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1
Le, Ba Huy. "ECOZONING FOR THE AQUATIC PRODUCTION IN 8 COSTAL ZONE PROVINCES OF MEKONG DELTA". Science and Technology Development Journal 13, n. 1 (30 marzo 2010): 35–47. http://dx.doi.org/10.32508/stdj.v13i1.2079.
Testo completoAbstract (sommario):
Planning for the aquatic production needs the suitable Eco-planning. Such eco-should come from research results of GIS, RS method and direct survey of land use, soil characteristics, water flood level, salinity, acidity, topography, trial, social characteristic. The research on ecozoning for Mekong Delta show that within 8 costal provinces there are many Ecozone which include: Province Sóc trăng: 5 Eco-zones, Bac Lieu: 6 ecozones, Cà Mau: 8 Ecozones ; Kiên Giang: 7 Ecozones, Long An: 5 Ecozones, Tiền Giang: 7 Ecozones, Bến Tre: 6 Ecozones and̀ Trà Vinh: 6 Ecozones. The research also provides the Ecozoning Mapping of the aquatic Production for 8 provinces with the scale of 1/250 000; 1/50/000 and 1/100 000.
2
Hamid, Mohamed E., Adil Mahgoub, Abdulrhman J. O. Babiker, Hussein A. E. Babiker, Mohammed A. I. Holie, Mogahid M. Elhassan e Martin R. P. Joseph. "Isolation and Identification of Streptomyces spp. from Desert and Savanna Soils in Sudan". International Journal of Environmental Research and Public Health 17, n. 23 (25 novembre 2020): 8749. http://dx.doi.org/10.3390/ijerph17238749.
Testo completoAbstract (sommario):
The purpose of this study was to investigate streptomycete populations in desert and savanna ecozones in Sudan and to identify species based on 16S rRNA gene sequences. A total of 49 different Streptomyces phenotypes (22 from sites representing the desert and semi-desert ecozone; 27 representing the savanna ecozone) have been included in the study. The isolates were characterized phenotypically and confirmed using 16S rRNA gene sequence analysis. The two ecozones showed both similarities and uniqueness in the types of isolates. The shared species were in cluster 1 (Streptomyces (S.) werraensis), cluster 2 (Streptomyces sp.), cluster 3 (S. griseomycini-like), and cluster 7 (S. rochei). The desert ecozone revealed unique species in cluster 9 (Streptomyces sp.) and cluster 10 (S. griseomycini). Whereas, the savanna ecozone revealed unique species in cluster 4 (Streptomyces sp.), cluster 5 (S. albogriseolus/ S. griseoincarnatus), cluster 6 (S. djakartensis), and cluster 8 (Streptomyces sp.). Streptomycetes are widely distributed in both desert and the savanna ecozones and many of these require full descriptions. Extending knowledge on Streptomyces communities and their dynamics in different ecological zones and their potential antibiotic production is needed.
3
Hulley, Mike, Colin Clarke e Ed Watt. "Occurrence and magnitude of low flows for Canadian rivers: an ecozone approach". Canadian Journal of Civil Engineering 41, n. 1 (gennaio 2014): 1–8. http://dx.doi.org/10.1139/cjce-2013-0300.
Testo completoAbstract (sommario):
Low-flow occurrence and magnitude have been documented for Canada using the National Ecological Framework. The low flow database is composed of the 7-day low flow with 2-year return period (7Q2) values for 453 natural flow hydrometric stations with record lengths of at least 30 years; drainage areas ranged from 10 to 30 000 km2. Occurrence zones corresponding to predominant season for annual low flows are associated with ecozones. The ecozone scale was found to be suitable for regional analysis for several ecozones. For some ecozones there were insufficient data for regional analysis and for others finer resolution is required. Regional regression equations were developed for estimating 7Q2 in terms of area for ecozones containing at least 20 stations. The results of this work will help practitioners to identify the season of low flow occurrence and the appropriate method of analysis, and provide a means of estimating 7Q2 for ungauged sites for some ecozones.
4
Parisien, Marc-André, Vernon S. Peters, Yonghe Wang, John M. Little, Erin M. Bosch e Brian J. Stocks. "Spatial patterns of forest fires in Canada, 1980 - 1999". International Journal of Wildland Fire 15, n. 3 (2006): 361. http://dx.doi.org/10.1071/wf06009.
Testo completoAbstract (sommario):
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.
5
Dai, Mulan, Luke D. Bainard, Chantal Hamel, Yantai Gan e Derek Lynch. "Impact of Land Use on Arbuscular Mycorrhizal Fungal Communities in Rural Canada". Applied and Environmental Microbiology 79, n. 21 (30 agosto 2013): 6719–29. http://dx.doi.org/10.1128/aem.01333-13.
Testo completoAbstract (sommario):
ABSTRACTThe influence of land use on soil bio-resources is largely unknown. We examined the communities of arbuscular mycorrhizal (AM) fungi in wheat-growing cropland, natural areas, and seminatural areas along roads. We sampled the Canadian prairie extensively (317 sites) and sampled 20 sites in the Atlantic maritime ecozone for comparison. The proportions of the different AM fungal taxa in the communities found at these sites varied with land use type and ecozones, based on pyrosequencing of 18S rRNA gene (rDNA) amplicons, but the lists of AM fungal taxa obtained from the different land use types and ecozones were very similar. In the prairie, the Glomeraceae family was the most abundant and diverse family of Glomeromycota, followed by the Claroideoglomeraceae, but in the Atlantic maritime ecozone, the Claroideoglomeraceae family was most abundant. In the prairie, species richness and Shannon's diversity index were highest in roadsides, whereas cropland had a higher degree of species richness than roadsides in the Atlantic maritime ecozone. The frequencies of occurrence of the different AM fungal taxa in croplands in the prairie and Atlantic maritime ecozones were highly correlated, but the AM fungal communities in these ecozones had different structures. We conclude that the AM fungal resources of soils are resilient to disturbance and that the richness of AM fungi under cropland management has been maintained, despite evidence of a structural shift imposed by this type of land use. Roadsides in the Canadian prairie are a good repository for the conservation of AM fungal diversity.
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Bernau, Vivian M., Lev Jardón Barbolla, Leah K. McHale e Kristin L. Mercer. "Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol". PLOS ONE 15, n. 11 (16 novembre 2020): e0236001. http://dx.doi.org/10.1371/journal.pone.0236001.
Testo completoAbstract (sommario):
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 Costeño 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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ΣΙΝΕΚΟΓΛΟΥ, Α., Α. ΜΑΡΚΟΠΟΥΛΟΥ-ΔΙΑΚΑΝΤΩΝΗ e Ο. DRAGASTAN. "The contribution of the ecozones to the ecostratigraphy. As an example the Plio - Pleistocene basin of Magoula- Karatoulas (Ilia, NE Peloponnesos)". Bulletin of the Geological Society of Greece 34, n. 2 (1 agosto 2018): 593. http://dx.doi.org/10.12681/bgsg.17107.
Testo completoAbstract (sommario):
In this paper is marked the contribution of the Ecozones to the Ecostratigraphy. As an example we use the drillings (Ml, M2, M3, M4, M6, MIO) coming from the Plio- Pleistocene basin of the Magoula- Karatoulas (Pyrgos, Peloponnesus). Based on the detailed stratigraphical and paleoecological studies of the postalpine sediments (VAGIAS et al. 1995) of the formation of Vounargo (HAGEMAN 1977,1979 & ΚΑΜΠΕΡΗΣ 1987) we attempt to define 15 ecozones, as it is understood the layer or the whole of the layers, which is characterized by an association of fossils (at the level of species, genus or family). The Ecozone reflects the evolution of a sedimentary basin from the bathymetrical point of view as well as the transgressions and the regressions. The Ecozones are often related with the curve of the change of the sea level. The transgression is characterized by the rich fossil associations (species and individuals), while the regression is characterized by a diminution of species and individuals. There are also 11 white spots, which can not be enclosed in Ecozones. They are observed in the drillings M2, M3, M4, M6 and MIO.
8
Denysyk, Hryhoriy I., Oksana M. Valchuk-Orkusha, Viktoriia V. Kanska, Volodymyr S. Kanskyi e Iryna P. Kozynska. "Ecozones of road landscape-engineer systems: structure, typology, significance". Journal of Geology, Geography and Geoecology 31, n. 4 (8 gennaio 2023): 591–600. http://dx.doi.org/10.15421/112255.
