Biology subjects

Deak, B.

Publications and source records attributed to Deak, B..

13 recordsLinked to original sources

bioRxiv2025

On the edge of extinction: Delayed plant genetic response to forest edge dynamics

Understanding genetic responses to forest dynamics is essential for predicting the long-term viability of understory plant populations and for developing effective conservation strategies. This study investigates genetic extinction debt and colonization credit in Circaea lutetiana, a clonal forest understory species, across its European range. Using pooled genotype-by-sequencing data from 40 forest edge and core populations, we examined to what extent population size, latitude and historical changes in forest configuration predict genetic diversity. Our findings reveal that the historical forest configuration profoundly shapes present-day genetic diversity. Long-established forest edge populations exhibit significantly reduced allelic richness (-9%) compared to core populations, indicating the partial pay-off of a genetic extinction debt. In contrast, populations from recently established forest edges maintain comparable allelic richness to core populations, suggesting delayed population genetic responses to land use changes. Finally, populations established in areas that were afforested during the past 250 years exhibit lower genetic diversity than historical forest core populations, indicating a delay in genetic recovery and thus a potential genetic colonization credit. Our results highlight that C. lutetiana populations are not at equilibrium with the current forest configuration, underscoring the role of lagged genetic responses across very long time scales. Connectivity and population size further moderate genetic diversity, with smaller, isolated populations particularly vulnerable to genetic erosion. Given the limited research on delayed evolution in forest understory species, our results improve the understanding of extinction risk dynamics and underscore the need for history-informed restoration efforts.

ecology↗

bioRxiv2025

Small grassland patches are hotspots for medicinal plants and associated phytochemical diversity in European agricultural landscapes

O_LIMedicinal plants are threatened by overcollection and habitat loss due to human activities. In this study, we aimed to reveal how ancient earthen burial mounds covered with successional grasslands of different ages can contribute to conservation of medicinal plants and related phytochemical diversity in European agricultural landscapes. C_LIO_LIUsing vegetation data collected from 166 mounds in Hungary, we identified the medicinal plant species present at these sites, and based on multiple literature sources, provided the secondary metabolite profiles of the medicinal plants and plant communities. By using generalized linear mixed models and redundancy analysis we investigated how the age of the vegetation, percentage of croplands around the sites, site area, and soil properties influence the diversity of medicinal plants and associated phytochemicals. C_LIO_LIWe found that mounds provide safe havens for a wide range of medicinal plants and secondary metabolites. Our results showed that grassland-related medicinal plants producing iridoids and diterpenes were typical on mounds with older grasslands. A large proportion of croplands in the neighboring landscape and high soil pH supported generalist medicinal plants producing nitrogen-containing and sesquiterpene related secondary metabolites. Higher soil nitrogen, phosphorus, and potassium content favored medicinal plants producing lignans, glycosides, and organic acids. C_LIO_LIOur results suggest that the high phytochemical diversity is supported by the occurrence of various compounds facilitating the adaptation of medicinal plants to the various environmental stressors and biotic factors, such as competition, herbivory and pathogens, present in sites embedded in agricultural landscapes. C_LI Societal Impact StatementBesides being important components of landscape-level biodiversity, medicinal plants are essential resources for traditional and modern healthcare. However, in parallel with biodiversity loss driven by human activities, populations of medicinal plants have also declined. By maintaining connections between nature, culture, and people, sacred natural sites can help counteract this trend. We studied the potential of ancient burial mounds to maintain populations of medicinal plants and related phytochemical diversity in European agricultural landscapes. Our findings highlight the importance of conserving grassland vegetation and associated biodiversity at these sites, which is crucial for preserving a key ecosystem service in intensively managed landscapes.

ecology↗

bioRxiv2024

Effect of pre-germination temperature conditions on germination characteristics of temperate grassland species

