Today many saproxylic species are threatened because of habitat decline in Europe. Hollow trees represent a great part of the habitats that saproxylic species use. Since hollows takes a long time to develop, management actions are needed to prevent the extinction of saproxylic species. The aim of this study was to investigate the succession of saproxylic beetle species in artificial habitats in the form of wooden boxes. Wooden boxes were filled with a potential substrate and placed at different distances (0-1800 m) from oak hollow hot spots. In addition to the start mixture, four different additional substrates were added. In total, 4510 specimens of 114 saproxylic beetle species were sampled in 43 boxes over ten years. The specimens of tree-hollow species, wood rot species and nest species increased with 38% from the fourth to the final year but species richness decline from 47 to 29, respectively. A dead hen had a tendency for attracting more species but the small effect of different added substrates diminished over the years and had no significant effect on species richness after ten years. There was a higher similarity in species richness after ten years between the boxes and real hollow oaks. In conclusion, the artificial habitat developed into a more hollow like environment, with fewer but more abundant wood mould specialists, during ten years. This study clearly shows that the wooden boxes are used as habitats for saproxylic species as the boxes seems to develop into a more hollow-like habitat with time.

No description available.

Wildfire is the primary natural disturbance in Interior Cedar-Hemlock (ICH) forests, and since the mid-20th century, forest harvesting (clearcutting, in this case) has become the primary anthropogenic disturbance type. Forest management in British Columbia is currently governed by a paradigm that maintains that biological diversity can be preserved by utilizing forest harvesting regimes that closely mimic "natural" disturbance regimes, but a question remains as to how closely these regimes mimic wildfire disturbances. More specifically, how do clearcutting and wildfires compare in their effects on the structure and composition of early-successional ICH plant communities? This study compares vegetation structure, composition, relative abundance and diversity among 39 sites that experienced either a stand-replacing fire or a clearcut within the last 40 years. Sites of different ages and disturbance types were located within the wet cool ICHwkl and very-wet cool ICHvk I biogeoclimatic variants near Revelstoke, B.C. For each site, overstory structural characteristics (tree and snag diameters, basal area and density), overstory composition, and surface fuels (volume of coarse woody debris (CWD)) were assessed. Understory vegetation percent cover, species richness, composition and diversity were also determined. Linear regression analysis was used to examine differences in each of these variables between disturbance types, over time. The trends in structural legacies (especially snag and CWD dynamics) varied greatly between wildfire and clearcut sites. Compared to burned sites, clearcut sites exhibited patterns of accelerated succession in several characteristics (overstory tree regeneration, vegetation cover and understory species richness) due to planting treatments and pre-disturbance relicts. Understory species composition also varied between disturbances, with clearcut sites containing more shade-tolerant survivors initially. Both disturbance types had similar levels of floristic diversity during early succession. These results suggest that clearcut harvesting may not emulate stand-replacing fires in terms of impact on early ICH plant succession in any aspect but diversity. However, it is unclear if these early-successional differences will continue through time. There is a need for further research in this ecosystem, as well as any other ecosystems where emulation silviculture is applied, in order to confirm that silvicultural effects mimic those of natural disturbance regimes.

Présentement, les décisions reliées à la succession forestière sont prises par les aménagistes à partir du meilleur de leurs connaissances et des informations disponibles. Toutefois, dans un contexte de réduction des incertitudes dans le calcul de la possibilité forestière (CPE), la caractérisation de l'importance de la succession cyclique pour la forêt boréale continue du Québec constitue un premier pas pour combler le manque d'information sur l'évolution des peuplements. Pour l'instant, la succession directionnelle (c.-à-d. lorsque l'intervalle entre deux perturbations majeures est suffisamment long pour que les espèces de fin de succession qui se sont établies en même temps que les espèces pionnières remplacent celles-ci dans la canopée) est de facto supposée par les aménagistes. À l'opposé, la succession cyclique n'est pas un concept très bien défini dans la littérature scientifique. Plusieurs définitions circulent et il était nécessaire d'harmoniser les termes pour en clarifier les concepts. Nous avons défini la succession cyclique, comme étant le maintien de la dominance de l'espèce pionnière dans la canopée au-delà de la cohorte initiale. De plus, nous avons supposé que l'absence de gaules et de semenciers d'espèces de fin de succession dans un peuplement pionnier déjà bien établi était une indication d'un site soumis à la succession cyclique et donc, que la dynamique successionnelle cyclique était étroitement reliée à l'exclusion des espèces de fin de succession. L'étude a permis de vérifier s'il y avait une plus grande probabilité de succession cyclique dans une région donnée lorsque la sévérité et la fréquence des perturbations y étaient élevées ou si la probabilité était avant tout attribuable à des conditions écologiques locales (différenciation de niche) où à des facteurs régionaux (interaction climat et régime de perturbations). Notre étude visait à quantifier (1) la présence de peuplements pionniers dans le paysage de la forêt boréale de l'est du canada et (2) la proportion de ces peuplements qui montrent une succession cyclique. Selon nos analyses, les effets des facteurs locaux sur l'occurrence de la succession cyclique n'ont pas été observés, tandis que nous avons pu observer qu'il y avait une plus grande probabilité de succession cyclique dans une région lorsque la sévérité et la fréquence des perturbations y étaient élevées. Bien qu'il semble que des perturbations naturelles fréquentes et sévères, laissant peu de semenciers locaux et détruisant les banques de graines, peuvent conduire à une extirpation locale des espèces de fin de succession, nous avons remarqué que le chevauchement, sur une courte période de temps, de perturbations d'origine anthropique (c.-à-d. colonisation et exploitation) avec celles d'origine naturelle (c.-à-d. feux et épidémie) favorise davantage la mise en place d'une succession cyclique dans la sapinière. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : succession cyclique, forêt boréale, espèces pionnières, état stable alternatif, accident de régénération

