Vegetative Functions Research Articles

Resource redistribution mediated by hydrological connectivity modulates vegetation response to aridification in drylands

Water scarcity poses a significant life constraint in global drylands that determines species adaptations and mosaic of exposed bare areas and vegetation patches. Runoff‐water redistribution resulting from this spatial configuration has been suggested as a key process controlling water availability for vegetation and ecosystem functioning. However, the potential of this process to ameliorate the negative impacts of aridification in drylands remains unclear, and there is no empirical evidence of its relevance on natural ecosystems under different levels of aridity and disturbance regimes. To address this gap, we analysed temporal series of the normalized vegetation index (NDVI, a proxy of vegetation functioning) along a regional aridity–disturbance gradient under current and future climatic conditions. We found that mean NDVI increases in areas of runoff water accumulation (calculated using a water redistribution index) until a certain threshold, above which vegetation patches are not able to retain extra runoff water. Once thresholds were identified, we analysed the role of water redistribution on vegetation dynamics by analysing temporal series of monthly NDVI in a space–for–time substitution approach. The obtained results provided further evidence of the runoff water redistribution on vegetation, triggering a positive feedback between water accumulation and vegetation growth. Results obtained by the combination of the obtained model with climatic data from the 6th IPCC report suggest that this feedback could ameliorate the expected negative effects of aridification in drylands. However, this effect is partially counterbalanced in scenarios of high human disturbance and in areas where vegetation is not able to trap and retain the extra amount of resources given by runoff. Overall, our results provide empirical evidence of the relevance of runoff redistribution as a key process linking vegetation patterns to climate resistance in drylands that underscores its importance in the analysis and modelling of drylands' responses to aridification.

Shifts in the ecological drivers influence the response of tree and soil carbon dynamics in central Himalayan forests.

Understanding and regulating global carbon relies crucially on comprehending the components and services of forest ecosystems. In particular, interactions that govern carbon storage in trees, soil, and microbes, driven by factors like vegetation structure, function, and soil characteristics, remain poorly understood, especially in the central Himalayas. To address this gap, we investigated carbon storage in tree aboveground biomass, root biomass, and soil across different vegetation types. We also examined how vegetation parameters {vegetation diversity (H'), diameter at breast height (DBH), basal area (BA), and biomass}, and soil characteristics {bulk density (BD), moisture (Mo), pH, and total nitrogen (N)} might influence forest carbon storage. Our study, based on 14 plots (0.1ha each) spanning four distinct vegetation types {Sal forest (SF, 3), Chir-pine forest (PF, 4), Nepalese-alder forest (AF, 3), and Banj-oak forest (OF, 4)} in the central Himalaya, revealed several key insights. Tree carbon storage ranged from ∼79 to 261MgC ha-1, accounting for 41-65% of forest carbon storage, while soil carbon storage ranged from ∼28 to 69MgC ha-1, contributing 35-58%. These values varied with vegetation types and were influenced by the vegetation and soil characteristics associated with each forest type. Important contributors to tree and soil carbon storage included soil Mo, N, and vegetation structural diversity (H', BA), explaining 8-64 % of the variation. Path analysis indicated that increased vegetation diversity, soil properties, and conservative traits (fine roots and leaves) strongly influence tree and soil carbon storage. The study highlights the potential complex system to optimizing carbon storage in natural forest ecosystems, offering valuable insight for managing carbon sinks. Further research is needed to fully understand ecosystem responses to carbon storage across different forest habitats and different spatial-temporal scales.

Simple ecological indicators benchmark regeneration success of Amazonian forests

Natural regeneration of Amazon forests offers a promising strategy to mitigate forest loss and advance the goals of the UN Decade on Ecosystem Restoration. However, the vast variability in regeneration rates across environmental gradients and over time poses considerable challenges for assessing regeneration success and ecosystem services provision in human-modified landscapes. Here we compiled 448 plots from forest regeneration in the Amazon to investigate the drivers of regrowth capacity and identify robust ecological indicators. By modeling optimal successional trajectories, we estimated reference values for vegetation structure, diversity, and functioning. After 20 years, successful regeneration should reach a minimum basal area of 14 m². ha−¹, at least 34 tree species per 100 individuals, a structural heterogeneity index of 0.27, and 123 Mg.ha−¹ of aboveground biomass. These straightforward indicators and reference values provide a foundational framework for governments and practitioners to assess success and establish targets for Amazon restoration efforts.

