Breeding and Non-breeding Survival of Lesser Prairie-Chickens in Texas

1

HARVEST MANAGEMENT
John W. Connelly1, James H. Gammonley2 and Thomas
W. Keegan3
1Idaho Department of Fish and Game, 1345 Barton
Road, Pocatello, ID 83221 2Colorado Division of
Wildlife, 317 W. Prospect Road Fort Collins, CO
80526 3Idaho Department of Fish and Game,
99Highway 93 N, Salmon, ID 83467
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INTRODUCTION

• Interest in managing harvests has been widespread
  throughout history
• Elements can be dated to the eighth century when
  Charlemagne instituted a detailed set of game
  laws
• Harvest management in North America dates to
  colonial times
• Enactment of Federal Aid to Wildlife Restoration
  Act in 1937 provided states with a stable funding
  source to further support harvest management
  programs
• For many biologists working for state and
  provincial wildlife agencies, harvest management
  is where the rubber meets the road
• Our purpose is to discuss the rationale and
  biology underlying harvest management in NA and
  provide examples of successful programs
• We also provide a synopsis of literature and
  attempt to identify and discuss principles

3
RATIONALE FOR HARVEST

• In North America, states and provinces are
  responsible for harvest regulations pertaining to
  resident wildlife, while federal authorities
  set regulations for migratory game birds
• A general underpinning of a harvest management is
  that a biological surplus exists, which can be
  harvested with little impact on subsequent
  breeding populations

4
Approaches to Harvest Management

• The 3 approaches to harvest management include
• (1) harvesting at a low rate to ensure population
  increase
• (2) harvesting to maintain a population
• (3) harvesting to reduce a population

5
Basic Components of Harvest Management

• Harvest management includes 3 basic components
• (1) inventory of populations
• (2) identification of population and harvest
  goals
• (3) development of regulations allowing goals to
  be met

6
Requirements for Successful Management

• Four basic requirements for successful, informed
  management of harvests
• 1. Develop and agree upon explicit goals and
  objectives
• 2. Implement actions designed to achieve
  objectives
• 3. Have some idea of the likely effects of
  alternative management actions
• 4. Measure the outcome of actions in relation to
  management objectives

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PrinciplesPast and Present

• Additive Mortality
• Each animal killed by hunters is an additional
  death that adds to natural mortality, resulting
  in total mortality being greater than if hunting
  did not occur
• Mackie et al. (1998) reported that hunting was
  additive to overwinter mortality for white-tailed
  and mule deer Bergerud (1988) suggested this
  applied to many grouse species
• Compensatory Mortality
• Occurs when animals have relatively stable annual
  mortality, regardless of which decimating factors
  may be acting on the population
• Recent work suggests upland game hunting
  mortality is often not compensatory

8
Additional PrinciplesPast and Present

• Diminishing Returns
• Indicates that, past a certain point, hunting is
  largely unrewarded, resulting in relatively few
  hunters in the field, suggesting hunting is
  largely self-regulating
• The idea of diminishing returns appears to have
  little value for present-day harvest management
• Doomed Surplus
• Number of animals produced that exceed the
  capacity of the habitat to support and keep
  secure from predation
• A number of wildlife species actually have high
  overwinter survival and this concept seems to
  have limited usefulness

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Additional Principles

• Harvestable Surplus
• Indicates most animals produce more young than
  necessary to maintain the population this excess
  can be removed by hunting without affecting the
  population.
• McCullough (1979) challenged this concept by
  arguing that it fails to include the dynamic and
  compensatory nature of population responses.
• Inversity
• An inverse relationship has been proposed to
  exist between productivity and abundance
• Roseberry (1979) concluded that the systems
  ability to compensate for hunting losses
  progressively deteriorates as harvest increases

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More Principles

• Opening Day Phenomenon
• Suggests most mortality for a given species
  occurs on opening day of the season because that
  is when most hunters are afield
• Appear to be few published data available
  documenting hunting pressure and harvest
  throughout the season
• Threshold of Security
• Population size above which some animals are not
  secure from predation
• Romesburg (1981) indicated this concept passed
  into the wildlife profession without being
  critically evaluated or tested

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Sources of Uncertainty

• Sources of uncertainty about the relationship
  between hunting regulations and game populations
• Partial Observability
• Partial Management Control
• Structural Uncertainty
• Environmental Variation

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Management of UplandGame Harvests

• Development of Harvest Strategies
• Early Years (19001944)
• Largely characterized by reduction in bag limits
  and season length for many species of upland game
• Changing Strategies (19451980)
• Harvest strategies tended to stabilize and became
  somewhat more liberal in the 1960s and 1970s
• There was a strong tendency to believe
  reproductive characteristics and effects of
  exploitation were the same for all species of
  upland game

