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Articles 151 - 180 of 194
Full-Text Articles in Ecology and Evolutionary Biology
Modeling And Monitoring Terrestrial Primary Production In A Changing Global Environment: Toward A Multiscale Synthesis Of Observation And Simulation, Shufen Pan, Hanqin Tian, Shree R. S. Dangal, Zhiyun Ouyang, Bo Tao, Wei Ren, Chaoqun Lu, Steven W. Running
Modeling And Monitoring Terrestrial Primary Production In A Changing Global Environment: Toward A Multiscale Synthesis Of Observation And Simulation, Shufen Pan, Hanqin Tian, Shree R. S. Dangal, Zhiyun Ouyang, Bo Tao, Wei Ren, Chaoqun Lu, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
There is a critical need to monitor and predict terrestrial primary production, the key indicator of ecosystem functioning, in a changing global environment. Here we provide a brief review of three major approaches to monitoring and predicting terrestrial primary production: (1) ground-based field measurements, (2) satellite-based observations, and (3) process-based ecosystem modelling. Much uncertainty exists in the multi-approach estimations of terrestrial gross primary production (GPP) and net primary production (NPP). To improve the capacity of model simulation and prediction, it is essential to evaluate ecosystem models against ground and satellite-based measurements and observations. As a case, we have shown the …
Ecological Processes Dominate The 13C Land Disequilibrium In A Rocky Mountain Subalpine Forest, D. R. Bowling, Ashley P. Ballantyne, J. B. Miller, S. P. Burns, T. J. Conway, O. Menzer, B. B. Stephens, B. H. Vaughn
Ecological Processes Dominate The 13C Land Disequilibrium In A Rocky Mountain Subalpine Forest, D. R. Bowling, Ashley P. Ballantyne, J. B. Miller, S. P. Burns, T. J. Conway, O. Menzer, B. B. Stephens, B. H. Vaughn
Ecosystem and Conservation Sciences Faculty Publications
Fossil fuel combustion has increased atmospheric CO2 by ≈ 115 µmol mol−1 since 1750 and decreased its carbon isotope composition (δ13C) by 1.7–2‰ (the 13C Suess effect). Because carbon is stored in the terrestrial biosphere for decades and longer, the δ13C of CO2released by terrestrial ecosystems is expected to differ from the δ13C of CO2 assimilated by land plants during photosynthesis. This isotopic difference between land-atmosphere respiration (δR) and photosynthetic assimilation (δA) fluxes gives rise to the 13C land disequilibrium …
Exposure Of U.S. National Parks To Land Use And Climate Change 1900-2100, Andrew J. Hansen, Cory Davis, Jessica Haas, David M. Theobald, John E. Gross, William B. Monahan, Tom Olliff, Steven W. Running
Exposure Of U.S. National Parks To Land Use And Climate Change 1900-2100, Andrew J. Hansen, Cory Davis, Jessica Haas, David M. Theobald, John E. Gross, William B. Monahan, Tom Olliff, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
Many protected areas may not be adequately safeguarding biodiversity from human activities on surrounding lands and global change. The magnitude of such change agents and the sensitivity of ecosystems to these agents vary among protected areas. Thus, there is a need to assess vulnerability across networks of protected areas to determine those most at risk and to lay the basis for developing effective adaptation strategies. We conducted an assessment of exposure of U.S. National Parks to climate and land use change and consequences for vegetation communities. We first defined park protected-area centered ecosystems (PACEs) based on ecological principles. We then …
Consequences Of A Refuge For The Predator-Prey Dynamics Of A Wolf-Elk System In Banff National Park, Alberta, Canada, Joshua F. Goldberg, Mark Hebblewhite, Jonathan M. Bardsley
Consequences Of A Refuge For The Predator-Prey Dynamics Of A Wolf-Elk System In Banff National Park, Alberta, Canada, Joshua F. Goldberg, Mark Hebblewhite, Jonathan M. Bardsley
Wildlife Biology Faculty Publications