Soil Microbial Communities Changes Along Depth and Contrasting Facing Slopes at the Parque Nacional La Campana, Chile

The Parque Nacional La Campana (PNLC) was recently recognized for its high soil surface microbial richness. Here, we explored the microbial community structure in soil profiles from contrasting facing slopes where sclerophyllous forest (SF) and xerophytic shrubland (XS) develop. Soil physicochemical conditions (dry density, pH, and organic matter C and N isotopic soil signatures) were determined at three depths (5, 10, and 15 cm depths). Amplicon sequencing (16S rRNA and ITS1-5F) and specific quantification (qPCR bacteria, archaea and ammonia-oxidizing archaea, fungi) were used to profile the microbial community. Our results indicate that opposite slopes, with different vegetation types and soil conditions studied potentially explained the spatial variability of the microbial community composition, especially between sites than through soil depth. Discriminative taxa were observed to vary between sites, such as, C. nitrososphaera (ammonia-oxidizing archaea) and Sphingomonas, and bacteria associated with Actinobacteria and Bacteroidetes were predominant in SF and XS, respectively. Fungi affiliated with Humicola and Preussia were more abundant in SF, while Cladosporium and Alternaria were in XS. Higher ASV richness was observed in SF compared to XS, for both prokaryotes and fungi. Furthermore, SF showed a higher number of shared ASVs, while XS showed a decrease in unique ASVs in deeper soil layers. In XS, the genus DA101 (Verrucomicrobia) increases with soil depth, reaching higher levels in SF, while Kaistobacter shows the opposite trend. PNLC soils were a reservoir of redundant microbial functions related to biogeochemical cycles, including symbiotic and phytopathogenic fungi. In conclusion, as with the predominant vegetation, the structure and potential function of microbial life in soil profiles were associated with the contrasting the effect of facing slopes as toposequence effects.

Adrenochrome formation during photochemical decomposition of "caged" epinephrine derivatives.

Control of biological activity with light is a fascinating idea. "Caged" compounds, molecules modified with photolabile protecting group, are one of the instruments for this purpose. Adrenergic receptors are essential regulators of neuronal, endocrine, cardiovascular, vegetative, and metabolic functions. These receptors are largely used as pharmacologic targets. Photolabile "caged" analogs of adrenergic receptor agonists has been reported more than 30years ago. We report that the photolysis of epinephrine analogs, apart from liberation of the epinephrine, is accompanied by a formation of significant amount of adrenochrome, a compound with neuro- and cardiotoxic effect.

Green roof runoff reduction of 84 rain events: Comparing Sedum, life strategy-based vegetation, unvegetated and conventional roofs

Green roofs have emerged as effective stormwater management systems, but understanding the contribution of their various components to hydrological performance is crucial for optimizing their design and implementation. More empirically measured data on the hydrological function of green roof vegetation is needed, especially under realistic low-maintenance, non-irrigated scenarios. Further, targeted, evidence-based plant selection based on ecological theories may improve green roof hydrological performance. Previous research has suggested that, in contrast to monocultures, mixtures of species with complementary traits could optimize provisioning of various ecosystem services. Thus, species mixtures based on their adaptive life strategy using the CSR theory (Competitor, Stress tolerator, and Ruderal) were hypothesized to have better hydrological performance than a Sedum monoculture or bare substrate under natural conditions over multiple seasons. To test this hypothesis, the runoff from thirty 2 m2 green roof modules was measured. The retention and detention performance of different green roof treatments were evaluated for 84 precipitation events of varying rain depth and intensity during snow-free periods. Differences in retention as well as detention between the vegetation treatments varied, but generally increased with increasing rain event volume and the Stress-tolerant treatment generally performed better than bare substrate. On a mean event basis, the mixture of stress-tolerator species demonstrated a 74 % retention rate, while the Bare substrate retained 72 % of the rainfalls. Overall, the green roofs, including bare substrate and vegetated treatments, effectively retained >50 % of the cumulative precipitation depth. In line with previous studies, the Sedum monoculture generally showed worse hydrological performance than other non-succulent vegetation mixtures, despite its relatively high cover and survival. The vegetated treatment with the highest species richness and diversity in life strategies (Mix) did not provide the best vegetation cover, or hydrological performance. Instead, the Stress-tolerant treatment, characterized by the high survival rate of a single graminoid species, consistently demonstrated superior event-based stormwater retention and peak attenuation capabilities.

