Habitat features affecting the small-scale distribution and longitudinal migration patterns of Calotriton asper in a Pre-Pyrenean population

2008 ◽  
Vol 29 (3) ◽  
pp. 371-381 ◽  
Author(s):  
Albert Montori ◽  
Gustavo Llorente ◽  
Àlex Richter-Boix
Keyword(s):  
Abiotic Factors ◽  
Movement Patterns ◽  
Small Scale ◽  
Larval Abundance ◽  
Migration Patterns ◽  
Habitat Features ◽  
Wood Debris ◽  
Stream Migration ◽  
Capture Recapture ◽  
One Year

Abstract The longitudinal movements and abiotic factors that determine the distribution of Pyrenean mountain newts (males, females, amplexus and metamorphic newts) were examined in a 1500 meters segment of a Pre-Pyrenean stream. Migration of adult newts was studied by means of capture-recapture techniques in the course of one year. Our results indicate that the mean distance the newts migrated per year was less than 50 meters and the population could be considered sedentary. No significant differences in longitudinal movement patterns between the sexes were observed, and movement patterns were more or less constant over time. Habitat variables determining newt abundance was estimated by means of a GLM. Our results indicate that the number of refugia (wood debris, stones and fissures) determines the distribution of newts. Larval abundance was correlated with stream-bed structure.

scholarly journals Epilithic community development on artificial reefs deployed along a cross-shelf environmental gradient off Paraná state, southern Brazil

2011 ◽  
Vol 59 (spe1) ◽  
pp. 43-53 ◽  
Author(s):  
Frederico Brandini ◽  
Ariel Scheffer da Silva
Keyword(s):  
Large Scale ◽  
Diversity Index ◽  
Artificial Reef ◽  
Larval Abundance ◽  
Percent Cover ◽  
Southern Brazil ◽  
Factors Affecting ◽  
Hydrographic Conditions ◽  
One Year ◽  
General Community

Concrete modules were deployed on the bottom of the 11, 18 and 30 meters isobaths along a cross-shelf hydrographic gradient off Paraná State, Southern Brazil, with the purpose of studying the colonization of sessile epilithic macroinvertebrates on artificial surfaces. After one year of submersion a total of 63 species of epilithic organisms were identified, dominated by Ostrea puelchana, Chthamalus bisinuatus, Balanus cf spongicola, Astrangia cf rathbuni, Didemnum spp, poryphers and bryozoans. Diversity index and percent cover at reef stations placed at 11, 18 and 30 meters isobaths were respectively 2.28 and 66.7%, 2.79 and 96.6% and 1.66 and 77.4%. Differences of general community structure among the three assemblages were not clearly related to the general environmental conditions at the bottom layers near the reef stations. Turbidity and larval abundance are discussed as important factors affecting colonization processes. Results indicate that depths between 15-20 meters are more suitable for the implementation of large scale artificial reef systems in the inner shelf off Paraná and, possibly, throughout the inner shelves off southern Brazil with similar hydrographic conditions.

Capture–recapture estimates of space used in streams (CRESUS) at the population scale: case study on Zingel asper (percid), a threatened species of the Rhône catchment

2004 ◽  
Vol 61 (3) ◽  
pp. 476-486 ◽  
Author(s):  
Delphine Danancher ◽  
Jacques Labonne ◽  
Roger Pradel ◽  
Philippe Gaudin
Keyword(s):  
Spatial Data ◽  
Abiotic Factors ◽  
Estimation Method ◽  
Space Use ◽  
Longitudinal Axis ◽  
Spawning Period ◽  
Data Movement ◽  
Use Patterns ◽  
Capture Recapture ◽  
Population Scale

In this study, capture–mark–recapture statistics were applied to spatial recapture histories to assess the intensity of fish restricted movements along the longitudinal axis of a river using a previously described model for survival and recruitment analysis. Adapting the stopover estimation method to spatial data, movement probabilities were then used to estimate space used at the population scale. This capture–recapture estimates of space used in streams (CRESUS) method may thus be seen as a complementary tool of classic home range methods and should be used to explore the consequence of behavioural strategies on population mechanisms. We propose a methodological example where movements and space use strategies of a Zingel asper (percid) population in the Beaume River (Ardèche, France) were directly estimated at the population scale taking account of the effects of different biotic or abiotic factors. Results showed differences in Z. asper space use patterns among sexes, periods of biological cycle (growing and spawning period), and types of mesohabitat. Downstream movements were more important during the spawning period and by the way the riffle was more intensively used.