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Development of Harvest Strategies for Upland Game

• Current Knowledge (19812009) A New Paradigm
• New information suggesting earlier views of
  harvest management were not always correct
• During 1980s and 1990s, evidence began to suggest
  that, under some circumstances, harvesting may
  have an additive effect
• Recent information suggests hunting mortality
  should be viewed as occurring along a continuum
  and not as categorical (i.e., either compensatory
  or additive)

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Inventory of Upland Game

• Inventory
• A general approach would base harvest on
  abundance of the species, but this is rarely done
  for upland game
• Instead, most harvest strategies seem to have
  been developed through trial and error

15
Harvest Surveys of Upland Game

• Harvest Surveys
• Most states have reduced emphasis on population
  monitoring because of emphasized collection of
  harvest data
• Many estimates of harvest have wide confidence
  intervals, making comparisons among areas or
  years difficult
• Lack of population data makes it virtually
  impossible to assess proportion of the population
  taken by hunters

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Developing Regulations for Upland Game

• Developing Regulations
• Varies among wildlife agencies
• Initial steps include
• Soliciting comments from agency personnel and
  public
• Regions or other administrative units then
  formulate recommendations for the chief
  administrator of the agencys wildlife program
• Recommendations are discussed with the agency
  director
• Recommendations are passed on to the Wildlife
  Commission for approval

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Population Responses of Upland Game to Hunting

• Population Responses to Hunting
• Until the late 1970s, most studies suggested
  there were few adverse effects of exploitation on
  upland game
• Within the last 25 years, numerous studies have
  documented adverse effects of hunting on upland
  game species
• Kokko (2001) warned that ignoring information on
  species and population characteristics will
  easily cause hunting to be harmful to an
  unnecessary extent.

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Future Directions in Upland Game Management

• Stocking
• Seen as a legitimate and often necessary function
  of harvest management
• Stocking is likely reinforced among the hunting
  public because stocking is a common activity of
  fisheries management
• 2 different harvest management programs involving
  game bird stocking
• Release of birds before the gun
• Establish or augment existing game bird
  populations

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Upland Game Shooting Preserves

• Shooting Preserves
• Hunting preserves offer additional hunting
  opportunity and a chance for individuals to train
  dogs prior to a general season
• Appear to fill a need for more hunting areas at
  which hunters have a better than average chance
  at being successful

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Development of Harvest Strategies for Migratory
Game-birds

• Approaches have been shaped primarily by
  recognition these animals routinely cross local,
  state, provincial, and international borders
• Effective monitoring of populations and harvests,
  and development of regulations depends on
  cooperation across multiple levels of government
• Until reliable population and harvest surveys
  were developed, regulations in the United States
  were set subjectively
• As information was incorporated into the
  regulatory process, regional or flyway-specific
  differences were recognized, and regulations
  became more spatially complex

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Models for Setting Regulations for Migratory
Game-birds

• Models were developed for use in setting
  regulations, incorporating information from
  large-scale operational monitoring programs
• Early models assumed hunting mortality was
  completely additive and density-independent
• Anderson and Burnham (1976) produced new
  analyses indicating compensatory mortality and
  introduced the concept of structural uncertainty

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Subsequent Model Analyses

• Subsequent analyses provided mixed evidence on
  effects of hunting on annual survival in ducks,
  but hunting mortality appears to be primarily
  additive for geese
• Recognition of alternative hypotheses about
  effects of hunting on population dynamics led to
  a greater focus on addressing partial management
  control and structural uncertainty
• After a period of stabilized regulations, federal
  authorities in the United States adopted risk
  aversive conservatism toward setting hunting
  regulations
• Relatively restrictive regulations would be
  adopted for populations at low levels

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Inventory of Migratory Game-birds

• Federal mandates to consider status of migratory
  game birds when setting regulations motivated
  development of extensive monitoring programs in
  North America
• Monitoring programs support annual regulatory
  process and consist of annual collection of data
  on abundance, production, distribution, harvest,
  other population parameters, and habitat
• Population monitoring programs for waterfowl have
  a longer history and are more extensive than
  surveys developed for most other migratory game
  birds
• Since 1955, the U.S. Fish and Wildlife Service
  and the Canadian Wildlife Service have conducted
  annual aerial transect surveys, coupled with
  ground counts during May
• Winter (Jan) surveys of waterfowl have been
  conducted since the 1930s
• This survey is still the primary population index
  for ducks that occur outside of the May survey
  area, and provides population indices for many
  goose populations in North America
• During May and July aerial waterfowl surveys
  observers record the number of ponds containing
  water along transects in southern Canada and the
  north-central US
• The Canadian Wildlife Service monitors wetland
  habitat conditions on a sample of survey
  transects each year in southern Canada

