across Dublin city Urban Environment Project Michael Brennan, Tom Hayden, Tamara Hochstrasser

Transcription

1 Variations in bird diversity across Dublin city Michael Brennan, Tom Hayden, Tamara Hochstrasser Ub Urban Environment tproject t( ( School of Biology & Environmental Science, UCD Urban Institute Ireland, UCD

2 Introduction Outline Questions: what do we want to know? The Garden Bird Survey Answers Discussion Conclusion Future work

3 Introduction The ( 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.

4 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).

5 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

6 Questions What is the diversity of birds in Dublin gardens? Are there any trends in bird distribution and species assemblages between ? Which species are the most frequent and widespread?

7 The Garden Bird Survey Dublin subset of Bird Watch Ireland s Garden Bird Survey: total of 787 addresses participated Winter survey over 11 years ( ) 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)

8 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 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).

9 Temporal trends Total number of species/ year num umber of sp pecies After species numbers plateau at about 60, despite the number of participants fluctuating between 219 and number of addresses

10 Temporal trends Mean number of species/garden per year 16 cies/garden Mean number of spe After mean species numbers plateau at about 12, despite the number of participants fluctuating between 219 and

11 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

12 Most widespread species 100 Dublin Nationwide 90 Blackbird Robin 80 Robin Blackbird 70 Blue Tit Blue Tit 60 Magpie Chaffinch % 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

13 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?

14 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)

15 Future work

16 Questions??

17 References A. Botequilha Leitao, J. Ahern. Applying landscape ecological concepts and metrics in sustainable landscape planning. Landscape and Urban planning. 50 (2002) K. R. Crooksa, A. V. Suarezb, D. T. Bolgerc. Avian assemblages along a gradient of urbanization in a highly fragmented landscape. Biological Conservation 115 (2004) O, Crowe. The Garden Bird Survey: monitoring birds of Irish gardens during winters between 1994/95 and 2003/04. IrishBirds (2005) 4/3/06 Page 29 E. FERNÁNDEZ-JURICIC1 and J. JOKIMÄKI. A habitat island approach to conserving birds in urban landscapes: case studies from southern and northern Europe. Biodiversity and Conservation 10 (2001) U.G. Sandstr om, P. Angelstam, G. Mikusinski. Ecological diversity of birds in relation to the structure of urban green space. Landscape and Urban Planning 77 (2006) World Urbanization Prospects: The 2005 Revision, Population Division, Department of Economic and Social Affairs, UN