Testo completoAbstract (sommario):
We analyzed one of the inseparable components of road landscapes of Ukraine, their ecozones. As noted, road landscapes are divided into three categories: road landscape-en- gineer systems (RLESs), road landscape-technogenic systems (RLTSs) and road landscapes proper (RLP). Depending on those categories of road landscapes, there form respective road ecozones. Most distinctively, they become structured and developed over the process of constructing and functioning of RLESs. Therefore, the objectives of our research were the structure, typology, properties and significance of ecozones, mostly those of road landscape-engineer systems for the purpose of their rational exploitation. The objects of the research were RLESs of Ternopil-Khemel- nytskyi-Vinnytsia-Uman-Kropyvnytskyi (M-12) and Kyiv-Odesa (M-5). The research was carried out using the basic principles of landscape science – emergence, cause and effect relationships, history, comparability; methods of analysis, synthesis, modeling, map- ping, GIS-technologies using the software: graphic editors CorelDRAW and Adobe Photoshop, and also open-source network of satellite images Google Earth and other. The notion of road ecozone is considered as a complex ecological structure that is formed and developed over the process of functioning of road landscapes. In more details, we have analyzed the ecozones of modern road landscape-engineer systems M-12 and M-5 which have long been actively operating. Field landscape-science-oriented and ecological studies of ecozones of those RLESs over the period of 2019-2021 made it possible to distinguish and substantiate ten microecozones in their structure. Their specific features are conditioned by specifics of the structure and ecologic condition of previous landscape complexes – the fundamentals of modern RLESs; spatial-temporal specifics of the formation; «linear» spread; dependence on the func- tioning of one type of transport (automobile) and purpose. The features of microecozones are conditioned by land allocated to roads, technical impact, chemical contamination, contamination of soil, aquatic and air contaminations, acoustic and lighting impacts, and esthetic and landscape contaminations. Over the process of further studies, it is possible to distinguish other microecozones, specifically those of biotic and geological impacts, and also uniting certain microecozones into groups. We analyzed one of typical features of road ecozones – their asymmetry. We distinguished and characterized three types of asymmetry of road ecozones – wind-caused, orographic and landscape asymmetries. Not always do their vectors of development coincide. We should note that over the process of functioning of RLTSs and SRLs, there also develop roadside ecozones with respective set of microecozones, though they need additional studies. Further study of ecozones in road landscapes would allow for more thorough planning and forming of their structure, functioning, im- pact on human health and environment. Road landscapes of any category need to be re-constructed into a system of complex purpose – transport, scientific, recreational and esthetic.
9
Jiang, Yueyang, Qianlai Zhuang, Mike D. Flannigan e John M. Little. "Characterization of wildfire regimes in Canadian boreal terrestrial ecosystems". International Journal of Wildland Fire 18, n. 8 (2009): 992. http://dx.doi.org/10.1071/wf08096.
Testo completoAbstract (sommario):
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 >2 km2, and from 1 to 100 years for burned areas >10 km2 in every 10 000-km2 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.
10
García-Montero, Luis G., Cristina Pascual, Alfonso Sanchez-Paus Díaz, Susana Martín-Fernández, Pablo Martín-Ortega, Fernando García-Robredo, Carlos Calderón-Guerrero, Chiara Patriarca e Danilo Mollicone. "Land Use Sustainability Monitoring: “Trees Outside Forests” in Temperate FAO-Ecozones (Oceanic, Continental, and Mediterranean) in Europe (2000–2015)". Sustainability 13, n. 18 (11 settembre 2021): 10175. http://dx.doi.org/10.3390/su131810175.
Testo completoAbstract (sommario):
The global distribution of forest trees is essential for monitoring land-use sustainability. For this reason, FAO developed the Global Forest Survey (GFS), a systematic regional level survey with a homogeneous sampling design. Preliminary results revealed an interest in analyzing “Trees Outside Forests” (TOFs). We analyzed more than 11,150 sample GFS plots in temperate FAO-ecozones in Europe through a photo-interpretation approach using FAO’s Collect Earth platform. Our results showed that forest land was the most predominant use of land (41%) in temperate FAO-ecozones in Europe in 2015. Forest IPCC land use followed a moderate upward trend from 2000 to 2015 (0.2%). Trees Outside Forests in temperate FAO-ecozones in Europe accounted for 22% of the inventoried area. Trees Outside Forests represent 30% and 48% of cropland and grassland IPCC land uses, respectively, as well as 75% in settlement uses. Comparing our results with previous studies on the Mediterranean, temperate FAO-ecozone TOFs showed a downward trend in Europe and an upward trend in the Mediterranean area, despite its smaller surface area. The greening of the Common Agricultural Policy may increase the extension of TOFs, although our results may indicate that this effect is not yet evident in the field.
11
Bremond, Laurent, Christopher Carcaillet, Charly Favier, Adam A. Ali, Cédric Paitre, Yves Bégin, Yves Bergeron e Pierre J. H. Richard. "Effects of vegetation zones and climatic changes on fire-induced atmospheric carbon emissions: a model based on paleodata". International Journal of Wildland Fire 19, n. 8 (2010): 1015. http://dx.doi.org/10.1071/wf09096.
Testo completoAbstract (sommario):
An original method is proposed for estimating past carbon emissions from fires in order to understand long-term changes in the biomass burning that, together with vegetation cover, act on the global carbon cycle and climate. The past carbon release resulting from paleo-fires during the Holocene is examined using a simple linear model between measured carbon emissions from modern fires and sedimentary charcoal records of biomass burning within boreal and cold temperate forests in eastern Canada (Quebec, Ontario). Direct carbon emissions are estimated for each ecozone for the present period and the fire anomaly per kilo annum (ka) v. present day (0 ka) deduced from charcoal series of 46 lakes and peats. Over the postglacial, the Taiga Shield ecozone does not match the pattern of fire history and carbon release of Boreal Shield, Atlantic Maritime, and Mixedwood Plains ecozones. This feature results from different air mass influences and the timing of vegetation dynamics. Our estimations show, first, that the contribution of the Mixedwood Plains and the Atlantic Maritime ecozones on the total carbon emissions by fires remains negligible compared with the Boreal Shield. Second, the Taiga Shield plays a key role by maintaining important carbon emissions, given it is today a lower contributor.
12
Asong, Z. E., S. Razavi, H. S. Wheater e J. S. Wong. "Evaluation of Integrated Multisatellite Retrievals for GPM (IMERG) over Southern Canada against Ground Precipitation Observations: A Preliminary Assessment". Journal of Hydrometeorology 18, n. 4 (27 marzo 2017): 1033–50. http://dx.doi.org/10.1175/jhm-d-16-0187.1.
Testo completoAbstract (sommario):
Abstract The Global Precipitation Measurement (GPM) mission offers new opportunities for modeling a range of physical/hydrological processes at higher resolutions, especially for remote river systems where the hydrometeorological monitoring network is sparse and weather radar is not readily available. In this study, the recently released Integrated Multisatellite Retrievals for GPM [version 03 (V03) IMERG Final Run] product with high spatiotemporal resolution of 0.1° and 30 min is evaluated against ground-based reference measurements (at the 6-hourly, daily, and monthly time scales) over different terrestrial ecozones of southern Canada within a 23-month period from 12 March 2014 to 31 January 2016. While IMERG and ground-based observations show similar regional variations of mean daily precipitation, IMERG tends to overestimate higher monthly precipitation amounts over the Pacific Maritime ecozone. Results from using continuous as well as categorical skill metrics reveal that IMERG shows more satisfactory agreement at the daily and the 6-hourly time scales for the months of June–September, unlike November–March. In terms of precipitation extremes (defined by the 75th percentile threshold for reference data), apart from a tendency toward overdetection of heavy precipitation events, IMERG captured well the distribution of heavy precipitation amounts and observed wet/dry spell length distributions over most ecozones. However, low skill was found over large portions of the Montane Cordillera ecozone and a few stations in the Prairie ecozone. This early study highlights a potential applicability of V03 IMERG Final Run as a reliable source of precipitation estimates in diverse water resources and hydrometeorological applications for different regions in southern Canada.
