Search

It is widely acknowledged that gender bias is pervasive in all levels of academia, affecting all women regardless of social identity (Llorens et al. [12]). These student projects illustrated how and why awareness on gender bias should not only be raised among publishing agencies, university authorities, or funding agencies, but also among the students themselves as they represent the future of science and academia. Research on gender balance in academia is important, she continues, not only to understand the magnitude of the imbalance and its pervasiveness, but also as an important tool for mentoring students and bringing awareness to future generations. Research on gender bias as a mentoring tool: Spreading awareness to the next generation of ec... Research on gender bias in ecology and biogeography can be used as a tool for mentoring young scientists. [Extracted from the article]

Natural history, loosely defined as the observational study of organisms in the habitats where they occur, is recognized at the roots of ecology. Although the centrality of natural history in ecology has shifted over time, natural history is currently in resurgence: many again consider it to be the foundation of ecological and evolutionary inquiry and advocate the value of organism‐centered approaches to address contemporary ecological challenges. Educators identify natural history as the foundational entryway into the practice of ecology, for example in the Ecological Society of America's Four‐Dimensional Ecology Education (4DEE) framework. A strong natural history foundation can help generate testable hypotheses to refine mechanistic understanding of the drivers regulating species distributions and abundances and to inform restoration and conservation efforts. Given the resurgence of natural history as the foundation for ecological knowledge and practice, it is important to recognize that natural history has a long history of racism that has impacted ecological thought and priorities. This history shapes not only who conducts ecological science but also foundational ecological concepts. For example, natural history's emphasis on pristine nature untouched by humans disregards or appropriates stewardship and knowledge of most of the world's population. Because of the legacy of chattel slavery, this exclusion is particularly strong for people of African descent. This exclusion narrows ecological inquiry, limits the capacity to find solutions to ecological problems, and risks interventions that perpetuate the relation between eugenics, ecological knowledge, and natural systems. If ecology is to become an inclusive, responsive, and resilient discipline, this knowledge gap must be addressed. We here present the colonial and racist underpinnings of natural history and offer strategies to expand inclusion in the study of nature. Natural history was steeped in racism, providing a hierarchy of cultures and a taxonomy of races. Complementing growing interest in traditional and Indigenous ecological knowledge, we focus on Black ecological knowledge, for example in the study of "maroon ecologies." Addressing the racist history of natural history is necessary for removing structural and racist barriers to diverse participation and expanding ecological knowledge bases in service of better and more just science. [ABSTRACT FROM AUTHOR]

Field experiences can provide transformative opportunities for many individuals who eventually pursue ecology, natural resource, and conservation careers. However, some of the same elements of field‐based programs that define and provide pivotal experiences for some represent barriers for others, especially students from underrepresented groups. Barriers may be financial, physical, cultural, or social. Issues of gender, identity, and race/ethnicity, for example, can be isolating or shut down learning during intensive field experiences when group leaders are not prepared to respond to interpersonal challenges. We explore some benefits and barriers presented by field learning experiences as well as some challenges and potential strategies to broaden inclusivity with the hope of encouraging further conversation on diversity and inclusion in field experiences. [ABSTRACT FROM AUTHOR]

Despite considerable efforts to enhance participation of underrepresented demographics, participation of scholars of color in STEM remains stagnant. In contrast to other academic disciplines, the experiences of STEM scholars of color are relatively unvoiced, which hinders examination of the factors that reduce participation and retention. Social science and education research reveal the importance of intersectional strategies to address institutional and cultural practices that reduce diverse participation. Institutional change requires the support of the STEM workforce. I summarize important issues that influence recruitment and retention and offer strategies that can improve recruitment and retention of faculty of color. Broad awareness among STEM practitioners of the relationship between race and the biases that reduce recruitment and retention of underrepresented scholars can support STEM diversity initiatives. [ABSTRACT FROM AUTHOR]

