Treesearch

Evidence of increasing fire extent and severity in the western US in recent decades has raised concern over the effects of fire on threatened species such as the spotted owl (Strix occidentalis Xantus de Vesey), which nests in forests with large trees and high canopy cover that are vulnerable to high-severity wildfire. A dichotomy of views exists on the impact of high-severity wildfire on the spotted owl. One view holds that reduction in the extent of forests with large trees and high canopy cover due to high-severity wildfire is a primary threat to spotted owls, and that fuels reduction...

Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g. white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plant invasion at a few sites, the overarching influence of deer on plant invasion across regional scales is unclear. We tested the effects of deer on the abundance and diversity of introduced and native...

Stake tests are a critical part of evaluating durability of wood in ground-contact, but there is a lack of criteria for interpreting stake test results. This paper discusses criteria that might be used to determine if short term ratings indicate satisfactory longterm performance. Ratings of 19 by 19 mm stakes from multiple plots in the Harrison Experimental Forest, Mississippi, were analyzed to determine how well performance criteria at years three, four, or five predicted durability over the longer term (nine years). Results revealed that with only three years of data, false prediction of...

This study examines the relative roles of cli- matic variables in altering annual runoff in the contermi- nous United States (CONUS) in the 21st century, using a monthly ecohydrological model (the Water Supply Stress In- dex model, WaSSI) driven with historical records and future scenarios constructed from 20 Coupled Model Intercompar- ison Project Phase 5 (CMIP5) climate models. The results suggest that precipitation has been the primary control of runoff variation during the latest decades, but the role of tem- perature will outweigh that of precipitation in most regions if future...

Streamflow is essential for maintaining healthy aquatic ecosystems and for sup- porting human water supply needs. Changes in climate, land use and water use practices may alter water availability. Understanding the potential effect of these changes on aquatic ecosystems is critical for long-term water management to maintain a balance between water for human consumption and ecosystem needs. 2. Fish species data and streamflow estimates from a rainfall-runoff and flow rout- ing model were used to develop boosted regression tree models to predict the relationship between streamflow and fish...

Wetlands store a disproportionately large fraction of organic carbon relative to their areal coverage, and thus play an important role in global climate mitigation. As destabilization of these stores through land use or en- vironmental change represents a signi fi cant climate feedback, it is important to understand the functional regulation of respiratory processes that catabolize them. In this study, we established an eddy covariance fl ux tower project in a coastal plain forested wetland in North Carolina, USA, and measured total ecosystem re- spiration (R e ) over three years (2009 –...

The framework for ecosystem services has been increasingly used in integrated watershed ecosystem management practices that involve scientists, engineers, managers, and policy makers. The objective of this review is to explore the intimate connections between ecohydrological processes and water-related ecosystem services in human-dominated ecosystems in the Anthropocene. We synthesize current literature to illustrate the importance of understanding the ecohydrological processes for accurately quantifying ecosystem services under different environmental and socioeconomic settings and...

The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, ground- water recharge, and wildlife habitat. However, these wet- land ecosystems are dependent on local climate and hydrol- ogy, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydro- logic models for five forested wetlands with different char- acteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cy- press ponds/swamps,...

The critical zone (CZ), the dynamic living skin of the Earth, extends from the top of the vegetative canopy through the soil and down to fresh bedrock and the bottom of the groundwater. All humans live in and depend on the CZ. This zone has three co-evolving surfaces: the top of the vegetative canopy, the ground surface, and a deep subsurface below which Earth’s materials are unweathered. The network of nine CZ observatories supported by the US National Science Foundation has made advances in three broad areas of CZ research relating to the co-evolving surfaces. First, monitoring has...

Introduction: A fundamental challenge to the integrity of tropical dry forest ecosystems is the invasion of nonnative grass species. These grasses compete for resources and fuel anthropogenic wildfires. In 2012, a bulldozer from the Puerto Rico Electric Power Authority cleared a 570-m trail from a state road into a mature dry forest section of Guánica Forest to control a wildfire. We monitored colonization by a non-native invasive grass (Megathyrsus maximus), a highly invasive tree (Leucaena leucocephala), and a native grass (Uniola virgata), as well as natural regeneration, along the...