scholarly journals Variation in hip and sepal parameters of invasive Rosa rugosa between sites and years

Botanica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Zigmantas Gudžinskas ◽  
Mindaugas Rasimavičius
Keyword(s):  
Invasive Species ◽  
Environmental Factors ◽  
Sunshine Duration ◽  
Negative Relationship ◽  
Cumulative Effect ◽  
Field Studies ◽  
Width Ratio ◽  
Coastal Habitat ◽  
Rosa Rugosa ◽  
Sepal Length

Rosa rugosa is among the most invasive species in Europe, and it is considered a severe threat to the diversity and stability of coastal habitats. In Lithuania, it is a widespread invasive species occurring in coastal and inland areas. This research aimed to estimate the variation in R. rugosa hip and sepal parameters within and among sites from coastal and inland areas, and investigate the effects of environmental factors on the hip and sepal sizes. Field studies were performed at four coastal and three inland sites in 2008, and the studies were repeated in 2016. We collected 100 mature hips at each site and measured the hip width, hip length and sepal length. We analysed variation in hip and sepal parameters between the study years, and the effect of meteorological factors and agrochemical properties of the soil on hip and sepal sizes. This study revealed significant variation in R. rugosa hip width, hip length and sepal length among the studied sites. The largest hips and sepals were found in the coastal habitat at the Smeltė site, whereas the smallest hips and sepals were recorded in inland habitat at the Staviškės site, where R. rugosa occurred in woodland. The comparison of hip and sepal sizes at the same sites during two study years revealed irregular variation. Mean hip width and mean length of sepals in 2008 were significantly more prominent than in 2016, whereas no significant differences in hip length were found between the study years. The content of phosphorus in the soil negatively correlated, whereas the content of carbonates positively correlated with the sepal length. A strong negative relationship was found between the sunshine duration and hip length and width ratio. However, the revealed relationships of the hip and sepal parameters with the environmental factors could be a coincidence or a result of the cumulative effect of the multiple factors’ interaction and should be investigated separately.

Didymosphenia geminata in two Alberta headwater rivers: an emerging invasive species that challenges conventional views on algal bloom development

2007 ◽  
Vol 64 (12) ◽  
pp. 1703-1709 ◽  
Author(s):  
Andrea E Kirkwood ◽  
Troina Shea ◽  
Leland J Jackson ◽  
Edward McCauley
Keyword(s):  
Invasive Species ◽  
Environmental Factors ◽  
Flow Regime ◽  
Negative Relationship ◽  
Invasion Biology ◽  
Water Clarity ◽  
Supporting Evidence ◽  
Mean Flow ◽  
Didymosphenia Geminata ◽  
New Variant

The diatom Didymosphenia geminata (Bacillariophyceae) has garnered increased attention as a nuisance and invasive species in freshwater systems. Historically described as rare yet cosmopolitan, a suspected new variant of D. geminata has the capacity to inundate kilometres of river bottom during a bloom. Unlike most other bloom-forming algae, D. geminata proliferates under high water quality (i.e., low turbidity and low nutrient) conditions. To inform management strategies, the environmental factors and conditions that promote bloom events must be ascertained. Our study of the Bow and Red Deer rivers in southern Alberta, Canada, provides supporting evidence that the mean flow regime is associated with bloom development, based on a significant negative relationship detected between D. geminata biomass and mean discharge (r2 = 0.30). While flow regulation by dams can create the stable flow environment preferred by D. geminata, our results indicate that flow regime (rather than just proximity to dam outflows) is the likely mechanism, in addition to other environmental factors, such as water clarity, temperature, pH, conductivity, and total phosphorus. We discuss the formidable challenges to D. geminata management, particularly along unregulated river reaches, yet also recognize the unique research opportunities that this organism poses for the growing field of invasion biology.

