Chunnan Fan

Vaccinium uliginosum (VU) is one of the most precious wild berry plants distributed in the Changbai Mountain region in northeast China. Eight key morphological traits of VU were analyzed to examine the variation among and within five natural populations at different altitudes, as well as their response to environmental factors. The study results showed an increasing trend of variation among populations with ascending altitudes, but the range variation within populations exhibited a decreasing trend. The diversity level among populations was found to be higher than that within populations, and the five populations of VU were classified into four groups. Except for leaf width and twig length, all other morphological traits demonstrated significant or extremely significant correlations. Generally, with increasing altitude, leaf length decreased, while plant height, clear bole height, and basal diameter decreased significantly, and similar trends were observed with moisture factors, while a significant positive correlation was found with temperature factors. Among them, the morphological traits of clear bole height and basal diameter exhibited the strongest correlation with environmental factor variations. Overall, these findings indicate extensive variation in the morphological traits of VU within and among populations at different altitudes, with clear responses to changes in environmental factors.

The promotion of forest resource protection and sustainable development relies greatly on the value of forest ecosystem services. In Jilin Songhuajiang Sanhu National Nature Reserve in Northeast China, a total of 169 sample plots were examined and analyzed to evaluate the provisioning and supporting services provided by the forest ecosystem. The study revealed that the near-mature and over-mature Fraxinus mandshurica forest have relatively high timber supply and species resources conservation values per unit area, respectively. Furthermore, the mature Betula platyphylla forest has the highest forest nutrient retention value, while the near-mature Juglans mandshurica forest has the highest soil conservation value, with the nitrogen fixation value accounting for the highest proportion. The forest ecosystem services in the reserve have a total value of 659.07 million $⋅y^–1. The main contributors to the value are the services of soil fertilizer conservation, timber supply, and species resources conservation, with the mixed broad-leaved forest and Quercus mongolica forest being the main contributors, accounting for 63.1 and 18.8% of the total value, respectively. Nonetheless, the service value of per unit area in J. mandshurica forest is the highest. Near-mature and mature forests are the main contributors to the total value, accounting for 42.3 and 34.9%, respectively. Forest lands exhibit significant variations in the values of provisioning and supporting services across different stand types and age groups.

Under the influence of human activities, surface water quality has been significantly affected, which threatens human health and sustainability. In order to clarify the potential risks of heavy metal pollution to human health in river water, two tributaries of the Tumen River with significant differences in human activity interference were selected for investigation. Comparative analysis of the contents of chromium (Cr), cuprum (Cu), arsenic (As), cadmium (Cd), mercury (Hg), and plumbum (Pb) in the surface water of the two tributaries showed that the concentrations of As and Hg in some sampling sites exceeded the pollution standard values, and the Buerhatong River had a higher pollution level. Further analysis of the health risks revealed that the hazard quotient values of Cr, Cu, As, Cd, Hg, and Pb were <1, but the cumulative risk value of the Buerhatong River was higher than 1 for children, indicating adverse effects on human health. The As levels under the fish ingestion scenario had unacceptable carcinogenic risks, while the Cr in the Buerhatong River for adults and Cr and Pb in the Buerhatong River and Hunchun River for children had acceptable carcinogenic risks. Moreover, the As in the incidental water ingestion scenario also had acceptable carcinogenic risks. Therefore, the increase in human activity intensity can promote the increase in the health exposure risk of heavy metals in river water, and fish ingestion was the main exposure pathway, while children had higher exposure risks than adults.