Treesearch
Displaying 17,361 - 17,370 of 65,176 Publications- Humid tropical forest soils are characterized by warm temperatures, abundant rainfall, and high rates of biological activity that vary considerably in both space and time. These conditions, together with finely textured soils typical of humid tropical forests lead to periodic low redox conditions, even in well-drained upland environments. The relationship between redox and biogeochemical processes has been studied for decades in saturated environments like wetlands and sediments, but much less is known about redox dynamics in upland soils. The goal of this study was to understand the...AuthorsDaniel Liptzin, Whendee L. SilverSourceEcosphereYear2015
- It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide1. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities2. However, subsequent experimental tests produced mixed results3–13. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilienc...AuthorsForest Isbell, Dylan Craven, John Connolly, Michel Loreau, Bernhard Schmid, Carl Beierkuhnlein, T. Martijn Bezemer, Catherine Bonin, Helge Bruelheide, Enrica de Luca, Anne Ebeling, John N. Griffin, Qinfeng Guo, Yann Hautier, Andy Hector, Anke Jentsch, Jurgen Kreyling, Vojtech Lanta, Pete Manning, Sebastian T. Meyer, Akira S. Mori, Shahid Naeem, Pascal A. Niklaus, H. Wayne Polley, Peter B. Reich, Christiane Roscher, Eric W. Seabloom, Melinda D. Smith, Madhav P. Thakur, David Tilman, Benjamin F. Tracy, Wim H. van der Putten, Jasper van Ruijven, Alexandra Weigelt, Wolfgang W. Weisser, Brian Wilsey, Nico EisenhauerSourceNatureYear2015
- Light use efficiency (LUE) is a key biophysical parameter characterizing the ability of plants to convert absorbed light to carbohydrate. However, the environmental regulations on LUE, especially moisture stress, are poorly understood, leading to large uncertainties in primary productivity estimated by LUE models. The objective of this study is to investigate the effects of moisture stress on LUE for a wide range of ecosystems on daily, 8 day, and monthly scales. Using the FLUXNET and Moderate Resolution Imagine Spectroradiometer data, we evaluated moisture stress along the soil-plant-atmos...AuthorsYulong Zhang, Conghe Song, Ge Sun, Lawrence E. Band, Asko Noormets, Quanfa ZhangSourceJournal of Geophysical Research: BiogeosciencesYear2015
- Aims. Our objective was to assess the impacts of water table position and plant functional groups on peatland extracellular enzyme activity (EEA) framed within the context of the enzymic latch hypothesis. Methods. We utilized a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: Ericaceae, sedge, Ericaceae and sedge unmanipulated) in twenty-four 1 m3 intact peatland mesocosms. We measured bulk peat and porewater phase oxidative and hydrolytic enzyme activities monthly from June - October 2012. We also measured physical and...AuthorsKarl J. Romanowicz, Evan Kane, Lynette Potvin, Aleta L. Daniels, Randy Kolka, Erik LilleskovKeywordsSourcePlant and Soil. 397(1-2): 371-386.Year2015
Fertility-dependent effects of ectomycorrhizal fungal communities on white spruce seedling nutrition
Ectomycorrhizal fungi (EcMF) typically colonize nursery seedlings, but nutritional and growth effects of these communities are only partly understood. To examine these effects, Picea glauca seedlings collected from a tree nursery naturally colonized by three dominant EcMF were divided between fertilized and unfertilized treatments. After one growing season seedlings were harvested, ectomycorrhizas identified using DNA sequencing, and seedlings analyzed for leaf nutrient concentration and content, and biomass parameters. EcMF community structure–nutrient interactions were tested using...AuthorsAlistair J. H. Smith, Lynette Potvin, Erik LilleskovKeywordsSourceMycorrhiza. 25(8): 649-662.Year2015- Pre-dispersal seed predation (PDSP) is commonly observed in woody plants, and recognized as a driver of seed production variability that is critical for successful regeneration. Earlier studies on PDSP and its determinants were mostly species specific, with community- level PDSP rarely estimated; and the interactions between the temporal variability of seed production and PDSP remain elusive. In this study, the community seed rain of woody plants in a mixed evergreen-deciduous broadleaf forest was monitored for seven years. We examined predation on collected seeds and analyzed the determina...AuthorsYue Xu, Zehao Shen, Daoxin Li, Qinfeng GuoSourcePLOS ONEYear2015
Seedfall and seed viability within artificial canopy gaps in a western Washington douglas-fir forest
Seedfall of coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) has been studied at the forest edge-clearcut interface and in small canopy gaps, but it has not been evaluated in gap sizes that would be typical of a group-selection method of regeneration. In a mature Douglas-fir forest in the Puget Sound lowlands of western Washington, seedfall was measured by month in artificially created circular gaps 0.1, 0.2, 0.3, and 0.4 ha (0.25, 0.5, 0.75, and 1.0 ac, respectively) in size and in the forest matrix. Seedfall was assessed 1 year before and 2 years after gap creation,...AuthorsWarren D. Devine, Timothy B. HarringtonKeywordsSourceTree Planter’s Notes: 23-32.Year2015- Although repeated fires are generally thought to reduce competition, direct tests of this hypothesis are rare. Furthermore, recent theory predicts that fires can increase competitive effects of fireresistant species on fire-sensitive species and thus create stable assemblages dominated by the former. In this study, I quantified competition between saplings of fire-resistant oaks and their fire-sensitive non-oak neighbors in adjacent, repeatedly-burned and unburned 1-ha plots following damage by a tornado that reduced canopy cover to 60%. Using field experiments with established in situ...AuthorsJ. Stephen BrewerKeywordsSourceEcosphereYear2015
- This article focuses on the collaborative and voluntary Wilderness Best Management Practices (WBMP) for managing recreation in Tracy Arm-Fords Terror Wilderness in Alaska. Stakeholder definitions of wilderness, opinions about the WBMP, and whether these opinions are reflective of their perceptions of wilderness are examined. Interviews with tour operators, agency personnel, cruise industry representatives, and local residents showed that most expressed some degree of purism in their definitions of wilderness (e.g. solitude and minimal impact), although cruise representatives had less...AuthorsEmily F. Pomeranz, Mark D. Needham, Linda E. KrugerKeywordsSourceManaging Sport and Leisure. 20(1): 36–55. Year2015
- Novel forests (NFs)—forests that contain a combination of introduced and native species—are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual species in those forests. This study focuses on the functional attributes of Castilla elastica NFs in Puerto Rico and on the differences between introduced and native species growing side by side in these...AuthorsJessica Fonseca da SilvaKeywordsSourceEcology and EvolutionYear2015