Soil resources and topography shape local tree community structure in tropical forests

Both habitat filtering and dispersal limitation influence the compositional structure of forest communities, but previous studies examining the relative contributions of these processes with variation partitioning have primarily used topography to represent the influence of the environment. Here, we bring together data on both topography and soil resource variation within eight large (24-50 ha) tropical forest plots, and use variation partitioning to decompose community compositional variation into fractions explained by spatial, soil resource and topographic variables. Both soil resources and topography account for significant and approximately equal variation in tree community composition (9-34% and 5-29%, respectively), and all environmental variables together explain 13-39% of compositional variation within a plot. A large fraction of variation (19-37%) was spatially structured, yet unexplained by the environment, suggesting an important role for dispersal processes and unmeasured environmental variables. For the majority of sites, adding soil resource variables to topography nearly doubled the inferred role of habitat filtering, accounting for variation in compositional structure that would previously have been attributable to dispersal. Our results, illustrated using a new graphical depiction of community structure within these plots, demonstrate the importance of small-scale environmental variation in shaping local community structure in diverse tropical forests around the globe. © 2012 The Author(s) Published by the Royal Society. All rights reserved

<em>Austroeupatorium inulifolium</em>nvasion alters soil microbial populations to facilitate its own growth

It is a known fact that invasive plants perform better in their introduced range than in the native range.  The invasion-driven modifications of the soil microbial community and alleolopathic compounds are considered as factors contributing to their success over co-occurring natives.  Here we present evidence to show that Austroeupatorium inulifolium invasion has altered the soil microbial population to facilitate its own growth.  A pot experiment showed higher growth increments in Austroeupatorium when grown in soil with a history of Austroeupatorium invasion compared to that with no history of invasion.  The native, Psiadia ceylanica showed no parallel growth increments when grown under similar conditions.  In support, the enzyme activities (catalase and dehydrogenase) and soil microbial biomass carbon also recorded higher values in invaded soils compared to un-invaded soils. Further, Austroeupatorium showed higher dependence on arbuscular mycorrhizal fungi (AMF) than that of the native, Psiadia.  The results suggest that Austroeupatorium invasion has enhanced soil microbial populations and functions in order to take the advantage over other natives

Two new localities of the endangered fish Systomus martenstyni (Kottelat &amp;amp; Pethiyagoda, 1991) (Teleostei: Cyprinidae) found in Sri Lanka

Systomus martenstyni is an endemic and endangered fish of Sri Lanka. This species was earlier known to be restricted to the Amban Ganga River basin. Recently two populations of S. martenstyni were located in two major tributaries of River Mahaweli: Loggal Oya and Badulu Oya in the Uva province of Sri Lanka. These new populations are relatively small and are facing the threat of habitat quality degradation and habitat loss. Effective conservation actions should be undertaken to conserve this endangered fish species

Soil resources and topography shape local tree community structure in tropical forests

Both habitat filtering and dispersal limitation influence the compositional structure of forest communities, but previous studies examining the relative contributions of these processes with variation partitioning have primarily used topography to represent the influence of the environment. Here, we bring together data on both topography and soil resource variation within eight large (24–50 ha) tropical forest plots, and use variation partitioning to decompose community compositional variation into fractions explained by spatial, soil resource and topographic variables. Both soil resources and topography account for significant and approximately equal variation in tree community composition (9–34% and 5–29%, respectively), and all environmental variables together explain 13–39% of compositional variation within a plot. A large fraction of variation (19–37%) was spatially structured, yet unexplained by the environment, suggesting an important role for dispersal processes and unmeasured environmental variables. For the majority of sites, adding soil resource variables to topography nearly doubled the inferred role of habitat filtering, accounting for variation in compositional structure that would previously have been attributable to dispersal. Our results, illustrated using a new graphical depiction of community structure within these plots, demonstrate the importance of small-scale environmental variation in shaping local community structure in diverse tropical forests around the globe

Checklist, typification details, and nomenclature status of ascomycetous fungi originally described in Sri Lanka.

Despite being a biodiversity-rich country, Sri Lanka’s fungal diversity remains largely unexplored. In the 19th century, British mycologists conducted extensive research, leading to the identification of more than 1,800 fungal taxa, including ascomycetous and basidiomycetous species. However, the majority of these taxa have not been revisited since their initial description, and molecular evidence is lacking. Moreover, a significant number of fungal taxa have been deemed invalid or illegitimate, indicating the need for a nomenclatural revision. To address this knowledge gap, this review provides a comprehensive list of ascomycetous taxa (including both lichen-forming and non-lichenized) that were originally described in Sri Lanka. Names are listed according to the original names which were included in the protologue. In the cases where species have been transferred to other genera, the current names and new classifications are provided. The typification details, nomenclature status, and classification are also presented. This checklist will serve as a valuable resource for the future epitypification of old taxa, as much of the existing information is poorly documented and scattered

Reviewing the world's edible mushroom species: A new evidence‐based classification system

Wild mushrooms are a vital source of income and nutrition for many poor communities and of value to recreational foragers. Literature relating to the edibility of mushroom species continues to expand, driven by an increasing demand for wild mushrooms, a wider interest in foraging, and the study of traditional foods. Although numerous case reports have been published on edible mushrooms, doubt and confusion persist regarding which species are safe and suitable to consume. Case reports often differ, and the evidence supporting the stated properties of mushrooms can be incomplete or ambiguous. The need for greater clarity on edible species is further underlined by increases in mushroom-related poisonings. We propose a system for categorizing mushroom species and assigning a final edibility status. Using this system, we reviewed 2,786 mushroom species from 99 countries, accessing 9,783 case reports, from over 1,100 sources. We identified 2,189 edible species, of which 2,006 can be consumed safely, and a further 183 species which required some form of pretreatment prior to safe consumption or were associated with allergic reactions by some. We identified 471 species of uncertain edibility because of missing or incomplete evidence of consumption, and 76 unconfirmed species because of unresolved, differing opinions on edibility and toxicity. This is the most comprehensive list of edible mushrooms available to date, demonstrating the huge number of mushrooms species consumed. Our review highlights the need for further information on uncertain and clash species, and the need to present evidence in a clear, unambiguous, and consistent manner