西藏唐北地区湖泊动态及空间格局预测

本研究评估了西藏唐古拉山以北地区(唐北地区)湖泊动态并预测了湖泊空间格局变化.使用面向对象分类和光谱角向量变化检测方法生成了2000-2015年西藏唐北地区每5年一期的生态系统分布数据.以此为基础,分析了湖泊与其他生态系统之间的转换和空间格局特征,评估了湖泊空间格局的动态及其与相关自然地理因素的关系.通过增强回归树识别了不同因素对湖泊动态的贡献,使用GEOMOD模型预测了湖泊到2030年的空间变化.结果表明:唐北地区在2000-2015年间湖泊增加了14.2%,是唐北地区生态系统变化的主要形式之一.区域内15个面积大于10 km2的湖泊有10个增加,另有5个减少,且缩减量较低.通过空间格局分析发现,唐北地区湖泊斑块表现为面积和数量同时增加,大斑块面积比重略有上升.扩张幅度高的湖泊多分布于海拔高、坡度大、温度低、降水少、距离冰川近的区域.位于现有湖泊周边、温度低、降水少、坡度小的区域转变为湖泊的几率较高.根据过去15年的趋势,到2030年,唐北地区湖泊将继续增加119 km2,主要变化形式从大湖扩张转变为小型水面扩张.     

以国家公园为主体的自然保护地体系立法思考

实现十九大报告提出的建立以国家公园为主体的自然保护地体系的改革目标需要法治保障。建设自然保护地体系涉及的不同生态系统和多个管理部门、多方利益主体, 是一个巨大的复杂系统, 需要进行整体性、系统性的立法研究。目前, 国家正在推进国家公园体制改革并已将《国家公园法》列入十三届全国人大常委会立法计划。更需要我们从自然保护地立法体系建设的高度, 正确处理《国家公园法》与未来可能制定的《自然保护地法》的关系, 在《国家公园法》制定过程中为今后出台《自然保护地法》预留空间, 并建立相应的衔接机制, 统筹谋划并协同推进国家公园法与自然保护地立法。     

中国自然保护地空间重叠分析与保护地体系优化整合对策

自然保护地体系的构建是国际社会高度重视的生物多样性保护策略。近年来, 中国已关注到自然保护地空间重叠交叉的问题, 并出台了《关于建立以国家公园为主体的自然保护地体系的指导意见》。为落实这一战略, 需要对现有保护地的彼此关系与空间分布进行系统研究。为此, 本研究收集了8,572个不同类型和级别自然保护地的坐标、生态系统类型、行政区域及边界等信息, 筛选出1,532个具有空间重叠、管理部门交叉的自然保护地, 计算地理集中指数并采用ArcGIS软件进行了核密度分析, 得出空间重叠保护地分布的生态地理区、生态系统类型、交叉管理部门、所在省份等空间分布特点。研究结果显示: (1)鲁中山区、太行山、大别山、天目山-怀玉山、皖江等生态功能区的自然保护地重叠最为严重(核密度Mean > 6, Max > 8), 其中太行山区、大别山区、天目山-怀玉山区为重叠保护地密度高的生物多样性优先保护区, 目前10个国家公园试点区域中仅大熊猫国家公园体制试点区、湖南南山国家公园体制试点区、钱江源国家公园体制试点区三处位于保护地重叠高密度区; (2)原主管部门中, 原国家林业局与住房和城乡建设部的交叉管理保护地数量最多, 为294个; (3)黑龙江、安徽、山东、河南、湖北、湖南等省范围内的自然保护地空间重叠状况明显高于其他省区, 而晋冀豫与皖鄂赣这两处三省交界处重叠程度更高, 其他多处三省交界区域也存在保护地的中度重叠。故上述生态地理区、原主管部门与行政区应作为中国自然保护地体系优先普查区域与优化整合重点对象。基于重叠保护地核密度热点区、生物多样性保护优先区与生态系统文化服务的分析框架, 本研究按照国家公园、自然保护区、自然公园三类, 对不同生态功能区自然保护地优化整合优先性与类型提出了初步建议, 以期为当前中国自然保护地体系改革的紧迫需求提供参考。     

Carbon accumulation and vertical accretion in a restored versus historic salt marsh in southern Puget Sound,Washington, United States

