Synthetic mosquito oviposition attractants are sorely needed for surveillance and control programs for Culex species, which are major vectors of pathogens causing various human diseases, including filariasis, encephalitis, and West Nile encephalomyelitis. We employed novel and conventional chemical ecology approaches to identify potential attractants, which were demonstrated in field tests to be effective for monitoring populations of Cx. p. quinquefasciatus in human dwellings. Immunohistochemistry studies showed that an odorant-binding protein from this species, CquiOBP1, is expressed in trichoid sensilla on the antennae, including short, sharp-tipped trichoid sensilla type, which house an olfactory receptor neuron sensitive to a previously identified mosquito oviposition pheromone (MOP), 6-acetoxy-5-hexadecanolide. CquiOBP1 exists in monomeric and dimeric forms. Monomeric CquiOBP1 bound MOP in a pH-dependent manner, with a change in secondary structure apparently related to the loss of binding at low pH. The pheromone antipode showed higher affinity than the natural stereoisomer. By using both CquiOBP1 as a molecular target in binding assays and gas chromatography-electroantennographic detection (GC-EAD), we identified nonanal, trimethylamine (TMA), and skatole as test compounds. Extensive field evaluations in Recife, Brazil, a region with high populations of Cx. p. quinquefasciatus, showed that a combination of TMA (0.9 µg/l) and nonanal (0.15 ng/µl) is equivalent in attraction to the currently used infusion-based lure, and superior in that the offensive smell of infusions was eliminated in the newly developed synthetic mixture.

Please cite this article as: Latte, N., Lebourgeois, F., Claessens, H.,Increased tree-growth synchronization of beech (Fagus sylvatica L.) in response to climate change in northwestern Europe, Dendrochronologia (2015), http://dx.doi.org/10.1016/j.dendro. 2015.01.002 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. responded to climate change, we selected 12 sites (137 trees) with optimal growing conditions 20 along a W−E altitudinal gradient (67-590 m) in Belgium. We evaluated temporal changes in 21 growth response to climate by using pointer year analysis, moving mean sensitivities (1860-22 2011), and moving bootstrapped correlation coefficients . The strongest driving 23 climatic variables were identified by using the partial least squares method. 24The common patterns of growth trends, pointer years, and mean sensitivities among sites 25 provided evidences for the impact of environmental changes operating at a regional scale. The 26 results of growth-climate analysis indicated that these changes were strongly influenced by 27 the climatic conditions of the previous year. The climate sensitivity of beech increased 28 progressively in response to more frequent and intense heat waves and warming-related 29 droughts, especially during recent decades, leading to remarkable inter-site synchronization. 30The changes were much more pronounced for sites located in lowlands (<300 m). The 31 differences in growth responses along the altitudinal gradient and the consequences of 32 warming for beech growth and physiology are discussed. 33

The growth of past, present, and future forests was, is and will be affected by climate variability. This multifaceted relationship has been assessed in several regional studies, but spatially resolved, large-scale analyses are largely missing so far. Here we estimate recent changes in growth of 5800 beech trees (Fagus sylvatica L.) from 324 sites, representing the full geographic and climatic range of species. Future growth trends were predicted considering state-of-the-art climate scenarios. The validated models indicate growth declines across large region of the distribution in recent decades, and project severe future growth declines ranging from −20% to more than −50% by 2090, depending on the region and climate change scenario (i.e. CMIP6 SSP1-2.6 and SSP5-8.5). Forecasted forest productivity losses are most striking towards the southern distribution limit of Fagus sylvatica, in regions where persisting atmospheric high-pressure systems are expected to increase drought severity. The projected 21st century growth changes across Europe indicate serious ecological and economic consequences that require immediate forest adaptation.

Abstract:Deadwood plays an important role in forest ecological processes and is fundamental for the maintenance of biological diversity. Further, it is a forest carbon pool whose assessment must be reported for international agreements dealing with protection and forest management sustainability. Despite wide agreement on deadwood monitoring by national forest inventories (NFIs), much work is still necessary to clarify definitions so that estimates can be directly compared or aggregated for international reporting. There is an urgent need for an international consensus on definitions and agreement on harmonization methods. The study addresses two main objectives: to analyze the feasibility of harmonization procedures for deadwood estimates and to evaluate the impact of the harmonization process based on different definitions on final deadwood estimates. Results are reported for an experimental harmonization test using NFI deadwood data from 9,208 sample plots measured in nine European countries and the United States. Harmonization methods were investigated for volume by spatial position (lying or standing), decay classes, and woody species accompanied by accuracy assessments. Estimates of mean plot volume based on harmonized definitions with minimum length/height of 1 m and minimum diameter thresholds of 10, 12, and 20 cm were on average 3, 8, and 30% smaller, respectively, than estimates based on national definitions. Volume differences were less when estimated for various deadwood categories. An accuracy assessment demonstrated that, on average, the harmonization procedures did not substantially alter deadwood observations (root mean square error 23.17%). FOR. SCI. 58(3):269 -283.

Norway spruce (Picea abies (L.) Karst.) is a major production tree species for the European wood industry. However, it is highly sensitive to bark stripping (BS) by red deer (Cervus elaphus L.), which causes large timber losses. Because the red deer population has increased over the last decades, a better understanding of the underlying causes driving BS is urgently needed. BS outbreaks are multifactorial: winter food shortage, local and regional deer abundance and stand properties (thermal and visual cover, and scarcity of herbaceous layers) have been found to drive BS rates. Although the influence of each of these factors is well studied, there is still no consensus on their relative contributions to BS or what mitigation strategy is best. In this study, we made use of a long-term, large-scale BS inventory (13 years over 2570 km 2) to fill these gaps. We modeled winter and summer BS rates in response to the most explanatory variables, selected from a large set of environmental variables. Our results highlight the prevalence of deer abundance combined with high sensitivity of coniferous thickets and pronounced habitat selection by deer for these stands. Our findings show that the control of red deer populations is a key measure for reducing BS in Norway spruce stands.

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17To characterize growth partitioning within the tree and its responses to climate, we studied 8 dominant beech 18 trees (Fagus sylvatica L.) of a pure, even-aged 98-year-old stand in Belgium. We sampled 10 disks along the 19 stem from breast height to treetop and examined the inter-annual patterns of, and discrepancies between, ring-20 area and volume increments by performing detailed stem analysis and dendroecological investigations. Although 21 the common inter-annual variation among all increment series was high, we observed increasing growth 22 variability and climate sensitivity with height, leading to notable bole-crown discrepancies. Both the common 23 inter-annual variation and bole-crown discrepancies were mainly driven by summer heat waves and related 24 droughts of the previous year, and spring droughts of the current year. Despite these discrepancies, the radial 25 growth at breast height can be considered a good estimate of the tree volume increment but not for the purpose 26 of focusing on climatic effects of isolated years. Extreme climatic conditions increase the risk of inaccurate 27 estimations. The results of the present study are discussed in relation to tree ecophysiology hypotheses. 28

Global change-particularly climate change, forest management, and atmospheric deposition-has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L.) were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87-186 years old). The effects of the developmental stage (i.e., increasing tree size) were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate), mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability («mean sensitivity), mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950-1960s, and growth variability has increased by about 45% since the 1970-1980s. Our results indicate that (1) before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition); and (2) since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands.