scholarly journals The influence of a new water infrastructure development on the relative abundance of two Australian freshwater turtle species

2018 ◽  
Vol 66 (1) ◽  
pp. 57 ◽  
Author(s):  
Natalie J. Clark ◽  
Courtenay E. Mills ◽  
Nicolette A. Osborne ◽  
Kerry M. Neil
Keyword(s):  
Relative Abundance ◽  
Temporal Variability ◽  
Monitoring Program ◽  
Freshwater Turtle ◽  
Spatial And Temporal Variability ◽  
Main Body ◽  
Water Infrastructure ◽  
Turtle Species ◽  
Australian Freshwater ◽  
The Impact

Development of water infrastructure benefits water security and agriculture but poses risks to habitat and aquatic fauna. Wyaralong Dam was constructed on Teviot Brook in 2010 to provide future urban water supplies for South East Queensland, Australia. Construction of the dam created a large impoundment area and environmental impact assessment predicted significant impacts upon resident freshwater turtle species and their habitats. Differences in habitat requirements, life-history characteristics and sensitivity to change between the Macquarie River turtle (Emydura macquarii macquarii) and the common saw-shelled turtle (Myuchelys latisternum) were expected to influence the impact of the dam on the spatial and temporal abundance of these species. The relative abundance of each species was monitored at sites located within, upstream and downstream of the impoundment across wet and dry seasons during the dam’s first five years of operation. The results of this monitoring program indicate that spatial and temporal variability in the relative abundance of E. macquarii macquarii and M. latisternum occurred during the study but not all expected impacts were realised. Contrary to expectation, the relative abundance of E. macquarii macquarii did not increase over time within, upstream or downstream of the dam. M. latisternum showed greater temporal variability at some sites; however, no clear relationship between relative abundance and operational years was observed during the monitoring program. Spatial variability in relative abundance between sites was dependent upon season, with trends generally consistent across both turtle species. Where differences between species were observed, these are suspected to have resulted from the influence of environmental conditions on species-specific movement behaviours. The monitoring program confirmed the use of the upper limits of the impoundment and the plunge pool below the dam wall by both turtle species but relative abundance within the main body of the impoundment remained low throughout monitoring. The results of the study allow for consideration of the suitability of predefined management measures and the development of recommendations for future monitoring programs prescribed for water infrastructure developments.

scholarly journals The influence of riparian woodland on the spatial and temporal variability of stream water temperatures in an upland salmon stream

2004 ◽  
Vol 8 (3) ◽  
pp. 449-459 ◽  
Author(s):  
I. A. Malcolm ◽  
D. M. Hannah ◽  
M. J. Donaghy ◽  
C. Soulsby ◽  
A. F. Youngson
Keyword(s):  
Thermal Regime ◽  
Temporal Variability ◽  
Heat Budget ◽  
Riparian Forest ◽  
Stream Water ◽  
Spatial And Temporal Variability ◽  
Substantial Impact ◽  
Site Specific ◽  
The Impact ◽  
Riparian Woodland

Abstract. The spatio-temporal variability of stream water temperatures was investigated at six locations on the Girnock Burn (30km2 catchment), Cairngorms, Scotland over three hydrological years between 1998 and 2002. The key site-specific factors affecting the hydrology and climatology of the sampling points were investigated as a basis for physical process inference. Particular emphasis was placed on assessing the effects of riparian forest in the lower catchment versus the heather moorland riparian zones that are spatially dominant in the upper catchment. The findings were related to river heat budget studies that provided process detail. Gross changes in stream temperature were affected by the annual cycle of incoming solar radiation and seasonal changes in hydrological and climatological conditions. Inter-annual variation in these controlling variables resulted in inter-annual variability in thermal regime. However, more subtle inter-site differences reflected the impact of site-specific characteristics on various components of the river energy budget. Inter-site variability was most apparent at shorter time scales, during the summer months and for higher stream temperatures. Riparian woodland in the lower catchment had a substantial impact on thermal regime, reducing diel variability (over a period of 24 hours) and temperature extremes. Observed inter-site differences are likely to have a substantial effect on freshwater ecology in general and salmonid fish in particular. Keywords: temperature, thermal regime, forest, salmon, hydrology, Girnock Burn, Cairngorm

scholarly journals Approaches to evaluate spatial and temporal variability of deep marine sediment characteristics under the impact of dense water formation events

2020 ◽  
Author(s):  
XAVIER DURRIEU de MADRON ◽  
MARION STABHOLZ ◽  
LARS-ERIC HEIMBÜRGER-BOAVIDA ◽  
DOMINIQUE AUBERT ◽  
PHILIPPE KERHERVÉ ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Temporal Variability ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Geochemical Composition ◽  
Dense Water ◽  
Water Formation ◽  
Dense Water Formation ◽  
Northwestern Mediterranean Sea ◽  
The Impact

