Wetland Landscape Research Articles

Landscape effects on mallard habitat selection at multiple spatial scales during the non-breeding period

Previous studies that evaluated effects of landscape-scale habitat heterogeneity on migratory waterbird distributions were spatially limited and temporally restricted to one major life-history phase. However, effects of landscape-scale habitat heterogeneity on long-distance migratory waterbirds can be studied across the annual cycle using new technologies, including global positioning system satellite transmitters. We used Bayesian discrete choice models to examine the influence of local habitats and landscape composition on habitat selection by a generalist dabbling duck, the mallard (Anas platyrhynchos), in the midcontinent of North America during the non-breeding period. Using a previously published empirical movement metric, we separated the non-breeding period into three seasons, including autumn migration, winter, and spring migration. We defined spatial scales based on movement patterns such that movements >0.25 and 30.00 km were classified as relocation scale. Habitat selection at the local scale was generally influenced by local and landscape-level variables across all seasons. Variables in top models at the local scale included proximities to cropland, emergent wetland, open water, and woody wetland. Similarly, variables associated with area of cropland, emergent wetland, open water, and woody wetland were also included at the local scale. At the relocation scale, mallards selected resource units based on more generalized variables, including proximity to wetlands and total wetland area. Our results emphasize the role of landscape composition in waterbird habitat selection and provide further support for local wetland landscapes to be considered functional units of waterbird conservation and management.

Comparison of Qinzhou bay wetland landscape information extraction by three methods

Abstract. Wetland ecosystem plays an important role on the environment and sustainable socio-economic development. Based on the TM images in 2010 with a pretreament of Tasseled Cap transformation, three different methods are used to extract the Qinzhou Bay coastal wetlands using Supervised Classification (SC), Decision Trees (DT) and Object -oriented (OO) methods. Firstly coastal wetlands are picked out by artificial visual interpretation as discriminant standard. The result shows that when the same evaluation template used, the accuracy and Kappa coefficient of SC, DT and OO are 92.00 %, 0.8952; 89.00 %, 0.8582; 91.00 %, 0.8848 respectively. The total area of coastal wetland is 218.3 km2 by artificial visual interpretation, and the extracted wetland area of SC, DT and OO is 219 km2, 193.70 km2, 217.40 km2 respectively. The result indicates that SC is in the f irst place, followed by OO approach, and the third DT method when used to extract Qingzhou Bay coastal wetland.

Analysis of wetland change in the Songhua River Basin from 1995 to 2008

Wetlands in the Songhua River Basin in both 1995 and 2008 were mapped from land use/land cover maps generated from Landsat Thematic Mapper imagery. These maps were then divided into two categories, i.e. artificial wetland and natural wetland. From 1995 to 2008, the total area of wetland in the Songhua River Basin increased from 93 072.3 km2 to 99 179.6 km2 a net increase of 6107.3 km2. The area of natural wetland decreased by 4043.7 km2 while the area of artificial wetland increased by 10 166.2 km2. Swamp wetland and paddy field wetland became the dominant wetlands and the swamp wetland in the east of the Heilong River system and the north of the Wusuli River system disappeared, being transformed into paddy field wetland. The diversity of wetland landscape is worsening and the distribution of wetland landscape is becoming more unbalanced; the fragmentation of natural wetland has intensified whereas the patch connectivity of artificial wetland has increased. Changes in natural wetlands were primarily caused by climate and socio-economic changes, while changes in artificial wetland were mainly caused by the growth of population and gross domestic product.

Interactions of local climatic, biotic and hydrogeochemical processes facilitate phosphorus dynamics along an Everglades forest-marsh gradient

