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Copyright of New Phytologist is the property of Wiley-Blackwell 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.)

Copyright of Biotropica is the property of Wiley-Blackwell 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.)

Copyright of Ecology is the property of Wiley-Blackwell 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.)

Summary: The fate of tropical forests under climate change is unclear as a result, in part, of the uncertainty in projected changes in precipitation and in the ability of vegetation models to capture the effects of drought‐induced mortality on aboveground biomass (AGB). We evaluated the ability of a terrestrial biosphere model with demography and hydrodynamics (Ecosystem Demography, ED2‐hydro) to simulate AGB and mortality of four tropical tree plant functional types (PFTs) that operate along light‐ and water‐use axes. Model predictions were compared with observations of canopy trees at Barro Colorado Island (BCI), Panama. We then assessed the implications of eight hypothetical precipitation scenarios, including increased annual precipitation, reduced inter‐annual variation, El Niño‐related droughts and drier wet or dry seasons, on AGB and functional diversity of the model forest. When forced with observed meteorology, ED2‐hydro predictions capture multiple BCI benchmarks. ED2‐hydro predicts that AGB will be sustained under lower rainfall via shifts in the functional composition of the forest, except under the drier dry‐season scenario. These results support the hypothesis that inter‐annual variation in mean and seasonal precipitation promotes the coexistence of functionally diverse PFTs because of the relative differences in mortality rates. If the hydroclimate becomes chronically drier or wetter, functional evenness related to drought tolerance may decline. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell 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.)

Aim We assessed the rates of turnover of tree species with distance (beta diversity) in wet forests of the Western Ghats (WG) complex of India to see whether climate, topographic variation or species traits influence beta diversity. Location The Western Ghats is a chain of mountains about 1600 km in length, running parallel to the western coast of the Indian Peninsula from above 8° N to almost 21° N latitude. Methods We used data from 60 small plot inventories concentrated in three regions: the southernmost part of the Western Ghats (SWG) (8°24′ to 9°37′ N), the Nilgiri Hills (11°12′ to 11°14′ N), and the central Western Ghats (CWG) (12°32′ to 14°51′ N). We used Sorensen's index (SI) to estimate the similarity in species composition between two plots and regressed SI against the logarithm of the distance between plots to assess beta diversity. A bootstrapping procedure provided confidence intervals for regression coefficients. To test for the effects of climate, we regressed seasonality differences between plots against SI for low-elevation (< 800 m) plots along the north–south axis, and all plots in the SWG. We assessed the impact of the rainfall gradient in the Kogar region. Results Among all three regions, beta diversity was highest along the latitudinal axis, and along the rainfall gradient in the Kogar region. Differences in seasonality between sites were strongly related to beta diversity along the north–south seasonality gradient and within the SWG. Within the three regions, beta diversity was highest in the region with the strongest rainfall gradient and lowest for the topographically heterogeneous SWG. Beta diversity did not differ between forest strata and dispersal modes. Main conclusions We conclude that climate, particularly seasonality, is probably the primary driver of beta diversity among rain forest trees of the Western Ghats complex. [ABSTRACT FROM AUTHOR]

Abstract: Soil microbial properties are known to exhibit high spatial and temporal variability, which can hinder our understanding of the effects of agricultural management on soil microbial activities, populations and communities. However, if this variability is explicitly considered in soil sampling schemes, experimental results can help us better understand soil microbial properties. In this initial assessment of soil resources and microbial properties in a 16-ha landscape planted to corn, we hypothesized that soil microbial properties will vary by soil type. We defined soil type based on drainage class (4 levels), series (7 levels), map unit (11 levels), and texture of the Ap horizon (3 levels). We took soil samples from 16 map units in April, June, August, and October and measured 12 physical and chemical properties, and 27 microbial properties on at least one of these dates. Soil physical and chemical properties generally varied with soil type and canonical discriminant analyses showed that soil drainage classes, series, and map units were delineated by a similar set of soil properties (total C, total N, moisture, pH, equivalent CEC (CECe), and available P). Ap texture classes were delineated by a different set of soil properties (available K, Mg, and Ca and CECe). A number of soil microbial properties varied by soil type, but, in general, a smaller proportion of measured soil microbial properties showed soil type effects compared to the proportion of soil physical and chemical properties that showed soil type effects. Method of soil classification strongly influenced which soil microbial properties varied by soil type. However, soil microbial activities, population sizes, and community structures were generally greater or most unique in mid-range soils regardless of how soils were classified, possibly because soil moisture was optimal for microbiological activity and growth in these soils. Except at the level of drainage class, there was little consistency between patterns of variation in soil physical and chemical properties and patterns of variation in soil microbial properties among soil types. Thus, different soil sampling strategies may be required when accounting for variation in soil physical and chemical properties than when accounting for soil microbial properties at the landscape level. While sampling soils according to soil survey-defined map units indicated that some soil microbial properties vary by soil type, a number of limitations to this approach are discussed. To improve upon results presented here, future efforts to quantify landscape level variation of soil microbial properties should probably be sampled at a finer scale that explicitly accounts for soil properties that vary at the sub-map unit level, including terrain attributes, microtopography, soil texture, soil bulk density, and other factors that impact soil temperature and moisture dynamics. [Copyright &y& Elsevier]