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. / Forestry, Faculty of / Graduate

The Tropical Andes make up Earth's most species-rich biodiversity hotspot for both animals and plants. Nevertheless, the ecological and evolutionary processes underlying this extraordinary richness remain uncertain. Here, we examine the processes that generate high richness in the Tropical Andes relative to other regions in South America and across different elevations within the Andes, using frogs as a model system. We combine distributional data, a newly generated time-calibrated phylogeny for 2,318 frog species, and phylogenetic comparative methods to test the relative importance of diversification rates and colonization times for explaining Andean diversity at different scales. At larger scales (among regions and families), we find that faster diversification rates in Andean clades most likely explain high Andean richness. In contrast, at smaller temporal and spatial scales (within family-level clades within the Andes), diversification rates rarely explain richness patterns. Instead, we show that colonization times are important for shaping elevational richness patterns within the Andes, with more species found in habitats colonized earlier. We suggest that these scale-dependent patterns might apply to many other richness gradients. Recognition of this scale dependence may help to reconcile conflicting results among studies of richness patterns across habitats, regions, and organisms.

This study was designed to determine the effective internal communication methods and media for knowledge transfer in the manufacturing industry. The research involved the collection of quantitative data through non-probability, convenience sampling. The data was collected using survey questionnaires at three companies in the manufacturing industry namely; Exxaro FerroAlloys, Tubatse Chrome and Amalgamated Beverage Industries. The data was analysed using descriptive and univariate statistical techniques. The study showed that push communication methods and high-media rich communication is preferred for transferring information/explicit knowledge in the manufacturing industry. The most preferred communication methods (top three) for information/explicit knowledge transfer were email followed by newsletters and compulsory meetings. The importance of media richness in transferring tacit knowledge was shown. The study found that High-media rich communication, especially face-to-face, was preferred to transfer and share tacit knowledge. These findings were discussed in the context of existing literature and a number of recommendations were made. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

For the past 5 years we have been conducting a large-scale, multi-habitat inventory of the tardigrades in the Great Smoky Mountains National Park (U.S.A.) as part of the All Taxa Biodiversity Inventory (ATBI) (see www.dlia.org). In terrestrial habitats, we collected moss, lichen, and soil samples from 19 permanent ATBI plots, representing all major land cover types within the park. Each ATBI plot is 100 × 100 m. In each plot, when available, 16 moss samples, 16 lichen samples, and 4 soil samples were collected in paper bags and air dried in the laboratory. Specimens were isolated with LudoxAM centrifugation, and for each sample up to 50 adults plus eggs were individually mounted on microscope slides in Hoyer's medium and identified using phase contrast and DIC microscopy. Additional collections were made in the limestone caves of the Cades Cove region of the park, bird nests, and 13 different streams. To date (1-Jun-06), 589 samples have been collected, and of these 401 have been analyzed, yielding a total of 8133 identifiable tardigrades or, in some cases, species groups. A total of 73 species have been found in the park, 14 of which we believe are new to science. Seven species richness estimators have been developed to predict total species richness (see EstimateS 7.5 software, viceroy.eeb.uconn.edu/ estimates), and these were evaluated by comparing predictions from half of our data to the actual numbers from the total database. The results of this comparison indicate that different estimators work best in different habitats. Using the best estimators in each habitat, EstimateS 7.5 indicates that a total of 96 species are likely to occur throughout the park. Thus, Great Smoky Mountains National Park tardigrade diversity represents 10% of the world's known tardigrade fauna.

