Projected climate change scenarios such as frequently occurring dry summer spells are an enormous threat to the health of boreal conifer forests. We identified visible features indicating wood with ...tracheids predisposed for hydraulic and mechanical dysfunction in Norway spruce, suggest why this is formed during severe summer drought and hypothesised on mechanism that would cause tracheid collapse and stem cracks.
Trees from southern Sweden that showed signs of severe reaction to drought, i.e. stem cracks along the trunk, were compared to healthy, undamaged trees. Rings investigated included those formed in 2006, a year with an extremely dry summer season in the study region. In southern Norway, we investigated trees with and without drought-induced top dieback symptoms. We analysed anatomical features such as tracheid lumen diameter, thickness of cell wall and its various layers (S1, S2 and S3), applied Raman imaging in order to get information on the lignin distribution in the cell wall and the compound middle lamellae and performed hydraulic flow and shrinkage experiments.
Although tracheids in annual rings with signs of collapse had higher tangential lumen diameters than those in “normal” annual rings, we conclude that collapse of tracheid walls depends mainly on wall thickness, which is genetically determined to a large extent. Spruce trees that produce earlywood with extremely thin cell walls can develop wall collapse and internal cracks under the impact of dry spells. We also present a new diagnostic tool for detecting individuals that are prone to cell wall collapse and stem cracks: Lucid bands, i.e. bands in the fresh sapwood with very thin cell walls and inhomogeneous lignin distribution in the S-layers and the compound middle lamellae that lost their hydraulic function due to periods of severe summer drought. The detection of genotypes with lucid bands could be useful for an early selection against individuals that are prone to stem cracks under the impact of severe summer drought, and also for early downgrading of logs prone to cracking during industrial kiln drying.
Climate-smart forestry (CSF) is considered a promising approach for climate change adaptation and mitigation strategies, as highlighted in several European policy documents. This paper describes a ...prospective approach to introducing an incentive-based scheme to facilitate the implementation of CSF through a case study in Iceland. It is argued that the payments for ecosystem services (PES) scheme allows for effective CSF management and long-term sustainability if introduced in compliance with local, cultural, and social values. In a case study of an Icelandic afforestation programme, we conducted an institutional analysis of the PES scheme and assessed its effect on the sustainable provision of forest ecosystem services for the long term. We provide preliminary findings on the application of CSF in the 30-year-old Icelandic afforestation programme scheme. The perspectives of forest and policy experts, as well as local farmers participating in the scheme, were crucial for assessing the effectiveness of PES scheme performance in Iceland.
Males usually come into conflict due to competition for territories and females. However, interference competition can also occur between males of congeneric species when their ecological ...requirements are overlapping. Using acoustic playback experiments, we investigated male-male interactions within and between Grasshopper (Locustella naevia; GW) and River Warbler (L. fluviatilis; RW). Our objective was to evaluate the song and behavioural response of tested males of both species to conspecific song stimuli in order to compare this with the response to congeneric stimulus, based on which we could assess whether these two commonly co-existing species show interspecific territorialism. A total of nine GW and 11 RW males were tested in May and June 2019 in western Slovakia. The ability to differentiate between the heterospecific (control), congeneric, and conspecific stimuli was similar between the two species. Conspecific playback elicited the strongest non-vocal response and a significant change in vocalization. The GW males shortened the songs, while the RW males shortened the songs and also increased their syllable rate. The congeneric playback elicited a lower intensity of behavioural response than conspecific playback and no change in vocalization in either species. We conclude that interspecific interference competition between GW and RW is rather low, suggesting that the species' ecological requirements are separated, although these two congeneric species commonly share habitat.
•Males of Locustella species differentiate between conspecific and congeneric stimuli.•Males changed vocalization only to the conspecific stimuli.•Interspecific interference competition is low between the two coexisting species.
Cyclocondensation of salicylaldehydes with alkyl acetoacetates and 2-aminobenzothiazoles or 2-amino-5-methylthiazole under classical Biginelli reaction conditions gives rare hetarylamino substituted ...2,2′-spirobischromanecarboxylate derivatives. The mechanism and observed stereoselectivity of the unexpected pseudo-four-component process are discussed.
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Introduction
Knowledge on the mobility of threatened species is a clue to understanding population dynamics and is needed to develop appropriate conservation strategies. Here, we investigate movement ...patterns of the Bei-Bienko’s Plump Bush-cricket (
Isophya beybienkoi
), an example of a flightless and critically endangered species endemic to the Slovak Karst (southern Slovakia, Central Europe). The capture-mark-recapture method was used to estimate the mobility of the species using fluorescent dye as a marking medium. We found that the mean (± SD) daily distance travelled by this species was only 3.2 ± 2.6 m, with significant differences between males (4.1 ± 3.0 m) and females (2.7 ± 2.1 m). Our results indicate that
I. beybienkoi
is a short-distance disperser. Males disappeared faster than females from the study plots (at maximum, two females were recaptured even after 41 days). The observed movement patterns suggest that the most urgent conservation measure for this species is to improve the habitat quality of sites, which suffer from overgrowth, and to maintain the quality of other suitable sites that might increase the size of the existing subpopulations.
