Dense Patches Research Articles

<strong><em>Physoglossus</em>: A new ground beetle genus of the enigmatic tribe Physocrotaphini Chaudoir, 1862 (Carabidae: Anthiinae) from the Western Ghats, a global hotspot of Biodiversity in south west India</strong>

A new genus of enigmatic tribe Physocrotaphini, Physoglossus gen. nov., with a new species Ph. devagiriensis sp. nov. from a dry deciduous forest in the rain shadow belt of the south Western Ghats in south west India is described. Presence of mentum with bifid median tooth and large oval depression with dense patch of filamentous setae on 2nd and 3rd male sternites makes it intermediate to the Physocrotaphini genera, Pogonoglossus, Foveocrotaphus and Physocrotaphus. Key words: new ground beetle species, Anthiinae, the Western Ghats, India

The commercially important shoemaker spinefoot, Siganus sutor, connects coral reefs to neighbouring seagrass meadows.

Spatial management of fish populations can potentially be optimized by determining the area of influence of a particular species. We performed an acoustic tagging study implemented on Denis Island in the Seychelles to assess the area of influence of the heavily targeted shoemaker spinefoot, Siganus sutor. We investigated whether this species acts as a mobile link between coral patches and seagrass meadows, and whether their movements differed between day and night. The study incorporated an array of 22 acoustic stations deployed within dense coral patches, seagrass meadows and mixed habitats of both seagrass and coral. Fifteen S. sutor carrying internal acoustic tags were monitored from November 2016 until May 2017. Detection patterns revealed them to be diurnal herbivores, with only rare nocturnal movements. Home-range estimates showed that individuals differed in their spatial range extents and habitats used, covering ~15% of the total shallow subtidal coastline of the island. However, they displayed very small daily movements (<200 m), concentrated mainly around sites within mixed coral and seagrass habitats. An optimal number of detections was recorded when the coral to seagrass area ratio was approximately 1.6:1. This ratio was confirmed through statistical prediction modelling. Identification of such links of commercially important species between networked habitats may help authorities consider incorporating seagrass meadows of the Seychelles into management discussions, which are currently lacking.

The Banj oak Quercus leucotrichophora as a potential mitigating factor for human-langur interactions in the Garhwal Himalayas, India: People’s perceptions and ecological importance

Crop-foraging by primates is a rapidly growing concern. Effective mitigation strategies are urgently required to resolve this issue. In the Garhwal Himalayas, local people’s high dependency on forest resources is a major cause of habitat loss, which paves the way for human-primate interactions in this area. To investigate the socioeconomic factors that might explain langur crop-foraging, we conducted structured interviews among 215 households in the Garhwal Himalayas in India. We also examined langur resource use by monitoring their feeding and sleeping site activity. Less agricultural land, less agricultural production, and possession of large numbers of livestock significantly predicted villagers reporting crop-foraging events, although economic status of the correspondents did not have any effect. Perception of the villagers about reduction in forest resource was significantly affected by the amount of livestock possessed by the villagers. Our observations suggested that Banj oak Quercus leucotrichophora was the dominant species (59.2%, N = 306) in the pool of sleeping trees used by the langurs. Langurs also showed a preference in their use of sleeping sites and feeding sites, which were different from that expected by chance. Sleeping sites with high density of oak were re-used most frequently. Similarly, dense oak patches were also the preferred feeding patches. Thus, we suggest replanting of oak trees and conservation of intact oak patches, environmental education outreach, and empowerment of women in the community as potential mitigating factors to lessen the interaction between humans and langurs.

Landscape-scale drivers of mammalian species richness and functional diversity in forest patches within a mixed land-use mosaic

Abstract We estimated the influence of habitat fragmentation characteristics (patch size, isolation and number of neighbouring patches), habitat and land management types at the community level, specifically, on species richness, functional- α (alpha), guild- and β (beta) diversity of forest and dense bush habitat patches in southern KwaZulu-Natal Province, South Africa. We used mammal camera-trap data from 245 survey points across 157 habitat patches. We partitioned β diversity-change (βtotal) into its nestedness (βnestedness) and turnover (βturnover) components. Species turnover was the dominant component of species β diversity, while nestedness was the dominant component of functional β diversity. Carnivore and insectivore diversity significantly decreased with increasing isolation from large patches. Patch size did not influence species-, functional- or guild diversity. We found that the number of neighbouring patches nested within the mixed land-use matrix were important drivers of functional- and species α diversity, carnivore- and herbivore diversity. Fragmentation characteristics alone did not explain the patterns of diversity tested, but habitat and land management type were important factors for all diversity indices. We recommend incentivised protection for privately owned forest patches, as they act as stepping stones for movement of forest-associated mammals throughout the landscape. Furthermore, we emphasise the importance of habitat quality and of effective management of forest in mixed land-use mosaic landscapes to prevent further degradation.

