scholarly journals Spatial distribution of invasive species: an extent of occurrence approach

Test ◽  
2021 ◽  
Author(s):  
Alberto Rodríguez-Casal ◽  
Paula Saavedra-Nieves
Keyword(s):  
Invasive Species ◽  
Invasive Plant ◽  
Temporal Distribution ◽  
Regularity Conditions ◽  
Stochastic Algorithm ◽  
Extent Of Occurrence ◽  
Geometric Assumption ◽  
Spatio Temporal ◽  
Support Estimation ◽  
The Impact

AbstractEcological Risk Assessment faces the challenge of determining the impact of invasive species on biodiversity conservation. Although many statistical methods have emerged in recent years in order to model the evolution of the spatio-temporal distribution of invasive species, the notion of extent of occurrence, formally defined by the International Union for the Conservation of Nature, has not been properly handled. In this work, a novel and flexible reconstruction of the extent of occurrence from occurrence data will be established from nonparametric support estimation theory. Mathematically, given a random sample of points from some unknown distribution, we establish a new data-driven method for estimating its probability support S in general dimension. Under the mild geometric assumption that S is $$r-$$ r - convex, the smallest $$r-$$ r - convex set which contains the sample points is the natural estimator. A stochastic algorithm is proposed for determining an optimal estimate of r from the data under regularity conditions on the density function. The performance of this estimator is studied by reconstructing the extent of occurrence of an assemblage of invasive plant species in the Azores archipelago.

scholarly journals On the Effect of Red Sea and Topography on Rainfall over Saudi Arabia: Case Study

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 669
Author(s):  
Al-Mutairi ◽  
Abdel Basset ◽  
Morsy ◽  
Abdeldym
Keyword(s):  
Saudi Arabia ◽  
Red Sea ◽  
Sea Water ◽  
Wrf Model ◽  
Temporal Distribution ◽  
Surface Fluxes ◽  
Sensitivity Experiment ◽  
Low Level ◽  
Spatio Temporal ◽  
The Impact

This paper aimed to investigate the impact of Red Sea topography and water on the development and rainfall of a case of cyclogenesis occurs over Saudi Arabia during the period 16–18 November 2015 using the Weather Research and Forecasting (WRF) model. The WRF Control Run (WRF-CR) experiment was performed with presence of actual topography and surface water of the Red Sea, while the other three sensitivity experiments were carried out without (i) Red Sea Topography (NRST), (ii) Red Sea Water (NRSW), and (iii) Red Sea Topography and Water (NRSTW). The simulated rainfall in the control experiment depicts in well agreement with Tropical Rainfall Measurement Mission (TRMM) rainfall estimates in terms of intensity as well as spatio-temporal distribution. Results demonstrate that rainfall intensity and spatio-temporal distribution significantly changes through each sensitivity experiment compared to the WRF-CR, where the significant variation was found in the NRST experiment. The absence of topography (NRST) leads to formation of strong convergence area over the middle of Red Sea which enhanced uplift motion that further strengthened the low-level jet over Red Sea and the surrounding regions, which enhanced the moisture and temperature gradient and created a conditionally unstable atmosphere that favored the development of the cyclonic system. The absence of Red Sea water (NRSW) changed rainfall spatial distribution and reduced its amount by about 30–40% due to affecting of the dynamics of the upward motion and moisture gradient, suggesting that surface fluxes play an important role in regulating the low-level moist air convergence prior to convection initiation and development.

Effect of Periodic Voluntary Interventions on Trapezius Activation and Fatigue During Light Upper Limb Activity

2021 ◽  
pp. 001872082110507
Author(s):  
Dongwon Kim ◽  
Corine Nicoletti ◽  
Subaryani D. H. Soedirdjo ◽  
Raziyeh Baghi ◽  
Maria-Gabriela Garcia ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Muscle Activation ◽  
Temporal Distribution ◽  
Trapezius Muscle ◽  
Computer Work ◽  
3 Dimensional ◽  
Intervention Activity ◽  
Spatio Temporal ◽  
Voluntary Contractions ◽  
The Impact

