Integrated simulation of runoff and groundwater in forest wetland watersheds

A Distributed Forest Wetland Hydrologic Model （DFWHM） was constructed and used to examine water dynamics in the different climates of three different watersheds （a cold region, a sub-tropic region, and a large-scale watershed）. A phenological index was used to represent the seasonal and species changes of the tree canopy while processes of snow packing, soil freezing, and snow and ice thawing were also included in the simulation. In the cold region, the simulated fall of the groundwater level in winter due to soil f^eezing and rise in spring due to snow and ice melting compare well with the observed data. Because the evapotranspiration and interaction of surface water and groundwater are included in the model, the modeled seasonal trend of the groundwater level in the sub-tropic region is in agreement with observations. The comparison between modeled and observed hydrographs indicates that the simulations in the large-scale watershed managed to capture the water dynamics in unsaturated and saturatedzones.

Forest Wetland Area and the Forest Sector Economy in the U.S. South

This article reviews current data on forest wetlands and their economic contributions in the South, ranging from Texas to Virginia. Based on USDA Forest Service Forest Inventory and Analysis (FIA) data, the wetland category comprised 17.7% of timber land area on all private and public lands in the South. This included 4.25 million ha of hydric sites;0.77 million ha mesic wet;9.55 million ha mesic, with only seasonal access;for a total of 14.57 million ha. The Natural Resource Inventory (NRI) for 2012 on private lands estimated that there were 14.71 million ha forested wetlands, which comprised 17.7% of all forested private forest area. The 2015 National Land Cover Data for the South estimated that there were 17.8 million ha of woody wetlands, which comprised 8% to 12% of the southern land area, and there were also 4.45 million ha of emergent herbaceous sites. About 10% of the southern timber forest sector would be based on harvests from wetland forests economy ($455 million per year), while the 17.7% of wetland land area would provide a proportional share of the annual nontimber forest products ($44 million) and payments for ecosystem services ($134 million). Wetlands also provide important nontimber forest products, and ecosystem services, which are beginning to develop active private and public markets.

Ecosystem carbon storage and sink/source of temperate forested wetlands in Xiaoxing’anling, northeast China

Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tree layer. Our results demonstrate that these forested wetlands were generally carbon sinks in the Xiaoxing’anling, and there was obvious spatial variation in carbon storage of ecosystems along the moisture gradient.

Maintenance of an abrupt boundary between needle-leaved and broad-leaved forests in a wetland near coast

There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnusjaponica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, Japan. To clarify maintenance mechanisms, we studied the forest profile, water level, groundwater and precipitation chemistry, seedling establishment patterns in relation to microhabitats, and seed migration. The profile of groundwater level insufficiently explained the abrupt boundary formation, while the groundwater chemistry differed significantly between the two forests ; i.e., EC, Na^＋, K^＋, Mg^2＋, Ca^2＋ and Cl^- were higher in P. glehnii forest and pH was lower. Precipitation in P. glehnii forest contained richer Na＋, Ca^2＋ and Cl^-, indicating that the differences in surface-water chemistry were mostly derived from precipitation. Solar radiation was less than 2.2 MJ.m^-2.d^-1 on P. glehnii forest in late June, while that was patchily distributed in A.japonica forest with a range from 1.0 to 3.7 MJ＇m^-2＇d^-1. Moss cover on the soil surface, most of which were made of Sphagnum spp., was 60% in P. glehnii forest, but was 10% in A. japonica forest. Surface water chemistry represented by pH was considered to determine the development of Sphagnum moss. About 70% of P. glehnii seedlings 〈 1.3 m in height established on moss cover. Seed-sowing experiments suggested that seed germination and seedling survival for both species were significantly higher in P. glehnii forest. Therefore, the regeneration of P. glehnii in A. japonica forest was negligible, owing to the paucity of favorable microhabitats and low seedling establishment. A. japonica regenerated only by resprouting, and the seedlings were few in both forests. In addition, A. japonica seed migration into the P. glehnii forests was greatly restricted, and low solar radiation in the P. glehnii forest contributed to low seedling survival. Based on those results, we concluded that Picea glehnii and Alnusjaponica could develop distinct and selfish environments being unsuitable for the other species and inhibit natural afforestation of another species each other by excluding invasion.