Few comparisons exist between vertical accretion (VA) and carbon accumulation rates (CARs) in restored versus historic (i.e. reference) marshes. Here, we compare these processes in a formerly diked, sparsely vegetated, restored salt marsh (Six Gill Slough, SG), whose surface is subsided relative to the tidal frame, to an adjacent, relatively pristine, historic salt marsh (Animal Slough, AS). Six sediment cores were collected at both AS and SG approximately 6 years after restoration. Cores were analyzed for bulk density (BD), % loss of ignition, % organic carbon, and ²¹⁰Pb. We found that sharp changes in BD in surface layers of SG cores were highly reliable markers for the onset of restoration. The mean VA since restoration at SG (0.79 [SD = 0.29] cm/year) was approximately twice that of AS (0.41 [SD = 0.16] cm/year). In comparison, the VA at AS over 50 years was 0.30 (SD = 0.09) cm/year. VA consisted almost entirely of inorganic sediment at SG whereas at AS it was approximately 55%. Mean CARs at SG were somewhat greater than at AS, but the difference was not significant due to high variability (SG: 81–210 g C m^?2 year^?1; AS: 115–168 g C m^?2 year^?1). The mean CAR at AS over the past 50 years was 118 (SD = 23) g C m^?2 year^?1. This study demonstrates that a sparsely vegetated, restored salt marsh can quickly begin to accumulate carbon and that historic and restored marshes can have similar CARs despite highly divergent formation processes.     

Adaptive management assists reintroduction as higher tides threaten an endangered salt marsh plant

In theory, extirpated plant species can be reintroduced and managed to restore sustainable populations. However, few reintroduced plants are known to persist for more than a few years. Our adaptive‐management case study illustrates how we restored the endangered hemiparasitic annual plant, Chloropyron maritimum subsp. maritimum (salt marsh bird's beak), to Sweetwater Marsh, San Diego Bay National Wildlife Refuge, California, United States, and used monitoring and experimentation to identify the factors limiting the reintroduced population. After extirpation in 1988, reintroduction starting that year led to a resilient, genetically diverse population in 2016 (a “boom” of approximately 14,000) that rebounded from a “bust” (62 in 2014). Multiple regressions attributed 82% of the variation in population counts to tidal amplitude, rainfall, and temperature. Populations of salt marsh bird's beak crashed when the diurnal tide range peaked during the 18.6‐year lunar nodal cycle (a rarely considered factor that periodically added approximately 12 cm to tidal ranges). We explain booms as follows: During smaller tidal amplitudes, above‐average rainfall could desalinize upper intertidal soils and stimulate salt marsh bird's beak germination. Then, moderate temperature in May favors growth to reproduction in June. In addition, salt marsh bird's beak needs a short and open canopy of native perennial plants, with roots to parasitize (not non‐native annual grass pseudohosts) and nearby upland soil for a preferred pollinator, ground‐burrowing bees. Although our reintroduced salt marsh bird's beak population is an exceptional case of persistence, this rare species‐specific environmental and biological requirement makes it vulnerable to rising sea levels and global warming.     

An effective method for ecosystem‐scale manipulation of bird abundance and species richness

Manipulation experiments are a cornerstone of ecological research, but can be logistically challenging to execute—particularly when they are intended to isolate the ecological role of large, vagile species, like birds. Despite indirect evidence that birds are influential in many ecosystems, large‐scale, multi‐year bird manipulation experiments are rare. When these studies are conducted, they are typically realized with caged or netted exclosures, an approach that can be expensive, risky for wildlife, and difficult to maintain. In cases where caged exclosures are not appropriate, alternate approaches are needed to allow rigorous empirical studies on the ecological role of birds. Here, we present and validate a method for experimentally increasing the abundance and richness of birds at the scale of entire aquatic ecosystems. Unlike bird exclusion, this approach is experimentally tractable, appealing to land managers, and possible to deploy over large spatial scales. We tested the efficacy of our approach for increasing bird abundance and species richness at 16 central California ponds. Based on bird visitation data obtained by summer camera trapping, our approach significantly increased bird species richness and abundance at manipulated ponds compared to control ponds. Attractant treatments mitigated the negative effects of a major drought on bird species richness and generated a near doubling of bird abundance in the presence of attractants. Treatments had no effect on most mammal species, with the exception of ground squirrels, which increased in abundance in the presence of attractants. These results suggest that attractants are effective in increasing bird abundance and richness. We encourage researchers to consider this approach for experimentally isolating the ecological role of birds in aquatic and open terrestrial ecosystems, especially in cases where cost or logistical constraints preclude the use of caged or netted exclosures.     

