Water Corridors Research Articles

The Aquatic Metatron: A large‐scale experimental facility to study the combined effects of habitat fragmentation and climate change on aquatic meta‐ecosystems

Abstract Revealing the effects of multiple global change drivers on ecosystem dynamics and functioning is a crucial endeavour, which necessitates the use of appropriate tools. Here, we present the Aquatic Metatron, a unique mesocosm facility providing a large‐scale experimental resource to study the combined effects of global change components, in particular climate change and habitat fragmentation, on the ecological and evolutionary dynamics of aquatic ecosystems. The Aquatic Metatron consists of 144 mesocosms of 2 m3 each that can be connected to each other with aquatic corridors, and—for a subset of them—with aerial corridors. This enables effective control of dispersal across meta‐ecosystems. In addition, the temperature in each mesocosm is supervised and precisely controlled, either through a heating (all mesocosms) or a cooling (72 mesocosms) system. All mesocosms can be monitored automatically for abiotic and biotic factors (pH, dissolved oxygen, conductivity, turbidity and chlorophyll a) allowing for long‐term experimentation. We tested the platform by conducting three experiments involving the manipulation of various components of global change: climate warming, biodiversity loss, eutrophication and aquatic/aerial fragmentation. The technical innovations of the platform have been validated, in particular its capacity to accurately recreate multiple climatic scenarios (e.g. heatwaves, warming, cooling) and the possibility of using aerial and water corridors to simulate fragmented landscapes. The Aquatic Metatron is located in the south‐west of France (https://sete‐moulis‐cnrs.fr/fr) and is part of AnaEE France and AnaEE‐ERIC (https://www.anaee.eu/), which are large‐scale research infrastructures. The Aquatic Metatron is a research facility accessible to external researchers and projects.

Meteorological effects of ventilation corridor in central urban areas: A case study of Wuhan

How ventilation corridors affect urban climate is attracting researchers' attention. Taking the inland Chinese city of Wuhan as an example, this paper first uses remote sensing image technology to evaluate the urban thermal environment. Additionally, based on the GIS/RS spatial analysis method, the ventilation corridors in the central urban area are identified and constructed. Finally, the mesoscale meteorological model WRF-UCM is used to simulate four cases with different corridor forms to explore the impact of different corridors on the climate environment in Wuhan during the summer. The results indicate that: (1) The WRF-UCM model, when coupled with LCZ classification, can significantly improve the accuracy of mesoscale urban canopy meteorological field simulations. (2) The water corridors located in the central urban area can effectively regulate the temperature and wind environment during summer. In the high-temperature period of the day, the average temperature in the central city decreases by 0.3–0.4 °C, the heat island proportion index decreases by 1.61 %, and the strong heat island proportion index decreases by 1.89 % in the afternoon. During the period of low temperature, the average wind speed in the central urban area increased by 0.05 m/s increase, and even increased by 0.1 m/s. (3) The specific humidity value of the green corridor is reduced by 0.0000136 kg/kg in comparison to the construction land in the corridor, while the water corridor can increase by 0.000133 kg/kg. If the two kinds of surface, water and green land, are organically combined in the corridor, it will be able to improve the hot and humid conditions in Wuhan in summer. (4)Low-rise and low-density construction land as the corridors in the central urban area can not improve the urban thermal and wind environment. Through an attempt to conduct a complete workflow of urban heat island analysis, ventilation corridor identification and setting, urban climate simulation, analysis and summary, the authors believe that it is an effective set of working methods in sustainable urban planning, design, and policy-making. The implementation of pertinent research findings in the domain of urban planning and design demonstrates its universal applicability and has the potential to extend to analogous research and practice.

