scholarly journals Disentangling the relative importance of spatio-temporal parameters and host selectivity in shaping AMF communities in temperate forests

2021 ◽  
Author(s):  
Leonie Grünfeld ◽  
Magkdi Mola ◽  
Monika Wulf ◽  
Stefan Hempel ◽  
Stavros D Veresoglou

AbstractMany woody and herbaceous plants in temperate forests cannot establish and survive in the absence of mycorrhizal associations. Here, we address and hierarchize how Glomeromycota, a group of soil-borne fungi, forming a ubiquitous type of mycorrhiza, varied in a temperate forest patch in Germany with time, space, plant hosts but also the proximity to Glomeromycota-associating woody species. The communities of Glomeromycota in our study were non-random. We observed that space had a greater impact on fungal community structure than either time or proximity to Glomeromycota-associating trees but unlike host identity did not alter Glomeromycotan richness. The set of parameters which we addressed has rarely been studied together and we believe that the resulting ranking could ease prioritizing some of them to include in future surveys. Glomeromycota are crucial for the establishment of understory plants in temperate forests making it desirable to further explore how they vary in time and space.

Mycorrhiza ◽  
2021 ◽  
Author(s):  
Leonie Grünfeld ◽  
Magkdi Mola ◽  
Monika Wulf ◽  
Stefan Hempel ◽  
Stavros D. Veresoglou

AbstractMany woody and herbaceous plants in temperate forests cannot establish and survive in the absence of mycorrhizal associations. Most temperate forests are dominated by ectomycorrhizal woody plant species, which implies that the carrying capacity of the habitat for arbuscular mycorrhizal fungi (AMF) is relatively low and AMF could in some cases experience a limitation of propagules. Here we address how the AMF community composition varied in a small temperate forest site in Germany in relation to time, space, two plant host species, and also with regard to the degree to which plots were covered with AMF-associating woody species. The AMF communities in our study were non-random. We observed that space had a greater impact on fungal community composition than either time, mycorrhizal state of the close-by woody species, or the identity of the host plant. The identity of the host plant was the only parameter that modified AMF richness in the roots. The set of parameters which we addressed has rarely been studied together, and the resulting ranking could ease prioritizing some of them to be included in future surveys. AMF are crucial for the establishment of understory plants in temperate forests, making it desirable to further explore how they vary in time and space.


2021 ◽  
Vol 11 (11) ◽  
pp. 5297
Author(s):  
Stavros D. Veresoglou ◽  
Leonie Grünfeld ◽  
Magkdi Mola

The roots of most plants host diverse assemblages of arbuscular mycorrhizal fungi (AMF), which benefit the plant hosts in diverse ways. Even though we understand that such AMF assemblages are non-random, we do not fully appreciate whether and how environmental settings can make them more or less predictable in time and space. Here we present results from three controlled experiments, where we manipulated two environmental parameters, habitat connectance and habitat quality, to address the degree to which plant roots in archipelagos of high connectivity and invariable habitats are colonized with (i) less diverse and (ii) easier to predict AMF assemblages. We observed no differences in diversity across our manipulations. We show, however, that mixing habitats and varying connectivity render AMF assemblages less predictable, which we could only detect within and not between our experimental units. We also demonstrate that none of our manipulations favoured any specific AMF taxa. We present here evidence that the community structure of AMF is less responsive to spatio-temporal manipulations than root colonization rates which is a facet of the symbiosis which we currently poorly understand.


2012 ◽  
Vol 5 (1) ◽  
pp. 16-23 ◽  
Author(s):  
J.C. González-Cortés ◽  
M. Vega-Fraga ◽  
L. Varela-Fregoso ◽  
M. Martínez-Trujillo ◽  
Y. Carreón-Abud ◽  
...  

