Does pre-dispersal seed predation limit reproduction and population growth in the alpine clonal plant Geum reptans ?

We studied the impact of the seed damaging gall midge larva Geomyia alpina on its perennial alpine host plant Geum reptans. We analysed the effect of seed predation on reproduction by seeds, i.e. seed number, seed mass, and seed viability and on growth and clonal propagation of non-protected plants in comparison to plants protected from predation by an insecticide. Additionally, we assessed the consequences of seed predation for population growth using matrix projection modelling. Seed predation resulted in a decrease in total seed mass per flower head by 23.8% in non-protected plants (P<0.05). Individual seed mass decreased with increasing infestation intensity (P<0.05). Seed number remained unaffected because the sucking feeding behaviour by gall midge larvae does not evoke seed abortion. Percent germination of seeds from non-protected plants was reduced by 97.9% compared to seeds from protected plants. According to reduced seed viability, modelling revealed a decrease in population growth rate from λ=1.055 to λ=1.041. Predation did neither influence total plant biomass nor biomass fractions. But stolon dry-weight of non-protected plants increased by 24.1% (P<0.05), which may indicate a trade-off between sexual reproduction and clonal propagation. Our results demonstrate that despite substantial reduction of viable seeds, predation by gall midge larvae only slightly affected population growth of G. reptans suggesting that in this alpine species, persistence by longevity and clonal propagation can balance potential seed losses by predation, at least for local population growt

There’s No “Gender” in Team: Developing State Policies for the Inclusion of the Transgender Interscholastic Athlete

The transgender athlete is a relatively new concept challenging the norm of gender division in sports. Multiple states across the United States have yet to update their policies to include the transgender athlete in interscholastic athletics. State policies that do include transgender student athletes are currently being challenged on the grounds that they violate Title IX of the Educational Amendments to the 1964 Civil Rights Act. This review considers the different state policies dictating the inclusion of transgender student athletes in school sports. After evaluating the impact of omitting transgender students from participating on sports teams, this review maintains that every state should implement an inclusive policy to avoid discriminating against young transgender students. While these individuals have many obstacles to face in life, high school athletics should not be one of them

Population dynamics of a long-lived alpine plant with sexual and clonal reproduction