Construction of ecological network in Suzhou based on the PLUS and MSPA models

Building regional ecological network can alleviate the notable contradiction between land use and ecological development in the process of rapid urbanization. Suzhou is the center city of the Yangtze River Delta urban cluster and a typical water network city, but high intensity land use has fragmented its ecological space. The study firstly introduced the patch generation land use simulation (PLUS) model to simulate the land use under the ecological priority scenario in Suzhou in 2032, combining the land use data in 2002, 2012 and 2022 to provide basis for the construction of ecological network in the later stage. Secondly, the ecological sources of the four periods were identified by combining morphological spatial pattern analysis (MSPA) and landscape connectivity analysis, and the ecological corridors and nodes of each period were screened and classified by minimum cumulative resistance (MCR) model, gravity model and hydrological analysis. Then we superimposed the screened sources, corridors, and nodes to construct an ecological network pattern in Suzhou that can develop in harmony with the land use dynamics. Finally, the degree of optimization was verified by the network structural evaluation in comparison with the ecological network in 2022. The results indicate that (1) Suzhou has the largest area of water among the land use types, with good ecological substrate. Under the guidance of the ecological green development strategy, the woodland and grassland areas will slightly increase in 2032. The overall land use pattern will generally remain consistent with that in 2022, and landscape fragmentation will be mitigated. (2) A total of 23 ecological sources are identified, mainly located near Taihu Lake, Yangcheng Lake and Yangtze River. Among them, Taihu Lake is the most important ecological source. 76 ecological corridors are screened, including 31 construction corridors, 22 protected corridors and 23 potential corridors, mostly water corridors. 54 ecological nodes are selected, divided into 21 general strategic points, 12 potential strategic points, 11 restorative strategic points and 10 break points. (3) The plan forms an ecological spatial pattern of “three cores, four pieces, multiple corridors and multiple sources” and proposes corresponding refined management measures to promote sustainable development in the Yangtze River Delta region. In addition, this study aims to propose a framework for ecological network construction coupled with land use simulation, which can provide new ideas for ecological construction of similar regions affected by urbanization around the globe.

Movement of Southern European Aquatic Alien Invertebrate Species to the North and South

Due to globalisation and anthropopressure (intensification of shipping, creation of water corridors connecting seas, cultivation of commercial species), the movement of aquatic species has increased in recent years. The determination of trends in the movement of aquatic species in their geographical distribution over time is important because it may help in the management of a species in aquatic ecosystems. There are also knowledge gaps on the long-term trends in the movements of Southern European aquatic alien invertebrates. The study provides the first evidence of both northward and southward movements of these species based on available observations from 1940 to 2021, using meta-analyses and GAM modelling. To date, the majority (98%) of analysed Southern European aquatic alien invertebrates of Mediterranean and Ponto-Caspian origin have moved to the north. Among them, 61% are Ponto-Caspian aquatic alien invertebrates that moved only to the north, and 4% are Mediterranean aquatic alien invertebrates that moved only to the north; the rest include species that moved to the north and south: 27% are Ponto-Caspian aquatic alien invertebrates, and 6% are Mediterranean aquatic alien invertebrates. The one-way movement to the south was observed only in 2% of Mediterranean aquatic alien species. The study will help in understanding the movement patterns of Southern European aquatic alien invertebrates and in the effective management of aquatic ecosystems that allow for the co-existence of people and the rest of biodiversity.

Construction of Water Corridors for Mitigation of Urban Heat Island Effect

The urban heat island (UHI) effect is becoming increasingly prominent owing to accelerated urbanization in Fuzhou, affecting the lives of people. Water is an important landscape element that can effectively improve the urban thermal environment. The construction of water corridors has been proven to mitigate the intensity of the UHI effect in Fuzhou. Therefore, we obtained the distribution of a water system in Fuzhou from image data and analyzed temperature watersheds using the inversion of surface temperature to investigate the inner mechanism of the water system influencing the UHI effect. The water system was superimposed with hot spots to obtain cooling ecological nodes and construct water corridors to mitigate the UHI effect. The temperature watershed areas in Fuzhou are: Minhou County (353.77 km2), Changle (233.06 km2), Mawei (137.82 km2), Cangshan (71.25 km2), Jin’an (55.99 km2), Gulou (16.93 km2), and Taijiang (15.51 km2) Districts. Hot spots were primarily located in Changle, Cangshan, Jin’an, Gulou, and Taijiang Districts. The superposition of the water system and temperature watershed yielded 152 cooling ecological nodes, which were concentrated in the Minjiang and Wulong River watershed, with no cooling ecological nodes distributed within the central city. Twenty-five cooling ecological nodes were selected in the hot spot areas, which were primarily distributed in reservoirs, inland rivers, and park water systems. We constructed 12 water corridors, including four, three, two, one, one, and one in the Minhou County, Changle, Mawei, Jin’an, Cangshan, and the Gulou and Taijiang Districts.

