scholarly journals The effect of fire on soil oribatid mites (Acari: Oribatida) in a South African grassland*

Zoosymposia ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 210-220 ◽  
Author(s):  
ELIZABET A. HUGO-COETZEE ◽  
NICO L. AVENANT
Keyword(s):  
Species Richness ◽  
South African ◽  
Fire Regime ◽  
Residual Effect ◽  
Oribatid Mites ◽  
Fire Disturbance ◽  
Management Tool ◽  
Disturbance Factor ◽  
And Control ◽  
The Impact

Fire is a natural disturbance factor in southern African grasslands, and has become an important management tool for conservation of these habitats. Information on the impact of fire on any aspect of biodiversity will assist land managers to make more informed decisions on a fire regime that will conserve biodiversity in these grasslands. This is the first study to examine the responses of mite assemblages to fire disturbance in South African grasslands. The study was conducted in the Erfenis Dam Nature Reserve in central South Africa. An area of the Reserve was burned with a fast, hot fire while another area was left unburned as a control. Soil oribatid mites were collected over a period of one year from the burned and control areas. Oribatid assemblages exhibited seasonal patterns, with species richness and abundance slightly higher in early and late autumn and early spring. Four months after fire, there was no residual effect of fire on total abundance and species richness. However, species composition and the seasonal relative abundances of particular species, e.g. Multioppia wilsoni Aoki, 1964, Scheloribates confusia Coetzer, 1968 and Anellozetes auriculatus (Mahunka, 1984), differed between burned and control plots, demonstrating how targeted species can be investigated as indicators of post-fire recovery.

scholarly journals The use of the South African Diatom Index as a concervation management tool for Hewitt’s Ghost frog

2012 ◽  
Vol 31 (1) ◽  
Author(s):  
V. Botha ◽  
C. Weldon ◽  
J.C. Taylor
Keyword(s):  
South African ◽  
Distribution Patterns ◽  
Management Tool ◽  
The South ◽  
Diatom Index ◽  
The Impact

Distribution patterns of diatoms were investigated to determine the impact ofshading on the distribution of diatomes, which form the main diet of the endangered frogspecies, Heleophryne hewitti.

scholarly journals Multiple comparisons of diversity indices invaded by Lantana camara

2020 ◽  
Author(s):  
H. Qureshi ◽  
T. Anwar ◽  
N. Habib ◽  
Q. Ali ◽  
M. Z. Haider ◽  
...  
Keyword(s):  
Species Richness ◽  
Diversity Index ◽  
Diversity Indices ◽  
Lantana Camara ◽  
Native Plant ◽  
Heterogeneous Nature ◽  
Significant Magnitude ◽  
Native Plant Diversity ◽  
And Control ◽  
The Impact

Abstract Current study assessed the impact of Lantana camara invasion on native plant diversity in Pothohar region of Pakistan. The approach used for study was random samplings and comparisons of diversity indices [number of species (S), abundance (N), species richness (R), evenness (Jꞌ), Shannon diversity index (Hꞌ) and Simpson index of dominance (λ)] with two categorical factors i.e., invaded and non-invaded (control). Control plots harboured by an average of 1.74 more species/10m2. The control category was diverse (Hꞌ=2.56) than invaded category (Hꞌ=1.56). The higher value of species richness in control plots shows heterogeneous nature of communities and vice versa in invaded plots. At multivariate scale, ordination (nMDS) and ANOSIM showed significant magnitude of differences between invaded and control plots at all sites. The decrease in studied diversity indices in invaded over control sites indicated that plant communities become less productive due to Lantana invasion.

scholarly journals Separation of ownership and control in South African-listed companies

2013 ◽  
Vol 16 (3) ◽  
pp. 316-345 ◽  
Author(s):  
Blanché Steyn ◽  
Lesley Stainbank
Keyword(s):  
South African ◽  
Stock Exchange ◽  
Listed Companies ◽  
South African Context ◽  
Valuable Contribution ◽  
Self Interest ◽  
African Context ◽  
Using Data ◽  
And Control ◽  
The Impact

This article tests the separation of ownership and control in South African-listed companies that leads to the divergence of interest between shareholders and directors. Where listed companies are owned by so many shareholders that their diffused shareholding results in negligible control over the directors who manage the assets of the company, it is likely that the directors will manage and direct the company to maximise their self-interest to the detriment of the interest of the shareholders. The separation of ownership and control and the maximisation of self-interest are central themes in the agency theory. Researching their validity in a South African context where the market is less liquid and the stock exchange is significantly smaller can add a valuable contribution to the continuing debate on corporate governance in the country. The article analyses 186 listed South African companies using data extracted over four years to test whether there is separation of ownership and control and whether such separation leads to the maximisation of self-interest. Data were extracted for the years 2005 and 2006, using the shareholding in 2006 to determine control, and for the years 2009 and 2010, using the shareholding in 2010 to determine control. Directors’ remuneration as a percentage of assets was used as a proxy for the maximisation of directors’ interest, and profit attributable to shareholders as a percentage of assets was used as a proxy for the maximisation of shareholders’ interest. These proxies were used to test the impact of control during the two controlling periods, namely 2006 and 2010.The article finds that the majority of listed companies in South Africa are controlled by a dominant shareholder. However, there are still a significant number of companies where the directors have de facto control. Contrary to the expectation that companies controlled by directors will aim to maximise directors’ remuneration, or companies controlled by shareholders will aim to maximise profit attributable to shareholders, this article finds the opposite to be true. This is possibly an indication that the controlling parties might consider factors other than their direct financial self-interest, or that there is an inherent cost associated with control.

