Poecilus lucublandus (Coleoptera: Carabidae) and Pterostichus mutus Do Not Feed on Hair Fescue, Red Sorrel, and Poverty Oatgrass Seeds

Poecilus lucublandus (Say), Pterostichus mutus (Say), and Harpalus rufipes (De Geer) are abundant Carabidae in lowbush blueberry fields and may contribute to weed seed predation. We used laboratory no-choice test experiments to determine if these beetles feed on seeds of hair fescue (Festuca filiformis Pourr., Poales: Poaceae), poverty oatgrass (Danthonia spicata L.), and red sorrel (Rumex acetosella L., Caryophyllales: Polygonaceae), which are common weeds in lowbush blueberry (Vaccinium angustifolium Ait., Ericales: Ericaceae) fields. Poecilus lucublandus and P. mutus did not feed on seeds of the test weed species, but H. rufipes consumed on average over 30 seeds of each species. There are other weed seeds in blueberry fields that could be palatable to P. lucublandus and P. mutus, which warrants further research on the granivory potential of these important carabid species.

Additions and Range Extensions to the Vascular Plant Flora of the Continental Northwest Territories and Nunavut, Canada, II

Based on field reconnaissance since the publication of Flora of the Continental Northwest Territories in 1980, particularly in the District of Keewatin and northeastern District of Mackenzie (Nunavut) and Nahanni National Park, information is provided on geographically significant plant occurrences. One new taxon, Polemonium boreale forma albiflorum, is described, fourteen native taxa are reported as new to the region: Carex hoodii, C. microptera, C. petasata, Corispermum hookeri, C. ochotense, Danthonia spicata, Draba stenoloba, Erysisnum coarctatum, Halenia deflexa, Polygonum fowleri, P. ramosissimum, Salix rotundifolia ssp. rotundifolia, Silene uralensis ssp. ogilviensis, and Vaccinium ovalifolium. Five introduced taxa, Crepis tectorum, Corispermum villosum, Deschampsia elongata, D. incisa var. incisa, and Medicago sativa ssp. falcata are new to the flora of the region. Two native taxa, Danthonia intermedia and Potentilla porsildiorum are deleted from the flora and Ranunculus aquatilis var hispidulus is placed in synonymy. Significant range extensions for 125 native and one introduced taxon are included.

THE BIOLOGY OF CANADIAN WEEDS.: 92. Danthonia spicata (L.) BEAUV. IN ROEM. & SCHULT.

Danthonia spicata, poverty-oat grass, is a native North American perennial grass of pioneer habitats. It invades agricultural lands in eastern Canada with dry soil and low fertility. Unpalatable to livestock, it is an increaser species in heavily grazed or nutrient depleted pasture. A polymorphic reproductive system incorporates chasmogamy, cleistogamy and heteromorphic diaspores (dispersal unit). Clavicipitaceous fungal parasites are often present and affect productivity, reproduction, competitive fitness and possibly predation of their hosts.Key words: Danthonia spicata, Poverty oat grass, weed biology

Rapid genotypic change in a population of the grass Danthonia spicata following disturbance

A population of the grass Danthonia spicata growing in a pine–hardwood forest in northern lower Michigan was studied before, during, and after a period of major disturbance. Samples of the aboveground population were collected after clear-cutting but before fire, 9 days after fire, 10 months after fire, and 13 months after fire. Change was examined by growing clonally replicated genets in a series of light and watering treatments in the greenhouse. There was a significant change in the composition of the population after fire. Genets collected following the fire grew faster and larger in the 100% light treatment than individuals collected before the fire. Differences among collections were small or not significant for plants grown in the 20 and 6% light treatments. The watering treatments showed little or no effects. Although there are limitations in the interpretation of common garden studies, the differences among collections appear to have a genetic basis. The growth characteristics of genets collected after the fire showed possible adaptation to postfire conditions. These results suggest a greater importance for genetic adaptation in the persistence of D. spicata during secondary succession than had been concluded from earlier experiments.