Objective The effects of diverse periodic interventions on trapezius muscle fatigue and activity during a full day of computer work were investigated. Background Musculoskeletal disorders, including trapezius myalgia, may be associated with repeated exposure to prolonged low-level activity, even during light upper-extremity tasks including computer work. Methods Thirty healthy adults participated in a study that simulated two 6-hour workdays of computer work. One workday involved imposed periodic passive and active interventions aimed at disrupting trapezius contraction monotony (Intervention day), whereas the other workday did not (Control day). Trapezius muscle activity was quantified by the 3-dimensional acceleration of the jolt movement of the acromion produced by electrically induced muscle twitches. The spatio-temporal distribution of trapezius activity was measured through high-density surface electromyography (HD-EMG). Results The twitch acceleration magnitude in one direction was significantly different across measurement periods ( p = 0.0156) on Control day, whereas no significant differences in any direction were observed ( p > 0.05) on Intervention day. The HD-EMG from Intervention day showed that only significant voluntary muscle contractions (swing arms, Jacobson maneuver) induced a decrease in the muscle activation time and an increase in the spatial muscle activation areas ( p < 0.01). Conclusion Disruption of trapezius monotonous activity via brief voluntary contractions effectively modified the ensuing contraction pattern (twitch acceleration along one axis, active epochs reduction, and larger spatial distribution). The observed changes support an associated reduction of muscle fatigue. Application This study suggests that disruptive intervention activity is efficient in reducing the impact of trapezius muscle fatigue.

scholarly journals The impact of multiple species invasion on soil and plant communities increases with invader diversity

2021 ◽  
Author(s):  
Dusanka Vujanovic ◽  
Gianalberto Losapio ◽  
Stanko Milic ◽  
Dubravka Milic
Keyword(s):  
Invasive Species ◽  
Invasive Plants ◽  
Plant Diversity ◽  
Invasive Plant ◽  
Single Species ◽  
Soil Conditions ◽  
Native Plant ◽  
Multiple Invasions ◽  
Native Plant Diversity ◽  
The Impact

Despite increasing evidence indicating that invasive species are harming ecological systems and processes, impacts of multiple invasions, and the linkages between these events and changes in vegetation and soil are inadequately documented and remain poorly understood. Addressing multiple invasions would help to highlight high priority invaders and would aid in designing more effective control strategies, contributing to environmental restoration and sustainability. In this work, we tested the impact of three concurring invasive plant species, Amorpha fruticosa, Fraxinus pennsylvanica and Acer negundo, on soil conditions and native plant diversity. The research was conducted in riparian ecosystem and included the following treatments: (1) co-occurrence of the three invasive plant species, (2) occurrence of a single invasive species, and (3) control, i.e., absence of invasive species. Our findings revealed that the impact of invasive plants on soil properties and native plant diversity is magnified by their co-occurrence. Soil in mixed plots (those populated with all three invaders) contained much higher levels of nitrifying bacteria (NB), organic matter (Om), nitrogen (N), and carbon (C) as well as lower carbon to nitrogen ratio (C:N) levels, compared to single species invaded plots and control plots. Mixed plots were also characterized by reduced native plant diversity compared to single species invaded and control plots. Differences in soil conditions and native plant diversity revealed the interactive potential of invasive plants in depleting biodiversity, and thus in affecting ecological and biogeochemical processes. Our results highlight the need to study the impact of multispecies invasion and suggest that sites in riparian areas affected by co-occurring invaders, should be prioritized for ecosystem restoration. Keywords: Acer negundo, Amorpha fruticosa, Fraxinus pennsylvanica, invasive plants, multiple invasions, soil properties

scholarly journals Invasive species in the soil seed bank of two limestone hills in Bogor, West Java, Indonesia

2021 ◽  
Vol 22 (9) ◽  
Author(s):  
Winda Utami Putri ◽  
Ibnul Qayim ◽  
Abdul Qadir
Keyword(s):  
Invasive Species ◽  
Seed Bank ◽  
Invasive Plant ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Extraction Methods ◽  
Specific Information ◽  
West Java ◽  
Soil Seed Banks ◽  
The Impact