Implications for insect conservation
Our results show that
I. beybienkoi
is a short-distance disperser and wanders only within its optimal habitat. Hence, to incorporate movement behaviour into conservation, one of the measures that should mitigate this threat is to preserve or improve the quality of habitats that suffer from overgrowth, in order to increase the size of existing subpopulations. The observed movement patterns suggest that the species is probably incapable of responding to changes in the availability of suitable habitats by dispersing, indicating a limited exchange of individuals between isolated populations. Thus, to enhance structurally diverse mosaic of high-quality habitats, restoration of migration corridors former used as movement corridors for grazing animals may support the dispersal of the threatened bush-cricket.
A Biginelli‐type condensation using Meldrum's acid has been accomplished in refluxing AcOH to give 6‐substituted dihydropyrimidine‐2,4‐(1H,3H)‐diones. In contrast to other aldehydes, the ...three‐component reaction with salicylaldehyde led to an oxygen‐bridged pyridine. A reaction mechanism is proposed.
A mild protocol for the reaction of 1,3-dicarbonyl compounds with a range of alkenols mediated by CAN was described. The oxidative free radical cyclization leading to corresponding dihydrofuran ...derivatives tolerated the presence of hydroxyl group.
Graphical abstract
Ceric ammonium nitrate-mediated oxidative cyclizations of CH-acids with terpenes and terpene like substrates were investigated. Dimedone, acetylacetone, and methyl nitroacetate were condensed with ...pinene, norbornene, nopol, camphene, and carvone and the reaction stereoselectivity was examined. Condensation with endocyclic double bonds in pinene and nopol displayed stereoselectivity, resulting in the formation of pure enantiomers. Condensation with exocyclic double bonds in camphene and carvone produced enantiomer mixtures. The mechanism of the intramolecular annulation in a nopol derivative is discussed with the help of DFT and ab initio calculations.
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Although forests store significant amounts of carbon in tree stems, the extent to which stem growth depends on carbon assimilation and environmental factors is poorly understood. In this study, gross ...primary productivity (GPP) and net ecosystem productivity (NEP) are compared for the first time at daily resolution with stem carbon allocation (SCA) in a spruce forest.
We found substantial differences in the seasonal patterns of all variables as a function of environmental conditions, leading to three important findings. First, carbon uptake was only marginally invested in wood growth during the first half of the growing season. This means that there were other priorities for carbon allocation than stem growth at this time of year. Second, our results show that SRI at the beginning of the stem growth period, which mainly involves cell division and expansion, is a process that requires less carbon than the process of xylem lignification and thickening that follows. And third, NEP was generally less sensitive to drought than SCA. This suggests that the carbon uptake balance is less sensitive to dry periods than growth, particularly because the carbon uptake period is much longer than the growth window. These results may change the way we perceive the effects of climate change on forests, as tree carbon dynamics are primarily explained by the seasonal timing of dry periods rather than the intensity of these events.
•Novel daily-resolved stem carbon allocation data of spruce trees.•Carbon uptake and allocation are partially decoupled.•Drought limits stem growth of spruce before carbon uptake is affected.•Timing of extreme events determines the impact on the carbon balance of forests.•Spruce trees increasingly suffer under drought stress.
Key message
Presented Models describe the current growth rate. These models are good tools for growth prediction in the near future and will be compareable with further models; they will demonstrate ...the Norway spruce growth changes considering the climate change.
Tree growth depends on genetic, climatic, microsite conditions and stand structure variations. A new evaluation method was carried out for studying mutual tree competition based on the social area of each trees. Nine Norway spruce (
Picea abies
(L.) Karst.) stands were investigated. The objectives of this study were to quantify each individual tree basal area increment during the years 2008–2012 with respect to the social area of the individual trees, competition indexes and the dendrometric characteristics of the trees. The social area of the trees in the investigated plots varied from 0.06 to 43.04 m
2
where correlation coefficient (
R
2
) with each individual basal area increment was significantly high. Distance characteristics e.g. minimum weighted distance (
D
i
min
) and maximum weighted distance (
D
i
max
) provided a correlation coefficient (with individual tree basal area increments) varying from 0.69 to 0.84. Values of the
R
2
between individual basal area increments and nearest trees dependent (NTD
6
) competition indexes varied from 0.41 to 0.66, while for distance-dependent competition indexes it varied from 0.59 to 0.78. To facilitate 5-year individual basal area increment inventories (
I
g5
), linear models were used to develop the new specific functions. Individual tree growth models based on the distance measurement components and their combinations resulted in very high estimation accuracy. Therefore, the best model to determining basal area increment is the proven linear model using a social tree area, stem diameter at the breast height and crown length as input variables.
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