Oxford Partnership Blog

Submission by Stephen Harris, curator of the Oxford University Herbaria.

A herbarium is a collection of pressed, dried plants, and is a fundamental conservation tool. Herbaria are central to the initiatives to catalogue plant life on Earth, the debate about the future of global plant biodiversity and its conservation and understanding plant evolution. There are many herbaria scattered around the world, and may contain a few thousand specimens to more than ten million specimens.

A herbarium specimen comprises the dried plant and, importantly, the label. The label indicates when and where the specimen was collected, together with the plant’s ecology. Thousands of people have collected, thousands of specimens in some of the world’s most remote regions. Each specimen is therefore a record of when and where a particular plant was found but also a historical document. When many herbarium specimens are analysed together it is possible to state where species are distributed and how their distributions have changed over time. Herbarium specimens are also important for correctly naming plants. Furthermore, it is possible to extract pollen and DNA from herbarium specimens, study anatomy and even carbon-date them. Herbarium specimens can be used in ways that the original collectors would have found impossible to conceive. Free from damp, fungi and insects herbarium specimens will survive for hundreds of years. In Oxford University Herbaria we have specimens that were collected in the first decade of the 17^th century by an Italian monk; these specimens are so well preserved they could have been collected only a few years ago.

Oxford University Herbaria has been concerned with biodiversity issues, in various guises, for nearly four centuries. Established in 1621, the Herbaria had its roots in the Oxford Botanic Garden, and is the oldest herbarium in the United Kingdom and the fourth oldest such collection in the world. Oxford University Herbaria contain c. 1,000,000 specimens collected from around the world. Some of the species in the collection are now extinct; whilst other might be known only from the single specimen stored in the cupboards. Today, the collections and the data that they contain are being made available on the web through the botanical research and herbarium management data base BRAHMS online.

Captions

An example of a herbarium specimen collected in Mexico in 1992. This specimen was used to describe a new species in the genus Leucaena (see http://en.wikipedia.org/wiki/Leucaena). The genus includes about 30 species of woody plants, mostly small to medium sized tree. Some species of Leucaena are widely planted in the tropics and subtropics as multi-purpose trees – fast growing, used for firewood, animal fodder, fencing and so on.

Sturt's desert pea, collected by the pirate William Dampier (see http://en.wikipedia.org/wiki/William_Dampier)  in western Australia in 1699 is one of the many historic specimens stored in the Oxford Herbaria. This was 50 years before the Swedish botanist Carl Linnaeus developed the species naming science now uses. Before this time, all plants were named with phrases in Latin as seen on this specimen. Sturt's desert pea is the national flower of western Australia.

One of the objectives of the plant diversity research group at Oxford University is to catalogue data that describe which species of plants occur in different localities.

One of these activities is the development of a networked computing system known as BRAHMS (Botanical Research And Herbarium Management System).

BRAHMS is a data gathering and processing tool that encourages projects in different countries to assemble details about their local floras into a central data store. These data can then be used for many different purposes. Examples are producing species distribution maps; evaluating meaningful species diversity indices for different areas; pinpointing geographic areas that seem to be very rich in species; and highlighting areas that have been rarely or never visited by botanists.

During the last 12 months, training courses on how to use BRAHMS and the data it stores have been held in Brazil, Georgia, Ghana, Madagascar, Malaysia, South Africa and Vietnam. Botanists, ecologists and others on these courses learn how to manage and make greater use of the botanical data available in their own countries and how to speed up capturing yet more data.

The most recent course was held in February 2010 in Antananarivo, the capital of Madagascar. Madagascar, the world’s fourth largest island, has one of the world’s highest rates of plant endemism. Of the approximately 10 – 15,000 plant species found here, as many as 80% are found only on this island.

The development of BRAHMS and the running of associated training events is greatly assisted by the IHG Global Hotspot Initiative.

Denis Filer

Globally, there are 8 recognised species of baobab tree and of these, 6 are only found on Madagascar including the species Adansionia ze shown here. Read more on http://en.wikipedia.org/wiki/Adansonia. Foto provided by Stuart Cable who coordinates RBG Kew’s Madagascar projects.

Some of the luxuriant littoral forest vegetation in the Southeast of Madagascar showing stilt rooted Pandan (screw-pine) trees (http://en.wikipedia.org/wiki/Pandanus) and large leaved aroids (http://en.wikipedia.org/wiki/Araceae) – relatives of common European house plants like Monstera and Philodendron. This Pandan species is found only in this part of Madagascar. Foto provided by Stuart Cable.

A few of the participants of the Madagascar BRAHMS training course February 2010 learning how best to assess plant diversity for different regions of the country.

In daily conversation, “hot-spot” refers figuratively to a place where a particular activity, danger or other phenomenon peaks. To connect to the internet in town, find a wi-fi hot-spot. Scientists have adopted this evocative phrase in various guises. To a geologist, a hot-spot is a region where volcanoes are common, for instance.  Maps of hotspots are often used to help prioritise relevant activities. So, crime hot-spots are areas within which we might expect the police to be particularly vigilant.  Biodiversity hot-spots are therefore used and keenly debated by conservationists.

To conserve hot-spots, we need to know at various map scales where, precisely, they are. We particularly need maps at a scale where management is practical. There’s limited value in stating only that “the  Andes” or “Japan” is a hot-spot, even if global conservation agencies can use this information to apportion global funds. This global scale is in fact the only level for which biodiversity hotspots are well publicised, but these are certainly not areas where conservation  plans can be focused and manageable. Conscientious developers cannot use this information to plan more sustainable developments, for instance. Also, the list of hot-spots even at the global scale is not yet exhaustive.

We need biodversity hotspot maps at local to regional levels, so how should we calibrate the standard “biodiversity thermometer” and ensure that it can be used at various scales? What is it about biodiversity that is at particularly high levels in the hot-spots exactly?  Different scientists interpret the concept of biodiversity hotspot slightly differently. Some include threats to the habitat in the equation; some count species, others count only species unique to the region in question, and so on.

We have over the last 20 years been using and developing a standardised biodiversity thermometer for hotspot detection. Our thermometer measures an attribute we call bioquality on an index we call the Genetic Heat Index (GHI). The GHI can be applied consistently at all scales. Using this, and standardised sampling methods, we are making systematic measurements of GHI around the world, mapping global bioquality at all scales. We also aim to make such thermometers – i.e. sampling and measuring tools – more widely available. Gradually, the global and local pattern of hot-spots should emerge, allowing resolution of hot areas even on the scale of your own back garden, and potentially measurable by you, armed only with a field-guide and some standardised guidance. This will give us a means to monitor impacts on biodiversity at a practical level, and this is one or the research goals that IHG is helping us achieve.