This thesis focuses on the demography, reproduction, and pre-dispersal seed predation of the alpine clonal plant Geum reptans. In chapter 2, I studied the population dynamics of G. reptans, thereby I particularly addressed the relative importance of sexual vs. clonal reproduction for population growth in this longlived species. In chapter 3, the balance between sexual and clonal reproduction in plants of different sizes and the frequency of life-cycle stages in G. reptans were studied in respect to the environmental gradients altitude and succession. In chapter 4, I demonstrated the impact of a host-specific seed predator on reproducetion and population growth of G. reptans. G. reptans is a typical pioneer species of recently deglaciated areas showing also high persistence in late successional communities. Since G. reptans occurs along broad ranges of altitude and succession, its environment is mainly characterised by high natural fragmentation, frequent disturbances, and sharp gradients of climatic conditions which may constrain growth and reproduction. Many plants adapted to alpine habitats are slow-growing, thereby showing long life-spans and pronounced clonal reproduction (Hartmann 1957; Billings & Mooney 1968; Bliss 1971). Longevity and particularly the ability for clonal growth can result in high individual persistence for centuries or even for hundreds of years (Steinger et al. 1996; Molau 1997; Morris & Doak 1998). Generally, the importance of clonal growth tends to increase with altitude (Bliss 1971; Klimeš et al. 1997). Contrary, there is large evidence that recruitment from seeds declines with altitude (e.g. Jolls & Bock 1983) supporting the assumption that in high alpine habitats, local population dynamics of many species are strongly dominated by clonal growth (cp. Crawley 1990; Eriksson 1992; Silvertown et al. 1993). However, alpine pioneer species are characterised by high seed production (Stöcklin & Bäumler 1996). Thus, sexual reproduction providing dispersal and colonisation of new sites must be of particular importance for a pioneer species situated in the patchy alpine landscape. Nevertheless, knowledge about population dynamics of alpine plants is scarce and the importance of sexual vs. clonal reproduction for population growth remains largely unclear. In a demographic study in two field populations, I focused on the relevance of life-cycle stages as well as on the significance of sexual and clonal reproductive transitions for population dynamics in long-lived G. reptans (chapter 2). Implying a trade-off between sexual and clonal reproduction in G. reptans depending on meristem availability, the balance between both reproductive modes is likely to vary depending on different selection pressures. Environmental heterogeneity is considered to promote genetic variation in life-history traits (Stratton 1994; Prati & Schmid 2000) and large-scale environmental gradients are well known to result in locally adapted genotypes (Clausen et al. 1947; Linhart & Grant 1996). The question, if the relationship between sexual and clonal reproduction varies in contrasting altitudes and successional stages is one of the main topics in this thesis (chapter 3). Opposing selection pressures for reproductive traits is predicted by metapopulation theory (e.g. Olivieri et al. 1995; Husband & Barrett 1996): In recently established populations, traits that enhance dispersal should be favoured since they are more likely founded by genotypes with high dispersal ability. With increasing population age, within-population selection should act against dispersal resulting in a decrease in sexual reproduction whereas clonal reproduction increases. If the importance of clonal growth increases with altitude, in high altitude plants more allocation to clonal reproduction at the expense of sexual reproduction is expected. In 20 populations of G. reptans, I compared the proportion of clonal reproduction in low vs. high altitude habitats and in early vs. late successional habitats and studied the influence of plant size on reproduction of this species. Pre-dispersal seed predation can substantially influence the relative reproductive success of individuals by limiting seed production (e.g. Louda & Potvin 1995; Briese 2000). Moreover, evidence is given, that seed consumption prior to dispersal can limit a species population growth and therefore may have severe consequences for its persistence (e.g. Louda 1982; Kelly & Dyer 2002). However, effects of pre-dispersal seed predation on population dynamics are still poorly understood. A reduction in seed output may be of particular importance in high alpine habitats, where recruitment from seeds can be strongly limited by harsh environmental conditions (Scherff et al. 1994; Forbis 2003). Many populations of G. reptans show heavy predation by host-specific gall midge larvae feeding on developing seeds. In an exclusion experiment, I used insecticide to study the consequences of pre-dispersal seed predation on reproduction in a population of G. reptans (chapter 4). Since this species does not form a persistent seed bank and immigration of seeds from other sites is negligible (Tackenberg & Stöcklin, unpublished), impacts of seed loss are expected to directly affect recruitment. I used a greenhouse germination experiment to test for seed viability due to predation and matrix modelling allowed predicting consequences for population growth based on the observed seed loss. Population dynamics of Geum reptans: Population dynamics of Geum reptans are mainly characterised by slow yearly increase and longevity which are typical features of many alpine plants as well as of pioneer species of primary successions. Despite considerable variation in growth rates (�) among sites and years, dynamics in both populations were very similar. However, a slightly negative � in one year out of four mainly resulting from higher adult mortality indicates that population dynamics of slow-growing G. reptans are likely to be sensitive to environmental stochasticity. Sexual and clonal reproduction occurred regularly in both populations during the study period but the frequency of reproducing adults was always low. This was demonstrated for populations of G. reptans situated in different environments (chapter 3), suggesting that yearly variable availability of resources for reproduction and the cost of reproduction may cause annually variation in reproductive output similar to mast seeding in trees (Webb & Kelly 1993). Interestingly, in G. reptans sexual reproduction plays an equally important role for population growth as the reproduction by stolons. Thus, my results clearly contradict the general assumption, that the role of sexual reproduction in clonal plants from high altitudes is mainly restricted to the maintenance of genetic variation and longdistance dispersal. Nevertheless, the two reproductive modes may have different significance for population dynamics: The constantly higher establishment of stolons compared to seeds suggests that clonal propagation serves as a low-risk alternative compared to more unpredictable and unsecured establishment from seeds. Reproduction by stolons alone may guarantee continuously slow population growth leading to a positive � and thereby assuring persistence of the population even in unfavourable periods. Although germination occurred regularly in both studied populations, percent germination varied by nearly 200% among years implying that seed recruitment in G. reptans may be particularly susceptible to environmental variation. On the other hand, in favourable years, reproduction by seeds may be an important contributor to population growth. In G. reptans, population growth rate was much more sensitive to changes in the survivorship of adults than to growth or to reproductive parameters confirming the importance of persistence. Long-lived species living in stressful environments and exhibiting low recruitment rates may be particularly vulnerable to adult mortality. Since G. reptans as a species of glacier forelands is highly subject to changes in habitat conditions, it is a reasonable strategy for this species to privilege investments to maintenance of adults at the expense of growth and fecundity. Thus, adult longevity is expected to serve as a buffer against temporal variation which may be of particular importance in frequently disturbed alpine habitats. My results indicate that even in harsh alpine environments, population growth of a long-lived species does not rely on clonal reproduction alone. Variation of sexual and clonal reproduction: In