Bee Blooms: The Australian Edition (Ep. 34)

This past spring has seen devastating flooding happening on nearly every continent. One country not immune to the disastrous effects of climate change is Australia. No person, animal or landscape can escape the consequences the climate crisis is bringing. Sometimes, the smaller the organism, the more crushing the damage. Climate change is impacting plant-pollinator interactions in Australia, leading to shifts in flowering times and the availability of floral resources. 

Today we’re joining Dr. Kit Prendergast on her journey to protect and preserve Australia’s native bees. She shares a wealth of knowledge and research to help us understand native bees’ ecological needs and the significance of maintaining diverse floral environments.

Dr. Kit Prendergast is a native bee ecologist who works as an ecological consultant, assisting anyone in need of a wild bee expert. She investigates the impact of honeybees on native bees and pollination networks, and the impact of urbanisation on native bees. Read her full study on bee hotels here and follow her research here.

Kit is such a fabulous promoter and supporter of bees. Her YouTube channel is buzzing, you can also follow her on Twitter, and check out her book, Creating a Haven for Native Bees.

Good to know

Another recent study Dr. Prendergast undertook involved looking a bit more closely at what native bees preferred to eat. Turns out, Australian and introduced bees prefer to visit and feed from native flowers and plants rather than exotic species. And native bees are particularly reliant on native flora. This is good information for people looking to create bee-friendly habitats in their gardens–native flowers and plants are what the bees prefer.

In case you missed it, Kit joined The Bee’s Knees in July 2023 to talk about bee hotels.

Transcript

[00:00:00] Welcome to the Bee’s Knees. I’m your host, Jacy Meyer. The Bee’s Knees is a podcast wild about native bees. Wild and native bees are under threat worldwide. In each episode, we look at actionable things we can do to support these adorable little guys whose pollination work is crucial for maintaining biodiversity.

Thanks for being here.

Planting flowers for bees sounds like a great and simple plan. Head to the nursery, pick up some seeds or blooms, plant them in your garden, sit back and welcome the bees. Unfortunately, though, it’s not that easy. Every environment has its own climate, which means what grows and lives there is dependent on that climate.

That’s why there aren’t many cacti growing naturally in Central Europe. In Australia, which has developed in isolation for thousands of years, the flora and fauna have co evolved, making the plant pollinator networks quite specialized. I’m pleased to talk today with Dr. [00:01:00] Kit Prendergast, an Australian native bee ecologist, who’s going to share with us the glorious bee world down under.

But first, Kit, can you briefly introduce the variety of habitats and climates found in Australia? Australia is a very big continent and we have a beautiful diversity of habitats and climates. I guess down in Tasmania, it’s. It’s almost, I guess, temperate New Zealand climate, it gets very cold, it can even snow there.

So, bees are only active for a shorter period of the year, um, you know, spring, summer months and like later spring, um. Yeah, it’s much colder there. There’s lots more conifers and the vegetation and climate is almost like New Zealand. Anyone is listening from New Zealand. And then, you know, we have the extreme in the middle of Australia where it’s desert.

And so you’ve got very dry [00:02:00] habitat, but when there’s rain, everything springs into action. Then in Victoria and the Australian Capital Territory, the ACT, again it’s more temperate and we can have snow in the tops of the mountains there. As we move up the coast, we get to northern New South Wales and then Queensland where it’s tropical and We’re hot and humid, we’ve got rainforest plants, and the rain mainly occurs in, um, summer, but with climate change, we’re actually having it all over the place.

Um, and then as you get up into Northern Queensland, across the Top End in the Northern Territory, and Northern West Australia again, it’s very tropical, and rather than your spring, summer, autumn, winter, you’ve got the dry season and the rainy season because it’s sort of always hot there, like always hot and the rains mainly occur in summer [00:03:00] and then the dry is in winter.

Then in southwest Western Australia where I’ve done most of my research, it’s got a Mediterranean climate where you’ve got hot dry summers and cold wet winters and you’ve got clear, much more clear seasons and The flowers really set off after the winter rains. And then you’ve got a great phenology of plants flowering at different times throughout the year.

And even in like the end of summer, you’ll have some mass blossoming eucalypts, which are really important. And the start of autumn is really the low flower season. So many different climates and plant phenologies that all of these are also being disrupted by climate change. So does planting native flowers in our gardens become more important in the face of climate change?