Pemilihan Vegetasi terhadap Kriteria Ruang Terbuka Stadion di Jakarta International Stadium

<em>The stadium open space at JIS has the concept of sustainable landscape by considering ecological, aesthetic, and social aspects. This study’s goal is to identify several vegetative traits that meet the standard deviation of the area being studied. This study's methodology consists of qualitative analysis based on related literature research of the type, function, and layout of vegetation with case studies of stadium open spaces. The results show that the selection of ecologically functioning vegetation dominates in JIS. Vegetation for social functions close to seating and architectural functions lies in harmony with the shape of the composition of the building mass with the shape of the tree canopy that embodies building performance. The use of grass is ecologically intended for water catchment because JIS has a zero run off concept. Vegetation selection and replanting of relocation trees with adaptive planning to the location and conditions of JIS and low maintenance as well as to meet the green-based area in the green building concept</em>

Ichnotaxonomy of microboring traces in marine aphotic depths

Microboring traces in carbonate skeletal fragments deposited in aphotic depths of the oceans are studied, evaluated, and described with respect to their marine ecology and palaeoecology as well as ichnotaxonomy. Sand-size deep sea sediment particles dredged from depths ranging between 600 and 3266 m of the Bermuda Pedestal, Central Atlantic Ocean, the Florida Escarpment, the Mediterranean Sea, the Red Sea and the Indian Ocean were studied. Following ichnological rules, trace fossils are described as ichnogenera and ichnospecies, defined as products of organismal behaviour. This, in our view, refers to the growth habit of microboring organisms in response to environmental stimuli within the substrate they penetrate. The problem of palaeobathymetry is discussed in conjunction with the distinction between light-dependent and light independent microboring organisms, with the emphasis on the latter. We considered this distinction to be important because only the light-dependent microborers have been recognized as indicators of ancient depositional depths, whereas the light-independent ones are expected to occur at any depth, subject to the availability of organic nutrients. Microboring organisms often leave morphologically similar traces due to convergent evolution. Their responses may change during their life cycle; they may produce different traces when pursuing their vegetative vs. reproductive functions. New ichnotaxa are described. All are regarded as organotrophs given their aphotic zone deep sea origin. This work presents the most complete set of deep sea microbial euendolith traces, to date.

Impact of vegetation coverage and configuration on urban temperatures: a comparative study of 31 provincial capital cities in China

Urban vegetation plays a crucial role in regulating temperatures and heat waves in urban areas. However, the influence of vegetation coverage and its configuration on surface temperatures in different climate zones at a national scale is unclear. To address this, we utilized high-resolution data to detect spatial patterns for 31 provincial capital cities in China. We integrated day and night surface temperatures to determine the influence of vegetative coverage and configuration on urban temperatures across different climate zones and city sizes. Our study revealed that a subtropical monsoon climate and medium-sized cities had the highest vegetative coverage and shape complexity. The best connectivity and agglomeration of vegetation were found in a temperate monsoon climate and large cities. In contrast, small cities, especially those under a temperate continental climate, had low vegetation coverage, high fragmentation, and weak agglomeration and connectivity. In addition, vegetative coverage had a negative impact on daytime surface temperatures, especially in large cities in a subtropical monsoon climate. However, an increase in vegetation coverage could result in warming at night in small cities in temperate continental climates. Although urban vegetation configuration also contributed to moderating surface temperatures, especially at night, they did not surpass the influence of vegetation coverage. The effect on nighttime temperatures of the configuration of vegetation increased by 3–6% relative to that of daytime temperatures, especially in large cities in a temperate monsoon climate. The contribution vegetation coverage and configuration interaction to cooling efficiency decreased at night, especially in medium-sized cities in a temperate continental climate by 3–5%. In addition, this study identified several moderating effects of natural and social factors on the relationship between urban vegetation coverage and surface temperatures. High duration of sunshine, low humidity and high wind speed significantly enhanced the negative impact of vegetation coverage on surface temperatures. In addition, the moderating effect of vegetation coverage was more pronounced in low population density cities and high gross domestic product. This study enhances understanding of the ecological functions of urban vegetation and provides a valuable scientific basis and strategic recommendations for optimizing urban vegetation and improving urban environmental quality.