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Kihara, Job, F. Kizito, M. Jumbo, M. Kinyua e M. Bekunda. "Unlocking maize crop productivity through improved management practices in northern Tanzania". African Journal of Food, Agriculture, Nutrition and Development 20, n. 07 (18 dicembre 2020): 17095–112. http://dx.doi.org/10.18697/ajfand.95.17965.
Testo completoAbstract (sommario):
Addressing the problem of low crop productivity and food insecurity can be accelerated through community-centered implementation of good agricultural management practices. This study was conducted in Babati,Northern Tanzania. The objective of the study was to determine nitrogen (N)and phosphorus (P)application requirements for maize,and demonstrate economically viable best bet yield-improving management technologies under three ecozones namely; ‘low elevation low rainfall’, ‘medium elevation high rainfall’ and ‘medium elevation low rainfall’ ecozone. Two sets of trials were conducted: N (0, 45, 90, 120 and 150 kg ha-1) and P (0, 15, 30, 40 kg ha-1) response trials in 16 representative fields in three seasons of 2013/14, 2014/205 and 2015/16 and; demonstrations trials in 8 farmer-selected fields in 2015/16 season. Combined N and P application increased maize yields by 32 to 62% over single nutrient applications.In the medium elevation low rainfall ecozone, 60-86%yield response to nitrogen was observed.Largely, modest applications of 50 kg N ha-1and 20 kg P ha-1resultedin profitable (marginal rate of return (MRR) of 2.4 to 3.0) yield increases of upto 214% over the farmers practice (unfertilized), varying with variety and ecozone. The source of P (DAP or Minjingu Mazao) had little influence on maize productivity except under low altitude low rainfall where Minjingu Mazao is unprofitable. Farmer rankings and agronomic indices showed new maize hybrids namely Meru H513, Meru H515 and SC627 as priority across the ecozones; Mams H913 is suitable mainly in medium elevation low rainfall ecozone. The conclusion is that use of new maize hybrids and appropriate rates of locally available N and P nutrient sources can bridge existing yield gaps and reduce food insecurity. Technologies from community-driven research in development are easily adopted by a large number of farmers and could result in a quick,yet lasting productivity gains.
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Thomas Ambadan, Jaison, Matilda Oja, Ze’ev Gedalof e Aaron A. Berg. "Satellite-Observed Soil Moisture as an Indicator of Wildfire Risk". Remote Sensing 12, n. 10 (12 maggio 2020): 1543. http://dx.doi.org/10.3390/rs12101543.
Testo completoAbstract (sommario):
Wildfires are a concerning issue in Canada due to their immediate impact on people’s lives, local economy, climate, and environment. Studies have shown that the number of wildfires and affected areas in Canada has increased during recent decades and is a result of a warming and drying climate. Therefore, identifying potential wildfire risk areas is increasingly an important aspect of wildfire management. The purpose of this study is to investigate if remotely sensed soil moisture products from the Soil Moisture and Ocean Salinity (SMOS) satellite can be used to identify potential wildfire risk areas for better wildfire management. We used the National Fire Database (NFDB) fire points and polygons to group the wildfires according to ecozone classifications, as well as to analyze the SMOS soil moisture data over the wildfire areas, between 2010–2017, across fourteen ecozones in Canada. Timeseries of 3-day, 5-day, and 7-day soil moisture anomalies prior to the onset of each wildfire occurrence were examined over the ecozones individually. Overall, the results suggest, despite the coarse-resolution, SMOS soil moisture products are potentially useful in identifying soil moisture anomalies where wildfire hot-spots may occur.
15
Alix, Hugo, Gaëtan F. Tremblay, Martin H. Chantigny, Gilles Bélanger, Philippe Seguin, Keith D. Fuller, Shabtai Bittman et al. "Forage yield, nutritive value, and ensilability of sweet pearl millet and sweet sorghum in five Canadian ecozones". Canadian Journal of Plant Science 99, n. 5 (1 ottobre 2019): 701–14. http://dx.doi.org/10.1139/cjps-2019-0031.
Testo completoAbstract (sommario):
Sweet pearl millet [Pennisetum glaucum (L.) R. Br.] and sweet sorghum [Sorghum bicolor (L.) Moench], previously tested for ethanol production, were evaluated as high sugar crops for animal feeds to possibly replace silage corn (Zea mays L.). We compared the forage yield, nutritive value, and ensilability of one hybrid of sweet pearl millet and two of sweet sorghum to a locally adapted silage corn hybrid in five Canadian ecozones. Forage yields of sweet pearl millet and sorghum were similar to that of silage corn in the Boreal Shield, Mixedwood Plain, and Atlantic Maritime ecozones, greater in the Prairies, and lower in the Pacific Maritime ecozone. Across sites, forage dry matter concentration was less for sweet pearl millet (289 g kg−1) and sweet sorghum (245 g kg−1) than for silage corn (331 g kg−1). Sweet pearl millet had a lower total digestible nutrient (TDN) concentration (452 g kg−1 DM) and aNDF digestibility (NDFd) than sweet sorghum and silage corn along with greater neutral detergent fibre (aNDF) and water-soluble carbohydrate (WSC) concentrations than silage corn. Sweet sorghum had greater aNDF and WSC, lower starch, and similar TDN (534 g kg−1 DM) concentrations, but greater NDFd compared with silage corn. Sweet pearl millet and sorghum fermented as well as silage corn, reaching low pH values and acceptable concentrations of lactic and volatile fatty acids. Sweet sorghum is therefore a viable alternative to silage corn in Canada except in the Pacific Maritime ecozone, but early-maturing hybrids with acceptable DM concentration at harvest are required.
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González Sánchez, Patricia María, Otávio Luis Marques da Silva, Rubén Cabrera, Beatriz Martínez Daranas, Enrique Reynaldo de la Cruz, Valéria Cassano e Mutue Toyota Fujii. "Similarity and areas of endemism of the Laurencia complex (Ceramiales, Rhodomelaceae) in Cuba". Anales de Biología, n. 44 (4 luglio 2022): 55–70. http://dx.doi.org/10.6018/analesbio.44.06.
Testo completoAbstract (sommario):
Las especies del complejo Laurencia son elementos importantes en la estructura y diversidad de los ecosistemas costeros. Por primera vez, se analiza la distribución geográfica del complejo dentro de la plataforma cubana, sus áreas marinas protegidas y se identifican áreas potenciales endémicas, considerando las ecozonas en que se dividió la plataforma. A la fecha, se han inventariado 19 especies, de estas 10 pertenecen a Laurencia, una a Osmundea, cinco a Palisada, dos a Yuzurua, y se incorporó Laurenciella como nuevo género para Cuba. La distribución fue desigual, con un alto número de especies y puntos de ocurrencia, especialmente en las regiones Occidental y Central de la costa norte. El análisis de parsimonia de endemicidad indicó dos ecozonas, una en Habana-Matanzas y otra en la Costa Nordeste, sustentadas por tres y dos especies endémicas, respectivamente. Species of the Laurencia complex are important elements in the structure and diversity of coastal ecosystems. For the first time, we analyzed the geographical distribution of the complex within the Cuban shelf, its marine protected areas and identified potential endemic areas, considering the ecozones into which the shelf was divided. To date, 19 species have been inventoried, of which 10 belong to Laurencia, one to Osmundea, five to Palisada, two to Yuzurua, and Laurenciella a new record of genus for Cuba. The distribution was uneven, with a high number of species and occurrence points, especially in the Western and Central regions of the northern coast. The parsimony analysis of endemicity indicated two ecozones, one in Habana-Matanzas and the other in the Northeast Coast, supported by three and two endemic species, respectively.
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Clair, Thomas A., James Ehrman e Kaz Higuchi. "Changes to the runoff of Canadian ecozones under a doubled CO2 atmosphere". Canadian Journal of Fisheries and Aquatic Sciences 55, n. 11 (1 novembre 1998): 2464–77. http://dx.doi.org/10.1139/f98-129.