Germination characteristics of target species used for grassland restoration are often unknown, despite such information would be essential for designing restoration interventions. Filling this knowledge gap and improving our understanding about germination responses of grassland species to varying cold and warm treatments could be especially important in the face of climate change. Here we studied the effect of three different durations of warm dry stratification and three different durations of cold wet stratification, and their combinations in a full factorial design (in total 15 different pre-germination treatments), on the germination capacity of 48 grassland species native to Central Europe. Stratification treatments modelled present and forecasted summer (1-3 months warm period) and winter (1-3 months cold period) temperature conditions, while the study of the combined effect of these treatments is especially important in spring-germinating species. As response variables, we calculated relative response indexes and germination uncertainties of each species separately and applied general linear models to study the effect of treatments on these variables. We found clear effect of warm- or cold stratification on relative response indexes only in four species: strong positive response to warm stratification was found in Silene conica, while strong positive response to cold stratification was found in Agrimonia eupatoria, Echium vulgare, and Plantago lanceolata. The responses to treatment combinations were contradictory or lacked clear trends in most of the species. Germination uncertainty in general was high for all species, supporting the fact that Central European grassland species often rely on bet hedging as risk spreading strategy, to avoid unfavourable conditions during seedling establishment.

plant biology↗

bioRxiv2022

Heritage of ancient cultures supports conservation: a continent-wide perspective from the Eurasian steppes

Civilisations including ancient ones, have shaped the global ecosystems in many ways through a co-evolution of landscapes and humans. However, the cultural legacies of ancient and lost civilisations are seldom considered in conservation. Here using a continental-scale dataset containing over 1,000 data records on the localities, land cover, protection status and cultural values related to ancient steppic burial mounds (so-called kurgans), we evaluated how these iconic and widespread landmarks can contribute to grassland conservation in the Eurasian steppes, which is one of the most endangered biomes on Earth. By using Bayesian logistic generalized regressions and proportional odds logistic regressions, we aimed to reveal the potential of mounds in preserving grasslands considering landscapes with different levels of land use transformation. We also compared the conservation potential of mounds situated inside and outside protected areas and assessed whether the presence of cultural, historical or spiritual values support the maintenance of grasslands on them. We revealed that kurgans have enormous importance in preserving grasslands in transformed landscapes outside protected areas, where they can act as habitat islands, and provide an additional pillar for conservation by contributing to habitat conservation and improvement of habitat connectivity. We found that besides their steep slopes hindering ploughing, the existence of cultural, historical or religious values could almost double the chance for grassland occurrence on kurgans due to the related extensive land use and the respect of local communities. As the estimated number of steppic mounds is about 600,000 and also similar historical features exist in all continents, our results can be upscaled to a global level. Our results also suggest that an integrative socio-ecological approach in conservation might support the positive synergistic effects of conservational, landscape and cultural values.

ecology↗

bioRxiv2021

Individually Unique Dynamics of Cortical Connectivity Reflect the Ongoing Intensity of Chronic Pain

BackgroundChronic pain diseases are characterised by an ongoing and fluctuating endogenous pain, yet it remains to be elucidated how this is reflected by the dynamics of ongoing functional cortical connections. The present study addresses this disparity by taking the individual perspective of pain patients into account, which is the varying intensity of endogenous pain. MethodsTo this end, we investigated the cortical encoding of 20 chronic back pain patients and 20 chronic migraineurs in four repeated fMRI sessions. During the recording, the patients were asked to continuously rate their pain intensity. A brain parcellation approach subdivided the whole brain into 408 regions. A 10 s sliding-window connectivity analysis computed the pair-wise and time-varying connectivity between all brain regions across the entire recording period. Linear mixed effects models were fitted for each pair of brain regions to explore the relationship between cortical connectivity and the observed trajectory of the patients fluctuating endogenous pain. ResultsTwo pain processing entities were taken into account: pain intensity (high, middle, low pain) and the direction of pain intensity changes (rising vs. falling pain). Overall, we found that periods of high and increasing pain were predominantly related to low cortical connectivity. For chronic back pain this applies to the pain intensity-related connectivity for limbic and cingulate areas, and for the precuneus. The change of pain intensity was subserved by connections in left parietal opercular regions, right insular regions, as well as large parts of the parietal, cingular and motor cortices. The change of pain intensity direction in chronic migraine was reflected by decreasing connectivity between the anterior insular cortex and orbitofrontal areas, as well as between the PCC and frontal and ACC regions. ConclusionsInterestingly, the group results were not mirrored by the individual patterns of pain-related connectivity, which is suggested to deny the idea of a common neuronal core problem for chronic pain diseases. In a similar vein, our findings are supported by the experience of clinicians, who encounter patients with a unique composition of characteristics: personality traits, various combinations of symptoms, and a wide range of individual responses to treatment. The diversity of the individual cortical signatures of chronic pain encoding results adds to the understanding of chronic pain as a complex and multifaceted disease. The present findings support recent developments for more personalised medicine.