Refugia can affect predator-prey dynamics via movements between refuge and non-refuge areas. We examine the influence of a refuge on population dynamics in a large mammal predator-prey system. Wolves (Canis lupus) have recolonized much of their former range in North America, and as a result, ungulate prey have exploited refugia to reduce predation risk with unknown impacts on wolf-prey dynamics. We examined the influence of a refuge on elk (Cervus elaphus) and wolf population dynamics in Banff National Park. Elk occupy the Banff townsite with little predation, whereas elk in the adjoining Bow Valley experience higher wolf predation. The Banff …
Comparison Of Gross Primary Productivity Derived From Gimms Ndvi3g, Gimms, And Modis In Southeast Asia, Junbang Wang, Jingwei Dong, Jiyuan Liu, Mei Huang, Guicai Li, Steven W. Running, William Kolby Smith, Warwick Harris, Nobuko Saigusa, Hiroaki Kondo, Yunfen Liu, Takashi Hirano, Xiangming Xiao
Comparison Of Gross Primary Productivity Derived From Gimms Ndvi3g, Gimms, And Modis In Southeast Asia, Junbang Wang, Jingwei Dong, Jiyuan Liu, Mei Huang, Guicai Li, Steven W. Running, William Kolby Smith, Warwick Harris, Nobuko Saigusa, Hiroaki Kondo, Yunfen Liu, Takashi Hirano, Xiangming Xiao
Ecosystem and Conservation Sciences Faculty Publications
Gross primary production (GPP) plays an important role in the net ecosystem exchange of CO2 between the atmosphere and terrestrial ecosystems. It is particularly important to monitor GPP in Southeast Asia because of increasing rates of tropical forest degradation and deforestation in the region in recent decades. The newly available, improved, third generation Normalized Difference Vegetation Index (NDVI3g) from the Global Inventory Modelling and Mapping Studies (GIMMS) group provides a long temporal dataset, from July 1981 to December 2011, for terrestrial carbon cycle and climate response research. However, GIMMS NDVI3g-based GPP estimates are not yet available. We applied the GLOPEM-CEVSA …
Insights Into The Development And Evolution Of Exaggerated Traits Using De Novo Transcriptomes Of Two Species Of Horned Scarab Beetles, Ian A. Warren, J. Cristobal Vera, Annika Johns, Robert Zinna, James H. Marden, Douglas J. Emlen, Ian Dworkin, Laura C. Lavine
Insights Into The Development And Evolution Of Exaggerated Traits Using De Novo Transcriptomes Of Two Species Of Horned Scarab Beetles, Ian A. Warren, J. Cristobal Vera, Annika Johns, Robert Zinna, James H. Marden, Douglas J. Emlen, Ian Dworkin, Laura C. Lavine
Biological Sciences Faculty Publications
Scarab beetles exhibit an astonishing variety of rigid exo-skeletal outgrowths, known as ‘‘horns’’. These traits are often sexually dimorphic and vary dramatically across species in size, shape, location, and allometry with body size. In many species, the horn exhibits disproportionate growth resulting in an exaggerated allometric relationship with body size, as compared to other traits, such as wings, that grow proportionately with body size. Depending on the species, the smallest males either do not produce a horn at all, or they produce a disproportionately small horn for their body size. While the diversity of horn shapes and their behavioural ecology …
A Conceptual Framework For Clutch-Size Evolution In Songbirds, Thomas E. Martin
A Conceptual Framework For Clutch-Size Evolution In Songbirds, Thomas E. Martin
Wildlife Biology Faculty Publications
Causes of evolved differences in clutch size among songbird species remain debated. I propose a new conceptual framework that integrates aspects of traditional life-history theory while including novel elements to explain evolution of clutch size among songbirds. I review evidence that selection by nest predation on length of time that offspring develop in the nest creates a gradient in offspring characteristics at nest leaving (fledging), including flight mobility, spatial dispersion, and self-feeding rate. I postulate that this gradient has consequences for offspring mortality rates and parental energy expenditure per offspring. These consequences then determine how reproductive effort is partitioned among …
Invasive Plant Erodes Local Song Diversity In A Migratory Passerine, Yvette K. Ortega, Aubree Benson, Erick Greene
Invasive Plant Erodes Local Song Diversity In A Migratory Passerine, Yvette K. Ortega, Aubree Benson, Erick Greene
Biological Sciences Faculty Publications
Exotic plant invasions threaten ecosystems globally, but we still know little about the specific consequences for animals. Invasive plants can alter the quality of breeding habitat for songbirds, thereby impacting important demographic traits such as dispersal, philopatry, and age structure. These demographic effects may in turn alter song-learning conditions to affect song structure and diversity. We studied Chipping Sparrows (Spizella passerina) breeding in six savannas that were either dominated by native vegetation or invaded by spotted knapweed (Centaurea stoebe), an exotic forb known to diminish food resources and reproductive success. Here, we report that the prevalence of older birds was …
Changes To Snowpack Energy State From Spring Storm Events, Columbia River Headwaters, Montana, Zachary M. Seligman, Joel T. Harper, Marco P. Maneta
Changes To Snowpack Energy State From Spring Storm Events, Columbia River Headwaters, Montana, Zachary M. Seligman, Joel T. Harper, Marco P. Maneta
Geosciences Faculty Publications
The generation and release of meltwater during the spring snowmelt season can be delayed because of spring storm episodes with snow accumulation and/or sustained subfreezing temperatures. The delayed release of snowmelt often extends beyond the particular storm event because of changes to the internal state of energy in the snowpack that prevents transmission of meltwater. Following a storm, two energy deficits internal to the snowpack must be overcome before surface melt can drain and exit the snowpack: 1) cold content created by heat lost during the episode must be removed and 2) dry pore space must be filled with liquid …
Developmental Link Between Sex And Nutrition; Doublesex Regulates Sex-Specific Mandible Growth Via Juvenile Hormone Signaling In Stag Beetles, Hiroki Gotoh, Hitoshi Miyakawa, Asano Ishikawa, Yuki Ishikawa, Yasuhiro Sugime, Douglas J. Emlen, Laura C. Lavine, Toru Miura
Developmental Link Between Sex And Nutrition; Doublesex Regulates Sex-Specific Mandible Growth Via Juvenile Hormone Signaling In Stag Beetles, Hiroki Gotoh, Hitoshi Miyakawa, Asano Ishikawa, Yuki Ishikawa, Yasuhiro Sugime, Douglas J. Emlen, Laura C. Lavine, Toru Miura
Biological Sciences Faculty Publications
Sexual dimorphisms in trait expression are widespread among animals and are especially pronounced in ornaments and weapons of sexual selection, which can attain exaggerated sizes. Expression of exaggerated traits is usually male-specific and nutrition sensitive. Consequently, the developmental mechanisms generating sexually dimorphic growth and nutritiondependent phenotypic plasticity are each likely to regulate the expression of extreme structures. Yet we know little about how either of these mechanisms work, much less how they might interact with each other. We investigated the developmental mechanisms of sex-specific mandible growth in the stag beetle Cyclommatus metallifer, focusing on doublesex gene function and its …
Within-Season Nest Reuse By Mountain Plovers (Charadrius Montanus) In Eastern Colorado, Lani T. Stinson, Victoria J. Dreitz
Within-Season Nest Reuse By Mountain Plovers (Charadrius Montanus) In Eastern Colorado, Lani T. Stinson, Victoria J. Dreitz
Wildlife Biology Faculty Publications
The Mountain Plover (Charadrius montanus) is a declining migratory shorebird that nests on shortgrass prairies across the western Great Plains. This ground-nesting species exhibits an uncommon split-clutch mating system, in which each member of a pair simultaneously incubates a nest and uniparental care continues throughout brood-rearing. We report on an observation of within-season nest reuse in this species. To our knowledge, this report includes the first documented occurrence of 2 different Mountain Plovers using the same nest cup in the same breeding season. Nest reuse could represent a time- and energy-saving strategy for renesting individuals.
