Search results for "Life on Land"
showing 10 items of 1478 documents
Sampling strategy in molecular microbial ecology: influence of soil sample size on DNA fingerprinting analysis of fungal and bacterial communities.
2003
Assessing soil microbial community structure by the use of molecular techniques requires a satisfactory sampling strategy that takes into account the high microbial diversity and the heterogeneous distribution of microorganisms in the soil matrix. The influence of the sample size of three different soil types (sand, silt and clay soils) on the DNA yield and analysis of bacterial and fungal community structure were investigated. Six sample sizes from 0.125 g to 4 g were evaluated. The genetic community structure was assessed by automated ribosomal intergenic spacer analysis (A-RISA fingerprint). Variations between bacterial (B-ARISA) and fungal (F-ARISA) community structure were quantified b…
Dependence of accelerated degradation of atrazine on soil pH in French and Canadian soils
2000
Abstract A series of agricultural soils varying in their atrazine treatment history were sampled from 12 sites in France and two sites in Canada. The soils varied widely with respect to soil chemical, physical and microbiological (total microbial biomass, kinetics of C and N mineralization) properties. Soils treated with as few as two successive atrazine field applications mineralized [U- ring - 14 C]atrazine significantly more rapidly in 35 d laboratory incubations than did soils which had never received atrazine. Longer treatment history tended to favour more rapid mineralization in the so-called “adapted” soils. Up to 80% of the initially applied 14 C-atrazine was mineralized at the end …
Effects of distance and scale dependence in geographical models of cities and territories
2019
International audience; This third chapter questions the essential role of distance and scale dependence in models to analyzing the spatial configuration of human settlements and activities, as well as the processes that lead to their evolution, with reference to urban or regional study areas. The subject of study therefore concerns both the form of human settlements and the actions of people (individuals, groups) in their territory (or territories). A human settlement consists of the materialization in space-the physical inscription-of one or more human activities. It is characterized by a certain degree of sustainability. It can be a group of a few buildings or a larger group of thousands…
Morphological vs. molecular delineation of taxa across montane regions in Europe: the case study of Gammarus balcanicus Schäferna, (Crustacea: Amphip…
2014
Mountainous areas are characterized by substantial biodiversity and endemicity due to their complex geological history and habitat fragmentation. Hence, it can be assumed that particularly high species richness can be found in organisms with limited dispersal capabilities that inhabit mountain streams. A number of scientific papers focus on molecular phylogeography or traditional taxonomy of species or species groups inhabiting such habitats. However, there is a lack of studies that integrate morphological and molecular data to identify and delineate cryptic species. For practical reasons, uncovering cryptic diversity is crucial in taxa used in biomonitoring. Distinct species, hard to separ…
Nonlinear Complex PCA for spatio-temporal analysis of global soil moisture
2020
Soil moisture (SM) is a key state variable of the hydrological cycle, needed to monitor the effects of a changing climate on natural resources. Soil moisture is highly variable in space and time, presenting seasonalities, anomalies and long-term trends, but also, and important nonlinear behaviours. Here, we introduce a novel fast and nonlinear complex PCA method to analyze the spatio-temporal patterns of the Earth's surface SM. We use global SM estimates acquired during the period 2010-2017 by ESA's SMOS mission. Our approach unveils both time and space modes, trends and periodicities unlike standard PCA decompositions. Results show the distribution of the total SM variance among its differ…
Modeling Forest Tree Data Using Sequential Spatial Point Processes
2021
AbstractThe spatial structure of a forest stand is typically modeled by spatial point process models. Motivated by aerial forest inventories and forest dynamics in general, we propose a sequential spatial approach for modeling forest data. Such an approach is better justified than a static point process model in describing the long-term dependence among the spatial location of trees in a forest and the locations of detected trees in aerial forest inventories. Tree size can be used as a surrogate for the unknown tree age when determining the order in which trees have emerged or are observed on an aerial image. Sequential spatial point processes differ from spatial point processes in that the…
Effects of elevated ozone on physiological, anatomical and ultrastructural characteristics of four common urban tree species in China
2016
Fast urbanization has led to ozone (O3) being the main pollutant in summer in most of China. To assess future ground-level O3 effects on the service of urban greening species and clarify the underlying mechanism of O3 damage, four common urban greening species, Ailanthus altissima (AA), Fraxinus chinensis(FC), Platanus orientalis (PO) and Robinia pseudoacacia (RP) were exposed to non-filtered air (NF) and to elevated O3 (E-O3) in open-top chambers. E-O3 induced visible injury in all species as well as microscopic alterations such as collapse of the palisade parenchyma cells, callose accumulation, or chloroplast and mitochondrial accelerated senescence. E-O3 significantly reduced light-satur…
Equity in REDD+: Varying logics in Tanzania
2015
Equity is frequently cited as one of the key design aspects of environmental governance regimes. In the context of Reduced Emissions from Deforestation and Forest Degradation (REDD+), a forest-based climate change mitigation instrument, the manner in which ‘equity’ is understood will be of critical importance for the impacts and acceptance of REDD + policies and initiatives. Whereas the concept has been extensively studied in the academic literature, references to equity in REDD + policy debates and documents are often vague, leaving room for various interpretations and modes of implementation. In our case study of the Tanzanian national REDD + policy domain, we provide a conceptual framewo…
Barriers and Bridges for Landscape Stewardship and Knowledge Production to Sustain Functional Green Infrastructures
2018
Sustainable landscapes and regions require both stewardship and management to sustain the composition, structure and function of ecosystems as a base for delivering human benefits. This complex is captured by the topic of ecosystem services. To deliver these, the concept green (or blue) infrastructure emerged as a tool for spatial planning of networks of natural and semi-natural areas. Such planning requires evidence-based knowledge about both ecological and social systems. For ecosystems, states and trends need be monitored, and improved knowledge must be developed about ecological tipping points for assessment of sustainability, as well as measures for conservation, management and restora…
Names for trace fossils: a uniform approach.
2006
The taxonomic treatment of trace fossils needs a uniform approach, independent of the ethologic groups concerned. To this aim, trace fossils are rigorously defined with regard to biological taxa and physical sedimentary structures. Potential ichnotaxobases are evaluated, with morphology resulting as the most important criterion. For trace fossils related to bioerosion and herbivory, substrate plays a key role, as well as composition for coprolites. Size, producer, age, facies and preservation are rejected as ichnotaxobases. Separate names for undertracks and other poorly preserved material should gradually be replaced by ichnotaxa based on well-preserved specimens. Recent traces may be iden…