Energy, Resources and the Environment

Words on Wednesday aims at promoting interesting/fun/exciting publications on topics related to Energy, Resources and the Environment. If you would like to be featured on WoW, please send us a link of the paper, or your own post, at ERE.Matters@gmail.com.

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Schickhoff, U., Bobrowski, M., Böhner, J., Bürzle, B., Chaudhary, R. P., Gerlitz, L., Heyken, H., Lange, J., Müller, M., Scholten, T., Schwab, N., and Wedegärtner, R., 2015. Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators, Earth Syst. Dynam., 6, 245-265.

Abstract:

Climate warming is expected to induce treelines to advance to higher elevations. Empirical studies in diverse mountain ranges, however, give evidence of both advancing alpine treelines and rather insignificant responses. The inconsistency of findings suggests distinct differences in the sensitivity of global treelines to recent climate change. It is still unclear where Himalayan treeline ecotones are located along the response gradient from rapid dynamics to apparently complete inertia. This paper reviews the current state of knowledge regarding sensitivity and response of Himalayan treelines to climate warming, based on extensive field observations, published results in the widely scattered literature, and novel data from ongoing research of the present authors.

Anthropogenic treeline in Manang, Nepal, showing an abrupt transition to alpine grazing lands (Schickhoff, 24 September 2013).

Several sensitivity indicators such as treeline type, treeline form, seed-based regeneration, and growth patterns are evaluated. Since most Himalayan treelines are anthropogenically depressed, observed advances are largely the result of land use change. Near-natural treelines are usually krummholz treelines, which are relatively unresponsive to climate change. Nevertheless, intense recruitment of treeline trees suggests a great potential for future treeline advance. Competitive abilities of seedlings within krummholz thickets and dwarf scrub heaths will be a major source of variation in treeline dynamics. Tree growth–climate relationships show mature treeline trees to be responsive to temperature change, in particular in winter and pre-monsoon seasons. High pre-monsoon temperature trends will most likely drive tree growth performance in the western and central Himalaya. Ecological niche modelling suggests that bioclimatic conditions for a range expansion of treeline trees will be created during coming decades.

Climatic treeline (3900–4000 m) on a north-facing slope in Rolwaling, Nepal (Schwab, 18 September 2014).

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Lago-Vila, M., Arenas-Lago, D., Rodríguez-Seijo, A., Andrade Couce, M. L., and Vega, F. A., 2015. Cobalt, chromium and nickel contents in soils and plants from a serpentinite quarry, Solid Earth, 6, 323-335.

Abstract:

The former serpentinite quarry of Penas Albas (Moeche, Galicia, NW Spain) left behind a large amount of waste material scattered over the surrounding area, as well as tailing areas. In this area several soils were studied together with the vegetation growing spontaneously over them with the aim of identifying the bioavailability of heavy metals. The potential of spontaneous vegetation for phytoremediation and/or phytostabilization was evaluated. The pH of the soils ranges from neutral to basic, with very low organic matter and nitrogen contents. There are imbalances between exchangeable cations like potassium (K) and calcium (Ca), mainly due to high magnesium (Mg) content that can strongly limit plant production. Moreover, in all of the studied soils there are high levels of cobalt (Co), chromium (Cr) and nickel (Ni) (>70, >1300 and >1300 mg kg^-1, respectively). They exceed the intervention limits indicated by soil guideline values. Different soil extractions were performed in order to evaluate bioavailability. CaCl₂⋅0.01M is the most effective extraction reagent, although the reagent that best predicts plant availability is a mixture of low molecular weight organic acids. Festuca rubra, L. is the spontaneous plant growing in the soils that accumulates the highest amount of the metals, both in shoot and roots. Festuca also has the highest translocation factor values, although they are only >1 for Cr. The bioconcentration factor is >1 in all of the cases, except in the shoot of Juncus sp. for Co and Ni. The results indicate that Festuca is a phytostabilizer of Co and Ni and an accumulator of Cr, while Juncus sp. is suitable for phytostabilization.

Extraction efficiency. In each soil, bars with different letters
indicate significantly different EF values (p <0.05) for each
metal. Hanging bars are the standard deviation.

plants

Words on Wednesday: Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators

Words on Wednesday: Cobalt, chromium and nickel contents in soils and plants from a serpentinite quarry