  5 generations whichever is longer)

28
Threatened IUCN Categories

• Vulnerable high risk of extinction in the wild
  in the medium-term future
• 20 reduction in last 10 years (or 3 generations
  whichever is longer)
• occurs over
• declining or
  population
• at least 10 chance of extinction in 100 years

29
ESA vs IUCN categories

• Wilcove et al.s analysis suggests that listed
  species in US under ESA are in two most critical
  classes of IUCN categorization
• low number of indivduals (populations
• emphasizes that the ESA is REACTIVE not proactive
  and shows why many species do not recover after
  listing--theyre too far gone already

30
But, What Do We Mean by Species?

• ESA and CITES define species as any subspecies
  of fish or wildlife or plants, and any distinct
  population segment of any species of vertebrate
  fish or wildlife which interbreeds when mature
• plant populations do not get special
  consideration
• NMFS often lists fish stocks (local
  non-interbreeding populations)

31
What is Actually Listed?

• Wilcove et al.s Analysis suggested that most
  listed species were full species
• only 20 of listed species were subspecies or
  populations, but this varied by taxonomic group
• birds---80 of listed species were subspecies
  or populations
• mammals--70 of listed species were subspecies
  or populations
• Mollusks--5of listed species were subspecies
  or populations
• Plants--14 of listed species were subspecies
  or populations

32
Proactive or Reactive?

• Seems the ESA is proactive for birds and mammals,
  but reactive for plants and inverts based on the
  type of unit that is listed.

33
Administration of the Act

• Done by US Fish and Wildlife Service or National
  Marine Fisheries Service
• Two main thrusts
• LISTING
• RECOVERY

34
Listing

• Initiated by petition (individual, group, agency)
  or Service uses its priority system and available
  biological information
• Priority system for listing

35
Recovery

• Outline of recovery actions needed within 60 days
• Recovery Plans developed by Recovery Team for the
  Regional Manager
• Prioritization of species (add C for conflict)

36
ESA Provisions

• Limit any person subject to jurisdiction of US to
  take endangered species (harass, harm, pursue,
  hunt, shoot, wound, kill, trap, capture, or
  collect, or to attempt to engage in such conduct)
• Harm was later defined and upheld by Supreme
  Court (1995 Babbitt vs. Sweet Home Chapter of
  Communities for a Great Oregon) to include
  HABITAT MODIFICATION

37
Designating Critical Habitat

• Critical Habitat includes habitat in and out of
  current range that contains physical or
  biological features (1) essential to the
  conservation of the species and (2) requiring
  special management considerations or protection.
• Federal agencies must not jeopardize listed
  species or appreciably affect their abundance by
  reducing or modifying their critical habitat
  (Sect. 7)
• Required to be designated at time of listing
• if PRUDENT and considering economics
• USFWS rarely sees it as prudent anymore

38
Incidental Take

• Incidental take is take that results from some
  activity but is not the purpose of the otherwise
  lawful activity.
• Can take species only with permit
• Federal agencies get incidental take statement
  in biological opinion by USFWS
• Private and state entities get incidental take
  permit by negotiating a habitat conservation
  plan (HCP)

39
Mitigation for Take

• Basically incidental take is allowed if it is
• minimized and will not appreciably reduce the
  likelihood of survival and recovery of species
• mitigated
• defined as to extent
• monitored
• all alternatives are impractical
• applicant ensures funding and means to deal with
  unexpected circumstances

40
Getting off the List

• Priority system for de-listing and down-listing
  as well
• based on petition status and the impact of the
  reclassification on other management (how much
  will be freed up to do other work)

41
Enforcement and Penalty

• Citizen suits---backbone of the act
• can sue individuals, corporations, or agencies
• Penalties depend on status of species, knowledge
  of violator
• knowing violators can get 1 year in prison and
  50,000 fine (half of both for threatened
  species)
• can revoke leases, licenses, etc.
• equipment can be forfeited

