The Experts below are selected from a list of 2748 Experts worldwide ranked by ideXlab platform
Kristin L. Mercer - One of the best experts on this subject based on the ideXlab platform.
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Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol.
PloS one, 2020Co-Authors: Vivian Bernau, Lev Jardón Barbolla, Leah K. Mchale, Kristin L. MercerAbstract:Responses to drought within a single species may vary based on plant developmental stage, drought severity, and the avoidance or tolerance mechanisms employed. Early drought stress can restrict emergence and seedling growth. Thus, in areas where water availability is limited, rapid germination leading to early plant establishment may be beneficial. Alternatively, germination without sufficient water to support the seedling may lead to early senescence, so reduced germination under low moisture conditions may be adaptive at the level of the population. We studied the germination response to osmotic stress of diverse chile pepper germplasm collected in southern Mexico from varied Ecozones, cultivation systems, and of named landraces. Drought stress was simulated using polyethylene glycol solutions. Overall, survival time analysis revealed delayed germination at the 20% concentration of PEG across all Ecozones. The effect was most pronounced in the genotypes from hotter, drier Ecozones. Additionally, accessions from wetter and cooler Ecozones had the fastest rate of germination. Moreover, accessions of the landraces Costeno Rojo and Tusta germinated more slowly and incompletely if sourced from a drier Ecozone than a wetter one, indicating that slower, reduced germination under drought stress may be an adaptive avoidance mechanism. Significant differences were also observed between named landraces, with more domesticated types from intensive cultivation systems nearly always germinating faster than small-fruited backyard- or wild-types, perhaps due to the fact that the smaller-fruited accessions may have undergone less selection. Thus, we conclude that there is evidence of local adaptation to both Ecozone of origin and source cultivation system in germination characteristics of diverse chile peppers.
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Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol
2020Co-Authors: Vivian Bernau, Lev Jardón Barbolla, Leah K. Mchale, Kristin L. MercerAbstract:Abstract Responses to drought within a single species may vary based on plant development stage, drought severity, and the avoidance or tolerance mechanisms employed. Early drought stress can restrict emergence and seedling growth. Thus, in areas where water availability is limited, rapid germination leading to early plant establishment may be beneficial. Alternatively, germination without sufficient water to support the seedling may lead to early senescence, so reduced germination under low moisture conditions may be adaptive at the level of the population. We studied the germination response to osmotic stress of diverse chile pepper germplasm collected in southern Mexico from varied Ecozones, cultivation systems, and of named landraces. Drought stress was simulated using polyethylene glycol solutions. Overall, survival time analysis revealed delayed germination at the 20% concentration of PEG across all Ecozones. The effect was most pronounced in the genotypes from hotter, drier Ecozones. Additionally, accessions from wetter and cooler Ecozones had the fastest rate of germination. Moreover, accessions of the landraces Costeno Rojo and Tusta germinated more slowly and incompletely if sourced from a drier Ecozone than a wetter one, indicating that slower, reduced germination under drought stress may be an adaptive avoidance mechanism. Significant differences were also observed between named landraces, with more domesticated types from intensive cultivation systems nearly always germinating faster than small-fruited backyard- or wild-types, perhaps due to the fact that the smaller-fruited accessions have generally undergone less selection. Thus, we conclude that there is evidence of local adaptation to both Ecozone of origin and source cultivation system in germination characteristics of diverse chile peppers.
John M. Little - One of the best experts on this subject based on the ideXlab platform.
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Characterization of wildfire regimes in Canadian boreal terrestrial ecosystems
International Journal of Wildland Fire, 2009Co-Authors: Yueyang Jiang, Qianlai Zhuang, Mike D. Flannigan, John M. LittleAbstract:Wildfire is a major disturbance in boreal terrestrial ecosystems. Characterizing fire regimes and projecting fire recurrence intervals for different biomes are important in managing those ecosystems and quantifying carbon dynamics of those ecosystems. This study used Canadian wildfire datasets, 1980-1999, to characterize relationships between number of fires and burned area for 13 Ecozones and to calculate wildfire recurrence intervals in each Ecozone. For the study period, wildfires were found to follow power-law relationships between frequency densities (number of fires normalized to unit bins) and burned areas in all Ecozones. Power-law frequency-area relationships also held for both anthropogenic fires and natural fires in the 1980s and 1990s. For each Canadian Ecozone using the parameters of the power-law frequency-area distributions, fire recurrence intervals were then calculated for wildfires equal to or larger than a given size of burned area. Fire recurrence intervals ranged from 1 to 32 years for burned areas > 2k m 2 , and from 1 to 100 years for burned areas >10 km 2 in every 10 000-km 2 spatial area for each Ecozone. The information obtained through characterizing the wildfires and the fire recurrence intervals calculated in this study will provide guidance to wildfire risk managers throughout Canada. The findings of this study will also be a benefit to future efforts in quantifying carbon dynamics in Canadian boreal terrestrial ecosystems.
