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What are the ecological consequences of gamebird release?
Review by me and Rufus Sage @Gameandwildlife
http://publications.naturalengland.org.uk/publication/5078605686374400
We scoured the published, grey and unpublished literature to document the ecological impacts of gamebird release
What did we find?
(Thread)
Review by me and Rufus Sage @Gameandwildlife
http://publications.naturalengland.org.uk/publication/5078605686374400
We scoured the published, grey and unpublished literature to document the ecological impacts of gamebird release
What did we find?
(Thread)
It's a Rapid Evidence Assessment, so didn't set out to make specific recommendations. Policy makers may use this evidence for future decisions
Joint funded @NaturalEngland & @BASCNews
Neither org had input to Review content other than stipulate remit (exclude ethic/econ/social)
Joint funded @NaturalEngland & @BASCNews
Neither org had input to Review content other than stipulate remit (exclude ethic/econ/social)
We scoured >3000 papers via formal searches and informal approaches to researchers in the field and sifted them for relevance to release & shooting of pheasant, RL partridge and mallard in the UK
Papers = 58 highly relevant; 60 moderately relevant; 101 weakly relevant
Papers = 58 highly relevant; 60 moderately relevant; 101 weakly relevant
We also made FOI requests on release data from the APHA Poultry Register and extracted data about advertising commercial game shoots. This provided new information about release locations and levels
Gamebird release & management is long-established & deeply integrated in English countryside, occurring at an ever-increasing scale & over large areas
Its ecological effects are complex, complicated & wide-reaching. Evidence should be considered in framework accounting for this
Its ecological effects are complex, complicated & wide-reaching. Evidence should be considered in framework accounting for this
The released birds have DIRECT EFFECTS
These are usually considered ecologically -ve: disturbing soil/plants, eating other wildlife, altering soil and water nutrients, spreading disease.
Some effects are ambiguous – carcasses may support popns of generalist preds or rare spp
These are usually considered ecologically -ve: disturbing soil/plants, eating other wildlife, altering soil and water nutrients, spreading disease.
Some effects are ambiguous – carcasses may support popns of generalist preds or rare spp
DIRECT EFFECTS generally spatially confined around release pens, but may be long-lasting
Some effects may be at broader scale – e.g. carcasses supporting preds, or disease spread
Effects
as birds die/shot over the year
-ve effects usually greater at high density releases
Some effects may be at broader scale – e.g. carcasses supporting preds, or disease spread
Effects
as birds die/shot over the year-ve effects usually greater at high density releases
The management of released birds has ASSOCIATED EFFECTS
Some of these are ecologically +ve: land management, habitat creation, legal pred control. Others are ambiguous – supp feeding may help overwrinter birds & rodent pests. Some are -ve – disturbance or shooting non-quarry spp
Some of these are ecologically +ve: land management, habitat creation, legal pred control. Others are ambiguous – supp feeding may help overwrinter birds & rodent pests. Some are -ve – disturbance or shooting non-quarry spp
ASSOCIATED EFFECTS are dependent on game manager motivation and may extend over large areas of countryside
Relationship with, and dependence on, release sizes is unclear
What would game managers do in absence of releasing & shooting? It's unclear, but suggested habitat care
Relationship with, and dependence on, release sizes is unclear
What would game managers do in absence of releasing & shooting? It's unclear, but suggested
habitat care
The birds & their management exert INDIRECT EFFECTS on wildlife & habitats
E.g. managed woods support more bird & inverts
E.g. Gamebirds eating inverts may deprive non-game spp of chick food
This is likely contingent on scale, location & extent of releases and locally variable
E.g. managed woods support more bird & inverts
E.g. Gamebirds eating inverts may deprive non-game spp of chick food
This is likely contingent on scale, location & extent of releases and locally variable
Calculating NET +ve or -ve values for these is difficult but critical
E.g. Does creation of 10 acres of woodland & inverts in it, motivated by release, outweigh reduction in invert popns by gamebird predation in 1 acre of woodland release pen?
Requires considering whole web
E.g. Does creation of 10 acres of woodland & inverts in it, motivated by release, outweigh reduction in invert popns by gamebird predation in 1 acre of woodland release pen?
Requires considering whole web
Assessing the evidence overall, we found surprisingly little work in this area given the potential effects, & many gaps in our knowledge. Currently, there appear to be conspicuous ecological +ves AND -ves to gamebird release but collapsing these to single NET effect is difficult
Key areas that we know little about:
Where gamebirds are released & how many
Released mallard (anything)
Disease in wildlife
Predation on verts (amphibians, reptiles)
Effects on generalist predators
Motivations of game managers
Disturbance
Where gamebirds are released & how manyReleased mallard (anything)Disease in wildlifePredation on verts (amphibians, reptiles)Effects on generalist predatorsMotivations of game managersDisturbance
Our reading of the literature and conducting the Review led us to the following Conclusion
(too many characters for Twitter, so pasted as an image)
(too many characters for Twitter, so pasted as an image)