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Annual Harvest Estimates for Migratory Game-birds

• Annual harvest estimates are obtained using
  surveys consisting of 2 components
• Hunter Questionnaire Survey is used to obtain
  information on hunter activity and number of
  ducks and geese harvested each year
• Parts Collection Survey involves mailing
  envelopes to a sample of hunters who are asked to
  mail in wings of ducks and tail feathers of geese
  they shoot

25
Harvest Information Program for Migratory
Game-birds

• In 1991, a new Harvest Information Program was
  initiated to provide a reliable, nationwide
  sampling frame of all migratory bird hunters
• Under HIP, each state collects the name, address,
  and birth date of each person hunting migratory
  game birds, asks each hunter a series of
  questions about their hunting success the
  previous year and provides this information to
  the USFWS
• The traditional sampling procedure was replaced
  with the HIP sampling frame beginning with the
  20022003 hunting season

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Role of Banding for Migratory Game-bird Management

• Markrecovery methods enable managers to obtain
  important information about populations. To use
  these methods, individually numbered leg bands
  are placed on migratory game birds
• Information helps identify distribution of
  harvest and harvest areas, estimate harvest rates
  and relative vulnerabilities to harvest of gender
  and age cohorts, and estimate age- and
  gender-specific survival rates

27
Governmental Roles in Regulating Hunting of
Migratory Game-birds

• Primary federal authority and responsibility for
  migratory birds was established after the signing
  of the Convention for the Protection of Migratory
  Birds by representatives from the United States
  and Great Britain in 1916
• Migratory Bird Treaty Act of 1918 implemented the
  convention in the US
• This Act was later amended to incorporate similar
  treaties with Mexico, Japan, and Russia
• Under the Migratory Bird Treaty Act, the
  Secretary of the Interior authorizes hunting and
  adops regulations for this purpose
• Regulations must be based on status and
  distribution of migratory game birds and updated
  annually
• This responsibility has been delegated to the
  U.S. Fish and Wildlife Service

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Flyway Councils

• In 1947 the United States was divided into 4
  administrative Flyway Councils for establishing
  annual hunting regulations
• Through these Councils, representatives from
  state and federal agencies in the United States,
  Canada, and Mexico have coordinate management
  activities and develop annual hunting regulations

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The Regulations Process
Regulations process Month Monitoring
U.S. Fish and Wildlife Service regulations Committee (SRC) meets to identify issues Flyway Councils develop recommendations January February March Midwinter waterfowl and crane surveys Parts Collection Survey wing bees Hunter Questionnaire Surveys banding analysis for duck harvest and survival rates
AprilMay Breeding waterfowl and habitat, dove call-count, and woodcock singing-ground surveys
SRC meets to recommend early season regulations Harvest survey results available June Harvest survey results available
Flyway Councils develop recommendations July Waterfowl production surveys
SRC recommend late season regulations August Preseason duck banding
Early hunting seasons begin September Autumn surveys for sandhill cranes, greater white-fronted geese
Late hunting seasons begin October
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Management of Migratory Game-bird Harvests

• Features of adaptive harvest management for
  mallard populations
• Set of alternative models
• Measure of reliability for each model
• Limited set of regulatory alternatives
• Objective function or mathematical description of
  the objective(s)
• The setting of annual hunting regulations
  involves a 4-step process
• Each year the optimal regulatory alternative is
  identified
• Once the regulatory decision is made,
  model-specific predictions for subsequent
  breeding population size are calculated
• When monitoring data are available, model weights
  are updated
• New model weights used to start a new iteration
  of the process

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Harvest Management of Overabundant Species

• Primary goal for migratory game birds continues
  to be prevention of overharvests
• However, hunting has often been used to reduce or
  control the density of birds on local scales
• Several continental populations of geese have
  grown rapidly
• In 1999, U.S. Fish and Wildlife Service
  authorized new methods of take for light geese
  and established a conservation order permitting
  take outside dates established by Migratory Bird
  Treaty Act

32
Management of Big Game Harvests

• In contrast to harvest management of upland game
  and waterfowl, management of big game harvest is
  often more complex and contentious because
• Ability of hunters to differentiate among gender
  and age classes
• Variety of weapons used for harvest

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MANAGEMENT OF BIG GAME Populations

• Management of large mammal populations is a
  4-step, linear process
• (1) inventory (identify current or potential
  population status)
• (2) define goals and objectives (identify desired
  population status)
• (3) develop strategies to achieve objectives,
• (4) evaluate how well strategies met objectives