42
Is the Current ESA Working?

• Recovery Plans have been required since 1978
• Plans goals are to restore the listed species to
  a point where they are viable, self-sustaining
  components of their ecosystems
• Tear et al. (1993) reviewed 54 plans on T E
  species filed up to that time

43
Are Recovery Plans Adequate? (Tear et al. 1993)

• 28 had recovery goals calling for populations of
  smaller size than current
• 37 called for fewer populations than present
• 60 had goals below that which Mace and Lande
  (IUCN) used to define endangered
• So, we seem to be managing species to extinction,
  not recovery

44
Alternative Ways to Score ESA Effectiveness
(Noecker 1998)

• Are species recovered to level where protection
  is no longer required?
• NO, only 11 have been delisted due to recovery
• Brown Pelican, Palau fantail flycatcher, Palau
  ground-dove, Palau owl, American alligator,
  Rydberg milk-vetch, Gray whale, Arctic peregrine,
  3 species of kangaroos,
• reasons for endangerment (2DDT, 3 WWII, 5
  overharvest, 1 questionable data)
• 7 went extinct and 9 were delisted due to new or
  improved data

45
Alternative Ways to Score ESA Effectiveness
(Noecker 1998)

• Have populations of listed species become more
  stable since listing?
• Maybe (estimate 41 of 1676 species have improved
  or stabilized)
• 22 species originally listed as endangered have
  been downlisted to threatened (2 eventually were
  delisted Arctic Peregrine and American alligator)

46
Alternative Ways to Score ESA Effectiveness
(Noecker 1998)

• Has listing prevented extinction?
• YES, only 7 of the 1676 listed species have gone
  extinct
• 5 of these were actually extinct at time of
  listing!
• Condor, Red Wolf, Whooping Crane would likely be
  extinct without the Act

47
Does the ESA protect Ecosystems? (NRC 1995)

• Difficult to tell--most emphasis is on single
  species
• Of 411 recovery plans, 25 include multiple
  species
• some cover full communities (Ash Meadows,
  Maui-Molokai birds, Channel Islands)
• Even single species plans can protect ecosystems
• spotted owl, murrelet may protect old-growth

48
Constraints on Endangered Species Management
Political Considerations
Limited Breeding Population
Endangered Species Management
Land Use
Limited Habitat
Competition With Other Wildlife And People
Biological Knowledge
Legal Constraints
49
Critical Habitat Designation

• At listing (after 1978, not retroactive)
• Takes into account ECONOMIC impacts
• Can be opted out if non prudent or not
  determinable
• non-prudent can be for any reason
• To date designated (NRC)

50
Habitat Conservation Plans

• More likely to be the way habitat is protected on
  non-federal lands (rather than designation of
  critical habitat)
• Allows non-federal landowners to get incidental
  take permit
• implementation of HCP will, to the maximum
  extent practicable, minimize and mitigate the
  impacts of such taking and not appreciably
  reduce the likelihood of survival and recovery of
  the species in the wild

51
HCPs as a Solution to a Problem

• Services view HCPs as a way to balance a
  citizens right to use their property with the
  nations interest in conserving rare and
  endangered species
• Goal is to create creative partnerships between
  landowners wanting to develop their land and our
  natural heritage
• No surprises means that once agreed to, if
  landowner follows HCP then agencies wont add new
  requirements in future

52
Increase in HCPs

• San Bruno Mtn. Cal (1983)
• Over 200 in 1997, 200 more in preparation
• Range in size
• 1/2 acre lot (Fl. Scrub Jay)
• 170,000 acres
• Plum Creek Timber (WA)
• 100 years, 285 listed and unlisted species
• 1.6 million acres
• WA Dept. Nat. Resources
• 70-100 years, 200 species

53
The HCP Process (USFWS 1998)

• Plan Development
• permit application (25)
• the plan
• document of compliance with NEPA (National
  Environmental Policy Act)
• implementation agreement
• Review
• service
• public (published in Federal Register)
• Monitoring
• service monitors compliance with HCP

