28,130 research outputs found

    Ecological study of Betula pendula stands in Hyrcanian forests, North Iran

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    This study was carried out in the rocky forests of Dodangeh, south of Sari, an area extended as a narrow strip from east to west in the heights of Hyrcanian forests, with the area of ca 2,000 ha and the altitude of 2,500-2,950 m a.s.l. Regarding vegetation history, Dodangeh is a refuge for Betula pendula Roth. This species together with Corylus avellana L. are the first ones formed a plant community in Hyrcanian region since the glaciation of the Tertiary period and gradual retrogression of conifers. A number of 181 plant species belonging to 52 families were identified through sampling of 20 relevés of the size 400 m2. Out of these, 17% were endemic of Hyrcanian and Irano-Turanian regions including four species viz. Aconitum iranshahrii Renz., Cortusa mathioli subsp. iranica, Delphinium elbursense var. elbursense and Doronicum wendelboii which could be found nowhere else in the world. Querco macrantherae-Betuletum pendulae association is recorded in the Hyrcanian and Euro-Siberian regions for the first time. Chorological studies of Querco macrantherae-Betuletum pendulae showed that the elements of Irano-Turanian, Euro-Siberian and Hyrcanian regions are more than those of the other existing vegetational regions in the area. Dynamic processes of this association and its restoration were also considered in the study

    Urbanised forested landscape: Urbanisation, timber extraction and forest care on the Vi»ôeu Valley, northern Romania

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    By looking at urbanisation processes from the vantage point of the forest, and the ways in which it both constitutes our living space while having been separated from the bounded space of the urban in modern history, the thesis asks: How can we (re)imagine urbanisation beyond the limits of the urban? How can a feminine line of thinking engage with the forest beyond the capitalist-colonial paradigm and its extractive project? and How can we ‚Äúthink with care‚ÄĚ (Puig de la Bellacasa 2017) towards the forest as an inhabitant of our common world, instead of perpetuating the image of the forest as a space outside the delimited boundaries of the city? Through a case study research, introducing the Vi»ôeu Valley in northern Romania as both a site engaged in the circulation of the global timber flow, a part of what Brenner and Schmid (2014) name ‚Äúplanetary urbanisation‚ÄĚ, where the extractive logging operations beginning in the late XVIIIth century have constructed it as an extractive landscape, and a more than human landscape inhabited by a multitude of beings (animal, plant, and human) the thesis argues towards the importance of forest care and indigenous knowledge in landscape management understood as a trans-generational transmission of knowledge, that is interdependent with the persistence of the landscape as such. Having a trans-scalar approach, the thesis investigates the ways in which the extractive projects of the capitalist-colonial paradigm have and still are shaping forested landscapes across the globe in order to situate the case as part of a planetary forest landscape and the contemporary debates it is engaged in. By engaging with emerging paradigms within the fields of plant communication, forestry, legal scholarship and landscape urbanism that present trees and forests as intelligent beings, and look at urbanisation as a way of inhabiting the landscape in both indigenous and modern cultures, the thesis argues towards viewing forested landscapes as more than human living spaces. Thinking urbanisation through the case of the Vi»ôeu Valley‚Äôs urbanised forested landscape, the thesis aligns with alternate ways of viewing urbanisation as co-habitation with more than human beings, particularly those emerging from interdisciplinary research in the Amazon river basin (Tavares 2017, Heckenberger 2012) and, in light of emerging discourses on the rights of nature, proposes an expanded concept of planetary citizenship, to include non-human personhood

    Social plasticity and limited resilience of coral-dwelling gobies (genus Gobiodon) to climate change: outlook for coral-fish mutualisms in a changing world

