气候变化情景下毛竹潜在分布及动态预测

为探究毛竹的潜在分布及其动态变化，并确定对其分布起主导作用的环境变量，文章基于MaxEnt预测模型，利用环境变量图层及316个毛竹分布点数据研究毛竹地理分布的变化。结果显示：1）限制毛竹分布的主要环境变量为最干月降水量、年均降水量、最冷月最低温、年平均温、温度年较差和海拔；2）当前毛竹的潜在适生区主要位于中国东南部，与亚热带季风气候区大致重叠，高适生区主要位于总适生区的东部和西北部；3）在未来气候情景下，毛竹总适生区面积有所缩减，各不同等级适生区面积变化大，其中高适生区面积大幅度缩减。研究获得的毛竹适生区变化趋势可为毛竹培育、引种以及入侵防治提供参考。     

Examining horizontal and vertical social ties to achieve social–ecological fit in an emerging marine reserve network

1. Most MPA networks are designed only with ecological processes in mind to increase their conservation utility. However, since MPA networks often involve large geographic areas, they also affect and involve multiple actors, institutions, and policy sectors.
2. A key challenge when establishing an effective MPA network is to align the ‘social system’ with the biophysical MPA network (the ‘ecological system’). This challenge is often denoted as ‘social–ecological fit’.
3. Facilitating collaborative social interactions among various actors and stakeholders (social connectivity) is equally as important as accomplishing ecological connectivity. New analytical approaches are required to effectively examine this ‘social’ dimension of fit.
4. An emerging marine reserve network in Jamaica and the recent invasion of Indo‐Pacific lionfish are used as a case study to: (1) examine the extent to which horizontal and vertical social ties bring local and national actors together to collaborate, coordinate, and share knowledge; and (2) assess the extent to which different attributes and features of such multilevel social networks may enhance or inhibit particular aspects of social–ecological fit.
5. Findings suggest that multilevel linkages have played the greatest role in relation to enhancing fit in the marine reserve network in the context of the recent lionfish invasion. However, the long‐term propensity of the multi‐actor and multilevel networks to enhance social–ecological fit is uncertain given the prevalence of weak social ties, lack of a culture of information sharing and collaboration, and limited financial resources.

     

Artificial neural network modeling of microbial community structures in the Atlantic Forest of Brazil

Microbial communities vary across the landscape in forest soils, but prediction of their biomass and composition is a difficult challenge due to the large numbers of variables that influence their community structures. Here we examine the use of artificial neural network (ANN) models for extraction of patterns among soil chemical variables and microbial community structures in forest soils from three regions of the Atlantic Forest of Brazil. At each location, variations in soil chemical properties and FAME profiles of microbial community structures were mapped at 20 × 20 m intervals within 10 ha parcels. Geostatistical analyses showed that spatial variability in soil physical and chemical variables could be mapped at scale distances of 20 m, but that FAME profiles representing the microbial communities were highly variable and had no spatial dependence at the same scale in most cases. RDA analysis showed that FAME signatures representing different microbial groups were positively associated with soil pH, OM, P and base cations concentrations, whereas microbial biomass was negatively associated with the same environmental factors. In contrast, ANN models revealed clear relationships between microbial community structures at each parcel location, and generated verifiable predictions of variations in FAME profiles in relation to soil pH, texture, and the relative abundances of base cations. The results suggest that ANN modeling provides a useful approach for describing the relationships between microbial community structures and soil properties in tropical forest soils that were not able to be captured using geostatistical and RDA analyses.     

