Spatial distribution of volcanic ash deposits of 2011 Puyehue-Cordón Caulle eruption in Patagonia as measured by a perturbation in NDVI temporal dynamics

2018 ◽  
Vol 353 ◽  
pp. 11-17 ◽  
Author(s):  
M.H. Easdale ◽  
O. Bruzzone
Keyword(s):  
Spatial Distribution ◽  
Volcanic Ash ◽  
Temporal Dynamics

scholarly journals Spatial distribution and temporal variation of microcrustaceans assembly (Cladocera and Copepoda) in different compartments of a reservoir in the brazilian semiarid region

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Josiane Souza Santos ◽  
Nadson Ressyé Simões ◽  
Sérgio Luiz Sonoda
Keyword(s):  
Spatial Distribution ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Aquatic Macrophytes ◽  
Temporal Dynamics ◽  
Lateral Compartment ◽  
Spatial And Temporal Variation ◽  
Semiarid Region ◽  
Brazilian Semiarid ◽  
Significant Spatial Variation

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.

Spatial variation in soil physical properties and effects on soil NO3– production on forest hillslopes

2020 ◽  
Author(s):  
Tomoki Oda ◽  
Megumi Kuroiwa ◽  
Naoya Fujime ◽  
Kazuo Isobe ◽  
Naoya Masaoka ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Physical Properties ◽  
Spatial Variation ◽  
Volcanic Ash ◽  
Surface Soil ◽  
Soil Physical Properties ◽  
Slope Position ◽  
Surface Soil Moisture ◽  
Slope Bottom

<p>Ammonium (NH<sub>4</sub><sup>+</sup>) and nitrate (NO<sub>3</sub><sup>–</sup>) concentrations and production rates in forest soil vary by hillslope position due to variation in ammonia-oxidizing microorganism concentrations, soil chemistry, and surface soil moisture. These spatial distributions have a significant effect on nutrient cycles and streamwater chemistry. Soil moisture conditions significantly restrict microbial activity, influencing the spatial distribution of NO<sub>3</sub><sup>–</sup> concentrations on forest hillslopes. However, studies linking forest hydrological processes to nitrogen cycling are limited. Therefore, we investigated the determinants of spatial variation in soil moisture and evaluated the effects of soil moisture fluctuations on spatial variation in NO<sub>3</sub><sup>–</sup> concentration and production rate.</p><p>The study sites were the Fukuroyamasawa Experimental Watershed (FEW) and Oyasan Experimental Watershed (OEW) in Japan. The two have similar topographies, climates, and tree species. In each watershed, a 100 m transect was set up from the ridge to the base of the slope, and soil moisture sensors were installed at soil depths of 10 cm and 30 cm at both the top and bottom of the slope. We collected surface soil samples at a depth of 10 cm at the top, middle, and bottom of the slopes using 100 cm<sup>3</sup> cores, and measured soil physical properties, particle size distribution, volcanic ash content, chemical properties (pH, NO<sub>3</sub><sup>–</sup>, NH<sub>4</sub><sup>+</sup>, nitrification rate, and mineralization rate), and microbial content (archaeal content). Spatial and temporal changes in soil moisture on the hillslope were calculated using HYDRUS-2D to examine contributing factors of soil moisture.</p><p>At FEW, high NO<sub>3</sub><sup>–</sup> concentrations and nitrification rates were observed only at the slope bottom and middle, and no NO<sub>3</sub><sup>–</sup> concentrations were detected at up slope. By contrast, at OEW, high NO<sub>3</sub><sup>–</sup> concentrations and nitrification rates were observed at all points. NH<sub>4</sub><sup>+</sup> concentrations were similar at all points in both watersheds. At FEW, 10 cm surface soil moisture fluctuated within 25–40% at the slope top but was within 40–50% at the slope bottom. At OEW, surface soil moisture was 30–40% at both the slope top and bottom, with no significant differences according to slope position. It was confirmed that soil moisture was significantly involved in NO<sub>3</sub><sup>– </sup>concentration and nitrification rates. Model simulations showed that the difference in soil moisture fluctuations between FEW and OEW was mainly explained by the spatial variation in soil physical properties. In particular, volcanic ash influenced soil moisture along the entire slope at OEW, resulting in high water retention, but only influenced soil moisture at the slope bottom at FEW. These findings indicate that spatial variability in soil physical properties has a significant effect on soil moisture fluctuation and leads to a spatial distribution of NO<sub>3</sub><sup>–</sup> production.</p>

Spatial distribution and temporal dynamics of high-elevation forest stands in southern Siberia

