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1.
东北三江平原湿地动态变化研究 总被引：9，自引：0，他引：9
借助遥感、GIS手段,以1989年TM、2001年ETM和2007年CBERS遥感影像为主要数据源,通过分析三江平原湿地的分布现状、时空变化规律,并用动态度和景观格局指数量化变化,研究其近20年的变化情况。结果显示:三江平原湿地现主要分布在同江、抚远、富锦、虎林等县市;湖泊和河流湿地呈稳定趋势,沼泽湿地大面积减少,在研究时段内共减少5 356.69 km2,人工湿地大幅度增加,共增加11 597.68 km2。天然湿地破碎化程度加剧,人工湿地呈连片化趋势,受人类活动的影响较大。 相似文献
2.
三江平原湿地时空演变探究 总被引：1，自引：0，他引：1
借助遥感、GIS技术,利用1975年MSS、2000年TM和2015年ETM数据,采用人工目视解译方法,辅助野外调查验证,得到三江平原湿地空间分布数据,进而研究1975年至2015年三江平原湿地的分布特征,并结合研究区气温和降水量数据对湿地变化的影响因素进行分析。研究结果表明:2000年以前,湿地减少的面积为8 426.81 km~2,其中沼泽草甸湿地减少最为明显,人工湿地增加了6 939.87 km~2。2000年以后,沼泽湿地变化依然剧烈,面积减少了2 794.24 km~2。自然湿地破碎化程度加剧,人工湿地面积增加,受人类活动影响较大。 相似文献
3.
近30年吉林市景观格局变化及气候效应 总被引：2，自引：0，他引：2
在ArcGIS、ENVI、Excel和FRAGSTATS软件支持下, 利用景观指数中的斑块数量、最大斑块指数、斑块密度、周长面积分维数、聚集度和香农多样性指数, 对1980年、1995年和2010年的吉林市景观格局进行了分析。结果表明:近30年间吉林市斑块数量、斑块密度、周长面积分维数和香农多样性指数呈先增加后减少的趋势, 聚集度呈先减少后增加的趋势, 最大斑块指数逐渐减少;林地景观面积、草地景观面积一直在减少, 湿地景观面积呈先增加后减少趋势, 旱田景观面积逐渐增加。在东北地区气候变化背景下, 吉林市景观格局的变化对该区气候产生了一定的影响, 使该区气温上升、降雨量减少。吉林市景观格局变化与气温、降雨量变化的空间分布格局有较好的对应关系。 相似文献
4.
吉林省西部属于生态脆弱区,湿地作为重要的生态单元,其发展变化对区域生态环境产生重要影响。近年来,由于受到较多的人为干扰,该区域湿地变化极为显著。为了充分发挥湿地生态环境功能,促进区域生态环境改善,以吉林省西部2000-2010年湿地变化数据为基础,基于情景分析法设置了自然变化（情景1）、规划优先（情景2）和生态优先（情景3）三种情景,利用CLUE-S模型对2020年湿地空间格局进行模拟,并从湿地空间分布变化特征和景观抗干扰能力两个方面对不同情景下的湿地格局进行分析评价,旨在了解不同情景下湿地格局的差异性,寻求合理的湿地空间分布格局。结果表明：CLUE-S模型的土地利用预测正确率为84.54%,κ指数为0.83,能够较好地模拟2020年湿地格局变化,特别是对沼泽湿地、水域和建设用地模拟效果较好;不同情景下湿地空间格局特征具有明显的差异性,三种情景下的沼泽湿地的质心均偏向西南,水域的质心均偏向东南,而水田的质心在情景1中偏向东北,在情景2和情景3中偏南,沼泽湿地和水田在情景3比情景1中具有更强的聚集性,而水域恰相反,情景1比情景3中具有更强的聚集性;不同情景下的湿地景观抗干扰能力不同,2010-2020年,情景1中的所有湿地类型的景观干扰指数都逐渐增加,而情景2和情景3中沼泽湿地和水域的景观干扰指数逐渐降低,尤以生态优先情景的下降幅度最大。表明在实施科学的生态建设时,湿地景观具有较强的抗干扰能力。 相似文献
5.
