Conservation Conversation with Mike Harrison, Natural Area Technician City of Calgary Parks, 16 February 2006 Visited Mike Harrison at Mayland Heights office during Teachers’ Convention in February 2006. Mike’s a Natural Areas Technician with The City of Calgary, and an expert on birds and wildlife and wildlands in Alberta. Mike accessed the City’s extensive database of maps, and sent me the digital aerial survey photograph of Whispering Woods taken in the fall of 2003. He also sent me the corresponding map layers which include contours, elevations, and street trees. As well, Mike provided me with a map of Nose Hill and adjacent communities, with layers indicating the habitats. He also sent me scales for each map, and habitat legends. During our meeting, Mike talked extensively about the smooth brome problem in many of Calgary’s natural areas. The brome originally came from Eurasia and was planted for forage and erosion control, and those uses continue. Smooth brome may be allelopathic in that it produces chemicals or toxins which damage other plants, e.g. fescue and rose, by inhibiting their root and plant growth. It’s aggressive, so it out competes native plants and creates its own monoculture. Kentucky bluegrass is not allelopathic, thus is not as invasive as smooth brome, even though it is also an introduced grass. It’s hard to study whether a plant is producing toxins, as it’s very complex. Still don’t understand why smooth brome is so aggressive. May not have the fungi and nematodes from its native soil to provide the checks and balances present in its natural environment. Fescue isn’t weak, but brome has advantages. Thus brome is a management problem. Current brome management practices: 1. Chemical a) Herbicide, but a problem if non selective ones also harm other organisms; b) Biocide, none at present for smooth brome [there are insect controls for some other invasive plants]. 2. Mechanical Ripping up and tilling. This has been done at an experimental restoration site on Nose Hill to the south of the gravel pit. An isolated area of brome and thistle surrounded by natives in a previously disturbed area [agriculture]. Four years ago brought in a farmer with his tractor to till area of the brome plus a bit further out from that. Did this 3x/year for 3 years to break rhizomes and release seeds. This was meant to exhaust the brome and thistle. Then seeded with native grasses, and no herbicide treatment. 3. Reverse fertilization Limiting the fertility of the soil favors natives. Brome likes nitrogen, so can put in carbon-rich mulches like sawdust, hay or even sugar. Could mulch the aspen understory to smother brome. In Nose Hill restoration, left some small aspen stands, as public perception of trees is very favorable towards all trees. But must realize we no longer have the browsers which would be nibbling the aspens and shrubs in favor of the grassland. Nose Hill restoration now at management stage. Monitoring and spot spraying thistle, and wicking herbicide directly on to brome tips when they are taller than rest of prairie plants. Will also try other things. Spring fires not helpful management for brome, as brome sprouts sooner and more quickly than fescue in the spring, especially in ravines where there is more moisture. Lack of controlled burns can also create a safety hazard as there can be a bigger thatch, so occasional fires would be more intense, spread more, and be more destructive. There can be a 0.5m height differential between brome and the natives. Nisku Prairie near Edmonton is managing brome with paint rollers soaked with Round Up, a non selective herbicide. This initiative is with volunteers, and supported by the Alberta Native Plant Council. People are leery of Round Up because it is a chemical being released into the environment. It targets chlorophyll, and becomes inert within the soil. There is a cost to this, and there is liability in Calgary regarding volunteers using this technique. Nose Hill will never again be as pristine, or as dynamic or diverse as it once was, but the restored and original parts will still attract native birds. We need biodiversity to support the whole ecosystem. There is much more there than just the grasses, e.g. native birds, voles, insects. Would lose forbs [flowering annuals and perennials] if became a brome monoculture. Would have a loss of species, with local extinctions and loss of habitat, then it would be gone. Sharp-tailed grouse have already disappeared from Nose Hill. The park has become isolated, an island due to fragmentation and human disturbance such as dog-walking. The badger is also threatened there. Deer don’t graze on brome. They browse on twigs. Cows love brome. Rabbits aren’t big enough to make a dent in the brome. Have lost bison, grouse, grizzlies, wolves, various butterflies. There can be a cascading effect with continued losses. Rough fescue is the dominant native grass. Native birds like Baird’s sparrow nest in native grasses, but not in brome. Grasslands important in carbon-cycling, and actually use more carbon than trees. There is more ‘bang for the buck’ per acreage with grasslands for carbon-cycling. Native grass root structures are deeper than non natives, and deeper than trees. Thus erosion of non native areas more drastic than erosion of native areas e.g. lost more riverbanks in June 2005 flooding in disturbed areas with non natives. The ‘texture’ on aerial photos of non native areas is lighter, and these are like ‘dead zones’ for native species.