Testo completoAbstract (sommario):
Increases in atmospheric greenhouse gases may change the hydrology of a number of Canada's regions. This will have an impact on aquatic and wetland ecosystems as well as municipal, industrial, and power generation uses. It is thus important to get an estimate of the potential changes to the Canadian hydrological cycle in order to make intelligent decisions concerning mitigation factors that society may be forced to undertake. We divided Canada into ecoclimatologically similar regions called "ecozones." We developed two month-stepped temperature-precipitation-runoff models for the country using an artificial intelligence neural network (ANN) approach. We modified input temperature and precipitation variables in the ANN models to match those predicted by the Canadian Climate Centre General Circulation Model II for a doubled CO2 atmosphere and calculated new monthly equilibrium runoff predictions. Our results predict that much of Canada will experience higher annual runoff than is currently the case. The timing of runoff will change significantly in a number of the ecozones, as we show that in many regions, peak runoff will occur approximately 1 month earlier than is currently the case. The ANN model did not work as well for basins in the Prairie ecozone, as we could not develop a good model with data from regulated rivers.
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Amiro, B. D., A. Cantin, M. D. Flannigan e W. J. de Groot. "Future emissions from Canadian boreal forest fires". Canadian Journal of Forest Research 39, n. 2 (febbraio 2009): 383–95. http://dx.doi.org/10.1139/x08-154.
Testo completoAbstract (sommario):
New estimates of greenhouse gas emissions from Canadian forest fires were calculated based on a revised model for fuel consumption, using both the fire fuel load and the Drought Code of the Canadian Forest Fire Weather Index System. This model was applied to future climate scenarios of 2×CO2 and 3×CO2 environments using the Canadian Global Climate Model. Total forest floor fuel consumption for six boreal ecozones was estimated at 60, 80, and 117 Tg dry biomass for the 1×CO2, 2×CO2, and 3×CO2 scenarios, respectively. These ecozones cover the boreal and taiga regions and account for about 86% of the total fire consumption for Canada. Almost all of the increase in fuel consumption for future climates is caused by an increase in the area burned. The effect of more severe fuel consumption density (kilograms of fuel consumed per square metre) is relatively small, ranging from 0% to 18%, depending on the ecozone. The emissions of greenhouse gases from all Canadian fires are estimated to increase from about 162 Tg·year–1 of CO2 equivalent in the 1×CO2 scenario to 313 Tg·year–1 of CO2 equivalent in the 3×CO2 scenario, including contributions from CO2, CH4, and N2O.
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Amiro, B. D., J. B. Todd, B. M. Wotton, K. A. Logan, M. D. Flannigan, B. J. Stocks, J. A. Mason, D. L. Martell e K. G. Hirsch. "Direct carbon emissions from Canadian forest fires, 1959-1999". Canadian Journal of Forest Research 31, n. 3 (1 marzo 2001): 512–25. http://dx.doi.org/10.1139/x00-197.
Testo completoAbstract (sommario):
Direct emissions of carbon from Canadian forest fires were estimated for all Canada and for each ecozone for the period 19591999. The estimates were based on a data base of large fires for the country and calculations of fuel consumption for each fire using the Canadian Forest Fire Behaviour Prediction System. This technique used the fire locations and start dates to estimate prevailing fire weather and fuel type for each of about 11 000 fires. An average of 2 × 106 ha·year1 was burned in this period, varying from 0.3 × 106 ha in 1978 to 7.5 × 106 ha in 1989. Ecozones of the boreal and taiga areas experienced the greatest area burned, releasing most of the carbon (C). The mean area-weighted fuel consumption for all fires was 2.6 kg dry fuel·m2 (1.3 kg C·m2), but ecozones vary from 1.8 to 3.9 kg dry fuel·m2. The mean annual estimate of direct carbon emissions was 27 ± 6 Tg C·year1. Individual years ranged from 3 to 115 Tg C·year1. These direct fire emissions represent about 18% of the current carbon dioxide emissions from the Canadian energy sector, on average, but vary from 2 to 75% among years. Post-fire effects cause an additional loss of carbon and changes to the forest sink condition.
20
Fang, Xing, e John W. Pomeroy. "Diagnosis of future changes in hydrology for a Canadian Rockies headwater basin". Hydrology and Earth System Sciences 24, n. 5 (28 maggio 2020): 2731–54. http://dx.doi.org/10.5194/hess-24-2731-2020.
Testo completoAbstract (sommario):
Abstract. Climate change is anticipated to impact the hydrology of the Saskatchewan River, which originates in the Canadian Rockies mountain range. To better understand the climate change impacts in the mountain headwaters of this basin, a physically based hydrological model was developed for this basin using the Cold Regions Hydrological Modelling platform (CRHM) for Marmot Creek Research Basin (∼9.4 km2), located in the Front Ranges of the Canadian Rockies. Marmot Creek is composed of ecozones ranging from montane forests to alpine tundra and alpine exposed rock and includes both large and small clearcuts. The model included blowing and intercepted snow redistribution, sublimation, energy-balance snowmelt, slope and canopy effects on melt, Penman–Monteith evapotranspiration, infiltration to frozen and unfrozen soils, hillslope hydrology, streamflow routing, and groundwater components and was parameterised without calibration from streamflow. Near-surface outputs from the 4 km Weather Research and Forecasting (WRF) model were bias-corrected using the quantile delta mapping method with respect to meteorological data from five stations located from low-elevation montane forests to alpine ridgetops and running over October 2005–September 2013. The bias-corrected WRF outputs during a current period (2005–2013) and a future pseudo global warming period (PGW, 2091–2099) were used to drive model simulations to assess changes in Marmot Creek's hydrology. Under a “business-as-usual” forcing scenario, Representative Concentration Pathway 8.5 (RCP8.5) in PGW, the basin will warm up by 4.7 ∘C and receive 16 % more precipitation, which will lead to a 40 mm decline in seasonal peak snowpack, 84 mm decrease in snowmelt volume, 0.2 mm d−1 slower melt rate, and 49 d shorter snow-cover duration. The alpine snow season will be shortened by almost 1.5 months, but at some lower elevations there will be large decreases in peak snowpack (∼45 %) in addition to a shorter snow season. Declines in the peak snowpack will be much greater in clearcuts than under mature forest canopies. In alpine and treeline ecozones, blowing snow transport and sublimation will be suppressed by higher-threshold wind speeds for transport, in forest ecozones, sublimation losses from intercepted snow will decrease due to faster unloading and drip, and throughout the basin, evapotranspiration will increase due to a longer snow-free season and more rainfall. Runoff will begin earlier in all ecozones, but, as a result of variability in surface and subsurface hydrology, forested and alpine ecozones will generate the greatest runoff volumetric increases, ranging from 12 % to 25 %, whereas the treeline ecozone will have a small (2 %) decrease in runoff volume due to decreased melt volumes from smaller snowdrifts. The shift in timing in streamflow will be notable, with 236 % higher flows in spring months and 12 % lower flows in summer and 13 % higher flows in early fall. Overall, Marmot Creek's annual streamflow discharge will increase by 18 % with PGW, without a change in its streamflow generation efficiency, despite its basin shifting from primarily snowmelt runoff towards rainfall-dominated runoff generation.
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Afanasieva, M. S. "Devonian Radiolarian Ecozones of Northern Eurasia". Paleontological Journal 54, n. 9 (dicembre 2020): 947–1093. http://dx.doi.org/10.1134/s0031030120090014.
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Coogan, Sean C. P., Xinli Cai, Piyush Jain e Mike D. Flannigan. "Seasonality and trends in human- and lightning-caused wildfires ≥ 2 ha in Canada, 1959–2018". International Journal of Wildland Fire 29, n. 6 (2020): 473. http://dx.doi.org/10.1071/wf19129.
Testo completoAbstract (sommario):
We examined the seasonal distribution of lightning- and human-caused wildfires ≥ 2ha in Canada for two time periods: 1959–2018 and 1981–2018. Furthermore, we investigated trends in seasonality, number of fires per year and number of days with fire starts per year for human- and lightning-caused fires. Nationally, lightning fires peaked from June to August, whereas human fires peaked during May. There was, however, notable variation in the seasonal distributions of human- and lightning-caused fires between ecozones. Likewise, trends in season start and end dates varied among ecozones and time series, with trends generally being stronger for human-caused fires. Trends in the number of fires from 1959 to 2018 suggested significant increases in the number of lightning-caused fires and days with lightning ignitions across almost all ecozones, while from 1981 to 2018 there was a significantly decreasing trend in the number of human-caused fires and days with human ignitions in almost all ecozones. The highest densities of human-caused fires occurred in the Montane Cordillera and Atlantic Maritime, while the highest density of lightning-caused fires occurred in the Boreal Shield West. The Montane Cordillera and Taiga Shield West showed significant increases in the number of lightning fires and days with lightning ignitions across both time series.