Geum reptans, the relationship between sexual and clonal reproduction largely varied among populations. However, the variation in reproductive behaviour could only be explained to a small degree by contrasting altitudes or successional stages. There may be two possible explanations for this result: Firstly, reproductive differences between populations may reflect mainly small-scale variation in environmental conditions not related to altitude or succession overriding the effects of gradients. Secondly, high phenotypic plasticity may restrict or even prevent adaptation to contrasting environmental conditions. Highly plastic genotypes have been demonstrated for species dispersed over broad geographic and environmental ranges showing little genetic or morphological differentiation (Williams et al. 1995; Hermanutz & Weaver 1996). Accordingly, G. reptans as a colonising species may have the capacity of broad plastic responses allowing rapid spread into new habitats without experiencing adaptation through selection. Additionally, high individual variation in stolon and flower head production could add to population variability which was also detected in chapter 2. Nevertheless, in comparison with intermediate populations, clonal reproduction increased in populations at high altitude as well as at low altitude which was partly in accordance with my expectations. The higher frequency of stolons at high altitudes demonstrates that abiotic environmental conditions may restrict seedling establishment leading to a higher fraction of clonal reproduction. At low altitudes, habitats are often characterised by increased inter-specific competition and G. reptans is very susceptible to competition (Pluess & Stöcklin 2005). Additionally, seedlings lacking the support of adults in contrast to vegetative off-spring may be particularly vulnerable for crowding what might explain the higher proportion of stolons also found in low altitude habitats. However, sensitivity analysis of matrix projection models can reveal the direction and intensity of selection on life-history characteristics of species (van Groenendael et al. 1988). Since sensitivity of � was highest to stasis of small adults and very low to reproductive transitions (chapter 2), it is expected that in G. reptans, traits promoting persistence may be stronger under selection compared to reproductive behaviour. In a common garden experiment studying the effects of population origin and environment in G. reptans, in spite of high variation, differences in reproductive behaviour were not explained by population origin from successional gradients supporting the assumption that adaptation in reproductive behaviour to contrasting habitats is limited in this species (Pluess & Stöcklin 2005). My results suggest that the observed variation among populations in the frequency of clonal reproduction largely results either from differences in local environmental conditions and probably also from random drift among populations. Another factor altering the relationship of sexual and clonal reproduction was plant size. In G. reptans, the number of reproductive meristems as well as the probability of producing flower heads and stolons simultaneously increased with the number of rosettes. Accordingly, small plants being rather limited in resources invested preferentially in low-cost stolon production. Larger plants having more resources available invested into both reproductive modes thereby tending to prefer sexual reproduction confirming once more the importance of sexual reproduction for a clonal alpine plant (chapter 2). Pre-dispersal seed predation: Pre-dispersal seed predation by gall midge larvae heavily decreased seed mass in Geum reptans causing seed viability to be substantially reduced (-98%). However, matrix modelling revealed that the population growth rate (�) was only slightly affected by the observed seed loss suggesting that persistence of G. reptans does not depend on seed production alone. In natural habitats, sexual reproduction and seedling establishment are very likely to show high inter-annual variation depending on environmental conditions and individual variation in reproduction (chapter 2). While high seed production can rapidly increase population growth, low seed availability does not necessarily lead to a negative population growth since continuous clonal reproduction can balance potential seed losses. Accordingly, population growth rate would only decrease as a result of a general lack of reproduction. However, since elasticity analysis revealed that � is most sensitive to survival of adults, limitation in sexual reproduction by seed predation is not expected to have more than only slight effects on population growth. Thus, the local abundance of G. reptans does not critically depend on seed supply suggesting that population dynamics is probably not limited by pre-dispersal seed predation which has also been shown for other perennial species (Andersen 1989; Fröborg & Eriksson 2003). Nevertheless, predation could be an important factor generating differences in the reproduction of individuals, thereby decreasing effective population size, and thus facilitating genetic change, particularly genetic drift (Crawford 1984; Heywood 1986). Surprisingly, seed predation resulted in an increase in stolon dry-weight in predated plants suggesting a change in resource allocation due to less resources used for seed ripening after pre-dispersal seed predation favouring clonal reproduction. However, as leafy stolons of G. reptans are expected to mainly support themselves, it seems unlikely that a higher stolon mass may increase clonal establishment and therefore directly compensate for reduced sexual establishment due to seed loss. Although pre-dispersal seed predation by host-specific gall midge larvae did not limit population growth of G. reptans, the production of viable seeds was substantially reduced. Therefore, infested populations may have reduced amounts of seeds available for dispersal and colonisation of new sites which may be of particular relevance in the naturally fragmented alpine landscape. Conclusions In summary, my results demonstrate that sexual and clonal reproduction both have an equally important role for population dynamics of the high alpine plant Geum reptans. Reproduction by seeds acts as mechanism promoting not only genetic diversity and dispersal but also rapid population growth in favourable years. Clonal reproduction serves to ensure population increase by slow but continuous growth even under distinct environmental variability and unfavourable weather conditions. The relative importance of sexual and clonal reproduction is highly variable among populations of G. reptans. However, the observed variation could only be explained to a small degree by contrasting habitats. A higher frequency of clonal reproduction occurred in populations from high and low altitudes in comparison with intermediate populations. Taken together, my results suggest that variation in reproduction could either be attributed to individual plasticity in response to different habitat conditions or resulted from genetic differentiation among populations, probably partly random in nature. Plant size is suggested to be an additional factor influencing the relationship between sexual and clonal reproduction demonstrating a higher threshold size for investment in sexual reproduction. The outstanding importance of adult survival for the life-history of G. reptans highly exceeding the impact of reproduction demonstrates the significance of longevity and persistence for this pioneer species of glacier-forelands. In long-lived G. reptans, adult survivorship is expected to serve as a buffer against temporal variation in reproduction that may be particularly important in frequently disturbed alpine habitats. The importance of persistence and the ability for clonal growth balancing reduced seedling recruitment explain why, despite substantial seed losses, population growth of G. reptans might not be limited by predispersal seed predation. In G. reptans as a long-lived perennial clonal plant being most vulnerable to adult mortality, seed supply is of minor importance for population dynamics. In unpredictable habitats where successful recruitment by seeds may not occur every year, this might be an important adaptation. However, seed predation by reducing the proportion of viable seeds restricts successful colonisation of new sites, thereby contributing to the not very high frequency of this species in the alpine landscape and reducing geneflow among populations