Land-use and coverage in the structure of the landscape in a Tropical Dry Forest in northeast Brazil

Landscape Ecology using GIS is applied to understand the effects of forest fragmentation and makes it feasible mainly for extensive areas, through the possibility of analyzing both the variety of units that compose it in time. This study aims to analyze the land use and coverage of tropical dry forests and to characterize their landscape structure in an area of the municipality of Floresta, Pernambuco, Brazil, in order to understand how the landscape configuration can influence the conservation. Orbital images were used from LANDSAT, and the classification was performed in the QGIS 2.18 software using the Maximum Likelihood methodification, for the years of 2007 and 2017. A circular buffer was incorporated around the area of study to analyze the structural patterns in the context of the landscape. Five thematic classes were used: dense vegetation, sparse vegetation, exposed soil, grassland, and water. The metrics were obtained through the Patch Analyst tool only to the class of dense vegetation. It is noted that much of the dense vegetation has become sparse. There was a reduction of exposed soil and an increase in grassland areas, which may indicate a regeneration process of the vegetation. The fragments of dense vegetation with more substantial dimensions are on constant exploratory actions and are the most affected with the reduction of size. Furthermore, climatic factors, periods of drought, and the presence of livestock may also affect the fragmentation of dense vegetation patches. Therefore, the landscape became heterogeneous, and a tendency was observed to increase the fragmentation, mainly in the more significant spots.

Active acoustic telemetry tracking and tri-axial accelerometers reveal fine-scale movement strategies of a non-obligate ram ventilator

BackgroundCalifornia horn sharks (Heterodontus francisci) are nocturnally active, non-obligate ram ventilating sharks in rocky reef habitats that play an important ecological role in regulating invertebrate communities. We predicted horn sharks would use an area restricted search (ARS) movement strategy to locate dense resource patches while minimizing energetic costs of travel and nighttime activity. As ectotherms, we predicted environmental temperature would play a significant role in driving movement and activity patterns.MethodsContinuous active acoustic tracking methods and acceleration data loggers were used to quantify the diel fine-scale spatial movements and activity patterns of horn sharks. First passage time was used to identify the scale and locations of patches indicative of ARS. Activity was assessed using overall dynamic body acceleration (ODBA) as a proxy for energy expenditure. Behavior within a patch was characterized into three activity patterns: resting, episodic burst activity, and moderate, consistent activity.ResultsAfter resting in daytime shelters, individuals travelled to multiple reefs throughout the night, traversing through depths of 2–112 m and temperatures of 10.0–23.8 °C. All sharks exhibited area restricted search patch use and arrived at their first patch approximately 3.4 ± 2.2 h (mean ± SD) after sunset. Sharks exhibited moderate, consistent activity in 54% of the patches used, episodic burst activity in 33%, and few (13%) were identified as resting at night. ODBA peaked while sharks were swimming through relatively deeper (~ 30 m), colder channels when traversing from one patch to the next. There was no consistent pattern between ODBA and temperature.ConclusionsWe provide one of the largest fine-scale, high-resolution paired data sets for an elasmobranch movement ecology study. Horn sharks exhibited ARS movement patterns for various activity patterns. Individuals likely travel to reefs known to have profitable and predictable patches, potentially tolerating less suitable environmental temperatures. We demonstrate how gathering high-resolution information on the movement decisions of a community resident enhances knowledge of community structure and overall ecosystem function.

