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Monday, 17 November 2014

Green roofs part II: lofty havens for wildlife

By Helen Roberts

The green roof industry has been aided over the past few years by an unlikely character. The black redstart (Phoenicurus ochruros), a robin-sized bird of strange habits, has not only helped draw attention to the green roof industry, it has advanced development of green roof design.

The black redstart is unusual in its call, looks and ecological preferences. Its song starts with a hurried warble followed by a sound similar to that of scrunching of a bag of marbles. Males have a fiery red tail and the species has a propensity to hang out in industrial places.

Within the urban environment, brownfield sites can be rich in biodiversity and can be lost when they are developed. The story of the black redstart is inextricably linked to that of humans and urban centres. Black redstart population numbers have fluctuated in the urban environment due to human activity, and this is where the story of the black redstart has impacted the green roof industry in a positive way.

During and after the Second World War the black redstart population soared because bombsites provided a habitat that closely replicated their preferred habitat found on the scree slopes of the Alps. With redevelopment of areas of London, however, populations declined. Other cities also saw a drop in numbers as a result of development.
Laban Dance Centre in London.
Credit: rucativava,
CC-BY-SA-2.0, via Wikimedia Commons

Deptford Creek in London, an area that was earmarked for development, was important for its populations of black redstarts. The developers were pushed by wildlife groups to provide suitable habitat for the birds through the implementation of green roofs. This truly innovative solution to mitigate the decline in black restart populations led to the development of green roofs designed specifically for black redstarts. The rubbleroof of the Laban Dance Centre in London, installed in 2000, was the first of these in the UK. Rubble roofs, such as the Laban Dance Centre’s, replicate the features of a brownfield site and often incorporate materials from the original site. They have a mix of aggregate materials such as crushed brick and concrete, stones and boulders. The Laban Dance Centre roof also incorporates features such as logs and sand boxes in order to study nesting bees. It has been monitored since 2002 and a number of rare invertebrates have been recorded using the habitat.

Numerous studies have shown that green roofs help support several Red Data book invertebrates and UK Biodiversity Action Plan species such as the brown-banded carder bee (Bombus humilis) and the nationally scarce Bombardier beetle (Brachinus crepitans) and that these green roof conditions can be replicated at other sites.

The right plants for the right roof


Incorporating the right plant species in to the design of a green roof is important for achieving biodiversity objectives. Simple sedum matting has been shown to have little ecological benefit for invertebrates, though they do provide sources of food for foraging bees in summer.

A truly exemplar green roof that is rich in plant species is the Moos Filtration Plant in Zurich, which cleans all the water for the inhabitants of Zurich. Yet, this green roof came about by chance as there was no original intention to create a green roof as part of the building design. When the filtration plant was built, the multiple roofs were covered in exposed waterproofing which subsequently caused the water below the roof deck to become polluted with bacteria due to high temperatures during the first summer. In order to moderate the temperature of the roofs, a 5cm sand and gravel layer was laid down followed by a layer 15-20cm deep of local meadow topsoil. This soil was teeming with flower and grass seed and it became a flourishing 30,000m2 meadow. Today these expansive roofs provide habitat for 175 species of plants, many of which are rare and endangered at a local and national level, including 14 species of orchid. The roofs now have special protection under Swiss nature conservation laws. 

Due to the pressures of habitat loss through urbanisation, it is becoming increasingly important for biodiversity to be retained. If land is lost at the ground level through building, then green roofs help provide stepping stones above for wildlife and can provide valuable habitat for flora and fauna that would not ever be found on a conventional roof. 

Monday, 10 November 2014

Botanists disperse some 'big data'

Recently, Botanists at Trinity College Dublin launched a database with information that documents significant ‘life events’ for nearly 600 plant species across the globe. The database is the result of contributions from individuals working across five different continents, who compiled information on plant life histories for a near 50-year span, and is an example of big data.

What is ‘big data’?
Black pine (Pinus nigra), one of the species whose life
history data is part of the database, is seen against a
stunning backdrop of New Zealand. Credit: Yvonne Buckley.

In academic circles, the buzz-term across all disciplines seems to be ‘big data’, and it means exactly what it sounds like – a whole lot of information. More formally, of course, big data refers to data sets that are so large and complex that traditional methods of processing the information contained within them simply aren't adequate. Big data draw upon many sources of information and represent a body of work that far exceeds what a single researcher, or indeed an entire research group, could gather in their careers.

While there are many challenges of working with big data – storing it, analysing, visualising it and ensuring its integrity to name a few – the benefits of working with such large data sets may make overcoming these challenges worthwhile. Repositories of such vast amounts of information can not only help foster collaborations, but they can be used to answer questions surrounding some of the most complex and pressing issues society currently faces, including climate change, food security, and mass species extinctions.

Of course, what is considered to be big data today will not be big data tomorrow as our management systems and computing capacity improve. This is the inevitable path of technological advancement; the Human Genome Project took over ten years (1990-2003) to sequence the human genome and now it can be done in a day for a fraction of the cost.

The importance of sharing knowledge
Plantago lanceolata at Howth Head, Dublin, Ireland - one of
the near 600 plant species that researchers have gathered
extensive life history data on. Credit: Anna Csergo.

The researchers at Trinity have made their database, called COMPADRE, freely available in the hope that other scientists access the information to advance their research. The size of the database means it can be used to help answer an infinite number of questions – such as how plant communities may respond to climate change or physiological processes that might provide insights into our own aging and health.

“Making the database freely available is our 21st Century revamp of the similarly inspired investments in living plant collections that were made to botanic gardens through the centuries;” said Yvonne Buckley, Professor of Zoology at Trinity’s School of Natural Sciences, “these were also set up to bring economic, medicinal and agricultural advantages of plants to people all over the world. Our database is moving this gift into the digital age of ‘Big Data’.”

The approach of free knowledge sharing is becoming more common and is a critical step toward resolving some of our biggest challenges. The University of Bristol’s Cereal Genomics Group has made the wheat genome along with hundreds of thousands of molecular markers freely available through their searchable database CerealsDB. These data can be used in wheat breeding programmes to develop new varieties of wheat that are more resistant to disease or droughts or produce higher yields.


Our best chance of overcoming some of the global challenges of the 21st Century is to work together. Sharing knowledge through databases, such as COMPADRE and CerealsDB, will ensure every scientific contribution counts towards this united effort.