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Debris flows can grow greatly in size and hazardous potential by eroding bed and bank materials. However, erosion mechanisms are poorly understood because debris flows are complex hybrids between a fluid flow and a moving mass of colliding particles, bed erodibility varies between events, and field measurements are hard to obtain. Here, we identify the key controls on debris‐flow erosion based on a field data set that combines information on flow properties, bed conditions, and bed and bank erosion. We show that flow conditions and bed wetness jointly control debris‐flow erosion. Flow conditions describing the cumulative forces exerted at the bed during an event best explain erosion. Shear forces and particle‐impact forces are strongly correlated and act in conjunction in the erosion process. A shear‐stress approach accounting for bed erodibility may therefore be applicable for modeling and predicting debris‐flow erosion. This work provides a foundation for developing effective debris‐flow erosion models. Plain Language Summary: Debris flows are water‐laden masses of soil and rock, which are common geological hazards in mountainous regions worldwide. They can grow greatly in size and hazardous potential by eroding bed and bank materials. Limited understanding of these erosion processes, however, hampers effective hazard assessment and mitigation. Improving our understanding of erosion is challenging because debris flows are complex hybrids between a fluid flow and a moving mass of colliding particles, bed erodibility varies between events, and field measurements are hard to obtain. Here, we identify the key controls on debris‐flow erosion based on a field data set that combines information on flow properties, bed conditions, and bed and bank erosion. We show that flow properties and bed wetness jointly control debris‐flow erosion. Flow conditions that describe the cumulative forces exerted at the bed during an event best explain erosion. Shear forces and particle‐impact forces are strongly correlated and act in conjunction in the erosion process. A shear‐stress approach accounting for bed erodibility may therefore be applicable for modeling and predicting debris‐flow erosion. This work provides a foundation for developing effective debris‐flow erosion models. Key Points: Flow conditions and bed wetness jointly control debris‐flow erosion and depositionShear forces and particle‐impact forces are strongly correlated and together determine erosionA shear‐stress approach accounting for bed erodibility may be applicable for modeling debris‐flow erosion [ABSTRACT FROM AUTHOR]

Wildlife habitat selection is determined by a wide range of factors including food availability, shelter, security and landscape heterogeneity all of which are closely related to the more readily mapped landcover types and disturbance regimes. Regional wildlife habitat studies often used moderate resolution multispectral satellite imagery for wall to wall mapping, because it offers a favourable mix of availability, cost and resolution. However, certain habitat characteristics such as canopy structure and topographic factors are not well discriminated with these passive, optical datasets. Airborne laser scanning (ALS) provides highly accurate three dimensional data on canopy structure and the underlying terrain, thereby offers significant enhancements to wildlife habitat mapping. In this paper, we introduce an approach to integrate ALS data and multispectral images to develop a new heuristic wildlife habitat classifier for western Alberta. Our method combines ALS direct measures of canopy height, and cover with optical estimates of species (conifer vs. deciduous) composition into a decision tree classifier for habitat – or landcover types. We believe this new approach is highly versatile and transferable, because class rules can be easily adapted for other species or functional groups. We discuss the implications of increased ALS availability for habitat mapping and wildlife management and provide recommendations for integrating multispectral and ALS data into wildlife management. [ABSTRACT FROM AUTHOR]

Phenological patterns of the components within forest ecosystems, such as understory vegetation, are important indicators of climate variability, productivity, and additional ecosystem services such as food and habitat availability for wildlife. Proximal sensing systems can provide detailed phenological records at a relatively low cost. As interest in these datasets increases, we need additional information regarding the effect of different approaches on the scale of observations and camera field of view. In this research, we examine the impact of field of view on the capacity of cameras to detect changes in phenology of individual species in an image time series. We examine two co-located series of oblique images acquired using a fine and broad field of view and compare a number of phenological indicators, including the start and end of season derived for individual plant species. Our results indicate both fine and broad field of view camera systems are highly effective at detecting key markers of plant phenology with no significant differences between the two. This result supports environmental monitoring using cost-effective broad field of view cameras, or even--subject to some constraints--readily available camera stations installed for tourism or traffic monitoring. [ABSTRACT FROM AUTHOR]

Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems. [ABSTRACT FROM AUTHOR]

High spatial resolution images allow us to assess the spatial structure and variability of natural vegetation characteristics. In order to optimize quantitative image analysis, we looked for the optimal spatial resolution to map natural vegetation in a Mediterranean environment. The optimal spatial resolution was then related to the spatial characteristics of the scene and the mapped parameters. Based on the relation between airborne hyperspectral imagery and field dataset consisting of 227 measured plots of Leaf Area Index (LAI) and aboveground biomass, we found an optimal pixel size of 55 and 95 m for the mapping of LAI and aboveground biomass, respectively. The optimal spatial resolution we found is determined by the spatial structure of the mapped parameters on the one hand, and by the effects of shading patterns and gaps in the canopy on the other. The spatial properties of scene elements influencing the optimal spatial resolution can be detected effectively using average local variance functions and variograms, provided that these are studied at a wide spatial range. The use of an optimally sized mapping unit instead of the original 5 m pixels resulted in an improvement of mapping accuracy of 7 to 17%. It is therefore recommended that the image support used is considered carefully in all quantitative mapping projects based on remotely sensed imagery. [Copyright &y& Elsevier]

Although species richness can be determined by different mechanisms at different spatial scales, the role of scale in the effects of marine inputs on island biogeography has not been studied explicitly. Here, we evaluated the potential influence of island characteristics and marine inputs (seaweed wrack biomass and marine-derived nitrogen in the soil) on plant species richness at both a local (plot) and regional (island) scale on 92 islands in British Columbia, Canada. We found that the effects of subsidies on species richness depend strongly on spatial scale. Despite detecting no effects of marine subsidies at the island scale, we found that as plot level subsidies increased, species richness decreased; plots with more marine-derived nitrogen in the soil hosted fewer plant species. We found no effect of seaweed wrack at either scale. To identify potential mechanisms underlying the decrease in diversity, we fit a spatially explicit joint species distribution model to evaluate species level responses to marine subsidies and effects of biotic interactions among species. We found mixed evidence for competition for both light and nutrients, and cannot rule out an alternative mechanism; the observed decrease in species richness may be due to disturbances associated with animal-mediated nutrient deposits, particularly those from North American river otters ( Lontra canadensis ). By evaluating the scale-dependent effects of marine subsidies on island biogeographic patterns of plants and revealing likely mechanisms that act on community composition, we provide novel insights on the scale dependence of a fundamental ecological theory, and on the rarely examined links between marine and terrestrial ecosystems often bridged by animal vectors., Competing Interests: Authors declare no conflict of interest., (© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

There is a gap between lab experiments where resistivity-soil moisture relations are generally very good and field studies in complex environmental settings where relations are always less good and complicated by many factors. An experiment was designed where environmental settings are more controlled, the best outside laboratory, to assess the transferability from lab to outdoor. A field experiment was carried out to evaluate the use of electric resistivity tomography (ERT) for monitoring soil moisture dynamics over a period of 67 days. A homogeneous site in the central part of The Netherlands was selected consisting of grass pasture on an aeolian sand soil profile. ERT values were correlated to gravimetric soil moisture samples for five depths at three different dates. Correlations ranged from 0.43 to 0.73 and were best for a soil depth of 90 cm. Resistivity patterns over time (time-lapse ERT) were analyzed and related to rainfall events where rainfall infiltration patterns could be identified. Duplicate ERT measurements showed that the noise level of the instrument and measurements is low and generally below 3% for the soil profile below the mixed layer but above the groundwater. Although the majority of the measured resistivity patterns could be well explained, some artefacts and dynamics were more difficult to clarify, even so in this homogeneous field situation. The presence of an oak tree with its root structure and a ditch with surface water with higher conductivity may have an impact on the resistivity pattern in the soil profile and over time. We conclude that ERT allows for detailed spatial measurement of local soil moisture dynamics resulting from precipitation although field experiments do not yield accuracies similar to laboratory experiments. ERT approaches are suitable for detailed spatial analyses where probe or sample-based methods are limited in reach or repeatability.