External conditions drive optimal planting configurations for salt marsh restoration

Abstract Coastal salt marshes are threatened by erosion from storminess and sea level rise, with resulting losses in flood protection, wildlife and recreational space. Although more than $1 billion has been spent to reconcile losses, restoration has had varying success because of poor survival of planted patches in challenging wave and current conditions. Marsh expansion after colonization or replanting is regulated by positive and negative feedbacks between vegetation density and sediment capture. Dense vegetation stimulates sediment capture and vertical patch growth, but negatively constrains patch expansion by concentrating hydrological energy into erosion gullies along patch edges. Conversely, low‐density vegetation may not simulate enough sediment capture, which increases plant dislodgement mortality. The strengths of positive and negative feedbacks will vary with wave exposure, but this has never been tested in natural conditions. We observed density‐dependent sediment feedbacks, survival and lateral expansion by Sporobolus anglicus patches (0.8 × 0.8 m) planted at three levels of vegetation density, at each of three levels of wave forcing (three sites). We found interactive effects of plant density and forcing on the strength of positive and negative feedbacks. Density‐dependent feedbacks only emerged in moderate and exposed conditions: classic marsh tussock patch shapes, which arise due to combined positive (vertical growth) and negative (gullies) feedbacks, were only associated with high density vegetation under exposed conditions. At high exposure, survival was enhanced by dense planting, which diverted energy away from the vegetation. In sheltered conditions, expansion was the greatest at medium density, while dense patches had high mortality and erosion. Synthesis and applications. Success of wetland restoration clearly hinges on considering interactions between environmental stress and planting density. In challenging high‐exposure settings, dense planting in large patches should maximize success, as plant facilitation boosts sediment capture and negative edge effects (gullies) will represent a diminished proportion of larger patches. Yet, benefits of dense planting will switch from positive (facilitation) to negative (competition) with reduced environmental stress, when moderate‐density planting might be optimal. Switches along stress gradients between positive and negative feedbacks are common across ecosystems. We call for wider integration of facilitation and stress–gradient principles into restoration design to safeguard restoration successes.

Observations of vulnerable marine ecosystems and significant adverse impacts on high seas seamounts of the northwestern Hawaiian Ridge and Emperor Seamount Chain

The Northwestern Hawaiian Ridge seamounts (NHR) outside the US EEZ and the Emperor Seamount Chain (ESC) have some of the longest history and largest takes of bottom contact fisheries of any seamounts globally. Imaging surveys from four of these seamounts provide evidence of vulnerable marine ecosystems (VMEs) on all surveyed features including dense patches of octocorals, scleractinian reefs, and sponges. Crinoids and brisingids occurred patchily in high abundance. These results, records from precious coral fishery takes, and habitat suitability modeling collectively indicate an extremely high probability that deep-sea coral VMEs are widespread on all of the ESC-NHR seamounts.Evidence for significant adverse impacts (SAIs) from bottom contact fisheries was also observed on all surveyed seamounts and included large areas of barren hard substrate, with scars from bottom contact gear in 19–29% of AUV images. Stumps from arborescent corals and rubble from reef-forming corals were observed. Evidence of SAIs is further supplied by many observations of coral rubble associated with lost fishing gear. Finally coralliid octocorals, once sufficiently abundant on the targeted seamounts to support the world's largest precious coral fishery, were extremely rare on all features despite the large survey area.Based on observations of VMEs, SAIs to these VMEs, and the potential for recovery, the results presented here would indicate a closure of all NHR and ESC seamounts to bottom contact fisheries until the gear being used can be proven to not cause SAIs. Closures should include both untrawled areas and currently fished areas to allow for recovery.

Correcting Misleading Image Quality Measurements

We discuss several common image quality measurements that are often misinterpreted, so that bad images are falsely interpreted as good, and we describe how to obtain valid measurements. Sharpness, which is measured by MTF (Modulation Transfer Function) curves, is frequently summarized by MTF50 (the spatial frequency where MTF falls to half its low frequency value) But because MTF50 strongly rewards excessive sharpening, we recommend other summary metrics, especially MTF50P (the spatial frequency where MTF falls to half its peak value), that provide a more stable indication of system performance. Camera dynamic range (DR), defined as the range of exposure (scene brightness) where the image has good contrast and Signalto- Noise Ratio (SNR), Is usually measured with grayscale step charts. We have recently seen several cases where flare light radiating out from bright areas of the image fogs dense patches, causing unreasonably high DR measurements. This situation is difficult to handle with linear test charts, where the flare light is aligned with the patches, but can be handled well in charts with circular patch patterns, where the patch where pixel level ceases to decrease defines the upper DR limit.

