Monarchs make the news

Monarch Butterfly on Common Milkweed, photo by David Hobden

Pollinators are numerous and varied, but a segment that for the media comprises predominately butterflies or bees. Monarch Butterflies are well-known as the poster child for pollinators, only recently having to fight it out with the cute and furry Bumblebee for facetime on pollinator topics. However, the plight of the Monarchs remains: as a migratory species dependent upon very specific plants to complete its lifecycle, this is a very vulnerable butterfly to climate change and land conversion.

The Toronto Star published an article this weekend on the plight of the Monarchs, and made mention of some initiatives to encourage people to create pollinator gardens. Fletcher’s own Monarch Waystation Project (and waystations in general) wasn’t covered, but we’re always happy to see how important Monarchs are to people across Canada. Apparently, Monarchs made it to Calgary which is a first in recorded history! The biggest issue of Monarchs reaching even further destinations is that they cannot find sufficient food sources or larval host plants. This is a greater issue in the Prairies where grazing lands preclude introducing Common Milkweed nearby as it is poisonous to livestock. Thus, urban centres will become some of the most important habitat areas for migrating Monarchs. Continue reading

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Talking to your plants – do you listen to their answers?

Some plant enthusiasts believe that talking to their plants improves plant growth. Pity we can’t more easily discourse rather than talk at our green friends – but how do plants communicate with each other?

Daniel Chamovitz, director of the Manna Center for Plant Biosciences at Tel Aviv University, talks about his new book What a Plant Knows in this Scientific American podcast (about 30 minutes long).

Wasps in our shed and wasp-human interactions

 by Sandy Garland

Polistes dominula nest

This nest is about 10 cm in diameter and you can see sealed cells containing eggs as well as adult wasps tending larvae.

As always by this time of year, wasps have discovered what a nice warm place our shed is and what a great place to build a nest.

As usual, at least half a dozen open “umbrella” nests have been started by paper wasps (Polistes dominula). Nervous about these at first, we now ignore them and the wasps ignore us.

This year, a new kind of nest appeared for the first time – a small closed round hanging nest (see photo below). As the nests are peculiar to each species, we knew this was a different kind of wasp. Christine kindly identified them from photos as aerial yellowjackets (Dolichovespula arenaria).

I am very cautious around yellowjackets because I accidentally disturbed a ground nest once and was stung all over my hands before I realized what was happening and ran away. However the aerial species seems as docile as the Polistes wasps. 

Aerial yellowjacket nest

This little 7-cm-diameter “paper” ball is the first and only aerial wasp nest in our shed.

BUT, this differs for different people. I happened to meet two colleagues just leaving the FWG and stopped to chat. They came to look at the nests and the aerial yellowjackets immediately flew out of their nest and around in circles in a very agitated way. One of my friends also has this effect on bald-faced hornets (another kind of yellowjacket, which builds a much larger round paper nest on tree branches). In contrast, the other friend once spent many hours sitting directly under a bald-faced hornet nest studying their behaviour. During all that time, the wasps paid no attention to her. 

Wasps were a topic on the Naturelistserv this week too. One contributor mentioned how grateful they were for wasps when they used to milk cows out in the field: “That gave us lots of time to observe insects around the cow, and we really appreciated the work of the White-face Hornet. These  predators took flies right off the surface of the cow – or on the wing. Face flies, deer flies, stable flies, everything up to the size of the monster black horsefly. In that situation the hornets were very welcome companions.”

One last thing: as I was resizing these photos for uploading, I noticed that the Polistes wasps have different yellow markings on their faces (see photos below). I wonder what this means. A quick Google search turned up this National Geographic article – how interesting!