Warming and disturbances affect Arctic-boreal vegetation resilience across northwestern North America.

Rapid warming and increasing disturbances in high-latitude regions have caused extensive vegetation shifts and uncertainty in future carbon budgets. Better predictions of vegetation dynamics and functions require characterizing resilience, which indicates the capability of an ecosystem to recover from perturbations. Here, using temporal autocorrelation of remotely sensed greenness, we quantify time-varying vegetation resilience during 2000-2019 across northwestern North American Arctic-boreal ecosystems. We find that vegetation resilience significantly decreased in southern boreal forests, including forests showing greening trends, while it increased in most of the Arctic tundra. Warm and dry areas with high elevation and dense vegetation cover were among the hotspots of reduced resilience. Resilience further declined both before and after forest losses and fires, especially in southern boreal forests. These findings indicate that warming and disturbance have been altering vegetation resilience, potentially undermining the expected long-term increase of high-latitude carbon uptake under future climate.

UAV Quantitative Remote Sensing of Riparian Zone Vegetation for River and Lake Health Assessment: A Review

River and lake health assessment (RLHA) is an important approach to alleviating the conflict between protecting river and lake ecosystems and fostering socioeconomic development, aiming for comprehensive protection, governance, and management. Vegetation, a key component of the riparian zone, supports and maintains river and lake health (RLH) by providing a range of ecological functions. While research on riparian zone vegetation is ongoing, these studies have not yet been synthesized from the perspective of integrating RLHA with the ecological functions of riparian zone vegetation. In this paper, based on the bibliometric method, the relevant literature studies on the topics of RLHA and unmanned aerial vehicle (UAV) remote sensing of vegetation were screened and counted, and the keywords were highlighted, respectively. Based on the connotation of RLH, this paper categorizes the indicators of RLHA into five aspects: water space: the critical area from the river and lake water body to the land in the riparian zone; water resources: the amount of water in the river and lake; water environment: the quality of water in the river and lake; water ecology:aquatic organisms in the river and lake; and water services:the function of ecosystem services in the river and lake. Based on these five aspects, this paper analyzes the key role of riparian zone vegetation in RLHA. In this paper, the key roles of riparian zone vegetation in RLHA are summarized as follows: stabilizing riverbanks, purifying water quality, regulating water temperature, providing food, replenishing groundwater, providing biological habitats, and beautifying human habitats. This paper analyzes the application of riparian zone vegetation ecological functions in RLH, summarizing the correlation between RLHA indicators and these ecological functions. Moreover, this paper analyzes the advantages of UAV remote sensing technology in the quantitative monitoring of riparian zone vegetation. This analysis is based on the high spatial and temporal resolution characteristics of UAV remote sensing technology and focuses on monitoring the ecological functions of riparian zone vegetation. On this basis, this paper summarizes the content and indicators of UAV quantitative remote sensing monitoring of riparian zone vegetation for RLHA. It covers several aspects: delineation of riparian zone extent, identification of vegetation types and distribution, the influence of vegetation on changes in the river floodplain, vegetation cover, plant diversity, and the impact of vegetation distribution on biological habitat. This paper summarizes the monitoring objects involved in monitoring riparian zones, riparian zone vegetation, river floodplains, and biological habitats, and summarizes the monitoring indicators for each category. Finally, this paper analyzes the challenges of UAV quantitative remote sensing for riparian zone vegetation at the current stage, including the limitations of UAV platforms and sensors, and the complexity of UAV remote sensing data information. This paper envisages the future application prospects of UAV quantitative remote sensing for riparian zone vegetation, including the development of hardware and software such as UAV platforms, sensors, and data technologies, as well as the development of integrated air-to-ground monitoring systems and the construction of UAV quantitative remote sensing platforms tailored to actual management applications.