利用MSS、ETM+、CBERS-2、BJ-2、02C和TH1多时相卫星遥感数据,分别提取1975年、2000年、2007年和2016年皖江经济带湿地现状及变化的遥感信息,研究皖江经济带湿地遥感现状及变化规律。结果表明:皖江经济带湿地类型主要为河流湿地、湖泊湿地、沼泽湿地和人工湿地,市县级地域湿地分布不均、类型不全;1975—2016年,人工湿地面积增加,增长率为55.32%;沼泽湿地面积减少,减少率为69.97%;湖泊湿地和河流湿地面积较稳定,增长率分别为1.80%和2.06%。湿地变化分两个阶段:第一阶段(1975—2007年),湿地面积总体增加,河流湿地、湖泊湿地和沼泽湿地面积减少,人工湿地面积增加;第二阶段(2007—2016年),湿地面积总体增加,但河流湿地和湖泊湿地面积增加,沼泽湿地面积继续减少,人工湿地面积继续增加,湿地面积增减受人类活动影响较大。 相似文献
6.
扎龙湿地属于典型的芦苇沼泽湿地,由于扎龙湿地水环境的变化,扎龙湿地土地利用类型的变化为:耕地、居民地、盐碱地总体上略呈增加趋势,草地呈减少趋势,湖泊和水库、明水沼泽、芦苇沼泽等湿地面积变化与来水量的丰枯变化相关,明水沼泽和芦苇沼泽的变化趋势呈反相关.土地利用类型对湿地面积的影响程度最大的是居民地面积,其次是耕地、盐碱地、草地面积的变化. 相似文献
7.
采用新疆喀什噶尔河流域1990、2000和2010年的Landsat-TM影像数据和中巴资源卫星数据, 结合GIS技术, 分析了喀什噶尔河流域近20 a土地利用/覆被及景观格局动态变化特征, 并对其变化原因进行探讨. 结果显示: 在1990-2010年喀什噶尔河流域耕地、建设用地、盐碱地、水域湿地、裸土地和其他未利用地面积呈不断增加趋势, 变化幅度分别为73.92%、51.44%、24.27%、10.24%、6.47%和2.98%; 林地、草地和沙地面积减少, 变化幅度分别为-4.13%、-17.16%和-0.73%; 裸石岩砾面积近20 a基本维持不变. 利用转移矩阵可知, 流域新增耕地面积主要来自于16.46%的草地和3.36%的林地; 新增建设用地主要来自于1.46%的耕地和0.22%的草地; 新增水域湿地面积主要来自于0.18%的草地; 新增盐碱地面积主要来自于0.28%的草地. 1990-2010年的20 a里喀什噶尔河流域耕地和水域湿地分布趋于集中, 景观优势度增强, 且斑块之间的联系不断增强. 林地和草地面积减少, 景观趋于破碎化, 景观优势度降低. 喀什噶尔河流域土地利用类型及景观指数的变化受人口、经济、政策和技术的多重影响, 导致流域耕地面积增加、植被退化. 因此, 合理利用流域水土资源对流域生态环境安全十分重要. 相似文献
8.
茂兰喀斯特自然保护区撂荒地时空演变、机制及其植被恢复 总被引：5，自引：3，他引：2
本研究以高分辨率遥感影像和实地调查为基本数据源,运用Arcmap和Fragstats软件,研究了茂兰自然保护区弃耕撂荒地的空间分布与动态演变。结果表明:整个保护区的弃耕地主要集中在缓冲区和实验区;从2005年到2015年,弃耕地的空间分布范围明显减少,斑块面积逐渐增加;2005年和2010年,撂荒地数量与距聚落距离呈正相关,2015年,撂荒地主要分布在距聚落<200 m、600~800 m和>1 000 m的缓冲范围;弃耕地植被恢复型演替主要分布在核心区和缓冲区。研究结果为全面反映保护区的人地关系演变和生态恢复情况提供了参考。 相似文献
9.
《地下水》2021,(4)
为揭示近40 a来无定河湿地保护区气候变化规律,本文采用气候倾向率、Mann-Kendall检验和滑动t检验法,研究了1981-2019年无定河湿地保护区气温、降水量、相对湿度和风速的变化趋势。结果表明:近40 a无定河湿地保护区气候呈现“暖湿化”趋势,总体呈现气温上升、降水增加和湿度增大的趋势。气温发生突变上升于1996和2012年,年际变化较大,容易出现温度异常;降水量发生突变于2010年;相对湿度发生突变减小于1994年,突变增大的年份较多。气温、降水量与风速在年内呈单峰型分布;雨热同期现象明显,夏季7、8月降水多以暴雨的形式出现;日照时数与相对湿度的年内变化趋势相反。该研究成果为无定河湿地保护区水资源管理和生态环境治理提供科学依据。 相似文献
10.
