Sunday, July 30, 2017

How the McMaster Prairie Project is Influencing Bee Biodiversity

Another great piece by our summer intern, Saige Patti!

Native bumble bees pollinate using a unique method called "buzz pollination."

For fifty years, a 149 acre McMaster property sat on Lions Club road with a faded fence and invasive buckthorn so thick that you couldn’t see through it. Now, it’s flourishing with biodiversity.

The change began 2014, when the McMaster Biology department removed the buckthorn, conducted a controlled burn, and reseeded the property with 40 native species to create a tallgrass prairie. This is a type of Carolinian habitat with a stable community of grasses and wildflowers such as blazing star and bergamot. Carolinian prairies support a wide variety of wildlife, including bobolinks, deer, voles, and butterflies.

Sebastian Irazuzta is a 3rd year PhD student at McMaster looking at how bees recolonize native habitats. He is comparing changing bee populations between the McMaster prairie and a similar remnant prairie habitat, located on Hamilton Conservation Authority property on Jerseyville Road. Irazuzta says that most research that has been done on this topic has been done in a controlled laboratory setting with fewer species.

After surveying the McMaster property from 2014 to 2016, they’ve found close to 180 species of bees. “For all of Ontario we know that there are around 410 species. For this area on the Niagara escarpment, the only other sizeable research that has been done has been around Brock University… they found around 132 species.” Irazuzta tells us.

Bee specimens from Irazuzta's collection show that native bees vary a lot in size.
There is great value in biodiverse bee populations. This is because different bees have different strategies for collecting pollen. While some bees stick pollen to their abdomen, others stick it to the hairs on their legs. Some even eat the pollen and regurgitate it later. When a flower receives visits from different types of bees, they access pollen from different areas of the flower.

Laboratory research has shown that enhanced seed production is not only determined by frequency of visits, but by diversity of pollinators.

Certain pollinators are most efficient at pollinating certain flowers, because they use unique methods. For example, bumblebees use ‘buzz pollination’. They vibrate the flower so that pollen comes off more easily and sticks to the bee. High bee diversity means plants produce more high-quality seeds. This is important for crops since more seeds means more food production.
Bees are important to us, but loss of prairies is making it harder for bees to find a food source.
Our native bees have ancient relationships with Carolinian wildflowers. They contain nectar that our native bees have relied on for centuries.

Prairie habitats once covered 14% of Ontario, but they were the first habitat to be destroyed when settlers arrived. Grasses were easier to remove than forests, so prairies were set on fire to make way for crops. Tallgrass prairies quickly disappeared. “Now we’re down to less than 3% prairie habitat, but that number is actually deceiving” Irazuzta says. Most of the habitat is left in very small sections, often on road sides or railway side. “Once you drop below a critical size, it can’t sustain lot of species. Fragmentation is a huge issue for all types of habitats, but it really does affect prairies.”  These fragmented prairies lead to extirpation of species they once supported.

How Prairie Habitats Are Restored

One way prairies are restored is with controlled burns. Most prairie species are adapted to fire, and many seeds even do better after a burn. When the ground is blackened and the soil gets hotter and drier, non-natives suffer; making more room for prairie species. The burns also get rid of pests, detritus, fungus, and insects that might harm the plants. Controlled burns can be used to kill non-native grasses before native plants have come up.

A traditional prairie habitat would have sandy soil, while the McMaster property is mostly clay. Irazuzta says that “Whenever we’re talking about doing restorations, people talk about re-creating a habitat that looks like a pre-existing habitat. But it’s never going to be exactly the same.” He says that the clay can still sustain a wide range of prairie species. “We just want to create an intact ecosystem that’s cycling energy through it quite well, so that it can sustain a lot of diversity”. The goal of the prairie is to have a really high diversity of plant material to encourage the widest range of insect pollinators.

Focusing on increasing biodiversity can help create stable habitats that can withstand the ever increasing changes in climate.

Creating sustainable Habitats in a Changing Climate

Ontario has been dried by drought last year and flooded by rain this year. The ups and downs of extreme weather conditions tend to extirpate species that are rare or exist in small populations.

Healthy, biodiverse habitats help keep more species around. Different types of natural lands surround the McMaster Prairie; there is old growth forest, Old Field (a term for an abandoned farm), wet meadow, and floodplains. All of these habitats are complimentary, and are also important for bees, which need nesting habitat to survive. Irazuzta says this habitat diversity “increases the mosaic of the landscape by providing different habitats that are closely linked to each other.”

Gardening in the City.

The importance of urban habitat is too often forgotten. “We need to stop thinking of nature as separate from us and realize that that it’s all around us,” Irazuzta says. “It’s in our own backyards.”

The unfortunate reality is that most land is not under conservation. To have a healthy environment we need a flourishing urban ecosystem.

When it comes to planting habitat in the local neighbourhoods, gardeners would do well to remember that pollinator friendly gardens are not only about the food source. When people cut and throw away dried stems before late spring, they are often throwing away the next generation of bees, who make nests in hollow grasses and stems. Bees need time to hatch before these grasses are cut.

Other bees make nests in bare soil, and mulch interferes with their access to soil. Having small hills of soil with slopes facing south can create nesting habitat for bees and other insects, as well as add an interesting landscape factor to your garden.

Irazuzta credits the Pollinators Paradise Project for working in areas that need habitat the most. In industrial areas that lack tree cover, creating pollinator gardens and a livable landscape is incredibly important to the urban ecosystem – supporting diverse life in and around our city.