Abstract. Ecosystem nutrient cycling is often complex because nutrient dynamics within and between systems are mediated by the interaction of biological and geochemical conditions operating at different temporal and spatial scales. Vegetated patches in semiarid and wetland landscapes have been shown to exemplify some of these patterns and processes. We investigated biological and geochemical factors suggested to contribute to phosphorus (P) movement and availability along a forest-marsh gradient in an Everglades tree island. Our study illustrated processes that are consistent with the chemohydrodynamic nutrient (CHNT) hypothesis and the trigger-transfer, pulse-reserve (TTPR) model developed for semiarid systems. Comparison with the TTPR model was constructive as it elaborated several significant patterns and processes of the tree island ecosystem including: (1) concentration of the limiting resource (P) in the source patch (High Head which constitutes the reserve) compared with the resource-poor landscape, (2) soil zone calcite precipitation requiring strong seasonality for evapotranspiration to promote conditions for secondary soil development and calcium phosphate reprecipitation, (3) rewetting of previously dry soils by early wet season precipitation events, and (4) antecedent conditions of the source patch, including landscape position that modulated the effect of the precipitation trigger. Thus, our study showed how water availability drives soil water P dynamics and, potentially, stability of mineral soil P in this tree island ecosystem. In landscapes with extensive water management, these processes can be asynchronous with the seasonality of hydrologic dynamics, tipping the balance between a sink and source of a limiting nutrient.

The Spatial-Temporal Change Pattern of Wetland in the Middle-Lower Yangtze River: A Case Study of Wuhu, Anhui

Wetlands play a number of roles in the environment, which are also considered the most biologically diverse of all ecosystems. Utilizing RS and the GIS software, remote datum were matched and classified. By these transactions, the temporal and spatial changes of wetland landscape are explored in Wuhu, combining qualitative analysis and quantitative methods. This paper analyzed the time-spatial revolution process which indicated that, firstly the area of wetland reduced rapidly from remote sensing image in 1988, 2001 and 2005, secondly the exterior of urban changed acutely and the interior were protected well in view of spatial pattern. Moreover, driving force factors were pointed out. Human activities, especially urbanization were the main causes of wetlands degradation. Simultaneity, the development of farming, the construction of infrastructure and nature were important factors. Owing to rapid economic development and urban sprawling, wetlands are encountering threaten to be converting to other land uses. Thus, the paper provides policy advices for wetland conservation and urban planning toward sustainable development.

Climate forcing of wetland landscape connectivity in the Great Plains

Habitat connectivity is a landscape attribute critical to the long‐term viability of many wildlife species, including migratory birds. Climate change has the potential to affect habitat connectivity within and across the three main wetland complexes in the Great Plains of North America: the prairie potholes of the northern plains, the Rainwater Basin of Nebraska, and the playas of the southern plains. Here, we use these wetlands as model systems in a graph‐theory‐based approach to establish links between climatic drivers and habitat connectivity for wildlife in current and projected wetland landscapes and to discern how that capacity can vary as a function of climatic forcing. We also provide a case study of macrosystems ecology to examine how the patterns and processes that determine habitat connectivity fluctuate across landscapes, regions, and continents.

English

Wetland ecosystem is known as the “kidney” of earth and the “gene pool” of species. It has the functions of regulating climate, flood storage and degradation of pollution. In this paper, based on GIS technology and landscape ecology, wetland changes and its driving forces in the Poyang Lake Eco-economic Zone of China are analyzed. The analysis of landscape pattern demonstrates that there is an increase in the degree of fragmentation of wetlands in the study area. At the same time, the overall aggregation degree of the lake is in the rise. The increased Perimeter-area fractal dimension indicates that the shape of wetland becomes more and more rules. The main driving forces of wetland changes in the Poyang Lake Eco-economic Zone include natural factors and human activities. This study also indicates the main natural factor is the changes of precipitation, though for now, there is increase of average temperature. At the moment, the rapid population growth, regional economic development and other human activities are also the key driving forces of wetland landscape changes in the Poyang Lake Eco-economic Zone. Key words: Wetland change, landscape pattern, climate change, ecosystem management, Poyang Lake.

Monitoring and analyzing wetland landscape pattern change and ecological security using remote sensing images：A case study of Jiangsu coastal wetland

Based on landscape ecology,remote sensing and geographical information system,the authors analyzed the dynamic change of landscape pattern of Jiangsu costal wetland from 1992 to 2009. Combining the remote sensing derived information with Pressure- State- Response model,the authors also assessed AHP and Delphi methods,regional ecological security states and change trends. The experimental results show that the size of natural landscape has been reduced,while the manmade landscape tends to increase,accompanied by a transfer from wetland natural landscape to human landscape. The fragmentation degree has been intensified gradually,and the average fractal dimension tends to decrease,as a result of human intervention. The increased Shannon diversity metrics indicates more richness of wetland landscape types,which has resulted from the transfer of natural landscape to manmade landscape. The results also indicate that the wetland ecological system has been in critical security state,and the percentage of ill and insecure areas has been on the increase,so more attention should be paid to the landscape pattern improvement and ecological building.