Metabolic diversity and seasonal variation of soil microbial communities in natural forested wetlands

This study explores the effects of vegetation and season on soil microorganisms and enzymatic activity of different wetlands in a temperate climate.Microbial carbon metabolism diversity was assessed using community-level physiological profiles(CLPP)with 31 different carbon substrates.CLPP indicated that significant interactions occur during carbon substrate metabolism of the microorganisms.Furthermore,the different types of vegetation present in the wetland ecosystem combined with the seasonal effects to influence microbial carbon metabolism and enzymatic activity.The most significant differences occurred to carbohydrates,carboxylic acids,and amino acids.The Mantel test confirmed positive correlations between soil enzymatic activities and microbial carbon metabolism.Soil microorganisms in Betula ovalifolia and Carex schmidtii wetlands used carbon substrates more efficiently in summer than those in other forested wetlands during other periods.Enzymatic activities also showed a similar trend as microbial carbon metabolism.The results demonstrate that microbial carbon metabolism patterns can be used as biological indicators in wetland ecological alterations due to vegetation type or to seasonal factors.

Maintenance of an abrupt boundary between needle-leaved and broad-leaved forests in a wetland near coast

There is an abrupt boundary between two well-developed wetland forests, a stand consisting of a broad-leaved, nitrogen-fixer Alnus japonica and a stand of the needle-leaved Picea glehnii Masters, in eastern Hokkaido, Japan.To clarify maintenance mechanisms, we studied the forest profile, water level, groundwater and precipitation chemistry, seedling establishment patterns in relation to microhabitats, and seed migration.The profile of groundwater level insufficiently explained the abrupt boundary formation, while the groundwater che-mistry differed significantly between the two forests;i.e., EC, Na+, K+, Mg2+, Ca2+ and Cl-were higher in P.glehnii forest and pH was lower.Precipitation in P.glehnii forest contained richer Na+, Ca2+ and Cl-, indicating that the differences in surface-water chemistry were mostly derived from precipitation.Solar radiation was less than 2.2 MJ·m-2·d-1 on P.glehnii forest in late June, while that was patchily distributed in A.japonica forest with a range from 1.0 to 3.7 MJ·m-2·d-1.Moss cover on the soil surface, most of which were made of Sphagnum spp., was 60% in P.glehnii forest, but was 10% in A.japonica forest.Surface water chemistry represented by pH was considered to determine the development of Sphagnum moss.About 70% of P.glehnii seedlings < 1.3 m in height established on moss cover.Seed-sowing experiments suggested that seed germination and seedling survival for both species were significantly higher in P.glehnii forest.Therefore, the regeneration of P.glehnii in A.japonica forest was negligible, owing to the paucity of favorable microhabitats and low seedling establishment.A.japonica regenerated only by resprouting, and the seedlings were few in both forests.In addition, A.japonica seed migration into the P.glehnii forests was greatly restricted, and low solar radiation in the P.glehnii forest contributed to low seedling survival.Based on those results, we concluded that Picea glehnii and Alnus japonica could develop distinct and selfish environments being unsuitable for the other species and inhibit natural afforestation of another species each other by excluding invasion.

Forest composition and red oak (Quercus sp.) response to elevation gradients across greentree reservoirs

Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.

多源多特征集成的南水北调工程丹江库区湿地时空格局演变

丹江口水库是中国南水北调工程的关键水源区。随着城镇化发展以及大坝二次建设,库区湿地生态系统变化显著,亟需湿地生态科学监测。以丹江库区为例,依托Google Earth Engine(GEE)平台,首先采用已有土地覆盖数据集生成湿地样本集,其次整合Landsat影像、DEM等数据构建多源特征集合,并基于Jeffries-Matusita(JM)距离进行特征优选,使用随机森林(RF)算法实现了1985~2023年丹江库区湿地制图。结果表明:①本文提出的样本采集流程可有效提高样本质量,为长时序分类样本采集提供参考;②湿地分类特征优选后特征数由37个减为27个,分类总体精度变化不大,优选后的特征应用于丹江库区湿地分类的平均总体精度(OA)以及平均数量和分配分歧指数(QADI)分别为89.53%和0.0802,说明特征优选有效减少信息冗余,提高影像分类效率;③1985~2023年,丹江库区湿地面积呈波动增加趋势,从1985年的17839.85 ha扩大到2023年的28872.48 ha,面积增长38.12%。总体来说,丹江库区湿地生态系统呈现出逐步恢复和优化的良好态势。

东北地区森林草原湿地生态系统外来入侵物种概况及对策

在对东北地区部分有害生物来源考证的基础上,筛选出56种外来入侵物种作为东北地区森林、草原、湿地生态系统的主要种类,并对其入侵特征进行分析。结果表明:原产地以北美洲种类最多,入侵东北种类总体呈不断增加势头,入侵途径以无意引入为主,入侵地以辽宁省种类居多,入侵生境在森林、草原、湿地生态系统均有代表性种类。进一步筛选出18种外来入侵物种作为东北地区森林、草原、湿地生态系统的重要种类,并对其重要性进行评述,根据每种在入侵过程的阶段性,分别提出防止入侵、阻止扩散和抑制危害的防控管理对策。针对完善入侵生物学理论提出3点建议,针对提升东北地区外来入侵物种防控能力提出4点建议。