Habitat Quality Influences Migratory Strategy Of Female White-Tailed Deer, Charles R. Henderson Jr.
Habitat Quality Influences Migratory Strategy Of Female White-Tailed Deer, Charles R. Henderson Jr.
Graduate Student Theses, Dissertations, & Professional Papers
Partial migration is a life history strategy that is common for ungulate species living in seasonal environments. One factor that influences the decision to migrate by ungulates is access to high quality habitat. We evaluated the influence of access to winter habitat of high quality on the probability of an individual migrating, the differences in seasonal habitat use between and within migratory and resident classes of deer, and the effects of this decision on the survival of female white-tailed deer. We hypothesized that deer with home ranges of relatively low quality in winter would have a relatively high probability of …
Disturbed Waters – A Montana Chemist Searches For The Source Of A Persistent Poison, Kindra Mcquillan
Disturbed Waters – A Montana Chemist Searches For The Source Of A Persistent Poison, Kindra Mcquillan
Graduate Student Theses, Dissertations, & Professional Papers
In December 2008, when Montana's great Clark Fork River tested its historic banks for the first time in 100 years, a crowd of hundreds gathered to watch the removal of Milltown Dam at the confluence of the river with the Big Blackfoot. After a century of pollution from Butte's copper mines, the river was undergoing the nation's largestyet restoration project, the Upper Clark Fork River Superfund Complex.
But in a windowless laboratory a mile away, University of Montana chemist Heiko Langner had troubling news. Toxic methylmercury flowed through the river at concentrations of concern, undetected and undermining the project. It …
New Species Of Gondwanamyces From Dying Euphorbia Trees In South Africa, Johannes Alwyn Van Der Linde, Diana Six, Michael J. Wingfield, Jolanda Roux
New Species Of Gondwanamyces From Dying Euphorbia Trees In South Africa, Johannes Alwyn Van Der Linde, Diana Six, Michael J. Wingfield, Jolanda Roux
Ecosystem and Conservation Sciences Faculty Publications
Gondwanamyces and its Custingophora anamorphs were first described from Protea infructescences in South Africa. Subsequently these unusual fungi were also found on Cecropia in Central America. During an investigation into the decline and death of native Euphorbia trees in South Africa, several fungal isolates resembling the anamorph state of Gondwanamyces were obtained from diseased tissues. In this study these isolates are identified based on morphology and comparisons of DNA sequences. Two previously unknown Gondwanamyces species were identified, both were associated with damage caused by beetles (Cossonus sp.). Inoculation studies showed that the new species of Gondwanamyces are pathogenic on Euphorbia …
Satellite Finds Highest Land Skin Temperatures On Earth, David J. Mildrexler, Maosheng Zhao, Steven W. Running
Satellite Finds Highest Land Skin Temperatures On Earth, David J. Mildrexler, Maosheng Zhao, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
The location of the hottest spot on Earth has undoubtedly been an interesting curiosity for centuries. Even with the advent of the instrumental temperature record around the year 1850, the location of the hottest spot on Earth has continued to be the subject of debate and controversy. In 1913, the weather station at Furnace Creek in Death Valley National Park, California, measured an air temperature of 56.7°C (134.1°F) and claimed the title of “hottest place on Earth.” Nine years later in El Azizia, Libya, an air temperature of 57.8°C (136°F) was recorded on land owned by an Italian farmer and …
An Ecosystem-Scale Model For The Spread Of A Host-Specific Forest Pathogen In The Greater Yellowstone Ecosystem, Jaclyn A. Hatala, Michael C. Dietze, Robert L. Crabtree, Katherine Kendall, Diana Six, Paul R. Moorcroft
An Ecosystem-Scale Model For The Spread Of A Host-Specific Forest Pathogen In The Greater Yellowstone Ecosystem, Jaclyn A. Hatala, Michael C. Dietze, Robert L. Crabtree, Katherine Kendall, Diana Six, Paul R. Moorcroft
Ecosystem and Conservation Sciences Faculty Publications
The introduction of nonnative pathogens is altering the scale, magnitude, and persistence of forest disturbance regimes in the western United States. In the high-altitude whitebark pine (Pinus albicaulis) forests of the Greater Yellowstone Ecosystem (GYE), white pine blister rust (Cronartium ribicola) is an introduced fungal pathogen that is now the principal cause of tree mortality in many locations. Although blister rust eradication has failed in the past, there is nonetheless substantial interest in monitoring the disease and its rate of progression in order to predict the future impact of forest disturbances within this critical ecosystem.
