disturbed condition
Recently Published Documents


TOTAL DOCUMENTS

27
(FIVE YEARS 5)

H-INDEX

6
(FIVE YEARS 1)

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 676
Author(s):  
Hannah Cave ◽  
Matthew Adams ◽  
Tristan Jaeger ◽  
Taylor Peet ◽  
Lloyd Staats ◽  
...  

Natural disturbances are an integral part of forested ecosystem function and successional pathways. In many forested ecosystems, wildfires are critical to shaping composition and structure, which, in turn, has major implications for wildlife usage and behavior. In July 2018, a wildfire burned 225 ha of the Altona Flat Rock pine barrens in northern New York. This event presented the opportunity to study how wildlife respond to the immediate effects of disturbance in this unique habitat but also how that response would change through time as regeneration progressed. Game cameras were deployed from September 2018 to September 2020 at two reference (unburned) and two disturbed (burned) sites within the pine barrens. We analyzed total and seasonal occurrences, to determine how usage differed between disturbed and reference conditions, and with time since disturbance. Additionally, for coyote (Canis latrans, Say), white-tailed deer (Odocoileus virginianus, Zimmermann), and snowshoe hare (Lepus americanus, Erxleben), we evaluated daily activity patterns and overlap to determine how predator–prey relationships differed between conditions, and with time since disturbance. Over 730 days, a total of 1048 wildlife occurrences were captured across 23 wildlife species. Fifty-seven percent of all occurrences were at reference sites with over 100 more occurrences than at disturbed sites; however, differences were most pronounced immediately following the fire and overall occurrences have grown more similar between the sites over time. Specifically, deer and hare were found more often at reference sites immediately following the fire, but shifted to using both conditions equally by the first growing season. Habitat overlap among sympatric prey (deer, hare) can be explained by understory regeneration increasing foraging opportunities and concealment cover in the disturbed condition, while predators (coyotes) tracked prey availability regardless of the habitat condition. This study provides wildlife management guidance on habitat use and response to disturbance for these unique sandstone pavement barrens.


2021 ◽  
Author(s):  
Débora Toledo Ramos ◽  
Henry Xavier Corseuil ◽  
Timothy M. Vogel

ABSTRACTWorldwide efforts to depollute environments altered by human industrial activity have begun to produce an ever-increasing number of “clean” sites. “Clean” is defined by local regulatory processes and often responds to low compound concentrations or risk evaluations. Yet, these sites have been critically derailed from their historical biological activity by both the pollution event and the clean-up technology. This work explored the impact of contaminated (and remediated) sites on local microbial ecosystems. Different parcels of the same field site with the same relatively uniform microbial ecology were polluted and cleaned-up over the last 15 years. The statistical evaluation of the perturbation described changes to the local ecosystem that went back to the original baseline microbial composition although the pollution sources and the clean-up technologies affected the rate of return to the pre-disturbed condition. This rate reflected the intensity of the clean-up treatments. The role played by microbial communities on ecosystem maintenance and mitigation of pollution events lays the groundwork for predicting the microbial community responses to perturbations and the ability to reassert themselves. Predictions of ecosystem response to anthropogenic impacts could support decision-making on environmental management strategies for contaminated sites clean-up, depending on the ecosystem services desired to maintain or the risk posed to sensitive receptors.


2020 ◽  
Author(s):  
Chao-Yen Chen ◽  
Jann-Yenq Liu

<p>This paper investigates the plasmapause positions in the ionosphere by measurement of the whistler count probed by DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite in the daytime at 1030 LT (local time) and the nighttime at 2230 LT during 2005-2010.  The whistler finds the plasmapause position which can be clearly allocated in both daytime and nighttime.  We examine the nighttime/daytime plasmapause in various longitudes, solar activities, seasons, and geomagnetic actives.  Results show that the daytime plasmapause appears in the equatorward side of the nighttime one.  Both the daytime and nighttime plasmapause are sensitive to solar activity, which move equatorward form the low to high solar activity in the study period.  The seasonal variation of the plasmapause are rather random and insignificant.  During magnetic disturbed condition, the plasmapause tend to move equatorward.</p>


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 703 ◽  
Author(s):  
Yiannis Panagopoulos ◽  
Kostas Stefanidis ◽  
Marta Faneca Sanchez ◽  
Frederiek Sperna Weiland ◽  
Rens Van Beek ◽  
...  

