Fine scale functional metacommunity dynamics: analysing the role of disturbance‐driven environmental variability in grasslands

2021 ◽  
Author(s):  
Célia Pouget ◽  
Julien Pottier ◽  
Franck Jabot
Keyword(s):  
Environmental Variability ◽  
Fine Scale ◽  
Metacommunity Dynamics

scholarly journals Ecological Connectivity in Agricultural Green Infrastructure:  Suggested Criteria for Fine Scale Assessment and Planning

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 807
Author(s):  
Simone Valeri ◽  
Laura Zavattero ◽  
Giulia Capotorti
Keyword(s):  
Land Cover ◽  
Green Infrastructure ◽  
Rural Areas ◽  
Urban Areas ◽  
Landscape Heterogeneity ◽  
Agricultural Landscapes ◽  
Spatial Pattern Analysis ◽  
Fine Scale ◽  
Unique Type

In promoting biodiversity conservation and ecosystem service capacity, landscape connectivity is considered a critical feature to counteract the negative effects of fragmentation. Under a Green Infrastructure (GI) perspective, this is especially true in rural and peri-urban areas where a high degree of connectivity may be associated with the enhancement of agriculture multifunctionality and sustainability. With respect to GI planning and connectivity assessment, the role of dispersal traits of tree species is gaining increasing attention. However, little evidence is available on how to select plant species to be primarily favored, as well as on the role of landscape heterogeneity and habitat quality in driving the dispersal success. The present work is aimed at suggesting a methodological approach for addressing these knowledge gaps, at fine scales and for peri-urban agricultural landscapes, by means of a case study in the Metropolitan City of Rome. The study area was stratified into Environmental Units, each supporting a unique type of Potential Natural Vegetation (PNV), and a multi-step procedure was designed for setting priorities aimed at enhancing connectivity. First, GI components were defined based on the selection of the target species to be supported, on a fine scale land cover mapping and on the assessment of land cover type naturalness. Second, the study area was characterized by a Morphological Spatial Pattern Analysis (MSPA) and connectivity was assessed by Number of Components (NC) and functional connectivity metrics. Third, conservation and restoration measures have been prioritized and statistically validated. Notwithstanding the recognized limits, the approach proved to be functional in the considered context and at the adopted level of detail. Therefore, it could give useful methodological hints for the requalification of transitional urban–rural areas and for the achievement of related sustainable development goals in metropolitan regions.

scholarly journals What can the occult do for you?

2016 ◽  
Vol 11 (S321) ◽  
pp. 248-250
Author(s):  
B. W. Holwerda ◽  
W. C. Keel
Keyword(s):  
Interstellar Dust ◽  
Probability Function ◽  
Great Accuracy ◽  
Extinction Curve ◽  
Clear Understanding ◽  
Fine Scale ◽  
Grain Composition ◽  
Field Unit ◽  
Integral Field

AbstractInterstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy.Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses Hubble to map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Integral Field Unit (IFU) observations will map the effective extinction curve, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy.The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: geometry, a probability function of dimming as a function of galaxy mass and radius, and its dependence on wavelength.

scholarly journals Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Environmental Variability ◽  
Time Lag ◽  
Cyanobacteria Blooms ◽  
Environment Variables ◽  
Sampling Points ◽  
The Relationship

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

Dispersal traits as benthic invertebrate assemblage drivers in a neotropical large river

2020 ◽  
Vol 193 (3) ◽  
pp. 275-283
Author(s):  
Miguel Saigo ◽  
Mercedes Marchese ◽  
Luciana Montalto
Keyword(s):  
Spatial Structure ◽  
Environmental Conditions ◽  
Distribution Patterns ◽  
Benthic Invertebrate ◽  
Large River ◽  
Species Dispersal ◽  
Dispersal Traits ◽  
Metacommunity Dynamics ◽  
Invertebrate Assemblage