Collectivistic Leadership in Context: An Examination of How and When Collective Charismatic Leadership Relates to Unit Functioning

2021 ◽  
pp. 154805182098653
Author(s):  
Jonathan C. Ziegert ◽  
David M. Mayer ◽  
Ronald F. Piccolo ◽  
Katrina A. Graham
Keyword(s):  
Social Inclusion ◽  
Task Complexity ◽  
Contextual Factors ◽  
Negative Relationship ◽  
Field Studies ◽  
Charismatic Leadership ◽  
Interactive Effects ◽  
Collective Leadership ◽  
Contingency Perspective ◽  
The Impact

This research explores the nature of collective leadership by examining the boundary conditions of how and when it relates to unit functioning. Building from a contingency perspective that considers the impact of contextual factors, we propose that collective charismatic leadership will be associated with lowered unit conflict, and this relationship will be strengthened by the contingency elements of individual charismatic leadership, task complexity, and social inclusion. Furthermore, we propose that the interactions of collective charismatic leadership with these contextual factors will relate to performance and satisfaction through conflict. We examine our hypotheses across two unit-level field studies, and the results illustrated that high levels of these contextual factors enhanced the negative relationship between collective charismatic leadership and conflict, which generally mediated the relationships between these interactive effects and performance and satisfaction. The results also highlight the detrimental aspects of collective leadership and how it can relate to reduced unit functioning when it is not aligned with an appropriate context. Overall, these findings begin to provide a more complete picture of collective leadership from a contingency perspective through a greater understanding of when and how it is related to unit functioning.

Seeds and seasons: interpreting germination timing in the field

2005 ◽  
Vol 15 (3) ◽  
pp. 175-187 ◽  
Author(s):  
Kathleen Donohue
Keyword(s):  
Environmental Factors ◽  
Genetic Basis ◽  
Genetic Material ◽  
Field Studies ◽  
Seed Maturation ◽  
Genetic Pathways ◽  
Ecological Conditions ◽  
Germination Phenology ◽  
Transgenic Lines ◽  
Germination Timing

This paper discusses how field and laboratory experiments, using a variety of genetic material, can be combined to investigate the genetic basis of germination under realistic ecological conditions, and it reviews some of our recent work on germination phenology ofArabidopsis thalianain the field. Our results indicate that the genetic basis of germination depends on the environment. In particular, the conditions during seed maturation interact with post-dispersal environmental factors to determine germination phenology, and these interactions have a genetic basis. Therefore genetic studies of germination need to consider carefully the environment – both during seed maturation and after dispersal – in which the experiments are conducted in order to characterize genetic pathways involved with germination in the field. Laboratory studies that explicitly manipulate ecologically relevant environmental factors can be combined with manipulative field studies. These studies can identify the particular environmental cues to which seeds respond in the field and characterize the genetic basis of germination responses to those cues. In addition, a variety of genetic material – including mutant and transgenic lines, intact natural genotypes, recombinant genotypes, and near isogenic lines – can be used in field studies as tools to characterize genetic pathways involved in germination schedules under natural ecological conditions.

scholarly journals Diseases and Pests of Ash-Leaved Maple (Acer negundo L.) in Moscow region

2018 ◽  
pp. 79-87
Author(s):  
O.I. Yasinskaya
Keyword(s):  
Invasive Species ◽  
Environmental Factors ◽  
Woody Plants ◽  
Moscow Region ◽  
Acer Negundo ◽  
Adventitious Species ◽  
Resistance To Diseases

In the megapolis, native and adventitious species of woody plants are exposed to the most powerful adverse environmental factors that reduce resistance to diseases and pests. The investigation objective was to identify diseases and pests of a dangerous invasive species Acer negundo L. and to estimate their effect on invasion activity of this species. A. negundo leaves are affected by Рhyllosticta negundinis (Sacc. et Speg.), Sawadaia bicornis (Wallr. ex. Fr.) Miyabe and are occasionally damaged by a timber pest such as Rhopalopus clavipes F. A set of unfavorable environmental factors cause noninfectious toxicosis of A. negundo leaves. Meanwhile, all these diseases and pests do not cause considerable harm to A negundo and do not substantially reduce its invasion activity.

scholarly journals Increased size and relative abundance of migratory fishes observed near the Athabasca oil sands

