Managing Hunting Flashcards
Managing subsistence hunting to minimize extinction risk
Late Pleistocene megafaunal extinctions
97 genera of large mammals (megafauna >44 kg) went extinct Diprotodon, 3000 kg extinct ~46,000 yrs BP Glyptodon, 2000 kg extinct ~10,000 yrs BP
Megafaunal extinctions: man vs climate?
Low population densities (<1 person / km2)
Low technology
The expansion of man across the tropics
Rapid expansion of man in the late Pleistocene (~50,000-10,000 years BP)
Earlier arrival of man has lower extinctions: 18% Africa vs 83% South America
Barnosky et al. 2004 Science
Pre-industrial man lived in harmony with the environment?
He only took what he needed to survive
I.e. not driven by economic markets
Combined with climate change, human needs / population densities had major negative impacts on megafauna
What about hunting of smaller species in modern era?
Passenger pigeon
Extinct 1914
Wilson spotted flock of 2 billion crossing ohio river early 19th century
Danger of Allee effects: critical population size below which population growth is negative and species is doomed to extinction.
1521 listed mammals
673 (44%) threatened by hunting
IUCN Red List, 2015
Hoffmann et al 2011 Agriculture and aquaculture, hunting/trapping, logging, invasive species
leading causes for species loss
Dispersal limitation induces long-term biomass collapse in overhunted Amazonian forests
Large-bodied Atelinae primates and tapirs in particular offer nonredundant seed-dispersal services for many large-seeded Neotropical tree species, which on average have higher wood density than smaller-seeded and wind-dispersed trees. We project that defaunation of the most harvest-sensitive species will lead to losses in aboveground biomass of between 2.5–5.8% on average, with some losses as high as 26.5–37.8%.
Peres et al 2015
“losses in aboveground biomass of between 2.5–5.8% on average, with some losses as high as 26.5–37.8%”
These findings highlight an urgent need to manage the sustainability of game hunting in both protected and unprotected tropical forests, and place full biodiversity integrity, including populations of large frugivorous vertebrates, firmly in the agenda of reducing emissions from deforestation and forest degradation (REDD+) programs.
Preventing modern-day extinctions from subsistence hunting
Very remote places (Amazon, Congo, PNG)
10’s millions forest-dwellers rely on wild meat
Brazilian Amazon 15.8 million game mammals consumed per year (Peres 2000 Conserv Biol)
How meet demand without extinction?
Manu national park on the madre de dios
Mashco-Piros appear on the border of Manu Park in late 2011
The uncontacted indians of Peru
The sustainability index approach: How much habitat is needed to sustain game offtake?
Measure offtake
Robinson-Redford or
Bodmer indices
Amount of habitat needed to sustain offtake
How much habitat is needed to sustain a given offtake?
Participatory monitoring of bushmeat & fish exploitation
Now: Spider monkey offtake requires ~ 25% of Manu Park (using Bodmer index)
Manu National Park
17,898 km2
~size of Wales
Established 1973
Core area of Manu Biosphere Reserve
Core area includes several indigenous populations
Settled Communities Matsigenka - ~700 Yomybato Tayakome 16 year doubling time \+4.5% per year Matsigenka population to exceed Manu’s capacity in about 50 years
“The Danger Within”
Terborgh (1999) Requiem for Nature, Island Press
In the…brief period I have known the park, one village…has spawned three communities….
…I fear the no-hunting zone around the research station will become impossible to maintain. That will be the signal that my years in the Manu…have reached their end.
…the Manu will imperceptibly pass from being a National Park to being a reserve for its indigenous inhabitants.
human population growth, settlement maps, offtake measure, hunter walking distances, monkey population parameters, weapons parameters, encounter rates….
Assumptions of their model
Spider monkeys: logistic population growth and low migration rates
50 years of Matsigenka population growth
Normal distribution of walking distances
40 hunts per hunter per year (effort assumption)
Bow-and-arrow (technology assumption)
6 villages (geography assumption)
Modelling the long-term sustainability of indigenous hunting in Manu national park
In 50 years, how many spider monkeys will be in Manu Park?
Yes, lots
But changing assumptions, 50 years from now…There could be more Villages and they could have guns
Summary
Spider monkeys persist in all futures
Worst-case: ~70% of Manu near carrying capacity
Policy recommendations for Manu
Cooperative agreement to limit shotguns in Manu
Only the Matsigenka can monitor themselves
Discourage the establishment of new villages(big help, even if they switch to guns)
Encourage the growth of existing villages
Why do they get these results?
Ohl-Schacherer et al. 2007. The sustainability of subsistence hunting by Matsigenka native communities in Manu National Park, Peru. Conservation Biology 21:1174-1185.
People live in villages
Adding more people to the same village has little effect on monkeys as hunters will not travel further
How can we limit the spread of Matsigenka villages?
And how can we do this over the long term?
Clean water reduces disease burden, which reduces social stress, which reduces village fragmentation
Clean water comes from Rainforest Flow (houseofthechildren.org)
Izquierdo et al. (2010) Revenge, envy and sorcery in an Amazonian society. In: Revenge in the cultures of lowland South America, eds. S. Beckerman & P. Valentine. Gainesville, FL: University Press of Florida.
Shepard et al. (2010) Trouble in paradise: indigenous populations, anthropological policies, and biodiversity conservation in Manu National Park, Peru. Journal of Sustainable Forestry 29: 252–301.
Good schools reduce early pregnancies, which reduces population growth rate, and helps the Matsigenka become conservation partners for Manu
Yu, D.W., Levi, T. & Shepard, G.H. (2010) Conservation in low-governance environments. Biotropica 42: 569–571.
