We don’t know what pollinates most Australian plants.

Australian flowering plant diversity is legendary. Within an hour trip outside of our major metro centres anyone can quite easily witness unique Australian plant diversity in subtropical forest (Brisbane), grassland (Melbourne), and sandstone heath (Sydney). The diversity close to home is fairly well catalogued, and while it is hard to discover a new plant species, merely spending time around our native plants is very likely to reveal something that has never before been documented.

Something like 90% of our native plants rely on animals for pollination in order to set seed. Despite this, we simply do not know what pollinates most of our Australian native plants. The fact that the private lives for many of our native plants remains mysterious is due to their great diversity and the limited time and resources available to document what’s going on every day in the bush.

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Two native bees (Hylaeus (Rhodohylaeus) sp.) visiting flowers of the Broom Bush (Eremophila scoparia) in Western Australia.

And these uncharted interactions are totally critical for the functioning of our native ecosystems. Pollination underpins production of seed for the next generation, builds seed banks for post-fire regeneration, and also produces fruits and seeds that are critical food resources for our native animals.

Our ignorance of native pollination networks is therefore vastly out of step with their importance. This is illustrated in the example of bee declines, where we have all heard about the threats impinging on honeybees and pollination service for food crops, yet when it comes to Australian native bees, we lack the basic benchmark data needed to make a solid judgment about whether they too are declining*. It is therefore imperative that we commit effort to recording native pollination networks now, before they are lost to us. While it is hard for long term ecological monitoring projects to attract funding, ongoing development of automated imaging of flower visitors and large scale citizen science projects offer some promise for increased capability in filling this ecological blind spot.

But our ignorance here can also be thrilling. This means that every time you are in the bush, and witness an insect or bird taking nectar or pollen from a flower, there is a reasonable chance it has never been documented before. In my work with University of Melbourne I have been studying several native shrubs to understand their pollination, and for many of these species, it is gratifying to know that my work will be the first documented evidence of what is visiting them. But you don’t have to be a trained scientist to do this, you just need some patience, luck, and some fine weather. And while discovering and photographing an unusual native bee pollinating one of our native flowers won’t win you a Nobel Prize, I guarantee it will provide any enquiring mind with a hit of electric discovery every single time.

 

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Photographed on Mount Buffalo, Ken Walker (Victoria Museum) later identified this bee as the very rare Lasioglossum (Callalictus) callomelittinum. Few photos of it exist. This individual is buzz-pollinating a Fringe Lily (Thysanotus tuberosus).

 

Links for pollinator observations:

Bowerbird: Nature observations database

Wild Pollinator Count

Government pollinators repository

*But given native bees need native habitat, and native habitat is being cleared at astonishing levels, we can, with a high degree of confidence, say that native bees are declining too.

5 thoughts on “We don’t know what pollinates most Australian plants.

  1. Great post! One of the things that made me start to question whether the traditional pollination syndromes were a useful framework for understanding the diversity of plant-pollinator interactions was my trip to Australia in 1993/94. It was clear that many of the flowers I was seeing did not fit the typical models or expectations, and no one knew what was pollinating most of these plants.

    However Australia is not unique in this respect; I estimate that we only have documented pollinator data for _any_ kind for about 10% of the 352,000 species of flowering plants around the globe, and whole genera and families are not studied. So any records are potentially very useful.

    Look forward to getting back to Australia at some point!

    • Thanks Jeff! Interested to know whether your 10% is a quantified estimate or a feel for the literature. Thinking about this post has me trying to think of ways to actually measure what proportion of species have accessible reported pollinator data. For example, automated literature scraping for names in The Plant List and keyword “pollinat*”?

      As for a global perspective, you’re totally right, and here I was pretty much writing for an Australian audience. Aussie plants might even be better studied than other biodiverse regions in Africa, Asia and the Neotropics.

  2. The 10% figure is an informed estimate that comes from some recent thinking on the topic that I’ve done for the book I’m currently writing. I’ll summarise it here.

    The paper on Apocynaceae pollination systems that we published in the summer was able to pull in reasonable-to-good quality data for a little over 10% of the described species in the family. By coincidence a similar piece of work I’m doing on another family with an Argentinian postdoc also found a sample of about 10% of species with data on pollinators.

    Some smaller clades of plants have been much better studied, e.g. the c. 280 species of penstemons have data available for 49 species or 17.5% (Wilson et al. 2006); pollinators are known to at least fly family level for about one third of the c. 200 Ceropegia species (Ollerton et al. 2009, 2017); whilst the genus Dalechampia has been intensively studied by Scott Armbruster who has pollinator data for about two thirds of the 120 species (Armbruster et al. 2009).

    Of the super-large families, orchids have been well studied but no one has brought together the scattered data in recent years to provide a summary, whereas the daisy family is really not well studied, probably because of the high number of generalists which are somehow seen as less interesting than the specialists. But for both of these I’d be amazed if we had data for more than 10% of species.

    How we assess this rigorously is something that I’ve also thought about. Data scraping the literature would be a way to get some information, but it’s going to miss a lot of the earlier literature. Then there’s gray literature and unpublished data. Plus network studies have a lot data in them but not necessarily in a format that’s useful for an exercise such as this. Crowd-sourcing might be a better approach in which specialists on particular groups/regions are asked to contribute their knowledge via a website. If you want to take this further and initiate a project, count me in!

    • Interesting…. and I’m just about to leave for a field trip, so don’t have time for a detailed reply. But asking specialists sounds eminently sensible! And saves work! I’m not starting new things for the moment, but should I manage to get some continuity, this is something I’d like to revisit.

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