FACETS ◽  
2017 ◽  
Vol 2 (2) ◽  
pp. 833-858 ◽  
Author(s):  
Tim J. Arciszewski ◽  
Kelly R. Munkittrick ◽  
Bruce W. Kilgour ◽  
Heather M. Keith ◽  
Janice E. Linehan ◽  
...  
Keyword(s):  
Oil Sands ◽  
Cumulative Effect ◽  
Field Studies ◽  
White Sucker ◽  
Athabasca Oil Sands ◽  
Data Set ◽  
Arctic Grayling ◽  
Normal Ranges ◽  
The Status ◽  
Relative Abundances

Responses to chemical and physical stressors are commonly expected among organisms residing near the Athabasca oil sands. Physiological effects have been observed in fishes during field studies; but further effects associated with development are not clear or consistent among species. For instance, data from a fish fence in 2009 show declines in the relative abundances of some species, including Arctic grayling ( Thymallus arcticus). In contrast, increases were seen in white sucker ( Catostomus commersoni). This divergence suggests incomplete understanding of the status of fishes residing near the oil sands. However, an important challenge limiting understanding is the lack of reliable baseline or reference data. To overcome this challenge, we used iterative normal ranges and a historical data set (electrofishing surveys done from 1987 to 2014) to determine if changes have occurred in fishes captured in the lower Athabasca River. These analyses revealed clear increases in the lengths of white sucker and walleye ( Sander vitreus) and their relative abundances during the spawning season. The occurrence of these changes may be associated with overwintering location, but reduced fishing pressure in Lake Athabasca, eutrophication, or a cumulative effect may explain the form of changes detected in this study.

Coastal Habitat Restoration, Invasive Species and Remote Monitoring Solutions

2022 ◽  
pp. 160-176
Author(s):  
Sophie Walker ◽  
Nathan Waltham ◽  
Christina Buelow ◽  
Jordan Iles
Keyword(s):  
Invasive Species ◽  
Remote Monitoring ◽  
Habitat Restoration ◽  
Coastal Habitat

scholarly journals The ecology of shell shape difference in chirally dimorphic snails

2012 ◽  
Vol 81 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Menno Schilthuizen ◽  
Martin Haase ◽  
Kees Koops ◽  
Sylvia M. Looijestijn ◽  
Sigrid Hendrikse
Keyword(s):  
Sexual Selection ◽  
Environmental Factors ◽  
Field Studies ◽  
Southeast Asian ◽  
Predation Pressure ◽  
Shell Shape ◽  
Ecological Traits ◽  
Shape Difference ◽  
Environmental Selection

The Southeast-Asian tree snail subgenus Amphidromus s. str. (Gastropoda Pulmonata: Camaenidae) is unusual among all gastropods for its genetic antisymmetry: populations consist of stable mixtures of individuals with clockwise (dextral) and counterclockwise (sinistral) coiling directions. Although previous studies in A. inversus suggest that this genetic dimorphism is maintained by sexual selection, it cannot be ruled out that environmental factors also play a role. Adult shell shapes in A. inversus are known to show subtle differences between both coiling morphs, and it is known that in snails in general, shell shape is under environmental selection, thus creating the possibility that micro-niche use of both coiling morphs differs. In this paper, we first confirm that hatchlings also differ in shell shape. We then proceed with field studies to compare dextral and sinistral juveniles and adults for (i) direction and rate of dispersal within the vegetation and (ii) micro-niche occupation. However, we failed to detect any difference in both ecological traits. In addition to earlier data that show that there is no clustering of morphs in the field and that both morphs suffer identical predation pressure, these new data do not provide any evidence for a role for environmental factors in maintaining the coil dimorphism in this species.