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Spatial patterns of forest fires in Canada, 1980-1999
International Journal of Wildland Fire, 2006Co-Authors: Marc-andré Parisien, Vernon S. Peters, Yonghe Wang, John M. Little, Erin M. Bosch, Brian J. StocksAbstract:The present study characterized the spatial patterns of forest fires in 10 fire-dominated Ecozones of Canada by using a database of mapped fires ≥200 ha from 1980 to 1999 (n = 5533 fires). Spatial metrics were used individually to compare measures of fire size, shape (eccentricity and complexity), clustering, and geographic orientation among Ecozones and were used concurrently in a multivariate analysis. In addition, a set of factors that influence the fire regime at the Ecozone level – topography, climate, fuels, and anthropogenic factors – was compared with the metric outputs. We found significant differences in all spatial metrics among Ecozones. The multivariate analysis showed that the Montane Cordillera Ecozone, which covers most of British Columbia, had the most distinctive fires: its fires were smaller, less complex, and had a more regular distribution. The fire regime descriptors of Ecozones were useful to interpret the spatial variation of some spatial metrics, such as fire size, eccentricity, and clustering, but provided little insight into the mechanisms of patterns of fire complexity, which were shown to be sensitive to data quality. Our results provide additional information about the creation of spatially heterogeneous landscapes. Furthermore, they illustrate the potential use of spatial metrics for a more detailed characterization of fire regimes and provide novel information for ecosystems-based land management.
Chris M. Debeer - One of the best experts on this subject based on the ideXlab platform.
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The changing water cycle: the Boreal Plains Ecozone of Western Canada
Wiley Interdisciplinary Reviews: Water, 2015Co-Authors: Andrew Ireson, Alan G. Barr, Jill F. Johnstone, Steven D. Mamet, G. Van Der Kamp, Colin J. Whitfield, Nicole L. Michel, Rebecca L. North, Cherie J. Westbrook, Chris M. DebeerAbstract:The Boreal Plains Ecozone (BPE) in Western Canada is expected to be an area of maximum ecological sensitivity in the 21st century. Successful climate adaptation and sustainable forest management require a better understanding of the interactions between hydrology, climate, and vegetation. This paper provides a perspective on the changing water cycle in the BPE from an interdisciplinary team of researchers, seeking to identify the critical knowledge gaps. Our review suggests the BPE will likely become drier and undergo more frequent disturbance and shifts in vegetation. The forest will contract to the north, though the southern boundary of the ecotone will remain in place. We expect detrimental impacts on carbon sequestration, water quality, wildlife, and water supplies. Ecosystem interactions are complex, and many processes are affected differently by warming and drying, thus the degree and direction of change is often uncertain. However, in the short term at least, human activities are the dominant source of change and are unpredictable but likely decisive. Current climate, hydrological, and ecological monitoring in the BPE are limited and inadequate to understand and predict the complex responses of the BPE to human activities and climate change. This paper provides a case study of how hydrological processes critically determine ecosystem functioning, and how our ability to predict system response is limited by our ability to predict changing hydrology. WIREs Water 2015, 2:505–521. doi: 10.1002/wat2.1098 For further resources related to this article, please visit the WIREs website.
Claudio Provenzani - One of the best experts on this subject based on the ideXlab platform.
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Benthic foraminifera as proxies of marine influence in the Orosei marine caves, Sardinia, Italy
Aquatic Conservation: Marine and Freshwater Ecosystems, 2020Co-Authors: Elena Romano, Luisa Bergamin, Andrea Marassich, Letizia Di Bella, Virgilio Frezza, Giancarlo Pierfranceschi, Claudio ProvenzaniAbstract:As a result of their location at the boundary between marine and continental domains, marine caves are affected by wide spatial and seasonal environmental changes. Only recently have benthic foraminifera been recognized as reliable indicators for the ecological zonation of these environments. The present study is focused on two marine caves of the Orosei Gulf, Sardinia, Italy: Bue Marino and Bel Torrente. It investigates the spatial and seasonal variability of benthic foraminiferal assemblages relative to sediment grain size and water parameters (temperature, salinity, pH, and dissolved oxygen) collected during two campaigns in August 2014 and April 2015. The results from 2014 have been partially published. Based on a comparison of the results of the two campaigns, the considerable reduction of foraminiferal abundance in Bel Torrente was deduced to occur because of the strong freshwater flows occurring during the rainy season; in Bue Marino, the less severe water flow allowed the identification of both living and dead foraminifera, although strongly reduced in number. These identifications allowed benthic foraminifera to be used to define the ecological zonation. Entrance, confluence, and transitional Ecozones were identified in Bue Marino cave on the basis of species abundance. The second Ecozone, not recognized in 2014, was correlated with plant debris at the confluence of the two cave branches. The other two Ecozones, which are characterized by the faunal shift from hyaline‐ to agglutinated‐prevalent assemblages, were attributed to the gradient of abiotic parameters detected from the outer to the inner portions of the cave. In both campaigns the same Ecozones were recognized in terms of species composition, with exceptions being found to different extents as a result of seasonal variability. As the distribution of foraminiferal Ecozones is conditioned by a decreasing gradient of marine influence, long‐term monitoring may be regarded as a promising tool for future studies on sea‐level change.
