Projecting future habitat quality of three midwestern reservoir fishes under warming conditions

Rising temperatures caused by climate change are likely to affect cool‐water and warm‐water fishes differently. Yet, forecasts of anticipated temperature effects on fishes of different thermal guilds are lacking, especially in freshwater ecosystems. Towards this end, we used spatially explicit, growth rate potential (GRP) models to project changes in seasonal habitat quality for a warm‐water piscivore (largemouth bass Micropterus salmoides), a cool‐water piscivore (walleye Sander vitreus) and a hybrid piscivore (saugeye S. vitreus × S. canadensis) in two Midwestern reservoirs. We assessed habitat quality for two periods (early and middle 21st century) under two realistic greenhouse gas emission scenarios (a mid‐century emissions peak and a rapid continuous increase in emissions). Largemouth bass were projected to experience enhanced or slightly reduced habitat during all seasons, and throughout the mid‐21st century. By contrast, walleye habitat was projected to decline with anticipated warming, except during the spring in the smaller of our two study reservoirs and during the fall in the larger of our two study reservoirs. Saugeye habitat was projected to either increase modestly or decline slightly during the spring and fall and declines in habitat quality and quantity that were smaller than those for walleye were identified during summer. Collectively, our findings indicate that climate warming will differentially alter habitat suitability for reservoir piscivores, favouring warm‐water species over cool‐water species. We expect these changes in habitat quality to impact the dynamics of reservoir fish populations to varying degrees necessitating the consideration of climate when making future management decisions.     

吕梁山地区植被物候变化及对气候的响应

吕梁山地区地形垂直差异明显,植被对气候变化反应敏感,研究吕梁山地区植被物候变化,探索植被物候变化与气候的响应关系,旨在为高海拔山区植被物候研究和生态治理提供借鉴。基于2000—2015年MODIS NDVI时间序列数据,通过动态阈值法提取吕梁山地区的植被物候,对气温、降水进行空间插值,并对植被2个关键物候期与气候因素进行偏相关分析。结果表明：（1）植被生长季开始日期(the start of the growing season,SOS)提前的区域约占85.7%,其中16.2%显著提前;植被生长季结束日期(the end of the growing season,EOS)推迟的区域约占90.6%,其中33.3%显著推迟。（2）区内74.8%、87.7%植被SOS分别与气温、降水呈负相关,气温升高或降水增加,植被SOS提前。植被SOS在高海拔山区受4月气温影响显著,而低海拔地区受4月降水影响显著。（3）区内72.6%、65.1%植被EOS分别与气温、降水呈正相关,气温升高或降水增加,植被EOS推迟。植被EOS在北部和西部地区受11月气温影响显著,而高海拔地区受9月降水影响显著。2000—2015年吕梁山地区植被物候发生显著变化,各地区对气温、降水的响应不同,研究结果可为区域物候、气候变化研究和陆地生态治理提供科学依据。     

撤销学位论文学术影响力研究

[目的/意义]分析被撤销学位的博硕士学位论文分布情况,揭示其在学术系统的不良影响,为管理部门制订相关政策提供建议和参考,为具体实践提供方法和策略。[方法/过程]通过媒体的公开报道获得撤销学位案例,在学位论文数据库和网络阅读分享平台中获得撤销学位论文的分布数据、引用数据和Altmetrics数据,分析撤销学位论文的学术影响,提出治理策略。[结果/结论]论文的残留率为75%,即有75%的学位论文在学位被撤销后仍分布在各数据平台中;论文的净化率为36%,即有36%的撤销学位论文被数据平台删除;文献计量分析发现,有58%撤销学位论文被引用过,其中33%的引用发生在撤销之后;Altmetrics分析发现,84%撤销学位论文在网上被上传、收藏、分享、评论和转载,其中有24%的论文在撤销后仍被上传。最后从科研诚信教育和学术不端行为惩戒两个角度提出治理策略。     

基于低影响开发的校园雨水控制及效益分析

以安徽理工大学为研究对象,应用4种低影响开发(LID)方案(植草沟、下沉式绿地、雨水罐和植草沟-下沉式绿地-雨水罐组合)构建雨洪管理模型(SWMM),模拟不同雨水重现期下各种LID方案的水文和水质性能,并评价了经济效益.结果表明:植草沟的径流削减效率最好,可延迟流量峰现时间,且能有效地削减污染负荷;除雨水罐外,另外3种LID实践方案具有良好的环境效益;从成本效益上分析,下沉式绿地和组合LID实践方案的污染物控制效果较好,但其单位削减率成本高,植草沟对污染物控制效果不理想,但其具有最低的单位削减率;若想取得较好的污染物控制效果,则需要投入更大的成本,可以采用下沉式绿地或组合LID实践方案,下沉式绿地或组合LID实践方案不仅能有效削减峰值流量,缓解城市排水管网负荷,且对污染物的削减效果较好.可为中国校园中LID实践的应用决策提供理论支持.     

Impact of climate change on maize yield in China from 1979 to 2016

Climate change severely impacts agricultural production, which jeopardizes food security. China is the second largest maize producer in the world and also the largest consumer of maize. Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics. Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square(FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results:(1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China. For every 1°C increase in temperature, the maize yield was reduced by 5.19 kg 667 m–2(1.7%). Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible. For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m–2(0.014%).(2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China. In this region, a 1°C increase in temperature resulted in a 7.49 kg 667 m–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant. For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m–2 in southern China and 0.066 kg 667 m–2 in northern China.(3) The resilience of the maize crop to climate change is strong. The marginal effect of temperature in both southern and northern China during the 1990–2016 period was smaller than that for the 1979–2016 period.     

