Global change is altering patterns of community assembly, with net outcomes dependent on species’ responses to the environment, both directly and mediated through biotic interactions. Here, we assess alpine plant community responses in a 15-year factorial nitrogen addition, warming and snow manipulation experiment. We used a dynamic competition model to estimate the density-dependent and independent processes underlying changes in species-group abundances over time. Density-dependent shifts in competitive interactions drove long-term changes in abundance of species-groups under global change. Density-independent processes were important when counteracting environmental drivers limited the growth response of the dominant species. Furthermore, competitive interactions shifted with environmental change, primarily with nitrogen, and drove non-linear abundance responses across environmental gradients. Our results highlight that global change can either reshuffle species hierarchies or further favor already dominant species; predicting which outcome will occur requires incorporating both density-dependent and independent mechanisms and how they interact across multiple global change factors.
The success of invasive plants is influenced by many interacting factors, but evaluating multiple possible mechanisms of invasion success and elucidating the relative importance of abiotic and biotic drivers is challenging, and therefore rarely achieved. We used live, sterile or inoculated soil from different soil origins (native range and introduced range plantation; and invaded plots spanning three different countries) in a fully factorial design to simultaneously examine the influence of soil origin and soil abiotic and biotic factors on the growth of invasive Pinus contorta. Our results displayed significant context dependency in that certain soil abiotic conditions in the introduced ranges (soil nitrogen, phosphorus or carbon content) influenced responses to inoculation treatments. Our findings do not support the enemy release hypothesis or the enhanced mutualism hypothesis, as biota from native and plantation ranges promoted growth similarly. Instead, our results support the missed mutualism hypothesis, as biota from invasive ranges were the least beneficial for seedling growth. Our study provides a novel perspective on how variation in soil abiotic factors can influence plant-soil feedbacks for an invasive tree across broad biogeographical contexts.
Ethiopian dry Afromontane forests are complex ecosystems that have important economic and ecological roles. However, recurrent fire has been a source of disturbance for these forests. We assessed the effect of fire on soil fungal communities in a remnant dry Afromontane forest in Wondo Genet, southern Ethiopia, by analysing soil samples collected from unburned stands and from stands one and ten years after fire using DNA metabarcoding of the ITS2 rDNA. The analysis indicated that the soil fungal community was most diverse soon after a fire disturbance and declined over time. Fungal community composition also differed among stands. Our results also indicated that differences in fungal diversity were stand dependent rather than due to the chronology of the fire history in this forest system. We found higher numbers of mycorrhizal species in burned stands, suggesting that these fungal symbionts could compensate for the effects of nutrient stress caused by fire in these areas. Fungal community composition was also significantly correlated with organic matter content, potassium and magnesium in soil. This work could be considered as a case study since the plots were established in a single stand for each treatment in the dry Afromontane forests of Ethiopia. Thus, we recommend further studies and conclusions regarding other stands need to be taken with caution.
Regardless of how soil is defined, soils are the most diverse of all ecosystems. It is estimated that 25–30% of all species on Earth live in soils for all or part of their lives (Decaëns et al. 2006). A single gram of soil is estimated to contain 1 × 109 microorganisms, roughly the same population size as the number of humans in Africa (Microbiology by Numbers 2011). That same gram of soil likely contains 4000 species. They are only one part of a larger food web, however, that includes roundworms (phylum Nematoda), springtails (order Collembola), and other fauna (Fig. 5.1). The soil fauna has equally astounding numbers (e.g., 40,000 springtails in 1 m2). Soil organisms, ranging from microbes to moles (family Talpidae), promote crop growth and livestock production (Barrios 2007; Kibblewhite et al. 2008), produce antibiotics (Wall et al. 2015), control nutrient loads in surface soils and groundwater (De Vries et al. 2011), and regulate greenhouse gas emissions (Singh et al. 2010).
