Search Results (101)

Stevia rebaudiana Bertoni, a semi-perennial herb from the Asteraceae family, is native to the Paraguay–Brazil border region. The growing industrial interest in this species is due to its natural sweetening properties, such as steviol and its derivatives, which offer sweetness without adding calories. Morphological traits are crucial for assessing genetic variability and ensuring distinctness, homogeneity, and stability (DHS) for cultivar protection. This study characterized 19 elite Stevia genotypes from Embrapa Cerrados’ Active Germplasm Bank (BAG) using 21 morphological descriptors from Brazil’s Ministry of Agriculture, Livestock, and Supply (MAPA). Genetic distances were calculated using the simple coincidence index complement method, and clustering was performed via the Unweighted Pair-Group Method with Arithmetic Mean (UPGMA). The results showed that 17 of the 21 descriptors (>80%) effectively differentiated the genotypes, revealing significant genetic variability. Dendrogram analysis identified at least four major similarity groups, highlighting the potential of these genotypes for Stevia breeding programs. These findings underscore the suitability of these elite genotypes for developing superior varieties adapted to Cerrado conditions, supporting future cultivation and genetic improvement efforts. Full article

Climate change represents a major global challenge, with semi-arid regions like the province of Almería being particularly vulnerable. Almería’s dependence on climate-sensitive sectors such as agriculture and tourism, coupled with the absence of perennial rivers, increases its exposure to extreme events including heatwaves, droughts, and extreme precipitation events like storms. This study proposes a semi-quantitative methodology to assess climate risk across different sectors at the municipal level, combining indicators of hazard, exposure and vulnerability within the framework of the IPCC AR6. Exposure and vulnerability indicators were derived from regional, national and European datasets, while hazards were characterized using downscaled Essential Climate Variables. After data collection, the indicators were normalized using a percentile-based approach to ensure their comparison and replicability, especially in data-scarce contexts. The results reveal both sectoral and spatial patterns of risk under three different climate change scenarios, highlighting municipalities with a higher level of exposure, vulnerability and risk. Although the static nature of exposure and vulnerability indicators represents a limitation in future risk quantification, the findings remain valuable for identifying priority areas for targeted adaptation and mitigation strategies. The proposed semi-quantitative risk methodology based on indicators is of great interest and relevance for understanding differences at local scales, as well as for implementing adaptation and mitigation solutions adjusted to the real needs of each municipality. Full article

Solanum aculeatissimum is a herbaceous to semi-woody perennial plant native to the Brazilian ecosystem. It has naturalized extensively in southwestern China, posing significant threats to local biodiversity. This study systematically screened and integrated 100 distribution records from authoritative databases, including the Chinese Virtual Plant Specimen Database, the Global Biodiversity Information Facility, and Chinese Natural Museums. Additionally, 23 environmental variables were incorporated, comprising 19 bioclimatic factors from the World Climate Dataset, 3 topographic indicators, and the Human Footprint Index. The objectives of this research are as follows: (1) to simulate the plant’s current and future distribution (2050s/2070s) under CMIP6 scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5); (2) to quantify changes in the distribution range; and (3) to determine the migration trajectory using MaxEnt 3.4.4 software. The findings reveal that human pressure (contributing 79.7%) and isothermality (bioclimatic factor 3: 10.1%) are the primary driving forces shaping its distribution. The core suitable habitats are predominantly concentrated in the provinces of Yunnan, Guizhou, and Sichuan. By 2070, the distribution center shifts northeastward to Qujing City. Under the SSP5-8.5 scenario, the invasion front extends into southern Tibet, while retreat occurs in the lowlands of Honghe Prefecture. This study underscores the synergistic effects of socioeconomic development pathways and bioclimatic thresholds on invasive species’ biogeographical patterns, providing a robust predictive framework for adaptive management strategies. Full article

Desertification, accompanied by the loss of perennial grasses and bush encroachment, affects more than 10% of the world’s drylands, thereby placing increasing pressure on rangelands and farmers’ livelihoods. In Namibia, rangeland desertification is exacerbated by external shocks such as droughts, market changes, and new regulatory frameworks that have led to profound social and ecological changes within this tightly coupled social–ecological system (SES). In this context, the interrelationship among system components, drivers, and external factors, as well as the impact of strategies to halt desertification, remain poorly understood. The present study employed a retrospective mixed-methods approach to investigate the drivers of desertification on Namibia’s freehold farms by applying the social–ecological trap (SET) concept. Our approach combined remote sensing methods with semi-structured interviews and a literature review. The aim was to decipher the underlying processes and self-reinforcing feedback loops and to identify associated changes in the social and ecological subsystem. Our results revealed that inadequate grass availability, coupled with income deficits, serves as a pivotal catalyst for rangeland desertification, perpetuating a self-reinforcing feedback loop. To avoid or mitigate the effects of ecological regime shifts and to help farmers escape the SET of desertification, it will be necessary to implement changes in the dominant feedback loops through long-term risk mitigation strategies, such as rangeland restoration measures, as well as on- and off-farm income diversification. These strategies will provide a foundation for subsequent research on effective long-term mitigation strategies to prevent further rangeland desertification and to secure the livelihoods of farmers. Full article

Perennial ryegrass represents the most important forage grass, yet its generally low drought tolerance leads to reduced yields under water scarcity. Nevertheless, large intra- and inter-population variability could be a pool for selecting new drought-tolerant varieties. In this study we evaluated three populations (K-11, Exp population and Shandon) under semi-controlled conditions across four watering levels (100%, 70%, 50% and 30% of field water capacity), focusing on yield and key morphological and biochemical traits. Dry matter yield and root dry mass decreased in all populations under limited watering conditions. The highest biomass production in such conditions was observed in the Exp population, likely due to better root performance in the deeper soil layer. On the other hand, oxidative stress markers (MDA and H₂O₂) and water-soluble sugars, which indicated the best physiological status in cultivar K-11 under severe drought, did not lead to the highest DMY. These results show the importance of including multiple physiological and biochemical traits in breeding processes, with the aim of developing perennial ryegrass cultivars capable of withstanding prolonged and intense summer drought as a consequence of climate change. Full article

Guayule (Parthenium argentatum A. Gray) is a valuable domestic source for rubber and resin. At its center of origin in the Northern Mexico and Southern Texas deserts, guayule, a perennial shrub, is hybridized with its relative species mariola (Parthenium incanum Kunth). As rubber and resin are the main products derived from guayule, there is interest in using guayule bagasse as a bioenergy feedstock to meet the growing bioenergy and biofuel demands. This study aimed to explore and characterize phenotypic diversity in cell wall constituents (lignin, cellulose, and hemicellulose) and their yields among 51 guayule and mariola genotypes under two irrigation regimes (well-watered and water-stressed). Significant genotypic and environmental effects were observed for lignin, cellulose and hemicellulose concentrations, and yields, indicating the wide genetic variability of the collection for bioenergy-related traits. Moderate to high entry-mean heritability values for lignin, cellulose, and hemicellulose suggest that selection is feasible to enhance genetic gain. Significant positive correlations were found among cellulose and hemicellulose concentrations and yields, indicating the possibility to select multiple traits together during breeding cycles. High positive correlations between rubber and resin and lignin, cellulose, and hemicellulose yields highlight the opportunity to develop guayule germplasm with enhanced multi-use traits for industrial applications. Wide variations in drought stress indices (stress tolerance index, yield index, and yield stability index) underscore the environmental impact on the lignocellulosic traits. Several genotypes were identified with high stress index scores and could be parental candidates for improving guayule for arid and semi-arid sustainable agricultural systems. The current study is the first to characterize the phenotypic diversities in guayule and mariola for lignocellulosic components and yield, providing the foundation for future breeding efforts aimed at enhancing guayule’s value for diverse production goals and environmental conditions. Full article