High-resolution multivariate analysis of the hydrochemical signature of water corridors in the upper Río de la Plata estuary, Argentina

Major world river-estuaries integrate the hydrochemical characteristics of the basin with specific signatures which are maintained until complete mixing or discharge to the sea. The chemical signature of distinct water masses and the anthropogenic impact in the Upper Río de la Plata estuary (RLP) were evaluated by high-resolution continuous monitoring (i.e. every 200 m) of conductivity, turbidity, pH, temperature, chlorophyll a and coloured dissolved organic matter (CDOM), discrete analysis of suspended particulate matter (SPM) grain size composition combined with multivariate analysis (K-means clustering, Principal Component Analysis). The characteristic signatures of main RLP tributaries such as the Paraná River, yielding higher conductivity, CDOM, turbidity and coarser SPM, and the Uruguay River, with clearer, more eutrophic waters enriched in very fine SPM, were maintained 60 km seaward from the estuary head. Across the river, three water corridors with distinct signatures and variable widths (3–20 km) were identified reflecting the transition from Paraná to Uruguay River waters. Multivariate techniques also allowed the identification of a polluted coastal corridor (higher conductivity and CDOM and lower turbidity) impacted by wastewater discharges from the metropolitan Buenos Aires and La Plata cities extending 100 km seaward. The combined strategy of high-resolution monitoring, discrete sampling and multivariate techniques was a useful tool to identify water masses, corridors of flow and anthropogenic sources in a heavily urbanized estuary.

Experimental and numerical investigation of squat submarines hydrodynamic performances

This paper empirically examines the hydrodynamic performances of squat submarines under the resistance and wave tests beside numerical investigation of pressure drag reduction techniques. Despite vast information about the operation of the streamlined fluid vessels, there is not much information about the geometries and hydrodynamic behaviors of squat vessels with L/D ratios below four. This study experimentally investigates the impacts of various relative depths and flow inclinations, intending to find drag, heave, and sway forces at the velocities of 0.5, 1.0, 1.5, 2.0, and 2.5-m/s. A one-tenth scaled model of a squat submarine is examined under the resistance and wave train scenarios as the captive model in the towing tank experiments via 110 unique testing scenarios. Then, different pressure drag reduction techniques on the full-scale submarine are evaluated numerically at one-phase fluid by developing stern geometric optimization, nose rod devices, water corridors, and surface patterns at the bow and stern. Results present drag forces increase up to 150% at the 0.5D level for the resistance and wave tests due to the influences of the free surface water. The drag coefficients at the fully submerged depth of 6D differ by up to 13.3% between the numerical and experimental evaluations.

Water corridors management: a case study from Iraq

ABSTRACT In Iraq, cities are expanding without regard to green infrastructure. Green and agricultural spaces are not being retained but instead are being converted into residential and commercial areas. Along with the changing climate, these changes decrease the quality of life. This study aims to assess knowledge deficiencies and current water management practices in expanding Al-Kut city in Iraq. An integrated, comprehensive vision for the city was formulated based on the green infrastructure concept to take advantage of the rivers’ banks and water corridors in order to mitigate climate change and urban heat island effects. It was concluded that there is mismanagement of water corridors within the city, which is squandering the opportunity to incorporate the abundance of water resources and green infrastructure into the cityscape to enhance the community's quality of life.

Streams Under Urban Pressure: Blue-Green Infrastructure Planning and Design Approaches for Bursa Ayvali Creek Corridor

In order to prevent the adverse effects of rapid urbanization and construction on the urban landscape, the protection and planning of the hydrological network systems with the open green spaces is a contemporary issue for cities. Within the scope of ensuring the sustainability of water resources and green open spaces, it is necessary to protect the natural water corridors for a sustainable environment, to store rainwater, to protect and feed the qualities of groundwater, and to create permeable surfaces. In many developed countries of the world, blue-green infrastructure solutions are produced respecting the natural structure of the water resources with innovative techniques. Ayvali Creek is an important branch of the Nilufer Stream, which is the main stream of the city of Bursa. Along this creek corridor under industrial, agricultural, and urban pressures, water pollution is observed and the natural habitat area is damaged. This study aims to categorize the problems and opportunities seen in the differentiating urban typologies along Ayvali Creek, by scoring and prioritizing them with an evaluation matrix. With matrix results, planning and design proposals focused on precipitation water integrated into the existing blue-green infrastructure system for the character of the area have been developed.

Sustaining Esturial Creeks: Water Corridors in Mitigating Flooding in Manila, Philippines

This paper articulates that estuarial creeks as water corridors are essential part of urban flooding mitigation. These water corridors drain excess water from the city to the bay area reducing inland flooding while at the same time flushing pollutants during tidal changes. Using an institutional analysis, it is argued that estuarial creek rehabilitation in the City of Manila, Philippines is based on mandate, policies, legal frame, and programs. Results show that the estuarial creeks have been silent witnesses to the changing human landscape of Manila. These water corridors in congested Manila have been cleared, cleaned and widened by government agencies but were not maintained as natural space breaks in mitigating flood due to short term targets. Their deteriorating conditions have added to Manila’s waterway misery. In conclusion, the rehabilitation of the esteros is a reflection of the institutional arrangements in managing the waterway system in Metro Manila.

A safety assessment for the Guanlei Port – Qingsheng Port water corridors on the Lancang – Mekong River

ABSTRACT The water corridors between the Guanlei Port and the Qingsheng Port on the Lancang – Mekong River are important waterway for Yunnan and Southeast Asian countries. However, there are certain unpredictable safety hazards due to its location bordering multiple countries, complex terrain, sparse human settlements and inconvenient transportation. To help enhancing the safety of the Lancang – Mekong River international waterway, this paper used satellite imagery to interpret safety factors such as fault structures, channel width, rapids, vegetation coverage, river curvature, human settlements and transportation conditions. Based on analytic hierarchy process (AHP) , this research assessed the shipping safety of the waterway, analysed the effects of various factors on navigation, and made suggestions on the shipping safety which is important in the border areas. The results show that the Meisai section of the Mekong River has the shipping safety at level 1 where the limited joint patrol is proposed. The navigation channel from Guanlei Port to Wanxianwotang has the shipping safety at levels 2 & 3 where the intermediate effort of the joint patrol is suggested. The waterway from Wanxianwotang to Wannanpen has the shipping safety at levels 4 & 5 where the strong presence of the joint patrol is recommended.

Construction and optimization of green space ecological networks in urban fringe areas: A case study with the urban fringe area of Tongzhou district in Beijing

Rapid urbanization has engendered increased fragmentation of urban green spaces combined with declining green space connectivity. This situation is significant in urban fringe areas wherein rural areas transition to urban spaces. Therefore, it is important to understand how to scientifically and rationally construct green space ecological networks, connect fragmented habitats, and protect biodiversity and regional ecological security. Here, we used geographic information system and remote sensing technology to address the ecological sources via morphological spatial pattern analysis and ecological connectivity index analysis methods. The minimum cost distance method was used to generate a potential corridor. The green space ecological network system of the study area was constructed based on its green space landscape pattern. Qualitative and quantitative analysis provided targeted recommendations for green space ecological network optimization in the study area. The results showed that in the study area, the level of the fragmentation was high. Although the number of urban green space patches was significant, the area of the patches was small. Despite the potential corridor not covering the study area evenly, the optimized green space corridor increased the secondary ecological source area. The network system for green space corridors comprised water corridors, road corridors, and ecological restoration sites.