Managers use restorative fire and thinning for ecological benefits and to convert fuel-heavy forests to fuel-lean landscapes that lessen the threat of stand-replacing wildfire. In this study, we evaluated the long-term impact of thinning and prescribed fire on soil biochemistry and the mycorrhizal fungi associated with ponderosa pine (Pinus ponderosa). Study sites were located in the Blue Mountains of northeastern Oregon where prescribed fire treatments implemented in 1998 and thinning treatments in 2000 included prescribed fire, mechanical thinning of forested areas, a combination of thinning followed by fire, and an untreated control. Soil sampling for this study occurred in 2014 and included four replications of each treatment for a total of 16 experimental units. Differences among treatments in Bray-P, total C and N, and pH were likely driven by the thinning treatments and the resultant deposition of residual slash following harvesting or the consumption of slash by prescribed fire. Similar litter depths across treatments suggest that litter depth stabilizes over time in these forests. After more than a decade of recovery, mycorrhizal fungi in dry inland forests dominated by ponderosa pine that were subjected to fire returned to levels similar to the untreated controls. The results of this study demonstrate the resiliency of these forests to disturbances associated with restoration treatments, providing managers increased flexibility if maintaining abundant and persistent fungal communities for healthy soils is an objective.
The Biodiversity Heritage Library (BHL) is a global collaborative established in 2006, with a mission to improve research methodology by making biodiversity literature openly available.. The purpose of this poster is to describe three recent grant-funded endeavors to improve BHL. The National Digital Stewardship Residency (NDSR) project, Foundations to Actions: Extending Innovations in Digital Libraries in Partnership with NDSR Learners has 5 geographically distributed partners, each mentoring a resident. The goal is to plan a next-generation digital library and tools based on user priorities, using BHL as a test-bed for incorporating transcriptions, image searching, collection analysis and connections among museums, archives and biodiversity databases. Expanding Access to Biodiversity Literature positions BHL as an on-ramp to the national digital library infrastructure, the Digital Public Library of America (DPLA). Partners provide tools, support, including training, copyright permissions and dollars, to enable small content providers to contribute via BHL to DPLA. Finally, Zooniverse (which builds and hosts citizen science projects) developed Science Gossip as an investigation into the communication of science by images in both the Victorian period and today. Images in BHL are tagged using crowdsourcing, for better access and a better understanding of the range of individuals who established early science.
........................................................................................................................................................ 7 Objectives ..................................................................................................................................................... 8 Background ................................................................................................................................................... 8 Materials and Methods ................................................................................................................................ 10 Study Area .............................................................................................................................................. 10 Experimental Design ............................................................................................................................... 11 Plot establishment and re-establishment ................................................................................................. 13 Soil Sampling .......................................................................................................................................... 13 Soil Chemistry Analysis ......................................................................................................................... 13 Fine Root Processing of Mycorrhizas ..................................................................................................... 14 Molecular Analysis ................................................................................................................................. 14 Statistical Analysis .................................................................................................................................. 14 Results and Discussion ............................................................................................................................... 15 Project Overview .................................................................................................................................... 15 Soil Physical Properties .......................................................................................................................... 16 Soil Chemical Properties ......................................................................................................................... 17 EMF Communities .................................................................................................................................. 19 Conclusions and Implications for Management .......................................................................................... 25 Literature Cited ........................................................................................................................................... 27 Appendix A: Contact Information for Key Project Personnel .................................................................... 34 Appendix B: Deliverables ........................................................................................................................... 35
Recent decades have seen the emergence of collaborative organizations for forest governance in landscape-scale management. A collaborative is defined as an organized collection of landowners, stakeholders, resource agencies, tribes, or other organizations that come together to address common issues and resolve problems through deliberation, consensus building, and cooperative learning (Goldstein and Butler 2010). Collaboratives are designed to be transparent, diverse, and inclusive (Wondolleck and Yaffee 2003). Although some collaboratives are community driven or place based, with the goal of protecting local interests or access, others are sparked by land managers who seek integrated solutions to multiple interests and objectives.
Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. In this study, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned "red" soil and less severely burned "black" soil from a burned forest on the eastern slope of the Cascade Range in Oregon. Specifically, we examined the effects of burn severity on soil nutrients and microbial communities for 1-4 years after wildfire. Soil nutrients were significantly reduced in red soils. Soil fungi and bacteria, assessed with molecular methods, steadily colonized both burn severities and soil biodiversity increased throughout the study showing that microbial communities seem to have the capacity to quickly adjust to extreme disturbances. Although richness did not vary by soil type, the fungal and bacterial community compositions varied with burn severity. This difference was greatest in the early time points following the fire and decreased with time. However, nutrient-limited conditions of red soils were detected for four years after the wildfire and raise concern about soil productivity at these sites. Published by Elsevier B.V.