This …
Linking Environmental Nutrient Enrichment And Disease Emergence In Humans And Wildlife, Pieter T. J. Johnson, Alan R. Townsend, Cory C. Cleveland, Patricia M. Glibert, Robert W. Howarth, Valerie J. Mckenzie, Eliska Rejmankova, Mary H. Ward
Linking Environmental Nutrient Enrichment And Disease Emergence In Humans And Wildlife, Pieter T. J. Johnson, Alan R. Townsend, Cory C. Cleveland, Patricia M. Glibert, Robert W. Howarth, Valerie J. Mckenzie, Eliska Rejmankova, Mary H. Ward
Ecosystem and Conservation Sciences Faculty Publications
Worldwide increases in human and wildlife diseases have challenged ecologists to understand how large-scale environmental changes affect host–parasite interactions. One of the most profound changes to Earth's ecosystems is the alteration of global nutrient cycles, including those of phosphorus (P) and especially nitrogen (N). Along with the obvious direct benefits of nutrient application for food production, anthropogenic inputs of N and P can indirectly affect the abundance of infectious and noninfectious pathogens. The mechanisms underpinning observed correlations, however, and how such patterns vary with disease type, have long remained conjectural. Here, we highlight recent experimental advances to critically evaluate the …
Experimental Drought In A Tropical Rain Forest Increases Soil Carbon Dioxide Losses To The Atmosphere, Cory C. Cleveland, William R. Wieder, Sasha C. Reed, Alan R. Townsend
Experimental Drought In A Tropical Rain Forest Increases Soil Carbon Dioxide Losses To The Atmosphere, Cory C. Cleveland, William R. Wieder, Sasha C. Reed, Alan R. Townsend
Ecosystem and Conservation Sciences Faculty Publications
Climate models predict precipitation changes for much of the humid tropics, yet few studies have investigated the potential consequences of drought on soil carbon (C) cycling in this important biome. In wet tropical forests, drought could stimulate soil respiration via overall reductions in soil anoxia, but previous research suggests that litter decomposition is positively correlated with high rainfall fluxes that move large quantities of dissolved organic matter (DOM) from the litter layer to the soil surface. Thus, reduced rainfall could also limit C delivery to the soil surface, reducing respiration rates. We conducted a throughfall manipulation experiment to investigate how …
Assemblage Of Hymenoptera Arriving At Logs Colonized By Ips Pini (Coleoptera: Curculionidae: Scolytinae) And Its Microbial Symbionts In Western Montana, Celia K. Boone, Diana Six, Steven J. Krauth, Kenneth F. Raffa
Assemblage Of Hymenoptera Arriving At Logs Colonized By Ips Pini (Coleoptera: Curculionidae: Scolytinae) And Its Microbial Symbionts In Western Montana, Celia K. Boone, Diana Six, Steven J. Krauth, Kenneth F. Raffa
Ecosystem and Conservation Sciences Faculty Publications
Colonization of a tree by bark beetles and their symbionts creates a new habitat for a diverse assemblage of arthropods, including competing herbivores, xylophages, fungivores, saprophages, predators, and parasitoids. Understanding these assemblages is important for evaluating nontarget effects of various management tactics and for subsequently evaluating how changes in climate, the presence of invasive species, and altered forestry practices and land-use tenure may affect biodiversity. We characterized the assemblage of hymenopterans attracted to logs of ponderosa pine (Pinus ponderosa C. Lawson (Pinaceae)) colonized by the bark beetle Ips pini (Say) and its microbial symbionts. In one experiment, the composition and …
Controls Over Leaf Litter Decomposition In Wet Tropical Forests, William R. Wieder, Cory C. Cleveland, Alan R. Townsend
Controls Over Leaf Litter Decomposition In Wet Tropical Forests, William R. Wieder, Cory C. Cleveland, Alan R. Townsend