Water nano-diffusion through the Nafion fuel cell membrane

Nafion, an amphiphilic polymer based on fluorocarbon backbones and acid groups, is probably the most widely used fuel cell membranes. According to its hydration level it self-organizes leading to nano-cavities through which water diffuse. The diffusion of water that controls the protonic transport is then central in the conversion of chemical energy to the electrical one. Recently, a sub-diffusive and heterogeneous dynamics of water were experimentally evidenced paving the way for more efficient fuel cell membranes. Fundamentally, this dynamics which occurs at the nanoscale needs to be microscopically understood. Molecular dynamics simulations are thus performed to locally examine the water dynamics and its relation with the water and Nafion structure. The sub-diffusive regime is numerically corroborated and two sub-diffusive to diffusive transitions are found. The first is time dependent whereas the second is rather water uptake dependent. The sub-diffusive regime is ascribed to the water molecules strongly anchored close to the acid groups. We show that the sub-diffusive to diffusive time transition is the result of the elapsed time before to escape from the attractive interactions of the acid groups. The diffusive regime is recovered far from the acid groups in a homogeneous water phase that is the result of the percolation of the hydrogen bonding network. The progressive transition between sub-diffusive to diffusive regime as a function of the hydration level is due to the respective weight of diffusive dynamics that increases with respect to the sub-diffusive regime given the increase in diffusive pathways as the expense of the localized dynamics. Close to the fluorocarbon backbones the dynamics of water is also sub-diffusive but faster whereas time dynamical transition is not observed. Furthermore we highlight the existence of water corridors based on the hydrogen bonds between molecules forming single file structure in line with a sub-diffusive dynamics. These water corridors are thus possible conducting pathways of protons in a Grotthuss mechanism. Structurally we depict an interdigitated structure where the sulfonate are interleaved. Eventually, at high water uptake, we exhibit the self-organizing of Nafion leading to a phase separation between water and the Nafion membrane. We establish a specific interfacial organization of the hydrophilic sulfonate groups involving a water/Nafion interface.

A condition-based dynamic segmentation of large systems using a Changepoints algorithm: A corroding pipeline case

Large structures are systems composed by a significant number of components with parallel or series distributions. How these components fail and interact, aggravate the complexity of the main structure reliability calculation. Some methods commonly proposed to reduce this complexity by dividing the system into segments of similar properties using dynamic or static approaches. Dynamic segmentations may depend on how aggressive is the structure’s surrounding conditions (e.g., the soil properties). Static segmentations could be given by fixed distances. However, in a few cases, these divisions follow a condition-based approach. This paper proposes an alternative dynamic segmentation to identify preliminary critical segments based on a Changepoint approach and data obtained from inspections. Changepoints algorithms have been used to determine changes in spatial measurements for a further reliability evaluation with appropriate limit state functions. This work focuses on onshore pipelines subjected to corrosion defects based on information obtained from In-Line Inspections (ILI). Onshore pipelines cross through a variety of soils, water corridors, and densely populated areas promoting spatial-dependent degradation processes like corrosion. ILI inspections are commonly used to identify the condition of the pipeline in terms of the remaining wall and location of metal loss at the inner and outer walls by using magnetic or ultrasonic instruments. Based on a burst failure limit state, the segments obtained with the changepoints approach are compared with a soil and static segmentations. The results indicate that the proposed approach could identify the main critical points of the pipeline using segments with statistical significance.