Abstract. Putri WU, Qayim I, Qadir A. 2021. Invasive species in the soil seed bank of two limestone hills in Bogor, West Java, Indonesia. Biodiversitas 22: 4019-4027. Study on the impact of invasive species on plant communities has been conducted mainly on the aboveground vegetation. The impact on the soil seed bank has received less attention mostly due to practical difficulties in conducting seed bank assessment. Evaluation of seed bank composition is useful in detecting invasive plant species that may have been present as buried seeds. Information on the vegetation composition in Nyungcung and Kapur hills both under and aboveground is available, but specific information on invasive species has not been discussed yet. This paper describes and analyzes the structure (composition and density) of invasive species in the soil seed bank. Eighty soil samples were taken from the study sites. The soil seed banks were analyzed using seedling emergence and seed extraction methods. 2602 and 1280 seedlings emerged from soil seed bank of Nyungcung and Kapur hills, respectively. From that number, approximately 48.96% and 68.51% of the seedlings are invasive species in the soil seed bank of Nyungcung and Kapur hills. The invasive species were dominants in the soil seed bank of the two sites. Cecropia peltata and Clidemia hirta were the most abundant invasive species in the Kapur and Nyungcung hills seed bank, respectively. Species richness and seedling density were higher in Nyungcung hills than Kapur hills, which were invaded for a relatively longer period.

Snow Cover Dynamics and its Spatio-Temporal Distribution in the Central Higher Himalaya of India

2021 ◽  
Vol 14 (9) ◽  
pp. 15-22
Author(s):  
Masoom Reza ◽  
Ramesh Chandra Joshi
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Geographical Area ◽  
Temporal Distribution ◽  
Melting Rate ◽  
Optical Data ◽  
Snow Cover Area ◽  
Central Himalayas ◽  
Spatio Temporal ◽  
The Impact

Retreating glaciers, changing timber line and decreasing accumulation of snow in the Himalaya are considered the indicators of climate change. In this study, an attempt is made to observe the snow cover change in the higher reaches of the Central Himalayas. Investigation of climate change through snow cover is very important to understand the impact and adaptation in an area. Landsat thematic and multi spectral optical data with a spatial resolution of 60m and 30m are considered for the estimation and extraction of snow cover. Total 3,369 Km2 snow cover area is lost since 1972 out of total geographical area i.e. 17,227 Km2. The accumulation of snow during winter is lower than the melting rate during summer. The current study identified the decrease of 19.6 % snow cover in 47 years since 1972 to 2019. Composite satellite imageries of September to December show that the major part of the study area covered with snow lies above 3600m. Overall observation indicates that in 47 years, permanent snow cover is decreasing in Central Himalayas.

scholarly journals Invazivne biljke kalničkih šuma

2016 ◽  
Vol 140 (1-2) ◽  
pp. 64-64
Author(s):  
Gabrijel Horvat ◽  
Jozo Franjić
Keyword(s):  
Invasive Species ◽  
Plant Species ◽  
Tree Species ◽  
Invasive Plant ◽  
Ambrosia Artemisiifolia ◽  
Invasive Plant Species ◽  
Important Species ◽  
Forest Lands ◽  
The Impact ◽  
Acacia Tree