In this study I investigate how the biodiversity of vascular plants differs between three slow flowing parts of the stream Juktån in northern Sweden where hydropower has impacted the flow regime and thus the conditions for riparian vegetation. The hypothesis was that species richness would increase with the distance from the hydropower plant due to increasing naturalness of the flow regime. Species richness was investigated since it is a fundamental and important function for the maintenance and quality of ecosystems (Naiman and Décamps 1997). Juktån, where data for the study was collected, receives a static minimum flow of barely 12 % of the yearly natural medium flow released from the hydropower station into the channel (Wisaeus 2014). The minimum flow follows the variation set by the hydropower which deviates from natural seasonal flow variation, which is essential for the germination, growth, and reproduction of many plant species (Poff et al. 1997). The investigation includes a comparison between species richness and richness of 4 functional groups among the three study locations. In addition, analysis of the relationship between environmental variables such as position on the riparian zone (height) and substrate composition were performed. Sikselet that was the slow flowing reach closest to the hydropower station had the highest species richness while Bredselet further downstream had the lowest species richness with Långselet having intermediate species richness. One reason for the pattern in species richness could be that seeds get trapped in weirs located between Sikselet and Långselet. In that case, reintroducing a natural flow regime may not suffice to increase species richness.

abstract: Although many studies have identified environmental factors as primary drivers of bird richness and abundance, there is still uncertainty about the extent to which climate, topography and vegetation influence richness and abundance patterns seen in local extents of the northern Sonoran Desert. I investigated how bird richness and abundance differed between years and seasons and which environmental variables most influenced the patterns of richness and abundance in the Greater Phoenix Metropolitan Area. I compiled a geodatabase of climate, bioclimatic (interactions between precipitation and temperature), vegetation, soil, and topographical variables that are known to influence both richness and abundance and used 15 years of bird point count survey data from urban and non-urban sites established by Central Arizona–Phoenix Long-Term Ecological Research project to test that relationship. I built generalized linear models (GLM) to elucidate the influence of each environmental variable on richness and abundance values taken from 47 sites. I used principal component analysis (PCA) to reduce 43 environmental variables to 9 synthetic factors influenced by measures of vegetation, climate, topography, and energy. I also used the PCA to identify uncorrelated raw variables and modeled bird richness and abundance with these uncorrelated environmental variables (EV) with GLM. I found that bird richness and abundance were significantly different between seasons, but that richness and winter abundance were not significantly different across years. Bird richness was most influenced by soil characteristics and vegetation while abundance was most influenced by vegetation and climate. Models using EV as independent variables consistently outperformed those models using synthetically produced components from PCA. The results suggest that richness and abundance are both driven by climate and aspects of vegetation that may also be influenced by climate such as total annual precipitation and average temperature of the warmest quarter. Annual oscillations of bird richness and abundance throughout the urban Phoenix area seem to be strongly associated with climate and vegetation. / Dissertation/Thesis / Masters Thesis Applied Biological Sciences 2019

Past grassland restoration efforts in the Prairie Pothole Region (PPR) of North America often aimed to restore nesting habitat for waterfowl species. A low-diversity non-native grass and forb seeding mix, known as Dense Nesting Cover (DNC), was frequently used in restoration, and was believed to benefit the broad diversity of wildlife dependent upon restored grasslands. However, grasslands restored with DNC often experience high rates of invasion by non-native vegetation species, and maintenance of these restorations is expensive and requires intensive management. More recently, high-diversity native seeding has been explored as a restoration strategy to decrease the cost of DNC maintenance and provide resources for a greater number of grassland dependent fauna. However, there are gaps in the information concerning how grassland-dependent fauna respond to these restorations, and as such, there is hesitation among land managers to invest in the initial higher cost of high-diversity native seeding mixes until faunal responses are known. The goals of this research