Environmental change and long-term fire management in the western United States have created conditions that facilitate high-intensity burn areas in forested systems. Such burns may have dramatic effects on the soil microbial communities. In this study, we utilized experimental infrastructure in the Pringle Falls Experimental Forest in Oregon, where ten pairs of sites were assigned to either high burn (HB) or low burn (LB) intensity treatments to examine fungal community responses. In these treatments, understory shrubs and logging debris were masticated and broadcast burned (LB) or piled logs were fully combusted (HB) in a paired design. The burn treatments generated soil temperatures of similar to 100 degrees C (LB) or up to 700 degrees C (HB) at the soil surface. We sampled soils (0-10 cm) one week before and three weeks after ignition and Illumina MiSeq-analyzed fungal Internal Transcribed Spacer 1 (ITS1) PCR-amplicons to deeply dissect the fungal communities. Our data indicate dramatic and rapid responses in community diversity and evenness in the HB treatment, with similar responses, but to a lesser degree, in the LB treatment. Nonmetric Multidimensional Scaling (NMS) ordinations and analyses of taxon frequencies reveal a substantial community turnover and corresponding replacement of the dominant basidiomycetes by ascomycetes in the HB treatment. Similar trends were visible, but weaker in the LB treatments. These coarse-level taxonomic responses were attributable to a few fire-responsive fungi, particularly Operational Taxonomic Units (OTUs) assigned to Pyronema sp. and Morchella sp., whose frequencies increased more than 100-fold following the HB treatment. Our study highlights the strong and rapid fungal fire responses and differences among fires of different intensities. As the high intensity fires - such as those represented here by the HB treatment - tend to be spatially confined and limited in scale, we emphasize their potential to generate distinct patches that may substantially contribute to beta diversity on small scales. Further, these data lead to questions about fungal community recovery (return to community state preceding the fire) and the importance of patch dynamics following a fire as well as function of post-fire communities and ecosystem services that they may provide. (C) 2016 Elsevier B.V. All rights reserved.
Fuel accumulation and climate shifts are predicted to increase the frequency of high-severity fires in ponderosa pine (Pinus ponderosa) forests of central Oregon. The combustion of fuels containing large downed wood can result in intense soil heating, alteration of soil properties, and mortality of microbes. Previous studies show ectomycorrhizal fungi (EMF) improve ponderosa seedling establishment after fire but did not compare EMF communities at different levels of soil burn intensity in a field setting. For this study, soil burn intensity effects on nutrients and EMF communities were compared at Pringle Falls Experimental Forest, La Pine, Oregon. Twelve replicate sites were used, each with three treatments: high intensity soil burn from large downed wood combustion (HB), low intensity soil burn (LB), and unburned control (UB). Temperatures lethal to fungi were detected at 0-cm, 5-cm, and 10-cm depths in HB soils and 0-cm depth in LB soils. Ponderosa pine seedlings planted post-burn were harvested after four months for EMF root tip analysis. We found: (a) greater differences in soil properties and nutrients in HB soils compared to LB and UB soils; (b) no differences in EMF richness and diversity among treatments; (c) weak differences in community composition based on relative abundance between UB and either burn treatments; and (d) EMF composition in HB and LB treatments correlated with soil carbon and organic matter contents. These results support the hypothesis that the combustion of large downed wood can alter the soil environment directly beneath it. However, an EMF community similar to LB soils recolonized HB soils within one growing season. Community results from both burn treatments suggest an increase in patchy spatial distribution of EMF. We hypothesize that quick initiation of EMF recolonization is possible depending on the size of high intensity burn patches, proximity of low and unburned soil, and survival of nearby hosts. The importance of incorporating mixed fire effects in fuel management practices will help to provide EMF refugia for ponderosa pine forest regeneration. (C) Published by Elsevier B.V.
