Annual secondary production of fungal and bacterial decomposers associated with standing and benthic litter of the freshwater emergent macrophyte, \u3ci\u3etypha angustifolia \u3c/i\u3e

Fungi and bacteria are significant decomposers of plants within wetlands, but annual secondary production investigations are lacking. Microbial carbon assimilation into biomass and CO2 mineralization may contribute considerably to wetland biogeochemical cycling and energy flow. Naturally-occurring Typha angustifolia detritus was collected to determine annual areal carbon flow through secondary decomposers. Two decay phases, standing-dead and benthic litter, were analyzed concurrently to determine fungal (14C-acetate incorporation) and bacterial (3H-leucine incorporation) production estimates. Gradual collapse of the 2004 cohort standing-dead stocks resulted in lowest litter biomass at study\u27s end while benthic detrital stocks displayed little biomass fluctuation. This study indicates significantly higher fungal production rates within standing litter compared to bacteria. A noteworthy increase in areal production and CO2 mineralization occurred in benthic litter-associated fungi and bacteria. These results provide evidence indicating considerable annual carbon flow from emergent litter to heterotrophic decomposers within both decay phases

Identifying Worldviews on Corporate Sustainability: A Content Analysis of Corporate Sustainability Reports

Companies commonly issue sustainability or corporate social responsibility (CSR) reports. This study seeks to understand worldviews of corporate sustainability, or the corporate message conveyed regarding what sustainability or CSR is and how to enact it. Content analysis of corporate sustainability reports is used to position each company report within stages of corporate sustainability. Results reveal that there are multiple coexisting worldviews of corporate sustainability, but the most dominant worldview is focused on the business case for sustainability, a position anchored in the weak sustainability paradigm. We contend that the business case and weak sustainability advanced in corporate sustainability reports and by the Global Reporting Initiative are poor representations of sustainability. Ecological embeddedness, or a locally responsive strategy that is sensitive to local ecosystems, may hold the key to improved ecological sensemaking, which in turn could lead to more mature levels of corporate sustainability worldviews that support strong sustainability and are rooted in environmental science. This must be supported by government regulation

Content Trends in Sustainable Business Education: An Analysis of Introductory Courses in the U.S.

Purpose – This study aims to identify the content in introductory business sustainability courses in the USA to determine the most frequently assigned reading material and its sustainability orientation. Design/methodology/approach – In total, 81 introductory sustainable business course syllabi reading lists were analyzed from 51 US colleges and universities. The study utilized frequency counts for authors and readings and R analysis of key words to classify readings along the sustainability spectrum. Findings – The study reveals the most frequently assigned authors and readings in US sustainable business courses (by program type) and places them along the sustainability spectrum from weak to strong. In total, 55 per cent of the top readings assigned in the sample advocate a weak sustainability paradigm, and 29 per cent of the top readings advocate a strong sustainability paradigm. Research limitations/implications – This study focused on reading lists of introductory courses in the USA; cases, videos and supplemental materials were excluded, and the study does not analyze non-US courses. Practical implications – The findings of this study can inform instructors of the most commonly assigned authors and readings and identify readings that align with weak sustainability and strong sustainability. Instructors are now able to select sustainable business readings consistent with peers and which advance a weak or strong sustainability orientation. Originality/value – This is the first research to identify the most commonly assigned authors and readings to aid in course planning. This is also the first research to guide instructors in identifying which readings represent weak versus strong sustainability

Managing for Resilience: Lessons from Ecology

Understanding and developing resilience is becoming increasingly important in business for both leaders and organizations. Resilient organizations can successfully navigate uncertainty and change. Resilience, however, is a poorly understood attribute. We thus turn to ecosystem resilience theory to understand the concept of resilience. We identify four lessons that can be adapted from management for ecological resilience to management for business resilience: 1) resilience can be positive or negative depending on the nature of the function it supports, 2) diversity of individuals, departments, flows of information, perspective, and other attributes contributes to resilience, 3) because we have imperfect knowledge about the timing and nature of a given disturbance and thus imperfect knowledge about the exact components of diversity that will promote resilience in the face of it, there is a benefit to preserving diversity, even if it reduces efficiency under static conditions, and 4) to the extent that disturbances are unavoidable, emphasis should be placed on low-level adaptability to support high-level resilience of function. In managing for resilience, the leader can apply these lessons both by promoting diversity (of functional redundancy and response diversity) throughout all levels of the organization and by focusing on development of flexibility, nimbleness, and adaptability. This work has led us to develop seven theoretical propositions on leadership for resilience that can spur further research to integrate ecology and business leadership perspectives