基于遥感的湿地景观格局季相分析

基于遥感的湿地景观格局季相分析

Methane emissions from five wetland plant communities with different hydroperiods in the Big Cypress Swamp region of Florida Everglades

The majority of the methane (CH4) emitted from wetlands comes from tropical and subtropical zones. On a global scale, the variability of these emissions had been attributed to water table variations; however, at landscape scales this variability is poorly understood. We measured CH4 fluxes from five characteristic wetland plant communities of southwest Florida representing a gradient in inundation periods. From wettest to driest conditions, communities were designated as deep slough, bald cypress, wet prairie, pond cypress and hydric pine flatwood. Non-steady-state rigid chambers were deployed at each community sequentially at three different times of the day during a 24-month period. CH4 fluxes did not show a discernible daily pattern, in contrast to a marked seasonal increase in emissions during inundation. All wetland communities acted as temporary sinks of CH4, but overall were net sources. Median and mean±standard error fluxes in CH4-Cm−2d−1 were higher in deep slough (11 and 55.3±21.5), followed by the wet prairie (9.01 and 53.3±26.6), bald cypress (3.31 and 5.54±2.51) and pond cypress (1.49, 4.55±3.35). The pine flatwood community acted as a net sink during the study period (0.0 and −1.22±0.81). Seasonality in CH4 emissions was positively correlated with water levels, but not with soil temperature. However, longer inundation periods did not necessarily result in higher CH4 emissions. These findings add to our current knowledge of CH4 fluxes from subtropical wetland ecosystems and have implications for modeling at ecosystem scales in heterogeneous wetland landscapes.

Analysis of water stable isotopes fingerprinting to inform conservation management: Lake Urema Wetland System, Mozambique

The present study focusses on the analysis of water stable isotopes to contribute to understanding the hydrology of the Lake Urema wetland system in central Mozambique towards conservation management.Lake Urema Wetland is located in the Gorongosa National Park at the southernmost extent of the East African Rift System and is situated entirely within the Urema catchment. Of particular concern to the park’s management is the understanding of hydrological processes as these may trigger transformations of ecosystems, habitat losses and wildlife migrations. Concerns over the Lake Urema wetland’s drying up and the trapping of sediments in the floodplain have been raised for some time by conservationists.Water samples were collected for stable water isotope analyses during the wet and the dry seasons for the period 2006–2010 from springs, boreholes, rivers, and Lake Urema. In addition monthly composite precipitation was collected at two rain gauges.The results show that Lake Urema is maintained throughout the dry season merely from water generated during the wet season. It receives water from wet season precipitation and the runoff generated from this precipitation. The water source areas of the lake are the Gorongosa Mountain and the Barue Basement geomorphological units. Consequently, the source of the sediments which have been trapped into the lake and the floodplain has to be identified in these two catchment areas and urgent action is required to rescue the lake. This water body constitutes a groundwater buffer system which supports a unique wetland landscape. The annual inundations’ processes leading to the recharge-drainage cycle in the floodplain are most sensitive to the deposition of sediments, changing hydraulic gradients, and reducing wet season inflows and increasing drainage rates.

습지 방문객의 생태의식과 이용욕구 연구

본 연구는 습지 방문객의 효과적인 관리를 위해 그들의 생태의식과 욕구구조의 연관성 규명을 목적으로 시작하였다. 이를 위해 '습지방문객의 생태의식과 이용욕구수준의 파악', '방문객의 인구통계학적 특성이 생태의식에 미치는 효과', '생태의식과 이용욕구와의 연관성 규명'을 연구문제로 설정하였다. 실증분석은 우포늪 방문객 대상의 설문조사로 진행하였다. 방문객의 생태의식은 던랩(Dunlap)의 15개 NEP 척도로 측정하였고, 이용욕구는 매슬로우(Maslow)의 7단계 욕구를 활용했다. 우포늪에서 3일간 조사한 끝에 총 228부의 설문지를 확보하여 본 분석에 사용하였다. 연구 결과, 방문객들의 생태의식과 이용욕구는 보통 이상의 높은 수준이었다. 생태의식에서는 생태위기 가능성과 반인간주의에 대한 반응이 높았다. 이용욕구에서는 심미적 욕구가 가장 높았고, 그 다음은 인지적 욕구였다. 자아실현욕구와 자존의 욕구는 가장 낮았는데, 이 둘을 제외하면 대체로 욕구 위계가 높을수록 높은 반응을 보였다. 생태의식과 이용욕구는 상관성 분석 결과, 부(-)적 상관과 정(+)적 상관이 섞여 있었으나, 정적 상관의 비율이 3배 이상 높았다. 상관계수도 정적 상관계수가 더 높게 나타나, 생태의식과 이용욕구는 낮은 수준의 정적 상관관계 중심으로 형성되어 있다고 볼 수 있다. 방문객의 생태의식에 따라 상중하의 3개 집단으로 분류하여 이용욕구를 비교 분석한 결과는 생태의식이 높을수록 이용 욕구도 높게 나타났다. 연구 결과, 습지 방문객의 생태의식은 보통 이상의 높은 수준인데, 향후 지속적인 증가가 예상되었다. 따라서 이용욕구 또한 계속 높아질 것이며, 특히 심미적 욕구와 인지적 욕구가 커질 것으로 예상된다. 따라서, 습지의 시각적 자원을 활용한 경관관리가 중요함을 알 수 있다. 아울러 방문객의 지적 욕구를 채워줄 수 있는 컨텐츠가 지속적으로 제공되어야 할 것으로 판단된다. The purpose of this study was to determine the correlation between wetland visitors' consciousness of ecology and their needs and thereby, provide for some effective measures to manage them. For this purpose, 3 study points were set up: "wetland visitors' consciousness of ecology and their needs", "differences of such consciousness depending on their demographic variables" and the "relationship between such consciousness and their needs". To this end, Upo Wetland visitors were surveyed for an empirical analysis. The visitors' awareness about ecology was measured with Dunlap's 15-item NEP Inventory, while their needs were analyzed in reference to Maslow's 7-Step Human Desire Ladder. The survey was conducted at Upo Wetland for 3 days, and as a result, a total of 228 questionnaires were returned. The results of this study can be summarized as follows; First, the visitors' consciousness of ecology and their needs were higher than the normal level. In terms of their consciousness of ecology, their awareness of the ecological crisis potential and anti-humanism was highest. In terms of their needs, the aesthetic need was highest, followed by the cognitive one. On the other hand, the needs for self-achievement and self-esteem were lowest; except them, the higher the needs were positioned at Maslow's ladder of desire, and subjects were more responsive to them. As a result of analyzing the correlation between the subjects' consciousness of ecology and their needs, it was found that the correlation was negative in some sub-areas, while being positive in other sub-areas. After all, the ratio of the sub-areas having a positive correlation was as 3 times high as that of the sub-areas having a negative correlation. Even as for the correlation coefficient values, they were higher in the positive sub-areas, which suggests that the correlation between wetland visitors' consciousness of ecology and their needs were positive, although at a lower level, in overall terms. As a result of comparatively analyzing visitors' needs by dividing them into 3 sub-groups depending on the levels of their consciousness of ecology, it was found that the higher their consciousness of ecology was, their needs were higher. Overall, wetland visitors' awareness of ecology was higher than the normal level, and it was estimated that such awareness would continue to increase. Hence, it could be inferred that their needs, particularly, their aesthetic and cognitive ones would continue to increase, too. Accordingly, it is deemed important to manage the wetland landscape making use of its visual resources, while continuing to provide the visitors with the contents fulfilling their need for knowledge.