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Foraminiferal Ecozones in two submarine caves of the Orosei Gulf (Sardinia, Italy)
Rendiconti Lincei. Scienze Fisiche e Naturali, 2018Co-Authors: Luisa Bergamin, Andrea Marassich, Claudio Provenzani, Elena RomanoAbstract:Because submarine caves are affected by wide spatial and temporal environmental variability, they are ideal environments for studying the effects of environmental changes on ecological indicators. Benthic foraminifera are protozoa living in marine and transitional habitats, developing typical assemblages as a response to different environmental conditions. For this, they have been increasingly used as ecological indicators for environmental characterization and monitoring. This study was the first one aimed to compare benthic foraminiferal fauna of two different submarine caves of temperate areas, Bel Torrente and Bue Marino, in the Orosei Gulf (Sardinia, Italy). It resumes the main results obtained in Bel Torrente cave by a previous research, implemented by new data acquired by the study of Bue Marino cave. The caves were surveyed and sampled by GUE (Global Underwater Explorers) divers for the first 450 m to recognize distinct Ecozones, their ecological significance, and to compare them as regards species composition and extent. The succession of Marine, Entrance and Transitional Ecozones was recognized in both the caves. While the Marine Ecozone pointed out environmental conditions very similar to those of shallow water marine environment, the Entrance and Transitional Ecozones indicated increasing environmental stress. In the Entrance Ecozone, the dominance of tolerant species was probably due to the high environmental variability for the episodic high energy floods and, locally, reduced oxygenation events. In the Transitional Ecozone, the decrease of seawater salinity and temperature, especially after rainy periods, probably encouraged the prevalence of agglutinated taxa, which are normally rare in Mediterranean shallow water marine environment, while they are common in high latitude basins.
Vivian Bernau - One of the best experts on this subject based on the ideXlab platform.
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Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol.
PloS one, 2020Co-Authors: Vivian Bernau, Lev Jardón Barbolla, Leah K. Mchale, Kristin L. MercerAbstract:Responses to drought within a single species may vary based on plant developmental stage, drought severity, and the avoidance or tolerance mechanisms employed. Early drought stress can restrict emergence and seedling growth. Thus, in areas where water availability is limited, rapid germination leading to early plant establishment may be beneficial. Alternatively, germination without sufficient water to support the seedling may lead to early senescence, so reduced germination under low moisture conditions may be adaptive at the level of the population. We studied the germination response to osmotic stress of diverse chile pepper germplasm collected in southern Mexico from varied Ecozones, cultivation systems, and of named landraces. Drought stress was simulated using polyethylene glycol solutions. Overall, survival time analysis revealed delayed germination at the 20% concentration of PEG across all Ecozones. The effect was most pronounced in the genotypes from hotter, drier Ecozones. Additionally, accessions from wetter and cooler Ecozones had the fastest rate of germination. Moreover, accessions of the landraces Costeno Rojo and Tusta germinated more slowly and incompletely if sourced from a drier Ecozone than a wetter one, indicating that slower, reduced germination under drought stress may be an adaptive avoidance mechanism. Significant differences were also observed between named landraces, with more domesticated types from intensive cultivation systems nearly always germinating faster than small-fruited backyard- or wild-types, perhaps due to the fact that the smaller-fruited accessions may have undergone less selection. Thus, we conclude that there is evidence of local adaptation to both Ecozone of origin and source cultivation system in germination characteristics of diverse chile peppers.
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Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol
2020Co-Authors: Vivian Bernau, Lev Jardón Barbolla, Leah K. Mchale, Kristin L. MercerAbstract:Abstract Responses to drought within a single species may vary based on plant development stage, drought severity, and the avoidance or tolerance mechanisms employed. Early drought stress can restrict emergence and seedling growth. Thus, in areas where water availability is limited, rapid germination leading to early plant establishment may be beneficial. Alternatively, germination without sufficient water to support the seedling may lead to early senescence, so reduced germination under low moisture conditions may be adaptive at the level of the population. We studied the germination response to osmotic stress of diverse chile pepper germplasm collected in southern Mexico from varied Ecozones, cultivation systems, and of named landraces. Drought stress was simulated using polyethylene glycol solutions. Overall, survival time analysis revealed delayed germination at the 20% concentration of PEG across all Ecozones. The effect was most pronounced in the genotypes from hotter, drier Ecozones. Additionally, accessions from wetter and cooler Ecozones had the fastest rate of germination. Moreover, accessions of the landraces Costeno Rojo and Tusta germinated more slowly and incompletely if sourced from a drier Ecozone than a wetter one, indicating that slower, reduced germination under drought stress may be an adaptive avoidance mechanism. Significant differences were also observed between named landraces, with more domesticated types from intensive cultivation systems nearly always germinating faster than small-fruited backyard- or wild-types, perhaps due to the fact that the smaller-fruited accessions have generally undergone less selection. Thus, we conclude that there is evidence of local adaptation to both Ecozone of origin and source cultivation system in germination characteristics of diverse chile peppers.