Dense shelf water cascading and open-ocean convection frequently occurs in the Gulf of Lions, northwestern Mediterranean Sea. These intense dense water formation events are capable of supplying large amounts of particulate matter as well as remobilizing and dispersing local sediments and, therefore, are thought to leave an imprint on superficial deposits. Here, we compared the spatial variability of the superficial sediment composition (grain size, organic parameters, and metals) at different scales (from decimetric to kilometric) on the continental slope and rise with the temporal variability linked to the occurrence of intense dense water formation events. The spatial and temporal variability of the geochemical composition of deep sediments was assessed using multivariate and geostatistical analysis. The results indicate that, on the outer reach of the Cap de Creus Canyon, where both processes interact, no clear relation was found between the temporal variability of the superficial sediment and the deep-water formation events, and that the small-scale spatial variability of the sediment is masking the temporal variability. Measurements across the southern slope indicate the presence of a somehow distinct geochemical signature that likely results from the influence of recurrent intense, dense water formation events as well as an unabating bottom trawling activity.

scholarly journals Spatial and temporal variability of water-filled crevasse hydrologic states along the shear margins of Jakobshavn Isbrae, Greenland

2017 ◽  
Author(s):  
Casey A. Joseph ◽  
Derrick J. Lampkin
Keyword(s):  
Temporal Variability ◽  
Large Strain ◽  
Water Injection ◽  
Greenland Ice Sheet ◽  
Spatial And Temporal Variability ◽  
Strain Rates ◽  
Ice Streams ◽  
Lower Elevation ◽  
Melt Water ◽  
The Impact

Abstract. The impact of melt water injection into ice streams over the Greenland Ice Sheet is not well understood. Water-filled crevasses along the shear margins of Jakobshavn Isbræ are known to fill and drain, resulting in weakening of the shear margins due to reduced basal friction. Seasonal variability in the hydrologic dynamics of these features has not been quantified. In this work, we characterize the spatial and temporal variability in the hydrological state (filled or drained) of these water-filled crevasse systems. A fusion of multi-sensor optical satellite imagery was used to examine hydrologic states from 2000 to 2015. The monthly distribution of crevasse systems observed as water filled is unimodal with peak number of filled days during the month of July at 329 days, while May has the least at 15. Over the study period the occurrence of drainage within a given season increases. Inter-seasonal drain frequencies over these systems ranged from 0 to 5. The frequency of multi-drainage events are correlated with warmer seasons and large strain rates. Over the study period, summer temperatures averaged from −1 and 2 °C and tensile strain rates have increased to as high as ~ 1.2 s-1. Intermittent melt water input during hydrofracture drainage responsible for transporting surface water to the bed is largely facilitated by high local tensile stresses. Drainage due to fracture propagation may be increasingly modulated by ocean-induced calving dynamics for the lower elevation ponds. Water-filled crevasses could expand in extent and volume as temperatures increase resulting in regional amplification of ice mass flux into the ice stream system.

scholarly journals ANÁLISE COMPARATIVA DO REGIME HÍDRICO E TÉRMICO DE DOIS SÍTIOS EXPERIMENTAIS NO PAMPA

2016 ◽  
Vol 38 ◽  
pp. 209
Author(s):  
Cláudio Alberto Teichrieb ◽  
Pablo Eli Soares de Oliveira ◽  
Tamires Zimmer ◽  
Cristiano Maboni ◽  
Daniel Michelon dos Santos ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Thermal Conductivity ◽  
Water Content ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Natural Field ◽  
Field Extensions ◽  
Pampa Biome ◽  
The Impact

In the last 15-20 years has greatly increased research on the problem of climate change, necessitating a demand for reliable measurements of absorption and emission of carbon dioxide, methane, as well as the impact on water resources. In the biome Pampa are the largest continuous natural field extensions, requiring a monitoring of water and temperature regime on the ground. The water content of the soil has spatial and temporal variability affecting many hydrological processes and determining this is needed since the soil store and provide the water and nutrients for the plants, thus involving relationships water-soil-plant-atmosphere. In this work, we compared the water content behavior of the soil at depths of 10, 30 and 50 cm, the temperature of the soil at depths of 5, 15 and 30 cm, heat flux in soil installed 10 cm deep and the thermal conductivity was determined in two experimental sites in the Pampa biome, for the period 01.01.2015 to 06.31.2015. It was found that there are differences between the sites in the capacity to retain moisture in the soil and in the ability to store energy in the soil for the study period.

scholarly journals Impacts of dams on freshwater turtles: a global review to identify conservation solutions

