Monthly Archives: November 2012

When is a yucca not a Yucca?

Notice the difference?  The italicisation and capital initial of the second Yucca.  That’s how the genus name of a species should be formally presented in a scientific paper, or in a newspaper article, or wherever.  Like Homo – the genus in which our own species (Homo sapiens) sits.

It might seem like a narrow and pedantic point, but it’s important.  Accurate and descriptive naming of species, genera, families and other taxonomic ranks is crucial to those of us who study biodiversity and is at the core of our science: without names for species, for example, we cannot make informed conservation judgements or comparisons between habitats in relation to which species are present or absent.  Names matter.

But it’s not just the names themselves, it’s also how they are presented which is important:  when I see the words yucca and Yucca in print, they signify two different things to me.  The word “yucca” is an informal name for a group of plants that is widely applied by gardeners and has no formal scientific status.  Yucca on the other hand refers to a very specific group of plants and has a clear meaning to a biologist.

To give you an example of this I’ll first have to introduce you to the Northamptonshire Natural History Society (NNHS) which was founded in 1876 and must be one of the oldest surviving local natural history societies in the country.  Some important 19th Century scientists were honorary members, including Charles Darwin, Thomas Huxley and Joseph Hooker.  This perhaps reflects Northampton’s proximity to London though there may be other factors: one could compile quite a long list of scientists with links to Northamptonshire.

The Journal of the Northamptonshire Natural History Society was first published in 1880 and continues to the present day.  Which brings us back to yuccas.  Last year a short article by a NNHS  member summarised the local weather conditions in Northampton for each month of 2010 (J. Northants Nat. Hist. Soc. vol. 45, no. 1).  December of that year was a particularly cold month and the author notes that “the species of Yucca trees planted in Northampton, which although thriving in recent years, were killed by the cold period”.

Strictly speaking Yucca refers to plants of a particular group which are endemic (i.e. only naturally occurring) to the New World.  The genus Yucca is a member of the asparagus family (Asparagaceae), subfamily Agavoideae.  The plants which suffered so much in the cold winter of 2010 are in fact New Zealand Cabbage Trees (Cordyline australis) which, as the name suggests, are endemic to New Zealand.  The genus Cordyline is also a member of the family Asparagaceae but belongs to the subfamily Lomandroideae and is therefore only distantly related to Yucca.

The leaves and stems of Cordyline and Yucca do look very similar, hence gardeners tend to use yucca as an informal name for both.  However when these plants flower it is clear that they are very different.  Flowers of the various species of Yucca are typically quite large and are adapted to pollination by a very specialised group of moths which lay their eggs within the flowers.  The reward for these moth pollinators is a brood site for their caterpillars, which feed on a proportion of the developing seeds of the Yucca plant.  In contrast the flowers of Cordyline australis are small and produced in very large numbers in dense inflorescences.  They are also highly fragrant, to which anyone who has grown one of these plants to maturity in their garden can testify.  The fragrance attracts a range of insects which feed on the nectar produced by the flowers and so pollinate them in the process.  It is these differences in flower structure, more than characters of stems and leaves, which taxonomists use to classify such plants.

Until recently large New Zealand Cabbage Trees were a feature of many front gardens across Northampton.  Some particularly fine examples were to be found along the Kingsthorpe Road between Osborne Road and Balmoral Road.  I suspect that the largest Northampton specimens were planted in the 1970s, perhaps because people wished to recreate something of the exotic feel of package holidays to Spain and Portugal.  Following the freezing weather of December 2010, the growing tips of most of Northampton’s New Zealand Cabbage Trees were killed and the top growth gradually withered and died.  I was sad to see this happen to my own plant, a medium-sized specimen that I had rescued from a skip at the University several years ago, and which had become well established in my garden.  However later in 2011 my plant, and those in neighbouring gardens, re-sprouted from its deep tap root and started to produce multiple rosettes of leaves around the base of its dead trunk.  Give it a few years and Northampton gardens will once again be crowned by these exotic imports from the Southern Hemisphere.  I moved house in early 2012 and wasn’t able to take my rescued plant with me, but I have a feeling it will survive many more cold winters to come.

Names matter to biologists, indeed to scientists of all types.  They signify and tell us things beyond just the words themselves.  To give a very personal example, a few people have asked me why I chose the title “Professor of Biodiversity” rather than “Ecology” (my main area of training, though confused in some peoples’ minds with New Age philosophies); or “Biology” (a much broader designation than I feel comfortable with); or even “Pollination Ecology” (narrow, to the point, but too restrictive).  After a LOT of thought I chose “Biodiversity” because it very broadly reflects my interests in the whole of Earth’s life forms, the interactions between these species, and how they come together as assemblages, communities and ecosystems.   But I’m also interested in the history of our understanding of biological diversity and this title gives me scope to pursue those interests too.

It’s all in the name.

