|To:||Geoffrey Dabb <>|
|Subject:||Re: FW: [canberrabirds] dogs and wetlands|
|From:||mary bomford <>|
|Date:||Tue, 29 Jul 2014 16:04:14 +1000|
Banks and Bryant (2007) is nicely conducted research. These authors compared bird abundance under three treatments – sites with:
1.“walkers with dogs on lead”
2. “walkers without dogs”
3. “no walkers or dogs”
They did NOT compare bird abundance for “walkers with dogs on lead” vs “walkers with dogs off-lead” which would be the relevant comparison for the proposed rezoning of areas from dogs off-lead to dogs on-lead. Therefore I don't think Banks and Bryant's (2007) study can be used to determine whether such rezoning would have benefits for birds.
Unfortunately Banks and Bryant (2007) do not present their data, only a graph, so it is a little hard to quantify their results. But roughly I calculate from their graph that the presence of ‘walkers without dogs’ caused an average 21% drop in numbers of individual birds and an average 18% drop in numbers of bird species compared to ‘no walkers’. If the walkers had dogs on leash this caused a further (additional) average drop of 25% in numbers of individual birds and an average 22% drop in numbers of bird species compared to ‘walkers without dogs’. Banks and Bryant (2007) conducted their bird counts immediately after a walker or walker plus dog passed through their study sites, so they did not measure how long the birds stayed away following the disturbance.
I find the most interesting data in Banks and Bryant (2007) is the numbers of birds in their study sites BEFORE they implemented their treatments. Of the 90 sites they selected, half were in areas where dog walking was permitted and the other half were in areas where dog walking was banned. They found the average abundance of birds and average bird species diversity were the SAME IN BOTH TYPES OF SITES (see their Figure), indicating that the presence of dogs was having no long term effects on either bird abundance or species diversity! Banks and Bryant (2007) state this succinctly “We found no net difference in bird diversity or abundance between areas with and without regular dog walking receiving the same treatment, suggesting that long-term impacts in this area may be small.”
This leaves me puzzled as to why people keep citing Banks and Bryant (2007) as justification for the claim that keeping dogs on their leads will increase bird abundance? Whether or not dogs should be kept on leads at Dickson wetlands should be the subject of expert advice, taking into account both community and conservation interests, but I don't think Banks and Bryant's (2007) study adds anything to the case justifying dogs being kept on lead.
On Tue, Jul 29, 2014 at 2:00 PM, Geoffrey Dabb <> wrote:
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