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Klos, Ryan J., G. Geoff Wang, Qing-Lai Dang e Ed W. East. "Taper Equations for Five Major Commercial Tree Species in Manitoba, Canada". Western Journal of Applied Forestry 22, n. 3 (1 luglio 2007): 163–70. http://dx.doi.org/10.1093/wjaf/22.3.163.
Testo completoAbstract (sommario):
Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.
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Baafi, Ernest, Mavis Akom, Adelaide Agyeman, Cynthia Darko e Ted Carey. "Breeding farmer and consumer preferred sweetpotatoes using accelerated breeding scheme and mother–baby trials". Open Agriculture 5, n. 1 (21 settembre 2020): 548–57. http://dx.doi.org/10.1515/opag-2020-0055.
Testo completoAbstract (sommario):
AbstractIncreased sweetpotato utilization has become an important breeding objective recently, with much emphasis on the development of non-sweet sweetpotatoes for income and food security in Ghana. The objective of this study was to evaluate 26 elite non-sweet and less sweet sweetpotato genotypes with regard to their release as commercial varieties using mother–baby trial. The 26 sweetpotato genotypes were tested multilocational on-farm across five ecozones from 2016 to 2017. These genotypes were selected from accelerated breeding scheme carried out from 2010 to 2013. There were no year-by-ecozone-by-genotype and year-by-ecozone interactions. However, ecozone-by-genotype interaction was significant for storage root dry matter, beta-carotene, iron and zinc content. This implies that the relative performance of the genotypes for storage root yield was stable across locations and years. Genotypic differences were found for all the traits and indicated that selection of superior genotypes across ecozone was possible. Storage root yield ranged from 7 t/ha to 39 t/ha, while dry matter content ranged from 34% to 46%. The storage root cooking quality preference was comparable with farmers’ check. Ten superior genotypes were identified for release as commercial varieties based on their staple-preferred taste, higher storage root yield, higher dry matter content, earliness, resistance to the sweetpotato virus, sweetpotato weevil and Alcidodes.
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Triantaphyllou, M. V., A. Antonarakou, K. Kouli, M. Dimiza, G. Kontakiotis, P. Ziveri, G. Mortyn, V. Lykousis e M. D. Dermitzakis. "PLANKTON ECOSTRATIGRAPHY AND POLLEN ASSEMBLAGE ZONES OVER THE LAST 14 000 YEARS IN SE AEGEAN SEA (CORE NS-14)". Bulletin of the Geological Society of Greece 40, n. 1 (8 giugno 2018): 209. http://dx.doi.org/10.12681/bgsg.16515.
Testo completoAbstract (sommario):
A quantitative analysis of coccolithophores, planktonic foraminifera and pollen assemblages was carried out on core NS-14 (SE Aegean Sea), recovered in the Western Kos Basin. Eleven coccolithophore (ACE 1-11) and ten planktonic foraminifera (APFE1-10) ecozones have been recognized during the last 14 000 yrs using calcareous nannofossil and planktonic foraminifera abundances. Additionally eight pollen assemblage zones (PAZ 1-8) have been recognised. The established high resolution ecozonal scheme allows a detailed paleoecological reconstruction for the Holocene archive in the SE Aegean Sea, defining two warm and humid phases (9300-8600 yr caiBP and 7600-6400 yr caiBP) associated with the deposition of SI and a third one between 5200-4200 yr ca[BP.
26
Mitchell, A. K., e C. Lee. "The Forest Ecosystem Research Network of Sites (FERNS)". Forestry Chronicle 75, n. 3 (1 giugno 1999): 481–82. http://dx.doi.org/10.5558/tfc75481-3.
Testo completoAbstract (sommario):
The Canadian Forest Service (CFS) has organized a National Forest Ecosystem Research Network of Sites (FERNS). These sites are focussed on the study of sustainable forest management practices and ecosystem processes at the stand level. Network objectives are to promote this research nationally and internationally, provide linkages among sites, preserve the long-term research investments already made on these sites and provide a forum for information exchange and data sharing. The 17 individual sites are representative of six ecozones across Canada and address the common issue of silvicultural solutions to problems of sustainable forest management. While the CFS coordinates and promotes FERNS, the network consists of local autonomous partners nationwide who benefit from the FERNS affiliation through increased publicity for their sites. Key words: long-term, silviculture, network, interdisciplinary, ecozone, ecosystem processes
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Batal, Malek, Hing Man Chan, Karen Fediuk, Amy Ing, Peter Berti, Tonio Sadik e Louise Johnson-Down. "Importance of the traditional food systems for First Nations adults living on reserves in Canada". Canadian Journal of Public Health 112, S1 (giugno 2021): 20–28. http://dx.doi.org/10.17269/s41997-020-00353-y.
Testo completoAbstract (sommario):
Abstract Objective To describe the traditional food (TF) systems of First Nations in Canada, including intake, barriers and promoters. Methods The First Nations Food, Nutrition and Environment Study is a cross-Canada participatory study of First Nations adults below the 60th parallel that obtained data for communities excluded from other national studies. A food frequency questionnaire was used to establish frequency of TF intake (number of days in a year) to allow comparisons across ecozones/regions in Canada. Grams of TF intake were also calculated using frequency multiplied by average portions from 24-h recalls. Closed- and open-ended questions attempted to identify some of the key barriers and concerns regarding TF access and use. Multivariable analyses were run to determine what factors are associated with increased TF consumption. Results Across communities, there is a strong preference by adults to have TF in the diet more often. Consumption of land animals was most frequently reported in most ecozones except for the Pacific Maritime and Mixedwood Plains, where fish and plants, respectively, were more frequently consumed. First Nations identified structural and environmental challenges such as development, government regulations and climate change, along with household barriers such as insufficient capital for equipment and transportation, lack of time and absence of a hunter in the household. Multivariable analyses revealed that the highest intake of TF occurred in the Taiga Plains ecozone, and for older individuals and men. Conclusion Identifying solutions that empower First Nations at all levels is required to overcome the multiple challenges to the inclusion of TF in the diet.
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Zimmer, V. "Konversion der US-Stützpunkte auf den Philipinen : Kompensationsstrategien in militärdominierten Regionalökonomien". Geographica Helvetica 59, n. 1 (31 marzo 2004): 20–29. http://dx.doi.org/10.5194/gh-59-20-2004.
Testo completoAbstract (sommario):
Abstract. Der sehr kurzfristige Abzug der US-Streitkräfte im Jahr 1992 versetzte die Philippinen in die Situation, den Verlust von rund 14.000 Arbeitsplätzen für einheimische Beschäftigte und ein Ausgabevolumen der US-Armee von jährlich mehr als 700 Mio. US$ kompensieren zu müssen. Die gut ausgebaute Infrastruktur der verlassenen US-Stützpunkte sowie die Finanzierung über einen revolvierenden Fonds, dessen Erlöse sich aus der Entwicklung und dem Verkauf großer Militärareale der philippinischen Streitkräfte in der Hauptstadtregion generieren, haben einen zügigen Beginn der Liegenschaftskonversion ermöglicht. Die Zahl der heute in den Konversions-Ecozones geschaffenen neuen Arbeitsplätze übersteigt mittlerweile die Beschäftigung zu Zeiten der US-Streitkräfte bei weitem. Trotzdem bleibt die Entwicklung noch weit von den visionären Vorstellungen der anfänglichen Euphorie entfernt und die Stabilität der heutigen Branchenstruktur ist kritisch zu bewerten. Ein Vergleich der «Konversions-Ecozones» mit den anderen philippinischen Freihandelszonen zeigt jedoch auch, dass diese grundlegend anders strukturiert sind und insbesondere auch kleinere, philippinische Unternehmen in den «Konversions-Ecozones» eine Zugangsmöglichkeit zu einer Freihandelszone finden.
29
Breivik, Heidi M., e Martin Callanan. "Hunting High and Low: Postglacial Colonization Strategies in Central Norway between 9500 and 8000 cal BC". European Journal of Archaeology 19, n. 4 (2016): 571–95. http://dx.doi.org/10.1080/14619571.2016.1147315.
