Nitrogen (N) and phosphorus (P) are key elements essential for plant growth and development. Due to fertilizer application, rapid urbanization, and fossil fuel combustion, nitrogen deposition has reached relatively high levels in China. However, there is still uncertainty regarding the response of N:P stoichiometry in plants and soil to N deposition across different ecosystems. Therefore, a meta-analysis was conducted using 845 observations from 75 studies to evaluate the response of plant and soil N and P concentrations and N to P ratios across various ecosystems to N addition. The analysis revealed that N concentration and N:P stoichiometry in plants and soil increased under N addition, while P concentration in plants and soil decreased on average. Furthermore, the magnitude of these responses was related to the N input rate and experimental duration. Finally, the effects of N addition on N concentration, P concentration, and N:P in terrestrial ecosystems would alter their allocation patterns, depending on relevant climate factors such as mean annual temperature and mean annual precipitation. This study highlights the ecological impact of N addition on the biogeochemical cycling of major elements (N and P) in terrestrial ecosystems in China. These findings are necessary for improving our understanding of the characteristics of plant ecological stoichiometry and helping to plan measures for increasing N deposition.

Subtropical high-elevation mountain ecosystems are crucial for regional climate regulation and biodiversity conservation. However, the patterns of conifer radial growth in response to climate change in these regions remain unclear, significantly hindering the development of effective adaptive forest management strategies. This study examined Pinus taiwanensis and Cryptomeria fortunei, two dominant species in the Wuyi Mountains, using dendroclimatological methods to systematically analyze their long-term climate–growth relationships. The main findings include the following: (1) P. taiwanensis radial growth was significantly and positively associated with summer mean and maximum temperatures (in both the current and previous year), with no significant correlation to precipitation or minimum temperatures. In contrast, C. fortunei growth showed a positive relationship with previous autumn precipitation and a negative correlation with previous winter precipitation; (2) moving-window analysis revealed that P. taiwanensis maintained consistent temperature sensitivity, with an increasing response to summer warming in recent decades. Meanwhile, C. fortunei displayed phase-specific responses driven by precipitation and minimum temperatures. These results demonstrate divergent climate-response strategies among subtropical conifers in a warming climate: P. taiwanensis exhibits temperature-sensitive growth, whereas C. fortunei is primarily regulated by moisture availability. The findings provide critical insights for the adaptive management of subtropical montane forests, highlighting the need for species-specific strategies to maintain ecosystem services under future climate change.

Poplar is a globally important industrial tree species due to its fast growth and abundant applications. However, poplars require sufficient water during the growing season, and drought usually limits their production. Drought caused by climate change poses a serious threat to widely planted poplar plantations, making it crucial to clarify and improve the drought resistance of poplars. We employed two male poplar clones, namely, Siyang-1 (Populus × euramericana ‘Siyang-1’) and NL3804 (Populus deltoides ‘Nanlin 3804’), to investigate the growth and physiological responses of these clones to soil drought stress within 25 days. Under drought treatment, both clones experienced a significant reduction in height growth and biomass accumulation, with Siyang-1 exhibiting a more substantial decrease. Under drought treatment, Siyang-1 allocated more assimilates to roots than NL3804. Compared with Siyang-1, NL3804 wilted earlier and had a significantly higher wilting coefficient (p < 0.05). Siyang-1 had higher peroxidase (POD) activity in leaves under drought stress, while NL3804 had a greater increase in membrane permeability. Drought stress increased P absorption and decreased K absorption in both clones but had no significant effect on N absorption. The translocation of limited N and K resources into the stems and roots, as well as the increased uptake of P by the roots, can contribute to defending against drought for poplars. Siyang-1 enhances its drought resistance by modulating its nutrient status and slowing its growth rate, whereas NL3804 accumulates more biomass in the drought stage but perishes sooner, due to imbalances in water and antioxidant systems.

Atmospheric rainfall is one of the major sources of water and nutrient inputs in forest stands. Understanding the atmospheric rainfall partitioning and hydrochemical fluxes of forest stands is critical for forest management and monitoring regional atmospheric pollution, especially in high N deposition regions. In this study, annual rainfall collections were implemented to investigate rainfall partitioning, element concentrations, and element fluxes in an evergreen coniferous forest (ECF) stand, a deciduous broadleaved forest (DBF) stand, and open area field (OAF) in a high N deposition region, China. Rainfall in the ECF and DBF was partitioned into throughfall, stemflow, and interception loss, which accounted for 74.7%, 4.8%, and 20.5% of the gross annual rainfall in the ECF stand, respectively; and 79.8%, 5.8%, and 14.4% of the gross annual rainfall in the DBF stand, respectively. Rainfall physical partitioning chemical characteristics varied with forest stand type. The amount of throughfall and stemflow in the ECF stand was lower than that in the DBF stand; the interception loss in the ECF stand was higher than that in the DBF stand. Element concentrations and element fluxes increased as rainfall passed through forest canopies in the high N deposition region. The stemflow pH in the ECF was lower than that in the DBF stand, the concentrations of NO₃⁻-N, Cl⁻, and SO₄²⁻-S in stemflow in the ECF stand were higher than those in the DBF stand, and the concentrations of K⁺, Na⁺, Ca²⁺, Mg²⁺ and NH₄⁺-N in stemflow in the ECF stand were lower than those in the DBF stand. The inorganic N deposition was 52.7 kg ha⁻¹ year⁻¹ for the OAF, 110.9 kg ha⁻¹ year⁻¹ for the ECF stand, and 99.6 kg ha⁻¹ year⁻¹ for the DBF stand; stemflow accounted for 15.1% and 19.2% of inorganic N deposition in the ECF stand and the DBF stand, respectively. In the present study, given the similar rainfall characteristics and meteorological conditions, the differences in rainfall partitioning and chemical characteristics between the ECF stand and the DBF stand could largely be attributed to their differences in stand characteristics. The results of the study will facilitate a greater understanding of the atmospheric rainfall partitioning and hydrochemical fluxes of forest stands in a high nitrogen deposition region.

Passive acoustic monitoring (PAM) is an automatic and non-invasive method for long-term monitoring of bird vocal activity. PAM generates a large amount of data, and the automatic recognition of data poses significant challenges. BirdNET is a free-to-use sound algorithm. We evaluated the effectiveness of BirdNET in identifying the vocalizations of Chinese Bamboo Partridge (a Chinese endemic species) and proposed a random forest (RF) method to improve the result based on the detection of BirdNET. The diurnal and seasonal patterns of calling activity were described based on the identification results. The results showed that the recall of BirdNET-Analyzer was 16.6%, the precision of BirdNET-Analyzer-XHS was 50.8%, and the recall and precision of the RF model were 75.2% and 74.4%, respectively. The diurnal vocal activity of the Chinese Bamboo Partridge showed a bimodal pattern, with peaks around sunrise and sunset and low vocal activity during the central hours of the day. The seasonal vocal activity displayed a unimodal pattern, with a peak in vocal activity during April and May. This study used the Chinese Bamboo Partridge as an example and proposes an improved RF model, built on BirdNET recognition results, for species identification, providing a practical approach for recognizing the vocalizations of regional species.