“Little Red Jellies” in Monterey Bay, California (Cnidaria: Hydrozoa: Trachymedusae: Rhopalonematidae)

Several species of small, red, deep-sea Trachymedusae have been described and then re-described over the past 20 years, leading to some confusion in the scientific literature. This paper provides an overview of three genera (Benthocodon, Crossota, and Pectis) in the family Rhopalanematidae (Cnidaria: Hydrozoa) that have been observed and examined both in the field and in the laboratory. Twenty years of in situ observations in Monterey Bay indicate that two of the genera, Benthocodon and Pectis, are often associated with the benthic boundary layer and can occur in dense patches. They have been observed resting on soft sediments with their subumbrellar surface down but are also to be found swimming up to several hundred meters above the bottom. Individuals in the genus Crossota tend to be solitary and more pelagic in nature. Although Crossota may be found near the bottom as well, down to depths of 4000 meters, they have not been observed resting on the bottom. The three genera are morphologically similar and difficult to distinguish. As a group, they are small (< 5 cm) and sometimes darkly pigmented, making in situ identifications challenging. We show that these three genera can be differentiated morphologically and we provide a key to the genera and species common in Monterey Bay. Further, the genera differ in their depth distribution and behavior. Molecular genetics suggest that the genera and species are distinct from each other but that their taxonomy is in need of thorough revision. This paper reviews the generic characteristics along with species identifications and provides images and video (supplemental material) that may be helpful in identification.

Fluid\u2013structure interaction of flexible submerged vegetation stems and kinetic turbine blades

A fluid–structure interaction (FSI) methodology is presented for simulating elastic bodies embedded and/or encapsulating viscous incompressible fluid. The fluid solver is based on finite volume and the large eddy simulation approach to account for turbulent flow. The structural dynamic solver is based on the combined finite element method–discrete element method (FEM-DEM). The two solvers are tied up using an immersed boundary method (IBM) iterative algorithm to improve information transfer between the two solvers. The FSI solver is applied to submerged vegetation stems and blades of small-scale horizontal axis kinetic turbines. Both bodies are slender and of cylinder-like shape. While the stem mostly experiences a dominant drag force, the blade experiences a dominant lift force. Following verification cases of a single-stem deformation and a spinning Magnus blade in laminar flows, vegetation flexible stems and flexible rotor blades are analysed, while they are embedded in turbulent flow. It is shown that the single stem’s flexibility has higher effect on the flow as compared to the rigid stem than when in a dense vegetation patch. Making a marine kinetic turbine rotor flexible has the potential of significantly reducing the power production due to undesired twisting and bending of the blades. These studies point to the importance of FSI in flow problems where there is a noticeable deflection of a cylinder-shaped body and the capability of coupling FEM-DEM with flow solver through IBM.

Graph convolutional neural network for multi-scale feature learning

Automatic deformable 3D modeling is computationally expensive, especially when considering complex position, orientation and scale variations. We present a volume segmentation framework to utilize local and global regularizations in a data-driven approach. We introduce automated correspondence search to avoid manually labeling landmarks and improve scalability. We propose a novel marginal space learning technique, utilizing multi-resolution pooling to obtain local and contextual features without training numerous detectors or excessively dense patches. Unlike conventional convolutional neural network operators, graph-based operators allow spatially related features to be learned on the irregular domain of the multi-resolution space, and a graph-based convolutional neural network is proposed to learn representations for position and orientation classification. The graph-CNN classifiers are used within a marginal space learning framework to provide efficient and accurate shape pose parameter hypothesis prediction. During segmentation, a global constraint is initially non-iteratively applied, with local and geometric constraints applied iteratively for refinement. Comparison is provided against both classical deformable models and state-of-the-art techniques in the complex problem domain of segmenting aortic root structure from computerized tomography scans. The proposed method shows improvement in both pose parameter estimation and segmentation performance.

Micro level analyses of environmentally disastrous urbanization in Bangalore.

Indian metropolitan (tier I) cities have been undergoing rapid urbanization during the post-globalization era with the unprecedented market interventions, which have led to the rapid land cover changes affecting the ecology, climate, hydrology, and local environment. The unplanned urbanization has given way to the dispersed, haphazard growth at the city outskirts with the lack of basic amenities and infrastructure as the planners lack advance information of sprawl regions. This has necessitated understanding and visualization of urbanization patterns for planning towards sustainable cities. The analyses of urban dynamics during 1973-2017 using temporal remote sensing data reveal 1028% increase in urban area with the decline of 88% vegetation and 79% of water bodies. Consequences of the unplanned urbanization are the increase in greenhouse gas emissions, decline in vegetation cover, loss of groundwater table (from 28 to 300m), contamination of water sources, increase in land surface temperature, increase in disease vectors, etc. An attempt is made to understand the implications of unplanned growth at the micro level by considering the prime growth poles such as Peenya Industrial Estate (PIE), Whitefield (WF), Bangalore South Region (BSR). The spatial analyses reveal the decline of vegetation and open spaces with intense urbanization of 86.35% (in BSR), 87.39% (PIE) and 81.61% (WF) in 2017. WF witnessed the drastic transformation from agrarian ecosystem to a concrete jungle during the past four decades. Spatial patterns of urbanization were assessed through the landscape metrics and rule-based modeling which confirms intense urbanization with single class dominance. Specifically, NP metrics depicts PIE region had sprawl growth till 2003 with numerous patches and is transformed by 2017 it has become to a single dense urban patch. This necessitates appropriate planning strategies to mitigate further erosion of environmental resources and ensure clean air, water, and environment to all residents.