Perennial grasses are promising candidates for bioenergy crops, but species that can escape cultivation and establish self-sustaining naturalized populations (feral) may have the potential to become invasive. Fertile Miscanthus × giganteus, known as 'PowerCane,' is a new potential biofuel crop. Its parent species are ornamental, non-native Miscanthus species that establish feral populations and are sometimes invasive in the USA. As a first step toward assessing the potential for 'PowerCane' to become invasive, we documented its growth and fecundity relative to one of its parent species ( Miscanthus sinensis) in competition with native and invasive grasses in common garden experiments located in Columbus, Ohio and Ames, Iowa, within the targeted range of biofuel cultivation. We conducted a 2-year experiment to compare growth and reproduction among three Miscanthus biotypes-'PowerCane,' ornamental M. sinensis, and feral M. sinensis-at two locations. Single Miscanthus plants were subjected to competition with a native grass ( Panicum virgatum), a weedy grass ( Bromus inermis), or no competition. Response variables were aboveground biomass, number of shoots, basal area, and seed set. In Iowa, all Miscanthus plants died after the first winter, which was unusually cold, so no further results are reported from the Iowa site. In Ohio, we found significant differences among biotypes in growth and fecundity, as well as significant effects of competition. Interactions between these treatments were not significant. 'PowerCane' performed as well or better than ornamental or feral M. sinensis in vegetative traits, but had much lower seed production, perhaps due to pollen limitation. In general, ornamental M. sinensis performed somewhat better than feral M. sinensis. Our findings suggest that feral populations of 'PowerCane' could become established adjacent to biofuel production areas. Fertile Miscanthus × giganteus should be studied further to assess its potential to spread via seed production in large, sexually compatible populations. [ABSTRACT FROM AUTHOR]

The perennial grass genus Miscanthus has great promise as biomass feedstock, but there are concerns about potential invasion outside production fields. While the sterile hybrid Miscanthus × giganteus is currently one of the leading feedstock options due to its low invasive potential, fertile varieties are being developed to reduce establishment costs, and their invasive risks need to be further assessed. We performed seed addition experiments in Ohio and Iowa, USA to examine the establishment, flowering, persistence, and shoot biomass per plot of a fertile M. × giganteus biotype ('PowerCane') and two Miscanthus sinensis biotypes, one feral, and one ornamental. Seeds were added to small, replicated plots in each of the 2 years under two seeding densities and two competition treatments, and plots were monitored for 2-3 years. The 'PowerCane' biotype established better, survived better, and produced greater amounts of biomass per plot than both M. sinensis biotypes. All three biotypes flowered by the second or third year after establishment, with inflorescences more numerous in 'PowerCane' and the Ornamental M. sinensis biotypes. Effects of seeding density and competition on these patterns were minor in most cases. Our research suggests that 'PowerCane' exhibits many traits shared by both biomass crops and invasive species: multi-year persistence, high biomass potential, and fertility. We suggest that the benefits of a seeded M. × giganteus should be carefully weighed against its increased invasive risk prior to deployment across the landscape. [ABSTRACT FROM AUTHOR]

Clonality is a widespread life history trait in flowering plants that may be essential for population persistence, especially in environments where sexual reproduction is unpredictable. Frequent clonal reproduction, however, could hinder sexual reproduction by spatially aggregating ramets that compete with seedlings and reduce inter-genet pollination. Nevertheless, the role of clonality in relation to variable sexual reproduction in population dynamics is often overlooked. We combined population matrix models and pollination experiments to compare the demographic contributions of clonal and sexual reproduction in three Dicentra canadensis populations, one in a well-forested landscape and two in isolated forest remnants. We constructed stage-based transition matrices from 3 years of census data to evaluate annual population growth rates, λ. We used loop analysis to evaluate the relative contribution of different reproductive pathways to λ. Despite strong temporal and spatial variation in seed set, populations generally showed stable growth rates. Although we detected some pollen limitation of seed set, manipulative pollination treatments did not affect population growth rates. Clonal reproduction contributed significantly more than sexual reproduction to population growth in the forest remnants. Only at the well-forested site did sexual reproduction contribute as much as clonal reproduction to population growth. Flowering plants were more likely to transition to a smaller size class with reduced reproductive potential in the following year than similarly sized nonflowering plants, suggesting energy trade-offs between sexual and clonal reproduction at the individual level. Seed production had negligible effects on growth and tuber production of individual plants. Our results demonstrate that clonal reproduction is vital for population persistence in a system where sexual reproduction is unpredictable. The bias toward clonality may be driven by low fitness returns for resource investment in sexual reproduction at the individual level. However, chronic failure in sexual reproduction may exacerbate the imbalance between sexual and clonal reproduction and eventually lead to irreversible loss of sex in the population. [ABSTRACT FROM AUTHOR]