利用空间自相关模型,结合GIS技术,对别拉洪河流域不同尺度上湿地空间自相关的动态变化进行了研究。结果表明,自20世纪50年代至2000年,别拉洪河流域湿地面积逐渐减少,湿地全局空间自相关呈先增加后减小再增加的"N"字型趋势;别拉洪河流域湿地高-高自相关类型有逐渐减少并向流域下游扩张的趋势,而低-低自相关类型有逐渐增加并向流域上游扩张的趋势;湿地空间自相关表现出明显的尺度效应,随着研究尺度的增大湿地空间自相关性逐渐增强;别拉洪河流域湿地空间自相关的动态变化主要是由人类对湿地的开发造成的。 相似文献
11.
对松嫩平原中南部黑土区20世纪80年代以及目前土壤中氮含量数据资料分析结果显示,近40年来研究区土壤氮的流失率达到5.02%.总体上呈现出土壤氮含量丰富-较丰富的一级、二级土地面积大量减少,而土壤中氮含量中等-缺乏的三级、四级和五级土地面积逐渐增大.对研究区不同土地利用方式土壤氮含量变化特征统计结果显示,研究区人为活动影响较强的水田和旱田两种主要土地利用方式土壤中氮含量丰富区的土地所占面积比例分别减少了20.9和6.1个百分点;人为活动影响相对较弱的沼泽湿地、草地和林地3种土地利用方式土壤氮含量丰富区的面积有所增加.对不同行政区市县土壤氮含量变化特征空间分析结果表明,研究区有6个市县土壤氮流失达到重度程度,建议作为黑土氮流失治理的重点地区;有8个市县（区）土壤氮流失达到中度程度,应作为土壤氮流失防与治兼顾的重点地区. 相似文献
12.
The Sanjiang Plain has the most representative and largest concentration of inland freshwater wetlands in China, most of which have been degraded or have disappeared as a result of agricultural development and climatic change since the 1950s. To better understand the spatial and temporal variation and driving forces of marsh reduction, this study investigated variations of marsh reduction in the Honghe region of the Sanjiang Plain, Northeast China over a 30-year period, and analyzed the role of the different driving forces separately and their combined effect on marsh reduction and identified what driving forces have played key roles on the reduction in different periods. Nine natural and anthropogenic variables from remote sensing, GIS data and field surveys, such as precipitation, temperature, precipitation anomaly, population density, agricultural population density, per capita GDP, distance to road, distance to canal and distance to settlement, were evaluated on their impact on observed variations of marsh reduction between 1975 and 2006. The results show that all of these driving forces have significant influences on the decline of the marsh area, and the combination of driving forces that has crucial impacts on marsh reduction varied largely from 1975 to 2006. During 1975–1989, it was the construction of canal and road networks in farms and changes in average annual precipitation that led to marsh reduction. After 1989, the reduction was mainly related to increases in agricultural population, per capita GDP and settlements. These findings may help understand the declines or degradation of marsh areas and provide an empirical and theoretical base for managers, who design and implement wetland management and planning. 相似文献
13.
A 115-year-old railroad levee bisecting a tidal freshwater marsh perpendicular to the Patuxent River (Maryland) channel has created a northern, upstream marsh and a southern, downstream marsh. The main purpose of this study was to determine how this levee may affect the ability of the marsh system to gain elevation and to determine the levee’s impact on the marsh’s long-term sustainability to local relative sea level rise (RSLR). Previously unpublished data from 1989 to 1992 showed that suspended solids and short-term sediment deposition were greater in the south marsh compared to the north marsh; wetland surface elevation change data (1999 to 2009) showed significantly higher elevation gain in the south marsh compared to the north (6?±?2 vs. 0?±?2 mm year?1, respectively). However, marsh surface accretion (2007 to 2009) showed no significant differences between north and south marshes (23?±?8 and 26?±?7 mm year?1, respectively), and showed that shallow subsidence was an important process in both marshes. A strong seasonal effect was evident for both accretion and elevation change, with significant gains during the growing season and elevation loss during the non-growing season. Sediment transport, deposition and accretion decreased along the intertidal gradient, although no clear patterns in elevation change were recorded. Given the range in local RSLR rates in the Chesapeake Bay (2.9 to 5.8 mm year?1), only the south marsh is keeping pace with sea level at the present time. Although one would expect the north marsh to benefit from high accretion of abundant riverine sediments, these results suggest that long-term elevation gain is a more nuanced process involving more than riverine sediments. Overall, other factors such as infrequent episodic coastal events may be important in allowing the south marsh to keep pace with sea level rise. Finally, caution should be exercised when using data sets spanning only a couple of years to estimate wetland sustainability as they may not be representative of long-term cumulative effects. Two years of data do not seem to be enough to establish long-term elevation change rates at Jug Bay, but instead a decadal time frame is more appropriate. 相似文献
14.
