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Chronosequence Resampling Elucidates Tree Community and Forest Structure Recovery Patterns in Restored Tropical Rainforest
Get PDFForest restoration is an essential tool for conserving biodiversity in tropical regions; yet, restoration outcomes in the Afrotropics remain largely understudied. Here, we investigated how the forest structure, tree diversity, community, life-history traits and habitat associations recovered over three decades of active restoration in an East African rainforest in Uganda. The vegetation surveys were initially conducted in 2013 and repeated in 2021. Altogether, the study included 45 actively restored forest sites (aged 4-26 years) and 10 primary forest reference sites. The results showed increased tree taxa richness, basal area, tree height and community similarity (i.e., the similarity of community composition of restored forests to the composition of primary forest) along the age gradient. After 20 years of planting, Simpson's diversity and canopy cover reached similar values recorded in the reference primary forest. In contrast, restored forests had not attained levels of tree taxa richness, basal area, stem density, or community similarity comparable to those of the reference primary forest within three decades. We found an age gradient from younger restored to older restored to the primary forest in the composition of tree communities. The proportion of species with animal-dispersed seeds was similar in the restored and the primary forest. The proportion of shade-tolerant and forest-interior species had increased along the age gradient in the 2021 survey. In conclusion, forest structure, diversity and community showed early signs of recovery, but the rate of change slowed over time
Assessing the cues required for mate choice copying in the plainfin midshipman fish
Get PDFWhen choosing a mate, females can rely on their own judgements of male quality or use social information from other females'choices. The use of social information to inform mating decisions is called mate choice copying. Theory predicts that mate choice copying should be strongest in species where females have few mates over the course of their life span because each mating constitutes a greater proportion of the female's expected reproductive value; however, most research on mate choice copying has thus far focused on species with highly promiscuous females. In this study, we use the plainfin midshipman, Porichthys notatus, a toadfish in which females typically choose one mate per year, to investigate whether females mate-choice copy and, if they do, which cues influence their decision making. We show that in the wild, plainfin midshipman females co-occur in nests more often than expected under random female choice. Additionally, we found that females in the laboratory did not base their mating decisions on the mere presence of another female or previously laid eggs; however, females were more likely to choose a male they had observed spawning with another female. Taken together, our results indicate that female plainfin midshipman do mate-choice copy, but only when they observe a spawning event. Understanding how different mating systems affect the strength of mate choice copying and which cues are necessary to elicit mate choice copying will help elucidate more broadly how this behaviour evolved and is maintained. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/)
Limited resource use overlaps among small pelagic fish species in the central Baltic Sea
Get PDFSmall pelagic fish have a central position in pelagic food webs, linking plankton production to higher trophic levels. They often favour crustacean mesozooplankton and are thought to compete for the same resource, an assumption that relies on microscopy diet identification that neglects digested and soft-bodied prey. Here, we aimed to systematically identify the entire resource use and overlap among the dominant small pelagic fish in the central Baltic Sea at high taxonomy resolution. The diet composition of two clupeid species, herring (Clupea harengus) and sprat (Sprattus sprattus), and the three-spined stickleback (Gasterosteus aculeatus) was assessed in May and October using DNA metabarcoding, stable isotopes, and microscopy. All three methods gave consistent results. The clupeids shared a similar diet in May when prey diversity was low, composed mainly of the copepods Pseudocalanus and Acartia, whereas three-spined stickleback favoured different copepod species and the rotifer Synchaeta, which was confirmed by a different isotopic value as compared to the two clupeids. In October, all forage fish preyed on diverse zooplankton species, mainly composed of the copepods Acartia, Eurytemora, and Temora, while Pseudocalanus was only important for herring. The observed resource use partitioning between sprat and herring was confirmed by the stable isotope values from October, suggesting that different prey species were targeted during the summer period. Our study highlights that resource use overlaps among small pelagic fish were limited and varied with prey availability. This suggests that shifts in zooplankton dynamics, rather than competition for resources, have the potential to drive small pelagic fish population fluctuations