were to (1) understand how vegetation diversity, richness, and cover type, variables directly influenced in reseeding restoration, impact grassland-dependent faunal communities; (2) understand how vegetation structure influences the grassland dependent faunal communities to inform post-restoration management activities; and (3) understand how waterfowl and grassland passerines respond to grassland vegetation, structure and landscape variables, in efforts to understand which restoration strategies may be most beneficial to the broader grassland bird community. To perform this study, I selected 26 study sites representing a gradient of vegetation species richness and three cover types; unseeded native grassland (Native), low-diversity and non-native Dense Nesting Cover (DNC), and high-diversity native seed mix (HDM). At each study site, I documented the responses of grassland arthropods, small mammals, grassland birds to vegetation cover type, richness, diversity and structure. I also assessed how vegetation cover type influenced differences in community structure of each of the taxonomic groups. Additionally, because I suspected that bird species are also likely to respond to landscape-level and nest-site level habitat characteristics, I accounted for these variables in our bird models. In Chapter One of this dissertation, I studied the effects of vegetation species richness, diversity and structure on grassland arthropod communities at 23 of our study sites. Arthropod sampling was conducted during July of 2016 using pan traps and sweep net surveys. The goal of using two methods of evaluation was to account for a greater proportion of species in the arthropod community and target taxa that inhabit different parts of the vegetation (i.e., pan traps are better for surveying pollinators and ground dwelling arthropods, whereas sweep net surveys better target arthropods that live higher in the vegetation such as leafhoppers). A total of 25,521 arthropods representing 107 taxonomic families were collected. Vegetation richness and diversity, cover type, percent live vegetation and native cover, and litter depth were important predictors of arthropod community measures, and multivariate analysis of the arthropod community indicated significant differences between Native and DNC sites, which was explained by differences in vegetation richness, percent forb cover, and litter depth. Results suggest that species richness of grassland restoration seeding mixes likely impacts arthropod richness and diversity, and DNC does not produce arthropod communities similar to native grassland. Additionally, because vegetation structural variables were important determinants of arthropod community measures, grassland management practices will influence the resulting arthropod community and influence the success of grassland restoration seed mixes. Results demonstrate the potential for successful restoration outcomes using high-diversity seed mixes, and indicate that low-diversity, non-native seed mixes, such as DNC, do not restore native grassland arthropod communities. In Chapter Two, I assessed the responses of the grassland small mammal community to vegetation cover type, as well as richness, diversity and structure of the vegetation community. During July 2014 to 2016, I used Sherman live traps to survey grassland small mammal communities on 24 study of my study sites. Small mammal abundance was highest at low-diversity DNC sites, and lowest in native grassland. Small mammal diversity was highest at HDM sites and lowest at DNC restoration sites. I selected three focal species to investigate small mammal responses to grassland vegetation including Peromyscus spp., Microtus spp., and Ictidomys tridecemlineatus. Abundances of the different focal taxa were influenced by different vegetation structural variables. Peromyscus spp. abundance was negatively influenced by percent native vegetation cover, Microtus spp. abundance showed yearly variation and was impacted positively by litter depth and negatively by vegetation richness, and Ictidomys tridecemlineatus abundance was influenced by cover type. Small mammal communities of DNC sites differed from Native sites, but HDM was not different from Native or DNC. Ictidomys tridecemlineatus abundance was higher at Native and HDM sites, while DNC sites had higher Peromyscus spp. abundance. Results indicate species-specific management is required to meet small mammal management goals, and diversity of the restoration seed mix is likely to influence grassland small mammal communities. Additionally, DNC is not supporting small mammal communities similar to what is observed at Native grassland sites. In Chapter Three of this dissertation, I investigated the responses of grassland bird communities to vegetation richness, diversity, structure on all study 26 sites. I conducted nest searches for waterfowl during May to July of 2014 to 2016, and searched for grassland passerines and other non-waterfowl bird species during May to July of 2015 and 2016. In 2016, I conducted