neuroscience↗

bioRxiv2021

Intrinsic Network Activity Reflects the Fluctuating Experience of Tonic Pain

Although we know sensation is continuous, research on long-lasting and continuously changing stimuli is scarce and the dynamic nature of ongoing cortical processing is largely neglected. In a longitudinal study with 152 fMRI sessions, participants were asked to continuously rate the intensity of applied tonic heat pain for 20 minutes. Using group independent component analysis and dual-regression, we extracted the subjects time courses of intrinsic network activity. The relationship between the dynamic fluctuation of network activity with the varying time courses of three pain processing entities was computed: pain intensity, the direction of pain intensity changes and temperature. We were able to dissociate the spatio-temporal patterns of objective (temperature) and subjective (pain intensity/changes of pain intensity) aspects of pain processing in the human brain. We found two somatosensory networks with distinct functions: one network which encodes the small fluctuations in temperature and consists mainly of bilateral SI. A second right-lateralised network that encodes the intensity of the subjective experience of pain consists of SI, SII, the PCC, and the thalamus. We revealed the somatosensory dynamics that build up towards a current subjective percept of pain. The timing suggests a cascade of subsequent processing steps towards the current pain percept.

neuroscience↗

bioRxiv2021

Intrinsic Network Activity Reflects the Ongoing Experience of Chronic Pain

Analyses of intrinsic network activity have been instrumental in revealing cortical processes that are altered in chronic pain patients. However, such studies have not accounted for variable time courses of network activity and subjective pain experience. In a novel approach, we aimed to elucidate how intrinsic functional networks evolve in regard to the fluctuating intensity of the experience of chronic pain. In a longitudinal study with 156 fMRI sessions, 20 chronic back pain patients and 20 chronic migraine patients were asked to continuously rate the intensity of their endogenous pain. Using group independent component analysis and dual-regression, we extracted the time courses of 100 independent components separately for chronic back pain and chronic migraine. We investigated the relationship between the fluctuation of intrinsic network activity with the time course of subjective pain ratings. For chronic back pain, we found increased cortical network activity for the salience network and a local pontine network, as well as decreased network activity in the anterior and posterior default mode network for higher pain intensities. Higher pain intensities in chronic migraine were accompanied with lower activity in a prefrontal cortical network. By taking the perspective of the individual, we focused on the processes that matter for each patient, which are phases of relatively low pain and more straining phases of relatively high pain. The present design of ongoing assessment of the endogenous pain can be a powerful and promising tool to assess the signature of a patients endogenous pain encoding over weeks and months.

neuroscience↗

bioRxiv2020

Decreased calmodulin recruitment triggers PMCA4 dysfunction and pancreatic injury in cystic fibrosis

Exocrine pancreatic damage is a common complication of cystic fibrosis (CF), which can significantly debilitate the quality of life and life expectancy of CF patients. The cystic fibrosis transmembrane conductance regulator (CFTR) has a major role in pancreatic ductal ion secretion, however, it presumably has an influence on intracellular signaling as well. Here we describe in multiple model systems, including iPSC-derived human pancreatic organoids from CF patients, that the activity of PMCA4 is impaired by the decreased expression of CFTR in ductal cells. The regulation of PMCA4, which colocalizes and physically interacts with CFTR on the apical membrane of the ductal cells, is dependent on the calmodulin binding ability of CFTR. Moreover, CFTR seems to be involved in the process of the apical recruitment of calmodulin, which enhances its role in calcium signaling and homeostasis. Sustained intracellular Ca2+ elevation in CFTR KO cells undermined the mitochondrial function and increased apoptosis. Based on these, the prevention of sustained intracellular Ca2+ overload may improve the exocrine pancreatic function and may have a potential therapeutic aspect in CF.