The hydrologic regime of a river is one of the factors determining its ecological status. This paper tries to indicate the present hydrologic stress occurring across European rivers on the basis of model integration. This results in a pan-European assessment at the resolution of the functional elementary catchment (FEC), based on simulated daily time-series of river flows from the model PCR-GLOBWB. To estimate proxies of the present hydrologic stress, two datasets of river flow were simulated under the same climate, one from a hypothetic least disturbed condition scenario and the second from the anthropogenic scenario with the actual water management occurring. Indicators describing the rivers’ hydrologic regime were calculated with the indicators of hydrologic alteration (IHA) software package and the river total mean flow and the relative baseflow magnitude over the total flow were used to express the deviations between the two scenarios as proxy metrics of rivers’ hydrologic alteration or hydrologic stress. The alteration results on Europe’s FEC-level background showed that Southern Europe is more hydrologically stressed than the rest of Europe, with greater potential for hydrology to be clearly associated with river segments of unreached good ecological status and high basin management needs.


Transport ◽  
2018 ◽  
Vol 33 (3) ◽  
pp. 853-860
Author(s):  
Nicola BONGIORNO ◽  
Gaetano BOSURGI ◽  
Orazio PELLEGRINO ◽  
Giuseppe SOLLAZZO

This paper analyses the driver’ visual behaviour in the different conditions of ‘isolated vehicle’ and ‘disturbed vehicle’. If the meaning of the former is clear, the latter condition considers the influence on the driving behaviour of various objects that could be encountered along the road. These can be classified in static (signage, stationary vehicles at the roadside, etc.) and dynamic objects (cars, motorcycles, bicycles). The aim of this paper is to propose a proper analysis regarding the driver’s visual behaviour. In particular, the authors examined the quality of the visually informa-tion acquired from the entire road environment, useful for detecting any critical safety condition. In order to guaran-tee a deep examination of the various possible behaviours, the authors combined the several test outcomes with other variables related to the road geometry and with the dynamic variables involved while driving. The results of this study are very interesting. As expected, they obviously confirmed better performances for the ‘isolated vehicle’ in a rural two-lane road with different traffic flows. Moreover, analysing the various scenarios in the disturbed condition, the proposed indices allow the authors to quantitatively describe the different influence on the visual field and effects on the visual behaviour, favouring critical analysis of the road characteristics. Potential applications of these results may contribute to improve the choice of the best maintenance strategies for a road, to select the optimal signage location, to define forecasting models for the driving behaviour and to develop useful instruments for intelligent transportation systems.


2018 ◽  
Vol 4 (2) ◽  
pp. 67-79
Author(s):  
Remon Muslim ◽  
Ferry Fatnanta ◽  
Muhardi M

Peat has different characteristics compared to clay. It is physically recognized as soil with organic materials content, great amount of water, high void ratio, and the existence of fibers. However, it technically has high compressibility and low shear strength. To identify how big is the influence of compression behaviour towards the increment of peat`s shear strength, some consolidation and vane shear test need to be performed in order to obtain a proper method to initiate constructions on peat. This research used amorphous peat samples which were taken from Tambang, Kampar district in disturbed condition. They consisted of two variations, i.e.: natural condition, and non-fiber condition. The used equipments were modified consolidometer with diameter of 15 cm and height of 15 cm, and also vane shear instruments. The loads were gradually applied with magnitude of 10 kPa, 20 kPa, 40 kPa, 80 kPa, 160 kPa and 320 kPa, each of them were elevated every ±14 days, and a vane shear test was performed before the load was added. The results showed that the shear strength has been increasing due to the higher compression, as well as the void ratio. In case the void ratio gets smaller, the shear strength has increased. Hence, peat`s bearing capacity will increase along with the higher shear strength.


