Swin Transformer for Complex Coastal Wetland Classification Using the Integration of Sentinel-1 and Sentinel-2 Imagery

The emergence of deep learning techniques has revolutionized the use of machine learning algorithms to classify complicated environments, notably in remote sensing. Convolutional Neural Networks (CNNs) have shown considerable promise in classifying challenging high-dimensional remote sensing data, particularly in the classification of wetlands. State-of-the-art Natural Language Processing (NLP) algorithms, on the other hand, are transformers. Despite the fact that transformers have been utilized for a few remote sensing applications, they have not been compared to other well-known CNN networks in complex wetland classification. As such, for the classification of complex coastal wetlands in the study area of Saint John city, located in New Brunswick, Canada, we modified and employed the Swin Transformer algorithm. Moreover, the developed transformer classifier results were compared with two well-known deep CNNs of AlexNet and VGG-16. In terms of average accuracy, the proposed Swin Transformer algorithm outperformed the AlexNet and VGG-16 techniques by 14.3% and 44.28%, respectively. The proposed Swin Transformer classifier obtained F-1 scores of 0.65, 0.71, 0.73, 0.78, 0.82, 0.84, and 0.84 for the recognition of coastal marsh, shrub, bog, fen, aquatic bed, forested wetland, and freshwater marsh, respectively. The results achieved in this study suggest the high capability of transformers over very deep CNN networks for the classification of complex landscapes in remote sensing.

Phenology is the dominant control of methane emissions in a tropical non-forested wetland

Tropical wetlands are a significant source of atmospheric methane (CH4), but their importance to the global CH4 budget is uncertain due to a paucity of direct observations. Net wetland emissions result from complex interactions and co-variation between microbial production and oxidation in the soil, and transport to the atmosphere. Here we show that phenology is the overarching control of net CH4 emissions to the atmosphere from a permanent, vegetated tropical swamp in the Okavango Delta, Botswana, and we find that vegetative processes modulate net CH4 emissions at sub-daily to inter-annual timescales. Without considering the role played by papyrus on regulating the efflux of CH4 to the atmosphere, the annual budget for the entire Okavango Delta, would be under- or over-estimated by a factor of two. Our measurements demonstrate the importance of including vegetative processes such as phenological cycles into wetlands emission budgets of CH4.

Initial dispersal behavior and survival of non-native juvenile Burmese pythons (Python bivittatus) in South Florida

Background Dispersal behavior is a critical component of invasive species dynamics, impacting both spatial spread and population density. In South Florida, Burmese pythons (Python bivittatus) are an invasive species that disrupt ecosystems and have the potential to expand their range northward. Control of python populations is limited by a lack of information on movement behavior and vital rates, especially within the younger age classes. We radio-tracked 28 Burmese pythons from hatching until natural mortality for approximately 3 years. Pythons were chosen from 4 clutches deposited by adult females in 4 different habitats: forested wetland, urban interface, upland pine, and agricultural interface. Results Known-fate survival estimate was 35.7% (95% CI = 18% - 53%) in the first 6 months, and only 2 snakes survived 3 years post hatching. Snakes moving through ‘natural’ habitats had higher survival than snakes dispersing through ‘modified’ habitats in the first 6- months post-hatching. Predation was the most common source of mortality. Snakes from the agricultural interface utilized canals and displayed the largest net movements. Conclusions Our results suggest that pythons may have lower survival if clutches are deposited in or near urbanized areas. Alternatively, juvenile pythons could quickly disperse to new locations by utilizing canals that facilitate linear movement. This study provides critical information about behavioral and life history characteristics of juvenile Burmese pythons that will inform management practices.

Eco-hydrology interactions between trees, soil and water in terrestrial and wetland areas: The effect of tree planting on water flow dynamics in Wairarapa Wetlands, New Zealand