Gene flow in crop-wild complexes between phenotypically differentiated ancestors may transfer adaptive genetic variation that alters the fecundity and, potentially, the population growth ( λ) of weeds. We created biotypes with potentially invasive traits, early flowering or long leaves, in wild radish ( Raphanus raphanistrum) and F5 crop-wild hybrid ( R. sativus × R. raphanistrum) backgrounds and compared them to randomly mated populations, to provide the first experimental estimate of long-term fitness consequences of weedy life-history variation. Using a life table response experiment design, we modeled λ of experimental, field populations in Pellston, MI, and assessed the relative success of alternative weed strategies and the contributions of individual vital rates (germination, survival, seed production) to differences in λ among experimental populations. Growth rates ( λ) were most influenced by seed production, a trait altered by hybridization and selection, compared to other vital rates. More seeds were produced by wild than hybrid populations and by long-leafed than early-flowering lineages. Although we did not detect a biotype by selection treatment effect on lambda, lineages also exhibited contrasting germination and survival strategies. Identifying life-history traits affecting population growth contributes to our understanding of which portions of the crop genome are most likely to introgress into weed populations. [ABSTRACT FROM AUTHOR]

Recent elevated temperatures and prolonged droughts in many already water-limited regions throughout the world, including the southwestern United States, are likely to intensify according to future climate-model projections. This warming and drying can negatively affect perennial vegetation and lead to the degradation of ecosystem properties., To better understand these detrimental effects, we formulate a conceptual model of dryland ecosystem vulnerability to climate change that integrates hypotheses on how plant species will respond to increases in temperature and drought, including how plant responses to climate are modified by landscape, soil and plant attributes that are integral to water availability and use. We test the model through a synthesis of fifty years of repeat measurements of perennial plant species cover in large permanent plots across the Mojave Desert, one of the most water-limited ecosystems in North America., Plant species ranged in their sensitivity to precipitation in different seasons, capacity to increase in cover with high precipitation and resistance to decrease in cover with low precipitation., Our model successfully explains how plant responses to climate are modified by biophysical attributes in the Mojave Desert. For example, deep-rooted plants were not as vulnerable to drought on soils that allowed for deep-water percolation, whereas shallow-rooted plants were better buffered from drought on soils that promoted water retention near the surface., Synthesis. Our results emphasize the importance of understanding climate-vegetation relationships in the context of biophysical attributes that influence water availability and provide an important forecast of climate-change effects, including plant mortality and land degradation in dryland regions throughout the world. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Question: We present a study of positive and negative interactions between the invasive grass Schismus barbatus (Poaceae) and Ambrosia dumosa (Asteraceae). Ambrosia facilitates seedling establishment, and such facilitation may accelerate invasion of exotic species, which, in turn, may reduce establishment of native plants. Location: Joshua Tree National Park, California, USA. Methods: During 2003-2004, we used field surveys to characterize the natural spatial distribution of Schismus in relation to native shrubs, and experimentally manipulated seed rain of Ambrosia and Schismus at three distances from adult Ambrosia canopies. We measured percentage germination and individual performance of both species. Field data were complemented by a greenhouse experiment that measured competition between Ambrosia seedlings and Schismus planted at three densities and five relative abundances under controlled conditions. Results: Field surveys showed that the density of Schismus is independent of Ambrosia shrubs, but growth is enhanced near shrub canopies. In our field experiment Schismus is facilitated by adult Ambrosia. Under controlled conditions, Schismus does not respond to the density of Ambrosia seedlings, but changes in density of Schismus decreased performance of Ambrosia seedlings. Conclusion: Schismus invasion may be detrimental to native perennial plant populations. Although a reduction of seedling establishment is not usually expected to slow population growth of long-lived perennials, recent unprecedented adult mortality in this community, and the well-documented facilitative role of Ambrosia, suggest that Schismus invasion may be of high ecological significance. [ABSTRACT FROM AUTHOR]