Seismic evidence for change of the tectonic regime in Messinian, northern Marmara Sea, Turkey

New Chirp seismic data collected from the northern margin of the Marmara Sea in June 2015 and previous Sparker seismic profiles recorded in 1999 suggest a change in tectonic regime in Messinian. New tectonic lineaments and fault segments were detected at offshore the Çekmece lagoons region that is located on one of the possible water corridors with the Paratethys. The faults only affect the older seismic unit (U1), which can be best outlined on the Chirp data. The E-W trending fault offshore Avcılar (OAF) borders the northern edge of a tightly folded sedimentary zone. The NNE-SSW trending fault, namely the Büyükçekmece Fault (BF), passing through the Büyükçekmece Bay, follows a buried valley. Its evolution must be related to the development of the Early Miocene – Early Pliocene Thrace-Eskişehir fault zone (TEFZ). BF and OAF indicate old tectonic activities in the region, which continued to the North Anatolian fault becoming the most dominant tectonic element in the region. The upper surface of the stratigraphic unit U1 and its terraces define the thickness of younger deposits (U2), which is thinner in the middle of the shelf. The morphology of the tightly folded zone controls those terraces, which correspond to the Bakırköy Formation and Kıraç member on land. The topmost parts of the terraces must have been eroded during sea level low-stands and cutting of the paleo-valleys. There is no evidence of any tectonic deformation or active fault in the younger seismic unit (U2).

Toward a sustainable city of tomorrow: a hybrid Markov–Cellular Automata modeling for urban landscape evolution in the Hanoi city (Vietnam) during 1990–2030

The targets and challenges of the sustainable city of tomorrow are wide. In Hanoi city (Vietnam), the sustainable aspects of the urban landscape evolution are affected by a rapid urbanization, inefficient urban spatial planning, and the pressures of contemporary socioeconomic growth. This paper describes the evolution of urban landscape in Hanoi during the period 1990–2030. The background is the urbanization and the changes in urban planning. Urban land use/land cover of Hanoi city in 1993, 2000, 2007, 2012, and 2015 is described using LANDSAT satellite images. Land use/land cover of Hanoi in 2030 is projected by the Markov–cellular automata, which are a hybrid model of Markov chain analysis, multi-criteria evaluation, and cellular automata. The results show that Hanoi is becoming a metropolis, gradually having more dynamics and more diversity, but having less green in its pattern until 2030. All over Hanoi city, the built-up areas expanded, while the non-built area and water bodies narrowed. Residential, industrial, commercial, and service areas grow increasingly faster and become dense in the southwestern and southeastern parts of the city. New lakescapes and water corridors orient new urban development. Green areas become smaller and more fragmented. Agricultural rings have been cleared and replaced by new urban areas. Planning and managing the urban evolution toward sustainable development are imperative in Hanoi. The methods described in this paper can be effective tools expected to help planners, managers, and residents to deal with these concerns in the future. Moreover, socioeconomic development, environmental protection, improving urban planning efficiency, and integrating local governance into urban planning should be prioritized for a sustainable Hanoi city in the future.

Application of species distribution models for protected areas threatened by invasive plants

Local species distribution models (SDMs) were constructed for three of the most harmful invasive alien plant species (Fallopia spp., Solidago spp. and Heracleum mantegazzianum) in the Kokořínsko Protected Landscape Area (Czech Republic), using Natura 2000 habitat types and other environmental conditions as predictors for the SDMs. Presence or absence data (recorded by field mapping) was entered into the SDMs and used to predict the potential distribution of particular species. Here, we critically evaluate the accuracy of the models and assess their applicability for natural resource protection. Variables such as habitat and soil type tend to dictate the current distribution of Solidago spp., while distance from roads and water corridors and elevation are important for Fallopia spp. distribution. For Solidago spp., ‘generalised boosted models’ and ‘generalised additive models’ were considered the most suitable algorithms. For Fallopia spp., however, the predictive power of the models tended to be weak, while the number of localities was too low for SDMs in the case of H. mantegazzianum. The number of initial localities containing invasive alien species was an important factor for making significant predictions of potential distribution. In general, the predictive power of the models was too low when using less than 10 localities; for good predictive power at the local scale, we suggest that at least 100 localities/100km2 are used.

