Biological Flora goes global!

Journal of Ecology has been publishing in-depth Biological Flora accounts since 1941. However, these have previously focused on plant species native to the British Isles. This month we publish our first ever International Biological Flora account, for Nervilia nipponica!

Our Biological Flora Editor, Anthony Davy, shares more about this momentous international account and shares his reflections on the 80 year anniversary of the Biological Flora series.

For the last 80 years, readers of the Journal of Ecology have been accustomed to finding detailed ecological accounts of British and Irish plant species, in a comfortingly standard format, tucked away at the back of their issues. Now, with the July 2021 issue, we are delighted that the scope of the Biological Flora project has been dramatically expanded. The inauguration of an International Series means that an account of any plant species in the world can potentially be included.

This opens the door to at least 390,000 species – nobody knows precisely how many of course. “Ambitious” I hear you say, particularly as we have published a more modest 296 accounts of rather more than 300 species in the first 80 years! A joke from my youth about the project not keeping up with the rate of evolution has certainly come back to haunt me as an editor.

Clearly it is neither possible or desirable for the Journal to cover more than a tiny fraction of these species and we will need to be highly selective. It does, however, provide a long-overdue platform for highlighting plants of global interest, while at the same time engaging with a broader spectrum of authors and readers. The format is the same as for the British series, except with an additional section on ‘Global heterogeneity’.

The first international account is of an unassuming little orchid, Nervilia nipponica (mukago-saishin). It is the product of nearly 20 years’ work by lead author Stephan Gale and his colleagues at Makino Botanical Garden and other institutes in Japan. When they started, N. nipponica was classified as Critically Endangered, endemic to Japan, and with a total global population of no more than 100 individuals. Subsequently they discovered additional populations that made its status rather more secure than previously feared, including in South Korea, which also meant the species had to shed its endemic status.

Flowering spike of Nervilia nipponica. Photo: Stephan Gale.

The team set out to produce a full picture of the species’ biology after an unusually large population had been discovered along the route of a planned new highway – the Ministry for Land, Transport and Infrastructure having been persuaded to fund their work. This involved not only science but also advocacy, as they gradually put the pieces together and reported the emerging picture to government. Happily, they were allowed to transplant many of the plants and safeguard the remaining ones from edge effects.

Nervilia nipponica is a small, stoloniferous, seasonally dormant herb that grows in the understorey of evergreen forests in the humid subtropical zone of central and western Japan, with a few outlying populations on Jeju Island in South Korea. Its northern extent is defined by the 0°C winter isotherm. It is a weak competitor that occupies species-poor microsites in which bare ground and leaf litter predominate. Plant numbers tend to decline as the ground cover of over-topping understorey vegetation cover increases.

The species has an unusual life cycle. Its inflorescence sprouts from a short-lived, subterranean tuber in late spring and leaf-flush does not occur until after fruit-set. Most tubers, however, do not flower in any one annual growth cycle. Long-term monitoring of individually marked plants suggests that tubers are resource-limited and that a flowering event constrains future growth.

Nervilia nipponica at the leafing stage. Photo: Stephan Gale.

Typically for an orchid, it depends on fungal associations. Mycorrhizal colonisation starts in the tubers and increases during the growing season to peak at the leafing stage. Stable isotope signatures indicate that the species is partially mycoheterotrophic, with the fungal partners supporting growth, particularly at lower light fluxes when photosynthesis is limited. Despite this, reduced light availability associated with forest succession can lead to population decline.

Populations tend to be small and prone to extirpation, but the species is probably under-recorded, because of its ephemeral emergence above ground and inconspicuous habit. Management interventions likely to benefit the species include thinning dense forest canopy and removing encroaching ground cover.

Stephan said ‘I started researching Nervilia nipponica as the first major, real-world project I took on as a professional botanist and ecologist, in 2003. Along the way, the genus Nervilia became my PhD topic. I never knew at the time how much this would end up becoming a part of my career and my life! I have lamented the fact that there was no international version of the Biological Flora for years, and I could not believe my luck when it was announced just as I had finally knuckled down to compiling all the disparate parts of the whole sprawling project.’ The luck is mutual – it was also timely for the series to have such an interesting account ‘oven-ready’ for its inaugural article.

Anthony Davy Biological Flora Editor

Read the full International Biological Flora account for Nervilia nipponica here.

You can search for and access all published accounts using the Biological Flora database.

If you’re interested in contributing towards our Biological Flora series, you can email your proposal to Anthony Davy.

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