The impact of building a new university campus on urban bird diversity and abundance: a seven-year study

Over the past few years I’ve posted several pieces about how colleagues, students and myself have been monitoring one aspect of the environmental impact of the University of Northampton’s brand new 22 ha, £330 million Waterside Campus development.  Specifically we have been looking at how the construction work has affected bird diversity and abundance in and around the site: see my posts “An interim report on the Waterside bird surveys” and “Monitoring the impact of the new Waterside Campus“.

Our approach has been to repeat the baseline bird surveys (three winter and three spring) that were done in 2012/13 as part of the environmental impact assessment prior to work taking place.  The new campus opens this summer and, following our most recent set of surveys in April/May, it’s time to reveal our findings so far.  Here are the headlines:

The baseline surveys recorded a total of 52 bird species.  In the following graphs birds have been categorised according to their RSPB Red, Amber, Green status.  Four species from the original surveys remain unrecorded:  Marsh tit, Bullfinch, Collared dove, and Lesser whitethroat.  However at least two of these (Bullfinch and Collared dove) are still found within 1km of the site.

During the repeat surveys we have recorded an additional 25 species that were not found in the baseline surveys.  This is not surprising – bird assemblages are dynamic, given that most species are very mobile – but it’s still interesting to find that so many more species are finding homes in the area.  If the four “missing” species return then the potential full diversity of the site is at least 77 species:

However this overall good news story is more complex than it first appears.  In the graph below I have plotted the Simpson’s Index for each survey, with a LOESS regression showing 95% confidence limits.  Simpson’s Index combines the data on both the number of species and their abundance to provide an overall measure of the impact of the construction work.  It’s clear that during the main phase of construction the average bird diversity per survey dropped significantly.  Following the completion of the noisiest and most disruptive activities, diversity has started to return to its pre-construction levels:

This overall assessment hides a lot of detail; as you can see below, Green status birds have fared best, Amber status birds have done ok; Red status birds have fared worst, especially in spring, but better in winter:

The bird diversity is not quite back to what it was, but overall our findings are very encouraging.  In the initial phases of the development we talked with the landscape architects about adding ecological value to Waterside by including more native trees, reed beds, wild flower meadows, etc.  We’ve yet to assess how these features will affect biodiversity on the site, including birds, but we might predict that the final diversity exceeds that of the original brownfield site.  With that in mind we will be doing at least one more cycle of three winter and three spring surveys during 2018/2019.

Long-term monitoring of this kind is almost never undertaken for infrastructure projects of this nature. Universities, I would argue, need to take a lead in promoting such activities and making then a common component of the planning process.  From this work I think that our main conclusion is that redevelopment of peri-urban brownfield sites such as this doesn’t have to mean a loss in biodiversity, at least not as far as the birds are concerned.  We also plan future surveys of mammals, plants and invertebrates to assess how they are doing.

My thanks to all the colleagues and students who have been involved in the work so far: Duncan McCollin, Janet Jackson, Joanne Underwood, Kirsty Richards, Suzy Dry, Charles Baker, Pablo Gorostiague, Andrew Hewitt.

To finish, here are some photographs that we took of the work being carried out so you can see the scale of what has been achieved at Waterside: