Seasonal and daily pattern, temporal and spatial variability of ecosystem CO2-exchange in a temperate Pannonian loess grassland

In the photosynthetically most active spring, summer and autumn vege­ tation period the investigated grassland did maintain a relatively strong daytime carbon gain. During winter the grassland displayed a slight daytime carbon loss. These data suggest that the grassland was a weak sink for carbon in the investigated period. CO2 exchange variability during the day seemed to be independent from that of the daily photosynthetic radiation. Thus other factors like soil respiration, soil moisture content and temperature and their interactions could be responsible for the high daily variabil­ ity of grassland CO2-exchange. The considerable temporal (daily and seasonal) vari­ ability of the grassland CO2-exchange can be considered as a characteristic feature of the grassland CO2-exchange. In the investigated loess grassland vegetation the variabil­ ity of CO2-exchange showed clear dependence on measuring area, which is obvious in the CV of NEE. We hypothetised that the spatial scale with the lowest variability is the characteristic area of the grassland ecosystem\u27s CO2-exchange (CO2-exchange physi­ ological unit). In general decreased variability indicates a more regulated state.In the photosynthetically most active spring, summer and autumn vege­ tation period the investigated grassland did maintain a relatively strong daytime carbon gain. During winter the grassland displayed a slight daytime carbon loss. These data suggest that the grassland was a weak sink for carbon in the investigated period. CO2 exchange variability during the day seemed to be independent from that of the daily photosynthetic radiation. Thus other factors like soil respiration, soil moisture content and temperature and their interactions could be responsible for the high daily variabil­ ity of grassland CO2-exchange. The considerable temporal (daily and seasonal) vari­ ability of the grassland CO2-exchange can be considered as a characteristic feature of the grassland CO2-exchange. In the investigated loess grassland vegetation the variabil­ ity of CO2-exchange showed clear dependence on measuring area, which is obvious in the CV of NEE. We hypothetised that the spatial scale with the lowest variability is the characteristic area of the grassland ecosystem\u27s CO2-exchange (CO2-exchange physi­ ological unit). In general decreased variability indicates a more regulated state

Determining the Anti-Erosion Efficiency of Forest Stands Installed on Degraded Land

Erosion caused by human activities is one of the reasons for forest soil degradation worldwide, with a direct impact on forest stands development, including reduced forest productivity. Therefore, in order to establish sustainable stand management practices, it is essential to assess soil losses in various forestry activities. Moreover, this phenomenon is studied little in stands, especially those established on degraded land. In Romanian geographical conditions, where sloping land is up to 67% of the territory and is influenced by natural factors as well as intense human activities, the soil and vegetation suffer serious ecological imbalances. In order to achieve the proposed objectives regarding the evaluation of stands in terms of anti-erosion effectiveness, we analyzed the consistency and the number of trees on the surface, the weight of the seedlings, and the surface runoff from the perspectives of rainfall and soil retention. In the two stands included in this study, the influence of rain intensity was 39% in compartment 49 and 38% in compartment 73, directly influencing surface runoff. The ground retention’s influence on surface runoff was 28% in both compartments. The indirect surface runoff was influenced by the consistency of the stands and by the degree of proximity of the crowns, which directly influenced the intensity of rain. In addition to analyzing these two parameters (rain intensity and ground retention), it was also observed that the degree of proximity to the crowns directly influenced the intensity of the rainfall within the forest, which, in turn, indirectly affected the runoff

Consuming Blackberry as a Traditional Nutraceutical Resource from an Area with High Anthropogenic Impact

The most serious quality issue of natural resources for human consumption or medicinal purposes is the contamination with pollutants harmful to consumers. Common blackberry (Rubus fruticosus L.) is a sought-after nutraceutical and an important component in herbal medicine in many places around the globe. The present study aims to analyze the level of heavy metal bioaccumulation in blackberry organs, as well as its spatial distribution in two consecutive years immediately after the interruption of the extended activity of the industrial source of pollution. The research was conducted in one of the most polluted areas in Romania and Eastern Europe, within a 26 km radius of the source of pollution. The Pb, Cd, Cu, and Zn concentrations in the leaves, flowers, and unwashed blackberry fruits were analyzed spectrophotometrically through flame atomic absorption spectroscopy (FAAS). The results show that blackberry is an important bioaccumulator of these heavy metals—71% of the Pb concentration values and 100% of the Cd concentration values exceeded the World Health Organization thresholds by up to 29 and 15 times, respectively. Also, the leaves are the largest reservoirs of Pb and Zn (the median values: 51.4 mg/kg dry weight and 105.2 mg/kg d.w., respectively), and the flowers contained the largest quantities of Cd and Cu (2.54 mg/kg d.w. and 11.3 mg/kg d.w., respectively). The Pb concentrations decreased by a power function in relation to the distance from the source of pollution. The implications of these results on the safety of the use of blackberry are discussed. The urgent necessity for food education of the local population which consumes contaminated nutraceutical products is emphasized

Black Locust (Robinia pseudoacacia L.) in Romanian Forestry

This paper presents a literature review of black locust (Robinia pseudoacacia L.) and the knowledge accumulated by Romanian foresters and researchers, covering species propagation, stand management, and vulnerability issues. As highlighted by numerous authors, black locust manifests dual features, both as an exogenous species and one that is already naturalized. The main drivers for this species’ expansion in Romania is its ecological adaptability on degraded lands, fast growth, and high biomass yields, in addition to other economic benefits. Black locust plantations and coppices also offer an important range of ecosystem services such as CO2 sequestration, landscape reclamation, fuel wood, or maintaining traditional crafts in regions with little to no forest cover. Highlighted disadvantages include short lifespan, invasiveness when introduced on fertile sites, and dieback in drought/frost prone areas. The results of extensive research and studies are captured in technical norms, although aspects such as species genetics, invasive potential, and adaptation to climate change dynamics call for more research and optimizing in species management. As Romania rallies its efforts with those of the international community in order to address climate change and desertification, black locust stands out as a proven solution for reclaiming degraded lands when native species are not an alternative

Data from: Worldwide evidence of a unimodal relationship between productivity and plant species richness

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity