The net photosynthetic response matrix to four light levels combined with four temperatures and for a full range of thallus hydration has been defined for a Cladonia–woodland population of Cladonia rangiferina in midsummer and early winter. Maximum rates of net photosynthesis are generated between 150 and 200% thallus water content by weight between 15 and 25 °C with low rates being generated at 5 and 35 °C. Light saturation occurs above 600 μE∙m−2∙s−1. There is no evidence of acclimation of photosynthetic optima to temperature but with the onset of early winter there is a marked decrease of respiration rate. An examination of the sensitivity of Cladonia rangiferina in an air-dry state to heat stress shows a rapid decline of net photosynthesis under 45 °C daytime stress. Although 35 °C initially reduces the level of net photosynthesis to some extent, over a 3-week experimental period no further decline is observed. It is suggested that this population of Cladonia rangiferina, which is markedly restriced to a position under the shade of Ledum shrubs, is protected there from the otherwise excessive heat load which occurs on the open Cladonia stellaris surface and which typically reaches 40 °C under full radiation conditions in summer.
Evidence-based policies are recommended for the enhanced chances of efficacy in achieving policy goals. Achieving this in the policy development process may however require approaches that are not as simple especially in less developed countries, where the research-policy linkage is not commonly the case. This chapter provides a guide to a practical approach that could assist policy makers in similar societies based on the steps adopted in the development of the National Adaptation Strategy and Plan of Action on Climate Change (NASPA-CCN) for Nigeria. The NASPA–CCN has been acknowledged as among the models of climate change policy development that other countries could aim for. It is therefore positioned to offer lessons on policy development in a less developed country environment. The focus in this chapter however is not so much on the subject of climate change but the practical experiences and lessons learnt from the process involved in developing the NASPA-CCN providing lessons learned to mainstream climate change research evidence into policy.
SUMMARYThe seasonal changes in the ability of Cladonia rangiferina to tolerate heat stress are examined in late winter, early spring and in summer. The effects of heat stress are examined as changes in net photosynthetic and respiration rates following air-dry storage of lichen replicates at two stress temperatures, 35 and 45 °C, for 21 days. In late winter the experimental replicates show reduced net photosynthetic rates after 7 days stress treatment at 35 °C. By mid-summer this treatment has no deleterious effects and it is concluded that there is approximately a 10 °C increase in heat tolerance in Cladonia rangiferina between late winter and mid-summer.
This article reports on the evaluation of existing ecological monitoring variables from a variety of sources to select a suite of core variables suitable for monitoring at the Ecological Monitoring and Assessment Network (EMAN) sites located across Canada. The purpose of EMAN is to promote the acquisition of relevant and consistent data that can be used to report on national trends and provide an early warning of ecosystem change. Existing monitoring variables were evaluated in two steps. In the first step, three primary criteria were used to pre-screen preliminary variables. In the second step, a more detailed evaluation considered twenty criteria based on data quality, applicability, data collection methods, data analysis and interpretation, existing data and programs, and cost effectiveness to select a draft set of core monitoring variables (CMV). An ecological framework was developed to organize the CMV in a manner that permitted a gap analysis to confirm the CMV assessed a wide range of relevant environment components. The suite of CMV were then tested to determine their effectiveness in detecting ecosystem change caused by stressors with ecosystem responses that have been well documented in the literature. This project is part of a process lead by Environment Canada to select CMV to detect and track ecosystem change at EMAN sites. It is anticipated that the proposed CMV will undergo future discussion and development leading to the final selection of a suite of CMV for use at EMAN sites.
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