Spatially Disjunct Effects of Co‐occurring Competition and Facilitation

Little is known of the co‐occurrence and implications of competitive and facilitative interactions within sites. Here we show spatially disjunct competition and facilitation at forest edges, with beneficial influences of trees on seedling growth via increased ectomycorrhizal infection apparent from 12 to 20 m while closer to trees seedling growth is negatively correlated with canopy closure. As a result, seedling growth is maximized at intermediate distances. Facilitative interactions were nonlinear: being within 15.7 m of a tree maximized seedling mycorrhizal infection; while competitive effects were correlated with canopy closure, which was related to distance and generally scales with density. These patterns result in a positive correlation of tree density and seedling growth at low densities of trees, and negative correlation at higher densities because of competition. A spatial model suggests that plant communities are a mosaic of positive and negative interactions, which may contribute to population homeostasis and plant diversity

Quantification of mycorrhizal limitation in beech spread

Establishment of Nothofagus spp. into grasslands can be limited by a lack of ectomycorrhizal inoculum, but the degree of mycorrhizal inoculum limitation and how far mycorrhizal inoculum spreads from forest edges has not been quantified. Further, it has been hypothesised, but not confirmed, that established Kunzea ericoides (a native Myrtaceae tree with both ectomycorrhizal and arbuscular mycorrhizal associations) could serve as an alternative host for ectomycorrhizal fungi and thus facilitate mycorrhizal infection of Nothofagus. To confirm and quantify these hypotheses, first we used an ex situ, intact-soil-core bioassay of soils collected near Nothofagus solandri var. cliffortioides forest, near established Kunzea, and in grassland distant from trees of either species. Second, we collected soils along transects of increasing distance from Nothofagus forest into adjacent grasslands. Mycorrhizal infection of Nothofagus solandri var. cliffortioides seedlings was high in soils from Near-Nothofagus and Near-Kunzea (74% and 67% of root tips, respectively) and lower in soils Distant from trees (28% of root tips). Seedlings in soils from Near-Nothofagus also had 3.4× greater biomass than those in soils Distant from trees. In the transects, mycorrhizal infection declined in a stepwise fashion at approximately 16 m distance from the forest edge, and seedling biomass was positively correlated with mycorrhizal infection. These data confirm that a lack of mycorrhizal inoculum can limit seedling establishment and show that Kunzea can provide an alternative host for Nothofagus-compatible mycorrhizal inoculum. Further, they provide quantitative data for spatially explicit models of woody establishment. Forty percent of seedlings in soils collected distant from trees had greater than 20% infection, suggesting that a lack of mycorrhizal inoculum is not a complete barrier to woody establishment, but instead may act as one of multiple environmental filters slowing beech spread. © New Zealand Ecological Society

Environmental profiles of construction materials, components and buildings for the UK

A Life Cycle Assessment (LCA) methodology for construction products has been established with UK construction materials producers. The method provides "level-playing field" LCA for all types of construction materials. Environmental Profiles provide a consideration of materials as part of building elements, including maintenance and replacement. A software tool called ENVEST TM uses this data to analyse the whole building. This gives the impact of the structure and operational impacts of a design over a set lifetime, in UK Ecopoints. The use of Ecopoints for life cycle assessment results enables environmental issues to be integrated into life cycle design alongside financial costs

Mycorrhizal co-invasion and novel interactions depend on neighborhood context

© 2015 by the Ecological Society of America. Biological invasions are a rapidly increasing driver of global change, yet fundamental gaps remain in our understanding of the factors determining the success or extent of invasions. For example, although most woody plant species depend on belowground mutualists such as mycorrhizal fungi and nitrogen-fixing bacteria, the relative importance of these mutualisms in conferring invasion success is unresolved. Here, we describe how neighborhood context (identity of nearby tree species) affects the formation of belowground ectomycorrhizal partnerships between fungi and seedlings of a widespread invasive tree species, Pseudotsuga menziesii (Douglas-fir), in New Zealand.We found that the formation of mycorrhizal partnerships, the composition of the fungal species involved in these partnerships, and the origin of the fungi (co-invading or native to New Zealand) all depend on neighborhood context. Our data suggest that nearby ectomycorrhizal host trees act as both a reservoir of fungal inoculum and a carbon source for late-successional and native fungi. By facilitating mycorrhization of P. menziesii seedlings, adult trees may alleviate mycorrhizal limitation at the P. menziesii invasion front. These results highlight the importance of studying biological invasions across multiple ecological settings to understand establishment success and invasion speed