The importance of geology, climate and anthropogenic disturbances in shaping boreal wetland and aquatic landscape types

Boreal wetlands are recognized as important wildlife habitats, especially as breeding and staging grounds for a large number of waterfowl. The main objectives of this study were to quantify the distribution of wetland and aquatic wildlife-habitat landscape types within boreal Quebec and to determine how such recognizable wildlife habitats vary among climatic regimes and landforms. A total of 456 forest maps systematically distributed within a 540 000 km2 area were used to classify 12 wetland and 5 different aquatic habitat types. Habitat types belonging to wetland and aquatic classes respectively covered 10.3 % and 11.7 % of the study area. Spatial heterogeneity was confirmed using a hierarchical cluster analysis by identification of 6 wetland landscape types further categorized into 3 groups: wet, dry, and anthropogenic. The last emphasizes the magnitude of human alteration of aquatic habitats, with reservoirs representing 26% of total water coverage. Partial redundancy analyses showed that landform data alone had better explanatory power (28%) than climatic data (19%) to account for the variation in wetland coverage. These results suggest that terrestrial ecozones based on landform (rather than climate) could serve as indicators for wetland conservation planning and facilitate wetland conservation and management decisions.

The Expression of Genius Loci in Urban Wetland Planning and Design

As the important component of urban environment, urban wetland is always intimately related with the development of the city and peoples lives. However, along with the more attention to the zoology recover and reconstruction of urban wetland, the wetland plannings become common with others, and lack of the expression of Genius Loci. Therefore, its pressed for setting up wetland landscape combined with zoology and humanism in city area. The article puts forward the methods of expression of Genius Loci by means of reasonable wetland planning, various and abundant wetland space forms, taking full advantage of natural environment elements and so on.

Role of permeability barriers in alluvial hydromorphic palaeosols: The Eocene Pondaung Formation, Myanmar

AbstractThis study examines the lateral distribution of hydromorphy in the fine‐grained alluvial deposits of the Eocene Pondaung Formation, central Myanmar. Through detailed outcrop analysis and using a combined sedimentological and pedological approach, this study proposes a reconstruction of Pondaung overbank floodplain palaeoenvironments. The variations of hydromorphic features in the different overbank sub‐environments are then discussed and used to build a model of hydromorphic variability in alluvial deposits. Two main architectural associations with distinctive lithofacies and pedogenic features were identified, corresponding to different sub‐environments: heterolithic deposits and extensive mudstone successions. The heterolithic deposits display variegated fine‐grained lithofacies and contain poorly developed palaeosols with gley and vertic features, which are interpreted to reflect a seasonal wetlands landscape, developed in actively aggrading avulsion belts. Extensive mudstone successions with Vertisols that locally exhibit mukkara‐style pseudogley features are interpreted to represent a distal open‐forested environment. The palaeosols of both sub‐environments display dense local hydromorphic variations they are also characterized by a gradual shift from gley‐dominated to pseudogley‐dominated features with increasing distance from the avulsion belt. The clay‐dominated lithology of the floodplain parent material, which forms numerous subsurface permeability barriers, is shown to have acted as a fundamental control in limiting water‐table dynamics in coarse‐grained parts of the succession, thereby favouring hydromorphic variability. Palaeosol sequences of the Pondaung Formation contrast with the soil‐landscape associations described in other studies and provide an alternative model with which to account for the hydromorphic variability in poorly drained, alluvial soils. The model proposed as an outcome of this study demonstrates that hydromorphic variations can be dramatic in floodplains where permeability barriers are numerous. Further, the model stresses the importance of undertaking detailed lateral palaeosol analyses prior to making interpretations regarding hydromorphic variability.

Spatiotemporal variation in the microclimatic edge effect between wetland and farmland

The creation of wetland edges associated with anthropogenic fragmentation is common in wetland landscapes and brings about a unique microclimatic change that affects adjacent farmland. However, microclimatic edge effects within this kind of landscape are not well quantified. Thus, using a study site located in the northeastern Sanjiang National Nature Reserve, China, we investigated the spatiotemporal variations in the microclimatic variables of the surface layer across the wetland‐farmland edge. Air temperature and relative humidity data were collected continuously along a horizontal transect at four different heights over different periods, and the relative humidity was converted to specific humidity. Sigmoid models were used to fit the horizontal gradients of microclimatic edge effects. Then, based on the parameters in the fitted models, the characteristics of the edge effects were quantified with two indices, the magnitude of edge effect (MEE) and the spatial range of edge effect (REE). Under a light wind condition, the microclimatic features across the edge generally presented sigmoid ecological gradients in the horizontal direction, with unique spatial and temporal patterns: (1) In a normal year, wetland patches cooled and moistened the adjacent farmlands during the daytime and had a warming‐moistening effect during the nighttime. (2) Vertically, the absolute MEE value of the microclimatic variables decreased, but the REE increased with increasing height. (3) The MEE and REE for air temperature and specific humidity varied with the time of day, both shifting at dawn and dusk when the gradients were absent. (4) At the interannual scale, when compared to the farmland, the wetland was cooler at night in a dry year but warmer in a normal year. The detection of spatiotemporal microclimatic patterns in the wetland‐farmland edge zone may enable further understanding of how wetland degradation affects adjacent farmland ecology under human disturbance and promote better management and restoration of fragmented wetlands.