The Great eSCAPE

As I begin to write this blog entry, there’s a buzz of voices around me, excitedly discussing future research or past results, or saying goodbye to friends and colleagues, old and new.  It is the last day of SCAPE 2012, the annual meeting of the Scandinavian Association of Pollination Ecologists (or “for Pollination Ecology” or “for Pollination Ecologists” – the name seems to have drifted over the years).  SCAPE was the first overseas conference I attended, as a young and enthusiastic PhD student, in 1991.  Older but no less enthusiastic, SCAPE is for me a regular fixture in the calendar.  Even if I can’t always attend, I try to send my good wishes to the organisers, with a promise to be there the following year.

SCAPE was founded in 1986 as an informal get together of Swedish research students who were all broadly interested in questions of pollination ecology.  Since then it has been held every year, maintaining the informal organisation and circulating between Sweden, Denmark, Finland and Norway, which is the venue for this year’s meeting in Skjærhalden in the beautiful Ytre Hvaler National Park.  Attendance in recent years has varied between 50 and 80 participants, peaking when it’s one of the 5 yearly anniversary specials.  One of the many great things about SCAPE is that it’s a very friendly, open hearted conference at which new research students rub shoulders with established researchers, and can present their provisional research findings safe in the knowledge that they will receive constructively critical feedback.  Those established researchers can expect to have their conclusions challenged, as good scientists should, but it’s never done with malice.

The talks this year have spanned the usual wide range of geographical localities (Brazil, Israel, Spain, Ireland, as well as Scandinavia), scales of research focus (from the genetics of self incompatibility to landscape scale assessments of pollinator diversity), and quality of presentations (overuse of laser pointer on text-dense slides to textbook examples of how to deliver a message in 15 minutes).

Although I enjoyed the whole meeting and gained new knowledge from every presentation,  there have been some talks which really stood out for me because I appreciated the overall approach, the message that was being delivered, or the insights it gave into questions I’d not previously considered.  These include Dara Stanley’s estimate that bumblebees from 800 different nests were foraging on a single field of oil seed rape; Achik Dorchin’s account of the staggering number of bee species in small habitat fragments in Israel (totalling more than in the whole of Britain); a dissection of the question of when pollination can be a limiting ecosystem service for crops by Ignasi Bartomeus; and Robert Junker’s initial account of the huge diversity of bacteria associated with different flower organs.   There were many others I enjoyed, of course, but that gives a taste of how diverse the subjects were.

Although I wasn’t speaking this year, two members of my research group were:  André Rodrigo Rech talked about his PhD work on pollination of Curatella americana in Brazilian savannahs; and Stella Watts presented some of her postdoctoral work on honey bee versus unmanaged bee pollination in an endemic Iris species in Israel.  This last work was undertaken with Amots Dafni, one of the doyens of pollination ecology.  Amots attended the conference and told us he’d finally decided, in his 68th year, to retire from formal university teaching, administration and supervising research students – and begin a new project!  Enjoy your “retirement” Amots!

Karin attended SCAPE with me and enjoyed scientist-watching, a hobby that gives me frequent insights into how we work as a community, and gives her insights into what makes me tick.  Half a day of travel saw us back home at 2am Monday morning; I then had to be in university for a 9am seminar with students on my final year Biodiversity & Conservation module.  Despite being tired the seminar went well, perhaps fuelled by the post-conference buzz I usually feel after these events.  The seminar finished early to enable me to drive up to Park Campus, the university’s other site, for a brief  meet-and-greet with the head of Sandtander Universities and his team.  Banco Santander’s higher education arm has been funding scholarships and research activities at the university for several years now and it was a small grant from them that enabled André to attend SCAPE.  Seemed only polite to say thank you.

A highlight later that week was Thursday, which was taken up with our annual first year undergraduate trip to Oxford Botanic Garden, part of my module Biodiversity: an Introduction.  I also wrote about this in March but for the current academic year we have brought the trip forward.  Our visit  was hosted by the superintendent, Timothy Walker, who engaged the students for an hour as we walked the gardens, covering everything from the medical importance of plants such yew trees (Taxus spp.) in providing treatments for cancer, to the importance of specific trees for two Oxford writers, JRR Tolkien and Phillip Pullman.  Timothy also described how much of the planting is laid out in beds according to plant families as defined by the latest phylogenetic research the (APG III system) stressing the importance of modern systematics to understanding biodiversity.  If you want to know more about this, Timothy wrote and presented a recent television series called Botany: A Blooming History which remains the best account I’ve seen of the history of plant taxonomy and why it is relevant to modern plant sciences.

That evening Karin and I attended the opening of a show at the university’s gallery called “Encounters with Drawing” by artist Angela Rogers.  There’s some very thought provoking material in the show and I recommend a visit if you are local and have time – it runs until 30th November.  We chatted with Angela about the “drawing conversations” she has with people and some of her comments about “how much space do individuals need” chimed with familiar ideas from ecology about intra- and inter-specific competition in organisms and niche theory.

I’m going to end this entry with a link to a video post by my friend K.-D. Dijkstra (who I introduced in an earlier blog).  It’s not often that the actual moment that a species new to science is discovered gets captured for everyone to see, but here’s K.-D. doing just that!