Microbial biofilms as one of the key elements in modulating ecohydrological processes in both natural and urban water corridors

Fluvial corridors such as streams and urban canals are critical components of the landscape and are key ecohydrological assets. They are essential to landscape function and are vulnerable to anthropogenic pressures. Energy and nutrient budgets in such corridors are dominated by processes associated with detrital organic matter and are mediated by microorganisms that mainly reside in biofilms. Here, we review the major hydrologic factors shaping biofilms in natural and urban water corridors, and propose the integration of single-cell visualization techniques with other broad-scale approaches (genomics) to better understand structure–function coupling in such complex microbial communities. We, further, provide evidence that it is possible to visualize specific bacterial clusters and autotrophic microorganisms within the matrix of natural biofilms from urban canals. This can then guide the development of ecohydrological approaches and management interventions to harness ecological services mediated by biofilms, with enormous implications also by a sanitary point of view.

Effects on river macroinvertebrate communities of tsunami propagation after the 2011 Great East Japan Earthquake

Summary The 2011 Great East Japan Earthquake generated extreme tsunami waves that entered river mouths, causing strong and long‐distance propagation along the water corridors. This study reports the first empirical survey of this rare and extreme ecological impact of tsunami propagation on river communities. We sampled macroinvertebrate communities at 15 river sites on the Sendai Plain in Northeast Japan along a gradient of tsunami disturbance intensity [i.e. altitude: range = 1–29 m above sea level (a.s.l.)] two and 16 months after the earthquake. In comparison with data collected before the tsunami, we found evidence of significant reductions in taxon richness (−54% on average) and total abundance (−91%) after the tsunami in inundated river reaches (up to 25 km from the river mouth). There were large spatial variations in local impacts, with altitudes of 7–9 m a.s.l. separating heavily damaged inundated communities from intact non‐inundated communities. The degraded communities exhibited variable recovery rates extending beyond 16 months after the tsunami. Mobility trait analysis revealed a relatively rapid recovery of swimmers (e.g. Baetis), reflecting their high mobility and active drift behaviours in the recolonisation phase. We observed the rare phenomenon of ‘upstream drift’ of marine worms (Phyllodocidae) to freshwater rivers in three of the 10 inundated sites. These survived in fresh water for up to 14 months, suggesting that some marine‐derived immigrants can persist in fresh water for extended periods.

Integrating demographic and genetic effects of connections on the viability of an endangered plant in a highly fragmented habitat

Classical ecological theories state that the viability of small metapopulations is critically related to: (1) the correlation of local population dynamics, (2) the possibility of extinct patch re-colonisation, and (3) the effects of genetic deterioration. Recent works suggested that these factors are not independent because dispersal might affect both re-colonisation and genetic rescue processes and because connectivity between habitat patches may be related to their environmental synchrony. Close patches may exhibit both high connectivity and synchronisation of their environments.Here, we examined these effects in the endangered plant Ranunculus nodiflorus that inhabits temporary water puddles, where water corridors constitute the vector (1) allowing seed dispersal throughout puddle networks and (2) leading to synchrony of local environmental factors. We utilised a demo-genetic metapopulation model to show how the antagonistic effects of connectivity and synchrony lead to complex interactions between the species’ biology and network configuration. We specifically demonstrated that (1) when an effective seed bank occurs, viability is maximised either for systems of numerous small independent networks (not connected and not synchronised), or for one single large network, while intermediate situations lead to a dramatic increase of the extinction risk; (2) genetic deterioration has notable negative effects on viability only in situations where environmentally driven extinction is buffered by the presence of a seed bank and network configuration; and (3) temporary connections among networks lead to a dramatic reduction of the extinction risk. The implementation of such connections is an efficient management option for the species.