Caracteres vegetativos y reproductivos de Bromelia serra (Bromeliaceae): Variaciones a distintas escalas espaciales y efectos del ambiente lumínico

Las bromeliaceas terrestres son comunes en los bosques neotropicales. En particular, en el sotobosque de los quebrachales chaquenos existen parches densos de Bromelia serra, que crecen bajo condiciones microambientales heterogeneas. El ambiente luminico afecta la asignacion de biomasa a distintos organos, por lo que las plantas que crecen bajo distintas condiciones luminicas presentan una arquitectura diferente. A su vez, el tamano de la planta y los factores ambientales y geneticos condicionan la asignacion de biomasa a los caracteres reproductivos. Para evaluar el efecto del ambiente luminico sobre los caracteres vegetativos y reproductivos se seleccionaron cuatro parches en cada uno de tres sitios separados por 500 m, en un quebrachal de la Cuna Boscosa Santafesina. En cada parche se seleccionaron cuatro plantas adultas. A cada planta se le midio la altura, el diametro, la longitud y el ancho de la hoja mas larga, el diametro de la infrutescencia, el numero, el peso y el tamano de los frutos y el numero de semillas. La caracterizacion de la apertura del dosel sobre cada planta se hizo con fotografia hemisferica. Los Modelos Lineales Generales Mixtos muestran que el porcentaje de la varianza explicado por la variacion espacial (factores aleatorios representando a los sitios y a los parches) es mayor para caracteres vegetativos que para reproductivos. La mayor proporcion de esta varianza se registro a nivel de parche para los caracteres vegetativos y a nivel de sitio para los reproductivos. Mediante un Modelo de Ecuaciones Estructurales basado en Modelos Lineales Generales Mixtos se determino que el ambiente luminico afecta de forma directa e indirecta el diametro de la infrutescencia. Las plantas expuestas a mayor apertura de dosel son mas pequenas y tienen menor cantidad y tamano de frutos. Esto resulta en infrutescencias mas chicas, lo cual destaca el efecto indirecto del ambiente luminico sobre los caracteres reproductivos.https://doi.org/10.25260/EA.19.29.3.0.826

Microbial communities associated with distance- and density-dependent seedling mortality in a tropical rainforest

The high levels of diversity within tropical rainforest communities has been linked to non-random patterns of seedling mortality with several studies implicating pathogenic plant–microbe interactions in driving mortality processes. Despite the proposed importance of microorganisms in maintaining rainforest diversity, few studies have investigated soil community dynamics in relation to non-random mortality processes. A mechanistic understanding of microbial processes that help create rainforest diversity is critical for the conservation of these ecosystems. This study investigated microbial community dynamics that may underpin distance- and density-dependent mortality in the long-term forest dynamics plot, Davies Creek, in tropical Far North Queensland using community fingerprinting. We hypothesized that: (1) microbial involvement in distance-dependent seedling mortality would result in an increase in community similarity or the presence of predictor OTUs in conspecific adult tree rhizospheres, relative to physically nearby heterospecifics; (2) on average, plant species identified as having a history of distance dependent seedling mortality would exhibit more similar microbial communities among their conspecific individuals, than those that did not; and (3) dense patches of conspecific seedlings would promote the assembly of distinct soil microbial communities, which may be involved in density-dependent seedling mortality. We found no evidence of rhizosphere community similarity amongst adult plant rhizospheres. However, the presence of densely germinating seedlings altered the soil communities relative to seedling-sparse soils, enriching different OTUs depending on the patch location.