scholarly journals Investigating the Type of Gene Action Conditioning Tolerance to Aluminum (Al) Toxicity in Tropical Maize

2019 ◽  
pp. 1-8
Author(s):  
Victoria Ndeke ◽  
Langa Tembo
Keyword(s):  
Root Length ◽  
Aluminum Toxicity ◽  
Gene Action ◽  
Abiotic Factors ◽  
Al Toxicity ◽  
High Yield ◽  
Small Scale ◽  
Tropical Maize ◽  
Maize Varieties ◽  
Small Scale Farmers

Maize is a third important cereal crop in the world after wheat and rice. In Zambia, it is an important staple crop. Its production is however hampered by both biotic and abiotic factors. Among the abiotic factors, Aluminum (Al) toxicity causes high yield losses and is directly linked to acidic soils. Application of lime can ameliorate this problem, but it is expensive for small scale farmers. Developing maize varieties that are tolerant to Al toxicity is cheaper and feasible for small scale farmers. The purpose of this research was to investigate the type of gene action conditioning tolerance to aluminum toxicity in tropical maize.  Eleven inbred lines were mated in an 8 male (4 moderately tolerant and 4 susceptible) x 3 female (resistant) North Carolina Design II. Results revealed that general combining ability (GCA) effects due to both males and females were highly significant (P≤ 0.001) for root biomass. The shoot length GCA effects due to both male and female respectively were significant (P≤ 0.01). Similarly, the GCA effects due to females and males for root length were significant, P≤ 0.01 and P≤ 0.05 respectively. The genotype CML 511 had the most desirable significant GCA effect value (1.40) for root length among the male lines while CML 538 had the most desirable significant GCA effect value (0.92) among the female lines. The baker’s ratio for root length was found to be 0.49 implying that both additive and non-additive gene action were important in conditioning aluminum toxicity tolerance in tropical maize.

Where to go when all options are terrible: Ranging behavior of sloths in central Amazonian flooded igapó forests

2021 ◽  
Author(s):  
Matheus Castro ◽  
Renann Dias-Silva ◽  
Adrian Barnett
Keyword(s):  
Home Range ◽  
Abiotic Factors ◽  
Movement Patterns ◽  
Ranging Behavior ◽  
Forage Production ◽  
Leaf Production ◽  
Main Driver ◽  
Young Leaves ◽  
Bradypus Variegatus ◽  
Seasonally Flooded

Ranging behaviors performed by animals are influenced by both biotic and abiotic factors. For herbivorous mammals, seasonality in forage production is considered to be the main driver of movement patterns. Here, we investigated the home range and movement in one of the most abundant herbivores in the Americas, and their relationship with plant phenology in an Amazon igapó - a seasonally-flooded riverine forests with strongly-pulsed leaf-production phenology. Using a combination of telemetry and phenological analysis, the study recorded movement patterns of five brown throated three toed sloths (Bradypus variegatus Schinz, 1825) over a six months period, and related these to seasonal and within-forest differences in food availability via monitoring young leaf production of 570 trees. All monitored animals were shown to be permanently resident within igapó flooded forest, maintaining their home range even during flood periods when most trees lacked leaves. We found that seasonal variation in leaf production had no effect on the extent of displacement of the sloths. Accordingly, for herbivores with low metabolism, variation in young leaves availability may not be the main driver of their ranging behavior. In addition, an arboreal habit and well-developed swimming capacity allow igapó sloths to occupy a niche ecologically inaccessible to other mammals.