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    Climate change is rapidly altering ecosystems on a global scale, and coral reefs are particularly vulnerable to climate-induced disturbances. Coral reefs depend on mutualisms with their foundation species, i.e. corals, and yet most of the literature has focused on their mutualisms with only one type of symbiont (algae). Little is known about how coral-fish mutualisms respond to climatic disturbances, and yet cyclones and heatwaves are increasingly devastating coral reefs. We urgently need to assess how coral-fish mutualisms respond to disturbances as changes in mutualisms have the potential for causing ecosystem-level changes. Yet fish in coral-fish mutualisms have often been overlooked in studies regarding environmental disturbances. There are multiple aspects of the life history, behaviour, and movement of fish that may impact their mutualisms with corals. Here, I investigated (1) whether both symbionts in coral-fish mutualisms respond similarly to climatic disturbances, and (2) what mechanisms from the fish perspective are likely responsible for how coral-fish mutualisms respond to climatic disturbances. I used a model coral-fish mutualism between coral hosts from the genus Acropora and coral-dwelling gobies from the genus Gobiodon in which both organisms provide important benefits for the resilience of each partner. I implemented a comparative approach by investigating multiple goby and coral species encountered in study locations to provide genus-wide understandings of how their coral-goby mutualisms are impacted by climatic disturbances. Particularly important is that gobies can live in social groups and living in groups can improve coral maintenance. Accordingly, first I provided a comprehensive review on how climate change is impacting the sociality of coral reef fish as the sociality of these taxa have only recently been investigated. Studies have shown that climate change affected the habitat and physiology of fishes, and each of these effects impacted their sociality. The review highlighted key changes to the sociality of these fish depending on how corals respond to disturbances, like reduction in coral size, shifts in coral communities, and health of corals. Secondly, I set the scene by monitoring coral-goby mutualisms throughout four extreme disturbances in the northern Great Barrier Reef (GBR): two cyclones and two heatwaves that caused mass bleaching events. In the aftermath and after a few years of recovery, there were more coral species, but corals were almost three times smaller. For gobies though, there were two times fewer coral species, there were fewer gobies, and most corals became absent of gobies when previously most were occupied. Alarmingly, this study highlighted that gobies declined far more than corals and were far slower to recover than their hosts. Finally, I used a combination of observational and manipulative studies to investigate the potential for coral gobies to exhibit plasticity in their host use, sociality, and movement in relation to disturbances. Following the same four extreme disturbances, I found that gobies shifted hosts to the newly abundant coral species. Although exhibiting host plasticity may be an advantage in the short-term, using alternative coral hosts may reduce the fitness of gobies, i.e. their growth rates. I then investigated whether gobies shifted their social tendencies to live in groups or in pairs following these four extreme disturbances in the northern GBR and following a single extreme disturbance in the southern GBR. Gobies no longer lived in groups, rarely in pairs, and primarily lived as solitary individuals after the four disturbances, whereas there was relatively little change in their social tendencies after the single disturbance. This study suggests that if consecutive disturbances become the norm, gobies may continue to decline if they primarily stay solitary as they need to live in pairs to breed. I then completed another study to investigate how predation risk, coral size and health, and number of group members affected the movement of gobies. I translocated gobies in situ into corals with varying sizes, number of individuals, and health. I replicated the study in a relatively undisturbed environment in Papua New Guinea, and in the highly disturbed environment following the four extreme disturbances in northern GBR. Regardless of the disturbance state, gobies preferred to face high costs of predation and did alter their movement based on coral size, health, or number of group members, even when predation risk was higher in disturbed environments. This suggests that gobies do not alter their movement plasticity based on environmental disturbances even though predation risk is heightened. This means that gobies exhibited host and social plasticity, but they did not exhibit movement plasticity to disturbances. I found that each mechanism of plasticity was likely responsible for a reduced recovery potential of gobies compared to their coral hosts. By combining the findings from each chapter of the thesis, I suggest that coral-fish mutualisms are highly vulnerable to climate change as fish experience barriers to recovery via host, social, and movement plasticity. Future conservation strategies should address declines in fish in order to maintain coral-fish mutualisms important for coral health

    New insights on stomata analysis of European conifers 65 years after the pioneering study of Werner Trautmann (1953)

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    Conifer-stomata analysis is an essential part of the palaeoecological toolbox because it allows the determination of the local presence of plant populations with a lower degree of uncertainty than pollen analysis. Although the European postglacial pool of conifer taxa is broad, stomata morphologies for only few taxa have been investigated. Prior stomata morphology studies focused on taxa having wide distribution ranges in central and northern Europe, and stomata morphologies for taxa occurring in southern European and Northern African mountain regions have not yet been described. Here, we present a qualitative assessment of stomata morphologies for 40 taxa from eight genera (Cupressus, Juniperus, Abies, Cedrus, Larix, Picea, Pinus and Taxus) that are present on the European continent and the southern borderlands of the Mediterranean Basin, thereby broadening substantially both the regional and taxonomical coverage of this now 65-years old technique. We found that visual identification of conifer stomata does not allow species-level identifications, supporting the notion of genus-specific stomata morphologies found in prior studies. For each genus, we describe the stomata morphologies taking into account the varying shape of stomata features at different focusing levels. In addition, we provide stop-motion animations (publicly available at http://dx.doi.org/10.6084/m9.figshare.7165261) that may be useful tools for microscope analysts who wish to acquaint themselves with conifer-stomata analysis

    Can clinician’s risk assessments distinguish those who disclose suicidal ideation from those who attempt suicide?

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    Participants were 85 individuals who made suicide attempts within two years of their Improving Access to Psychological Therapies (IAPT) assessment, identified using record linkage. Two comparison groups, non-suicidal controls (n‚ÄČ=‚ÄČ1416) and (ideators, n‚ÄČ=‚ÄČ743) were compared on variables extracted from the standardized IAPT risk assessment interview. Disclosure of a historical suicide attempt or non-suicidal self-injury (NSSI) distinguished those making an attempt from those with suicidal ideation only, but suicidal intent did not. A third of the participants concealed a historical suicide attempt. The IAPT Phobia Scale classified 49.30% of attempters with 100% specificity. The IAPT Phobia Scale may have clinical value in assessing risk but requires validation. Past suicide attempt and NSSI have better clinical risk assessment utility than current suicidal ideation intensity. Risk assessment relying on disclosure is likely to be flawed and risks support being withheld from those assumed to be at lower risk

    First records of Sirococcus conigenus causing shoot blight on Pinus peuce in Bulgaria

