Market Hunting - See text
Midcontinent Light Geese Example
Includes Greater and Lesser Snow Geese (blue and white color phases)and Ross geese
Greater and Lesser Snow geese on Atlantic and Mississippi Flyways Use Hudson’s Bayas breeding ground and stopover areas (“Midcontinental light geese”)
Why the Increase?1) Agriculture2) Sanctuaries3) Reduced Hunter Harvest4) Climate shift on BG
Result:Higher adult survival/conditionHigher repro
Population sizes from 1968-1993
1965 present:
Greater Snow 30,000 600,000 Lesser Snow 1 3 millionRoss 30,000 400,000
Goose “grubbing” for rhizomes & tubers results in majorshifts in vegetation
Hudson Bay Study Site1984
1997
Is it really geese?
Is it really geese? – The exclosure experiment
At Hudson Bay 35% of habitat destroyed, 30 % damaged, 35% overgrazed
1) Season
2) Method of Take
3) Bag Limit
4) # of Hunters
5) Which animals
Recall the ways hunting can be used to alter outcome:
Management Response 1999Conservation Order Light Goose Hunts ordered by USFWS
1) Extend Hunting Season into Spring2) Methods
Electronic callsNo limit on number shells shotgun contains
3) Bag limit No daily bag limit imposed, set by states
The management goal for light geese in the mid-continent region is to reduce the population by 50% from the level observed in the late1990s. The management goal for greater snow geese is to reduce the population to 500,000 birds.
USFWSFinal Environmental Impact Statement:Light Goose Management June 2007
Lethal Trapping - More controversial than hunting See Table 10-3 for pro-con views
Snare
Leghold trap
1994 AZ Ban on trapping on federal/state lands
Effect on harvest – lab exercise
Current Regulations:1) Only on private lands or special designations
2) License, written exam, course required
3) All traps labeled, padded jaws, offset
4) Checked daily, kill target or release non-target
5) Written annual report to AZGFD
Exemptions:
1) Livestock losses2) Federal, state, county, local health departments3) Rodent control
Examples of use of trapping:1) Mesocarnivores on refuges/breeding grounds
Garretson and Rohwer 2001. JWM 65:398-405.
16 41km2 sites, ½ trapped other not trapped Trappers paid $18,000 for 5 mos 2404 coons, skunks and foxes Response: Doubled duck nesting success 23% vs 43% and return rate(so what was management goal in this case?)
Recommendations:
1) Treat large areas, with high repro potential2) May not be necessary where coyotes prey
on coons, skunks and foxes
3) Need public acceptance – rural area so acceptance was… high or low?
2) Introduced Exotic Species Nutria (Coypu) Native of South America
5-8 young/litter 2-3 litters per year
Introduced for fur in 1930’s
Intro in La in 1930 – 20 million by 1950
1970 – 10,000 trappers in La1998 - 1,700
Effects:Destroy leveesConsume cropsConvert marsh to open waterCost: millions of $
Chesapeake Bay of Maryland
CONTROL Options???
Lethal Trapping – worked in Great Britain where coypu eradicated
Alternatives to lethal trapping?
1) Live trapping and removal Cost Remove to where?
2) Contraception Cost Availability
3) Poison Non-target effects Reduced suffering? Limiting access
4) Reintroduce predators Feasibility Acceptance
Arizona’s Coypu?