This paper presents an invasive plant species that occur in the forests of Kalnik. It also presents the state of the distribution and their impact on forests of Kalnik. A total of 14 invasive species in the forests of Kalnik and these are – Acer negundo L., Ailanthus altissima (Mill.) Swingle, Ambrosia artemisiifolia L., Amorpha fruticosa L., Asclepias syriaca L., Conyza canadensis (L.) Cronquist, Echinocystis lobata (Michx.) Torr. et Gray, Erigeron annuus (L.) Pers., Impatiens glandulifera Royle, Juncus tenuis Willd.), Phytolacca americana L., Reynoutria japonica Houtt., Robinia pseudoacacia L., Solidago gigantea Aiton. Alochtonous vegetation is not only inevitable, but it also appears to be a constant future challenge in the globalizing world which communicates on all levels with every means possible. Its influence should not by any means be marginalized. Its importance and influence is not completely negative and there are possible benefits and dangers which should be controlled by the preventive measures and physical regulation. The most important species in Kalnik forest vegetation is definitely acacia. It is especially important for private forest lands where acacia tree has become very popular because of its characteristics as a fast growing tree species without any special requirements with relation to growth and it gives fast results concerning timber and firewood. Private lots are usually very small and fragmented. There is a growing need for timber, therefore the trees are grown extensively, from stumps and roots. Other woody species still do not pose a serious threat in economical or biological sense. The impact of herbaceous plants differs in various areas. The most problematic issues for the forestersare thick layers of unwanted specieswhich grow in young forest stands or in forests in the phase of restorationwhere these unwanted speciesinvasively compete with autochthonous species. In biological sense, invasive species pose a constant threat not only to domestic vegetation and biodiversity, but also to human health. We should also mention apiculture, a very important and well developed activity on Kalnik. Above mentioned species are very important and interesting for apiculture as a type of rich bee pasturage. Apiculture in this area depends on acacia pasturage and it is one of very important reasons for growing acacia tree. Other tree species are also valuable for bee pasturage, especially late in autumn when there is no other bee pasturage available and they are mostly species which blossom in autumn and represent a valuable source of pollen (Japanese Knotweed, Prickly cucumber and European goldenrod). Generally speaking, the biggest responsibility for possible consequences of invasive plant species to the vegetation of Kalnik lies on foresters who have to recognize and monitor the appearance of invasive species, especially in state forest lands where they grow and directly influence their composition and state.

scholarly journals Moisture recycling over the Iberian Peninsula. The impact of 3DVAR data assimilation

2020 ◽  
Author(s):  
Santos J. González-Rojí ◽  
Jon Sáenz ◽  
Javier Díaz de Argandoña ◽  
Gabriel Ibarra-Berastegi
Keyword(s):  
Soil Moisture ◽  
Data Assimilation ◽  
Iberian Peninsula ◽  
Wrf Model ◽  
Temporal Distribution ◽  
Horizontal Resolution ◽  
Moisture Recycling ◽  
Weather Observations ◽  
Spatio Temporal ◽  
The Impact

&lt;p&gt;The moisture recycling is defined as the fraction of precipitation over a delimited region that comes from the evaporation over that region. Its importance lies in the fact that it is an approximated measurement of a regional feedback between the atmosphere and the surface. Thus, this study estimates the spatio-temporal distribution of moisture recycling over the Iberian Peninsula (IP), and focuses on the impact of the use of 3DVAR data assimilation during the modeling stage.&lt;/p&gt;&lt;p&gt;For that purpose, two different simulations were run using the Weather and Research Forecasting (WRF) model with a horizontal resolution of 15 km over the IP. The first simulation (WRF N) was nested inside ERA-Interim as usual in numerical downscaling exercises, with information passed to the domain through the boundaries. The second run (WRF D) presents the same configuration as WRF N, but it also includes 3DVAR data assimilation step every six hours (at 00, 06, 12 and 18 UTC). Sea surface temperature was updated daily, and observations in PREPBUFR format included in the NCEP ADP Global Upper Air and Surface Weather Observations dataset were used for the data assimilation step. Only those inside a 120-minute window centered at the analysis times were assimilated. Both simulations cover the period 2010-2014, but the experiment WRF D was extended later until 2018.&lt;/p&gt;&lt;p&gt;The lowest values of moisture recycling (around 3 %) are obtained from November to February, while the most remarkable values are observed in spring (around 16 %) in both simulations. The moisture recycling is confined to the southeastern corner of the IP during winter. However, during spring and summer, a gradient of higher values towards the northeastern corner of the IP are observed in both simulations. The differences between simulations, associated to the dryness of the soil in the model, are highlighted during summer and autumn. WRF D presents a lower bias and produces more reliable results because of a better representation of the atmospheric moisture.&lt;/p&gt;&lt;p&gt;A Cross-Correlation Function (CCF) based analysis was performed for each combination of moisture recycling, accumulated precipitation and mean soil moisture over the IP. For the common period (2010-2014), the results show that the WRF D experiment extends the lifespan of moisture over the IP. The CCF analysis for soil moisture against precipitation also shows an unphysical negative lag (-1 month) for WRF N, whilst for WRF D both variables are simultaneous. For the extended WRF D simulation (2010-2018), it was found that the delay between precipitation and moisture recycling over the IP is five months.&lt;/p&gt;

scholarly journals Spatio-Temporal Characteristics of SO2 across Weifang from 2008 to 2020