2016 ◽  
Author(s):  
J. Joiner ◽  
Y. Yoshida ◽  
L. Guanter ◽  
E. M. Middleton

Abstract. Global satellite measurements of solar-induced fluorescence (SIF) from chlorophyll over land and ocean have proven useful for a number of different applications related to physiology, phenology, and productivity of plants and phytoplankton. Terrestrial chlorophyll fluorescence is emitted throughout the red and far-red spectrum, producing two broad peaks near 683 and 736 nm. From ocean surfaces, phytoplankton fluorescence emissions are entirely from the red region. Studies using satellite-derived SIF over land have focused almost exclusively on measurements in the far- red, since those are the most easily obtained with existing instrumentation. Here, we examine new ways to use existing hyper-spectral satellite data sets to retrieve red SIF over both land and ocean. Our approach offers noise reductions as compared with previously published solar line filling retrievals by making use of the oxygen (O2) γ-band that is not affected by SIF. The O2 γ-band in conjunction with solar Fraunhofer lines help to anchor the O2 B-band that provides additional information on red SIF. Biases due to instrumental artifacts that vary in time, space, and with instrument, must be addressed in order to obtain reasonable results. The satellite instruments that we use were designed to make atmospheric trace- gas measurements and are therefore not optimal for observing SIF; they have coarse spatial resolution and only moderate spectral resolution (∼0.5 nm). Nevertheless, these instruments offer a unique opportunity to compare red and far-red terrestrial SIF at regional spatial scales. Our eight year record of red SIF observations over land with the Global Ozone Monitoring Instrument 2 (GOME-2) allows for the first time reliable global mapping of monthly anomalies. These anomalies are shown to have similar spatio-temporal structure as those in the far-red, particularly for drought-prone regions. There is a somewhat larger percentage response in the red as compared with the far-red for these areas that are sensitive to soil moisture, although the differences are within the specified uncertainties that are dominated by systematic errors. We also demonstrate that high quality ocean fluorescence line height retrievals can be achieved with GOME-2 and similar instruments by utilizing the full complement of radiance measurements that span the red SIF emission feature.


Author(s):  
J. W. Li ◽  
Y. Ma ◽  
J. W. Jiang ◽  
W. D. Chen ◽  
N. Yu ◽  
...  

Abstract. Starting from the object-oriented idea, this paper analyses the existing event-based models and the logical relationship between behavioral cognition and events, and discusses the continuity of behavioral cognition on the time axis from the perspective of temporal and spatial cognition. A geospatial data model based on behavioral-event is proposed. The physical structure and logical structure of the model are mainly designed, and the four-dimensional model of “time, space, attribute and event” is constructed on the axis. The organic combination of the four models can well describe the internal mechanism and rules of geographical objects. The expression of data model based on behavior-event not only elaborates the basic information of geospatial objects, but also records the changes of related events caused by the changes of geographic Entities' behavior, and expresses the relationship between spatial and temporal objects before and after the changes of behavior cognition. This paper also designs an effective method to organize spatio-temporal data, so as to realize the effective management and analysis of spatio-temporal data and meet the requirements of storage, processing and mining of large spatio-temporal data.


2015 ◽  
Vol 7 (6) ◽  
pp. 1196
Author(s):  
Tiago Henrique de Oliveira ◽  
José Gleidson Dantas ◽  
Josiclêda Domiciano Galvíncio ◽  
Rejane Magalhães de Mendonça Pimentel ◽  
Milton Botler

As rápidas mudanças do uso e cobertura do solo em ambiente urbano apresentam grande impacto nas relações entre os ciclos energéticos e hidrológicos sobre a superfície. O município do Recife, através da Lei de Uso e Ocupação do Solo de 1996 (Lei nº 16.176/96) define área verde como “toda área de domínio público ou privado, em solo natural,onde predomina qualquer forma de vegetação, distribuída em seus diferentes estratos: Arbóreo, Arbustivo e Herbáceo /Forrageira, nativa ou exótica”. O objetivo deste artigo é analisar a variação espacial das áreas verdes disponíveis no município do Recife e a evolução espaço-temporal da qualidade ambiental na RPA 4 através do computo do Índice de umidade (NDWI), Índice de Área Foliar (IAF) e Temperatura da superfície em imagens TM Landsat. Foi realizada uma classificação supervisionada na ortofotocarta Recife onde as áreas verdes foram exportadas para polígonos, permitindo a sua quantificação. Para as imagens TM foi aplicada parte da metodologia SEBAL. As áreas verdes ocupam 45,58% do Recife. Os transectos lineares e perfis permitiram visualizar mais facilmente as mudanças espaço-temporais ocorridos na RPA-4. Foi visualizada grande diferença de temperatura entre as áreas vegetadas e as áreas mais urbanizadas. Palavras-chave: Uso e ocupação do solo; área urbana, áreas vegetadas, sensoriamento remoto; MAXVER. A B S T R A C T The rapid change of use and land cover in urban environment poses great impact on relations between energy and hydrological cycles on the surface. The municipality of Recife, through the Land Use Legislation from 1996 (Law No. 16.176/96) defines green area as ";;;;;;any public or private domain area, in natural soil, where overcrows any form of vegetation, distributed in its different layers: Arboreal, shrubby and Herbaceous Forage, native or exotic";;;;;;. The goal of this paper is to analyze the spatial variation of available green areas in the city of Recife and the spatio-temporal evolution of environmental quality in the Political Administrative Region 4, known as RPA-4, through the calculation of moisture content (NDWI), leaf area index (LAI) and the surface temperature from Landsat TM images. Supervised classification was performed on orthophoto Reef where the green areas were exported to polygons, allowing its quantification. For the TM images, it has been applied the methodology SEBAL. The green areas occupy 45.58% of Recife. The linear transects and profiles allowed to show more easily space-time changes occurring in the RPA-4. Large temperature differences have been displayed between the most vegetated areas and more urbanized areas. Key-words: Land use; urban areas; vegetated area, remote sensing; MAXVER.


