Treesearch

Context: Habitat loss and fragmentation are the most pressing threats to biodiversity, yet assessing their impacts across broad landscapes is challenging. Information on habitat suitability is sometimes available in the form of a resource selection function model developed from a different geographical area, but its applicability is unknown until tested. Objectives: We used the Mexican spotted owl as a case study to demonstrate how models developed from different geographic areas affect our predictions for habitat suitability, landscape resistance, and connectivity. We identified the most...

A landscape succession paradigm has shaped much of our understanding about the processes of forest emergence and transformation in the United States. Drawing heavily from theory and method in environmental history, this paradigm has focused attention on the role of landscape-scale shifts in land use and land cover in the production of forests. The geography of cities is patchy, dynamic and heterogeneous, with change and differences occurring at much smaller scales (e.g. Jacobs 1961; Clay 1973) compared to coarse scale of stand replacing successions affecting rural forests (Grove et al....

Background: Historical forests (circa 1799 to 1846) of Indiana were predominantly composed of American beech (25% of all trees) and upland oaks (27% of all trees). I compared historical forest composition, using studies of smaller areas to approximate composition for uncommon species or genera (< 4.5% of all trees) and forest types, to current forest composition and forest types in Indiana. I also compiled published historical density estimates from small studies and estimated current density for the state. Results: Current forests are diverse with an even composition of many eastern...

Occupancy-based surveys are increasingly used to monitor wildlife populations because they can be more cost-effective than abundance surveys and because they may track multiple species, simultaneously. The design of these multi-species occupancy surveys affects statistical power to detect trends in occupancy because individual species vary in resource selection, detection probability, and rarity. We tested for differences in the ability of a large-scale monitoring program to detect changes in single-species occupancy of 13 medium–large mammal species captured on n = 183 cameras systematical...

The success of tree colonization by bark beetles depends on their ability to overcome host tree defenses, including resin exudation and toxic chemicals, which deter bark beetle colonization. Resin defenses during insect outbreaks are challenging to study in situ, as outbreaks are stochastic events that progress quickly and thus preclude the establishment of baseline observations of non-infested controls. We use synthetic aggregation pheromones to demonstrate that confined Ips bark beetle herbivory can be successfully initiated to provide opportunities for studying interactions between bark...

Sirex noctilio is an invasive woodwasp that, along with its symbiotic fungus, has killed pine trees (Pinus spp.) in North America and in numerous countries in the Southern Hemisphere. We tested a biological control agent in North America that has successfully controlled S. noctilio in Oceania, South Africa, and South America. Deladenus siricidicola nematodes feed on the symbiotic white rot fungus Amylostereum areolatum and can switch to being parasitic on S. noctilio. When parasitic, the Kamona nematode strain can sterilise the eggs of S. noctilio females. However, in North America, a...

Lower-tropospheric wind maxima, known as low-level jets (LLJs), play a vital role in weather and climate around the world. In this study, two 10-year (2006–2015) regional climate simulations using current (2011) and future (2100) land-use/land-cover (LULC) patterns over the continental United States (CONUS) are used to assess the sensitivity of LLJ properties, including jet occurrence, maximum speed, and the elevation of the maximum, to changes in LULC. The three simulated LLJ properties exhibit greater sensitivity in summer than in winter. Summertime jets are projected to increase in...

Forests across the globe are faced with a rapidly changing climate and an enhanced understanding of how these changing conditions may impact these vital resources is needed. Our approach is to use DISTRIB-II, an updated version of the Random Forest DISTRIB model, to model 125 tree species individually from the eastern United States to quantify potential current and future habitat responses under two Representative Concentration Pathways (RCP 8.5 -high emissions which is our current trajectory and RCP 4.5 -lower emissions by implementing energy conservation) and three climate models....

Forests have become increasingly fragmented throughout the US, with residential development serving as the primary driver of these changes. These altered landscapes have provided suitable conditions for a broad range of wildlife, including blacklegged ticks and their hosts. Lawns dominate residential landscapes, and thus their management has the potential to reduce the likelihood of contact with ticks in residential yards. We tested the hypothesis that lawn mowing frequency influences tick occurrence in 16 suburban yards in Springfield, MA. We conducted 144 tick drags in lawns of various...

The success or failure of fish populations in rivers is intimately linked to a complex and interconnected series of ecological interactions. This complexity can make it difficult to predict how organisms within river ecosystems will respond to management actions and other environmental changes. To aid in solving this dilemma, we constructed a food web simulation model termed the Aquatic Trophic Productivity (ATP) model. The ATP model mechanistically links the success of fish populations to the dynamics of river food webs and the abiotic conditions that influence these webs. This report...