Forest ecosystems of the Pacific Northwest of the USA are changing as a result of climate change. Specifically, rise of global temperatures, decline of winter precipitation, earlier loss of snowpack, and increased summer drought are altering the range of Pinus contorta. Simultaneously, flux in environmental conditions within the historic P. contorta range may facilitate the encroachment of P. ponderosa into P. contorta territory. Furthermore, successful pine species migration may be constrained by the distribution or co-migration of ectomycorrhizal fungi (EMF). Knowledge of the linkages among soil fungal diversity, community structure, and environmental factors is critical to understanding the organization and stability of pine ecosystems. The objectives of this study were to establish a foundational knowledge of the EMF communities of P. ponderosa and P. contorta in the Deschutes National Forest, OR, USA, and to examine soil characteristics associated with community composition. We examined EMF root tips of P. ponderosa and P. contorta in soil cores and conducted soil chemistry analysis for P. ponderosa cores. Results indicate that Cenococcum geophilum, Rhizopogon salebrosus, and Inocybe flocculosa were dominant in both P. contorta and P. ponderosa soil cores. Rhizopogon spp. were ubiquitous in P. ponderosa cores. There was no significant difference in the species composition of EMF communities of P. ponderosa and P. contorta. Ordination analysis of P. ponderosa soils suggested that soil pH, plant-available phosphorus (Bray), total phosphorus (P), carbon (C), mineralizable nitrogen (N), ammonium (NH4), and nitrate (NO3) are driving EMF community composition in P. ponderosa stands. We found a significant linear relationship between EMF species richness and mineralizable N. In conclusion, P. ponderosa and P. contorta, within the Deschutes National Forest, share the same dominant EMF species, which implies that P. ponderosa may be able to successfully establish within the historic P. contorta range and dominant EMF assemblages may be conserved.
We assessed the nutritional strategy of true morels (genus Morchella) collected in 2003 and 2004 in Oregon and Alaska, 1 or 2 y after forest fires. We hypothesized that the patterns of stable isotopes (δ(13)C and δ(15)N) in the sporocarps would match those of saprotrophic fungi and that radiocarbon (Δ(14)C) analyses would indicate that Morchella was assimilating old carbon not current-year photosynthate. We compared radiocarbon and stable isotopes in Morchella with values from concurrently collected foliage, the ectomycorrhizal Geopyxis carbonaria (Alb. & Schwein.) Sacc., the saprotrophic Plicaria endocarpoides (Berk.) Rifai, and with literature to determine isotopic values for ectomycorrhizal or saprotrophic fungi. Geopyxis, Plicaria and Morchella, respectively, were 3‰, 5‰ and 6‰ higher in 13C than foliage and 5‰, 7‰ and 7‰ higher in (15)N. High (15)N enrichment in Morchella indicated that recent litter was not the primary source for Morchella nitrogen, and similar (13)C and (15)N enrichments to Plicaria suggest that Morchella assimilates its carbon and nitrogen from the same source pool as this saprotrophic fungus. From radiocarbon analyses Morchella averaged 11 ± 6 y old (n = 19), Plicaria averaged 17 ± 5 y old (n = 3), foliage averaged 1 ± 2 y old (n = 8) and Geopyxis (n = 1) resembled foliage in Δ(14)C. We conclude that morels fruiting in post-fire environments in our study assimilated old carbon and were saprotrophic.
The environmental effect of extreme soil heating, such as occurs with the complete combustion of large downed wood during wildfires, is a post-fire management concern to forest managers. To address this knowledge gap, we stacked logs to create ‘mega-log’ burning conditions and compared the temperature, duration and penetration of the soil heat pulse in nine high intensity burned (HB) plots paired with adjacent masticated and broadcast burned low intensity burned (LB) plots at different soil depths (0, 5, 10 and 30 cm) in a Pinus ponderosa stand with volcanic pumice soils. Maximum soil surface temperatures ranges were 424–1168°C with a mean and standard error of 759 ± 9°C in the HB treatment and 42–360°C (107 ± 43°C) in the LB treatment. In the HB treatment, temperatures causing fine root and soil organism mortality (>60°C) penetrated the soil to at least 10 cm, but were not recorded at 30 cm. In the HB treatment, mean duration above 60°C at 0–10 cm persisted for 4–13 h (7.61 ± 1.02 h). Soils in the LB treatment experienced lethal temperatures at the surface for about an hour (1.19 ± 0.70 h) and at 5 cm were mostly well below lethal temperatures with the exception of one at 57°C and another at 100°C that remained above 60°C for 1.4 h. Large areas of high burn severity may affect long-term forest productivity. Our quantification of soil heating establishes conditions for ongoing studies investigating the effects of soil burn severity on tree seedling growth, soil fungi and nutrients.
This chapter presents a brief history, politics and geography of consumption, told through garments. The chapter explores some changing meanings of notions of ‘care’ (for things; for people; for the environment) through the story of one woman’s century-long lifetime of buying, making, wearing and caring for clothes. Her changing wardrobe guides the story, with some light reference to research in the social sciences, history and geography. It concludes with a discussion of what can be learnt from the story about the pursuit of a more environmentally and socially sustainable system of fashion and clothing.