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    Macedonian pine (Pinus peuce) is a southern Balkan Peninsula endemic, growing in high mountains of Bulgaria, between 1400 and 2100 m a.s.l. Stands of P. peuce form the upper tree line forest areas. During a survey in 2020-2022 on Macedonian pine natural stands and plantations in Bulgaria, symptoms of shoot blight were observed in the Pirin Mts, the Rila Mts and Mt Vitosha. The fungal pathogen Sirococcus conigenus was identified as the causal agent of the disease that appeared for the first time on Pinus peuce in Bulgaria and Balkan Peninsula. Incidence of blighted shoots on individual trees varied, but was as high as 70-80% in the Rila Mts and Mt Vitosha

    Detection of susceptible Norway spruce to bark beetle attack using PlanetScope multispectral imagery

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    Climate change-related acute or long-term drought stress can weaken forest ecosystems and result in widespread bark beetle infestations. Eurasian spruce bark beetle (Ips typographus L.) infestations have been occurring in Norway spruce [Picea abies (L.) Karst.]-dominated forests in central Europe including the Czechia. These infestations appear regularly, especially in homogeneous spruce stands, and the impact varies with the climate-induced water stress conditions. The removal of infected trees before the beetles leave the bark is an important step in forest pest management. Early identification of susceptible trees to infestations is also very important but quite challenging since stressed tree-tops show no sign of discolouration in the visible spectrum. We investigated if individual spectral bandwidths or developed spectral vegetation indices (SVIs), can be used to differentiate non-attacked trees, assumed to be healthy, from trees susceptible to attacks in the later stages of a growing season. And, how the temporal-scale patterns of individual bands and developed SVIs of susceptible trees to attacks, driven by changes in spectral characteristics of trees, behave differently than those patterns observed for healthy trees. The multispectral imagery from the PlanetScope satellite coupled with field data were used to statistically test the competency of the individual band and/or developed SVIs to differentiate two designated classes of healthy and susceptible trees. We found significant differences between SVIs of the susceptible and healthy spruce forests using the Enhanced Vegetation Index (EVI) and Visible Atmospherically Resistant Index (VARI). The accuracy for both indices ranged from 0.7 to 0.78; the highest among all examined indices. The results indicated that the spectral differences between the healthy and susceptible trees were present at the beginning of the growing season before the attacks. The existing spectral differences, likely caused by water-stress stimuli such as droughts, may be a key to detecting forests susceptible to early infestations. Our introduced methodology can also be applied in future research, using new generations of the PlanetScope imagery, to assess forests susceptibility to bark beetle infestations early in the growing season

    Spatial analysis of tree species before forest fires

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    Spain is included in the top five European countries with the highest number of wildfires. The occurrence and magnitude of forest fires involves aspects of a very diverse nature, from those of a socio-economic, climatic, or physiographic nature, to those concerning fuel or the availability and quantity of resources and means of extinction. The distribution of wildfires in Galicia is not random and that fire occurrence may depend on ownership conflicts also a spatial dependence between productive or non-productive area exists. Satellite data play a major role in providing knowledge about fires by delivering rapid information to map fire-damaged areas precisely and promptly. In addition, the availability of large-scale data and the high temporal resolution offered by the Sentinel-2 satellite enables to classify and determine the land cover changes with high accuracy. This study describes a methodology to detect burned areas and analyse the Land Cover and Land Use (LCLU) classes present in these areas during the period of 5 years (2016‚Äď2021) by Sentinel-2 images. The training areas were obtained by photointerpretation and the image classification was performed using the Random Forest algorithm which shows an overall accuracy range between 80‚Äď85%. The methodology concluded that Lobios and Mui√Īos were the most affected municipalities by wildfires. Additionally, the spatial analysis determined that the Deciduous Forest mainly composed by Quercus sp. were the most affected in 2017 followed by Coniferous Forest mainly composed by Pinus sp.in 2016. Although, Scrub and Rock are the classes more affected for wildfire during 2016‚Äď2020 period.Universidade de Vigo | Ref. 00VI 131H 6410211Agencia Estatal de Investigaci√≥n | Ref. PCI2020-120705-2Xunta de Galicia | Ref. ED481B-2019-061Xunta de Galicia | Ref. ED431C 2020/0

    Negative effects of urbanisation on diurnal and nocturnal pollen‚Äźtransport networks

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    Pollinating insects are declining due to habitat loss and climate change, and cities with limited habitat and floral resources may be particularly vulnerable. The effects of urban landscapes on pollination networks remain poorly understood, and comparative studies of taxa with divergent niches are lacking. Here, for the first time, we simultaneously compare nocturnal moth and diurnal bee pollen-transport networks using DNA metabarcoding and ask how pollination networks are affected by increasing urbanisation. Bees and moths exhibited substantial divergence in the communities of plants they interact with. Increasing urbanisation had comparable negative effects on pollen-transport networks of both taxa, with significant declines in pollen species richness. We show that moths are an important, but overlooked, component of urban pollen-transport networks for wild flowering plants, horticultural crops, and trees. Our findings highlight the need to include both bee and non-bee taxa when assessing the status of critical plant-insect interactions in urbanised landscapes
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