Spatial-Temporal Analysis of the Effects of Frost and Temperature on Vegetation in the Third Pole Based on Remote Sensing

Frost events during the growing season can significantly impact vegetation function and structure. Solar-induced chlorophyll fluorescence (SIF) and the normalized difference vegetation index (NDVI) are two widely used proxies for measuring vegetation growth. However, the extent to which NDVI and SIF respond to frost events and how the responses vary under different temperature, precipitation, and shortwave radiation conditions are still unclear. In this study, spatially gridded meteorological data were employed to identify frost events during the growing season in the Third Pole. Subsequently, vegetation responses to the frost events were examined using remotely sensed SIF and NDVI data in different seasons in the Third Pole. During the growing season, the number of frost events declined faster from 2001 to 2009 than from 2010 to 2018. From 2001 to 2009, most alpine vegetation areas in the Third Pole exhibited greening trends. SIF exhibited a strong correlation with environmental factors and showed higher sensitivity to environmental factors compared to the NDVI. Over the past two decades, the impact of temperature and frost days on alpine vegetation has decreased while the impact of precipitation and radiation has increased. This suggests that the control mechanisms governing alpine vegetation are gradually shifting in response to ongoing climate change in the Third Pole. This study enhances our comprehension of frost changes in alpine regions during the growing season and enriches our understanding of how alpine vegetation responds to climate change.

Response of alpine vegetation function to climate change in the Tibetan Plateau: A perspective from solar-induced chlorophyll fluorescence

Vegetation change in the Tibetan Plateau (TP) is a crucial indicator of climate change in alpine regions. Previous studies have reported an overall greening trend in the vegetation structure across the TP, especially in its northeastern part, in response to a warming climate. However, variations in the vegetation function and the possible drivers remain poorly understood. Considering the optimal temperature for plants in TP is usually higher than the current temperature, our hypothesis is the function and structure of alpine vegetation have changed synchronously over past few decades. To test this hypothesis, we analyzed satellite-observed solar-induced chlorophyll fluorescence (SIF) and leaf area index (LAI) in the Yellow River source (YRS) region in the northeastern TP to quantify the long-term trends in vegetation functional and structural states, respectively. The results suggest that from 1982 to 2018, SIF increased significantly in 77.71 % of the YRS area, resulting in a significant upward trend of 0.52 × 10−3 mW m−2 nm−1 sr−1 yr−1 (p < 0.001) for the regional-mean SIF. This represents a 16.1 % increase in SIF, which is close in magnitude to the increase in LAI over the same period. The synchronous changes between vegetation function and structure suggest that improved greenness corresponds to a similar level of change in carbon uptake across YRS. Additionally, we used a multiple regression approach to quantify the contribution of climatic factors to SIF changes in YRS. Our analyses show that the increases in SIF were primarily driven by rising temperatures. Spatially, temperature dominated SIF changes in most parts of YRS, except for certain dry parts in the northern and western YRS, where precipitation had a greater impact. Our results are crucial for a comprehensive understanding of climate regulations on vegetation structure and function in high-elevation regions.

Assessing the ecological response plant and soil to the seawalls in the Laizhou bay coastal wetland, China

Coastal wetlands are extremely vulnerable to both marine damage and human activities. In order to protect these wetlands, many artificial seawalls have been constructed. However, studies are required to understand how coastal wetlands will evolve under the influence of artificial seawalls. Therefore, to understand this succession process of plants and their adaptation to habitats divided by seawalls, two different habitats inside and outside the seawalls were selected in Laizhou Bay, China. The results showed that there were 5 plant species outside the seawalls that were lower than the 13 species inside. Additionally, the dominant plant species were varied between the two habitats, with mostly annual herbs observed outside the seawalls and perennial shrubs inside. Soil salinity was higher outside the seawalls, which was the key impact factor of soil nutrient differences. The distribution of annual and perennial species may be constrained by spatial differences in soil stoichiometry. Therefore, the plants in coastal wetlands vary significantly at a small scale in response to the disturbance of artificial seawalls. The differences in soil and plants between the two habitats divided by the artificial seawalls provide a new insight for evaluating the artificial coastal projects. The only way to reduce the effects of seawalls on natural coastal wetland vegetation and ecosystem functions is to restore connectivity of tidal flow inside and outside the seawalls.