additional point count surveys to detect bird species that may have been unaccounted for in nest searches. A total of 998 waterfowl nests of nine species, 282 passerine nests of nine species, and 32 nests of 10 other bird species were located. Five hundred and nineteen birds of 20 species were encountered in point count surveys. Richness and diversity of bird nesting and point count communities differed among cover types, and sites restored with HDM seeding had lower bird richness and diversity. Richness and diversity of the vegetation positively influenced the richness and diversity of both the bird nesting and point count communities. Multivariate analysis of the nesting communities indicated significant difference among HDM, Native, and DNC sites, and this was best explained by percent native vegetation cover, vegetation species richness, and vegetation density. Multivariate analysis of the point count communities did not reveal significant difference among cover types, but the structural variables vegetation density and litter depth were important explanatory variables for the ordination. Results study indicate that manipulation of vegetation species richness and diversity that occurs in high-diversity restoration has the potential to influence the grassland bird community, whereas greater vegetation richness and diversity are likely to support more diverse bird communities, but management of vegetation density will be an important management consideration. In Chapter Four, I investigated species-specific responses to vegetation diversity, richness, structure, and landscape variables in order to determine whether management efforts anticipated to benefit a particular taxonomic group of grassland bird species (i.e., waterfowl) are likely to meet the needs of other grassland-dependent birds (i.e., passerines) and to inform management efforts aimed at conserving and creating nesting habitat for grassland waterfowl and passerines. I used generalized linear mixed-models (GLMM) to determine which variables at the landscape, patch, and nest-site level were most influential to the nesting density and daily survival rates (DSR) of our primary focal species. Focal species included five waterfowl species: Blue-winged Teal (Spatula discors; N=365), Gadwall (Mareca strepera; N=173), Mallard (Anas platyrhynchos; N=302), Northern Pintail (Anas acuta; N=64), and Northern Shoveler (Spatula clypeata, N=61), and three species of grassland passerines: Bobolink (Dolichonyx oryzivorus; N=31), Clay-colored Sparrow (Spizella pallida; N=190), and Savannah Sparrow (Passerculus sandwichensis; N=20). Cover type only impacted two of our focal species, Blue-winged Teal and Clay-colored Sparrow, and density of both species was highest at HDM sites and lowest at DNC sites. Vegetation diversity and richness did not impact the nesting density of the majority of our focal species, but Northern Shoveler nesting density was negatively associated with vegetation species richness. DSRs of Northern Pintail and Gadwall were positively associated with vegetation species richness, and Bobolink DSR was negatively influenced by vegetation diversity. Responses to the other landscape-level and vegetation covariates of interest were mixed among species, and little consistency was observed across waterfowl or passerine species. However, at the landscape-level, several waterfowl and passerine species had lower DSRs associated with landscape-level components that contribute to the fragmentation of grasslands including wooded edges, crop fields, and developed areas (i.e., roads and buildings). Results indicated that waterfowl and passerine species respond to different parts of grassland vegetation, and successful management and restoration for nesting grassland birds will require the development of heterogenous habitat that provides resources for the diversity of grassland birds nesting at restored sites. Findings suggest that restoration that involves manipulating diversity, richness, or origin of the vegetation in grasslands through reseeding should be expected to directly influence grassland faunal communities. Because the taxa investigated in this study are responding to different aspects of the vegetation structure, management efforts should be multifaceted, and account for the differing needs of the diversity of grassland fauna dependent upon restored sites. Results also indicated that greater vegetation species richness and diversity results in a more rich and diverse wildlife community, and high-diversity native reseeding should be expected to promote more rich and diverse faunal communities, but successful implementation of high-diversity native reseedings will necessitate proper management of vegetation structure. Finally, all taxonomic groups studied demonstrated positive responses to native grassland habitat, regardless of vegetation richness and diversity. Therefore, preservation of native grassland and promotion of habitat heterogeneity should be prioritized in grassland conservation and restoration efforts.

