Generalizations of the Moran Effect Explaining Spatial Synchrony in Population Fluctuations

2005 ◽  
Vol 166 (5) ◽  
pp. 603
Author(s):  
Engen ◽  
Sæther
Keyword(s):  
Population Fluctuations ◽  
Moran Effect ◽  
Spatial Synchrony

Synchrony in larval yellow perch abundance: the influence of the Moran Effect during early life history

2016 ◽  
Vol 73 (10) ◽  
pp. 1567-1574 ◽  
Author(s):  
Daniel J. Dembkowski ◽  
David W. Willis ◽  
Melissa R. Wuellner
Keyword(s):  
Yellow Perch ◽  
Spatial Scales ◽  
Population Characteristics ◽  
Freshwater Species ◽  
Population Fluctuations ◽  
Moran Effect ◽  
Spatial Synchrony ◽  
Geographic Scale ◽  
Data Set ◽  
Spatiotemporal Trends

Recruitment may vary substantially in fish populations, which can drive not only adult population characteristics but also the dynamics of fishes dependent on the species of interest and recreational fisheries for these species. However, spatiotemporal trends in population fluctuations and potential drivers of recruitment variability are poorly understood. Therefore, we used a long-term (2000–2014) data set to estimate the extent of spatial synchrony in larval abundance and factors influencing variability in recruitment of yellow perch (Perca flavescens). Contrary to the prevailing paradigm that spatial synchrony in population fluctuations (i.e., recruitment) is typically absent or occurs at small spatial scales (<50 km) for freshwater species, abundance of larval yellow perch was synchronous among spatially segregated systems across a geographic scale of at least 180 km. Additionally, variation in larval yellow perch density was influenced by spatially-correlated climatic and hydrological variables (indicative of the Moran Effect). Results ultimately broaden the scale at which factors were previously thought to influence recruitment of freshwater fishes and provide important insight to patterns and processes that structure yellow perch populations.

scholarly journals Phase-dependent outbreak dynamics of geometrid moth linked to host plant phenology

2009 ◽  
Vol 276 (1676) ◽  
pp. 4119-4128 ◽  
Author(s):  
Jane U. Jepsen ◽  
Snorre B. Hagen ◽  
Stein-Rune Karlsen ◽  
Rolf A. Ims
Keyword(s):  
Host Plant ◽  
Large Scale ◽  
Spatial Dynamics ◽  
Growing Season ◽  
Birch Forest ◽  
Moran Effect ◽  
Spatial Synchrony ◽  
Spring Phenology ◽  
Growth And Survival ◽  
Spread Model

Climatically driven Moran effects have often been invoked as the most likely cause of regionally synchronized outbreaks of insect herbivores without identifying the exact mechanism. However, the degree of match between host plant and larval phenology is crucial for the growth and survival of many spring-feeding pest insects, suggesting that a phenological match/mismatch-driven Moran effect may act as a synchronizing agent. We analyse the phase-dependent spatial dynamics of defoliation caused by cyclically outbreaking geometrid moths in northern boreal birch forest in Fennoscandia through the most recent massive outbreak (2000–2008). We use satellite-derived time series of the prevalence of moth defoliation and the onset of the growing season for the entire region to investigate the link between the patterns of defoliation and outbreak spread. In addition, we examine whether a phase-dependent coherence in the pattern of spatial synchrony exists between defoliation and onset of the growing season, in order to evaluate if the degree of matching phenology between the moth and their host plant could be the mechanism behind a Moran effect. The strength of regional spatial synchrony in defoliation and the pattern of defoliation spread were both highly phase-dependent. The incipient phase of the outbreak was characterized by high regional synchrony in defoliation and long spread distances, compared with the epidemic and crash phase. Defoliation spread was best described using a two-scale stratified spread model, suggesting that defoliation spread is governed by two processes operating at different spatial scale. The pattern of phase-dependent spatial synchrony was coherent in both defoliation and onset of the growing season. This suggests that the timing of spring phenology plays a role in the large-scale synchronization of birch forest moth outbreaks.

scholarly journals Spatial synchrony of a highly endemic fish Assemblage (Segredo Reservoir, Iguaçu River, Paraná State, Brazil)

2005 ◽  
Vol 65 (3) ◽  
pp. 439-449 ◽  
Author(s):  
W. M. Domingues ◽  
L. M. Bini ◽  
A. A. Agostinho
Keyword(s):  
Fish Assemblage ◽  
Mantel Test ◽  
Environmental Stochasticity ◽  
Population Fluctuations ◽  
Spatial Synchrony ◽  
Population Synchrony ◽  
Plausible Hypothesis ◽  
Geographical Distances ◽  
Endemic Fish ◽  
Iguaçu River

In this study, patterns of spatial synchrony in population fluctuations (cross-correlation) of an endemic fish assemblage of a Neotropical reservoir (Segredo Reservoir, Iguaçu River, Paraná State, Brazil) were reported. First, the level of population synchrony for 20 species was estimated. Second, population synchrony was correlated, using the Mantel test, with geographical distances among sites (n = 11) and also environmental synchrony (temperature). Nine species presented significant correlations between spatial synchrony and geographic distances (Astyanax sp. b, Astyanax sp. c, Pimelodus sp., Hoplias malabaricus, Crenicichla iguassuensis, Hypostomus derbyi, Hypostomus myersi, Rhamdia branneri, and R. voulezi). Considering the ecology of the species and the significant relationship between population and environmental synchronies, it seems that environmental stochasticity is the most plausible hypothesis in explaining the observed synchrony patterns.

scholarly journals Geographical variation in the spatial synchrony of a forest-defoliating insect: isolation of environmental and spatial drivers