What can possibly go wrong? The risks of introducing soil microorganisms from Antarctica into South America = ¿Qué puede salir mal? : Los riesgos de introducir microorganismos del suelo de la Antártida en América del Sur

Endophytic fungi form mutualistic associations with plant roots which can increase plant survival and resistance to stress. Recently, it has been proposed that endophytic fungi from Antarctica should be used to facilitate reintroduction and establishment of native plants in xeric environments of northern Chile. In this note, we suggest this is a risky proposition and may lead to biological invasions. It is difficult to predict which endophytic fungi will become invasive, where they will invade, or what their impacts will be. Organisms that move across continents may or may not become invasive depending on the interaction between the species and the invaded community; unexpected outcomes may occur due to adaptation and novel interactions of the introduced species in the new environment. The fact that these endophytes are mutualistic does not imply that they will not have negative effects on the recipient community, since they might promote invasion of other non-native species or may change the competitive relationships among native species. Further, taxonomically uncharacterized fungal isolates from plant roots are likely to contain non-beneficial species. The fact that these endophytic fungi species are from Antarctica does not ensure that they cannot invade elsewhere. It should be recognized that invasive microorganisms are extremely difficult to control. We strongly suggest that the further translocation, use and spread of endophytes from Antarctica should be halted until a risk assessment is undertaken. Biosecurity measures must be taken when considering transcontinental experiments. Based on previous experiences, it is likely that the risk and potential costs of introducing these new species significantly exceed any potential benefits of their introductionsLos hongos endófitos forman asociaciones mutualísticas con raíces de plantas y pueden mejorar la sobrevivencia y resistencia al estrés. Recientemente se ha propuesto usar hongos endófitos de la Antártida para facilitar la reintroducción y establecimiento de plantas nativas en formaciones xerofíticas del norte de Chile. En esta nota se sugiere que aquello es una propuesta riesgosa y puede conducir a invasiones biológicas. Es difícil predecir qué especies se convertirán en invasoras, dónde lo harán o cuáles serán sus efectos. Los organismos transportados entre continentes pueden o no convertirse en invasores, según las interacciones entre especies y con la comunidad invadida, y pueden ocurrir resultados inesperados debido a adaptaciones de especies invasoras al nuevo ambiente y a novedosas interacciones con especies introducidas en el nuevo ambiente. Estos endófitos mutualistas pueden tener efectos negativos en la comunidad receptora, como promover invasiones de otras especies exóticas o cambiar relaciones de competencia entre especies nativas. Los hongos endófitos de la Antártida no garantizan que no puedan invadir otros lugares. La falta de identificación taxonómica de tales hongos impide saber si estos inóculos contienen especies no beneficiosas, como patógenos del suelo. Los microorganismos invasores son extremadamente difíciles de controlar. Por ello, se recomienda que la translocación, uso y dispersión de hongos endófitos antárcicos debiera detenerse hasta tener una evaluación del riesgo de su introducción. Medidas de bioseguridad deben tomarse en experimentos transcontinentales. Según experiencias anteriores, el riesgo y costos potenciales de introducir estas especies pueden superar ampliamente cualquier beneficio potencial de su uso.Fil: Nuñez, Martin A. Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad del Comahue. INIBIOMA. Grupo de Ecología de Invasiones; ArgentinaFil: Dimarco, Romina Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Dickie, Ian A. Lincoln University. Bio-Protection Research Centre; Nueva ZelandaFil: Pauchard, Anibal. Universidad de Concepción. Facultad de Ciencias Forestales. Laboratorio de Invasiones Biolóogicas; Chile. Institute of Ecology and Biodiversity (IEB); Chil

Towards management of invasive ectomycorrhizal fungi

Ectomycorrhizal fungi are increasingly recognized as invasive species. Invasive ectomycorrhizal fungi can be toxic to humans, may compete with native, edible or otherwise valuable fungi, facilitate the co-invasion of trees, and cause major changes in soil ecosystems, but also have positive effects, enabling plantation forestry and, in some cases, becoming a valuable food source. Land-managers are interested in controlling and removing invasive fungi, but there are few available strategies for management and none are based on robust scientific evidence. Nonetheless, despite the absence of relevant experiments, we suggest that knowledge of the fundamental ecology of fungi can help guide strategies. We review the literature and suggest potential strategies for prevention, for slowing the spread of invasive fungi, for eradication, and for long-term management. In many cases the most appropriate strategy will be species and context (including country) specific. In order to effectively address the problems posed by invasive ectomycorrhizal fungi, land managers and scientists need to work together to develop and robustly test control and management strategies

Is Oak Establishment in Old‐fields and Savanna Openings Context Dependent?

Multiple factors are known to influence tree seedling establishment, yet the degree to which these factors depend on each other and on spatial context is largely unknown. We examined the influence of herbaceous competition and water and nitrogen limitations on tree seedling establishment as functions of distance from trees (within‐site spatial context) and site history (between‐site spatial context; as old‐fields vs. savanna openings). We grew Quercus ellipsoidalis E.J. Hill (pin oak) and Q. macrocarpa Michx. (bur oak) seedlings for 3 years in abandoned agricultural fields and savannas in central Minnesota, USA, near and distant from adult oak trees, with and without water and nitrogen resource additions, and with and without clipping of herbaceous vegetation (reducing above‐ground competition). The strongest treatment effects were found in response to distance from trees and clipping herbaceous vegetation. Ectomycorrhizal infection, year 1 foliar N concentrations, and survival were greater in seedlings growing near vs. distant from adult trees, while clipping herbaceous vegetation increased above‐ground seedling biomass but reduced seedling heights, regardless of distance from adult trees. There were conflicting effects of resource addition, which were dependent on clipping of herbaceous vegetation and site (savanna vs. old‐field). Distance from adult trees and clipping herbaceous vegetation appear to have largely independent effects. Thus, while being near trees benefits seedlings, probably via increased mycorrhizal infection, competition from herbaceous vegetation limits seedlings regardless of distance from trees. In contrast, the effects of resource addition were more context dependent, interacting significantly with herbaceous context and site. The factors influencing seedling success can perhaps be best conceptualized as a series of largely independent environmental filters: seedlings near trees have increased mycorrhizal infection, nutrient uptake and survival, but face competition from herbaceous vegetation regardless of distance from trees. The slow encroachment of woody vegetation into old‐fields and savanna openings in this region is likely to be the result of the net cumulative effect of such filters

A common framework for identifying linkage rules across different types of interactions

Species interactions, ranging from antagonisms to mutualisms, form the architecture of biodiversity and determine ecosystem functioning. Understanding the rules responsible for who interacts with whom, as well as the functional consequences of these interspecific interactions, is central to predict community dynamics and stability. Species traits sensu lato may affect different ecological processes by determining species interactions through a two-step process. First, ecological and life-history traits govern species distributions and abundance, and hence determine species co-occurrence and the potential for species to interact. Secondly, morphological or physiological traits between co-occurring potential interaction partners should match for the realization of an interaction. Here, we review recent advances on predicting interactions from species co-occurrence and develop a probabilistic model for inferring trait matching. The models proposed here integrate both neutral and trait-matching constraints, while using only information about known interactions, thereby overcoming problems originating from undersampling of rare interactions (i.e. missing links). They can easily accommodate qualitative or quantitative data and can incorporate trait variation within species, such as values that vary along developmental stages or environmental gradients. We use three case studies to show that the proposed models can detect strong trait matching (e.g. predator‿prey system), relaxed trait matching (e.g. herbivore‿plant system) and barrier trait matching (e.g. plant‿pollinator systems). Only by elucidating which species traits are important in each process (i.e. in determining interaction establishment and frequency), we can advance in explaining how species interact and the consequences of these interactions for ecosystem functioning. A lay summary is available for this articlePeer Reviewe