Relating initial paraquat injury to final efficacy in selected weed species influenced by environmental conditions

2020 ◽  
pp. 1-10
Author(s):  
Nick T. Harre ◽  
Garth W. Duncan ◽  
Julie M. Young ◽  
Bryan G. Young
Keyword(s):  
Environmental Factors ◽  
Negative Relationship ◽  
Injury Rate ◽  
Time Of Day ◽  
Palmer Amaranth ◽  
Shoot Biomass ◽  
Lag Phase ◽  
Progression Rate ◽  
Weed Species ◽  
Time Of Application

Abstract Weed control of paraquat can be erratic and may be attributable to differing species sensitivity and/or environmental factors for which minor guidance is available on commercial labels. Therefore, the objectives of this research were to quantify selectivity of paraquat across select weed species and the influence of environmental factors. Experiments were performed under controlled conditions in the greenhouse and growth chamber. Compared with purple deadnettle (dose necessary to reduce shoot biomass by 50% = 39 g ai ha−1), waterhemp, Palmer amaranth, giant ragweed, and horseweed were 4.9, 3.3, 1.9, and 1.3 times more sensitive to paraquat, respectively. The injury progression rate over 3 d after treatment (DAT) was a more accurate predictor of final efficacy at 14 DAT than the lag phase until symptoms first appeared. For example, at the 17.5 g ha−1 dose, the injury rate of waterhemp and Palmer amaranth was, on average, 3.6 times greater than that of horseweed and purple deadnettle. The influence of various environmental factors on paraquat efficacy was weed specific. Applications made at sunrise improved control of purple deadnettle over applications at solar noon or sunset. Lower light intensities (200 or 600 μmol m−2 s−1) surrounding the time of application improved control of waterhemp and horseweed more than 1,000 μmol m−2 s−1. Day/night temperatures of 27/16 C improved horseweed and purple deadnettle control compared with day/night temperatures of 18/13 C. Though control was positively associated with injury rates in the application time of day and temperature experiments, a negative relationship was observed for waterhemp in the light-intensity experiment. Thus, although there are conditions that enhance paraquat efficacy, the specific target species must also be considered. These results advocate paraquat dose recommendations, currently based on weed height, be expanded to address sensitivity differences among weeds. Moreover, these findings contrast with paraquat labels stating temperatures of 13 C or lower do not reduce paraquat efficacy.

scholarly journals Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161380 ◽  
Author(s):  
Ryan P. Kovach ◽  
Brian K. Hand ◽  
Paul A. Hohenlohe ◽  
Ted F. Cosart ◽  
Matthew C. Boyer ◽  
...  
Keyword(s):  
Invasive Species ◽  
Rainbow Trout ◽  
Natural Populations ◽  
Cutthroat Trout ◽  
Field Studies ◽  
Selective Advantage ◽  
Hybrid Zones ◽  
Introduced Fish ◽  
Westslope Cutthroat Trout ◽  
Genome Wide

Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome.

Some like it cool? Intermorph comparison of preferred body temperature in a colour-dimorphic snake

2009 ◽  
Vol 59 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Koji Tanaka
Keyword(s):  
Body Temperature ◽  
Environmental Factors ◽  
Laboratory Experiment ◽  
Predation Risk ◽  
Field Studies ◽  
Behavioural Thermoregulation ◽  
Model Species ◽  
High Predation ◽  
Preferred Body Temperature ◽  
Recent Laboratory

AbstractOrganismal characteristics of ectotherms are profoundly affected by body temperature (Tb). Despite constraints imposed by environmental factors, they can adjust Tb by several means. However, if thermoregulatory ability is limited by their own property such as coloration and this constraint affects individual's fitness, selection may promote coevolution of coloration and thermal aspects. I investigated this topic using a colour-dimorphic (melanistic/striped) snake Elaphe quadrivirgata as a model species. Recent laboratory experiment revealed slower body warming in striped individuals than in melanistic individuals. Under this circumstance, one way that striped individuals can manage their slower body warming is to prefer low Tb. Contrary to this prediction, there was no intermorph difference in preferred Tb. Coupled with the results of field studies, I suggest that striped individuals manage their slower body warming by behavioural thermoregulation and that constraints (e.g., high predation risk due to conspicuousness under thermally superior habitats) imposed on melanistic individuals lessen their thermal advantages. The effect of melanism on thermal aspects may not be so advantageous for melanistic animals than generally thought.

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