Humans alter the environment at unprecedented rates through habitat destruction, nutrient pollution and the application of agrochemicals. This has recently been proposed to act as a potentially significant driver of pathogen-carrying mosquito species (disease vectors) that pose a health risk to humans and livestock. Here, we use a unique set of locations along a large geographical gradient to show that landscapes disturbed by a variety of anthropogenic stressors are consistently associated with vector-dominated mosquito communities for a wide range of human and livestock infections. This strongly suggests that human alterations to the environment promote the presence and abundance of disease vectors across large spatial extents. As such, it warrants further studies aimed at unravelling mechanisms underlying vector prevalence in mosquito communities, and opens up new opportunities for preventative action and predictive modelling of vector borne disease risks in relation to degradation of natural ecosystems.

The classical theory of island biogeography , which predicts species richness using island area and isolation, has been expanded to include contributions from marine subsidies, i.e. subsidized island biogeography (SIB) theory . We tested the effects of marine subsidies on species diversity and population density on productive temperate islands, evaluating SIB predictions previously untested at comparable scales and subsidy levels. We found that the diversity of terrestrial breeding bird communities on 91 small islands (approx. 0.0001-3 km 2 ) along the Central Coast of British Columbia, Canada were correlated most strongly with island area, but also with marine subsidies. Species richness increased and population density decreased with island area, but isolation had no measurable influence. Species richness was negatively correlated with marine subsidy, measured as forest-edge soil δ 15 N. Density, however, was higher on islands with higher marine subsidy, and a negative interaction between area and subsidy indicates that this effect is stronger on smaller islands, offering some support for SIB. Our study emphasizes how subsidies from the sea can shape diversity patterns on islands and can even exceed the importance of isolation in determining species richness and densities of terrestrial biota.

Human occupation is usually associated with degraded landscapes but 13,000 years of repeated occupation by British Columbia's coastal First Nations has had the opposite effect, enhancing temperate rainforest productivity. This is particularly the case over the last 6,000 years when intensified intertidal shellfish usage resulted in the accumulation of substantial shell middens. We show that soils at habitation sites are higher in calcium and phosphorous. Both of these are limiting factors in coastal temperate rainforests. Western redcedar (Thuja plicata) trees growing on the middens were found to be taller, have higher wood calcium, greater radial growth and exhibit less top die-back. Coastal British Columbia is the first known example of long-term intertidal resource use enhancing forest productivity and we expect this pattern to occur at archaeological sites along coastlines globally.

Anthropogenic landscape change (i.e., disturbance) is recognized as an important factor in the decline and extirpation of wildlife populations. Understanding and monitoring the relationship between wildlife distribution and disturbance is necessary for effective conservation planning. Many studies consider disturbance as a covariate explaining wildlife behavior. However, we propose that there are several advantages to considering the spatial relationship between disturbance and wildlife directly using utilization distributions (UDs), including objective assessment of the spatially explicit overlap between wildlife and disturbance, and the ability to track trends in this relationship over time. Here, we examined how central mountain woodland caribou ( Rangifer tarandus caribou ) distribution changed over time in relation to (i) anthropogenic disturbance, baseline range (defined using telemetry data from 1998 to 2005), and alpine habitat; and (ii) interannual climate variation (North Pacific Index; NPI). We developed seasonal UDs for caribou in west-central Alberta and east-central British Columbia, Canada, monitored with GPS collars between 1998 and 2013. We mapped the cumulative annual density of disturbance features within caribou range and used indices of overlap to determine the spatial relationship and trend between caribou UDs, anthropogenic disturbance, baseline range, alpine habitat, and the NPI. Anthropogenic disturbance increased over time, but the overlap between caribou UDs and disturbance did not. Caribou use of alpine habitat during spring, fall, and late winter increased over time, concurrent with a decrease in use of baseline range. Overlap between caribou UDs and disturbance increased during spring and fall following relatively cold, snowy winters (high NPI), but overall, climate did not explain changes in caribou distribution over time. We provide evidence supporting the hypothesis that caribou populations adjust their spatial distribution in relation to anthropogenic landscape change. Our findings could have implications for population persistence if distributional shifts result in greater use of alpine habitat during winter. Monitoring long-term changes in the distribution of populations is a valuable component of conservation planning for species at risk in disturbed landscapes.