Ecosystem and Conservation Sciences Faculty Publications
Tropical forests play a substantial role in the global carbon (C) cycle and are projected to experience significant changes in climate, highlighting the importance of understanding the factors that control organic matter decomposition in this biome. In the tropics, high temperature and rainfall lead to some of the highest rates of litter decomposition on earth, and given the near-optimal abiotic conditions, litter quality likely exerts disproportionate control over litter decomposition. Yet interactions between litter quality and abiotic variables, most notably precipitation, remain poorly resolved, especially for the wetter end of the tropical forest biome. We assessed the importance of variation …
Transport Of Fungal Symbionts By Mountain Pine Beetles, K. P. Bleiker, S. E. Potter, C. R. Lauzon, Diana Six
Transport Of Fungal Symbionts By Mountain Pine Beetles, K. P. Bleiker, S. E. Potter, C. R. Lauzon, Diana Six
Ecosystem and Conservation Sciences Faculty Publications
The perpetuation of symbiotic associations between bark beetles (Coleoptera: Curculionidae: Scolytinae) and ophiostomatoid fungi requires the consistent transport of fungi by successive beetle generations to new host trees. We used scanning electron microscopy and culture methods to investigate fungal transport by the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins. MPB transports its two main fungal associates, Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield and Ophiostoma montium (Rumbold) von Arx, in sac-like mycangia on the maxillary cardines as well as on the exoskeleton. Although spores of both species of fungi were observed on MPB exoskeletons, often in pits, …
Detection Of Host Habitat By Parasitoids Using Cues Associated With Mycangial Fungi Of The Mountain Pine Beetle, Dendroctonus Ponderosae, A. S, Adams, Diana Six
Detection Of Host Habitat By Parasitoids Using Cues Associated With Mycangial Fungi Of The Mountain Pine Beetle, Dendroctonus Ponderosae, A. S, Adams, Diana Six
Ecosystem and Conservation Sciences Faculty Publications
Cues used by parasitoids to detect habitat of the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), were investigated by observing parasitoid attraction to logs infested with D. ponderosae, logs inoculated with one or both of the symbiotic fungi of D. ponderosae (Grosmannia clavigera (Rob.-Jeffr. & R.W. Davidson) Zipfel, Z.W. de Beer & M.J. Wingf. (Ophiostomataceae) and Ophiostoma montium (Rumbold) Arx (Ophiostomataceae)), logs containing no beetles or fungi, or empty screen cylinders. Captures of Heydenia unica Cook and Davis (Hymenoptera: Pteromalidae) and Rhopalicus pulchripennis (Crawford) (Hymenoptera: Pteromalidae) on logs with both G. clavigera and O. montium were greater than those …
Tree Species Control Rates Of Free-Living Nitrogen Fixation In A Tropical Rain Forest, Sasha C. Reed, Cory C. Cleveland, Alan R. Townsend
Tree Species Control Rates Of Free-Living Nitrogen Fixation In A Tropical Rain Forest, Sasha C. Reed, Cory C. Cleveland, Alan R. Townsend
Ecosystem and Conservation Sciences Faculty Publications
Tropical rain forests represent some of the most diverse ecosystems on earth, yet mechanistic links between tree species identity and ecosystem function in these forests remains poorly understood. Here, using free-living nitrogen (N) fixation as a model, we explore the idea that interspecies variation in canopy nutrient concentrations may drive significant local-scale variation in biogeochemical processes. Biological N fixation is the largest “natural” source of newly available N to terrestrial ecosystems, and estimates suggest the highest such inputs occur in tropical ecosystems. While patterns of and controls over N fixation in these systems remain poorly known, the data we do …