54
Contents of HCP (USFWS 1998)

• Species covered (listed and non-listed)
• Assessment of impacts of take
• How take will be monitored, minimized, and
  mitigated
• Plan for funding the proposed monitoring and
  mitigation
• Alternatives to take and why they are not being
  adopted
• Argument that taking will not reduce the species
  survival and recovery

55
Criticisms of HCPs (Minett Cullinan 1997
Kaiser 1997)

• Not based on science
• We need to know a lot about management of species
  to decide on long-term management strategies
• Not Flexible (esp. if no suprises)
• Adaptive management framework that allows
  adjustment as more information comes in
• need a carefully designed and well funded
  scientific management program for the ecosystem
• that can be expensive, but costs are predictable
• Provide public funds for SUPRISES

56
More Criticisms (Minett Cullinan 1997 Kaiser
1997)

• Separate plans for single landowners results in
  fragmented approach to conservation
• not a problem if landowners hold large areas
• can result in high grading
• first HCP gets by with as much as possible
• subsequent HCPs have to conserve species given
  what is already provided
• they may have to provide more expensive habitat
  or curtain operations to a greater extent than
  first planer
• plans rely on particular use of adjoining land
• Multi-owner (regional) HCPs would be better

57
HCPs are not Recovery Plans

• Another criticism is that HCPs often do little
  for the listed species
• Requirement is that plan MINIMIZES and MITIGATES
  take
• they do not have to contribute to RECOVERY
• alternatives easily dismissed
• Rotas proposed HCP would take 1/2 of Mariana
  Crows habitat!
• Balcones Canyonlands HCP (Texas) provided 12,000
  ha, but science report called for 53,000 ha
• black-capped vireo is likely to go locally
  extinct

58
Limited Public Participation

• A serious criticism from environmental
  organizations
• Years of negotiation between service and
  landowner prior to review
• Service does not have to use public comments
  obtained during review when making their final
  decision
• Too much invested in negotiations to change after
  public comments
• Environmental organizations are out of loop and
  dont like it

59
Making HCPs Better (Kaiser 1997)

• Require plan to boost, not reduce, populations of
  listed species
• Initial plan developed by scientists with no
  vested interests in planning area
• Wait for recovery plan before HCP is approved
• allows range-wide coordination of efforts
• Allow for adjustment even with no surprise
• public funding for surprises
• good monitoring and adaptive response

60
An Example of a Good Plan (NRC and Kaiser 1997)

• Californias Natural Community Conservation Plan
• southern coastal sage
• Regional
• provides protection for more than just listed
  (gnatcatcher) species so future plans are less
  likely
• Blueprint drafted by panel of independent
  scientists
• functioned as interim plan
• pointed out needs for research on dispersal,
  demography, genetics, ecology before final plan

61
Population Viability Analysis (PVA)

• Objective Determine the minimum viable
  population (MVP)
• the smallest number of breeding individuals
  that has a specified probablity of surviving for
  a certain time, without losing its evolutionary
  adaptability.( a safe population size)

62
Population Viability Analysis (PVA)

• Approaches
• 1) Determination of the size of populations that
  have persisted for a known length of time.
• Example Population sizes of mammals that have
  remained in national parks in western U.S. since
  the parks were established.
• Compared with those that became extinct over 75
  years.

63
Population Viability Analysis (PVA)

• 2) Modeling population dynamics
• using population growth rate and
• its variability
• Evaluate environmental
• catastrophic events

64
What Reasons are Listed For Endangerment in US?
(Czech and Krasuman 1997)
65
What Reasons are Listed For Endangerment in US?
(Czech and Krasuman 1997)
66
Example of Stochasticity at Work

• 1876 only on Marthas Vineyard
• 1900
• 1907 refuge and predator control
• 800 by 1907
• fire (catastrophe)
• high winter predation by goshawks, then disease
  (both environmental stochasticity) reduced
  population to
• sterility, male biased sex ratio (Demographic
  stochasticity)
• 1932 EXTINCTION

Heath Hen
67
A positive story Lord Howe Island Woodhen
(Australia)