Does 'acoustic anchoring' reduce post-translocation dispersal of North Island robins?

2011 ◽  
Vol 38 (1) ◽  
pp. 69 ◽  
Author(s):  
David W. Bradley ◽  
Calum E. Ninnes ◽  
Sandra V. Valderrama ◽  
Joseph R. Waas
Keyword(s):  
Radio Telemetry ◽  
Control Release ◽  
Release Site ◽  
Immediate Release ◽  
Control Site ◽  
Management Tool ◽  
And Control ◽  
Release Location ◽  
The Impact

Context Animal translocations are an important conservation tool; however, post-release dispersal can hinder successful population establishment. Playback of conspecific song attracts dispersing individuals in some species, although its application following animal translocation has yet to be rigorously investigated. Aims To determine whether conspecific song can be used as an ‘acoustic anchor’, we adopted an experimental approach during the translocation of 60 North Island robins (Petroica longipes). Methods At one of two release locations, we broadcast song at natural rates from four speakers (4 h per morning), for 9 days following release; we set the second release location as a control where identical conditions were established but no playback occurred. To assess the impact of playback, we monitored speaker and control locations, surveyed tracks around the release areas, and radio-tracked robins over nine playback days and an additional 9 days. Key results Most robins left both immediate release areas; however, our results showed that (1) more robins (6 birds on 14 of the 18 days), in particular females (3 birds), approached the playback location than the ‘flagged’ control location (3 male birds on 5 of the 18 days), (2) individual robins returned to the playback location repeatedly, unlike those at the control site, and (3) robins also visited the playback location longer after playback than they did silent control locations. In contrast, radio-telemetry data from five robins suggested that general dispersal was not influenced by playback. Two radio-tracked females moved over long distances (some to >3 km from their release location), whereas two radio-tracked males remained relatively close to the release sites. Conclusions We demonstrated a short-term attraction effect of playback over a period of several weeks for some birds, particularly females. In contrast, we detected fewer birds over a shorter period at the silent control release site, where no females were detected. However, long-term monitoring at both sites suggested that the effect of playback on reducing post-release dispersal was transitory. Implications The lack of a clear and lasting effect of acoustic anchoring on dispersal in the present study has provided information on the limited utility of song playback as a conservation management tool for this species. Consideration of the species’ ecology and suitability for ‘acoustic anchoring’ must be made before playback is employed as a conservation measure to reduce excess post-translocation dispersal.

scholarly journals Impact of Disturbances on Species Diversity and Regeneration of Nepalese Sal (Shorea robusta) Forests Managed under Different Management Regimes

Earth ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 826-844
Author(s):  
Uttam Chapagain ◽  
Binod P. Chapagain ◽  
Sunil Nepal ◽  
Michael Manthey
Keyword(s):  
Species Richness ◽  
Protected Area ◽  
Buffer Zone ◽  
Community Forest ◽  
Managed Forest ◽  
Shorea Robusta ◽  
Management Regime ◽  
Disturbance Factor ◽  
Management Regimes ◽  
The Impact

Sal (Shorea robusta) forests, a dominant forest type in Nepal, experience different disturbance intensities depending on management regimes. This study compares the impact of disturbance on Nepalese Sal forests, which are managed on three major management regimes: protected area, state-managed forest, and buffer zone community forest. Using a systematic sampling approach, we sampled 20 plots, each covering 500 square meters, and nested plots within each main plot to measure pole and regeneration for each management regime. We recorded forest characteristics including tree species, counts, diameter, height, crown cover, and disturbance indicators. We compared forest attributes such as diversity indices, species richness, and stand structure by management regime using analysis of variance and regression analysis. The forest management regimes were classified into three disturbance levels based on disturbance factor bundles, and the buffer zone community forest was found to have the highest disturbance while the protected forest had the lowest disturbance. Species richness, diversity, evenness, abundance, density and basal area were higher, but regeneration was lower in protected area and state-managed forest compared to the buffer zone community forests. This suggests positive impacts of moderate disturbance on regeneration. The management plan should prioritize the minimization of excessive disturbance to balance forest conservation and provide forest resources to local users.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

Research Participation Experiences of Informants of Suicide and Control Cases

Crisis ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. 238-246 ◽  
Author(s):  
Paul W. C. Wong ◽  
Wincy S. C. Chan ◽  
Philip S. L. Beh ◽  
Fiona W. S. Yau ◽  
Paul S. F. Yip ◽  
...  
Keyword(s):  
Ethical Issues ◽  
Research Participation ◽  
Self Report ◽  
Initial Contact ◽  
Psychological Autopsy ◽  
Autopsy Study ◽  
The People ◽  
And Control ◽  
The Impact

Background: Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. Aims: (1) To investigate whether informants of suicide cases recruited by two approaches (coroners’ court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. Methods: A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. Results: The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. Limitations: The acceptance rate for our original psychological autopsy study was modest. Conclusions: The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

Using Work Domain Analysis to Evaluate the Impact of Digitization on Command and Control

2008 ◽  
Author(s):  
Daniel P. Jenkins ◽  
Neville A. Stanton ◽  
Paul M. Salmon ◽  
Guy H. Walker
Keyword(s):  
Command And Control ◽  
Domain Analysis ◽  
Work Domain Analysis ◽  
And Control ◽  
The Impact ◽  
Work Domain
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