Human-mediated introgression and Varroa destructor shaped the genetic structure of honey bee populations in the Azores
Get PDFThe evolutionary trajectory of island populations can be rapidly altered by human-mediated migration, a process further exacerbated when immigrants introduce invasive parasites, creating new selective pressures. Using customised SNP panels constructed with genome-wide diagnostic loci, we describe the genetic changes in honey bee populations inhabiting the Azores archipelago. As part of a breeding initiative in the 1980s, these populations were recurrently exposed to beekeeper-mediated gene flow from a highly divergent commercial line (C lineage) until the arrival of the Varroa mite to the Azores in 2000, which prompted a honey bee importation ban. Admixture analysis revealed a spatially heterogeneous introgression landscape in the Azores. Four of the five mite-free islands (Santa Maria, S & atilde;o Miguel, Terceira, and S & atilde;o Jorge) presented negligible levels of C-lineage introgression (mean Q-value: 0.004-0.091) despite repeated C-lineage importations in the past. In contrast, the three mite-infested islands (Pico, Faial, and Flores) presented high levels of introgression (mean Q-value: 0.156-0.261). The mite-free island of Graciosa harboured the most admixed population (mean Q-value: 0.392), which is consistent with efforts to eradicate the historical population and replace it with C-lineage honey bees during the implementation of the breeding program. Bayesian inference modelling indicated that the presence of a C-lineage maternal origin and Varroa were associated with increased introgression proportions (100% posterior probability), increasing the mean Q-value by 0.049 and 0.118, respectively. Our findings indicate that these anthropogenic processes altered the historically introduced gene pool and provide a foundation for developing effective conservation strategies to protect honey bees in the Azores
34th Annual Report 2025
Get PDFThe Integrated Monitoring Programme (ICP IM) is part of the effect-oriented activities under the 1979 Convention on Long-range Transboundary Air Pollution, which covers the region of the United Nations Economic Commission for Europe (UNECE). The main aim of the ICP IM is to provide a framework to observe and understand the complex changes occurring in natural/semi natural ecosystems. This report summarizes the work carried out by the ICP IM Programme Centre and several collaborating institutes, including:• A short summary of previous data assessments• A status report of the ICP IM activities, content of the IM database, and geographical coverage of the monitoring network• A report on long-term trends in precipitation, throughfall and runoff water chemistry at IM sites• Analysis of changes in above ground carbon pools at the heavily disturbed IM site Aneboda (Sweden)• National Reports on ICP IM activitie
Exploration of the functions and potentials of urban forest gardens in Sweden
Get PDFForest gardens are multilayered intercropped systems with perennial and mainly, edible crops. They have recently begun to be regarded as edible green infrastructure of cities in temperate regions. This study was aimed at: i) making a national inventory of Swedish urban forest gardens, ii) identifying the drivers that led to their establishment and iii) understanding their contribution to urban sustainability policies. A total of 30 forest gardens were identified in 10 different cities. Site visits and interviews to relevant stakeholders, highlighted the presence of three main types of origin of forest gardens initiated firstly by grassroot movements, followed by schools and municipal officials. These actors were informed and trained by so-called knowledge hubs, namely associations, education centres and professionals. A social network analysis emphasized that knowledge hubs were pivotal in supporting the establishment of forest gardens and circulate information, whilst few connections were found among other actors. More collaboration and integration among all stakeholders might be a key factor to increase the number of forest gardens and improve their quality. Stakeholders stressed the prominence of cultural ecosystems services provided by urban forest gardens by assigning high scores to education, enhancement of community building, recreation and aesthetic values (8.7/10) as compared with regulating services such as biodiversity and climate regulation (7.9/10) and provisioning services (6.5/10). Urban forest gardens were acknowledged to actively engage citizens in public green spaces management and planning, to improve environmental awareness and to promote intergenerational connections. However, the interviews underlined also the presence of legal burdens on land management and use, financial sustainability of both bottom-up and top-down forest gardens and lack of skilled labour. This study offers guidance to urban planners, public officials, education centres and activists on how highly multifunctional forest gardens could improve the green infrastructure thus contributing to cities' sustainability
Phytochrome B and phytochrome-interacting-factor4 modulate tree seasonal growth in cold environments
Get PDFPlants that live at high latitudes and altitudes must adapt to growth in cold environments. Trees survive freezing winter conditions by ceasing growth and forming protective winter buds at the end of the growing season. To optimize growth and adaptation, the timing of growth cessation and bud set is critical. Like the well-studied Populus species (poplars, aspens, cottonwoods), many trees respond to the shortening photoperiods of fall to induce growth cessation. Temperature also has a role in this process, but the mechanism is unknown. Here, we show that the PHYTOCHROME B (PHYB)-PHYTOCHROME INTERACTING FACTOR4 (PIF4) module controls the interplay between photoperiod cues and temperature to prevent premature growth cessation and bud set at cooler temperatures. PHYB is essential for the ability of aspen trees to maintain growth under lower temperatures in permissive long days. This is mediated through PIF4, which promotes growth cessation, specifically in response to low temperatures rather than to changes in photoperiod. PIF4 can directly bind to the promoter region of the vegetative growth marker gene FLOWERING LOCUS T2 (FT2). In contrast to annual plants, it does so to suppress its transcription. Furthermore, lower temperatures can suppress PIF4 function at the transcriptional and protein levels to prevent premature growth cessation. These data show how poplar trees balance the antagonistic roles of PHYB and PIF4 to optimise the timing of growth cessation and bud set in cold environments, and this has been achieved with contrasting mechanisms compared to the annual plant model
Long-Term System Suitability Evaluation for Mass Accuracy in the Analysis of Small Molecules by High-Resolution Mass Spectrometry
Get PDFHigh-resolution mass spectrometry (HRMS) is critical for the identification and characterization of (un)known organic chemicals. In this regard, ensuring high mass accuracy in HRMS instruments is essential for reliable results in nontarget and suspect screening. This study presents a practical approach for evaluating and maintaining mass accuracy over time using ultrahigh pressure liquid chromatography coupled with electrospray ionization Orbitrap HRMS. A set of 13 reference standards, encompassing a range of polarities and chemical families, was analyzed before and after sample analysis batches to assess the impact of various factors on the instrumental performance regarding mass accuracy. The aim is not to recalibrate the system but to provide a reliable snapshot of the mass accuracy over time. The study found that the positive ionization mode exhibited higher accuracy and precision compared with the negative mode. Factors affecting mass accuracy included calibration quality, the number of batch injections, and the time between calibrations, where the two latter factors were related to each other. Results suggest that performing system suitability tests for high-resolution accurate masses with two injections before and after sample analysis is adequate for ensuring acceptable mass spectrometric performance for robust and reliable HRMS data acquisition, but performing three injections is recommended. This protocol ensures that informed decisions can be made with regard to the mass accuracy, the calibration, and a potential recalibration before HRMS data acquisition is performed
Organic nitrogen
Get PDFNitrogen (N) is an essential nutrient for plant growth and development. While research has traditionally focused on inorganic N forms, such as nitrate and ammonium, organic N forms, including amino acids, have also been detected in the soil. Notably, plants were shown to take up organic N forms and utilize them as an alternative N source. These findings highlight the significance of organic N nutrition. However, most current knowledge on N uptake mechanisms and N starvation responses is derived from studies on inorganic N. This has left substantial gaps in our understanding of how plants acquire and respond to organic N. The work presented in this thesis addresses some of these gaps by investigating the physiological effects of amino acid nutrition and the molecular regulation of amino acid uptake in Arabidopsis thaliana. The results reveal a distinct organic N-specific root phenotype and show that plants supplied solely with the amino acid glutamine (L-gln) are not N-starved. The second part of the thesis investigates the regulation of the amino acid uptake by focusing on the high-affinity transporter LHT1 (LYSINE HISTIDINE TRANSPORTER 1). Experiments identify the CALCIUM DEPENDENT KINASE1 (CPK1) as an interaction partner of LHT1, suggesting a post-translational regulation of the transporter. Interestingly, uptake assays show that CPK1 negatively influences the amino acid uptake. Further experiments confirmed a negative regulatory effect of CPK1 on LHT1 transport activity. To investigate the role of phosphorylation in regulating LHT1, phospho-mutants of the transporter were generated and analyzed. Two potential phosphorylation sites were identified, with Thr151 being identified as a potential CPK1 target site. This thesis enhances our understanding of how plants respond to organic N and provides deeper insights into amino acid uptake, with a particular focus on the LHT1 transport regulation