Eine empirische Untersuchung zur Bestandsaufnahme in deutschen Großunternehmen und interkulturellen Trainingsinstitutionen

Mit dem Ziel, Informationen für eine umfassende Qualitätssicherung im interkulturellen Teamtrainingsbereich zu erlangen, wurde in den Monaten Juli bis August 2004 eine anonyme Online-Befragung durchgeführt, zu deren Teilnahme jeweils 100 deutschsprachige interkulturelle Teamtrainer und 100 Personalentwickler deutscher Großunternehmen eingeladen waren (Rücklaufquote 50% bzw. 56%). Nebenprodukt der dieser Untersuchung zugrunde liegenden Qualitätsuntersuchung ist ein umfassender Einblick sowohl in die Angebots- als auch in die Nachfragestruktur des interkulturellen Teamtrainingsbereichs in Deutschland. Der folgende Artikel fasst die Hauptergebnisse der Untersuchung knapp zusammen und zeichnet damit ein umfangreiches Bild der aktuellen Trainingssituation. Eine ausführlichere Darstellung der Untersuchungsergebnisse sowie eine tiefgreifendere Diskussion vor allem in Bezug auf das Thema Qualitätssicherung findet in diesem Artikel nicht statt, sondern wird in einer Dissertation am Lehrstuhl für Interkulturelle Kommunikation in der Wirtschaft bei Prof. Dr. Bolten abgehandelt

