Heartworm (Dirofilaria immitis) is a parasitic roundworm that causes a zoonotic disease known as dirofilariosis. Little is known about the role of wild carnivores serving as reservoirs in nature. Therefore, we examined 738 hearts and lungs of free ranging wild carnivores from Serbia to determine the presence of adult heartworms. During the period 2009-2013, the prevalence in golden jackals (Canis aureus) was 7.32%, in red foxes (Vulpes vulpes) 1.55%, in wolves (Canis lupus) 1.43%, and in wild cats (Felis silvestris) 7.69%. No adult heartworm specimens were found in beech martens (Martes foina), stone martens (Martes martes), European polecats (Mustela putorius), badgers (Meles meles) or otter (Lutra lutra). The highest recorded prevalence was in 2013 (7.30%) and the lowest in 2012 (1.6%). In jackals, the prevalence was higher in males (10%) than in females (4.06%), while in foxes the prevalence was 1.75% in males and 1.26% in females. The most infected host was a wolf in which 37 adult specimens were found. Because of the potentially significant role in the life cycle of D. immitis, populations of wild carnivores in Europe should be further examined and tested for heartworm infections.

Landscape experiments of fluvial environments such as rivers and deltas are often conducted with live seedlings to investigate effects of biogeomorphological interactions on morphology and stratigraphy. However, such experiments have been limited to a single species, usually alfalfa (Medicago sativa), whereas important environments in nature have many different vegetation types and eco‐engineering effects. Landscape experimentation would therefore benefit from a larger choice of tested plant species. For the purpose of experimental design our objective was to identify fast‐germinating and fast‐growing species and determine their sensitivity to flow conditions during and after settling, their maximum growth, hydraulic resistance and added bank strength. We tested germination time and seedling growth rate of 18 candidate species with readily available seeds that are fast growing and occur at waterlines, plus Medicago sativa as a control. We selected five species that germinate and develop within days and measured properties and eco‐engineering effects depending on plant age and density, targeting typical experimental conditions of 0–0.3 m/s flow velocity and 0–30 mm water depth. Tested eco‐engineering effects include bank strength and flow resistance. We found that Rumex hydrolapathum can represent riparian trees. The much smaller Veronica beccabunga and Lotus pedunculatus can represent grass and saltmarsh species as they grow in dense patches with high flow resistance but are readily erodible. Sorghum bicolor grows into tall, straight shoots, which add significantly to bank strength, but adds little flow resistance and may represent sparse hardwood trees. Medicago sativa also grows densely under water, suggesting a use for mangroves and perhaps peat. In stronger and deeper flows the application of all species changes accordingly. These species can now be used in a range of landscape experiments to investigate combined effects on living landscape patterns and possible facilitation between species. The testing and treatment methodology can be applied to new species and other laboratory conditions. © 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd. © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.

Infectious agents are part of food webs and ecosystems via the relationship with their host species that, in turn, interact with both hosts and non-hosts. Through these interactions, infectious agents influence food webs in terms of structure, functioning and stability. The present literature shows a broad range of impacts of infectious agents on food webs, and by cataloguing that range, we worked towards defining the various mechanisms and their specific effects. To explore the impact, a direct approach is to study changes in food-web properties with infectious agents as separate species in the web, acting as additional nodes, with links to their host species. An indirect approach concentrates not on adding new nodes and links, but on the ways that infectious agents affect the existing links across host and non-host nodes, by influencing the 'quality' of consumer-resource interaction as it depends on the epidemiological state host involved. Both approaches are natural from an ecological point of view, but the indirect approach may connect more straightforwardly to commonly used tools in infectious disease dynamics.

Abstract. Vegetation enhances bank stability and sedimentation to such an extent that it can modify river patterns, but how these processes manifest themselves in full-scale estuarine settings is poorly understood. On the one hand, tidal flats accrete faster in the presence of vegetation, reducing the flood storage and ebb dominance over time. On the other hand flow-focusing effects of a tidal floodplain elevated by mud and vegetation could lead to channel concentration and incision. Here we study isolated and combined effects of mud and tidal marsh vegetation on estuary dimensions. A 2-D hydromorphodynamic estuary model was developed, which was coupled to a vegetation model and used to simulate 100 years of morphological development. Vegetation settlement, growth and mortality were determined by the hydromorphodynamics. Eco-engineering effects of vegetation on the physical system are here limited to hydraulic resistance, which affects erosion and sedimentation pattern through the flow field. We investigated how vegetation, combined with mud, affects the average elevation of tidal flats and controls the system-scale planform. Modelling with vegetation only results in a pattern with the largest vegetation extent in the mixed-energy zone of the estuary, which is generally shallower. Here vegetation can cover more than 50 % of the estuary width while it remains below 10 %–20 % in the outer, tide-dominated zone. This modelled distribution of vegetation along the estuary shows general agreement with trends in natural estuaries observed by aerial image analysis. Without mud, the modelled vegetation has a limited effect on morphology, again peaking in the mixed-energy zone. Numerical modelling with mud only shows that the presence of mud leads to stabilisation and accretion of the intertidal area and a slight infill of the mixed-energy zone. Combined modelling of mud and vegetation leads to mutual enhancement with mud causing new colonisation areas and vegetation stabilising the mud. This occurs in particular in a zone previously described as the bedload convergence zone. While vegetation focusses the flow into the channels such that mud sedimentation in intertidal side channels is prevented on a timescale of decades, the filling of intertidal area and the resulting reduction in tidal prism may cause the infilling of estuaries over centuries.

Hydromorphological data for many estuaries worldwide is scarce and usually limited to offshore tidal amplitude and remotely-sensed imagery. In many projects, information about morphology and intertidal area is needed to assess the effects of human interventions and rising sea-level on the natural depth distribution and on changing habitats. Habitat area depends on the spatial pattern of intertidal area, inundation time, peak flow velocities and salinity. While numerical models can reproduce these spatial patterns fairly well, their data need and computational costs are high and for each case a new model must be developed. Here, we present a Python tool that includes a comprehensive set of relations that predicts the hydrodynamics, bed elevation and the patterns of channels and bars in mere seconds. Predictions are based on a combination of empirical relations derived from natural estuaries, including a novel predictor for cross-sectional depth distributions, which is dependent on the along-channel width profile. Flow velocity, an important habitat characteristic, is calculated with a new correlation between depth below high water level and peak tidal flow velocity, which was based on spatial numerical modelling. Salinity is calculated from estuarine geometry and flow conditions. The tool only requires an along-channel width profile and tidal amplitude, making it useful for quick assessments, for example of potential habitat in ecology, when only remotely-sensed imagery is available.