I present results from analyses of 20 years of spatiotemporal dynamics in a desert perennial community. Plants were identified and mapped in a 1-ha permanent plot in Joshua Tree National Park (California, USA) in 1984. Plant size, mortality, and new seedlings were censused every five years through 2004. Two species, Ambrosia dumosa and Tetracoccus hallii, were dominant based on their relative abundance and ubiquitous distributions. Spatial analysis for distance indices (SADIE) identified regions of significantly high (patches) or low (gaps) densities. I used SADIE to test for (1) transience in the distribution of patches and gaps within species over time and (2) changes in juvenile—adult associations with conspecific adults and adults of the two dominant species over time. Plant performance was quantified in patches and gaps to determine plant responsiveness to local spatial associations. Species identity was found to influence associations between juveniles and adults. Juveniles of all species showed significant positive spatial associations with the dominant A. dumosa but not with T. hallii. The broad distribution of A. dumosa may increase the spatial extent of non- dominant species that are facilitated by this dominant. The spatial location of patches and gaps was generally consistent over time for adults but not juveniles. Observed variability in the locations of juvenile patches and gaps suggested that suitable locations for establishment were broad relative to occupied regions of the habitat, and that conditions for seed germination were independent of conditions for seedling survival. A dramatic change in spatial distributions and associations within and between species occurred after a major drought that influenced data from the final census. Positive associations between juveniles and adults of all species were found independent of previous associations and most species distributions contracted to areas that were previously characterized by low density. By linking performance to spatial distribution, results from this study offer a spatial context for plant—plant interactions within and among species. Community composition could be influenced both by individual species tolerances of abiotic conditions and by the competitive or facilitative interactions individuals exert over neighbors. [ABSTRACT FROM AUTHOR]

Extreme events shape population and community trajectories. We report episodic mortality across common species of thousands of long-lived perennials individually tagged and monitored for 20 years in the Colorado Desert of California following severe regional drought. Demographic records from 1984 to 2004 show 15 years of virtual stasis in populations of adult shrubs and cacti, punctuated by a 55–100% die-off of six of the seven most common perennial species. In this episode, adults that experienced reduced growth in a lesser drought during 1984–1989 failed to survive the drought of 2002. The significance of this event is potentially profound because population dynamics of long-lived plants can be far more strongly affected by deaths of adults, which in deserts potentially live for centuries, than by seedling births or deaths. Differential mortality and rates of recovery during and after extreme climatic events quite likely determine the species composition of plant and associated animal communities for at least decades. The die-off recorded in this closely monitored community provides a unique window into the mechanics of this process of species decline and replacement. [ABSTRACT FROM AUTHOR]

1 Spatiotemporal responses to habitat conditions are important components of plant population and community dynamics. Plant stage or size is a common predictor of plant performance for a range of ecological conditions, including responses to neighbours. Plant response to local conditions varies from seedling establishment through to senescence, with strong implications for population regulation. 2 I investigated size-dependent responses to near adult neighbours among a uniquely quantitative sample of mapped juvenile and adult bur-sage ( Ambrosia dumosa), a common shrub in the Colorado Desert of California. 3 Analyses of juvenile establishment and survival for two 5-year census periods from 1984 to 1989 and 1989 to 1994 determined that germination and survival was greater for juveniles located under adults compared with away from adults. However, analyses of neighbour effects on growth of plants from the 1984 cohort showed that near adult neighbours improved juvenile growth over the 10-year interval from 1984 to 1994, but reduced adult growth. 4 A size-dependent, ontogenetic shift occurs because neighbouring adult plants significantly improve the demographic performance of juveniles, but diminish that of larger established plants. 5 The ontogenetic niche shift may be a useful framework to describe such differential responses of juvenile and adult plants. The utility of this framework is that responses to spatial and temporal variability in the environment are clearly demonstrated through ontogenetic constraints on plant performance, which provide an alternative mechanism of coexistence within and between species. [ABSTRACT FROM AUTHOR]

A profusion of fruit forms implies that seed dispersal plays a central role in plant ecology, yet the chance that an individual seed will ultimately produce a reproductive adult is low to infinitesimal. Extremely high variance in survival implies that variations in fruit production or transitions from seed to seedling will contribute little to population growth. The key issue is that variance in survival of plant life-history stages, and therefore the importance of dispersal, differs greatly among and within plant communities. In stable communities of a few species of long-lived plants, variances in seed and seedling survival are immense, so seed-to-seedling transitions have little influence on overall population dynamics. However, when seedlings in different circumstances have very different chances of survival--in ecological succession, for example, or when dispersed seeds escape density-dependent mortality near parent trees--the biased survival of dispersed seeds or seedlings in some places rather than others results in pervasive demographic impacts. [ABSTRACT FROM AUTHOR]

Examines the influence of neighboring plants on the demography of perennial shrub Ambrosia dumosa in Colorado Desert, California. Effects of neighboring plants on plant growth and survival; Documentation of differences in population growth, elasticity structure and stable size; Contributions of patch types on overall population dynamics.

