Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> The 1986 Chernobyl accident resulted in radionuclide contamination (dominated by 137Cs) across large areas of Belarus. Consequences of this accident continue to affect Belarus long after initial contamination, which in turn has placed strain upon social, economic and political infrastructures. One method to reduce this strain and remediate contamination is to return areas of land no longer posing a risk, back to an appropriate use. As a method of remediation, this requires regular and accurate monitoring of the landscape at which existing ground based techniques have not been entirely well‐suited. Remote sensing, specifically the use of imaging spectrometry offers the potential to monitor the Belarusian landscape at opportune spatial and temporal resolutions. Vegetation has been shown to be an important agent in the cycling of radioactive isotopes in the environment and therefore a useful indicator of radionuclide contamination. This pilot research has focused on assessing the spectral response from Pinus... <s> BIB001 </s> Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> An opinion piece published in Nature proposed a global network for agricultural monitoring [J. Sachs, R. Remans, S. Smukler, L. Winowiecki, S. J. Andelman, K. G. Cassman, D. Castle, R. DeFries, G. Denning, J. Fanzo, L. E. Jackson, R. Leemans, J. Leemans, J. C. Milder, S. Naeem, G. Nziguheba, C. A. Palm, J. P. Reganold, D. D. Richter, S. J. Scherr, J. Sircely, C. Sullivan, T. P. Tomich and P. A. Sanchez, Nature, 2010, 466, 558-560.]. Whilst we agree with Sachs et al. that monitoring of agricultural systems is a critically important activity of global significance, especially given increasing problems with global food security and the potential impacts of agriculture on the environment [J. Cribb, The Coming Famine. The Global Food Crisis and What We Can Do to Avoid It, CSIRO Publishing and University of California Press, Melbourne and Oakland, 2010.], we argue in this paper that their generic, mandated monitoring framework has a high probability of failure or at best will be highly inefficient. We base this conclusion on our recently published examination of the factors influencing the success or failure of monitoring programs worldwide [D. B. Lindenmayer and G. E. Likens, Effective Ecological Monitoring, CSIRO Publishing and Earthscan, Melbourne and London, 2010.]. We briefly outline what we believe are three serious flaws in the monitoring framework proposed by Sachs et al. We then suggest an alternative approach that we argue would be more effective, more efficient, and have a greater chance of successfully addressing key issues in sustainable agriculture. <s> BIB002 </s> Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> Abstract The bark beetle (Ips typographus L.) is known for the detrimental impact it can have on Europe’s mature spruce forests with bark beetle outbreaks already having devastated thousands of hectares of spruce forests in Germany. This study analysed the hypothesis that the vitality of spruce vegetation is already susceptible from factors such as climate change or emissions to a certain extent before infestation, so that the role of the subsequent bark beetle infestation is only secondary. Hyperspectral remote-sensing techniques were used to detect changes in biochemical–biophysical vegetation characteristics in the spruce forest of the Bavarian Forest National Park, Germany. For this study, several spectral bands, vegetation indices and specific spectral band combinations of hyperspectral HyMAP remote-sensing data with a 4 m and a 7 m ground resolution were analysed and compared in terms of their classification accuracy, generating an ID3 decision tree. The vitality classes and thus also the attack stages of the spruce vegetation could be estimated with moderate to good accuracy using hyperspectral remote-sensing data. Clear spectral differences between the class with spruce trees that were still green but with reduced vitality (possibly the first stages of green-attack) and the class with healthy spruce trees could be ascertained. The best spectral characteristics, spectral indicators and spectral derivatives related to vitality classes and thus attack stages were typically based on wavebands related to prominent chlorophyll absorption features in the VI within the spectral range of 450–890 nm. Only limited spectral information and derivatives could be found in the short-wave infrared region 1 (SWIR) within the spectral range of 1400–1800 nm, which reflects the water content of the spruce needles. The class of spruce trees that were still green but with reduced vitality (possibly the first stages of green-attack) showed a trend towards detectability and differentiation with spectral indicators and index derivatives. However, the prediction of observed effects with 64% accuracy as observed here is regarded as insufficient in forestry practises. Hyperspectral data with a ground resolution of 4 m were found to contain more information relevant to estimating the vitality class of spruce vegetation compared to hyperspectral data with a ground resolution of 7 m. <s> BIB003 </s> Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> Summary 1. Biodiversity–ecosystem functioning (BEF) experiments address ecosystem-level consequences of species loss by comparing communities of high species richness with communities from which species have been gradually eliminated. BEF experiments originally started with microcosms in the laboratory and with grassland ecosystems. A new frontier in experimental BEF research is manipulating tree diversity in forest ecosystems, compelling researchers to think big and comprehensively. 