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Inventory of Big Game

• Typically involves estimating current population
  status
• Biological capacity to produce and sustain a
  given species
• Should be based on geographical areas containing
  relatively discrete populations
• Inventories may be designed to estimate
  population abundance or provide an index to
  population status
• Determine age and gender ratios

35
Harvest Surveys for Big Game

• Harvest Surveys
• Surveys conducted by wildlife agencies estimate
  harvest across multiple species, seasons, weapon
  types, and management units
• Data collected include number of animals
  harvested by gender and age class, hunter effort,
  location, date of harvest, weapon used
• Variety of methods to estimate harvest
• Check stations, mandatory checks, report cards,
  random mail or telephone surveys, toll-free
  telephone service, Internet- based reporting

36
Harvest Strategies for Big Game

• Development of Harvest Strategies
• Harvest theory for most big game species is
  generally based on concepts of biological
  carrying capacity (K) and density-dependent
  population growth
• Determination of K for wild populations is very
  difficult K often changes through time
• Practical management of big game populations is
  more likely to be based on social carrying
  capacity

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Developing Regulations for Big Game

• Wide variety of harvest regulations and season
  structures are applied across jurisdictions and
  species
• Local tradition and history often play important
  roles in determining harvest systems
• Regulations should be easily understood by
  hunters and enforceable
• Concept of fair chase is integral to developing
  regulations, but definition of fair chase varies
• To provide a framework for evaluation, managers
  should implement regulations that are consistent
  and stable over long enough periods to encompass
  normal variability
• Changing season length and timing annually will
  virtually eliminate the possibility of estimating
  effects of different season structures
• Evaluation is an often neglected aspect of the
  regulation process

38
Population Responses of White- tailed Deer to
Hunting

• Challenge for managers is finding ways to
  increase harvest, particularly for females
• Principles of sustained yield management based on
  density dependence can be applied with more
  certainty than in more variable systems

39
Population Responses of Mule Deer to Hunting

• Minimum APRs are generally effective at reducing
  buck mortality and increasing total buckdoe
  ratios, but have almost invariably failed to
  increase mature buckdoe ratios or absolute
  number of mature bucks
• Effects of altering season length are equivocal
  and typically confounded by concurrent change in
  season timing
• In general, reducing the number of days available
  to hunt has a negligible effect on total harvest
• Altering harvest management to increase buck
  ratios for the explicit purpose of increasing
  productivity is unwarranted
• Effects of female harvest depend on adult female
  natural mortality rates and fawn recruitment
• Determine appropriate harvest rates based on
  population-specific demographic data and
  population monitoring

40
Population Responses of Elk to Hunting

• Several regulatory approaches have proven
  successful in increasing bullcow ratios
• Moving centerfire-weapon seasons out of rut
  typically reduces bull harvest rates
• Maximum APRs (i.e., spike-only) may increase bull
  ratios
• A somewhat complex season system designed to
  attract hunters to seasons where they would be
  less successful may increase bull ratios

41
Population Responses of Bear to Hunting

• As harvest rates increase, average age of males
  declines and proportion of females in harvest
  increases
• If females comprise 35 of harvest and average
  age of males is 4, population is likely stable
• Refuge areas may serve as repopulation sources
  for more heavily hunted areas

42
Sustained Yield Management

• Maximum sustained yield (MSY) is achieved when
  populations are at approximately K/2
• Management for MSY has received criticism and
  been blamed for overharvest of some species
• In systems characterized by large variability in
  weather and habitat, density-dependent population
  responses may be overshadowed by stochastic
  processes, thus reducing appropriate yield levels

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Principles of Sustained Yield Management

• Any exploitation of a population reduces its
  abundance
• Below a certain exploitation level, populations
  may be resilient and increase survival and/or
  production and growth rates to compensate for
  individuals removed
• When populations are regulated through density
  dependent processes, exploitation rates will tend
  to increase productivity and reduce natural
  mortality of remaining individuals
• Exploitation rates above maximum sustained yield
  will reach a point at which extinction will occur
  if exploitation is continued

• Age composition and number of animals remaining
  after exploitation are key factors in the
  dynamics of exploited populations
• If a population is stable, it must be reduced
  below that density to generate a harvestable
  surplus
• For each density to which a population is
  reduced, there is an appropriate sustained yield
• For each sustained yield, there are 2 density
  levels at which it can be harvested
• Maximum sustained yield may be harvested at only
  one density, about 1-half resource based carrying
  capacity

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SUMMARY

• As interest of nonhunters in management
  increases, importance of biologically defensible
  harvests also will increase
• Changing landscapes will alter at least some
  wildlife populations
• Approaches to harvest management for some
  populations will likely have to change
• Management decisions backed by sound science and
  rigorous data collection will alleviate some
  difficulties