Owing to climate change, natural forest disturbances and consecutive salvage logging are drastically increasing worldwide, consequently increasing the importance of understanding how these disturbances would affect biodiversity conservation and provision of ecosystem services. In chapter II, I used long-term water monitoring data and mid-term data on α-diversity of twelve species groups to quantify the effects of natural disturbances (windthrow and bark beetle) and salvage logging on concentrations of nitrate and dissolved organic carbon (DOC) in streamwater and α-diversity. I found that natural disturbances led to a temporal increase of nitrate concentrations in streamwater, but these concentrations remained within the health limits recommended by the World Health Organization for drinking water. Salvage logging did not exert any additional impact on nitrate and DOC concentrations, and hence did not affect streamwater quality. Thus, neither natural forest disturbances in watersheds nor associated salvage logging have a harmful effect on the quality of the streamwater used for drinking water. Natural disturbances increased the α-diversity in eight out of twelve species groups. Salvage logging additionally increased the α-diversity of five species groups related to open habitats, but decreased the biodiversity of three deadwood-dependent species groups. In chapter III, I investigated whether salvage logging following natural disturbances (wildfire and windthrow) altered the natural successional trajectories of bird communities. I compiled data on breeding bird assemblages from nine study areas in North America, Europe and Asia, over a period of 17 years and tested whether bird community dissimilarities changed over time for taxonomic, functional and phylogenetic diversity when rare, common and dominant species were weighted differently. I found that salvage logging led to significantly larger dissimilarities than expected by chance and that these dissimilarities persisted over time for rare, common and dominant species, evolutionary lineages, and for rare functional groups. Dissimilarities were highest for rare, followed by common and dominant species. In chapter IV, I investigated how β-diversity of 13 taxonomic groups would differ in intact, undisturbed forests, disturbed, unlogged forests and salvage-logged forests 11 years after a windthrow and salvage logging. The study suggests that both windthrow and salvage logging drive changes in between-treatment β-diversity, whereas windthrow alone seems to drive changes in within-treatment β-diversity. Over a decade after the windthrow at the studied site, the effect of subsequent salvage logging on within-treatment β-diversity was no longer detectable but the effect on between-treatment β-diversity persisted, with more prominent changes in saproxylic groups and rare species than in non-saproxylic groups or common and dominant species. Based on these results, I suggest that salvage logging needs to be carefully weighed against its long-lasting impact on communities of rare species. Also, setting aside patches of naturally disturbed areas is a valuable management alternative as these patches would enable post-disturbance succession of bird communities in unmanaged patches and would promote the conservation of deadwood-dependent species, without posing health risks to drinking water sources. / In Folge des Klimawandels treten in Wäldern vermehrt natürliche Störungen auf, wodurch wiederum die Zahl an nachfolgenden Sanitärhieben (Räumungen) drastisch gestiegen ist. Wie sich natürliche Störungen und Sanitärhiebe auf die biologische Vielfalt und die Bereitstellung von Ökosystemleistungen auswirken können, ist bisher jedoch nur unzureichend bekannt. In Kapitel II nutzte ich langfristige Wassermonitoringdaten und mittelfristige Biodiversitätsdaten über zwölf Artengruppen, um die Effekte von natürlichen Störungen (Windwurf und Borkenkäfer) und Sanitärhieben auf die Konzentrationen von Nitraten und gelöster organischer Kohlenstoffe (GOK) in Bächen und Artenzahl zu quantifizieren. Die Ergebnisse zeigen, heraus, dass natürliche Störungen zu einer temporären Erhöhung der Nitratwerte führen, welche dennoch laut Angaben der Weltgesundheitsorganisation immer noch als unbedenklich eingestuft werden können. Die Sanitärhiebe hatten keinen zusätzlichen Einfluss auf die Nitrat- und GOK-Konzentrationen und