Testo completoAbstract (sommario):
In this article, we examine aspects of the Postglacial colonization processes that took place in central Norway during the Early Mesolithic (c. 9500–8000 cal bc). The distribution of sites from this period shows that the colonizers approached and exploited two very different landscapes and resource situations—from archipelagic to alpine. Based on twelve artefact assemblages from central Norway we investigate how colonizing populations met the challenge posed by varying ecozones. Did they organize their settlements and technologies in similar ways or did they modify sites and activities in relation to the different locations? The aspects studied are site organization, artefact composition, projectiles, and lithic raw material use. It appears that the sites are of a similar size and structure across ecozones. Apart from some variations in tool composition, there is no evidence in the lithic material for any technical adaptation towards specific ecozones. We conclude that using a standard, generalized lithic technology, combined with high mobility and small group size, enabled the colonizing groups to overcome the risks and difficulties associated with settling and seeking out resources in new and unknown landscapes.
30
Erb, John, Nils Chr Stenseth e Mark S. Boyce. "Geographic variation in population cycles of Canadian muskrats (Ondatra zibethicus)". Canadian Journal of Zoology 78, n. 6 (1 giugno 2000): 1009–16. http://dx.doi.org/10.1139/z00-027.
Testo completoAbstract (sommario):
We investigated the dynamic properties of population cycles in Canadian muskrats (Ondatra zibethicus). Ninety-one historic time series of muskrat-harvest data obtained from the Hudson's Bay Company Archives were analyzed. Most series were 25 years in length (19251949) and were distributed primarily throughout five ecozones. For each series, we estimated period length and coefficients for a second-order autoregressive model. Estimated period length varied between 3 and 13 years, with 3- to 5-year periods located in Subarctic-Arctic ecozones. We hypothesize that the 4-year cycles are largely a result of predation by red fox (Vulpes vulpes), which exhibit 4-year cycles in Arctic regions. The remaining ecozones generally averaged 89 years in period length. However, the relative contributions of direct and delayed density dependence varied along a latitudinal gradient. We hypothesize that both social and trophic interactions are necessary to produce the observed dynamics, but that shifts in the nature of mink predation were responsible for the changes in the relative contribution of direct and delayed density dependence. Essentially, there is a tension between population-intrinsic and trophic interactions that may bound the length of the cycle.
31
Beniamovski, Vladimir N. "Paleocene benthic foraminiferal ecozones of the northern Peri-Tethys". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 234, n. 1-3 (22 dicembre 2004): 183–99. http://dx.doi.org/10.1127/njgpa/234/2004/183.
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Molot, L. A., W. Keller, P. R. Leavitt, R. D. Robarts, M. J. Waiser, M. T. Arts, T. A. Clair et al. "Risk analysis of dissolved organic matter-mediated ultraviolet B exposure in Canadian inland waters". Canadian Journal of Fisheries and Aquatic Sciences 61, n. 12 (1 dicembre 2004): 2511–21. http://dx.doi.org/10.1139/f04-165.
Testo completoAbstract (sommario):
With depleted ozone levels and the possibility that climate change might lower dissolved organic matter (DOM) concentrations, the risk of exposure of fresh waters in Canada to ultraviolet B (UV-B) was evaluated. First, the distribution of a UV-B-sensitive zooplankton genus, Daphnia, was examined as a function of DOM concentration and maximum depth (Zmax) in 258 systems. Distribution was not restricted by UV-B, although very clear, shallow systems are underrepresented. Secondly, the depth at which 1% of surface radiance at 320 nm occurs (Z320,1%) was compared with Zmax in over 1000 aquatic systems in 15 ecozones to determine the proportions of optically clear systems (Zmax ≤ Z320,1%) and systems that may become clear (i.e., are "at risk") should DOM decrease by 50%. South of the treeline, <6% of systems were clear, with the exception of two ecozones with 10%20%. The proportion of systems at risk was 0% in most regions, with 5%9% in four regions. DOM levels appear adequate to prevent extirpation of sensitive taxa like Daphnia through direct exposure to UV-B in most regions south of the treeline. However, optically clear and at-risk ponds were much more common in the three Artic ecozones, especially the Northern Arctic and Arctic Cordillera.
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Titova, Lyubov’, Abdulmonem Hassan, Ivan Mikhailov, Elena Rodionova, Sergei Rasskazov e Мarina Usoltseva. "Diversity and Ecology of Diatoms in Pliocene Deposits of the Tunka Valley (Baikal Rift Zone)". Diversity 13, n. 10 (29 settembre 2021): 479. http://dx.doi.org/10.3390/d13100479.
Testo completoAbstract (sommario):
Fossil diatoms are an excellent tool for reconstructing the palaeoenvironmental and palaeogeographic changes involving lacustrine systems. In this work, the diatom content of Pliocene sediments recovered from a core extracted in the Tunka Basin (Baikal Rift Zone, Russia) is described. Revealed by light and scanning electron microscopy, 170 species of diatoms were found. Benthic, alkaliphilic, indifferent, cosmopolitan, and oligosaprobe species predominated. Ecological, geographical, and stratigraphic analysis of diatoms showed two ecozones, differing in taxonomic diversity of species. From the data obtained, palaeoenvironmental conditions of these zone formations have been reconstructed. It was shown that during the period corresponding to sedimentation in Ecozone II, the reservoir was cooler, as suggested by the increase of arctic-alpine taxa. The absence of Baikal Pliocene endemics and the presence of local endemics in the Tunka core indicate that there was no geographical connection between the palaeolake of the Tunka Valley and Lake Baikal during the Pliocene.
34
Kefena, E., T. Dessie, J. L. Han, M. Y. Kurtu, S. Rosenbom e A. Beja-Pereira. "Morphological diversities and ecozones of Ethiopian horse populations". Animal Genetic Resources/Ressources génétiques animales/Recursos genéticos animales 50 (giugno 2012): 1–12. http://dx.doi.org/10.1017/s2078633612000021.
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Amiro, B. D., J. M. Chen e Jinjun Liu. "Net primary productivity following forest fire for Canadian ecoregions". Canadian Journal of Forest Research 30, n. 6 (1 giugno 2000): 939–47. http://dx.doi.org/10.1139/x00-025.
Testo completoAbstract (sommario):
Recent modelling results indicate that forest fires and other disturbances determine the magnitude of the Canadian forest carbon balance. The regeneration of post-fire vegetation is key to the recovery of net primary productivity (NPP) following fire. We geographically co-registered pixels classed using the Boreal Ecosystem Productivity Simulator, a process-based model with AVHRR (advanced very-high resolution radiometer) satellite estimates of leaf-area index and land cover type, with polygons from a recent database of large Canadian fires. NPP development with time since fire was derived for the first 15 years following the disturbance in the boreal and taiga ecozones. About 7 × 106 ha were analysed for over 500 fires occurring between 1980 and 1994. NPP increases linearly through this period, at rates that depend on ecoregion. A longer data set for the Boreal Plains ecozone of Alberta shows that NPP levels off at about 20-30 years and remains constant for 60 years. The NPP trajectories can be used as spatial averages to support models of forest carbon balance and succession through the most fire-prone regions of Canada.
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Hall-Atkinson, Cynthia, e Laurence C. Smith. "Delineation of delta ecozones using interferometric SAR phase coherence". Remote Sensing of Environment 78, n. 3 (dicembre 2001): 229–38. http://dx.doi.org/10.1016/s0034-4257(01)00221-8.
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JHA, Radhika, Amita KANAUJIA e Kaushalendra Kumar JHA. "Wintering habitat modelling for conservation of Eurasian vultures in northern India". Nova Geodesia 2, n. 1 (5 marzo 2022): 22. http://dx.doi.org/10.55779/ng2122.