Widespread abandonment of agricultural land has occurred in northeastern North America over the past two centuries. Soil carbon often increases as sites naturally regenerate towards perennial grasslands or forests. Understanding the large-scale controls on the potential and rate of soil carbon sequestration is necessary in order to evaluate the significance of this sink to the global carbon cycle. Furthermore, we need to understand the key roles soil microorganisms play in regulating ecosystem processes through their control over soil carbon and nitrogen dynamics. Such studies are rare at the century long time scale of temperate forest succession. Additionally, research has taken place primarily on productive agricultural soils, while abandonment is more common on marginal agricultural soils. We characterized patterns of total and labile soil carbon and nitrogen and microbial dynamics in mature forest and adjacent agricultural field sites, and in replicated chronosequences of forest successional sites on marginal soils of southeastern Ontario, Canada. Total soil carbon was significantly depleted in the top 10 cm of current agricultural fields as compared to forest sites and increased at a rate of 10 g C m-2 yr-1 across our 100-year chronosequences. There was no difference in carbon loss or accumulation over time in three soil types differing in texture and parent material, suggesting that time since abandonment is more important than soil type in determining carbon accumulation within this climatic region. In contrast, free-light fraction carbon did not increase over time and thus most carbon accumulated in pools with slower turnover times. Soil microbial biomass carbon and nitrogen increased significantly following abandonment and our results strongly suggest that microbial growth during all phases of succession was limited by carbon supply. In contrast, net nitrogen mineralization and nitrification rates during mid-summer did not change consistently over the first 100 years following agricultural abandonment. Therefore, inorganic nitrogen supply rates into the plant available pool were similar across the entire successional sequence. Together, the results of these two studies demonstrate the potential for carbon sequestration in abandoned agricultural soils across this climatic region and highlight the importance of plant-soil interactions for understanding carbon cycling during ecosystem development. / Thesis (Master, Biology) -- Queen's University, 2007-12-14 10:04:57.395

No description available.

No description available.

Abstract not available. / Thesis (Ph.D.)-University of Durban-Westville, 1998.

This study explores the reasons why succession planning is imperative in an organisation. The study focuses on Nedbank Homeloans’ KZN Operations at the head office in central Durban and includes the views of the office staff about the salient issues in regards to succession planning. A comprehensive literature review provides a background to the study. A number of reasons for the need for succession planning have been provided by various writers, and these constitute the point of departure for the study. The broad themes that impact on the success of succession planning are identified as being the need to retain talent, to develop skills, and to enhance the benefits that can be derived from implementing succession planning in an organisation. In relation to these themes, the main objectives of the study were the following: to determine what benefits the organisation may achieve from implementing a succession plan; the significant impacts of not having a strategic succession plan; what an organisation can do to retain talented and competent employees; the role an organisation can play in sustaining skilled and talented people; and if the implementation of succession planning can support the career paths of employees not just up a specialised ladder but across a continuum of professional competence. The fieldwork was exploratory in nature, with a questionnaire being administered to seventyseven home-loan staff across the different levels of function. The Statistical Package for Social Sciences (SPSS) was used to analyse the data. Various statistical techniques such as Cronbach’s Alpha were applied to test reliability.An in-depth analysis of the results of the questionnaire was performed. The results of the study were evaluated and various recommendations are made. An implementation plan is provided to aid in the implementation process. / Thesis (MBA)-University of KwaZulu-Natal, Westville, 2010.

As a result of the chronic nursing shortage, the ongoing retirements of an aging generation, and a general lack of interest from nurses to become nurse managers, there is valid concern around the development and sustainability of future nurse managers. The purpose of this qualitative study was to explore nurse managers’ perceptions and experiences of assuming a nurse manager position. In addition, the study highlights the organizational leadership practices that influenced nurses to become nurse managers. Using a modified version of Collings and Mellahi’s (2009) strategic talent management framework, two major themes emerged from the data giving insight into nurses becoming nurse managers. Broadening a nurse’s professional lens was considered by nurse managers to be an important theme relevant to understanding factors that motivated participant’s to become nurse managers. Shaping a nurse’s career path was the second theme that captured the leadership practices of existing leaders that influenced nurse’s becoming a nurse manager. The findings of this research were consistent with the literature related to understanding work motivations, as well as effective leadership practices believed to support career aspirations in nursing leadership. Implications for nursing leadership and practice were shared; recommendations for further research were discussed.