2. We present and discuss some of the major issues to be considered in the design of BEF experiments with trees and illustrate these with a new forest biodiversity experiment established in subtropical China (Xingangshan, Jiangxi Province) in 2009/2010. Using a pool of 40 tree species, extinction scenarios were simulated with tree richness levels of 1, 2, 4, 8 and 16 species on a total of 566 plots of 25� 8 9 25� 8m each. 3. The goal of this experiment is to estimate effects of tree and shrub species richness on carbon storage and soil erosion; therefore, the experiment was established on sloped terrain. The following important design choices were made: (i) establishing many small rather than fewer larger plots, (ii) using high planting density and random mixing of species rather than lower planting density and patchwise mixing of species, (iii) establishing a map of the initial ‘ecoscape’ to characterize site heterogeneity before the onset of biodiversity effects and (iv) manipulating tree species richness not only in random but also in trait-oriented extinction scenarios. 4. Data management and analysis are particularly challenging in BEF experiments with their hierarchical designs nesting individuals within-species populations within plots within-species compositions. Statistical analysis best proceeds by partitioning these random terms into fixed-term contrasts, for example, species composition into contrasts for species richness and the presence of particular functional groups, which can then be tested against the remaining random variation among compositions. 5. We conclude that forest BEF experiments provide exciting and timely research options. They especially require careful thinking to allow multiple disciplines to measure and analyse data jointly and effectively. Achiev <s> BIB004 </s> Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> Assessing the ecological impacts of environmental change requires knowledge of the relationship between biodiversity and ecosystem functioning. The exact nature of this relationship can differ considerably between ecosystems, with consequences for the efficacy of species diversity as a buffer against environmental change. Using a microbial model system, we show that the relationship can vary depending on environmental conditions. Shapes suggesting functional redundancy in one environment can change, suggesting functional differences in another environment. We find that this change is due to shifting species roles and interactions. Species that are functionally redundant in one environment may become pivotal in another. Thus, caution is advised in drawing conclusions about functional redundancy based on a single environmental situation. It also implies that species richness is important because it provides a pool of species with potentially relevant traits. These species may turn out to be essential performers or partners in new interspecific interactions after environmental change. Therefore, our results challenge the generality of functional redundancy. <s> BIB005 </s> Understanding Forest Health with Remote Sensing -Part I—A Review of Spectral Traits, Processes and Remote-Sensing Characteristics <s> Stress and Adaptation in FES <s> Numerous organisms have shown an ability to survive and reproduce under low-dose ionizing radiation arising from natural background radiation or from nuclear accidents. In a literature review, we found a total of 17 supposed cases of adaptation, mostly based on common garden experiments with organisms only deriving from typically two or three sampling locations. We only found one experimental study showing evidence of improved resistance to radiation. Finally, we examined studies for the presence of hormesis (i.e., superior fitness at low levels of radiation compared with controls and high levels of radiation), but found no evidence to support its existence. We conclude that rigorous experiments based on extensive sampling from multiple sites are required. <s> BIB006
From an evolutionary perspective, FES constitute the final stage of succession and thus the longest lived and largest plant species on land BIB004 . In fast-growing primary producer systems, interactions could be found between biodiversity and the functions, stability, vitality or health of ecosystems BIB004 whereas these are difficult to measure and understand in long lived FES. In their phylogenetic evolution, forests have developed adaptation strategies and reaction mechanisms to multiple-stress factors. Due to the long life of trees, there is still little knowledge about the length of time and the extent to which trees have to be impaired by stress factors in order to be able to observe visible changes in the branching geometry, necrobiotic processes, leaf production and tree functional processes BIB003 . Forest ecosystems can therefore appear to be stable over very long periods of time, when in reality they are irreversibly impaired. Lindenmayer and Likens BIB002 showed that species are not equally sensitive to environmental stress factors and changes. In addition to the species  , a number of other factors can be crucial, including age BIB001 or the occupation of different ecological niches. Research work conducted after the nuclear reactor disaster from Chernobyl has provided important insights into the stress behaviour of different species. It was proven that intensive levels of exposure to radioactivity led to changes in trees, but the intensity and direction of the reaction depended on the tree species BIB006 . Furthermore, the ability of different tree species to adapt to expected climate change is still very much unclear  . At the same time, the effects of multiple stress factors on FH must be understood. It could be proven that a change in complex stress factors can have an influence in changing the respective system functions. Thus, when faced with changes from multiple stress factors, species and populations are able to adapt their respective functions or to take on complementary functions in the ecosystem BIB005 . To really understand FH in all of its complexity, the implementation of RS technologies as a global strategy for monitoring FH is imperative, which firstly entails understanding the basic principles, limitations and constraints of RS for monitoring FH.