Green Lane Planning for Safety, Beauty, and Reduction of the Diffusion of Air Pollutants to the Environment in the Boyolali Interchange on Semarang-Solo Toll Road

Abstract The high mobility of people requires fast transportation making toll roads as an alternative route to break up congestion and shorten the distance to a place. The availability of toll roads that are passed by many motorized vehicles, causes air pollution. To reduce the impact of air pollution, greenery is needed that can absorb exhaust emissions. In this study, motor vehicle exhaust emissions focus on NO2 gas. The purpose of this study was to analyze the emission of NO2 gas pollutants from motor vehicles, the absorption capacity of NO2 by vegetation, and to plan green lane that can improve the quality of the interchange landscape. The research was conducted at the Boyolali Interchange. The research method used is descriptive-quantitative based on the potential and constraints on the site, as well as analysis of emissions and vegetation that can absorb NO2 gas pollutants. Based on the results of the analysis, the development of green lane space is divided based on the function of vegetation which includes clear zone, cushion planting, aesthetics, identity, conservation, and guides which it supported with trees, and shrubs. The area of land that has the potential to be developed into green lane is 41,956.3 m2. The volume of vehicles is 66,637 per day with the resulting NO2 gas emission of 57.797 g. After planning, the emission that can be absorbed by plants is 48,293.50 g. Planned green lane of the Boyolali Interchange can reduce 83,56% of NO2 gas emissions released by motorized vehicles.

The Thursina Creative Islamic Boarding School Landscape Design with an Ecological Approach

Abstract The Thursina Sukamakmur Creative Islamic Boarding School is a boarding school under the State Electricity Company Baitul Mal Foundation (YBM-PLN) ’s management in Sukamakmur Village, Bogor Regency. Education at this Islamic boarding school has the theme of agriculture, where students learn about rice farming and goat and chicken farming. This Islamic boarding school has an area of 16,610 m2 with sloping to steep terrain (more than 25%) and consists of Islamic boarding school buildings, livestock areas, and rain-fed rice fields. The pesantren is surrounded by rain-fed rice fields and is located on a hillside, so it has problems in hydrology when it rains, and strong winds blow from the hill towards the valley. Therefore, a master plan was prepared using an ecological approach, in which the solutions offered minimize artificial landscape elements and optimize the function of vegetation as a wind barrier. The wind barrier is made of pine trees with three layers of thickness. With this ecological approach, it is hoped that the management of the building and environment of the Thursina Creative Islamic Boarding School can be sustainable.

Some like it hot: Seed thermal threshold variation in obligate seeding Acacia pulchella along a climate gradient

Dormancy in seeds is a key persistence mechanism for many flowering plants. Physically dormant (PY) seeds have water impermeable seed coats, and in fire-prone systems a common mechanism for dormancy release is fire-induced soil heating. However, the thermal thresholds innate to seeds with PY may be influenced by vegetation, climate, and fire regimes, varying substantially between populations of the same species. To investigate intraspecific variation of thermal thresholds in PY seeds, we sampled obligate seeding Acacia pulchella (Fabaceae) which produces PY seeds. Sampling was undertaken from 13 populations across a climate gradient of rainfall and temperature, and between two vegetation communities in fire-prone Mediterranean-type ecosystems of south-west Western Australia. To test a range of weather and fire-induced soil heating dormancy-break scenarios, we conducted dry heat shock experiments between 40 and 140 °C for 10 min and scored germination for 16 weeks. We created population-specific thermal performance curves and extracted the dormancy release temperature at which 50 % of the seeds had germinated (DRT50), the optimum dormancy-breaking temperature to stimulate maximum germination (T0), and the lethal temperature at which 50 % of the seeds were killed (LT50). Generalised linear models were used to examine relationships between thermal thresholds and possible vegetation, climate, and fire regime drivers of intraspecific variation in seed traits. We found that thermal thresholds differed between vegetation communities, with thresholds consistently higher in forest-type ecosystems compared to open woodland, and the influence of climate varied significantly between the two communities. Seeds from Jarrah Forest populations had a DRT50 16.0 °C higher, a T0 9.7 °C higher, and LT50 7.8 °C higher than seeds from Banksia woodlands. A high rate of non-dormancy was identified in one population that had lost fire in its system and displayed significant germination after both summer and fire-related temperatures. The PY thermal thresholds modelled here provide insight into the strong influence of variable soil heating as a function of vegetation and fuel dynamics in fire-prone environments. Our findings highlight the significant intraspecific variation for this species and suggest that fire-induced soil heating generated by vegetation characteristics may be an overlooked element of fire regimes shaping seed traits.