Upstream and Downstream Boundary Conditions Control the Physical and Biological Development of River Deltas

AbstractRelative sea level rise is depleting coastal land. Success in coastal restoration depends on understanding interactions between physical and biological processes that influence landscape change. We present results from flume experiments examining the coevolution of vegetation and delta channel networks. We show that channel mobility—controlled by upstream and downstream boundary conditions and delta size—controls vegetation colonization. The spatial patterns of plants in turn control the stability and spatial distribution of channels. Experiments with low‐channel mobility develop large, dense plant patches that become denser over time and stabilize channels. Experiments with more mobile channels have sparse vegetation patterns that limit vegetation growth within existing patches, maintaining sparse, patchy vegetation. Thus, the ecogeomorphic development of deltas depends on the rate of channel lateral migration and avulsion, suggesting that upstream and downstream boundary conditions control both the physical and biological evolution of coastal landscapes.

A network theoretic study of potential invasion and spread of Lantana camara in a part of Rajaji Tiger Reserve, India

Ecosystems are constantly under threat by invasive species which alter existing ecological networks as they spread. We use Geographic Information System methods coupled with complex network analysis to model the movement and spread of Lantana camara in Rajaji Tiger Reserve, India, as understanding spatial aspects of the spread mechanism are essential for better resource management in the region. Lantana mapping was carried out by field observations along multiple transects and plots, and the data generated was used as input for maximum entropy modelling to identify land patches in the study area that are favourable for lantana growth. The patch information so obtained was integrated with a raster map generated by identifying different topographical features in the study area which are favourable for lantana growth. The integrated data was analysed with a complex network perspective, where relatively dense and large potential lantana distribution patches were considered as vertices, connected by relatively sparse and thin potential lantana continuities, identified as edges. The network centrality analysis reveal key patches in the study area that play specialized roles in the spread of lantana in a large region. Hubs in the lantana network are primarily identified as dry seasonal river beds. The lantana network is found to exhibit small-world architecture with a well formed community structure. We infer that the above properties of the lantana network are major contributors in regulating the movement and spread of the plant through the entire region of study.

High-sensitivity microseismic monitoring: Automatic detection and localization of subsurface noise sources using matched-field processing and dense patch arrays

Recent advancements in seismic data acquisition and computational power have enhanced the deployment of dense seismic monitoring networks. The growing volume of recorded data requires the development of automated techniques to monitor and image zones of seismicity. We have developed an automatic detection and localization method that demands minimal a priori information for retrieval of the spatial distribution of subsurface noise sources (including, but not limited to, microseismic activity), in a reservoir and in the near vicinity during a hydraulic fracturing treatment. This method is based on matched-field processing (MFP), which takes advantage of the phase coherence that is recorded at dense arrays of sensors to localize noise sources. MFP is applied with a distributed set of patch arrays in the context of geophysics exploration. The MFP approach is applied to ambient noise recordings, and it provides results that are consistent with the classic localization methods applied to high-amplitude microseismic signals (in particular, using the relative template-based method). Furthermore, MFP provides enhanced sensitivity of detection and spatially extended information about structural heterogeneities. MFP opens a route to continuous, automatic, statistics-based, and high-sensitivity reservoir monitoring and imaging for geophysics exploration. Potential applications can also be envisaged for seismic monitoring of volcanic and geyser activities, and for other types of hydrothermal activity.

Species selection and assessment of eco‐engineering effects of seedlings for biogeomorphological landscape experiments

AbstractLandscape 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 &amp; Sons Ltd. © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley &amp; Sons Ltd © 2019 The Authors Earth Surface Processes and Landforms Published by John Wiley &amp; Sons Ltd.

Fire Exclusion Destroys Habitats for At-Risk Species in a British Columbia Protected Area

Fire exclusion and suppression has altered the composition and structure of Garry oak and associated ecosystems in British Columbia. The absence of frequent low severity ground fires has been one of the main contributors to dense patches of non-native grasses, shrubs, and encroaching Douglas-fir trees in historical Garry oak dominated meadows. This case study uses remote sensing and dendrochronology to reconstruct the stand dynamics and long-term fire history of a Garry oak meadow situated within Helliwell Provincial Park located on Hornby Island, British Columbia. The Garry oak habitat in Helliwell Park has decreased by 50% since 1950 due to conifer encroachment. Lower densities and mortalities of Garry oak trees were associated with the presence of overstory Douglas-fir trees. To slow conifer encroachment into the remaining Garry oak meadows, we recommend that mechanical thinning of Douglas-fir be followed by a prescribed burning program. Reintroducing fire to Garry oak ecosystems can restore and maintain populations of plants, mammals, and insects that rely on these fire resilient habitats.