In Louisiana, salt marshes are being created in an effort to offset the large loss of such habitat that has occurred over the last 50 yr. Primary productivity is an important function and indicator of success for salt marsh creation and restoration projects. The aim of this study was to determine whether the aboveground and belowground productivity of the dominant salt marsh grassSpartina alterniflora in created marshes in southwest Louisiana began to approximate productivity levels in natural marshes, over time. Net annual aboveground primary productivity (NAPP) was measured by a harvest technique, while the ingrowth core method was used to estimate net annual belowground primary productivity (NBPP). NAPP levels were similar to those found in other, Louisiana salt marshes, while NBPP levels were similar to or higher than the reported range forS. alterniflora studied along the Atlantic and Gulf of Mexico coasts. NAPP tended to decrease as the created marshes aged, but the levels in the oldest, 19 year old, created marsh were still well above values measured in the, natural marshes. It was estimated that it would take 35 yr after marsh creation for NAPP in the created marshes to become equivalent to that in natural marshes. NBPP in the created marshes became equivalent to levels found in the natural marshes after 6–8 yr, but then belowground production increased with marsh age, reaching an asymptote that surpassed natural marsh levels. Equivalency in primary productivity has not been reached in these marshes. Elevation also affected productivity, as higher elevational sites with greater topographic heterogeneity had significantly lower aboveground and belowground biomass levels than those with elevations closer to mean sea level. This underscores the need to construct marshes so that their mean elevation and degree of topographic heterogeneity are similar to natural marshes. 相似文献
15.
Contrasting Decadal-Scale Changes in Elevation and Vegetation in Two Long Island Sound Salt Marshes 总被引：1，自引：0，他引：1
Northeastern US salt marshes face multiple co-stressors, including accelerating rates of relative sea level rise (RSLR), elevated nutrient inputs, and low sediment supplies. In order to evaluate how marsh surface elevations respond to such factors, we used surface elevation tables (SETs) and surface elevation pins to measure changes in marsh surface elevation in two eastern Long Island Sound salt marshes, Barn Island and Mamacoke marshes. We compare marsh elevation change at these two systems with recent rates of RSLR and find evidence of differences between the two sites; Barn Island is maintaining its historic rate of elevation gain (2.3?±?0.24 mm year?1 from 2003 to 2013) and is no longer keeping pace with RSLR, while Mamacoke shows evidence of a recent increase in rates (4.2?±?0.52 mm year?1 from 1994 to 2014) to maintain its elevation relative to sea level. In addition to data on short-term elevation responses at these marshes, both sites have unusually long and detailed data on historic vegetation species composition extending back more than half a century. Over this study period, vegetation patterns track elevation change relative to sea levels, with the Barn Island plant community shifting towards those plants that are found at lower elevations and the Mamacoke vegetation patterns showing little change in plant composition. We hypothesize that the apparent contrasting trend in marsh elevation at the sites is due to differences in sediment availability, salinity, and elevation capital. Together, these two systems provide critical insight into the relationships between marsh elevation, high marsh plant community, and changing hydroperiods. Our results highlight that not all marshes in Southern New England may be responding to accelerated rates of RSLR in the same manner. 相似文献
16.
We compared the functions and values of fringing salt marshes to those of meadow marshes along the southern Maine/New Hampshire
coast. Differences included soil organic matter content, plant species richness, and percent cover of high and low-marsh species.