Managing for Resilience: Lessons from Ecology

Understanding and developing resilience is becoming increasingly important in business for both leaders and organizations. Resilient organizations can successfully navigate uncertainty and change. Resilience, however, is a poorly understood attribute. We thus turn to ecosystem resilience theory to understand the concept of resilience. We identify four lessons that can be adapted from management for ecological resilience to management for business resilience: 1) resilience can be positive or negative depending on the nature of the function it supports, 2) diversity of individuals, departments, flows of information, perspective, and other attributes contributes to resilience, 3) because we have imperfect knowledge about the timing and nature of a given disturbance and thus imperfect knowledge about the exact components of diversity that will promote resilience in the face of it, there is a benefit to preserving diversity, even if it reduces efficiency under static conditions, and 4) to the extent that disturbances are unavoidable, emphasis should be placed on low-level adaptability to support high-level resilience of function. In managing for resilience, the leader can apply these lessons both by promoting diversity (of functional redundancy and response diversity) throughout all levels of the organization and by focusing on development of flexibility, nimbleness, and adaptability. This work has led us to develop seven theoretical propositions on leadership for resilience that can spur further research to integrate ecology and business leadership perspectives

Examining the Effect of Biochar on Invasive Typha x glauca in a Greenhouse Experiment

Invasive species in the Great Lakes pose ecological, economic, and social dilemmas as they alter and diminish the quality of ecosystems. By dominating native plant communities through efficient uptake of excess nutrients, the hybrid cattail, Typha × glauca, reduces the plant diversity of Great Lakes coastal wetlands, homogenizing habitat for many species of fish, animals, and insects. This study investigated how biochar, a charcoal-like substance, affected biomass accumulation in hybrid cattails and native wetland plants. I conducted a greenhouse experiment by growing assemblages of native wetland plants, Typha × glauca, and a combination of both native species and hybrid cattails in separate buckets with a homogenized, sand-compost mixture containing 0%, 2.5%, and 5% biochar by weight for approximately fifty days. I found that biochar reduced the overall biomass of Typha × glauca when comparing the 2.5% and 5% biochar applications to the 0% application. Biochar was also found to change the phosphorus content in Typha × glauca, a nutrient which is often found in excess in wetlands due to agricultural pollution. This preliminary study provides evidence that biochar has the potential to reduce the biomass of Typha × glauca, therefore impeding its dominance in Great Lakes coastal wetlands

Exploring the symbiont diversity of ancient western redcedars: arbuscular mycorrhizal fungi of long-lived hosts

Arbuscular mycorrhizal fungi (AMF) are globally distributed, monophyletic root symbionts with ancient origins. Their contribution to carbon cycling and nutrient dynamics is ecologically important, given their obligate association with over 70% of vascular plant species. Current understanding of AMF species richness and community structure is based primarily on studies of grasses, herbs, and agricultural crops, typically in disturbed environments. Few studies have considered AMF interactions with long-lived woody perennial species in undisturbed ecosystems. Here we examined AMF communities associated with roots and soils of young, mature, and old western redcedar (Thuja plicata) at two sites in the old-growth temperate rainforests of British Columbia. Due to the unique biology of AMF, community richness and structure were assessed using a conservative, clade-based approach. We found 91 AMF OTUs across all samples, with significantly greater AMF richness in the southern site, but no differences in richness along the host chronosequence at either site. All host age classes harboured AMF communities that were overdispersed (more different to each other than expected by chance), with young tree communities most resembling old tree communities. A comparison with similar clade richness data obtained from the literature indicates that western redcedar AMF communities are as rich as those of grasses, tropical trees, and palms. Our examination of undisturbed temperate old growth rainforests suggests that priority effects, rather than succession, are an important aspect of AMF community assembly in this ecosystem

Long-lasting effects of land use history on soil fungal communities in second-growth tropical rain forests