2021 ◽  
Author(s):  
Andrea Barcenas-Garcia ◽  
Fernanda Michalski ◽  
William H. Morgan ◽  
Rebecca K. Smith ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Freshwater Ecosystems ◽  
Freshwater Turtle ◽  
Tropical Species ◽  
Life History Stage ◽  
Freshwater Turtles ◽  
Tropical Regions ◽  
Turtle Species ◽  
Threat Status ◽  
Dam Impacts ◽  
The Impact

Dams create many impacts on freshwater ecosystems and biodiversity. Freshwater turtles are at direct and indirect risk due to changes caused by damming including the loss of terrestrial and aquatic nesting and feeding habitats, changes to resource availability and reduced dispersal. We reviewed the global scientific literature that evaluated the impact of dams on freshwater turtles, and carried out additional searches of literature published in seventeen languages for studies evaluating actions to mitigate the impact of dams. The search produced 43 published articles documenting dam impacts on 29 freshwater turtle species from seven families (Chelidae, Chelydridae, Emydidae, Geoemydidae, Kinosternidae, Podocnemididae and Trionychidae) in 13 countries. More than a third of studies (41.9%, n = 18) focused on nine North American species of the Emydidae. Few studies were found from Europe and Asia and none from Africa. The number of studies, life-history stage studied and threat status differed significantly between temperate and tropical latitudes. Most studies were from temperate latitudes, where studies focused more on adults and less threatened species compared with tropical latitudes. Studies evaluated dam impacts as barriers and changes to water flow and quality, but no studies were found that assessed turtles and changes to land cover or mercury caused by dams. More than half of the studies (59%, n = 24) suggested actions to help mitigate dam impacts. Yet, only four studies on three temperate and one tropical species documented the effect of interventions (dam removal, flow management, artificial pond maintenance and community-based action). These findings demonstrate a lack of documented evidence evaluating dam impacts on freshwater turtles particularly in tropical regions. This lack of evidence reinforces the importance of strengthening and maintaining robust long-term studies of freshwater turtles needed to develop effective conservation actions for this group of vertebrates.

scholarly journals An Examination of Limiting Factors of Chrysemys picta bellii (Western painted turtles) in the Lower Willamette River Basin, Oregon

2021 ◽  
Author(s):  
◽  
James Holley ◽  
Keyword(s):  
River Basin ◽  
Chrysemys Picta ◽  
Limiting Factors ◽  
Freshwater Turtle ◽  
Willamette River ◽  
Turtle Species ◽  
Chrysemys Picta Bellii ◽  
Nesting Activity ◽  
Willamette River Basin ◽  
The Impact

Oregon’s two native freshwater turtle species, Chrysemys picta bellii (Western painted turtle) and Actinemys marmorata (Northwestern pond turtle), have seen significantly reduced population sizes since the founding of Portland in 1845, with estimates of up to 90% for A. marmorata. This project examined turtle nesting activity at 25 sites across a range of turtle populations and habitats around the Lower Willamette River Basin. All discovered turtle nesting activity was found in areas of high solar exposure. We found 93% of over 400 nest attempts to have been depredated across the 25 sites, well above most other reported rates. At several sites, many aborted nest attempts were found atop gravel roadbeds, indicating that lack of appropriate substrate is potentially limiting nesting success. The presence of greater than five pedestrians per hour at turtle nesting areas was correlated with a substantial decrease in nesting attempts suggesting that management of recreational activities may play a role in the amount of nesting activity occurring. Hence, site-specific solutions, such as importing substrate, alteration of path locations or seasonal trail closures to lessen human foot traffic disturbance of turtle nesting attempts, are likely to improve recruitment rates of native turtles in the Lower Willamette Basin. Further studies that improve knowledge of population demographics, the impact of human activities on turtles, and habitat needs of juvenile turtles are needed to support long-term self-sustaining turtle populations.

scholarly journals Spatial and Temporal Variability of Ice Algal Trophic Markers—With Recommendations about Their Application

2020 ◽  
Vol 8 (9) ◽  
pp. 676
Author(s):  
Eva Leu ◽  
Thomas A. Brown ◽  
Martin Graeve ◽  
Jozef Wiktor ◽  
Clara J. M. Hoppe ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Sea Ice ◽  
Temporal Variability ◽  
Climate Change Impacts ◽  
Isotope Ratios ◽  
Arctic Sea Ice ◽  
Stable Isotope Ratios ◽  
Spatial And Temporal Variability ◽  
Web Studies ◽  
The Impact