daher keinen Einfluss auf die Wasserqualität. Daraus lässt sich schließen, dass sich weder natürliche Waldstörungen in Wassereinzugsgebieten noch die damit verbundenen Sanitärhiebe auf die Trinkwasserqualität aus auswirken. Natürliche Störungen erhöhten die Artenzahlen in acht von zwölf Artengruppen. Zusätzlich erhöhten die Sanitärhiebe die Artenzahlen von fünf Artengruppen, welche auf offene Lebensräume angewiesen sind, verringerte jedoch die Artenzahlen von drei xylobionte Artengruppen. In Kapitel III habe ich untersucht, ob Sanitärhiebe nach natürlichen Waldstörungen zu sukzessiven Veränderungen der Vogelgemeinschaften führen. Hierzu habe ich die taxonomische, funktionelle und phylogenetische Diversität von Brutvogelgemeinschaften aus neun Untersuchungsregionen in Nordamerika, Europa und Asien über die Zeit von 17 Jahren verglichen und analysiert, ob sich das jeweilige Diversitätsmaß verändert, wenn seltene, häufige und dominante Arten unterschiedlich gewichtet werden. Ich konnte zeigen, dass Sanitärhiebe zu signifikant größeren Unterschieden geführt haben als zufällig zu erwarten gewesen sind und dass diese Unterschiede über die Zeit sowohl für seltene, häufige und dominante Arten, als auch für evolutionäre Linien, und funktionelle Gruppen fortdauern. Diese Unterschiede waren am größten für seltene, gefolgt von häufigen und dominanten Arten. In Kapitel IV untersuchte ich wie sich die β-Diversität von 13 taxonomischen Gruppen zwischen ungestörten Wäldern, gestörten und ungeräumten Wäldern sowie gestörten und geräumten Wäldern 11 Jahre nach Windwurf und anschließender Räumung unterscheidet. Die Ergebnisse deuten darauf hin, dass sowohl Windwurf als auch Räumung Änderungen in der β-Diversität bewirken. Windwurf allein jedoch scheint diese Änderungen in der β-Diversität innerhalb der Behandlung bewirken zu können. Über ein Jahrzehnt nach dem Windwurf war der Effekt des Sanitärhiebes auf die β-Diversität innerhalb der Behandlung nicht mehr nachweisbar. Der Effekt auf die β-Diversität zwischen den Behandlungen blieb jedoch bestehen, wobei sich die xylobionten Gruppen und seltenen Arten stärker veränderten als die nicht-xylobionten Gruppen oder häufigen und dominanten Arten. Basierend auf diesen Ergebnissen schlage ich vor, dass der Einsatz von Sanitärhieben sorgfältig gegen ihre langfristigen Auswirkungen auf Gemeinschaften seltener Arten abgewogen werden muss. Zusätzlich, besteht mit dem Belassen von natürlich gestörten Waldgebieten eine wertvolle Managementalternative, da diese Flächen eine natürliche Entwicklung von Vogelgemeinschaften ermöglichen und xylobionte Arten fördern, ohne dass die Trinkwasserqualität negativ beeinträchtigt wird.

Boreal forests in Europe are intensively managed for timber and pulp production, resulting in decreased biodiversity, and in the long-term leading to a reduced number of functioning ecosystem services. To develop a more sustainable forest management it is important to investigate what features and habitat types are needed to preserve a high diversity of species within the forestry landscapes. Birds are a suitable study taxon since their ecology is well known and their diversity often mirrors the diversity of other taxa. This study investigated how different habitat types, for example, forest stand composition and age of forest etc., influence the diversity, species richness and abundance of forest bird species in boreal forestry landscapes in Sweden. I expected that the percentage of deciduous forests and older forests would increase the diversity and richness of forest birds, while spruce forests and young forests would have negative effects. Further, I expected mixed forest stands to be more diverse regarding forest birds than pure forest stands. The sites for this study consisted of fiveforestry landscapes in south Sweden, with both active forestry and multifunctional forestry areas. The results showed positive effects of the percentage of deciduous forests, wetlands, older forests, mixed coniferous forests, and pine forests on species richness, abundance, and diversity of forest bird species. However, deciduous forests and older forests had the strongestpositive influence on species richness and diversity. Furthermore, I did not find evidence that mixed forest stands have a higher diversity or species richness than monocultures of only spruce and pine respectively.

No description available.