2021 ◽  
Vol 44 (2) ◽  
pp. 87-111
Author(s):  
Nicholas A. Eckstein

Michel Foucault argued famously that early modern European governors responded to plague by quarantining entire urban populations and placing citizens under minute surveillance. For Foucault, such sixteenth- and seventeenth-century policies were the first steps towards an authoritarian paradigm that would only emerge in full in the eighteenth century. The present article argues that Foucault’s model is too abstracted to function as a tool for the historical examination of specific emergencies, and it proposes an alternative analytical framework. Addressing itself to actual events in early modern Italy, the article reveals that when plague threatened, Florentine and Bolognese health officials projected themselves into a spatio-temporal dimension in which official actions and perceptions were determined solely by the spread of contagion. This dimension, “plague time,” was not a stage on the irresistible journey towards Foucault’s “utopia of the perfectly governed city.” A contingent response to a recurrent existential menace, plague time rose and fell in response to events, and may be understood as a season.


Author(s):  
Nikos C. Apostolopoulos

On the basis of their corporeity humans are not only beings of distance but also the beings of proximity, rooted beings, not only inner worldly but also beings in the world (Patocka, 1998)Over the centuries the dialectical confluence of metaphysics and epistemology has been at the forefront in the attempt to define the concept of what it is to be human and ultimately human existence. The union of several aspects conceived from these two opposite elements has been responsible for the genesis of numerous philosophical terms and ideas such as: rationalism, materialism, socialism and idealism. Although these terms reference something different, what is primarily at the core has been the endeavour to analyse and demonstrate that it is through man’s relationship with nature that one garners the understanding of self. Human consciousness in conjunction with a spatio-temporal perception, defined as movement through the time-space continuum, creates the condition where the possibility of defining the essence of existence may blossom. In this commentary, an effort is made to present movement, specifically its relationship to the “body” as the physical construct for the meaning of self.


2011 ◽  
Vol 31 (4) ◽  
pp. 652-662
Author(s):  
Jorge C. dos A. Antonini ◽  
Euzebio M. da Silva ◽  
Nori P. Griebeler ◽  
Edson E. Sano

The objective of this work was to develop and validate a mathematical model to estimate the duration of cotton (Gossypium hirsutum L. r. latifolium hutch) cycle in the State of Goiás, Brazil, by applying the method of growing degree-days (GD), and considering, simultaneously, its time-space variation. The model was developed as a linear combination of elevation, latitude, longitude, and Fourier series of time variation. The model parameters were adjusted by using multiple-linear regression to the observed GD accumulated with air temperature in the range of 15°C to 40°C. The minimum and maximum temperature records used to calculate the GD were obtained from 21 meteorological stations, considering data varying from 8 to 20 years of observation. The coefficient of determination, resulting from the comparison between the estimated and calculated GD along the year was 0.84. Model validation was done by comparing estimated and measured crop cycle in the period from cotton germination to the stage when 90 percent of bolls were opened in commercial crop fields. Comparative results showed that the model performed very well, as indicated by the Pearson correlation coefficient of 0.90 and Willmott agreement index of 0.94, resulting in a performance index of 0.85.


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