2010 ◽  
Vol 19 (6) ◽  
pp. 822-830 ◽  
Author(s):  
Vyacheslav I. Kharuk ◽  
Kenneth J. Ranson ◽  
Sergey T. Im ◽  
Alexander S. Vdovin
Keyword(s):  
Spatial Distribution ◽  
Temporal Dynamics ◽  
High Elevation ◽  
Forest Stands ◽  
Southern Siberia ◽  
High Elevation Forest

Zooplankton in Advective Environments: The Hudson River Community and a Comparative Analysis

1992 ◽  
Vol 49 (5) ◽  
pp. 1060-1069 ◽  
Author(s):  
Michael L. Pace ◽  
Stuart E. G. Findlay ◽  
David Lints
Keyword(s):  
Spatial Distribution ◽  
Dominant Species ◽  
Temporal Dynamics ◽  
Hudson River ◽  
Zooplankton Biomass ◽  
Spatial Distributions ◽  
Water Residence Time ◽  
Advective Transport ◽  
Lotic Environments ◽  
Planktonic Communities

The temporal dynamics and spatial distributions of zooplankton in the tidal freshwater portion of the Hudson River were studied over a 3-yr period. We tested the hypothesis that advective transport regulates zooplankton biomass in the Hudson and in lakes, estuaries, and rivers for which we have published values. In the Hudson, zooplankton biomass was negatively correlated with discharge over the entire season (P < 0.0001) as well as during the warmer period of the year (P = 0.007) when biomass was greatest. The spatial distribution of zooplankton over 160-km transects was heterogeneous. Downstream changes in the abundance of a dominant species, Bosmina longirostris, indicate that certain areas of the river support net population growth whereas other areas are population sinks. We infer that zooplankton biomass in the Hudson is a function of the balance between reproduction determined by resources and losses due to advection. Zooplankton biomass differs among lakes, estuaries, and rivers in a manner consistent with the differences in water residence time. Biomass is highest in lakes, lower in saline estuaries and tidal rivers, and lowest in rivers. Advective losses appear to be important in explaining differences between planktonic communities in lentic and lotic environments.

scholarly journals Human influence on the temporal dynamics and spatial distribution of forest biomass carbon in China

2017 ◽  
Vol 7 (16) ◽  
pp. 6220-6230 ◽  
Author(s):  
Weiwei Liu ◽  
Fei Lu ◽  
Yunjian Luo ◽  
Wenjing Bo ◽  
Lingqiao Kong ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Temporal Dynamics ◽  
Forest Biomass ◽  
Biomass Carbon ◽  
Human Influence

scholarly journals Aedes albopictus bionomics data collection by citizen participation on Procida Island, a promising Mediterranean site for the assessment of innovative and community-based integrated pest management methods

2021 ◽  
Vol 15 (9) ◽  
pp. e0009698
Author(s):  
Beniamino Caputo ◽  
Giuliano Langella ◽  
Valeria Petrella ◽  
Chiara Virgillito ◽  
Mattia Manica ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Citizen Participation ◽  
Aedes Albopictus ◽  
Temporal Dynamics ◽  
Mosquito Control ◽  
Vector Competence ◽  
Temporal Distribution ◽  
Effective Control ◽  
Gulf Of Naples ◽  
New Public Health

In the last decades, the colonization of Mediterranean Europe and of other temperate regions by Aedes albopictus created an unprecedented nuisance problem in highly infested areas and new public health threats due to the vector competence of the species. The Sterile Insect Technique (SIT) and the Incompatible Insect Technique (IIT) are insecticide-free mosquito-control methods, relying on mass release of irradiated/manipulated males, able to complement existing and only partially effective control tools. The validation of these approaches in the field requires appropriate experimental settings, possibly isolated to avoid mosquito immigration from other infested areas, and preliminary ecological and entomological data. We carried out a 4-year study in the island of Procida (Gulf of Naples, Italy) in strict collaboration with local administrators and citizens to estimate the temporal dynamics, spatial distribution, and population size of Ae. albopictus and the dispersal and survival of irradiated males. We applied ovitrap monitoring, geo-spatial analyses, mark-release-recapture technique, and a citizen-science approach. Results allow to predict the seasonal (from April to October, with peaks of 928–9,757 males/ha) and spatial distribution of the species, highlighting the capacity of Ae. albopictus population of Procida to colonize and maintain high frequencies in urban as well as in sylvatic inhabited environments. Irradiated males shown limited ability to disperse (mean daily distance travelled <60m) and daily survival estimates ranging between 0.80 and 0.95. Overall, the ecological characteristics of the island, the acquired knowledge on Ae. albopictus spatial and temporal distribution, the high human and Ae. albopictus densities and the positive attitude of the resident population in being active parts in innovative mosquito control projects provide the ground for evidence-based planning of the interventions and for the assessment of their effectiveness. In addition, the results highlight the value of creating synergies between research groups, local administrators, and citizens for affordable monitoring (and, in the future, control) of mosquito populations.

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