A New Satellite-Based Methodology For Continental-Scale Disturbance Detection, David J. Mildrexler, Maosheng Zhao, Faith Ann Heinsch, Steven W. Running
A New Satellite-Based Methodology For Continental-Scale Disturbance Detection, David J. Mildrexler, Maosheng Zhao, Faith Ann Heinsch, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
The timing, location, and magnitude of major disturbance events are currently major uncertainties in the global carbon cycle. Accurate information on the location, spatial extent, and duration of disturbance at the continental scale is needed to evaluate the ecosystem impacts of land cover changes due to wildfire, insect epidemics, flooding, climate change, and human-triggered land use. This paper describes an algorithm developed to serve as an automated, economical, systematic disturbance detection index for global application using Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua Land Surface Temperature (LST) and Terra/MODIS Enhanced Vegetation Index (EVI) data from 2003 to 2004. The algorithm is based …
Sensitivity Of Pan-Arctic Terrestrial Net Primary Productivity Simulations To Daily Surface Meterology From Ncep-Ncar And Era-40 Reanalyses, Ke Zhang, John S. Kimball, Maosheng Zhao, Walter C. Oechel, John Cassano, Steven W. Running
Sensitivity Of Pan-Arctic Terrestrial Net Primary Productivity Simulations To Daily Surface Meterology From Ncep-Ncar And Era-40 Reanalyses, Ke Zhang, John S. Kimball, Maosheng Zhao, Walter C. Oechel, John Cassano, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
We applied a terrestrial net primary production (NPP) model driven by satellite remote sensing observations of vegetation properties and daily surface meteorology from the 45-year ECMWF Re-Analysis (ERA-40) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP-NCAR) reanalysis (NNR) to assess NPP spatial and temporal variability for the pan-Arctic basin and Alaska from 1982 to 2000. Sensitivity analysis of the production efficiency model (PEM) to uncertainties in surface meteorological inputs indicate that ERA-40 solar radiation and NNR solar radiation and surface temperatures are the primary sources of PEM-based NPP uncertainty for the region. Considerable positive bias in …
Biogeochemical Consequences Of Rapid Microbial Turnover And Seasonal Succession In Soil, S. K. Schmidt, E. K. Costello, D. R. Nemergut, Cory C. Cleveland, S. C. Reed, M. N. Weintraub, A. F. Meyer, A. M. Martin
Biogeochemical Consequences Of Rapid Microbial Turnover And Seasonal Succession In Soil, S. K. Schmidt, E. K. Costello, D. R. Nemergut, Cory C. Cleveland, S. C. Reed, M. N. Weintraub, A. F. Meyer, A. M. Martin
Ecosystem and Conservation Sciences Faculty Publications
Soil microbial communities have the metabolic and genetic capability to adapt to changing environmental conditions on very short time scales. In this paper we combine biogeochemical and molecular approaches to reveal this potential, showing that microbial biomass can turn over on time scales of days to months in soil, resulting in a succession of microbial communities over the course of a year. This new understanding of the year-round turnover and succession of microbial communities allows us for the first time to propose a temporally explicit N cycle that provides mechanistic hypotheses to explain both the loss and retention of dissolved …
Controls Over Foliar N:P Ratios In Tropical Rain Forests, Alan R. Townsend, Cory C. Cleveland, Gregory P. Asner, Mercedes M. C. Bustamante
Controls Over Foliar N:P Ratios In Tropical Rain Forests, Alan R. Townsend, Cory C. Cleveland, Gregory P. Asner, Mercedes M. C. Bustamante
Ecosystem and Conservation Sciences Faculty Publications