淀粉酶高产菌株的筛选、紫外诱变及产酶条件优化

【背景】提高淀粉酶的稳定性进而适应多变的工业生产条件,是淀粉酶开发的重要方向。【目的】淀粉酶在食品加工、布料退浆、酿酒制造、养殖等领域都有广泛的应用,但目前生产用的淀粉酶来源单一,在溶液中的稳定性较差,需要扩大淀粉酶来源,增强酶的稳定性,使其进一步适应复杂多变的工业生产环境。【方法】利用选择培养基在三门峡黄河湿地表层土样中筛选得到20株具有淀粉酶活性的菌株,采用杯碟法检测粗酶液的活性并对其中活性最高的3株菌进行鉴定,对其中酶活性最高的菌株运用紫外照射的方式进行诱变并测定致死率,选择突变后酶活最高的菌株,优化培养条件,并测定突变后淀粉酶的活性和作用条件范围。利用3,5-二硝基水杨酸（3,5-dinitrosalicylic acid,DNS）法测定诱变前后酶活并进行活性对比。【结果】在三门峡黄河湿地表层土壤中筛选得到3株淀粉酶活性较高的菌株并编号S03、S08和S17。根据16S rRNA基因序列比对、革兰氏染色形态观察结合生理生化分析显示,菌株S03、S08和S17分别为Aeromonas、Exiguobacterium和Bacillus,其淀粉酶最适NaCl浓度是10%-12%,最适...     

龙凤湿地与珰奈湿地底泥细菌古菌多样性及其对环境因子的响应

【背景】城市湿地和天然湿地受到人为扰动影响的程度显著不同。【目的】研究2种不同类型湿地底泥微生物多样性及种类的差异。【方法】采集冬夏两季城市湿地(龙凤湿地)和天然湿地(珰奈湿地)的底泥样品,使用16S rRNA基因测序技术测定底泥中细菌和古菌群落结构,分析2种湿地底泥的细菌、古菌差异及环境因素与微生物的相关性。【结果】龙凤湿地底泥中的硫杆菌属(Thiobacillus)、芽孢杆菌属(Bacillus)和鞘氨醇单胞菌属(Sphingomonas)丰度显著高于珰奈湿地(P<0.05);Methanoregula在珰奈湿地底泥中的丰度高于龙凤湿地;冬季厌氧绳菌属(Anaerolinea)和甲烷八叠球菌属(Methanosarcina)在珰奈湿地底泥中的丰度显著高于龙凤湿地(P<0.05)。【结论】龙凤湿地与珰奈湿地的差异主要影响湿地底泥中参与元素循环的细菌和产甲烷古菌的丰度,人为干扰和低温会降低湿地中微生物的多样性,pH、盐分和碱性磷酸酶是显著影响微生物多样性的环境因素。     

Dissimilatory microbial sulfur and methane metabolism in the water column of a shallow meromictic lake

Lake Harutori is a brackish meromictic lake with a steep physicochemical gradient in shallow water. Anoxic water below the chemocline has been characterized by high concentrations of sulfide (>10 mM) and methane (>1.5 mM). Previously, we reported that uncultured bacteria in the SEEP-SRB1 group were major sulfate reducers in the lake [21], but knowledge of sulfur oxidation and methane metabolism was scarce. In this current study, the Lake Harutori microbial community structure in the mixolimnion (at depths of 1.5 m and 3.0 m), upper chemocline (3.5 m), and monimolimnion (4.5 m) was further investigated by 16S rRNA gene amplicon sequencing and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). Reads of type I and II methanotrophs were retrieved mainly from 3.5 m and above. Methanotrophic bacteria detected by CARD-FISH accounted for 3.1% of DAPI-stained cells at 3.5 m. Detection frequencies of reads affiliated with the genera Sulfurimonas and Thiomicrorhabdus, which are known to comprise sulfur oxidizers, were relatively high at 3.5 m. Methanogenic archaeal reads were retrieved from the monimolimnion and they affiliated with the genus Methanosaeta. CARD-FISH counts indicated that the cells of Methanosaeta/Methanosarcina/Methanomicrobiales accounted for up to 0.8% of the DAPI-stained cells in the monimolimnion. On the other hand, many of the reads retrieved primarily from the monimolimnion were affiliated with phylogenetically novel uncultured groups.