2013 ◽  
Vol 280 (1753) ◽  
pp. 20122373 ◽  
Author(s):  
Kyle J. Haynes ◽  
Ottar N. Bjørnstad ◽  
Andrew J. Allstadt ◽  
Andrew M. Liebhold
Keyword(s):  
Gypsy Moth ◽  
Forest Type ◽  
Weather Conditions ◽  
Spatial Proximity ◽  
Generalist Predators ◽  
Population Fluctuations ◽  
Spatial Synchrony ◽  
Acorn Production ◽  
Environmental Perturbations ◽  
Underlying Mechanisms

Despite the pervasiveness of spatial synchrony of population fluctuations in virtually every taxon, it remains difficult to disentangle its underlying mechanisms, such as environmental perturbations and dispersal. We used multiple regression of distance matrices (MRMs) to statistically partition the importance of several factors potentially synchronizing the dynamics of the gypsy moth, an invasive species in North America, exhibiting outbreaks that are partially synchronized over long distances (approx. 900 km). The factors considered in the MRM were synchrony in weather conditions, spatial proximity and forest-type similarity. We found that the most likely driver of outbreak synchrony is synchronous precipitation. Proximity played no apparent role in influencing outbreak synchrony after accounting for precipitation, suggesting dispersal does not drive outbreak synchrony. Because a previous modelling study indicated weather might indirectly synchronize outbreaks through synchronization of oak masting and generalist predators that feed upon acorns, we also examined the influence of weather and proximity on synchrony of acorn production. As we found for outbreak synchrony, synchrony in oak masting increased with synchrony in precipitation, though it also increased with proximity. We conclude that precipitation could synchronize gypsy moth populations directly, as in a Moran effect, or indirectly, through effects on oak masting, generalist predators or diseases.

scholarly journals Population fluctuations and spatial synchrony in an arboreal rodent

Oecologia ◽  
2019 ◽  
Vol 191 (4) ◽  
pp. 861-871 ◽  
Author(s):  
Vesa Selonen ◽  
Jaanus Remm ◽  
Ilpo K. Hanski ◽  
Heikki Henttonen ◽  
Otso Huitu ◽  
...  
Keyword(s):  
Large Scale ◽  
Extinction Risk ◽  
Winter Precipitation ◽  
Climatic Conditions ◽  
Small Scale ◽  
Population Fluctuations ◽  
Spatial Synchrony ◽  
Flying Squirrels ◽  
Study Sites ◽  
Over Time

Abstract Climatic conditions, trophic links between species and dispersal may induce spatial synchrony in population fluctuations. Spatial synchrony increases the extinction risk of populations and, thus, it is important to understand how synchrony-inducing mechanisms affect populations already threatened by habitat loss and climate change. For many species, it is unclear how population fluctuations vary over time and space, and what factors potentially drive this variation. In this study, we focus on factors determining population fluctuations and spatial synchrony in the Siberian flying squirrel, Pteromys volans, using long-term monitoring data from 16 Finnish populations located 2–400 km apart. We found an indication of synchronous population dynamics on a large scale in flying squirrels. However, the synchrony was not found to be clearly related to distance between study sites because the populations seemed to be strongly affected by small-scale local factors. The regularity of population fluctuations varied over time. The fluctuations were linked to changes in winter precipitation, which has previously been linked to the reproductive success of flying squirrels. Food abundance (tree mast) and predator abundance were not related to population fluctuations in this study. We conclude that spatial synchrony was not unequivocally related to distance in flying squirrels, as has been observed in earlier studies for more abundant rodent species. Our study also emphasises the role of climate in population fluctuations and the synchrony of the species.

Synchrony in population dynamics of juvenile Atlantic salmon: analyzing spatio-temporal variation and the influence of river flow and demography

2021 ◽  
Author(s):  
Colin Bouchard ◽  
Mathieu Buoro ◽  
Clément Lebot ◽  
Stephanie M Carlson
Keyword(s):  
Atlantic Salmon ◽  
Environmental Conditions ◽  
River Flow ◽  
Multiple Scales ◽  
Low Flow ◽  
Moran Effect ◽  
Spatial Synchrony ◽  
Flow Conditions ◽  
Spatio Temporal ◽  
Regional Synchrony

Dispersal and shared environmental conditions can both synchronize the dynamics of local populations, but disentangling their relative influence on dynamics is challenging. We used a Bayesian approach to estimate the synchrony of a metapopulation of Atlantic salmon composed of 18 populations in Brittany, France, including a 24-year time-series of the abundances of juveniles. We estimated the spatial synchrony at a regional and local spatial scale over the study period. We found a strong regional synchrony despite spatio-temporal variability of local synchrony in the abundance of juveniles. We then explored the drivers of synchrony, including environmental conditions (aspects of river flow) and abundance of adult breeders. This revealed that summer low-flow conditions seemed to synchronize the abundances of juveniles more than the synchrony in the abundance of adult breeders, suggesting a Moran effect. Given that drought conditions are expected to become more common with climate change, our work highlights the potentially strong synchronizing effect of summer low-flow on the dynamics of local salmon populations and the benefits of considering synchrony at multiple scales.

Spatial synchrony in vole population fluctuations - a field experiment

Oikos ◽  
2005 ◽  
Vol 109 (3) ◽  
pp. 583-593 ◽  
Author(s):  
Otso Huitu ◽  
Jesse Laaksonen ◽  
Kai Norrdahl ◽  
Erkki Korpimäki
Keyword(s):  
Field Experiment ◽  
Population Fluctuations ◽  
Vole Population ◽  
Spatial Synchrony
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