Spatial Heterogeneity of eDNA Transport Improves Stream Assessment of Threatened Salmon Presence, Abundance, and Location

The integration of environmental DNA (eDNA) within management strategies for lotic organisms requires translating eDNA detection and quantification data into inferences of the locations and abundances of target species. Understanding how eDNA is distributed in space and time within the complex environments of rivers and streams is a major factor in achieving this translation. Here we study bidimensional eDNA signals in streams to predict the position and abundance of Atlantic salmon (Salmo salar) juveniles. We use data from sentinel cages with a range of abundances (3–63 juveniles) that were deployed in three coastal streams in New Brunswick, Canada. We evaluate the spatial patterns of eDNA dispersal and determine the effect of discharge on the dilution rate of eDNA. Our results show that eDNA exhibits predictable plume dynamics downstream from sources, with eDNA being initially concentrated and transported in the midstream, but eventually accumulating in stream margins with time and distance. From these findings we developed a fish detection and distribution prediction model based on the eDNA ratio in midstream versus bankside sites for a variety of fish distribution scenarios. Finally, we advise that sampling midstream at every 400 m is sufficient to detect a single fish at low velocity, but sampling efforts need to be increased at higher water velocity (every 100 m in the systems surveyed in this study). Studying salmon eDNA spatio-temporal patterns in lotic environments is essential to developing strong quantitative population assessment models that successfully leverage eDNA as a tool to protect salmon populations.

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Fine-scale structures as spots of increased fish concentration in the open ocean

Scientific Reports ◽

10.1038/s41598-021-94368-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alberto Baudena ◽

Enrico Ser-Giacomi ◽

Donatella D’Onofrio ◽

Xavier Capet ◽

Cedric Cotté ◽

...

Keyword(s):

Coherent Structures ◽

Trophic Levels ◽

Fish Distribution ◽

Lagrangian Coherent Structures ◽

Mesopelagic Fish ◽

Fine Scale ◽

Conservation Policies ◽

Top Predators ◽

Frontal Zones ◽

Spatio Temporal

AbstractOceanic frontal zones have been shown to deeply influence the distribution of primary producers and, at the other extreme of the trophic web, top predators. However, the relationship between these structures and intermediate trophic levels is much more obscure. In this paper we address this knowledge gap by comparing acoustic measurements of mesopelagic fish concentrations to satellite-derived fine-scale Lagrangian Coherent Structures in the Indian sector of the Southern Ocean. First, we demonstrate that higher fish concentrations occur more frequently in correspondence with strong Lagrangian Coherent Structures. Secondly, we illustrate that, while increased fish densities are more likely to be observed over these structures, the presence of a fine-scale feature does not imply a concomitant fish accumulation, as other factors affect fish distribution. Thirdly, we show that, when only chlorophyll-rich waters are considered, front intensity modulates significantly more the local fish concentration. Finally, we discuss a model representing fish movement along Lagrangian features, specifically built for mid-trophic levels. Its results, obtained with realistic parameters, are qualitatively consistent with the observations and the spatio-temporal scales analysed. Overall, these findings may help to integrate intermediate trophic levels in trophic models, which can ultimately support management and conservation policies.

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Environmental DNA as a ‘Snapshot’ of Fish Distribution: A Case Study of Japanese Jack Mackerel in Maizuru Bay, Sea of Japan

PLoS ONE ◽

10.1371/journal.pone.0149786 ◽

2016 ◽

Vol 11 (3) ◽

pp. e0149786 ◽

Cited By ~ 92

Author(s):

Satoshi Yamamoto ◽

Kenji Minami ◽

Keiichi Fukaya ◽

Kohji Takahashi ◽

Hideki Sawada ◽

...

Keyword(s):

Sea Of Japan ◽

Environmental Dna ◽

Fish Distribution ◽

Jack Mackerel ◽

Japanese Jack Mackerel

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Effect of background clutter on neural discrimination in the bat auditory midbrain

Journal of Neurophysiology ◽

10.1152/jn.00109.2021 ◽

2021 ◽

Author(s):

Kathryne M Allen ◽

Angeles Salles ◽

Sanwook Park ◽

Mounya Elhilali ◽

Cynthia F. Moss

Keyword(s):