cell biology↗

bioRxiv2020

Chronic Pain Patients Exhibit Individually Unique Cortical Signatures of Pain

We investigated how the trajectory of pain patients ongoing and fluctuating pain is encoded in the brain. In repeated fMRI sessions, 20 chronic back pain patients and 20 chronic migraineurs were asked to continuously rate the intensity of their endogenous pain. Linear mixed effects models were used to disentangle cortical processes related to pain intensity and to pain intensity changes. We found that the intensity of pain in chronic back pain patients is encoded in the anterior insula, the frontal operculum, and the pons; the change of pain of chronic back pain and chronic migraine patients is mainly encoded in the anterior insula. At the individual level, we identified a more complex picture where each patient exhibited their own signature of endogenous pain encoding. The diversity of the individual cortical signatures of chronic pain encoding results adds to the understanding of chronic pain as a complex and multifaceted disease.

neuroscience↗

bioRxiv2020

Establishment gaps in species-poor grasslands: artificial biodiversity hotspots to support the colonization of target species

Sowing of grass seed mixtures is a feasible and cost-effective method for landscape-scale grassland restoration. However, sowing only grasses usually leads to species-poor and dense grass sward, where the establishment of target forbs is hampered both by microsite and propagule limitation. To overcome these limitations and increase the diversity of species-poor sown grasslands we developed a novel method by creating establishment gaps. We used tillage to open gaps of 1 m2, 4 m2 and 16 m2 size in the dense grass sward of six species-poor sown grasslands in the Great Hungarian Plain. We sowed high-diversity seed mixtures of 35 native species into all gaps. We analyzed vegetation development during the first five years after setting up the trial. We also studied the colonization dynamics of the sown species along four 20-m transects around each gap, resulting in a total of 1440 plots of 1 m2 size that were studied. Our results indicated that most of the sown species were able to establish permanently in the establishment gaps. The total cover and the cover of perennial sown species increased independently of gap size. Meanwhile the cover of short-lived sown species decreased during the five years. There was only a moderate level of weed abundance in the gaps, and weed cover decreased over the years. The sown target species started to colonize the species-poor grasslands surrounding the establishment gaps within five years. The highest number of species and individuals dispersed from the 4 m2-sized gaps, as they had a more stable development than small gaps and were exposed to lower grazing pressure than large ones. Implications for practiceO_LIEstablishment gaps are widely applicable tools to increase the diversity of species-poor grasslands. Gaps of 4 m2 represent a more feasible solution compared to larger openings also for the farmers, because there is only a moderate level of weed encroachment and smaller soil disturbance occurs during their creation. C_LIO_LIWe recommend sowing high-diversity seed mixtures containing both short-lived species that can establish in the first year and perennial species, which guarantee a high cover of target species later on. C_LIO_LIGaps sown with high-diversity seed mixture are highly resistant to unfavorable climatic conditions: increasing grass abundance in dry years does not hamper the recovery of target grassland species in the following years. C_LI

ecology↗

bioRxiv2020

Consumption rate and dietary choice of cattle in species-rich mesic grasslands

For the improvement and maintenance of the desirable ecological value of grasslands it is necessary to manage them in a way which maintains their structure and their long-term functioning. Extensive grazing plays a crucial role in the seasonal biomass removal, thereby it prevents litter accumulation and shrub encroachment. Defoliation and biomass removal are among the most important effects of grazing on the vegetation, while the sufficient quantity and quality of plant biomass is an important ecosystem service for animal husbandry. In order to maintain the long term functioning of pastures it is important to gather information about the amount of consumed biomass and the dietary choice of the grazers. Therefore, we studied the direct effects of grazing on species-rich meadow steppes in Central-Hungary and the underlying mechanisms of dietary choice of cattle using trait-based approach. We asked the following questions: (i) What are the direct effects of grazing on the main biomass fractions (litter, moss, forbs and graminoids)? (ii) Which traits distinguish the preferred and non-preferred vascular plant species? The studied pastures were divided into two adjacent units, which were managed differently in the study year: the grazed units were managed by grazing for three months before the sampling date, while the control units remained ungrazed until the sampling. We collected above-ground biomass samples, measured leaf traits and shoot nitrogen content of plants. The consumption of the litter and moss biomass was negligible, while the reduction of the live biomass of vascular plants was 65%. Grazing significantly decreased the flowering success of plants. Cattle consumed species characterized by high specific leaf area and high nitrogen content. Based on our results we emphasize that, in order to ensure the reproduction of most plant species in the long term, it is unfavourable to graze an area every year in the same period. Instead, it is recommended to use grazing in a mosaic spatial and temporal pattern. The livestock carrying capacity of an area and the long-term management of grasslands can be carefully planned based on biomass measurements and the nutritional value of plants, which is well indicated by some easily measurable plant properties such as specific leaf area and the nitrogen content of species.

