Life Sciences Commons^™

Development Of A New Habitat Mimicking Tool For Assessing Larval Salamanders In Temperate Forest Streams, Margaret E. Maloney, Eric B. Borth, Chris Skalski, Ryan W. Mcewan

Biology Faculty Publications

Small streams are a high priority for conservation and an important target for biomonitoring. Stream salamanders are a useful indicator for biotic integrity of headwater streams; however, assessing stream salamanders is a challenging endeavor and existing methods can cause habitat disturbance or require expensive equipment. Our goal was to develop an artificial habitat that mimics the natural habitat that salamanders prefer, leading to rapid colonization and that also (1) represents a standardized area and (2) is easy to handle for rapid assessment. After developing a new artificial habitat (the Maloney Salamander Hotel), we tested the device in a variety of …

Lethal Effects Of Leaf Leachate From The Non-Native Invasive Shrub Amur Honeysuckle (Lonicera Maackii) On A Model Aquatic Organism (Hyalella Azteca), Eric B. Borth, Kevin W. Custer, Ryan W. Mcewan

Biology Faculty Publications

The invasive shrub Lonicera maackii (Amur honeysuckle) is a problematic species in the eastern United States and there is growing evidence that materials from this species have toxic effects on some organisms. We used a sequence of microcosm bioassays to assess the influence of L. maackii leaf leachate on the macroinvertebrate Hyalella azteca, which is a standard aquatic organism for toxicity assessment. In a laboratory setting, H. azteca were exposed to a leaf leachate dilution series (6.25%, 12.5%, 25%, 50%, 100%) in 48-h toxicity tests. This was repeated throughout the growing season to assess the potential for changes in …

The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan

Biology Faculty Publications

Identifying the drivers of community assembly has long been a central goal in ecology, and the development of functional diversity indices has provided a new way of detecting the influence of environmental gradients on biotic communities. For an old-growth Appalachian forest, we used path analysis to understand how patterns of tree functional diversity relate to topography and soil gradients and to determine whether topographic effects are mediated through soil chemistry. All of our path models supported the idea of environmental filtering: stressful areas (high elevation, low soil moisture, low soil nutrients) were occupied by communities of low functional diversity, which …

Lethal And Sublethal Effects Of Novel Terrestrial Subsidies From An Invasive Shrub (Lonicera Maackii) On Stream Macroinvertebrates, Ryan W. Mcewan, Kevin W. Custer, Eric B. Borth, Sean D. Mahoney

Biology Faculty Publications

The biology of headwater streams is intimately linked to that of the surrounding terrestrial environment through organic matter subsidies. Lonicera maackii, an invasive shrub that is becoming abundant in headwater stream riparian areas, deposits substantial quantities of organic matter into the aquatic system. This organic material has allelopathic effects on terrestrial plants and insects, and a growing body of work suggests strong connections between L. maackii invasion and aquatic biota. Lonicera maackii deposits fruit and flowers in quantities and timings that are unique, and we tested the hypothesis that these subsidies would negatively affect survival and growth of laboratory-cultured …

Tropical Cyclones Disrupt The Relationship Between Tree Height And Species Diversity: Comment, Teng-Chiu Lin, Lixin Wang, Chengyang Zheng, Ryan W. Mcewan, Chung-Te Chang, Jyh-Min Chiang, Chung-Hao Chi

Biology Faculty Publications

In a recent report on the patterns of tree species richness in eastern and western North America, Marks et al. (2016) claimed to have identified an operational indicator of environmental harshness (maximum tree height) and concluded that environmental stressors that limit tree height also act as ecological filters on species richness. Marks et al. (2017) attributed the positive association between species richness and maximum tree height to both the direct effects of environmental harshness on species richness and the indirect effects of environmental harshness on species richness as mediated by maximum tree height.

This finding overlooked the fact that many …

A Review On The Invasion Ecology Of Amur Honeysuckle (Lonicera Maackii, Caprifoliaceae), A Case Study Of Ecological Impacts At Multiple Scales, Rachel E. Mcneish, Ryan W. Mcewan

Biology Faculty Publications

Invasive species are of global importance because of their impacts on ecological communities, habitat structure, native community dynamics, and ecosystem processes and function. Scientists and conservation managers are increasingly focusing on the biological impacts of invasive species and on devising management practices that emphasize the health of ecosystems based on measured biological processes. Amur honeysuckle (Lonicera maackii (Rupr.) Herder) is a highly successful invasive shrub in forests of eastern North America. The scientific literature surrounding this species has grown in the past several decades as researchers have investigated L. maackii impacts across multiple ecological scales. In this review we …

Thirty Years Of Compositional Change In An Old-Growth Temperate Forest: The Role Of Topographic Gradients In Oak-Maple Dynamics, Julia I. Chapman, Ryan W. Mcewan

Biology Faculty Publications

Ecological communities are structured in response to spatial and temporal variation of numerous factors, including edaphic conditions, biotic interactions, climatic patterns and disturbance regimes. Widespread anthropogenic factors such as timber harvesting can create long-lasting impacts, obscuring the relationship between community structure and environmental conditions. Minimally impacted systems such as old-growth forests can serve as a useful ecological baseline for predicting long-term compositional shifts. We utilized decadal tree species sampling data (1979–2010) divided into three strata (understory, midstory, overstory) to examine temporal changes in relative abundances and spatial distributions of dominant taxa, as well as overall shifts in community composition, in …

Recovery Of Forest Floor Diversity After Removal Of The Nonnative, Invasive Plant Euonymus Fortunei, Kali Z. Mattingly, Ryan W. Mcewan, Robert D. Paratley, Sarah R. Bray, James R. Lempke, Mary A. Arthur

Biology Faculty Publications

The vine Euonymus fortunei (Turcz.) Hand.-Mazz. is invading forests of the eastern United States; as a result, removal of E. fortunei has become a priority of resource managers. This study examined the effectiveness of five techniques for eliminating E. fortunei, restoring plant species richness, and enhancing recolonization by woody species. In 2003, the following five treatments were applied: burn with a propane torch, light exclusion by plastic tarp, burn and glyphosate application, cut (simulated grazing) and glyphosate application, mow and glyphosate application, plus an untreated control. Each treatment was replicated four times in a randomized block design located in …

Microbial Biofilm Community Variation In Flowing Habitats: Potential Utility As Bioindicators Of Postmortem Submersion Intervals, Jennifer M. Lang, Racheal Erb, Jennifer L. Pechal, John R. Wallace, Ryan W. Mcewan, Mark Eric Benbow

Biology Faculty Publications

Biofilms are a ubiquitous formation of microbial communities found on surfaces in aqueous environments. These structures have been investigated as biomonitoring indicators for stream heath, and here were used for the potential use in forensic sciences. Biofilm successional development has been proposed as a method to determine the postmortem submersion interval (PMSI) of remains because there are no standard methods for estimating the PMSI and biofilms are ubiquitous in aquatic habitats. We sought to compare the development of epinecrotic (biofilms on Sus scrofa domesticus carcasses) and epilithic (biofilms on unglazed ceramic tiles) communities in two small streams using bacterial automated …

Control Of Partitioning And Export Of Carbon In Leaves Of Higher-Plants, Donald R. Geiger

Biology Faculty Publications

Within source leaves, partition of assimilated carbon and export are regulated to both leaf and plant ontogeny and to environmental conditions. System goals, adaptive responses, control mechanisms, and information flow are developed from the viewpoint that a well-adapted plant is an integrated system. Regulation of partitioning and export involves both feedforward control and feedback homeostasis. Export is controlled by regulation of metabolism which supplies assimilated material to be translocated, by control of efflux into the free space of material destined for export, and by regulation of phloem loading. Control of export by the latter two processes depends on responsive metabolic …