Assessment of GRACE-FO Laser Ranging Interferometer measurements

2021 ◽  
Author(s):  
Athina Peidou ◽  
Felix Landerer ◽  
David Wiese ◽  
Matthias Ellmer ◽  
Eugene Fahnestock ◽  
...  
Keyword(s):  
High Frequency ◽  
Signal To Noise Ratio ◽  
Small Scale ◽  
Laser Ranging ◽  
High Signal ◽  
Measurement Sensitivity ◽  
One Year ◽  
Mass Transfers ◽  
Gravity Recovery ◽  
System Errors

<p>The performance of Gravity Recovery and Climate Experiment Follow‐On (GRACE-FO) laser ranging interferometer (LRI) system is assessed in both space and frequency domains. With LRI’s measurement sensitivity being as small as 0.05 nm/s<sup>2</sup> at GRACE-FO altitude we perform a thorough assessment on the ability of the instrument to detect real small-scale high-frequency gravity signals. Analysis of range acceleration measurements along the orbit for nearly one year of daily solutions suggests that LRI can detect signals induced by mass perturbation up to 26 mHz, i.e., ~145 km spatial resolution. Additionally, high frequency signals that are not adequately modeled by dealiasing models are clearly detected and their magnitude is shown to reach 2-3 nm/s<sup>2</sup>. The alternative K‐band microwave ranging system (KBR) is also examined and results demonstrate the inability of KBR to retrieve signals above 15mHz (i.e., shorter than ~200 km) as the noise of the KBR range acceleration increases rapidly. Overall, the first stream of LRI measurements shows that the high signal to noise ratio allows for detection of mass transfers in finer scales, however the ability to fully exploit the high-quality signal measured by the LRI in Level 2 products is still constrained by noise of background models and other onboard instrumentation and measurement system errors.</p><p>Copyright Acknowledgment: This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Science Program.</p>

Cost-Effectiveness of Solar-Powered LED Reading Lamps in Burkina Faso

2013 ◽  
pp. 203-221
Keyword(s):  
Cost Effectiveness ◽  
Burkina Faso ◽  
Small Scale ◽  
Small Community ◽  
Reading Habits ◽  
Education Interventions ◽  
Solar Powered ◽  
Reading Test Scores ◽  
One Year ◽  
6Th Graders

A small-scale project to induce more reading among 5th and 6th graders in rural Burkina Faso by providing them with solar-powered LED lamps indeed increased reading for students in villages without preexisting libraries, but did not affect reading capabilities. The research aimed to establish the magnitude of effects after one year when 10-14 year-olds in rural African villages with small community libraries were given solar-powered lamps for night reading. The effects measured were reading habits (how much did students read?) and reading capabilities (how well could students read and comprehend what they read?). Once village effects were controlled, the lamps had statistically significant effects on reading habits for students in villages without preexisting libraries. The effect sizes were modest, ranging from .20 to .25. There were no effects on reading test scores. A cost-effectiveness metric to use for comparing with other studies of education interventions then is that expenditure of $1 per student on a solar-powered LED reading lamp distribution program generated about a 1% increase in reading, with no apparent effect on reading capabilities.

scholarly journals Testing biodiversity theory using species richness of reef-building corals across a depth gradient

2019 ◽  
Vol 15 (10) ◽  
pp. 20190493 ◽  
Author(s):  
T. Edward Roberts ◽  
Sally A. Keith ◽  
Carsten Rahbek ◽  
Tom C. L. Bridge ◽  
M. Julian Caley ◽  
...  
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Coral Species ◽  
Environmental Gradients ◽  
Abiotic Factors ◽  
Empirical Support ◽  
Null Model ◽  
Local Scale ◽  
Small Scale ◽  
Energy Availability

Natural environmental gradients encompass systematic variation in abiotic factors that can be exploited to test competing explanations of biodiversity patterns. The species–energy (SE) hypothesis attempts to explain species richness gradients as a function of energy availability. However, limited empirical support for SE is often attributed to idiosyncratic, local-scale processes distorting the underlying SE relationship. Meanwhile, studies are also often confounded by factors such as sampling biases, dispersal boundaries and unclear definitions of energy availability. Here, we used spatially structured observations of 8460 colonies of photo-symbiotic reef-building corals and a null-model to test whether energy can explain observed coral species richness over depth. Species richness was left-skewed, hump-shaped and unrelated to energy availability. While local-scale processes were evident, their influence on species richness was insufficient to reconcile observations with model predictions. Therefore, energy availability, either in isolation or in combination with local deterministic processes, was unable to explain coral species richness across depth. Our results demonstrate that local-scale processes do not necessarily explain deviations in species richness from theoretical models, and that the use of idiosyncratic small-scale factors to explain large-scale ecological patterns requires the utmost caution.

scholarly journals Diel variation of larval fish abundance in the Amazon and Rio Negro