2021 ◽  
Vol 18 (22) ◽  
pp. 12206
Author(s):  
Lining Zhu ◽  
Yu Zhang ◽  
Zheng Wu ◽  
Chengcheng Zhang
Keyword(s):  
Wind Direction ◽  
Quantitative Research ◽  
Pollution Prevention ◽  
Temporal Distribution ◽  
Research Area ◽  
Small Scale ◽  
Macro Scale ◽  
Spatio Temporal ◽  
The Impact ◽  
So2 Pollution

China has achieved good results in SO2 pollution control, but SO2 pollution still exists in some areas. Analyzing the spatio-temporal distribution of SO2 is critical for regional SO2 pollution prevention and control. Compared with existing air pollution studies that paid more attention to PM2.5, NO2 and O3, and focused on the macro scale, this study took the small-scale Weifang city as the research area, analyzed the temporal and spatial changes in SO2, discussed the migration trajectory of SO2 pollution and explored the impact of wind on SO2 pollution. The results show that the average annual concentration of SO2 in Weifang has exhibited a downward trend in the past 13 years, showing the basic characteristics of “highest in winter, lowest in summer and slightly higher in spring and autumn”, “highest on Sunday, lowest on Thursday and gradually decreasing from Monday to Thursday” and “highest at 9 a.m., lowest at 4 p.m. and gradually increasing from midnight to 9 a.m.”. SO2 concentration showed obvious spatial heterogeneity: higher in the north and lower in the south. In addition, Shouguang, Changyi and Gaomi were seriously polluted. The SO2 pollution shifted from south to northeast. The clean wind direction (southeast wind and northeast wind) of Weifang city accounted for about 41%, and the pollution wind direction (northwest wind and west wind) accounted for about 7%. Drawing from the multi-scale analysis, vegetation, precipitation, temperature, transport situation and human activity were the most relevant factors. Limited to data collection, more quantitative research is needed to gain insight into the influence mechanism in the future.

scholarly journals Environmental indicators combined with risk analysis to evaluate potential wildfire incidence on the Dadu Plateau in Taiwan

2021 ◽  
Author(s):  
Chao-Yuan Lin ◽  
Pei-Ying Shieh ◽  
Shao-Wei Wu ◽  
Po-Cheng Wang ◽  
Yung-Chau Chen
Keyword(s):  
Risk Analysis ◽  
Risk Model ◽  
Fire Severity ◽  
Temporal Distribution ◽  
Environmental Indicators ◽  
Coefficient Of Determination ◽  
Temporal And Spatial Distribution ◽  
Ecological Disturbance ◽  
Spatio Temporal ◽  
The Impact

Abstract Wildfire is a common disaster in the world, and it has a considerable impact on the safety of residents and ecological disturbance. Periodic wildfires are an urgent problem to be solved. This research uses big data from relevant departments to extract environmental indicators that affect wildfires, including satellite images, meteorological observations, and field surveys and establishes a risk model for the Spatio-temporal distribution of wildfires based on risk analysis. Previous studies using Differenced Normalized Burn Ratio (dNBR) to assess fire severity and distinguish wildfire ruins did not deal with the impact of atmospheric humidity on dNBR values. In this study, an adjustable fire threshold was developed to enable dNBR to improve the accuracy of identifying wildfire locations. Regarding the temporal distribution of wildfire risks, environmental vulnerability cannot specifically reflect the frequency of actual wildfires. If the hazard degree is introduced to calculate the wildfire risk, the coefficient of determination can be increased from 0.49 to 0.79. The verification of the village boundary zone depicts that the risk analysis can effectively show the temporal and spatial distribution of wildfire hotspots. On this basis, a village-level wildfire disaster prevention strategy can be formulated.

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