This study looked at the impact of planting year differences on vegetation and soil parameters in Pinus sylvestris plantation forests in northern Mongolia. Tujiin nars region has three study sites: 18- to 20-year-old plantation forests planted in 2003, 2004, and 2005, as well as natural regeneration stand, natural forest, and steppe area. Three plots with distinct plantation stand types were constructed at each location to investigate changes in vegetation and soil attributes. Understory vegetation was comprised of 92 species of plants, including 4 shrubs, 1 semi-shrub, species, and 84 herb species (5 annuals and 87 perennials) belonging to 78 genera of 35 families. Species richness, total coverage, and biomass accumulation were significantly higher in the oldest plantation (2003). Soil pH ranged from 6.52 to 7.41, across plantations, with steppe and forest edge soils being alkaline and plantation soils slightly acidic. Soil temperature varied between 17.7 and 24.7 °C, where the lowest temperature was in the naturally regenerated stand and the highest was in the steppe plot. The average soil moisture varied from STP (5.1%) to MGS (12.0%) and decreased by 2.0% in the 2003 plantation forest. Available nitrogen, soil organic carbon, and carbon stock were higher in the top soil and decreased by depth of profile and differed in plantations by year of planting. Furthermore, the change in understory vegetation was significantly correlated with the soil moisture, fertility, and species composition was driven by over story density and crown parameters. Our findings revealed the importance of soil characteristics and understory vegetation in the effective restoration and management of Scots pine plantation in Mongolia and further management of planted Scots pine plantation in safeguarding resilient and productive forests in Mongolia. Full article

European semi-dry grasslands are habitats of high conservation value. Therefore, research into the mechanisms of community assembly is important for their effective management. Using data from 76 vegetation plots of calcareous and acidic semi-dry grasslands in continental Slovenia, the author analysed the composition of plant traits, focusing on less studied belowground traits. Community-weighted means were calculated for nine plant functional traits: life form, growth form, clonal growth organ (CGO) type, persistence of connection in CGO, number of clonal offspring shoots, lateral spreading distance, role of CGO, bud bank, CSR strategy. The results showed that both grassland communities were characterized by high local persistence (perennial plants with long-lived connections between ramets). Acidic grasslands had more species with rosettes, rhizomes and stress-tolerators, indicating more stressful conditions, probably due to low pH. Mesic grassland species with numerous stolons and longer lateral spread were also characteristic of acidic grasslands. Calcareous grasslands hosted more competitors, plants with leafy stems and plants with perennial main roots. This study contributes to a deeper understanding of grassland processes and provides a basis for future investigations of belowground plant traits and their function. Full article

Invasive species are a major driver of environmental change and pose a significPant threat to native biodiversity due to their ability to invade and establish themselves in natural or semi-natural ecosystems. This study analyzed the presence, abundance, and distribution of invasive alien plant species in a Mediterranean urban area, the municipality of Córdoba (Andalusia region, southern Spain). It includes an important historic city center, urbanized areas but also peri-urban natural and semi-natural sites around. A detailed review of bibliography and computerized botanical databases was conducted prior to an extensive fieldwork and GIS analysis carried out during 2021, 2022, and 2023. Our research identified 227 populations of 17 invasive plant species from 10 different families. These species represent 35% of the invasive plant species reported in the Andalusia region and 27% of those reported in Spain. In total, 53% of the species were introduced from America, especially South America, but no alien invasive species from other European regions were detected. The highest concentrations were found in ruderal areas, followed by abandoned fields, but also in urbanized areas, including the UNESCO World Heritage historic city center. Seven invasive herbaceous species were identified (perennial herbs), compared to 10 invasive tree species, with phanerophytes being the most abundant life form. This likely reflects the predominant use of alien woody species for ornamental and reforestation purposes, as well as the greater resilience of woody and perennial species to the increasingly warm and dry conditions of the Mediterranean climate—a phenomenon exacerbated in recent years by climate change. Our findings suggest that the use of non-native species as ornamentals is the primary driver of the establishment, spread, and ecological impact of invasive plants in the study area. This study provides valuable insights into the current situation and the potential future trajectory of invasive species, facilitating the development of management strategies and restoration efforts to address the growing issue of biological invasions in the Mediterranean region. Full article