2001 ◽  
Vol 61 (3) ◽  
pp. 357-362 ◽  
Author(s):  
C. A. R. M. ARAUJO-LIMA ◽  
V. V. da SILVA ◽  
P. PETRY ◽  
E. C. OLIVEIRA ◽  
S. M. L. MOURA
Keyword(s):  
Larval Fish ◽  
Fish Abundance ◽  
Large Rivers ◽  
Larval Abundance ◽  
Diel Variation ◽  
Larval Drift ◽  
Larval Distribution ◽  
Rio Negro ◽  
One Year

Many streams and large rivers present higher ichthyoplankton densities at night. However, in some rivers this does not occur and larvae are equally abundant during the day. Larval drift diel variation is an important information for planning sampling programs for evaluating larval distribution and production. The aim of this study was to test whether the abundance of larval fish was different at either period. We tested it by comparing day and night densities of characiform, clupeiform and siluriform larvae during five years in the Amazon and one year in Rio Negro. We found that larvae of three species of characiform and larvae of siluriform were equally abundant during day and night in the Amazon. Conversely, the catch of Pellona spp. larvae was significantly higher during the day. In Rio Negro, however, larval abundance was higher during the night. These results imply that day samplings estimate adequately the abundance of these characiform and siluriform larvae in the Amazon, but not Pellona larvae. Evaluations of larved densities of Rio Negro will have to consider night sampling.

On the locomotion of ascidian tadpole larvae

1992 ◽  
Vol 72 (1) ◽  
pp. 161-186 ◽  
Author(s):  
Q. Bone
Keyword(s):  
Gap Junctions ◽  
Electrical Activity ◽  
Movement Patterns ◽  
Muscle Cells ◽  
Small Scale ◽  
Number Range ◽  
Dorsal Muscle ◽  
Reynold’S Number ◽  
Ventral Muscle ◽  
40 Hz

This paper describes the locomotor movements of the tadpole larvae of the ascidians Ciona and Dcndrodoa and the associated electrical activity of the caudal muscle cells. Although very different in size and trunk shape, both larvae show essentially the same two movement patterns; symmetrical swimming and asymmetrical tail flicks. Swimming movements at tailbeat frequencies up to 40 Hz and forward speeds up to 10 L s (in the Reynold's number range 5·25) involve large lateral movements of the tail, and large yaw of the trunk. Tail oscillations are produced by muscle cells arranged in three segmented rows along the tail, coupled by gap junctions. Swimming is driven by axons innervating anterior ventral muscle cells. The second type of movement, single or multiple tail flicks, is driven by axons innervating dorsal muscle cells, all of which are innervated along the length of the tail. The middle row of muscle cells is not innervated. This small scale oscillatory swimming system is compared with those of chordates and larvacean tunicates, and it is concluded that both of these are very different from that of the ascidian tadpole.

Designing, Setting Up, and Facilitating a Knowledge Sharing Virtual Community of Practice, between Social Work Lecturers in the UK and India

2012 ◽  
Vol 8 (4) ◽  
pp. 22-49 ◽  
Author(s):  
Isabel Williams
Keyword(s):  
Social Work ◽  
Action Research ◽  
Knowledge Sharing ◽  
Community Of Practice ◽  
Virtual Community ◽  
Online Discussions ◽  
Small Scale ◽  
Virtual Community Of Practice ◽  
One Year ◽  
The Uk

The purpose of this research is to evaluate the effectiveness of a virtual Community of Practice (vCoP) which was developed between social work lecturers in two University settings – one in the UK and the other in India. The design and methodology draws on qualitative data collected from online discussions and semi-structured questionnaires arising from the involvement of twelve participants over a one year period. An Action Research method was adopted which allowed the shift of power from the designer to the participants over the year. This paper illustrates how a vCoP can be an ideal tool to aid communication and knowledge sharing between universities within an international context. It adds value by increasing the knowledge of participant lecturers to more than local perspectives and gives a greater understanding of social work from an international, cross-country, perspective. Although one of the limitations is that this is a small scale study, it does raise important considerations necessary for ensuring the success for vCoP’s and offers a model to aid successful online collaboration as well as important messages for those who are developing online courses and teaching within an international environment. It further gives insight into adopting Action Research as a research methodology that can be usefully used for online collaborative research.

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