气候变化情景下流苏香竹潜在分布区预测

流苏香竹（Chimonocalamus fimbriatus）是云南特有珍稀竹种，主要分布于云南西南部。文章以野外调查获取的流苏香竹分布信息为主，运用最大熵模型（MaxEnt）同时结合地理信息系统（ArcGIS），基于19个气候因子，预测其在当前及未来气候变化情景下的潜在分布区。结果表明：当前流苏香竹的高适生区和中适生区主要分布于德宏州、保山市和临沧市等地，除迪庆州、丽江市和昭通市外，云南其他区域均有低适生区零星分布。在未来2050s和2070s的2个时间段，基于2种不同共享社会经济路径（SSP1-2.6和SSP5-8.5），流苏香竹的高适生区面积呈减少的趋势，尤其是SSP5-8.5路径下，高适生区面积仅为当前的12.51%（2050s）和18.63%（2070s）；中、低适生区在SSP1-2.6路径下，显著扩张（2050s）或略微扩张（2070s），在SSP5-8.5路径下，则大幅收缩。流苏香竹野外实际分布区及其潜在分布区均以斑块状为主，可能与云南特殊的地形、地貌有关。影响流苏香竹分布的主导气候因子为最湿月份降水量、最暖月份最高温度、最干季度降水量和平均气温日较差。流苏香竹对气候变化比较敏感，根据其野外分布状况，建议以就地保护为主、迁地保护为辅，在其潜在适生区内适当引种栽培。     

湘西州1960—2017年气候变化及对农业的影响

为掌握全球气候变暖背景下的湘西州气候变化特征，减缓和适应气候变化对农业生产带来的不利影响。[方法]本研究以湘西州8个县（市）气象台站1960—2017年逐日气象观测数据及古丈国家农业气象一级观测站的观测数据为基础，利用滑动平均、线性拟合、M-K检验、小波分析等，研究1960—2017年湘西州气温、降水、相对湿度、日照时数的变化特征及对农业的影响。[结论]结果表明：年平均气温升温趋势明显，1960—2017年升温0.81℃；气温的年代际变化明显，21世纪后气温明显上升；冬季、春季升温突出，夏季升温不明显；年降水量无显著趋势变化，年际波动较大；相对湿度、日照时数呈减少趋势。水稻、油菜生育期明显缩短，产量下降。[结果]气候变化对农业生产布局、作物生长、产量品质等均有一定影响。     

作物模型中单叶最大光合作用速率的温度响应修订

作物的光合作用对温度变化敏感,其温度依存性随品种、生长环境的变化而改变。基于光效率模型的作物生长模型,在应用中很少对光合作用的温度影响参数值进行订正,且在全生育期使用相同的参数值,难免会增加干物质模拟的误差。为此,本文以ORYZA2000模型为例,提出了一种修订光合作用温度影响参数值的方法。为确定方法的有效性,结合2012年和2013年水稻品种两优培九的温度梯度控制实验,首先利用抽穗开花期光合作用观测曲线提取了不同温度水平的光合作用参数值,然后结合Arrhenius方程和Peaked方程建立了温度敏感性参数的温度影响方程。将这些方程代入机理性光合作用模型,模拟了单叶最大光合作用速率与温度的曲线关系。最后,以归一化后的曲线关系修订作物模型参数值,并利用两年地上部分生物量(WAGT)观测值对其验证。结果显示,两优培九单叶最大总光合作用速率随温度的变化关系不同于ORYZA2000的默认设置,修订后的最适温度为38~40°C,高于默认值。在10~20°C的低温段,修订后的温度影响系数低于默认值。从WAGT模拟值的相对误差看,修订后较修订前平均降低约3.3%。本研究为改进干物质模拟精度和分析不同品种光合作用的温度依存性提供了重要参考。     

滦河流域气候变化与人类活动对径流的影响

以滦河流域为研究区域,应用敏感性分析和双累积曲线法分析气候变化和人类活动对研究区径流变化的影响。结果表明:研究区流域径流存在明显的下降趋势,与基准期(1956—1979年)相比,变化期(1980—2013年)径流量减少了52.59mm(50.43%);滦河流域径流对降水的敏感性系数Q/P为0.336 1,对潜在蒸散发的敏感性系数Q/E_0为-0.123 5,气候变化影响量为22.23mm;滦河流域径流变化过程中,人类活动影响量为32.07mm,其贡献率为57.26%,远大于气候变化的影响39.69%,人类活动的影响是导致滦河流域径流减少的主要因素。     

The decline of fisheries on the Madeira River,Brazil: The high cost of the hydroelectric dams in the Amazon Basin

Despite being considered beneficial by providing a clean and renewable source of energy, the construction of hydroelectric dams has extremely negative implications for Amazonian fisheries. This study investigated the impacts of the Santo Antônio and Jirau hydroelectric dams on the fishery stocks of the Madeira River. This investigation was based on fish catch data from the Z‐31 fishing colony, located in the municipality of Humaitá, in Amazonas State, Northern Brazil. Data were collected daily and provided information on the date of return from each trip, the fish species targeted, and the total catch (kg) between January 2002 and September 2017. The results indicated reductions of 39% in the mean annual catch and 34% in the mean monthly catches. These results highlight the high price paid by local fish communities for the development of hydroelectric power in the Amazon basin.