211 research outputs found

    Age-related changes in anatomical and morphological leaf traits of Wollemia nobilis

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    The results highlight significant variations of Wollemia nobilis leaf traits which reflect age-related changes of the subsequent growth units along the branches. Age-related changes appear in a gradual increase of leaf size from young leaves to old leaves. The LMA increasing from 13.75 g/cm(2) in current year leaves to 24.84 g/cm(2) in 7 year leaves is associated with an increment of the number of lignified elements (vascular tissues, astrosclereids), of hypodermal and epidermal-cuticle structures (cuticle, wax layer) and of oil bodies abundance, which may increase resistance to stress factors. These characteristics highlight that W. nobilis leaves can adapt to variable environmental conditions with a return rate on a larger time-scale since leaves on a branch stay alive for a long time until the branch dies

    Collating and validating indigenous and local knowledge to apply multiple knowledge systems to an environmental challenge: A case-study of pollinators in India

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    There is an important role for indigenous and local knowledge in a Multiple Evidence Base to make decisions about the use of biodiversity and its management. This is important both to ensure that the knowledge base is complete (comprising both scientific and local knowledge) and to facilitate participation in the decision making process. We present a novel method to gather evidence in which we used a peer-to-peer validation process among farmers that we suggest is analogous to scientific peer review. We used a case-study approach to trial the process focussing on pollinator decline in India. Pollinator decline is a critical challenge for which there is a growing evidence base, however, this is not the case world–wide. In the state of Orissa, India, there are no validated scientific studies that record historical pollinator abundance, therefore local knowledge can contribute substantially and may indeed be the principle component of the available knowledge base. Our aim was to collate and validate local knowledge in preparation for integration with scientific knowledge from other regions, for the purpose of producing a Multiple Evidence Base to develop conservation strategies for pollinators. Farmers reported that vegetable crop yields were declining in many areas of Orissa and that the abundance of important insect crop pollinators has declined sharply across the study area in the last 10–25 years, particularly Apis cerana, Amegilla sp. and Xylocopa sp. Key pollinators for commonly grown crops were identified; both Apris cerana and Xylocopa sp. were ranked highly as pollinators by farmer participants. Crop yield declines were attributed to soil quality, water management, pests, climate change, overuse of chemical inputs and lack of agronomic expertise. Pollinator declines were attributed to the quantity and number of pesticides used. Farmers suggested that fewer pesticides, more natural habitat and the introduction of hives would support pollinator populations. This process of knowledge creation was supported by participants, which led to this paper being co-authored by both scientists and farmers

    Higher thermal acclimation potential of respiration but not photosynthesis in two alpine Picea taxa in contrast to two lowland congeners

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    The members of the genus Picea form a dominant component in many alpine and boreal forests which are the major sink for atmospheric CO2. However, little is known about the growth response and acclimation of CO2 exchange characteristics to high temperature stress in Picea taxa from different altitudes. Gas exchange parameters and growth characteristics were recorded from four year old seedlings of two alpine (Picea likiangensis vars. rubescens and linzhiensis) and two lowland (P. koraiensis and P. meyeri) taxa. Seedlings were grown at moderate (25°C/15°C) and high (35°C/25°C) day/night temperatures, for four months. The approximated biomass increment (ΔD2H) for all taxa decreased under high temperature stress, associated with decreased photosynthesis and increased respiration. However, the two alpine taxa exhibited lower photosynthetic acclimation and higher respiratory acclimation than either lowland taxon. Moreover, higher leaf dry mass per unit area (LMA) and leaf nitrogen content per unit area (Narea), and a smaller change in the nitrogen use efficiency of photosynthesis (PNUE) for lowland taxa indicated that these maintained higher homeostasis of photosynthesis than alpine taxa. The higher respiration rates produced more energy for repair and maintenance biomass, especially for higher photosynthetic activity for lowland taxa, which causes lower respiratory acclimation. Thus, the changes of ΔD2H for alpine spruces were larger than that for lowland spruces. These results indicate that long term heat stress negatively impact on the growth of Picea seedlings, and alpine taxa are more affected than low altitude ones by high temperature stress. Hence the altitude ranges of Picea taxa should be taken into account when predicting changes to carbon fluxes in warmer conditions
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