The presence of landscape disturbances increases the establishment of exotic plants inside natural areas. Here, we examine the effect of human disturbances to prairie landscapes on the distribution and abundance of Kentucky bluegrass and smooth brome, exotic grasses that threaten the integrity of prairie ecosystems throughout the northern Great Plains. Using plant inventory data from Riding Mountain National Park in Manitoba, Canada, we investigated how roads, trails, and the intensity of historic livestock grazing affect the distribution and abundance of exotic grasses. On the basis of our results, both Kentucky bluegrass and smooth brome were more abundant in areas closer to roads. Kentucky bluegrass was also more abundant in areas farther from trails and those historically grazed by cattle. Our research demonstrates that the effect of landscape disturbances on exotic grasses varies between species and suggests that patterns of invasion may reflect different introduction histories. Given our findings, conserving the integrity of northern fescue prairies should account for human disturbances of landscapes and their effects on the proliferation of exotic plants into areas of native prairie.

Natural forests are composed of a heterogeneous mixture of plant architectures that change temporally and spatially. In addition, variation in ridges, tree falls, natural clearing, logs and animal or man-made paths results in a topographic complexity which is likely to have a profound effect on the movements of animals within the forest.

High in the mountains between Norway and Sweden, archaeological survey has brought to light a trail marked by standing stones at regular intervals and tall enough to show above the winter snows. In the absence of any cultural material, the erection of the stones was dated by the diameter of the lichen spreads upon them, and corroborated by a study of the documents and radiocarbon dates. The authors argue that this was not an indigenous trail but one constructed by a Norse chieftain probably around the ninth century AD to gain safe access to the fur-trading Sami.

Although trails are widely recognized as an important element in the shaping of social and economic space, poor preservation and complex interpretations have meant that they are rarely the subject of systematic archaeological analysis. Ancestral Pueblo trails of New Mexico's Pajarito Plateau, in contrast, are both well-preserved and easily identified, providing an opportunity to study patterns of movement through the landscape during the 500 years prior to Spanish colonization. This study discusses the broader issues of analysing archaeological trails with specific reference to the Pajarito case.