Acoustic Scattering ◽

Object Discrimination ◽

Complex Environments ◽

Acoustic Features ◽

Temporal Separation ◽

Complex Sounds ◽

Electrophysiological Recordings ◽

Background Clutter ◽

Spatio Temporal ◽

Neural Underpinnings

The discrimination of complex sounds is a fundamental function of the auditory system. This operation must be robust in the presence of noise and acoustic clutter. Echolocating bats are auditory specialists that discriminate sonar objects in acoustically complex environments. Bats produce brief signals, interrupted by periods of silence, rendering echo snapshots of sonar objects. Sonar object discrimination requires that bats process spatially and temporally overlapping echoes to make split-second decisions. The mechanisms that enable this discrimination are not well understood, particularly in complex environments. We explored the neural underpinnings of sonar object discrimination in the presence of acoustic scattering caused by physical clutter. We performed electrophysiological recordings in the inferior colliculus of awake big brown bats, to broadcasts of pre-recorded echoes from physical objects. We acquired single unit responses to echoes and discovered a sub-population of IC neurons that encode acoustic features that can be used to discriminate between sonar objects. We further investigated the effects of environmental clutter on this population's encoding of acoustic features. We discovered that the effect of background clutter on sonar object discrimination is highly variable and depends on object properties and target-clutter spatio-temporal separation. In many conditions, clutter impaired discrimination of sonar objects. However, in some instances clutter enhanced acoustic features of echo returns, enabling higher levels of discrimination. This finding suggests that environmental clutter may augment acoustic cues used for sonar target discrimination and provides further evidence in a growing body of literature that noise is not universally detrimental to sensory encoding.

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Extent and Variation of Nitrogen Losses from Non-legume Field Crops of Conterminous United States

Nitrogen ◽

10.3390/nitrogen1010005 ◽

2020 ◽

Vol 1 (1) ◽

pp. 34-51

Author(s):

Amitava Chatterjee

Keyword(s):

United States ◽

Management Strategies ◽

Application Rate ◽

Fertilizer N ◽

N Loss ◽

N Losses ◽

Field Crops ◽

N Application Rate ◽

Spatio Temporal ◽

N Management

Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN2O), ammonia volatilization (CNH3), and nitrate leaching (CNO3−) during the growing season and associated crop, soil, and water management information were gathered to determine the extent and controls of these losses. This database consisted of 404, 26, and 358 observations of CN2O, CNH3, and CNO3− losses, respectively, from sixty-two peer-reviewed manuscripts. Corn (Zea mays) dominated the N loss studies. Losses ranged between −0.04 to 16.9, 2.50 to 50.9, and 0 to 257 kg N ha−1 for CN2O, CNH3 and CNO3−, respectively. Most CN2O and CNO3− observations were reported from Colorado (n = 100) and Iowa (n = 176), respectively. The highest values of CN2O, and CNO3− were reported from Illinois and Minnesota states, and corn and potato (Solanum tuberosum), respectively. The application of anhydrous NH3 had the highest value of CN2O loss, and ammonium nitrate had the highest CNO3− loss. Among the different placement methods, the injection of fertilizer-N had the highest CN2O loss, whereas the banding of fertilizer-N had the highest CNO3− loss. The maximum CNO3− loss was higher for chisel than no-tillage practice. Both CN2O and CNO3− were positively correlated with fertilizer N application rate and the amount of water input (irrigation and rainfall). Fertilizer-N management strategies to control N loss should consider the spatio-temporal variability of interactions among climate, crop-and soil types.

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Modeling Environmental Impacts on Viticultural Ecosystems

International Journal of Agricultural and Environmental Information Systems ◽

10.4018/ijaeis.2017070101 ◽

2017 ◽

Vol 8 (3) ◽

pp. 1-20

Author(s):

Cyril Tissot ◽

Etienne Neethling ◽

Mathias Rouan ◽

Gérard Barbeau ◽

Hervé Quénol ◽

...

Keyword(s):

Environmental Impacts ◽

Environmental Conditions ◽

Management Strategies ◽

Temporal Data ◽

Agent Based ◽

Knowledge Database ◽

Behavioral Dynamics ◽

Regulatory Data ◽

Temporal Data Models ◽

Spatio Temporal

This paper focuses on simulating environmental impacts on grapevine behavioral dynamics and vineyard management strategies. The methodology presented uses technology from geomatics object oriented databases and spatio-temporal data models. Our approach has two principle objectives, first, to simulate grapevine phenology and grape ripening under spatial and temporal environmental conditions and constraints and secondly, to simulate viticultural practices and adaptation strategies under various constraints (environmental, economical, socio-technical). The approach is based on a responsive agent-based structure where environmental conditions and constraints are considered as a set of forcing data (biophysical, socio-economic and regulatory data) that influences the modelled activities. The experiment was conducted in the regulated wine producing appellation Grand Cru “Quarts de Chaume”, situated in the middle Loire Valley, France. All of the methodology, from the implementation of the knowledge database to the analysis of the first simulation, is presented in this paper.