Correlations between foliar nutrient concentrations and soil nutrient availability have been found in multiple ecosystems. These relationships have led to the use of foliar nutrients as an index of nutrient status and to the prediction of broadscale patterns in ecosystem processes. More recently, a growing interest in ecological stoichiometry has fueled multiple analyses of foliar nitrogen : phosphorus (N:P) ratios within and across ecosystems. These studies have observed that N:P values are generally elevated in tropical forests when compared to higher latitude ecosystems, adding weight to a common belief that tropical forests are generally N rich and P poor. However, …
3-Pg Productivity Modeling Of Regenerating Amazon Forests: Climate Sensitivity And Comparison With Modis-Derived Npp, Joseph D. White, Neal A. Scott, Adam I. Hirsch, Steven W. Running
3-Pg Productivity Modeling Of Regenerating Amazon Forests: Climate Sensitivity And Comparison With Modis-Derived Npp, Joseph D. White, Neal A. Scott, Adam I. Hirsch, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
Potential forest growth predicted by the Physiological Principles in Predicting Growth (3-PG) model was compared for forest and deforested areas in the Legal Amazon to assess potential differing regeneration associated with climate. Historical deforestation and regeneration have occurred in environmentally marginal areas that influence regional carbon sequestration estimates. Effects of El Niño–induced drought further reduce simulated production by decreasing soil water availability in areas with shallow soils and high transpiration potential. The model was calibrated through comparison of literature biomass and with satellite-based estimates. Net primary productivity (NPP) for mature Amazonian forests from the 3-PG model was positively correlated ( …
Estimation Of Incident Photosynthetically Active Radiation From Moderate Resolution Imaging Spectrometer Data, Shunlin Liang, Tao Zheng, Ronggao Liu, Hongliang Fang, Si-Chee Tsay, Steven W. Running
Estimation Of Incident Photosynthetically Active Radiation From Moderate Resolution Imaging Spectrometer Data, Shunlin Liang, Tao Zheng, Ronggao Liu, Hongliang Fang, Si-Chee Tsay, Steven W. Running
Ecosystem and Conservation Sciences Faculty Publications
Incident photosynthetically active radiation (PAR) is a key variable needed by almost all terrestrial ecosystem models. Unfortunately, the current incident PAR products estimated from remotely sensed data at spatial and temporal resolutions are not sufficient for carbon cycle modeling and various applications. In this study, the authors develop a new method based on the look-up table approach for estimating instantaneous incident PAR from the polar-orbiting Moderate Resolution Imaging Spectrometer (MODIS) data. Since the top-of-atmosphere (TOA) radiance depends on both surface reflectance and atmospheric properties that largely determine the incident PAR, our first step is to estimate surface reflectance. The approach …
Nutrient Regulation Of Organic Matter Decomposition In A Tropical Rain Forest, Cory C. Cleveland, Sasha C. Reed, Alan R. Townsend
Nutrient Regulation Of Organic Matter Decomposition In A Tropical Rain Forest, Cory C. Cleveland, Sasha C. Reed, Alan R. Townsend
Ecosystem and Conservation Sciences Faculty Publications
errestrial biosphere–atmosphere CO2 exchange is dominated by tropical forests, so understanding how nutrient availability affects carbon (C) decomposition in these ecosystems is central to predicting the global C cycle's response to environmental change. In tropical rain forests, phosphorus (P) limitation of primary production and decomposition is believed to be widespread, but direct evidence is rare. We assessed the effects of nitrogen (N) and P fertilization on litter-layer organic matter decomposition in two neighboring tropical rain forests in southwest Costa Rica that are similar in most ways, but that differ in soil P availability. The sites contain 100–200 tree species …