Spatial pattern and patterns of mortality were analyzed from a five year re-census of over 7000 mapped perennial shrubs within a one hectare study plot in Joshua Tree National Park. A five year interval revealed evidence for negative intraspecific interactions which was not evident after a one year evaluation of the same plants within the study area. Juvenile mortality was a positive function of conspecific density for Ambrosia dumosa, Eriogonum fasciculatum and Sphaeralcea ambigua. In addition, juvenile E. fasciculatum that died occurred closer to conspecific adults than would be expected by chance. The two censuses are similar in that uniform patterns of distribution among conspecifics are rare, particularly for non-succulent species. These results emphasize the value of mapped study sites in allowing dynamic inferences from otherwise static analyses. Herbivory and nurse effects are implicated as potential factors influencing the dispersion of perennial plants within deserts. [ABSTRACT FROM AUTHOR]

Science, technology, engineering, and math (STEM) disciplines suffer from chronically low participation of women and underrepresented minorities. Diversity enhancement initiatives frequently attempt to mitigate skill deficits such as math skills in an attempt to improve preparedness of these students. However, such interventions do not address cultural or social barriers that contribute to the isolation and marginalization that discourage continued participation in STEM. Science exists and is developed within social constructs.; because of this, cultural conflicts can occur pertaining to contrasting cultural belief systems between educators and students, or to socially-biased perspectives that are embedded in disciplinary values. These conflicts are implicated in the low recruitment and retention of underrepresented students in STEM. To address the relationship between culture and STEM diversity, I present a case study that examines the role of culturally-biased views of nature on the lack of diverse participation in ecology and environmental biology. I conclude by advocating the use of inclusive, culturally-sensitive teaching practices that can improve the climate for underrepresented students and increase diverse recruitment and retention in STEM. [ABSTRACT FROM AUTHOR]

Long‐term species persistence in plant communities is contingent in part on the conditions that favor establishment and early survival. In stressful habitats, facilitated seedling establishment can enhance species richness by providing a safe‐site for species unable to establish in open microsites. However, the indirect effects of seedling competition may drive persistence in locations where seedlings occur in high density. This under‐examined dynamic can influence community recovery to stress by favoring competitively dominant species, in particular when stress increases local seedling density in favorable microsites. We present the results of a response surface experiment that examines growth responses among seedlings of Ambrosia dumosa, Eriogonum fasciculatum, and Larrea tridentata that were planted at three densities and four relative frequencies. These species co‐occur at an extensively monitored reference community located in the Colorado Desert, California, USA, where extensive drought caused unprecedented mortality that will require novel recruitment for the community to reach pre‐disturbance composition. Significant, non‐hierarchical competitive responses show that seedling survival is contingent on the species identity and density of neighboring seedlings. This result supports non‐hierarchical competition among these common species. Ambrosia and Eriogonum had faster growth rates than Larrea, but also experienced larger reductions in growth from competition than Larrea. Although drought may intensify seedling competition in favorable locations, the context dependency of competitive outcomes may permit coexistence. [ABSTRACT FROM AUTHOR]

Seed dispersal enables plants to reach hospitable germination sites and escape natural enemies. Understanding when and how much seed dispersal matters to plant fitness is critical for understanding plant population and community dynamics. At the same time, the complexity of factors that determine if a seed will be successfully dispersed and subsequently develop into a reproductive plant is daunting. Quantifying all factors that may influence seed dispersal effectiveness for any potential seed-vector relationship would require an unrealistically large amount of time, materials and financial resources. On the other hand, being able to make dispersal predictions is critical for predicting whether single species and entire ecosystems will be resilient to global change. Building on current frameworks, we here posit that seed dispersal ecology should adopt plant functional groups as analytical units to reduce this complexity to manageable levels. Functional groups can be used to distinguish, for their constituent species, whether it matters (i) if seeds are dispersed, (ii) into what context they are dispersed and (iii) what vectors disperse them. To avoid overgeneralization, we propose that the utility of these functional groups may be assessed by generating predictions based on the groups and then testing those predictions against species-specific data. We suggest that data collection and analysis can then be guided by robust functional group definitions. Generalizing across similar species in this way could help us to better understand the population and community dynamics of plants and tackle the complexity of seed dispersal as well as its disruption. [ABSTRACT FROM AUTHOR]