多源遥感数据与机器学习算法的沼泽湿地信息提取

基于多源遥感数据与机器学习算法,旨在探讨提高沼泽湿地信息提取精度的方法。利用GEE(Google Earth Engine)平台获取的Sentinel-1合成孔径雷达(SAR)数据、Sentinel-2多光谱数据以及地形数据,结合多种机器学习算法提取沼泽湿地遥感信息,并在大兴安岭山区的南瓮河自然保护区以及松嫩平原区的莫莫格保护区进行精度验证。结果表明:利用多源遥感数据结合机器学习算法的研究方法,可显著提高沼泽湿地信息提取精度。在平原地区沼泽湿地信息提取中,雷达数据比多光谱数据贡献度更高;在山地地区沼泽湿地信息提取中,二者具有相近的贡献度。Sentinel-1、Sentinel-2数据和地形湿度指数数据的组合更有利于各种地形沼泽湿地信息提取。随机森林机器学习算法对沼泽湿地信息提取精度最高。

基于GEE和Sentinel-2影像的杭州城市湿地精细化分类研究

基于Google Earth Engine(GEE)云平台,使用Sentinel-2卫星影像数据,采用随机森林算法面向杭州城市湿地类型进行遥感分类研究.研究结果表明:在进行湿地类型精细化分类时,相比于使用单一特征信息分类,多特征信息的组合可以显著提高分类精度,最优特征组合包括传统光谱特征、红边光谱特征、变换特征、纹理特征和地形特征,其总体精度为81.2%,Kappa系数为0.75;不同特征信息对于不同湿地类型的提取具有重要作用,传统光谱特征对于滩地和养殖池的识别非常有利,而红边光谱特征和变换特征分别对草本沼泽和湖泊的识别更为有效.此外,红边光谱特征和纹理特征的组合有利于运河/水渠的识别.通过特征对比实验可为湿地精细化分类的案例研究提供参考,湿地分类结果可为杭州城市湿地信息的遥感识别提供数据支撑.

造景:当代景观建筑设计方法探析——以北京南苑森林湿地公园体育驿站为例

北京南苑森林湿地公园地点位于南苑,南苑是北京皇家苑囿起源地,京郊唯一平原湿地型皇家御园,清中期大运河水源补充地,具有独特的湿地基底和历史景观资源。该文研究对象为当代景观建筑,以北京南苑森林湿地公园体育驿站项目实践为例,探索以造景为目标导向的当代景观建筑设计方法。方案结合体育驿站场地环境和园区景观建筑整体设计定位,确立景观形象营造目标,即以自然湿地基底为依托,营造出与生态环境高度融合的体育驿站景观建筑,与场地使用者共同构成人在城市山林中运动健身的活跃景象。通过自然渗透的场地规划布局、轻介入的建筑构型以及公共性场所营造的造景原则,在满足体育驿站功能需求的基础上,通过场地规划、建筑构型以及场所营造的造景方法,达到目标造景效果,以期为当代景观建筑设计提供可行性思路。

扬州市森林、湿地生态系统外来入侵植物调查分析与管理对策

通过线路踏查、资料分析,对扬州市森林、湿地生态系统外来入侵植物的种类组成、生活型、繁殖方式、原产地、入侵方式、生态系统类型及分布进行了研究。结果表明:扬州市外来入侵植物共有18种,隶属于9科15属,其中菊科种类最多(9种),占比50.00%;调查到的外来入侵植物均为草本植物,以一二年生草本植物最多(10种),占比55.56%;这些草本植物大多均依靠种子繁殖,仅有空心莲子草、大薸和凤眼蓝3种水生草本植物依靠营养繁殖;按原产地统计来看,原产于美洲的植物种类最多(15种),占83.33%;有50.00%(9种)入侵植物属于有意引入,44.44%(8种)属于无意引入,自然传入的仅有豚草1种。按生态系统来看,乔木林地和灌木林地中的外来入侵植物种类最多,有15和13种。就扬州市外来入侵植物发生情况进行了讨论分析,并提出相应的管理对策。

基于特征优选的GF-6WFV影像湿地信息提取

以洪泽湖湿地为研究对象,构建一种基于特征优选的湿地面向对象分类方法,利用高分六号宽幅多光谱(GF-6 WFV)影像进行湿地信息提取。首先对GF-6 WFV数据进行预处理和多尺度分割;然后提取光谱、植被指数、水体指数、红边指数和纹理特征,利用基于平均准确度下降法(mean decrease accuracy,MDA)的递归排除算法生成最优特征集;最后,基于最优特征集进行湿地分类,通过对比4种特征优选算法发现基于MDA的递归排除算法能更有效地进行特征变量选择,使用6种方案开展湿地分类实验。结果表明GF-6 WFV影像的红边波段和红边指数在湿地分类中具有重要作用,利用优选特征集的分类精度最高,为87.43%,比未进行特征优选的分类精度提高了1.55%。研究成果将为GF-6 WFV影像在湿地监测方面提供技术参考。