The Influence of Hydrologic Restoration on Groundwater-Surface Water Interactions in a Karst Wetland, the Everglades (FL, USA)

Efforts to rehydrate and restore surface water flow in karst wetlands can have unintended consequences, as these highly conductive and heterogeneous aquifers create a close connection between groundwater and surface water. Recently, hydrologic restoration efforts in the karstic Taylor Slough portion of the Everglades has changed from point source delivery of canal water (direct restoration),to the useofa series of surface water recharge retention basins (diffuse restoration). To determine the influence of restoration on groundwater- surface water interactions in the Taylor Slough headwaters, a water budget was constructed for 1997-2011 using 70 hydro- meteorological stations. With diffuse restoration, groundwater seepage from the Everglades toward the urban boundary in- creased, while the downstream delivery of surface water to the main portion of the slough declined. The combined influence of diffuse restoration and climate led to increased intra-annual variability in the volume of groundwater and surface water in storage but supported a more seasonally hydrated wetland compared to the earlier direct tactics.The data further indicated that hydrologic engineering in karst wetland landscapes en- hances groundwater-surface water interactions, even those designed for restoration purposes.

Impact on Vegetation due to Deep Drain in Water Valley of South Australia

Drains have been widely used to treat dry land salinity and removing excessive water from wetland area. The main aim of this study is to evaluate the impact on vegetation by deep and open drains. Aerial images of two different time interval were evaluated by using dot grid overlaid method. Deep and open drain had significantly changed the vegetation composition of study area. Proportional coverage of bare ground had increased by 132.9%. Conversely, the proportional coverage of lakes, shrubs and grassland had decreased by 26.1., 21.1 and 3.9%, respectively. The impact was severe in the wetland landscape in comparison to the pasture landscape.DOI: http://dx.doi.org/10.3126/on.v11i1.8244 Our Nature Vol.11(1) 2013: 54-60

Study on Wetland Landscape Pattern Change in the Ximen Island Marine Special Protected Area based on RS and GIS

Study on Wetland Landscape Pattern Change in the Ximen Island Marine Special Protected Area based on RS and GIS

Spatial-temporal analysis of wetland landscape pattern under the influence of artificial dykes in the Yellow River delta

he influence of anthropogenic activities, especially artificial dykes, on the coastal wetland landscape is now considered as a serious problem to the coastal ecosystem. It is important and necessary to analyze changes of coastal landscape pattern under the influence of artificial dykes for the protection and management of coastal wetland. Our study aimed to reveal the quantitative characteristics of the coastal wetland landscape and its spatial-temporal dynamics under the influence of artificial dykes in the Yellow River delta (YRD). It was analyzed by the methods of the statistical analysis of landscape structure, five selected landscape indices and the changes of spatial centroids of three typical wetland types, including reed marshes, tidal flats and aquaculture-salt fields. The results showed that: (1) Reduction of wetland area, especially the degradation of natural wetlands, had been the principal problem since the dykes were constructed in the YRD. The dykes created conditions for the development of artificial wetlands. However, the new born artificial wetlands were still less than the vanished natural wetlands. (2) Compared with the open area, the building of artificial dykes significantly speeded up the changes of landscape patterns and the aggravation of the landscape fragmentation in the closed area. (3) The changes of area-weighted centroids of three typical wetland landscapes were greatly affected by dykes, and the movement of the centroid of the aquaculture-salt field was very sensitive to the dykes constructed in the corresponding period.