Thursday, December 24, 2009
Sunday, December 13, 2009
When I checked the Environment Canada Weatheroffice website this morning, my clean, sharp -40 was perfectly bracketed by the -35 C at the City Centre Airport and the -45 C at the International Airport. Ten degrees Celsius seems like a startling difference for two airports so close together. The City Centre is a bit further north (53 34.2 vs 53 19.2 N), but ~50 m lower in elevation (671 vs 723 m). All else being equal, a site 50 m lower would be expected to average about 0.34 degrees warmer. The annual mean daily temperature of the City Centre (3.9 +/- 1.1), however, averages a full degree and a half Celsius higher than the International Airport (2.4 +/- 1.2).
This does seem strange for two weather stations only 30 km apart, and given the recent Climategate leak, perhaps a little paranoia is in order. The City Centre has been consistently claiming higher highs and higher lows than I can find on my thermometer (at almost the same elevation, 669 m, and only 15 km south). Could they be fudging the data to make things look warmer? I doubt it – as far as I can make out from the CRUtape Letters, all the value adding to the temperature data happens later, once the ‘scientists’ discover that the data does not agree with their models, and therefore, must be wrong.
Moreover, a simpler and well supported alternative answer is available – the Urban Heat Island Effect (UHI) - all the buildings and tarmac that absorb heat during the day and radiate it out at night and all the energy burned to keep the city going add up to a warmer local climate. So while the City Centre is usually warmer at night than my backyard, the backyard is often warmer than the International Airport. For morning lows, I’m often halfway in between – not surprising since the HBG is situated halfway in between the two airports and is in an area that is maybe half as urbanized as the City Centre. Daytime highs are more variable, but are more like the Airport than like downtown. UHI seems like a good explanation for these differences – and I would imagine that the International Airport is warmer than the rural areas around it.
My friend at Gardening Zone 3b near the City Centre seems to have an unfair share of UHI, but he displays the results beautifully on his blog, so I forgive him his 2-3 week advantage in spring bloom time and his later killing frosts (I’m a noble guy). I certainly don’t want my neighbourhood to get more urbanized, so I guess the HBG will just have to make do with the little UHI it has. The last couple of years, however, seem to be getting colder. That is a worry, as is the apparent correlation between sunspot activity and warmth (the Sun appears to be in a deep funk). If, as it seems, global warming was at best a delusion, then Zone 3 gardeners are going to miss it more than most people, except for Phil Jones and his mates, of course.
Saturday, October 31, 2009
Or are they? Well, the truth be told, we don’t really know because with few exceptions we have pretty much put all of our bees in one basket. However, the time may be coming when the other 99% of pollinators – e.g. the for-get-me-not frequenting flower fly below– receive their due attention.
Flower flies (aka hoverflies, Syrphidae) were one of the pollinator groups that were well represented in presentations last week at the Joint Annual Meeting of the Entomological Society of Canada and the Entomological Society of Manitoba in Winnipeg. Usually I would consider attending such a meeting additional work, but this time it was vacation – perhaps the reason I had an unusually good time for a bug meeting. Not that sitting on one’s butt from 8 am until 5 pm listening to bug talks, not even with the aid of fly papers, is all that easy, but the friends, fine food, and Forks all made for a pleasant time. ‘Winterpeg’ was anything but wintry, the simple monument at Louis Riel’s grave among the Dutch doomed elms in the Saint Boniface churchyard strangely moving, and the bug science less debased by climate change hyperbole than has become usual. However, it was the plethora of papers on pollinators that made the meeting for me.
Anyone who answered the question in the picture above with the Laphria on the left (a robberfly, Asilidae) must have missed the doubly unfortunate damselfly and mites.
Monday, October 12, 2009
Edmonton City Centre Airport and their Climate Data Online button. It is a bit complicated and unintuitive, but eventually I was able to find the monthly reports that included maximum and minimum temperatures for downtown Edmonton going back to 1937 (Edmonton City Centre AWOS [2009-2005], A (2005-1937]). You have to go back 50 years, to 1959, to find another stretch of 5 days with below zero maximum temperatures in the first half of October (and then again in 1957) – so very unusual, but not unprecedented. Below freezing daily highs are more common in the second half of October (e.g. in 2004 – the year of the 5 cm snowfall on September 9), but above freezing and even relatively warm temperatures are more the norm.
The City Centre Airport shows a distinct Urban Heat Island Effect (UHI) compared to my backyard records and is usually another several degrees warmer at night than the International Airport (records to 1961) in the countryside south of town. However, a long stretch of subzero days in the first half of October is unprecedented in the last 48 years at the International Airport (which opened in 1960 - presumably the fields where the airport would be in 1959 would have had the same cold stretch as Downtown in 1959). So, why all this harping on cold? Well, the ground is frozen and I’m still waiting for my Dutch Spring bulb order!