On the Path to Success for Indigenous Students: Utilizing Culturally Responsive Leadership Practices in Kindergarten to Grade 12 Schools

For many Indigenous students, education can be difficult as they are met with numerous barriers inhibiting their ability to connect and engage with the curriculum. Unfortunately, this is in large part due to the intergenerational legacy of Residential Schools. In order to begin to affect change on a school level, educational leaders play a significant role in fostering a school environment that is welcoming and accepting of Indigenous worldviews and epistemologies. In order to achieve this, researchers have identified that educational leaders who implement and support culturally responsive practices are more successful at supporting Indigenous students and helping them achieve greater success in educational settings. This capstone study provides a review of the literature related to culturally responsive leadership and teaching practices that can be utilized when working with Indigenous students. Implementation of these practices can be used to increase connection and engagement with the curriculum and help Indigenous students feel a sense of belonging and significance. Following the literature review, recommendations are provided outlining strategies educational leaders can use to increase their personal leadership capacity surrounding culturally responsive practices, as well as supporting teachers on this journey

Geopier Soil Reinforcement System – Case Histories of High Bearing Capacity Footing Support and Floor Slab Support

The Geopier® Rammed Aggregate Pier system is an innovative ground improvement method developed in the 1980’s that has grown in the United States and more recently in Asia and Europe, for supporting lightly to heavily loaded structures and highway and railroad embankments. The system is unique because it prestresses and prestrains adjacent matrix soils during installation of rammed aggregate piers. It has been successfully used on hundreds of project sites to support building foundations, floor slabs, storage tanks, and roadway embankments founded on both, poor and unsuitable soils as well as fair to good soils. The rammed aggregate pier system controls settlements effectively by reinforcing soils below structures and thus improving bearing capacities and allowable bearing pressures while controlling settlements. Two case histories of specialized applications are presented in this paper: (1) Wind tower projects in Germany, where the Geopier system provides high bearing capacity and overturning moment resistances to support the foundations in soft soils; and (2) Rammed Aggregate Pier soil reinforcement support of foundations and large area floor slab system for a commercial warehouse facility in the Philippines. This paper is of particular significance because it presents case histories of a relatively new soil improvement system tailored to increase foundation bearing capacities for dynamic footing loadings and provide positive settlement control for wide area loads including floor slabs. Design and implementation of the Geopier system are presented. Evaluations of the behavior of Geopier elements based on stiffness modulus test data and an analytical approach to compare modulus test results to the design assumptions are also discussed

Specimen records of benthic macroinvertebrate samples collected by Norman H. Anderson in the vicinity of Mount St. Helens, 1980-1990

A private collection of 903 vials containing mostly aquatic macroinvertebrates is presented from Dr. Norman Herbert Anderson, Professor of Entomology at Oregon State University from 1962-1995. The majority of these specimens were collected from multiple freshwater streams during his research at Mount St. Helens (WA, USA) soon after the May 18, 1980 eruption. This collection also includes 15 vials containing specimens collected by Luis A. Fusté from the Muddy River (WA, USA) on March 29, 1980, less than 2 months before the eruption. The vast majority of these vials include a label indicating the sampling location, the date collected, and taxonomic identification