<p>During the last two decades there has been increasing interest in the role of forests and wetlands as flood mitigating tools due to growing concerns regarding the sustainability of many traditional engineering flood defences such as dykes, sea walls and dams. In forests, the role is facilitated by the interaction between trees, soil and water. Specifically trees reduce surface runoff and prevent flooding through increased evapotranspiration and canopy interception and enhance physical and hydraulic properties of soil that are critical for the absorption and retention of flood waters by the soil. It is increasingly realised that the answer to flood mitigation is not a blanket recommendation to “plant trees”. This is because the role of trees varies spatially and temporally as a function of climate, topography, rainfall properties, soil type and condition, catchment scale and geology, among others. For example, where trees are present in wetlands, particularly forested wetlands, the mechanisms by which trees interact with soil and water are similar to that in forests but because of a high water table, the impact of trees may be reduced. Therefore, the mere presence of forests and forested wetlands will not necessarily deliver flood risk management. The purpose of this study was to explore the effectiveness of trees as flood mitigating tools under various bio-geo climatic factors in forests and forested wetland environments. Three forms of investigation were followed to fulfil this purpose. A detailed literature review was carried out to assess the role of trees and forests as flood mitigation tools under changing climate, topography, species type, rainfall properties, soil type and condition, catchment scale and geology. A field experiment was carried out to collect data and analyse the effect of trees on soil physical and hydraulic properties that include bulk density, saturated hydraulic conductivity, soil organic carbon, soil moisture content, matric potential and soil moisture retention in a previously forested wetland undergoing restoration in New Zealand. A spatially explicit decision support tool, the Land Use Capability Indicator (LUCI) was then used to determine appropriate areas where intervention can be targeted to optimise the role of trees as flood mitigating tools in previously forested wetlands undergoing restoration. The detailed review identified a major data gap in the role of trees under hydric conditions (high water table), along with uncertainties on their effectiveness in large catchments (>˜40 km²) and in extreme rainfall events. The field experiment provided the first set of soil hydrology data from an ephemeral wetland in New Zealand showing the benefits of newly established trees in improving hydraulic conductivity of soils. The soil hydrology data is a useful baseline for continuous monitoring of the forested wetlands undergoing restoration. The use of the Land Use Capability Indicator was its first application for the optimisation of flood mitigation in a forested wetland. Its suggested target areas are not necessarily conducive for survival of some tree species, although if suitable species are established, flood risk mitigation could be maximised. Further research on what native species are best for what conditions and in what combinations is recommended, to increase survival in the proposed target areas.</p>

Eco-hydrology interactions between trees, soil and water in terrestrial and wetland areas: The effect of tree planting on water flow dynamics in Wairarapa Wetlands, New Zealand

<p>During the last two decades there has been increasing interest in the role of forests and wetlands as flood mitigating tools due to growing concerns regarding the sustainability of many traditional engineering flood defences such as dykes, sea walls and dams. In forests, the role is facilitated by the interaction between trees, soil and water. Specifically trees reduce surface runoff and prevent flooding through increased evapotranspiration and canopy interception and enhance physical and hydraulic properties of soil that are critical for the absorption and retention of flood waters by the soil. It is increasingly realised that the answer to flood mitigation is not a blanket recommendation to “plant trees”. This is because the role of trees varies spatially and temporally as a function of climate, topography, rainfall properties, soil type and condition, catchment scale and geology, among others. For example, where trees are present in wetlands, particularly forested wetlands, the mechanisms by which trees interact with soil and water are similar to that in forests but because of a high water table, the impact of trees may be reduced. Therefore, the mere presence of forests and forested wetlands will not necessarily deliver flood risk management. The purpose of this study was to explore the effectiveness of trees as flood mitigating tools under various bio-geo climatic factors in forests and forested wetland environments. Three forms of investigation were followed to fulfil this purpose. A detailed literature review was carried out to assess the role of trees and forests as flood mitigation tools under changing climate, topography, species type, rainfall properties, soil type and condition, catchment scale and geology. A field experiment was carried out to collect data and analyse the effect of trees on soil physical and hydraulic properties that include bulk density, saturated hydraulic conductivity, soil organic carbon, soil moisture content, matric potential and soil moisture retention in a previously forested wetland undergoing restoration in New Zealand. A spatially explicit decision support tool, the Land Use Capability Indicator (LUCI) was then used to determine appropriate areas where intervention can be targeted to optimise the role of trees as flood mitigating tools in previously forested wetlands undergoing restoration. The detailed review identified a major data gap in the role of trees under hydric conditions (high water table), along with uncertainties on their effectiveness in large catchments (>˜40 km²) and in extreme rainfall events. The field experiment provided the first set of soil hydrology data from an ephemeral wetland in New Zealand showing the benefits of newly established trees in improving hydraulic conductivity of soils. The soil hydrology data is a useful baseline for continuous monitoring of the forested wetlands undergoing restoration. The use of the Land Use Capability Indicator was its first application for the optimisation of flood mitigation in a forested wetland. Its suggested target areas are not necessarily conducive for survival of some tree species, although if suitable species are established, flood risk mitigation could be maximised. Further research on what native species are best for what conditions and in what combinations is recommended, to increase survival in the proposed target areas.</p>

Floodplain Geomorphology and Response to Hurricanes: Lower Pee Dee Basin, South Carolina

Undeveloped forested wetlands in the valleys of coastal plain rivers can play a large role in storing floodwater and attenuating river flooding. In the lower Pee Dee, Little Pee Dee, and Lynches Rivers, these wetlands played a large role in mitigating downstream flooding following Hurricane Florence. Wetland forest flood mitigation was most effective for large flows in the Great Pee Dee River, where flooding on former river terraces determined the course of overbank flow and the potential storage of floodwaters. Floodwater storage and attenuation of water level were less effective if larger flows were limited to the Little Pee Dee River. Large rains prior to Hurricane Matthew, and to a lesser extent Tropical Storm Bertha, caused the forested wetland to be a source of additional flow, although with little increase in peak stage.