大兴安岭北部林区森林防火基础设施建设成效及对策

大兴安岭北部林区森林防火基础设施建设项目是建国后国家一次性用于国有林区森林防火投资最大的基础设施建设工程。介绍了该项目建设的基本情况,总结了主要建设成效,分析了存在问题,提出了相关对策建议。     

Intercropping soybean and palisade grass for enhanced land use efficiency and revenue in a no till system

Integrated no-till crop and livestock production systems may help rejuvenate degraded pastures, increase land use efficiency (LUE), and increase enterprise revenue. Our objectives were to evaluate: (1) planting date effects on seed yield and nutrient concentration of an early-maturing, no-till system (NTS) soybean (Glycine max) when intercropped with palisade grass (Brachiaria brizantha); (2) dry matter production and protein concentration of the grass pasture after soybean harvest; and (3) overall revenue and LUE for the intercrop system. Experiments were performed during two growing seasons in Botucatu, Brazil using a randomized complete block experimental design. When palisade grass and soybean were sown simultaneously, soybean yield averaged 3.28 Mg ha⁻¹. Similar seed yields were observed when palisade grass was planted either 30 d after soybean emergence (DAE) (3.29 Mg ha⁻¹) or at the soybean reproductive stage R6 (full seed) (3.50 Mg ha⁻¹). Monocrop soybean yield averaged 3.50 Mg ha⁻¹. First cut dry matter forage production was greater when palisade grass was sown at the same time as soybean or 30 DAE of soybean. This indicates that interseeding palisade grass with soybean does not significantly affect soybean nutrition or yield. Intercropping did increase LUE and resulted in 1.6 times more revenue than soybean alone. However, sowing palisade grass at the soybean reproductive stage R6 (full seed) significantly reduced the forage yield compared to early planting.     

兰州市高海拔旱作区娃娃菜栽培技术

在分析兰州市高海拔地区自然条件的基础上,有针对性地提出了高海拔旱作区娃娃菜栽培技术,以供参考。     

左右岸省界缓冲区水质达标评价方法研究

左右岸省界缓冲区作为协调省际间用水关系的重要水域,其水质达标评价及污染责任划分是流域限制纳污红线制度实施的重要内容。从左右岸省界缓冲区的相关概念出发,根据省份的位置关系将其分为缓冲区完全在两省省界上、缓冲区部分在两省省界上以及缓冲区在多省交界上三种情形,并结合左右岸省界缓冲区特点确定调整浓度核算法、代表断面判断法、限制排污总量-污染物入河量评估法等水质达标评价方法,以判断左右岸省份缓冲区的水质达标情况,从而划分缓冲区左右岸省份的污染责任。实例验证模拟显示,确定的方法切实可行,研究方法可为流域污染责任划分提供技术支撑,从而促进限制纳污制度的顺利实施。     

沈阳铁西区装备制造产业聚集实证分析

铁西区通过打造装备制造业产业聚集区。形成了高档数控机床、通用石化装备等六大主导产业以及电气及新能源等五大千亿产业集群，成为我国老工业基地振兴的区域典范。介绍铁西装备制造业聚集区发展现状，采用区位熵法测算沈阳装备制造业的产业集中度，对全市装备制造业的现状及问题进行分析，得出相应结论。     

中国玉米市场形势分析与未来10年展望

2013年,中国玉米产量再创新高,消费需求相对低迷,进出口同比下降,供求关系较为宽松,价格总体弱势运行。预计未来10年,中国玉米生产继续稳步增长,消费需求增速较快但将明显放缓,价格总体继续上涨,玉米进口将进一步扩大。最后,指出影响未来玉米市场走势的因素主要包括气象、政策、贸易以及通胀、汇率等不确定性因素。     

新疆南部农区鼠害调查与成因分析

南疆农区鼠害严重,但基础资料不足。为摸清当地鼠害发生特点,提供有效治理依据,本研究于2018年-2019年在南疆5地州39乡64村开展实地与问卷调查,并采用夹捕法调查害鼠种群构成。结果表明,南疆5地州农村普遍遭受鼠害影响,喀什与和田地区农田受害比例达89.4%,问卷结果表明农户和农田鼠害发生率均大于75%,且西部地区重于东部,约一半受访农户估计每年因鼠害损失超过500元。褐家鼠Rattus norvegicus是农户主要害鼠,占比超过70%;农田则以小家鼠Mus musculus和乌拉尔姬鼠Apodemus uralensis为主。这些结果表明,南疆农区鼠害处于重发态势,褐家鼠是主要鼠害来源,并有外来入侵风险。下一步应聚焦于监测主要害鼠种群动态规律,阐明褐家鼠来源和侵入机制,并探索建立适于当地的害鼠防治模式。