ecology↗

bioRxiv2020

Vegetation and seed bank dynamics highlight the importance of post-restoration management in sown grasslands

Sowing grass seeds generally supports the rapid development of a closed perennial vegetation, which makes the method universally suitable for fast and effective landscape-scale restoration of grasslands. However, sustaining the recovered grasslands, and increasing their diversity is a challenging task. Understanding the role of seed bank compositional changes and vegetation dynamics contributes to designating management regimes that support the establishment of target species and suppress weeds. Our aim was to reveal the effect of post-restoration management on the vegetation and seed bank dynamics in grasslands restored in one of the largest European landscape-scale restoration projects. Eight years after restoration we sampled the vegetation and seed bank in a total of 96 plots located in 12 recovered grasslands in the Great Hungarian Plain. In each recovered grassland stand we designated a mown (mown from Year 1 to Year 8) and an abandoned sample site (mown from Year 1 to Year 3 then abandoned from Year 4 to Year 8). Mown and abandoned sites showed divergent vegetation and seed bank development. Abandonment led to the decline of sown grasses and higher cover of weeds, especially in the alkaline grasslands. Our study confirmed that seed bank has a limited contribution to the maintenance of biodiversity in both grassland types. We found that five years of abandonment had a larger effect on the seed bank than on the vegetation. We stress that long-term management is crucial for controlling the emergence of the weeds from their dense seed bank in restored grasslands. Implications for practiceO_LISeed sowing of grass mixtures can be a feasible tool for restoring grasslands at large scales. However, the developed vegetation usually has low biodiversity and a high seed density of weeds is typical in the soil seed bank even several years after the restoration. Therefore, post-restoration management is necessary for suppressing weeds both aboveground and belowground. C_LIO_LIWe recommend to design the long-term management of the sites subjected to grassland restoration already in the planning phase of the restoration projects and ensure that the management plan is ecologically and economically feasible. C_LIO_LIWe recommend to complement the monitoring of vegetation with the analysis of soil seed bank for evaluating restoration success. C_LI

ecology↗

bioRxiv2020

Underground deserts below fertility islands? - Woody species desiccate lower soil layers in sandy drylands

Woody plants in water-limited ecosystems affect their environment on multiple scales: locally, natural stands can create islands of fertility for herb layer communities compared to open habitats, but afforestation has been shown to negatively affect regional water balance and productivity. Despite these contrasting observations, no coherent multiscale framework has been developed for the environmental effects of woody plants in water-limited ecosystems. To link local and regional effects of woody species in a spatially explicit model, we simultaneously measured site conditions (microclimate, nutrient availability and topsoil moisture) and conditions of regional relevance (deeper soil moisture), in forests with different canopy types (long, intermediate and short annual lifetime) and adjacent grasslands in sandy drylands. All types of forests ameliorated site conditions compared to adjacent grasslands, although natural stands did so more effectively than managed ones. At the same time, all forests desiccated deeper soil layers during the vegetation period, and the longer the canopy lifetime, the more severe the desiccation in summer and more delayed the recharge after the active period of the canopy. We conclude that the site-scale environmental amelioration brought about by woody species is bound to co-occur with the desiccation of deeper soil layers, leading to deficient ground water recharge. This means that the cost of creating islands of fertility for sensitive herb layer organisms is an inevitable negative impact on regional water balance. The canopy type or management intensity of the forests affects the magnitude but not the direction of these effects. The outlined framework of the effects of woody species should be considered for the conservation, restoration, or profit-oriented use of forests as well as in forest-based carbon sequestration and soil erosion control projects in water-limited ecosystems.

ecology↗