Variations in bird diversity across Dublin city Michael Brennan, Tom Hayden, Tamara Hochstrasser Ub Urban Environment tproject t( (www.uep.ie) School of Biology & Environmental Science, UCD Urban Institute Ireland, UCD
Introduction Outline Questions: what do we want to know? The Garden Bird Survey Answers Discussion Conclusion Future work
Introduction The (www.uep.ie), what is it? The UEP aims to create a decision support tool so that informed choices and decisions can be made by policy makers and practitioners at both national and local levels.
Introduction Urbanisation and sub-urbanisation urbanisation, with associated loss in biodiversity, are major global trends (Fernández-Juricic, 2001). However, the importance of biodiversity in urban areas is increasingly gyrecognized (Crooksa, et al. 2004). To preserve this urban diversity and proceed in a more sustainable manner it is necessary provide tools that allow ecological principles to be incorporated in the planning process (Leitao & Ahern, 2002).
Introduction Relatively little is known about the biodiversity of Dublin s urban fabric Birds are useful indicators of biodiversity Bird Watch Ireland s garden bird survey covers an 11 year period of intense urban development
Questions What is the diversity of birds in Dublin gardens? Are there any trends in bird distribution and species assemblages between 1994-2005? Which species are the most frequent and widespread?
The Garden Bird Survey Dublin subset of Bird Watch Ireland s Garden Bird Survey: total of 787 addresses participated Winter survey over 11 years (1994-2005) The maximum number of birds of any given species observed during a 13 week period is reported Ancillary data: size of garden, type of garden Analysis whole country dataset published: (Crowe, 2005)
Dublin s bird diversity 88 out of 106 bird species nationwide can be found in Dublin Mean number of bird species reported per garden is 12.15 vs.18.9 nationwide. 19 species were reported only once during the 11 year time period (e.g. Canada Goose, Kingfisher, Hen harrier, Little Egret).
Temporal trends Total number of species/ year num umber of sp pecies 70 60 50 40 30 20 10 95 94 96 98 04 02 99 00 03 01 97 After 97-98 98 species numbers plateau at about 60, despite the number of participants fluctuating between 219 and 337 0 0 100 200 300 400 number of addresses
Temporal trends Mean number of species/garden per year 16 cies/garden Mean number of spe 14 12 10 8 6 4 2 94 95 96 97 98 99 00 01 023 03 04 After 97-98 98 mean species numbers plateau at about 12, despite the number of participants fluctuating between 219 and 337 0 0 2 4 6 8 10 12
Temporal trends Species assemblage: did species rank order (based on the number of addresses reporting the species) change over time? Kendall's coefficient of concordance (W) - gives a percentage concordance of species rank order over time W= 0.94 no change over time 17 species were consistently ranked within the top 20 reported species for each year
Most widespread species 100 Dublin Nationwide 90 Blackbird Robin 80 Robin Blackbird 70 Blue Tit Blue Tit 60 Magpie Chaffinch 50 40 30 20 % of addresses reporting 10 0 Blackbird Chaffinch Song Thrush Blackcap Long-tailed Tit Bullfinch Grey Wagtail Linnet Pheasant Waxwing Jay Buzzard Barn Owl Garden Warbler Can ada Goose Hen Harrier Little Egret Whitethroat Species
Discussion\ Conclusions What can be said about garden survey? Are these data reliable? How different is Dublin from the rest of Ireland? What can be said about the widespread d species are they particularly adapted to urban environment? Do they prefer certain food?
Future work Use garden bird survey to correlate occurrence of birds with urban habitat features Use other datasets (e.g. bats, lizards) to assess overall diversity pattern in Dublin Develop recommendation to planners concerning biodiversity in Dublin (together with the team)
Future work
Questions??
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