Background: We explore how springs and their pastures are utilised by nomadic pastoralists and how they influence interchange and conflict between the custodians of the springs and the society of pastoralists in the broader region. Methods: The custodians of three spring locations in the Afar region of Ethiopia were interviewed to identify the advantages, and the challenges, of having springs on a pastoral estate. Results: The springs provide permanent water and health benefits, are used for cooking, and provide permanent pasture for livestock. In the Dobi Valley, the groundwater supporting the springs supports a population of the palm garayto (Hyphaene thebaica), which provides thatch and a liquor derived from the sap. The custodians of the springs are baaro-mara for their homelands and they welcome and provide access to the resources of the spring to Afar outsiders, gurro-mara. Recent invasions by the Somali Issa tribe have resulted in the deaths and displacement of Afar residents at Alalo-bad and Teo. The prickly shrub Prosopis juliflora has become another invasive threat with great impacts on the livelihood of the baaro-mara at two locations. Conclusions: Springs are oases where permanent water provides perennial resources in a semi-desert. However, the tenure of these precious havens can be subject to tribal contest and the resources of the springs have been recently undermined by invasion of a plant from another continent. The removal of the incipient population of Prosopis juliflora should be a priority before it proliferates further. Full article

Medicago sativa L. (Alfalfa) is a globally recognized forage legume that has recently gained attention for its high protein content, making it suitable for both human and animal consumption. However, due to its perennial nature and autotetraploid genetics, conventional plant breeding requires a longer timeframe compared to other crops. Therefore, genetic engineering offers a faster route for trait modification and improvement. Here, we describe a protocol for achieving efficient transient gene expression in alfalfa through genetic transformation with the Agrobacterium tumefaciens pCAMBIA1304 vector. This vector contains the reporter genes β-glucuronidase (GUS) and green fluorescent protein (GFP), along with a selectable hygromycin B phosphotransferase gene, all driven by the CaMV 35s promoter. Various transformation parameters—such as different explant types, leaf ages, leaf sizes, wounding types, bacterial concentrations (OD_600nm), tissue preculture periods, infection periods, co-cultivation periods, and different concentrations of acetosyringone, silver nitrate, and calcium chloride—were optimized using 3-week-old in vitro-grown plantlets. Results were attained from data based on the semi-quantitative observation of the percentage and number of GUS spots on different days of agro-infection in alfalfa explants. The highest percentage of GUS positivity (76.2%) was observed in 3-week-old, scalpel-wounded, segmented alfalfa leaf explants after 3 days of agro-infection at a bacterial concentration of 0.6, with 2 days of preculture, 30 min of co-cultivation, and the addition of 150 µM acetosyringone, 4 mM calcium chloride, and 75 µM silver nitrate. The transient expression of genes of interest was confirmed via histochemical GUS and GFP assays. The results based on transient reporter gene expression suggest that various factors influence T-DNA delivery in the Agrobacterium-mediated transformation of alfalfa. The improved protocol can be used in stable transformation techniques for alfalfa. Full article

Dominant species are crucial in regulating the structure and productivity of plant communities. Adaptation strategies to climate change vary among the dominant species of different life types. However, the responses of the ecological niches of dominant species to warming and precipitation in semi-arid grasslands and their impacts on community structure and function are unknown. This study involved conducting a long-term experimental simulation of warming and increased precipitation on grasslands in Inner Mongolia and studying population dynamics, ecological niches, and their responses to the structure and function of the community species of two dominant plants, L. chinensis (perennial rhizome grass) and S. krylovii (perennial clumped grass). The results show that the niche width of L. chinensis increased and S. krylovii decreased under warming and increased precipitation conditions. The overlap of L. chinensis and S. krylovii decreased under the same conditions. The niche widths of L. chinensis and S. krylovii were 1.22 for the control (C), 1.19 and 1.04 under warming (W) conditions, 1.27 and 0.97 under warming plus precipitation (WP) conditions, and 1.27 and 1.24 under the conditions of precipitation addition (P). The niche overlap of L. chinensis and S. krylovii were 0.72 in C, 0.69 in W, 0.68 in WP, and 0.82 in P. The biomass share and importance value of L. chinensis increased, and those of S. krylovii decreased in response to warming and precipitation. The effects of warming on species diversity and community stability are primarily influenced by the effects on the niche breadth of S. krylovii. Combined with our previous study, L. chinensis will offer more resources in communities in warmer and wetter steppe climates in the future. However, this is not conducive to community diversity. Full article