• Down to 20 individuals, confined to two mountain
  tops in 1970s
• Did experiments to determine impacts of
• food availability
• rat predation
• pig predation
• Remove Pigs

68
A positive story Lord Howe Island Woodhen

• Captive Breed, reintroduce
• Population up to 200 in 1997
• Now should do reserve planning to manage entire
  island

69
E.O. Wilsons HIPPO factors

• Typically we are up against
• Habitat destruction/degradation
• Invasive species (exotics)
• Pollution
• Population growth of humans
• Overharvest
• Pollution and overharvest are easiest factors to
  remove or control
• More people (population growth) means more of all
  other factors

70
Removing the Cause of Decline

• This is really the crux of endangered species
  conservation
• Requires detailed observation and likely
  experimentation to fully understand reason for
  decline
• Brown tree snake was not immediately recognized
• Condor limiting factors required much study
• not pesticide, not disturbance at nest, not
  shooting, likely lead poison because Condors need
  open habitat to find food and hunters/ranchers
  common there

71
Recovery after Agent of Decline Removed

• Stop Overharvest
• whales, alligator
• Remove Pesticides
• Peregrine Falcon, Bald Eagle, Brown Pelican all
  responded to DDT ban in North America

72
Are The Threats Changing Over Time?

• Possible decline in over-exploitation and
  pollution
• Increase in impact of exotic/invasive species
• Habitat likely to remain No. 1

• Same states with high number of endangered
  species have high population growth Hawaii,
  Florida, California ( 20)

73
Exotics are Very Difficult to Control

• Brown tree snake (Pacific islands)
• Technology not adequate to control
• Buy time by marooning species
• release small numbers of species with poor
  dispersal ability in isolated habitat (typically
  islands)
• 700 islands off New Zealand
• Kakapo (flightless parrot), Takahe (Rail)
• Buys time until introduced mammals can be removed
• Guam Rail released on Rota

74
Are We Treating the Symptom or the Cause of the
Problem?

• Often rush into captive breeding without
  addressing limiting factor
• Headstarting Sea Turtles (Tate 1990)
• rear until old enough to avoid predation on
  nesting grounds
• wouldnt it be better to protect nesting ground?
• Hatcheries and barges for Salmon
• damns, habitat loss, fishing, etc are cause

75
A Complex Example of Addressing Limiting Factors

• Rhinos in Africa http//gurukul.ucc.american.edu/T
  ed/RHINOBLK.HTM
• Destruction of habitat, hunting, illegal trade in
  products (folk medicine, dagger handles)
• reduction in numbers from 65,000-100,000 in 1960s
  to 3,000 today
• regulations (CITES)
• scientific study of medicinal effects
• Leader of Yemen using agate handle dagger
• shoot to kill poacher policy
• De-horning living wild animals
• Ranching to flood market

76
Little Progress with Rhinos

• Cant change old beliefs quickly
• medicinal effects of horn
• Value of horn in poor countries makes risk of
  death worth it
• De-horning not very effective
• grow back (possible sustainable harvest?)
• de-horned animals killed out of spite
• even small portion of horn near skull valuable
• dehorned mothers cant defend calves from hyenas
• Need to work at both ends of trade routes

77
How Do We Protect or Restore Enough Habitat?

• Biopolitical Considerations (Kleiman et al. 1994)
• No negative impact for locals
• Community support exists
• Government and non-governmental groups
  supportive/involved
• But what about when there is an obvious Economic
  Cost?
• Especially when habitat is already being used by
  humans - for example, salmon in Northwest

78
Captive Breeding and Reintroduction

• Once the limiting factors have been addressed it
  might be time for intensive management
• last resort
• expensive
• difficult to make succeed
• Beck et al. 1994-- 11 successful
• Griffith et al. 1989-- 19 successful
• requires large, long-term effort in captivity and
  the wild

79
Typical Questions About Captive Breeding

• Is it necessary?
• Is it successful and worth it?
• How do you do it?
• Technical questions about breeding, rearing, and
  release