2018 ◽  
Vol 53 (4) ◽  
pp. 231-240
Author(s):  
C. L. Proulx ◽  
B. W. Kilgour ◽  
A. P. Francis ◽  
R. F. Bouwhuis ◽  
J. R. Hill

Abstract The underlying natural relationship between conductivity and alkalinity was used to identify surface water quality monitoring sites that are in a ‘reference’ or minimally disturbed condition. Data from over 40,500 freshwater samples from 1,230 sites were combined for the time period of 2005–2015 from various federal, provincial, and joint federal–provincial/territorial freshwater monitoring programs (e.g., Freshwater Quality Monitoring and Surveillance Program, Ontario's Provincial Water Quality Monitoring Network). Of the samples, 30,347 provided conductivity and alkalinity data. Surface water samples with a measured conductivity that deviated (by more than 41 μS/cm) from the predicted conductivity calculated from the sample's alkalinity were deemed to be non-representative of a reference condition, while samples within 41 μS/cm of the predicted value were deemed representative of a reference condition. The 41 μS/cm cutoff value was determined using signal detection theory. The conductivity–alkalinity model was validated through a comparison with land cover data by demonstrating that samples identified as ‘reference’ were typically from catchments that had minimal anthropogenic disturbances. The proposed approach provides a rapid means of evaluating the reference condition of a watercourse, and of identifying data that provide an estimate of reference condition.


2018 ◽  
Vol 26 (1) ◽  
pp. 46-51 ◽  
Author(s):  
L. I. Faly ◽  
V. V. Brygadyrenko

The litter invertebrate community consists of species from different size, trophic and taxonomic groups. The distribution of the animal population of the litter horizon depends upon many factors, especially the content of the phytocoenosis, the projective herbaceous plant cover, moisture, litter thickness and the soil texture. This article analyses the variability of the main characteristics of litter invertebrate communities (total number, number of species, diversity according to the Shannon–Wiener and Pielou indices) on plots with different herbaceous plant composition and cover in plantations of Robinia pseudoacacia L. in the South steppe zone of Ukraine (territory of the “Tiligulsky” Regional Landscape Park). The taxonomic structure of the litter communities in the Robinia plantation was dominated by predatory groups of invertebrates (Carabidae, Aranea, Formicidae). The abundance of Julidae, Isopoda, Silphidae and Staphylinidae was relatively low. The studied forest plots were characterized by the simplified size structure of the litter macrofauna. The absence of species with body length of 16–20 mm and length over 20 mm indicates damage to the most significant trophic chains. The forest belt studied is in a highly disturbed condition, the plots being dominated by steppe species of herbaceous plants. The analyzed factors (diversity and extent of cover of herbaceous plants) do not determine the structure of the litter macrofauna community but affect it indirectly: a slight increase in the total number of invertebrates was observed in areas with minimal and maximum number of species of herbaceous plants. The relationship between the abundance of invertebrates and the percentage of herbaceous plant cover is manifested insignificantly. We noted a tendency for the number of invertebrate species to decrease along the gradient of herbaceous plant cover due to the concentration of dominant predatory species which exterminate other trophic groups of macrofauna.


2017 ◽  
Vol 18 (2) ◽  
pp. 229 ◽  
Author(s):  
I. MELERO ◽  
S. LÓPEZ-VELASCO ◽  
E. LÓPEZ

During the summer of 2014, a field survey was conducted in several littoral rocky sites on the southeastern coast of Spain. In this area, dense canopies of Cystoseira mediterranea characterize undisturbed locations and cover most of the available infralittoral fringe. Turfs composed mainly of the coralline algae Ellisolandia elongata replace the canopy in locations where some kind of anthropogenic disturbance has occurred. The main goal of this study was to compare the polychaete fauna dwelling within the two types of phytal substratum, and several univariate and multivariate analyses were performed to detect significant differences between the two assemblages. The analyses showed that the assemblage inhabiting E. elongata was characterized by a higher population density of polychaetes and was dominated by herbivores and filter-feeders, especially Fabricia stellaris and Amphiglena mediterranea. Polychaetes were less abundant in pristine sites covered by Cystoseira mediterranea, although a-diversity was slightly higher. This assemblage was characterized by a predominance of omnivores followed by herbivores, and by high relative abundances of Syllis prolifera and Salvatoria clavata. However, none of the detected differences was statistically significant and site to site comparison showed that differences between locations with the same phytal cover were similarly deep. Our data point out that the assemblage inhabiting turf algae in the region studied is not substantially different to that found in pristine areas and that this type of phytal covering can act as effective refuge for polychaetes under moderately disturbed condition.  


Sign in / Sign up

Export Citation Format

Share Document