Drivers of Daily Water Level Fluctuation of Shallow Groundwater in the Inner Delta of the River Danube

Groundwater flow systems are influenced by the changes in surface waters as well as climatic factors. These teleconnections significantly increase in cases of extreme weather conditions. To prepare and mitigate the effect of such phenomena, the background factors that create and influence natural processes must be recognized. In the present study, 94 shallow groundwater (SGW) wells’ water level time series were analyzed in the inner delta of the River Danube (Europe) the Szigetköz region to explore which factors contribute to the development of diurnal periodicity of SGW and what its drivers are. The relationship between surface meteorological processes and SGW dynamics in the Szigetköz region was investigated using hourly data from monitoring wells. Hourly water temperature data exhibited weak correlations with meteorological parameters. However, daily averaged data revealed stronger correlations, particularly between SGW levels and air temperature and potential evapotranspiration. Diurnal periodicity in SGW fluctuations correlated strongly with potential evapotranspiration. The study also demonstrated the role of capillary fringe dynamics in linking surface evapotranspiration with SGW fluctuations. Changes in groundwater levels, even small, can significantly affect soil moisture, vegetation, and ecosystem functioning, highlighting the sensitivity of the unsaturated zone to SGW fluctuations driven by surface processes.

Vegetation growth responses to climate change: A cross-scale analysis of biological memory and time lags using tree ring and satellite data.

Vegetation growth is affected by past growth rates and climate variability. However, the impacts of vegetation growth carryover (VGC; biotic) and lagged climatic effects (LCE; abiotic) on tree stem radial growth may be decoupled from photosynthetic capacity, as higher photosynthesis does not always translate into greater growth. To assess the interaction of tree-species level VGC and LCE with ecosystem-scale photosynthetic processes, we utilized tree-ring width (TRW) data for three tree species: Castanopsis eyrei (CE), Castanea henryi (CH, Chinese chinquapin), and Liquidambar formosana (LF, Chinese sweet gum), along with satellite-based data on canopy greenness (EVI, enhanced vegetation index), leaf area index (LAI), and gross primary productivity (GPP). We used vector autoregressive models, impulse response functions, and forecast error variance decomposition to analyze the duration, intensity, and drivers of VGC and of LCE response to precipitation, temperature, and sunshine duration. The results showed that at the tree-species level, VGC in TRW was strongest in the first year, with an average 77% reduction in response intensity by the fourth year. VGC and LCE exhibited species-specific patterns; compared to CE and CH (diffuse-porous species), LF (ring-porous species) exhibited stronger VGC but weaker LCE. For photosynthetic capacity at the ecosystem scale (EVI, LAI, and GPP), VGC and LCE occurred within 96 days. Our study demonstrates that VGC effects play a dominant role in vegetation function and productivity, and that vegetation responses to previous growth states are decoupled from climatic variability. Additionally, we discovered the possibility for tree-ring growth to be decoupled from canopy condition. Investigating VGC and LCE of multiple indicators of vegetation growth at multiple scales has the potential to improve the accuracy of terrestrial global change models.

Extreme functional specialization of fertile leaves in a widespread fern species and its implications on the evolution of reproductive dimorphism.

Resource allocation theory posits that organisms distribute limited resources across functions to maximize their overall fitness. In plants, the allocation of resources among maintenance, reproduction, and growth influences short-term economics and long-term evolutionary processes, especially during resource scarcity. The evolution of specialized structures to divide labor between reproduction and growth can create a feedback loop where selection can act on individual organs, further increasing specializaton and resource allocation. Ferns exhibit diverse reproductive strategies, including dimorphism, where leaves can either be sterile (only for photosynthesis) or fertile (for spore dispersal). This dimorphism is similar to processes in seed plants (e.g., the production of fertile flowers and sterile leaves), and presents an opportunity to investigate divergent resource allocation between reproductive and vegetative functions in specialized organs. Here, we conducted anatomical and hydraulic analyses on Onoclea sensibilis L., a widespread dimorphic fern species, to reveal significant structural and hydraulic divergences between fertile and sterile leaves. Fertile fronds invest less in hydraulic architecture, with nearly 1.5 times fewer water-conducting cells and a nearly 0.5 times less drought-resistant xylem compared to sterile fronds. This comes at the increased relative investment in structural support, which may help facilitate spore dispersal. These findings suggest that specialization in ferns-in the form of reproductive dimorphism-can enable independent selection pressures on each leaf type, potentially optimizing spore dispersal in fertile fronds and photosynthetic efficiency in sterile fronds. Overall, our study sheds light on the evolutionary implications of functional specialization and highlights the importance of reproductive strategies in shaping plant fitness and evolution.