2019-2022年天津北大港湿地遥感分类数据集

湿地是地球上最重要的生态系统之一,具有净化水质、维持生物多样性等重要功能。由于湿地具有特殊的水文和植被特征,传统的监测方法难以对其进行测绘和管理。随着大数据和云计算的兴起,GEE(Google Earth Engine)为长时间序列的数据处理提供了可能。本研究基于GEE平台,结合Sentinel-1雷达影像和Sentinel-2光学影像,利用随机森林分类算法对天津北大港湿地进行信息提取,探讨多源遥感数据和时间序列特征对天津北大港湿地分类的重要性,并最终得到2019–2022年天津北大港湿地遥感分类数据集。经实测数据验证,分类结果的总体精度为95.35%,符合精度要求。本数据集可为天津北大港湿地保护和管理提供科学依据。

伊春林区森林和湿地资产与生态系统服务价值评估研究

为量化评估伊春市森林资源保护与发展所取得的成就,深刻诠释绿水青山就是金山银山理念,采用国际主流的森林环境经济核算方法,以2020年评估基准年份,对伊春林区森林与湿地资源的资产及其生态系统服务价值进行评估,并对未来森林与湿地资源资产及其生态系统服务价值的变化进行量化预测。从研究结果来看,伊春林区森林与湿地资源的资产及其生态系统服务价值巨大,该结果对于展示生态建设成果和践行“绿水青山就是金山银山”理念、推动绿色转型发展具有重要参考价值。

昆山森林公园改造提升之专类花园营建策略研究

昆山市区向西不远,在城湖之间的一片绿色的斑块就是昆山市城市生态森林公园。由于时代的变迁、城市的更新扩容,公园的景观价值和使用功能越来越无法满足游客日益增长的需求,于是改造提升势在必行。本次改造在保留利用的基础上,加入了科普教育、游憩体验等功能,使城市生态绿色资源得到有效的共享。植被改造通过针灸式梳理、微创式改造,营造了一个以专类花园为载体,具有时代风貌,城市与自然互动,绿色共享的城市活力新公园。

陆良县森林、草原、湿地生态系统外来入侵物种现状及防控对策

笔者通过实地调查和分析,掌握了目前入侵陆良森林、草原、湿地生态系统的9种外来入侵物种,阐述了紫茎泽兰、喜旱莲子草、垂序商陆等8种陆生植物以及1种昆虫红火蚁等外来入侵物种的发生、分布、危害治理现状,提出了加强宣传及监测预警、分类综合防治等管理建议,为今后森林、草原、湿地生态系统外来入侵物种防控管理工作提供参考。

2022年广西林草湿地图斑监测底图处理方法

森林、草原、湿地图斑监测底图的完善是2022年森林、草原、湿地图斑监测工作的基础和前提。针对国家下发的监测底图存在的共性问题和广西地方管理的需要,提出监测底图处理思路和手段。根据广西2022年林草湿图斑监测工作操作细则要求,基于ArcEngine二次开发技术开发辅助处理插件,实现不同调查单位监测底图统一处理。

基于特征优选和时空融合算法的黄河三角洲湿地类别制图方法研究

滨海湿地的遥感分类研究对于滨海湿地的保护和规划具有重要意义。为此,以黄河三角洲作为研究区,采用2019年3—10月获取的8景Landsat8 OIL作为数据源,使用GEE(Google Earth Engine)云平台,根据影像的不同特征构建了7种不同的分类方案;然后,使用随机森林分类器对不同特征集合进行分类,并选择其中分类效果最好的用于绘制黄河三角洲地区的湿地类别图。其中8,9月份数据由于受到云的污染导致质量差,使用增强型自适应反射率时空融合模型(enhanced spatial and temporal adaptive reflectance fusion model,ESTARFM)算法对有云区域进行填补处理。结果表明:①ESTARFM时空融合模型生成的预测影像与真实影像波段表现出较好的相关性,其R值均能达到0.73以上,说明重构的影像可以用于本研究;②使用随机森林算法对研究区地物类型进行分类,其中方案7通过特征优选,分类结果总体精度达92.28%,Kappa系数达0.91,分类结果与湿地实况相吻合,比常规方案分类精度更高。研究结果有助于了解和掌握该区域湿地不同类型的空间分布特征,可为区域生态环境的保护和规划提供科学依据。