Our understanding of the long-lasting effects of human land use on soil fungal communities in tropical forests is limited. Yet, over 70% of all remaining tropical forests are growing in former agricultural or logged areas. We investigated the relationship among land use history, biotic and abiotic factors, and soil fungal community composition and diversity in a second-growth tropical forest in Puerto Rico. We coupled high-throughput DNA sequencing with tree community and environmental data to determine whether land use history had an effect on soil fungal community descriptors. We also investigated the biotic and abiotic factors that underlie such differences and asked whether the relative importance of biotic (tree diversity, basal tree area, and litterfall biomass) and abiotic (soil type, pH, iron, and total carbon, water flow, and canopy openness) factors in structuring soil fungal communities differed according to land use history. We demonstrated long-lasting effects of land use history on soil fungal communities. At our research site, most of the explained variation in soil fungal composition (R2 = 18.6%), richness (R2 = 11.4%), and evenness (R2 = 10%) was associated with edaphic factors. Areas previously subject to both logging and farming had a soil fungal community with lower beta diversity and greater evenness of fungal operational taxonomic units (OTUs) than areas subject to light logging. Yet, fungal richness was similar between the two areas of historical land use. Together, these results suggest that fungal communities in disturbed areas are more homogeneous and diverse than in areas subject to light logging. Edaphic factors were the most strongly correlated with soil fungal composition, especially in areas subject to light logging, where soils are more heterogenous. High functional tree diversity in areas subject to both logging and farming led to stronger correlations between biotic factors and fungal composition than in areas subject to light logging. In contrast, fungal richness and evenness were more strongly correlated with biotic factors in areas of light logging, suggesting that these metrics might reflect long-term associations in old-growth forests. The large amount of unexplained variance in fungal composition suggests that these communities are structured by both stochastic and niche assemblage processes

Linking the community structure of arbuscular mycorrhizal fungi and plants: a story of interdependence?

Arbuscular mycorrhizal fungi (AMF) are crucial to plants and vice versa, but little is known about the factors linking the community structure of the two groups. We investigated the association between AMF and the plant community structure in the nearest neighborhood of Festuca brevipila in a semiarid grassland with steep environmental gradients, using high-throughput sequencing of the Glomeromycotina (former Glomeromycota). We focused on the Passenger, Driver and Habitat hypotheses: (i) plant communities drive AMF (passenger); (ii) AMF communities drive the plants (driver); (iii) the environment shapes both communities causing covariation. The null hypothesis is that the two assemblages are independent and this study offers a spatially explicit novel test of it in the field at multiple, small scales. The AMF community consisted of 71 operational taxonomic units, the plant community of 47 species. Spatial distance and spatial variation in the environment were the main determinants of the AMF community. The structure of the plant community around the focal plant was a poor predictor of AMF communities, also in terms of phylogenetic community structure. Some evidence supports the passenger hypothesis, but the relative roles of the factors structuring the two groups clearly differed, leading to an apparent decoupling of the two assemblages at the relatively small scale of this study. Community phylogenetic structure in AMF suggests an important role of within-assemblage interactions

Stressed out symbiotes:hypotheses for the influence of abiotic stress on arbuscular mycorrhizal fungi

Abiotic stress is a widespread threat to both plant and soil communities. Arbuscular mycorrhizal (AM) fungi can alleviate effects of abiotic stress by improving host plant stress tolerance, but the direct effects of abiotic stress on AM fungi are less well understood. We propose two hypotheses predicting how AM fungi will respond to abiotic stress. The stress exclusion hypothesis predicts that AM fungal abundance and diversity will decrease with persistent abiotic stress. The mycorrhizal stress adaptation hypothesis predicts that AM fungi will evolve in response to abiotic stress to maintain their fitness. We conclude that abiotic stress can have effects on AM fungi independent of the effects on the host plant. AM fungal communities will change in composition in response to abiotic stress, which may mean the loss of important individual species. This could alter feedbacks to the plant community and beyond. AM fungi will adapt to abiotic stress independent of their host plant. The adaptation of AM fungi to abiotic stress should allow the maintenance of the plant-AM fungal mutualism in the face of changing climates. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00442-016-3673-7) contains supplementary material, which is available to authorized users