Polistes dominula faces

Breeding new hope: American Chestnuts in the Ontario Landscape

A trail leading into the Ash Woods at FWG. photo: C Hanrahan

Foresters, landscape architects and conservationists are familiar with the seemingly never-ending parade of native trees on the road to being endangered. In the 70s, Dutch Elm disease changed the Ontario landscape forever as native elms (Ulmus americana, in particular) died, leaving gaping holes in the urban forest and newly shade-less streets. Today, the same bleak outlook applies to ash trees, another long-time landscaping stalwart. The Emerald Ash Borer is the culprit here, whose larvae feed on the inner wood of ash trees creating extensive galleries, slowly killing the tree through an effective girdle as water and nutrients can no longer reach the leaves. Expensive inoculation programmes are the current solution. For example, selected trees on the Experimental Farm are being treated but not all – and protecting street trees around the city would be prohibitively expensive for the city alone to cover (though they are engaged in a programme of selective inoculation with TreeAzin, and encourage ash tree owners to do the same). At Fletcher, we can only wonder for how much longer our Ash Woods habitat area will retain that name. Continue reading

Mowing strips and garden beds

by Sandy Garland / FWG

Brick mowing stripRegular visitors to our Backyard Garden may be wondering what we are doing along the edge of some of the flower beds. Until recently, most beds were edged with a double row of bricks. This “mowing strip” allowed the lawn mower to run along with one wheel on the brick path and trim the grass right to the edge. Nice and easy for the volunteers who mow.

BUT, the volunteers who maintain these beds complained that it was very difficult to weed between the bricks – in fact impossible, and weeds kept growing back as fast as they were pulled out. Others added that the bricks did not create a very “natural” look in a wildlife garden.

dirt stripSo, out they came! To help the mowers, we are trying to replace the bricks with a packed strip of soil around each bed. Time will tell whether this solution works for everyone.

Growing Common Milkweed – Experimenting from seed and transplants

by Sandy Garland / FWG

As part of our Monarch Waystation project, we’re trying to learn everything we can about growing milkweeds, especially Common Milkweed. Common milkweed bloomingDespite the fact that it’s often viewed as a weed, it’s surprisingly hard to grow.

We prepared seeds of both Common and Swamp Milkweed by putting them in the refrigerator in damp vermiculite for a couple of months over the winter. We also scattered seeds outside – in a home garden and at the FWG.

But the germination rate for Common Milkweed has been only about 12-15% – much lower than for swamp milkweed (67%). As far as I can tell, none of the seeds sown outdoors has germinated.

Meanwhile, several people have also donated milkweed plants to the FWG, and we’ve had great success with those. Most of the ones we put in last fall survived the winter. See photos here.

Transplanted milkweedsAt the beginning of June, I planted 6 donated plants in a new area near Prince of Wales Drive. Although they were surrounded by dog-strangling vine, planted in the hardest, most inhospitable soil, and never watered, they are all still alive and thriving (see photo at right).

According to the experts, Common Milkweed likes to grow in disturbed areas. I think that means it’s easy to establish, but what are the implications for the long term? Do we have to dig up these areas every few years and replant?

One other experiment we are going to try is cutting some plants back (to about half their height) in the next week or so, now that they’ve finished blooming and again in early August. That will cause fresh growth and young leaves for caterpillars – especially those that will become the adults that will make the journey south to Mexico this fall. We want to them to be as strong and healthy as possible!

“Holes” in Dog-strangling Vine

by Sandy Garland / FWG

Several years ago, we noticed an odd phenomenon in the middle of a field that had pretty much been taken over by dog-strangling vine (DSV). A circle of mostly grass, about 4-5 feet in diameter had no DSV growing in it. I mentioned our “crop circle” to colleagues at the garden and one speculated that a walnut tree had been growing there and its roots were producing something that was inhibiting DSV.

This made sense, but then the circle grew and grew until this year, it’s a good 30 feet in diameter! If residual tree chemicals had created the circle, you would expect less effect as time went on. Nothing growing in the circle seemed to explain the lack of DSV – meadow foxtail grass and another common species, both of which grow abundantly at the FWG. Continue reading

Honeybees are on the rise but pollinator demand grows faster

Recent research shows that while populations of Honeybees are on the rise, the overall need for pollinators is rising faster. Good reasons to create pollinator habitat for our many native bees and pollinating insects near crops!