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Recent research on landslide dams - a literature review with special attention to New Zealand

Progress in Physical Geography Earth and Environment ◽

10.1191/0309133302pp333ra ◽

2002 ◽

Vol 26 (2) ◽

pp. 206-235 ◽

Cited By ~ 133

Author(s):

Oliver Korup

Keyword(s):

New Zealand ◽

Management Strategies ◽

Temporal Distribution ◽

Landslide Dam ◽

Distribution Patterns ◽

Future Research ◽

Case Examples ◽

Mountainous Regions ◽

Landslide Dams ◽

Spatio Temporal

More than a decade has passed since the publication of the benchmark paper of Costa and Schuster (Costa, J.E. and Schuster, R.L. 1988: The formation and failure of natural dams. Geological Society of America Bulletin 100, 1054-68) on the formation and failure of natural dams. This review takes a critical look at recent trends and developments in international and New Zealand-based research on landslide dams. Temporary or permanent stream blockages by mass movements commonly occur in steep terrain, and gradually receive more attention and awareness with increasing population and land use pressure in upland regions. Different approaches in methodology and their relevance and application potential for engineering and mitigative measures are reviewed and several shortcomings outlined, with a view towards possible future research directions. A high percentage of previous work on landslide dams has been mainly descriptive in character, and has produced a multitude of documented case studies. Recent attempts to redress the balance have included the establishment of global and nationwide databases (inventories) of landslide dams, progress in predictive, quantitative and GIS-based modelling. Furthermore, interpretative approaches towards the reconstruction of former stream blockages and their spatio-temporal distribution patterns have been pursued, which may assist assessments of present and future geomorphic hazards. Both such appraisals as well as management strategies in mountainous regions in general, will have to rely on key data efficiently extracted from a plethora of case examples. Further work includes consideration of temporal and permanent landslide-triggered stream impoundments within Quaternary landscape evolution, quantification of sediment budgets and palaeoenvironmental reconstruction. Overall, there is still a considerable lack of understanding of geomorphic forms and processes involved with landslide-dam formation, stability and failure, part of which is inherent in the often ephemeral nature of stream blockages in coupled hillslope-valley systems.

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Spatio-temporal patterns of multi-trophic biodiversity and food-web characteristics across a river catchment

10.1101/2021.07.20.450136 ◽

2021 ◽

Author(s):

Rosetta C Blackman ◽

Hsi-Cheng Ho ◽

Jean-Claude Walser ◽

Florian Altermatt

Keyword(s):

Food Web ◽

Environmental Dna ◽

Ecological Communities ◽

Food Web Structure ◽

Spatial And Temporal Scales ◽

Natural Systems ◽

Α Diversity ◽

Link Density ◽

Spatio Temporal ◽

Taxonomic Groups

Accurate characterisation of ecological communities with respect to their biodiversity and food-web structure is essential for conservation. However, combined empirical study of biodiversity and multi-trophic food webs at a large spatial and temporal resolution has been prohibited by the lack of appropriate access to such data from natural systems. Here, we assessed biodiversity and food-web characteristics across a 700 km2 riverine network through time using environmental DNA. We find contrasting biodiversity patterns, with richness (α-diversity) of fish increasing towards downstream positions within the catchment, while freshwater bacteria and invertebrates having an invariant and minimal decrease in richness, respectively, with downstream position. Food-web characteristics, such as link density and nestedness, however, were relatively conserved across space, but varied over season. Patterns of biodiversity across major taxonomic groups are thus not directly scalable to food-web structures at the same spatial and temporal scales, indicating that effective conservation measures must consider them jointly.

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Mapping lichen changes in the summer range of the George River Caribou Herd (Québec-Labrador, Canada) using Landsat imagery (1976-1998)

Rangifer ◽

10.7557/2.24.1.299 ◽

2004 ◽

Vol 24 (1) ◽

pp. 31-50 ◽

Cited By ~ 4

Author(s):

Jérôme Théau ◽

Claude R. Duguay

Keyword(s):

Remote Sensing ◽

Habitat Degradation ◽

Landsat Imagery ◽

Management Strategies ◽

Distribution Patterns ◽

Landsat Images ◽

Lichen Cover ◽

Summer Range ◽

Spatio Temporal ◽

George River

Habitat studies are essential in order to understand the dynamics of migratory caribou herds and to better define management strategies. In this paper, multi-date Landsat images are used to map lichen in the summer range of the George River Caribou Herd (GRCH), Québec-Labrador (Canada), over the period from 1976 to 1998. Multi-Spectral Scanner scenes from the seventies and Thematic Mapper scenes from the eighties and nineties were radiometrically normalized and processed using spectral mixture analysis to produce lichen fraction maps and lichen change maps. Field sites, surveyed during summer campaigns in 2000 and 2001, are used to validate the lichen maps. Results show a good agreement between field data and the lichen results obtained from image analysis. Maps are then interpreted in the context of previous caribou dynamics and habitat studies conducted in the study area over the last three decades. The remote-sensing results confirm the habitat degradation and herd distribution patterns described by other investigators. The period between 1976-1979 and 1985-1986 is characterized by a localized decrease in lichen cover in the southern part of the study area, whereas from 1985-1986 to 1998 the decrease in lichen cover extends northward and westward. This period coincides with the widest extent of the GRCH summer range and activity. The approach presented in this paper provides a valuable means for better understanding the spatio-temporal relation between herd dynamics and distribution, as well as habitat use. Satellite remote sensing imagery is a useful data source, providing timely information over vast and remote territories where caribou populations cannot be surveyed and managed on a frequent basis.

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Analysis of Non-Parametric Trend and Climatic Parameter Homogeneity Tests in a Data-scarce Region: A Spatio-Temporal Perspective in the Tawang River Basin, Eastern Himalayas

10.21203/rs.3.rs-1107455/v1 ◽

2021 ◽

Author(s):

Juna Probha Devi ◽

Chandan Mahanta ◽

Anamika Barua

Keyword(s):

Water Resource Management ◽

Management Strategies ◽

Kendall Test ◽

Climate Impact ◽

Mean Annual Precipitation ◽

Homogeneity Test ◽

Eastern Region ◽

Positive Trend ◽

Temporal Perspective ◽

Spatio Temporal

Abstract This study is aimed at studying long–term historical and future (1950-2099) trends for the RCP 4.5 and RCP 8.5 on approximately 30-year timescale at annual and seasonal for precipitation and at annual, seasonal, monthly, and diurnal temperature range (DTR) for temperature maximum (T_max), temperature minimum (T_min) variations using statistical trend analysis techniques– Mann–Kendall test (MK) and Sen's slope estimator (S) and the homogeneity test using Pettitt’s test. The study is carried out in three spatial points across the Tawang Chu in the district of Tawang, Arunachal Pradesh. The summer mean precipitation for RCP 4.5 (2006-2065) shows a positive trend with a rise in precipitation between 1.56 mm to 9.94 mm in all the study points. The mean annual precipitation statistics for all the points show an increase of RCP 4.5 in 2006-2052 and 2053-2099 timescale. Both RCP 4.5 and 8.5 scenarios exhibit a uniform rise in T_min and T_max during investigation. For all the points, the results likewise reveal a rising trend in mean annual T_min and T_max. Still, the inter-decadal temperature statistical analysis shows that the increase in mean annual T_min is greater than the increase in T_max, indicating a decreasing trend in DTR. It is anticipated that this study's outcomes will contribute to a better understanding of the relationship between change in climate and the regional hydrological behaviour and will be benefitting the society to develop a regional strategy for water resource management, can serve as a resource for climate impact research scope- assessments, adaptation, mitigation, and disaster management strategies for India's north-eastern region.

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Hydrogeomorphology as a Tool in the Evolutionary Analysis of the Dynamic Landscape—Application to Larrodrigo, Salamanca, Spain

Land ◽

10.3390/land10121407 ◽

2021 ◽

Vol 10 (12) ◽

pp. 1407

Author(s):

Lorena Lombana ◽

Antonio Martínez-Graña ◽

Marco Criado ◽

Carlos Palacios

Keyword(s):

Remote Sensing ◽

Management Strategies ◽

Evolutionary Analysis ◽

Surface Data ◽

Dynamic Landscape ◽

Density Surface ◽

Fluvial Landscape ◽

Spatio Temporal ◽

Remote Sensing Techniques ◽

Definition Of

Evolutionary analysis of the fluvial landscape provides relevant inputs for the environmental management of a territory, in such a way that the understanding of the dynamics of fluvial spaces becomes a preponderant factor in the definition of protection and management strategies. Although the development of geographic information systems is a step forward in the study of the landscape, it is necessary to establish methodological frameworks that make remote sensing techniques available at multiple spatio-temporal scales, especially in basins with high levels of intervention. In the present study, we develop a methodology for the analysis of the fluvial landscape development in the last century of a highly modified water body, through the detailed study of hydrogeomorphic elements, using remote sensing techniques including high-density surface data (LiDAR) and historical aerial imageries; when supported by fieldwork, these allow for the identification of the sequence of sedimentation–erosion zones, differentiating in detail the zones denominated as areas of current erosion, accretion zones, and historical erosion zones. An application of the methodology was carried out in the Larrodrigo stream, located in Salamanca, Spain.

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