The classification of stream flow regimes has been a subject of study for over a half century in the fields of hydrology, geomorphology, ecology, and water resources management. But with the most recent Supreme Court decision on jurisdictional Waters of the United States (WOTUS) and the 2023 Conforming Rule, the answer to the question of which waters are relatively permanent has increased in importance and urgency. One state where this question is salient is Arizona, where approximately 95% of its streams are nonperennial. In this study, we use long-term (>30 years) daily discharge records from Arizona to assess semi-natural flow regimes of arid streams within the context of the 2023 Conforming Rule. Using flow percentile distributions, we distinguished flow permanency—ephemeral vs. intermittent vs. perennial—for 70 stream reaches distributed throughout the state. Ephemeral streams had a median flow of 0 cms and a 75th percentile flow permanence less than 25% (i.e., less than 3 months of flow for every 7.5 out of 10 years). On the other end of the spectrum, perennial streams had a 90th percentile flow permanence of 100%. In the middle, intermittent streams had a 75th percentile flow permanence greater than 25% and a 90th percentile flow permanence less than 100%. We also assessed the effect of the recent megadrought (since 1994) on flow permanency. As a result of the megadrought, four perennial streams transitioned to intermittent, four intermittent streams transitioned to ephemeral, and one perennial stream became ephemeral. The flow classification we present here is specific to Arizona streams but could be useful to other arid regions seeking to answer the question of which streams are relatively permanent in a typical year. Full article

Sugarcane plays a pivotal role in the Brazilian economy as a primary crop. This semi-perennial crop allows for multiple harvests throughout its life cycle. Given its longevity, farmers need to be mindful of avoiding gaps in sugarcane fields, as these interruptions in planting lines negatively impact overall crop productivity over the years. Recognizing and mapping planting failures becomes essential for replanting operations and productivity estimation. Due to the scale of sugarcane cultivation, manual identification and mapping prove impractical. Consequently, solutions utilizing drone imagery and computer vision have been developed to cover extensive areas, showing satisfactory effectiveness in identifying gaps. However, recognizing small gaps poses significant challenges, often rendering them unidentifiable. This study addresses this issue by identifying and mapping gaps of any size while allowing users to determine the gap size. Preliminary tests using YOLOv5 and ImageJ 1.53k demonstrated a high success rate, with a 96.1% accuracy in identifying gaps of 50 cm or larger. These results are favorable, especially when compared to previously published works. Full article

Maintaining biodiversity in agricultural landscapes is a major challenge for environmental protection in Europe. Vineyards rely heavily on agrotechnical interventions such as herbicide use and tillage for weed control, which affect biodiversity and can lead to soil erosion and resistant weed populations. The fragmentation of agricultural landscapes affects biodiversity by altering community composition and often reducing plant population sizes and genetic diversity. However, it can also increase the abundance of certain species and enhance population resilience to environmental change. Vineyards can support high levels of biodiversity and provide ecosystem services due to their semi-natural habitat structure. This research evaluates vegetation biodiversity using phytosociological relevés in different vineyards. Our results show that species richness and biodiversity are significantly influenced by vineyard age and management type. This study highlights differences in the representation of plant functional groups, with perennial taxa in grassy inter-row contributing to anti-erosion functions and serving as food sources for pollinators. The root zone around vine trunks shows an increase in invasive species with vineyard age, posing a risk to the agroecosystem. Vineyards predominantly follow a ruderal ecological strategy, using nutrients and light efficiently, while tolerating management disturbances. Understanding these dynamics is critical for developing sustainable vineyard management practices that support biodiversity and ecological resilience, counteract the homogenization of agricultural landscapes, and promote the coexistence of viticulture and species-rich ecosystems. Full article