Precipitation and Reproduction are Negatively Associated with Female Turkey Survival

Understanding how reproductive tradeoffs act in concert with abiotic elements to affect survival is important for effective management and conservation of wildlife populations, particularly for at-risk or harvested species. Wild turkeys (Meleagris gallopavo) are a high-interest species for consumptive and non-consumptive uses, and female survival is a primary factor influencing turkey population dynamics. We radio-tracked and collected survival data on 140 female Merriam's wild turkeys (M. g. merriami) in the northern Black Hills, South Dakota, USA, 2016–2018. We developed and compared a set of candidate models to evaluate how nest incubation, brood rearing, and precipitation could be associated with female survival. Increased time spent incubating was associated with reduced female survival. Additionally, daily precipitation was associated with reduced survival of incubating females. Seasonal survival was lowest during spring and winter. A female that did not incubate a nest was predicted to have a higher rate of annual survival (0.53, 85% CI = 0.48–0.59) than a female that incubated a single nest (0.47, 85% CI = 0.42–0.53). Despite the relative proximity of population segments, we estimated that annual survival for nesting and non-nesting females was lower in the northern Black Hills compared to annual female survival in the southern Black Hills, underscoring the need for region-specific data when possible. © 2020 The Wildlife Society.     

Precipitation‐drainage cycles lead to hot moments in soil carbon dioxide dynamics in a Neotropical wet forest

Soil CO₂ concentrations and emissions from tropical forests are modulated seasonally by precipitation. However, subseasonal responses to meteorological events (e.g., storms, drought) are less well known. Here, we present the effects of meteorological variability on short‐term (hours to months) dynamics of soil CO₂ concentrations and emissions in a Neotropical wet forest. We continuously monitored soil temperature, moisture, and CO₂ for a three‐year period (2015–2017), encompassing normal conditions, floods, a dry El Niño period, and a hurricane. We used a coupled model (Hydrus‐1D) for soil water propagation, heat transfer, and diffusive gas transport to explain observed soil moisture, soil temperature, and soil CO₂ concentration responses to meteorology, and we estimated soil CO₂ efflux with a gradient‐flux model. Then, we predicted changes in soil CO₂ concentrations and emissions under different warming climate change scenarios. Observed short‐term (hourly to daily) soil CO₂ concentration responded more to precipitation than to other meteorological variables (including lower pressure during the hurricane). Observed soil CO₂ failed to exhibit diel patterns (associated with diel temperature fluctuations in drier climates), except during the drier El Niño period. Climate change scenarios showed enhanced soil CO₂ due to warmer conditions, while precipitation played a critical role in moderating the balance between concentrations and emissions. The scenario with increased precipitation (based on a regional model projection) led to increases of +11% in soil CO₂ concentrations and +4% in soil CO₂ emissions. The scenario with decreased precipitation (based on global circulation model projections) resulted in increases of +4% in soil CO₂ concentrations and +18% in soil CO₂ emissions, and presented more prominent hot moments in soil CO₂ outgassing. These findings suggest that soil CO₂ will increase under warmer climate in tropical wet forests, and precipitation patterns will define the intensity of CO₂ outgassing hot moments.     

Annual ecosystem respiration is resistant to changes in freeze–thaw periods in semi‐arid permafrost

Warming in cold regions alters freezing and thawing (F–T) of soil in winter, exposing soil organic carbon to decomposition. Carbon‐rich permafrost is expected to release more CO₂ to the atmosphere through ecosystem respiration (Re) under future climate scenarios. However, the mechanisms of the responses of freeze – thaw periods to climate change and their coupling with Re in situ are poorly understood. Here, using 2 years of continuous data, we test how changes in F–T events relate to annual Re under four warming levels and precipitation addition in a semi‐arid grassland with discontinuous alpine permafrost. Warming shortened the entire F–T period because the frozen period shortened more than the extended freezing period. It decreased total Re during the F–T period mainly due to decrease in mean Re rate. However, warming did not alter annual Re because of reduced soil water content and the small contribution of total Re during the F–T period to annual Re. Although there were no effects of precipitation addition alone or interactions with warming on F–T events, precipitation addition increased total Re during the F–T period and the whole year. This decoupling between changes in soil freeze – thaw events and annual Re could result from their different driving factors. Our results suggest that annual Re could be mainly determined by soil water content rather than by change in freeze – thaw periods induced by warming in semi‐arid alpine permafrost.     

Precipitation controls seed bank size and its role in alpine meadow community regeneration with increasing altitude

The Tibetan Plateau has undergone significant climate warming in recent decades, and precipitation has also become increasingly variable. Much research has explored the effects of climate change on vegetation on this plateau. As potential vegetation buried in the soil, the soil seed bank is an important resource for ecosystem restoration and resilience. However, almost no studies have explored the effects of climate change on seed banks and the mechanisms of these effects. We used an altitudinal gradient to represent a decrease in temperature and collected soil seed bank samples from 27 alpine meadows (3,158–4,002 m) along this gradient. A structural equation model was used to explore the direct effects of mean annual precipitation (MAP) and mean annual temperature (MAT) on the soil seed bank and their indirect effects through aboveground vegetation and soil environmental factors. The species richness and abundance of the aboveground vegetation varied little along the altitudinal gradient, while the species richness and density of the seed bank decreased. The similarity between the seed bank and aboveground vegetation decreased with altitude; specifically, it decreased with MAP but was not related to MAT. The increase in MAP with increasing altitude directly decreased the species richness and density of the seed bank, while the increase in MAP and decrease in MAT with increasing altitude indirectly increased and decreased the species richness of the seed bank, respectively, by directly increasing and decreasing the species richness of the plant community. The size of the soil seed bank declined with increasing altitude. Increases in precipitation directly decreased the species richness and density and indirectly decreased the species richness of the seed bank with increasing elevation. The role of the seed bank in aboveground plant community regeneration decreases with increasing altitude, and this process is controlled by precipitation but not temperature.     

