Forest Sciences Commons^™

Reintroducing Environmental Change Drivers In Biodiversity-Ecosystem Functioning Research., Frederik De Laender, Jason R. Rohr, Roman Ashauer, Donald J Baird, Uta Berger, Nico Eisenhauer, Volker Grimm, Udo Hommen, Lorraine Maltby, Carlos J Meliàn

Integrative Biology Faculty and Staff Publications

For the past 20 years, research on biodiversity and ecosystem functioning (B-EF) has only implicitly considered the underlying role of environmental change. We illustrate that explicitly reintroducing environmental change drivers in B-EF research is needed to predict the functioning of ecosystems facing changes in biodiversity. Next we show how this reintroduction improves experimental control over community composition and structure, which helps to provide mechanistic insight on how multiple aspects of biodiversity relate to function and how biodiversity and function relate in food webs. We also highlight challenges for the proposed reintroduction and suggest analyses and experiments to better understand how …

Linking Hydraulic Traits To Tropical Forest Function In A Size-Structured And Trait-Driven Model (Tfs V.1-Hydro), Bradley O. Christoffersen, Manuel Gloor, Sophie Fauset, Nikolaos M. Fyllas, David R. Galbraith, Timothy R. Baker, Bart Kruij, Lucy Rowland, Rosie A. Fisher, Oliver J. Binks

Biology Faculty Publications and Presentations

Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ε, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata ( …

The Variation Of Productivity And Its Allocation Along A Tropical Elevation Gradient: A Whole Carbon Budget Perspective, Yadvinder Malhi, Cécile A. J. Girardin, Gregory R. Goldsmith, Christopher E. Doughty, Norma Salinas, Daniel B. Metcalfe, Walter Huaraca Huasco, Javier E. Silva-Espejo, Jhon Del Aguilla-Pasquell, Filio Farfán Amézquita, Luiz E.O.C. Aragão, Rossella Guerrieri, Françoise Yoko Ishida, Nur Bahar, William Farfan-Rios, Oliver L. Phillips, Patrick Meir, Miles Silman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

• Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation.
  
  
• We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 3300 m elevation transect in Peru.
  
  
• Low growth rates at high elevations appear primarily driven by low gross primary productivity (GPP), with little shift in either carbon use efficiency (CUE) or allocation of net primary productivity (NPP) between wood, fine roots and canopy. The lack of trend in …

Partitioning Controls On Amazon Forest Photosynthesis Between Environmental And Biotic Factors At Hourly To Interannual Timescales, Jin Wu, Kaiyu Guan, Matthew Hayek, Natalia Restrepo-Coupe, Kenia T. Wiedemann, Xiangtao Xu, Richard Wehr, Bradley O. Christoffersen, Guofang Miao, Rodrigo Da Silva

Biology Faculty Publications and Presentations

Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was …

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 …

Functional Diversity Of Small And Large Trees Along Secondary Succession In A Tropical Dry Forest, Lucía Sanaphre-Villanueva, Juan Manuel Dupuy, José Luis Andrade, Casandra Reyes-García, Horacio Paz, Paula C. Jackson

Faculty Articles

Functional Diversity is considered an important driver of community assembly in environmental and successional gradients. To understand tree assembly processes in a semideciduous tropical forest, we analyzed the variation of Functional Richness (FRic), Functional Divergence (FDiv), and Functional Evenness (FEve) of small vs. large trees in relation to fallow age after slash-and-burn agriculture and topographical position (flat sites vs. hills). FRic of small trees was lower than null model predicted values across the successional gradient, and decreased unexpectedly in older successional ages. FRic of large trees was higher than null model predictions early in succession and lower in late-successional stands …

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 …

Microclimate Variation And Epiphyte Distribution In Acer Macrophylum, Jeremy Wood

Summer Research

Habitat heterogeneity plays a key role in supporting biodiversity in both animals and plant life. More diverse environments provide more exploitable niches across gradients in temperature, humidity, light availability, and countless other variables at the landscape and regional scales. In specimens of Acer macrophylum in the Hoh Rainforest, we found significant variation in temperature and relative humidity across particular crown zones, and certain epiphyte species were found to distribute according to such microclimate variation.

Spatial Distribution Of Earthworms In An East Texas Forest Ecosystem, Melissa A. Bozarth, Kenneth W. Farrish, George A. Damoff, James Van Kley, J. Leon Young

Faculty Publications

Earthworms were collected and identified in different ecological habitats of the Stephen F. Austin Experimental Forest (SFAEF) in the Piney Woods Ecoregion (PWE) of Texas. Earthworm spatial distribution data were collected over four distinct ecological habitats with a range of soil conditions and vegetative cover. A total of 128 sampling plots were surveyed in two different, broadly defined locations (mesic slope = 68 plots, dry-mesic upland = 60 plots). Using multivariate classification/ordination (TWINSPAN) and detrended correspondence analysis (DCA) of overstory vegetation data, these two locations were further divided into four distinct habitats: dry-mesic mixed upland, transitional zone, mesic slope and …

Habitat Use And Avoidance By Foraging Red-Cockaded Woodpeckers In East Texas, John N. Macey, Brent Burt, Daniel Saenz, Richard N. Conner

Faculty Publications

Picoides borealis (Red-cockaded Woodpecker) is an endangered bird endemic to the Pinus (pine) ecosystems of the southeastern US. Mature pine savannahs with a minimal midstory and lush herbaceous groundcover represent high-quality habitat. This study examines the foraging-habitat patterns of Red-cockaded Woodpeckers in East Texas. We present a logistic regression model that best differentiates between foraged and non-foraged habitat. Increases in hardwood-midstory basal area have the greatest negative impact on the probability of Red-cockaded Woodpeckers selecting a habitat patch for foraging. Five additional variables negatively impact foraging probability: shrub height, diameter at breast height (DBH) of pine midstory, canopy closure, density …

Twenty-Five Year Response Of The Herbaceous Layer Of A Temperate Hardwood Forest To Elevated Nitrogen Deposition, Frank S. Gilliam, Nicole Turrill Welch, Anne Hockenberry Phillips, Jake H. Billmyer, William T. Peterjohn, Zachariah K. Fowler, Christopher A. Walter, Mark B. Burnham, Jeffrey D. May, Mary Beth Adams

Biological Sciences Faculty Research

Increasing rates of atmospheric deposition of nitrogen (N) present a novel threat to the biodiversity of terrestrial ecosystems. Many forests are particularly susceptible to excess N given their proximity to sources of anthropogenic N emissions. This study summarizes results of a 25-yr treatment of an entire central Appalachian hardwood forest watershed via aerial applications of N with a focus on effects of added N on the cover, species richness, and composition of the herbaceous layer. Research was carried out on two watersheds of the Fernow Experimental Forest (FEF), West Virginia. The long-term reference watershed at FEF (WS4) was used as …