Metacommunity theory is a mechanistic framework that explains the interdependence of local factors and regional processes as community drivers. Recent evidence suggests that dispersal mode is a key trait that potentially affects metacommunity dynamics. We analyzed the distribution patterns of benthic macroinvertebrates with different dispersal modes in the Middle Paraná, a neotropical large river. We assessed the relative importance of local environmental conditions and regional spatial structure as assemblage drivers. Aquatic and aerial dispersers presented Clementsian and Gleasonian structures, respectively. For both groups, local environmental conditions influenced community assembly, and spatial structure (overland distances) also affected the distribution of aerial dispersers. Our study highlights that the role of spatial structure as a driver of benthic metacommunities depends on species' dispersal modes. Aerial dispersers responded to regional spatial variables and it is likely that these organisms are also influenced by mass effects. Our results are consistent with current ideas of metacommunity dynamics in large rivers, where dispersal is not considered to limit the distribution of benthic organisms.

scholarly journals Red knots (Calidris canutus islandica) manage body mass with dieting and activity

2020 ◽  
Vol 223 (21) ◽  
pp. jeb231993
Author(s):  
Kimberley J. Mathot ◽  
Eva M. A. Kok ◽  
Piet van den Hout ◽  
Anne Dekinga ◽  
Theunis Piersma
Keyword(s):  
Food Intake ◽  
Metabolic Rate ◽  
Body Mass ◽  
Assimilation Efficiency ◽  
Adaptive Significance ◽  
Fine Scale ◽  
Calidris Canutus ◽  
Predation Danger ◽  
Mitochondrial Efficiency

ABSTRACTMass regulation in birds is well documented. For example, birds can increase body mass in response to lower availability and/or predictability of food and decrease body mass in response to increased predation danger. Birds also demonstrate an ability to maintain body mass across a range of food qualities. Although the adaptive significance of mass regulation has received a great deal of theoretical and empirical attention, the mechanisms by which birds achieve this have not. Several non-exclusive mechanisms could facilitate mass regulation in birds. Birds could regulate body mass by adjusting food intake (dieting), activity, baseline energetic requirements (basal metabolic rate), mitochondrial efficiency or assimilation efficiency. Here, we present the results of two experiments in captive red knots (Calidris canutus islandica) that assess three of these proposed mechanisms: dieting, activity and up- and down-regulation of metabolic rate. In the first experiment, knots were exposed to cues of predation risk that led them to exhibit presumably adaptive mass loss. In the second experiment, knots maintained constant body mass despite being fed alternating high- and low-quality diets. In both experiments, regulation of body mass was achieved through a combination of changes in food intake and activity. Both experiments also provide some evidence for a role of metabolic adjustments. Taken together, these two experiments demonstrate that fine-scale management of body mass in knots is achieved through multiple mechanisms acting simultaneously.

scholarly journals An investigation of the spawning behaviour of the chokka squid Loligo reynaudii and the potential effects of temperature using acoustic telemetry

2009 ◽  
Vol 67 (2) ◽  
pp. 231-243 ◽  
Author(s):  
Nicola J. Downey ◽  
Michael J. Roberts ◽  
Dan Baird
Keyword(s):  
Acoustic Telemetry ◽  
Environmental Variability ◽  
Spawning Site ◽  
Spawning Aggregations ◽  
Spawning Behaviour ◽  
Effects Of Temperature ◽  
Continuous Presence ◽  
Receiver Arrays ◽  
Spawning Sites

Abstract Downey, N. J., Roberts, M. J., and Baird, D. 2010. An investigation of the spawning behaviour of the chokka squid Loligo reynaudii and the potential effects of temperature using acoustic telemetry. – ICES Journal of Marine Science, 67: 231–243. Spawning aggregations of chokka squid are influenced by environmental conditions. Acoustic telemetry was used to monitor the behaviour of spawning squid in relation to environmental variability. During the November squid-fishery closed seasons of 2003–2006, hexagonal VR2 receiver arrays were moored on and around active spawning aggregations in Kromme Bay, South Africa. In all, 45 squid were tagged (V9P-6L-S256 transmitters) and released within these arrays. Three presence–absence behaviours were identified: (i) arrival on the spawning site at dawn and departure after dusk, (ii) continuous presence for a number of days, and (iii) presence interrupted by frequent but short periods of absence. Movement between spawning sites was both diurnal and nocturnal. Squid presence at the monitored sites increased after dawn and decreased towards and after dusk. Occasionally, a core aggregation of squid remained on the spawning sites at night. Temperature data at the sites indicated occasional upwelling, and although the role of temperature in the spawning process is not well understood, data suggest that it is linked to the continuation and or interruption of spawning after an aggregation has formed. The initial formation of spawning aggregations appears to be triggered by upwelling events.

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