80
Example of captive breeding

• California Condor (more info in Ch. 26)
• Wild birds brought into captivity in early 80s
  (only 22 left in 1982)
• Captive population doing well (115 as of January
  2003)

81
Example of captive breeding

• Current wild population
• Arizona 33
• Southern California 21
• Baja California 3
• Central California 23
• Deaths due to collisions with power lines, lead
  poisoning

82
Example of captive breeding

• Peregrine Fund has lots of information
• http//www.peregrinefund.org/condor_factsheet.html

83
So, What Do We Do?
Use Scientific Method to Identify Threat
Determine Spatial Extent of Protection
?
Set up Reserves
REMOVE THREAT
Manage existing population
Captive Breeding
Monitor whether Threat is Removed
Monitor Recovery
Restock
84
Population Viability Analysis (PVA)

• Objective Determine the minimum viable
  population (MVP)
• the smallest number of breeding individuals
  that has a specified probablity of surviving for
  a certain time, without losing its evolutionary
  adaptability(a safe population size)

85
Population Viability Analysis (PVA)

• Approaches
• 1) Determination of the size of populations that
  have persisted for a known length of time.
• Example Population sizes of mammals that have
  remained in national parks in western U.S. since
  the parks were established.
• Compared with those that became extinct over 75
  years.

86
Population Viability Analysis (PVA)

• 2) Modeling population dynamics
• using population growth rate and
• its variability
• Evaluate environmental catastrophic events
• Example modeling changes in Spotted Owl
  population based on projected changes in habitat

87
Conflicts and Connections Between Species
Hawaiian Hawk, io
Hawaiian Crow, alala
88
Io Background

• Hawaiian hawk, Buteo solitarius
• Listed as endangered in 1967
• Population est. 1500 - 2500 (Griffin 1985)
• endemic to island of Hawaii
• distributed throughout mature native and exotic
  forest (sea level to 6000)

89
Alala Background

• Hawaiian Crow, Corvus hawaiiensis
• listed in mid 1970s
• 4 birds in wild, 28 captive
• endemic to island of Hawaii
• found on 15,000 acres on USFWS refuge and private
  ranch in southeastern portion of island.
• elevation range 3500 - 6000 ft.

90
Io and Alala distribution (USFWS unpub.
data)
Io
Alala
91
Habitat/Food

• Alala (NRC 1992)
• Mature, closed canopy native forest.
• Feeds on native fruits, some exotic fruits,
  invertebrates, nestlings.

• Io (Griffin 1985)
• moderate densities mature, closed canopy,
  undisturbed native forest.
• high densities native forest edges. Native
  forest with grass understory.
• Feeds on rodents, passerines, game birds, ...

92
Alala/Io Conflict

• Io implicated in deaths of 7 of 24 alala deaths
  since alala releases began in 1993. (USFWS
  unpub. data)
• Important to realize that io may be predating
  compromised alala.
• Io observed stooping crows on weekly basis.
• Io observed removing nest material from alala
  nests.

93
Mitigating Io Impacts on Alala

• Io is endangered, so difficult to manage io to
  benefit alala.
• In the past two years, 9 io have been captured
  from alala area and sent to zoos for captive
  breeding.
• 2 io removed and translocated.
• In August 1998, all released alala pulled from
  wild into captivity.

94
Issues

• USFWS hoping to delist io for a success story
  and to allow more management options in alala
  areas.
• Io not primary reason for alala mortality.
• The delisting of io probably wont allow too
  many additional management options.

95
Effects of Habitat Management

• Fencing forests and removing ungulates - forest
  canopy closes and understory thickens. (high crow
  densities, low io.)
• Use of rodenticides (benefits to the crow,
  probably impact to io)

96
Conservation Conflicts Between Species NRC
(1995)

• ESA doesnt account for interactions of species
  in nature very well
• Northern goshawk and Mexican spotted owl
• different habitat conditions, goshawk may prey on
  young owls
• Marine mammals and salmonids
• Sea lions eat steelhead returning to spawn at
  Ballard locks, numbers returning declined through
  1990s