Yeah. So it’s not even just some native flowers. [00:04:00] It’s large proportions of them. So this was a key question. Um, during my PhD, I surveyed 14 sites every single month during spring and summer and a bit into autumn. In, uh, residential gardens and bushland remnants in Southwest WA, and I recorded every single plant that the bees visited, as well as the plants and their relative abundance in a hundred meter area.

And I looked at how, um, both the plant composition. And the plants that the bees visited, how that influenced bee abundance and diversity. And I found, shockingly, the higher diversity of plants there was, the fewer native bees there were. And this is, Like, absolutely opposite to some studies in the Northern Hemisphere, and the reason why is that when you’ve got a given amount of area, the higher number of plants you have, the lower [00:05:00] proportion of flowers there are of any particular plant species.

And if that’s a plant species that the bees really like, that’s going to be a small proportion of the overall foraging resources. And in residential gardens. a lot of plants are exotic plant species. So when you’ve got lots and lots of different plants, usually there’s fewer native plants. And looking at what the native bees visit, they definitely preferred native plants, but it wasn’t just any native plants.

Cause I also found no association or even negative association between native plant diversity. Again, for that reason, you have to plant the ones that the native bees prefer and not all native plants are native bee visited or pollinated some are pollinated by flies or birds or butterflies. Um, so you really need to, I guess, understand.

The foraging ecology of the species that you’re trying to help. And when it comes to Australian bees, like a really [00:06:00] clear preference is for Myrtaceae, which it’s a very diverse group that includes things like the gum trees, the eucalyptus and related general, like Anguifora and Carimbia, you can have 30 species foraging on just one .

Or a few trees in a habitat of one particular species of these preferred ones, which is like a lot of bees going to just this Keystone plant. Also Fabaceae, again, this is a very dominant plant family in Australia. It includes native pea plants, um, also Acacias, but when you have Acacia, most of them only produce pollen.

So you also need to make sure that you’ve got nectar plants there. And yeah, literally Myrtaceae and Fabaceae, lots of native bees are specialized on them. Roses and geraniums and poppies and pansies and sunflowers, all those things that are your typical like cottage garden [00:07:00] flowers, you’re going to not have a lot of native bees in your garden, especially the specialized ones because they just can’t forage on those plants.

And the reason why native bees in Australia are so specialized is because Australia’s been isolated from the rest of the planet for. You know, hundreds of thousands of years. So our flora and fauna have co evolved in isolation, and we can see this with marsupials, you know, koalas. They are very unique to Australia.

They only eat gum tree leaves. If you put a koala in a forest overseas, it will die because even if though there’s heaps of leaves, um, in a pine tree forest or an oak forest or something like that, it simply cannot survive on those. And same with. The Australian native bees, but the native thing goes, I guess, from all over the world.

There’s going to be bees in a given region that specialize on the plants there. You’re going to have generalists as well. So, you know, [00:08:00] there’s also Australian native bees that will visit exotic plants. The Amegilla , which includes the blue banded bees, they will visit basil and salvia and borage and ginger and tomatoes.

Some megachili will visit, you know, the thyme and mint and, you know, weedy species. Same with the Austroplebeia cassiae . Austroplebeia cassiae is a genus that’s found many places. Same with megachili. But when you’re looking at Australian bees that are unique to Australia, like Euryglosinae, which is a whole subfamily, the Trichocoletes, both of these groups, they specialize on the Mataceae and the Fabaceae.

So it’s really important to have those. And you know, they’re very common in the Australian landscape. So it makes sense that these bees specialized on these things that are very abundant. The plants you mentioned, are they nutritious for generalist bees too? Not just the bees that they are [00:09:00] specialized on?

Uh, yeah, so especially with the Myrtaceae, Myrtaceae visited by so many different things. Honeybees love them. They’re the main source of honey, Jarrah honey, red gum honey, yellow box honey, all the honeys that Australia is really well known from. Also Manuka, that’s also Myrtaceae. In Australia, we’ve got Over 60 species of Leptospermum, which is the genus that Manuka is from.

Manuka is from New Zealand, but we’ve got closely related species here. Sometimes it’s called Jellybush or Tea Tree. Um, they’ve got very accessible flowers. They flower prolifically. They produce a lot of pollen and nectar. The Fabaceae, not as many, but like, I know that the Megachile, which can be quite generalist, they will go for the Fabaceae.