More sediment was trapped per unit area in fringing marshes than in meadow marshes, but this difference was not significant.
Similarities included aboveground and belowground peak season biomass and the ability to dampen wave energy. Both marsh types
reduced the height of waves coming onto the marsh surface by 63% only 7 m into the marsh. Fringing marshes are diverse in
terms of their physical characteristics (width, length, slope, elevation, soils). Despite their small size, they are valuable
components of estuaries, performing many ecological functions to the same degree as nearby meadow marshes. More effort should
be made to include them in regional efforts to conserve and restore coastal habitats. 相似文献
17.
Field experiments were completed to determine patterns of evapotranspirative water loss from salt and tidal freshwater marshes in Virginia. Water losses from “Mariotte systems” attached to open-water lysimeters and lysimeters vegetated by dominant marsh macrophytes were used to calculate hourly rates of open-water evaporation (Eo) and evapotranspiration (ET), respectively, during low tide. In the tidal freshwater marsh, ET was significantly greater than Eo (p=0.002, n=6); in the salt marsh, there were no differences between mean rates of ET and Eo (p=0.200, n=3). The ratio ET:Eo was highly correlated with leaf area index (LAI) (r2=0.82). In the tidal freshwater marsh, the amount of water loss due to plant transpiration was partitioned from total evapotranspiration by covering the water surface of the lysimeters with styrofoam beads. Measured transpiration rates in the tidal freshwater marsh were strongly correlated with leaf area index according to the following linear regression equation: T=0.355(LAI)?0.084 (r2=0.797, n=10). Because LAI was shown to be a good predictor of the relative increase in ET over Eo, it is likely that in vegetated tidal freshwater marshes with high leaf densities most atmospheric water loss comes from plants, not from the surface of the marsh. In salt marshes, low plant densities do not contribute substantially to atmospheric water loss, suggesting that paths of water transport and patterns of solute concentration in the subsurface environment are different compard to the tidal freshwater marsh. 相似文献
18.
基于涡度相关技术对三江平原典型沼泽湿地的水热通量进行了连续观测,研究沼泽湿地能量平衡和蒸散发的季节变化,确定观测期内沼泽湿地总蒸散量,并通过逐步回归方程估算沼泽湿地水面蒸发和植被蒸腾。结果表明,沼泽湿地的能量平衡具有明显的季节变化特征,总体看来,潜热通量是湿地的主要能量支出项,占净辐射的45.5%,感热通量和存储热通量分别占净辐射的27.9%和26.7%。2006年5~10月份沼泽湿地总蒸散量为310.6mm,月均日蒸散量最高值出现在7月。观测期内沼泽湿地水面蒸发量约为221mm,占总蒸散量的71%左右,植被蒸腾量则约占总蒸散量的29%,湿地蒸散发以水面蒸发为主。 相似文献
19.
Elizabeth Burke Watson Cathleen Wigand Earl W. Davey Holly M. Andrews Joseph Bishop Kenneth B. Raposa 《Estuaries and Coasts》2017,40(3):662-681
Tidal salt marsh is a key defense against, yet is especially vulnerable to, the effects of accelerated sea level rise. To determine whether salt marshes in southern New England will be stable given increasing inundation over the coming decades, we examined current loss patterns, inundation-productivity feedbacks, and sustaining processes. A multi-decadal analysis of salt marsh aerial extent using historic imagery and maps revealed that salt marsh vegetation loss is both widespread and accelerating, with vegetation loss rates over the past four decades summing to 17.3 %. Landward retreat of the marsh edge, widening and headward expansion of tidal channel networks, loss of marsh islands, and the development and enlargement of interior depressions found on the marsh platform contributed to vegetation loss. Inundation due to sea level rise is strongly suggested as a primary driver: vegetation loss rates were significantly negatively correlated with marsh elevation (r 2?=?0.96; p?=?0.0038), with marshes situated below mean high water (MHW) experiencing greater declines than marshes sitting well above MHW. Growth experiments with Spartina alterniflora, the Atlantic salt marsh ecosystem dominant, across a range of elevations and inundation regimes further established that greater inundation decreases belowground biomass production of S. alterniflora and, thus, negatively impacts organic matter accumulation. These results suggest that southern New England salt marshes are already experiencing deterioration and fragmentation in response to sea level rise and may not be stable as tidal flooding increases in the future. 相似文献