Are linear habitats in agrarian landscapes source areas of beneficial or pest rodents?

This study tested the hypotheses that populations of the montane vole Microtus montanus (a potential pest species) and deer mouse Peromyscus maniculatus (a potential beneficial species) in linear habitats will be (i) positively related to the type of vegetation (abundance and diversity of vascular plants) within and adjacent to those habitats; and (ii) correlated with population changes and productivity (reproductive performance, recruitment, and survival) in nearby apple (Malus domestica) orchards. Population dynamics of M. montanus and P. maniculatus were measured by intensive live-trapping from 2003 to 2006 in replicated hedgerows, riparian strips, and nearby orchards, in southern British Columbia, Canada. Hedgerows were borders between orchards, orchards and old fields, as well as orchards and natural forest. Contrary to hypothesis (i), M. montanus and P. maniculatus populations were not positively related to vegetation type within linear habitats and their adjacent crop and non-crop areas. Mean abundance and diversity of vegetation attributes were similar among linear habitats. Hypothesis (ii) was not supported for M. montanus populations in linear habitats since they did not correlate with population changes in nearby apple orchards, during a peak year in abundance. Populations of P. maniculatus were similar in abundance and other demographic variables among the linear habitats and apple orchards, and hence hypothesis (ii) was supported for this species.     

Optimal hardwood tree planting and forest reclamation policy on reclaimed surface mine lands in the Appalachian coal region

We study the optimal hardwood tree planting decision on reclaimed surface coal mines in the Appalachian region using a mine operator-focused, expected cost model that recognizes costs of preparing the site for tree planting, unit costs of planting seedlings, and opportunity costs of reforestation treatments and the performance bond. We also consider the possibility of failed initial attempts by incorporating the probability of reforestation success, based on empirical seedling ,survival rates and regulated tree survival standards, as well as fixed and unit costs of returning for additional planting. Optimal planting levels from 319 to 780 trees per acre and expected costs from $1049 to $2338 were found using simulations over a range of unit planting costs, fixed costs of replanting, tree survival standards, and interest rates. Further simulations compared optimal planting across un-weathered gray sandstone and weathered brown sandstone substrate materials, finding gray sandstone to be associated with lower expected costs. We conclude that optimal planting density and expected reforestation cost are sensitive to economic parameters, regulations, and planting substrate materials; and those policies influencing these factors may have substantial impact on reforestation outcomes and the choice of post-mining land use by mine operators. Our study provides a framework for understanding forest reclamation decisions that incorporates incentives faced by the mine operators who develop and implement the plans for mine reclamation, including forestry.