So, um, this is a pattern that’s quite typical across pollination networks worldwide, is that they’re nested, [00:10:00] which means that if you’ve got a specialist bee, very rare will it have a one to one relationship with Um, a flower species or a flower genus, usually you’ve got a specialist bee that visits a flower that’s got a generalist pollination syndrome.

So lots of things can visit the flower, but the bee can only visit that flower lineage. And conversely, if you’ve got specialized flowers, specialized flower morphology, usually Their pollinators can visit other things because this makes the networks more stable. Um, cause you can imagine if, for example, the bees don’t emerge one year, then that flower species would also go extinct.

And you know, there are some, some quite tight relationships like that, but generally evolution has favored the sort of nested network where the plant species are quite nutritious for specialist bees and generalist bees. Are you seeing a mismatch in [00:11:00] bee emergence times and available floral resources due to climate change?

I published a chapter in a book on the impact of climate change on pollinators, particularly bees. And what we’re finding is that plants and bees are starting to shift their phenologies earlier, but plants are shifting them to a greater rate than bees. So bees are starting to emerge when the flowers are not.

Like at their peak and they’re starting to decline. Um, so we are seeing this and there can be like extinctions or disruptions of pollination networks. So we are seeing the effects of climate change on plant pollinator interactions and networks, which is, um, a big concern. And so we really need to make sure that we tackle climate change, as well as make sure that we have as many floral resources available in the landscape.

for bees so that, you know, they have some options, um, when they emerge. [00:12:00] Staying on that topic, can you recommend some plants that flower early and some that will be around into the autumn? So it’s going to vary so much depending on where you are in Australia. Some plants will bloom for like a long time, otherwise others a period of just a few weeks.

I find the Melaleuca, they are really attractive for bees, but they have very short flowering periods. Um, some of them, and then you’ve got like longer flowering species that are sort of the herby, perennial herby things like Plectranthus is very good for many bees, but yeah, it’s going to vary, I guess, depending on.

Where you are and what particular plant species, the carimbia caliphila, which is the marri tree. That is a key resource for native bees and it flowers sort of January to March and [00:13:00] by March in Western Australia, which is where marri is endemic. There’s not much else flowering and so it is a keystone resource.

there at the beginning of the season. That’s when lots of native peas are flowering. So they’re really good. Yeah. Generally like having the Myrtaceae and Fabaceae flowering as well as some perennials and maybe some annuals, um, is a good idea. I’ve got a book called creating a haven for native bees, and it’s got a big list of many plants that I know are really attractive to native bees.

So if you select. You know, quite a few of those and make sure you’ve got more than just like one plant of them, like a couple plants of each, then you can have that sort of, um, phenology covered. Planting in winter, depending on where you are, you know, it’s great to have something still flowering to supply birds and flies.

[00:14:00] In the more southerly parts of Australia, the native bees aren’t going to be active then. So really focus on the spring and summer flowering species. Why bees? Why do you do what you do? Uh, I really love bees so much. They’re just like a huge part of my life. I think about them literally every day. I have them tattooed on my body.

Yeah. They just become part of my persona. Yeah, I didn’t love bees. Like, I always loved bees, but they weren’t like, yes, I guess something that I thought about all the time, mainly because I didn’t realize there were that many bees. I thought there were honeybees and bumblebees and that’s all really, which is yeah, really sad and shocking.

And I really hoping to educate community, especially children about the diversity of bees and how amazing they are. because I think it’s really sad that lots of people grow up just knowing that there’s [00:15:00] honeybees and that there’s not an incredible diversity of native bees that have all these different ecologies and behaviors and lifestyles and appearances.

It’s a beautiful representation of biodiversity and diversity, and that’s what I love about them. And you’re always learning something, something new. Um, they’re also really cute and beautiful. A great environment to study them in because I love nature. And so getting to go out in nature is, is fascinating.

Also have like, I love detail. So I love being able to like, look at them under the microscope and figure out their features and what species they are. And yeah, they, they obviously a big part of nature in the ecosystem and yeah, as a huge nature animal wildlife lover, they’re, you know, I guess the perfect group to study when you’re such a nature nerd.

In an isolated and protected environment like Australia, the effects of climate change are so much more pronounced. [00:16:00] It’s on us to supply the floral resources bees and other pollinators need to fight back against the loss of their food and their land and the drastic weather changes that threaten their existence.

 Be sure to visit thebeesknees.website to learn more about Kit and her important work. Thanks so much for listening today. I’m grateful for your interest. Until next time, keep blooming!