From Cell Press: The notion that a decline in pollinators may threaten the human food supply – producing a situation that has been referred to as a “pollination crisis” – can be considered a myth, at least where honey bees are concerned, say researchers reporting online on May 7th in Current Biology, a Cell Press publication. First of all, most agricultural crop production does not depend on pollinators. On top of that, while honey bees may be dwindling in some parts of the world, the number of domesticated bees world-wide is actually on the rise, their new report shows.

“The honey bee decline observed in the USA and in other European countries including Great Britain, which has been attributed in part to parasitic mites and more recently to colony collapse disorder, could be misguiding us to think that this is a global phenomenon,” said Marcelo Aizen of Universidad Nacional del Comahue in Argentina. “We found here that is not the case.”

By analyzing data from the Food and Agriculture Organization of the United Nations for temporal trends in the number of commercial bee hives, they found that the global stock of domesticated honey bees has increased by about 45 percent over the last five decades. That increase has primarily been driven by an increased demand for honey from a growing human population, rather than an increased need for pollinators, he added.

But the news isn’t all good: The data also show that the demand for crops that rely on insects for pollination has more than tripled over the last half century, suggesting that the global capacity for pollination may still be under considerable stress. These crops include “luxury” agriculture items, now common in any supermarket, like plums, raspberries, and cherries, as well as mangos, guavas, Brazil nuts, and cashew nuts.

“We were particularly astonished when we found that the fraction of agricultural production that depends on pollinators, which includes all of these luxury agriculture items, started growing at a faster pace since the fall of communism in the former USSR and Eastern Europe, and at a much higher rate than the larger fraction of agricultural production that does not depend on pollinators, including wheat and rice, which just follow human population growth,” Aizen said. “Although the primary cause of the accelerating increase of pollinator-dependent crops seems to be economic and political – not biological – their rapid expansion has the potential to trigger future pollination problems for both these crops and native species in neighboring areas.”

The associated increase in demand for agricultural land could also hasten the destruction of habitat that now supports hundreds or thousands of species of wild pollinators, which would in turn cause a drop in crop yield, he said.

“Most importantly, decreasing yield by these pollinator-dependent crops surely would imply rising market prices, which undoubtedly would constitute a further incentive for their cultivation,” Aizen said. “This situation would create a positive feedback circuit that could promote more habitat destruction and further deterioration of pollination services. The good news is that less-intensively managed agro-ecosystems that preserve patches of natural and semi-natural habitats and uncultivated field edges can sustain abundant and diverse communities of wild pollinators.”

 The researchers include Marcelo A. Aizen, Universidad Nacional del Comahue, Rio Negro, Argentina; and Lawrence D. Harder, of University of Calgary, Calgary, Alberta, Canada.

Contact: Cathleen Genova
cgenova@cell.com
617-397-2802
Cell Press

http://www.eurekalert.org/pub_releases/2009-05/cp-hba043009.php

Last Summer Sunday Work Bee Event! Come on Out and Bring your Friends!

by Barry Cottam │ Tuesday Invasive Species Group leader at FWG

2012 weekend weed bee half-day events –> Sundays: 8 & 15 July, 12 Aug, 9 Sep from 8:30AM until 12:30PM

Meet at the Interpretation Centre (Building 138); Find us with Google Maps

The Fletcher Wildlife Garden, our Hidden Gem, has been virtually taken over by Dog-strangling Vine (DSV). If you don’t know what it looks like, then you will see acres of lovely green here at the FWG. But if you can recognize DSV, you will immediately realize how much of a problem it has become. First noticed in 1991, around the time the FWG was started, DSV has spread until it is now out of control. Serious, long-term measures are required to put a dent in the population of this highly invasive plant.

Weed bee volunteers working in terrain the scythes can’t go.

Continue reading