Preparation of a recyclable novel thermoresponsive affinity copolymer and its application towards ε-polylysine purification

Thermo-responsive polymers have great potential for industrial applications of bio-separation and purification. However, the poor affinity and low recovery of thermoresponsive copolymers are the main factors limiting their large-scale application. In this paper, a recyclable thermoresponsive affinity copolymer (P_NHM-IDA-Ni²⁺) was prepared by immobilizing nickel ions (Ni²⁺) on copolymer P_NHM, and P_NHM-IDA-Ni²⁺ was applied to the purification of ε-polylysine. The lower critical solution temperature (LCST) of P_NHM and P_NHM-IDA-Ni²⁺ were 31.0 °C and 34.0 °C, respectively. Additionally, the recoveries of both copolymers were over 95.0%. The main parameters, such as pH were investigated to optimize the adsorption conditions. In addition, the Langmuir and Freundlich adsorption models were used to predict the maximum adsorption capacity of ε-polylysine. The results of the affinity precipitation demonstrated that the maximum adsorption capacity was 42.9 mg/g, and the adsorption was considered to follow the mono-layer model. The thermodynamic parameters (ΔG⁰, ΔH⁰ and ΔS⁰) of the ε-polylysine adsorption indicated that the adsorption was spontaneous and exothermic. The maximum elution recovery (93.5%) was achieved at pH 5.0 with 0.2 M imidazole. The results of tricine-SDS-PAGE and HPLC (Purity: increased from 84% to 99%) showed that the ε-polylysine was well separated from the crude extract by using the affinity copolymer P_NHM-IDA-Ni²⁺.     

自体富血小板凝胶联合冷沉淀制剂对糖尿病足溃疡患者创面愈合、血管生成因子及生活质量的影响

目的:探讨自体富血小板凝胶联合冷沉淀制剂对糖尿病足溃疡患者创面愈合、血管生成因子及生活质量的影响。方法:选取西宁市第一人民医院于2016年8月～2018年8月间收治的糖尿病足溃疡患者54例,依据数表法将患者随机分为对照组(n=27)和观察组(n=27)。对照组采用常规基础治疗,观察组在对照组基础上序贯使用自体富血小板凝胶联合冷沉淀制剂治疗。比较两组疗效、溃疡愈合时间、住院时间,比较两组患者治疗前及治疗20d后的肉芽组织中碱性成纤维细胞生长因子(bFGF)和血管内皮细胞生长因子(VEGF)表达水平以及糖尿病患者生存质量特异性量表评分。结果:观察组总有效率高于对照组(P0.05)。观察组溃疡愈合时间和住院时间均明显短于对照组,差异有统计学意义(P0.05)。治疗20d后,两组患者肉芽组织bFGF、VEGF表达水平均明显升高(P0.05),且观察组肉芽组织bFGF、VEGF表达水平均明显高于对照组(P0.05)。治疗20d后,两组患者生理功能、社会关系、心理或精神以及治疗影响四个维度评分均明显下降(P0.05),且观察组低于对照组(P0.05)。结论:自体富血小板凝胶联合冷沉淀制剂治疗糖尿病足溃疡疗效确切,可提高患者生活质量,可促进肉芽组织中血管生成和创面愈合。     

Belowground biomass of alpine shrublands across the northeast Tibetan Plateau

Although belowground biomass (BGB) plays an important role in global cycling, the storage of BGB and climatic effects on it are remaining unclear. With data from 49 sites, we aimed to investigate BGB and its climatic controls in alpine shrublands in the Tibetan Plateau. Our study showed that the BGB (both grass‐layer and shrub‐layer biomass) storage in the alpine shrublands was 67.24 Tg, and the mean BGB density and shrublands area were 1,567.38 g/m² and 4.29 × 10⁴ km², respectively. Shrub layer had a larger BGB stock and accounted for 66% of total BGB this area, while only 34% was accumulated in the grass layer. BGB of the grass layer in the Tibetan Plateau shrublands was larger than that of Tibetan alpine grasslands, indicating that shrubland ecosystem played a critical importance role in carbon cycle on the Tibetan Plateau. The BGB in the grass layer and shrub layer demonstrated different correlations with climatic factors. Specifically, the effects from mean annual temperature on shrub‐layer BGB were not significant, similarly to the relationship between mean annual precipitation and grass‐layer BGB. But shrub‐layer BGB had a significantly positive relationship with mean annual precipitation (p < .05), while grass‐layer BGB showed a trend of decrease with increasing mean annual temperature (p < .05). Consequently, the actual and potential increases of BGB varied due to different increases of mean annual precipitation and temperature among different areas of the Tibetan Plateau. Therefore, in the warmer and wetter scenario, due to contrary relationships from mean annual precipitation and temperature on shrub‐layer BGB and grass‐layer BGB, it is necessary to conduct a long‐term monitoring about dynamic changes to increase the precision of assessment of BGB carbon sequestration in the Tibetan Plateau alpine shrublands.