Assessing the relative importance of sea ice algal-based production is often vital for studies about climate change impacts on Arctic marine ecosystems. Several types of lipid biomarkers and stable isotope ratios are widely used for tracing sea ic-associated (sympagic) vs. pelagic particulate organic matter (POM) in marine food webs. However, there has been limited understanding about the plasticity of these compounds in space and time, which constrains the robustness of some of those approaches. Furthermore, some of the markers are compromised by not being unambiguously specific for sea ice algae, whereas others might only be produced by a small sub-group of species. We analyzed fatty acids, highly branched isoprenoids (HBIs), stable isotope ratios of particulate organic carbon (POC) (δ13C), as well as δ13C of selected fatty acid markers during an Arctic sea ice algal bloom, focusing on spatial and temporal variability. We found remarkable differences between these approaches and show that inferences about bloom characteristics might even be contradictory between markers. The impact of environmental factors as causes of this considerable variability is highlighted and explained. We emphasize that awareness and, in some cases, caution is required when using lipid and stable isotope markers as tracers in food web studies and offer recommendations for the proper application of these valuable approaches.

scholarly journals Modeling characterization of the vertical and temporal variability of environmental DNA in the mesopelagic ocean

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elizabeth Andruszkiewicz Allan ◽  
Michelle H. DiBenedetto ◽  
Andone C. Lavery ◽  
Annette F. Govindarajan ◽  
Weifeng G. Zhang
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Temporal Variability ◽  
Mechanistic Model ◽  
Temporal Distribution ◽  
Environmental Dna ◽  
Vertical Displacement ◽  
Physical Parameters ◽  
Spatial And Temporal Variability ◽  
The Impact

AbstractIncreasingly, researchers are using innovative methods to census marine life, including identification of environmental DNA (eDNA) left behind by organisms in the water column. However, little is understood about how eDNA is distributed in the ocean, given that organisms are mobile and that physical and biological processes can transport eDNA after release from a host. Particularly in the vast mesopelagic ocean where many species vertically migrate hundreds of meters diurnally, it is important to link the location at which eDNA was shed by a host organism to the location at which eDNA was collected in a water sample. Here, we present a one-dimensional mechanistic model to simulate the eDNA vertical distribution after its release and to compare the impact of key biological and physical parameters on the eDNA vertical and temporal distribution. The modeled vertical eDNA profiles allow us to quantify spatial and temporal variability in eDNA concentration and to identify the most important parameters to consider when interpreting eDNA signals. We find that the vertical displacement by advection, dispersion, and settling has limited influence on the eDNA distribution, and the depth at which eDNA is found is generally within tens of meters of the depth at which the eDNA was originally shed from the organism. Thus, using information about representative vertical migration patterns, eDNA concentration variability can be used to answer ecological questions about migrating organisms such as what depths species can be found in the daytime and nighttime and what percentage of individuals within a species diurnally migrate. These findings are critical both to advance the understanding of the vertical distribution of eDNA in the water column and to link eDNA detection to organism presence in the mesopelagic ocean as well as other aquatic environments.

Corrigendum to: Partitioning spatial and temporal variability of tropical near-shore macrobenthic assemblages affected by natural and anthropogenic disturbances

2011 ◽  
Vol 62 (7) ◽  
pp. 885
Author(s):  
P. Rodríguez-Pliego ◽  
H. A. Hernández-Arana ◽  
P.-L. Ardisson
Keyword(s):  
Temporal Variability ◽  
Temporal Analysis ◽  
Anthropogenic Disturbances ◽  
Climatic Conditions ◽  
Analytical Models ◽  
Spatial And Temporal Variability ◽  
Coastal Zones ◽  
Macrobenthic Assemblages ◽  
Near Shore ◽  
The Impact

Coastal zones throughout the world are subject to natural and anthropogenic disturbances that modify the natural assemblages. The present study determined the response of the assemblage of macrobenthic invertebrates to the presence of a pier and natural climatic variations. Two analytical models were considered; one was an asymmetric model that permitted the comparison of the sector closest to the pier (impact) with the average of the sectors located further away (controls); the other was a three-way model that enabled the three sectors within the area to be analysed. With both models, the differences were compared among the sampling periods and the scale at which the variation in the data was greatest. No differences were detected among individual sectors or between the control and impact sectors. However, significant differences were found among the four periods. The zone closest to the pier presented greater temporal variability. This relationship suggests that the pier affecting the assemblage and the impact may be increased by the climatic conditions prevalent in the zone. It is necessary to establish a broader temporal analysis and a more detailed analysis of the structure and composition of the benthic assemblage to elucidate this temporal and spatial variability.

scholarly journals Influence of landscape condition on relative abundance and body condition of two generalist freshwater turtle species

2021 ◽  
Author(s):  
Joel L. Mota ◽  
Donald J. Brown ◽  
Danielle M. Canning ◽  
Sara M. Crayton ◽  
Darien N. Lozon ◽  
...  
Keyword(s):  
Body Condition ◽  
Relative Abundance ◽  
Freshwater Turtle ◽  
Turtle Species
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