Testo completoAbstract (sommario):
Eurasian Black Vulture (EBV) and Eurasian Griffon Vulture (EGV), while residents elsewhere, winter in Uttar Pradesh, India. Knowledge of the habitat and regulating factors is obligatory for protection and better management of these vultures. Therefore, different types of habitats were mapped using eight species distribution models. Presence records from field survey, published data and citizen science, and 23 bioenvironmental raster layers were the model inputs. Eighteen models were developed whose strength varied greatly. As per the performance indicators, GBM and GLM were found to be superior models for EGV. For EBV all models were acceptable. MARS, with good model strength, was rejected on the grounds of field verification. However, the Ensemble model, overall, was found the best. As per this model, good habitat was restricted mostly in the Tarai ecozone. The top two vital variables were NDVI, and bio13 for both the vultures. The most vital temperature variable for EGV was bio08 while bio09 for EBV. Tarai ecozone showed the largest expanse of suitable area for both the vultures followed by Vindhyan-Bundelkhand, Gangetic plains and Semi-arid ecozones. Among the two, EBV (49000 km2) had more suitable area than EGV (37000 km2). Agricultural areas were found to be largely unsuitable. As per land cover, good habitat was mostly confined in forests. For better management of these wintering vultures which need only roosting and foraging, it is proposed that destruction of forested habitat and decrease in foraging materials needed immediate attention and control.
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Burton, Philip J., Marc-André Parisien, Jeffrey A. Hicke, Ronald J. Hall e Jason T. Freeburn. "Large fires as agents of ecological diversity in the North American boreal forest". International Journal of Wildland Fire 17, n. 6 (2008): 754. http://dx.doi.org/10.1071/wf07149.
Testo completoAbstract (sommario):
The present study undertook a hierarchical analysis of the variability within and among some individual fire events in the boreal ecozones of Canada and Alaska. When stratified by ecozone, differences in the spatial and temporal distribution of wildfires were observed in the Canadian Large Fire Data Base that reflect climatic, terrain and land-use differences across the country. Remote-sensing data collected before and after boreal forest fires permitted a rigorous analysis of the variability in burn severity within individual fire events, and the identification of certain fire-prone and more fire-resistant land-cover types. The occurrence of fire skips or islands was related to the distribution of those cover types, resulting in proportionally more unburned area within the perimeter of a burn for larger fires. Differences in burn severity led to differences in post-burn vegetation response of tree, shrub and moss layers that can persist for decades or even centuries. As a result, there can be considerable variability in the survival, density and distribution of residual biota and organic materials. This variability creates a range of post-fire vegetation patterns and contributes much to the habitat diversity of boreal landscapes.
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Beierkuhnlein, Carl, e Jan-Christopher Fischer. "Global biomes and ecozones – Conceptual and spatial communalities and discrepancies". Erdkunde 75, n. 4 (8 dicembre 2021): 249–70. http://dx.doi.org/10.3112/erdkunde.2021.04.01.
Testo completoAbstract (sommario):
Various facets of global changes and related problems and challenges are asking for sound impact assessments and corresponding coping strategies. The human impact on nature is a major driver of biodiversity loss and restricted ecosystem functioning and services. Assessing such global changes is often done by using biomes as benchmarks. However, even if the wording and terminology seem common sense (‘tropical rain forest’, ‘steppe’, ‘boreal forest’) global biome units and maps deviate in many ways. This is well justified by their individual intention, expert opinions, disciplinary background, and methodology of creation. A closer look reveals linkages between spatial accordance and common origin in climate classifications and maps. Their original influence, however, is rarely evident. In consequence, it is difficult if not impossible for users to realize and understand differences in these global maps. Furthermore, it is difficult to accept the fact that there is no common standard for global biomes. Even more surprising is the fact that some approaches are uncritically taken for common sense and are perpetuated over decades. This study aims to review established global biome concepts. Regions that are consistently assigned to comparable types of biomes shall be detected and also regions where ambiguity exists. For this purpose, we shortly review the history of existing concepts and the generic relations between them. Biomes, ecozones and climate classifications are considered. We digitized the most prominent biome classifications. Spatial match and mismatch between concepts were analyzed globally. We detect areas of spatial agreement and regions with ambiguous classifications. A clustering approach including 287 individual biomes originating from 12 established global biome concepts and their classifications/units revealed 12 terrestrial biome clusters among which 8 can be assigned to terrestrial ecological units. One cluster on ice caps adds to this. And finally, 3 clusters represent rather transition zones (ecotones), high mountain plateaus or are of minor areal extent. The spatial arrangement of these emerging clusters is displayed on a global map. Additionally, regions of uncertainty related to class assignment were identified. Those primarily occur in the vicinity of mountainous regions. The findings of this study should be seen as a work in progress and as a basis for further optimization of global biome concepts.
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Hopkinson, Chris, e Laura Chasmer. "Testing LiDAR models of fractional cover across multiple forest ecozones". Remote Sensing of Environment 113, n. 1 (gennaio 2009): 275–88. http://dx.doi.org/10.1016/j.rse.2008.09.012.
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He, Yuhong, Xulin Guo, Paul Dixon e John F. Wilmshurst. "NDVI variation and its relation to climate in Canadian ecozones". Canadian Geographer / Le Géographe canadien 56, n. 4 (16 agosto 2012): 492–507. http://dx.doi.org/10.1111/j.1541-0064.2012.00441.x.
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Sunil Kumar, S., D. A. Evans, K. Muthulakshmi, T. DilipKumar, R. Heera Pillai, R. Radhakrishnan Nair e Francis Sunny. "Distribution of Aedes aegypti and Aedes albopictus in different eco zones of Thiruvananthapuram city with special reference to dengue viremia in humans". ENTOMON 43, n. 4 (31 dicembre 2018): 223–30. http://dx.doi.org/10.33307/entomon.v43i4.402.
Testo completoAbstract (sommario):
Mosquito index study of three ecologically different ecozones of the Thiruvananthapuram district, Kerala showed sharp difference on the proportionate distribution of Aedes aegypti and Aedes albopictus. Human dengue viremia (HDV) was very high in those ecozones where A.aegypti density was high and HDV was low where A.albopictus was high. In a coastal zone of Thiruvananthapuram city, A. aegypti was the most abundant vector and in a hilly, arid suburban zone, A.albopictus was the abundant vector. In the urban zone both species of mosquitoes showed equal distribution. Study on the circulating serotypes in the serum of HDV by Single step single tube Multiplex PCR showed all the four serotypes viz DENV1, DENV2, DENV3 and DENV4 in patients of Thiruvananthapuram city, which indicated the possibility of Dengue Shock Syndrome, unless there is efficient vector management. Among the four dengue serotypes, Type 1 was the most abundant virus. Abundance of microhabitats in Thiruvananthapuram city, which support A. aegypti may be the reason for high prevalence of dengue fever in the urban zone.
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Hammell, Gord. "Changes to the Population Status of Horned Grebes (Podiceps auritus) and Red-necked Grebes (Podiceps grisegena) in Southwestern Manitoba, Canada". Canadian Field-Naturalist 131, n. 4 (23 maggio 2018): 317–24. http://dx.doi.org/10.22621/cfn.v131i4.2069.
Testo completoAbstract (sommario):
Continental trend data for North America suggest that Horned Grebe (Podiceps auritus) breeding populations are declining and Red-necked Grebe (P. grisegena) populations are increasing. However, data reliability is low due to lack of survey routes in the northern boreal and taiga ecozones, areas encompassing much of the breeding range of both species. Locally in the southern Manitoba prairie ecozone, reliability of long-term trend data is also considered low and these data suggest that Horned Grebe populations are declining faster than the continental trend and that Red-necked Grebe populations are increasing rapidly. The lack of current quantitative information on population densities of these two species in southern Manitoba prompted me to compare 1970s historical data from two sites to recent data collected at the same locations in 2008–2016. I surveyed 42 (1970–1972) and 38 (2008–2016), and 144 (2009–2015) Class III-V wetlands at Erickson and Minnedosa, Manitoba, respectively. Historical Minnedosa data were available from previous field studies. At both locations, Horned Grebe breeding populations have fallen significantly, and Red-necked Grebe populations have risen significantly since the 1970s. The results of this study corroborate the Breeding Bird Survey’s trend data for Horned and Red-necked Grebes in southwestern Manitoba pothole habitat.
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Minns, Charles K., James E. Moore, Brian J. Shuter e Nicholas E. Mandrak. "A preliminary national analysis of some key characteristics of Canadian lakes". Canadian Journal of Fisheries and Aquatic Sciences 65, n. 8 (agosto 2008): 1763–78. http://dx.doi.org/10.1139/f08-110.