One could argue that a Home Bug Gardener would be better planting native, rather than exotic bulbs. After all aren’t native plants good and alien plants bad (or at least suspect)? Alas, the native-alien divide is one of those twilight zones where the science becomes gray and shadowed by politics and beliefs trump facts. My Australian instilled aversion to invaders is still trying to come to grips with Alberta’s recently deglaciated landscape awash with relatively recent invaders. But whichever side of the invasive species controversy I eventually come down on, science or xenophobia, I know that after the long nasty winters here, I need some cheerful flowers as early in the Spring as possible. So what does Alberta have to offer in the way of native bulbs?
To answer that question, of course, one has to first define ‘bulb’ (‘Alberta’ being well defined and ‘native’ seems okay when not scrutinized). Bulb does have a reasonably precise technical definition relating to food-filled underground shoots and leaves, but after the botany final exam is over, no one seems to adhere to the limited concept, but instead embraces any underground storage organ that looks bulbish to them. To avoid more confusion than is necessary, my definition of a bulb is anything listed in the bulb bible: “Bulbs” Revised Edition 2002 by John E. Bryan (Timber Press, Portland OR). So tubers, corms, rhizomes, and some fat roots qualify.
Much to my surprise, I find that I have planted 4 Albertan true bulbs (Allium cernuum, Allium schoenoprasum [chives], Lilium philadelphicum, Camassia quamash), one AB ‘bulb’ (Maianthemum canadense), and three ‘bulbs’ from nearby areas that might reasonably have been expected to eventually make it to Alberta on their own (Iris setosa, Iris versicolor, Liatris spicata). That’s the good news. The bad news is that none of these plants is so foolish as to produce flowers in the earliest spring! In fact the Liatris (aka Blazing Star or Gayfeather) is sitting frozen in mid-bloom at the moment. No, spring colour is up to the 60-odd accessions (i.e. named species, varieties, or cultivars) of exotic alien bulbs – the vast majority of which do their best to add some early spring colour to the HBG.
Yes, it is true, the Home Bug Gardener has planted almost 10 times as many species/varieties of alien bulbs as of North American natives. I’m a bad, bad, bad native gardener, or at least not much of a purist. And that’s okay with me, because after 8 months of winter, I need to see something attractive in the garden, even if it is an evil alien. Not that these plants are especially bug-friendly. It is true that the bees and flies that are around will visit many of them, but not with the same fervour that they go after later bloomers. The earliest HBG bloomer, the native coltsfoot (Petasites palmatus), really is a bee magnet. But then again, so are many of the exotics that put in an appearance later in the Spring. The bees and bugs may be particular about what they feed on, but I don’t think they have any bias about country of origin.
Sunday, October 4, 2009
The Far North Garden for my stringing consonants on my blog instead of spewing curses at the neighbours. Among the many well written and balanced postings available for whiling away a Sunday morning in a non-confrontational manner was a recent one on volunteer borage (Borago officinalis), one of my favourite alien plants. As a home bug gardener, I suppose I should claim that I plant borage for the bees, but really I like its “feed me” ‘Little Shop of Horror’ looks. Besides, I only planted it once five years ago and after that it has planted itself. Every year now I can enjoy its true blue flowers and spindly and spiny spread with no additional effort.
Actually, although the seed packet from the Devonian claimed our milkweed was the Butterflyweed Asclepias tuberosa, a beautiful and not very aggressive plant with flat heads of orange flowers that would be marginally hardy here (usually rated to Zone 4), what actually emerged from the ground was a much more vigorous monster. I believe this is Swamp or Rose Milkweed, Asclepias incarnata, which has ball-like umbels of pinkish lavender flowers and wandering roots that quickly took over our primary potager bed. Once its roots were contained in a smaller bed, however, it became a welcome addition to our garden.
Saturday, September 19, 2009
Sunday, September 6, 2009
Thus, overly aggressive hunting wasps would tend to come to a bad end, but those with a more philosophical attitude, can move on, start another nest, and send daughters and sons into the next generation. That doesn’t mean they won’t put up a bit of a fight, many are capable of delivering a painful sting, but in general they aren’t going to slug it out with something as large as a human. It also helps that solitary wasps are only really interested in hunting down spiders or insects to feed their grubs and an occasional sip of nectar at a flower to keep them going. When a solitary wasp finds you at a picnic, it is most likely because you have attracted flies (which many take as prey) or you have put your blanket over their nest in the ground and they can’t find their way home. Some solitary wasps are members of the Vespidae, the home of hornets and yellowjackets, or close relatives like the mostly black spider hunting wasps in the Pompilidae, but most belong to other families.