Testo completoAbstract (sommario):
Knowledge of Canada’s lakes is needed to manage environmental stresses. Lake inventory and lake feature databases were used to build a national impact assessment template and assess regional typology. There are ~910 400 lakes with area ≥ 0.1 km2(10 ha), 37% of the Earth’s total. Lake features (number of lakes by size class, maximum depth, mean–maximum depth ratio, Secchi depth, pH, and total dissolved solids) were modeled regionally by secondary watershed (SWS) using linear regression models. Lake trout ( Salvelinus namaycush ) occurrence was analyzed as a cofactor to highlight regional links between lake characteristics and aquatic biota. Significant (R2from 0.231 to 0.492) regional models were obtained using area or maximum depth, lake trout occurrence, and their cross products as covariates. Analyses of fitted SWS coefficients showed that ecozones were a better predictor of lake characteristics than primary watersheds. The national typology was consistent with previous regional assessments. The regional models were used to estimate the number, area, and volume of lake trout lakes by size class and ecozone. There are ~66 500 lake trout lakes covering ~3 510 000 km2primarily on Boreal and Taiga Shield areas. Regional lake resource models will enable national assessment of stresses such as climate change and invasive species.
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Amiro, B. D., K. A. Logan, B. M. Wotton, M. D. Flannigan, J. B. Todd, B. J. Stocks e D. L. Martell. "Fire weather index system components for large fires in the Canadian boreal forest". International Journal of Wildland Fire 13, n. 4 (2004): 391. http://dx.doi.org/10.1071/wf03066.
Testo completoAbstract (sommario):
Canadian Fire Weather Index (FWI) System components and head fire intensities were calculated for fires greater than 2 km2 in size for the boreal and taiga ecozones of Canada from 1959 to 1999. The highest noon-hour values were analysed that occurred during the first 21 days of each of 9333 fires. Depending on ecozone, the means of the FWI System parameters ranged from: fine fuel moisture code (FFMC), 90 to 92 (82 to 96 for individual fires); duff moisture code (DMC), 38 to 78 (10 to 140 for individual fires); drought code (DC), 210 to 372 (50 to 600 for individual fires); and fire weather index, 20 to 33 (5 to 60 for individual fires). Fine fuel moisture code decreased, DMC had a mid-season peak, and DC increased through the fire season. Mean head fire intensities ranged from 10 to 28 MW m−1 in the boreal spruce fuel type, showing that most large fires exhibit crown fire behaviour. Intensities of individual fires can exceed 60 MW m−1. Most FWI System parameters did not show trends over the 41-year period because of large inter-annual variability. A changing climate is expected to create future weather conditions more conducive to fire throughout much of Canada but clear changes have not yet occurred.
46
Castrignanò, Annamaria, Daniela De Benedetto, Giacoma Girone, Francesca Guastaferro e Donato Sollitto. "Characterization, Delineation and Visualization of Agro- Ecozones Using Multivariate Geographical Clustering". Italian Journal of Agronomy 5, n. 2 (30 giugno 2010): 121. http://dx.doi.org/10.4081/ija.2010.121.
Testo completo
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Schmid, Rudolf, J. Schultz, Inge Jordan e Derek Jordan. "The Ecozones of the World: The Ecological Divisions of the Geosphere". Taxon 44, n. 4 (novembre 1995): 666. http://dx.doi.org/10.2307/1223535.
Testo completo
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Nealis, V. G., I. DeMerchant, D. Langor, M. K. Noseworthy, G. Pohl, K. Porter, E. Shanks, R. Turnquist e V. Waring. "Historical occurrence of alien arthropods and pathogens on trees in Canada". Canadian Journal of Forest Research 46, n. 2 (febbraio 2016): 172–80. http://dx.doi.org/10.1139/cjfr-2015-0273.
Testo completoAbstract (sommario):
The Canadian Forest Invasive Alien Species (CanFIAS) database provides point records of alien arthropod (insects and mites) and pathogen (fungi) species found on trees in Canada extracted from more than 100 years of national surveys. Each record includes a species identification, location, year of observation, and host association and is linked electronically to its original source. More than 175 000 records of 329 alien arthropod species and 11 plant pathogens are available. Historical rates of detection, as indicated by first records, were greatest in the decades following the two world wars. The overall rate has been approximately three species per year since 1900. Richness of alien species is greatest in the Coastal and Great Lakes–St. Lawrence forest ecozones and lowest in the Subalpine and Tundra ecozones. The alien species most significant in terms of extent of invasion and damage to trees are tree-host specialists, feeding on or infecting mostly one or two genera in a single plant family. Important commercial trees including pine, spruce, poplar, and birch and amenity genera including willow, cherry, and maple host the greatest diversity of alien species. Sap-feeding insects are the most speciose feeding group, but foliage-feeding and wood-boring insects and plant pathogens cause the most damage.
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de Roos, Baukje, Nanna Roos, Abdullah-Al Mamun, Tahmeed Ahmed, Alan A. Sneddon, Francis Murray, Eleonor Grieve e David C. Little. "Linking agroecosystems producing farmed seafood with food security and health status to better address the nutritional challenges in Bangladesh". Public Health Nutrition 22, n. 16 (5 settembre 2019): 2941–49. http://dx.doi.org/10.1017/s1368980019002295.
Testo completoAbstract (sommario):
AbstractObjective:Aquaculture is one of the fastest-growing food production sectors in many low-income and food-deficit countries with aquatic ecozones. Yet its specific impact on nutrition and livelihood in local communities, where commercial and/or export-orientated aquaculture activities are developed, is largely unknown.Design:The present narrative and argumentative review aims to provide an overview of our current understanding of the connections between aquaculture agroecosystems, local and national fish production, fish consumption patterns and nutrition and health outcomes.Results:The agroecological dynamic in a coastal-estuarine zone, where the aquatic environment ranges from fully saline to freshwater, is complex, with seasonal and annual fluctuations in freshwater supply creating a variable salinity gradient which impacts on aquatic food production and on food production more generally. The local communities living in these dynamic aquatic ecozones are vulnerable to poverty, poor diet and health, while these ecosystems produce highly valuable and nutritious aquatic foods. Policies addressing the specific challenges of risk management of these communities are limited by the sectoral separation of aquatic food production – the fisheries and aquaculture sector, the broader food sector – and public health institutions.Conclusions:Here we provide an argument for the integration of these factors to improve aquaculture value chains to better address the nutritional challenges in Bangladesh.
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Hansen, Matthew C., Peter V. Potapov, Amy H. Pickens, Alexandra Tyukavina, Andres Hernandez-Serna, Viviana Zalles, Svetlana Turubanova et al. "Global land use extent and dispersion within natural land cover using Landsat data". Environmental Research Letters 17, n. 3 (1 marzo 2022): 034050. http://dx.doi.org/10.1088/1748-9326/ac46ec.
Testo completoAbstract (sommario):
Abstract The conversion of natural land cover into human-dominated land use systems has significant impacts on the environment. Global mapping and monitoring of human-dominated land use extent via satellites provides an empirical basis for assessing land use pressures. Here, we present a novel 2019 global land cover, land use, and ecozone map derived from Landsat satellite imagery and topographical data using derived image feature spaces and algorithms suited per theme. From the map, we estimate the spatial extent and dispersion of land use disaggregated by climate domain and ecozone, where dispersion is the mean distance of land use to all land within a subregion. We find that percent of area under land use and distance to land use follow a power law that depicts an increasingly random spatial distribution of land use as it extends across lands of comparable development potential. For highly developed climate/ecozones, such as temperate and sub-tropical terra firma vegetation on low slopes, area under land use is contiguous and remnant natural land cover have low areal extent and high fragmentation. The tropics generally have the greatest potential for land use expansion, particularly in South America. An exception is Asian humid tropical terra firma vegetated lowland, which has land use intensities comparable to that of temperate breadbaskets such as the United States’ corn belt. Wetland extent is inversely proportional to land use extent within climate domains, indicating historical wetland loss for temperate, sub-tropical, and dry tropical biomes. Results highlight the need for planning efforts to preserve natural systems and associated ecosystem services. The demonstrated methods will be implemented operationally in quantifying global land change, enabling a monitoring framework for systematic assessments of the appropriation and restoration of natural land cover.