Density Dependence in Time Series of the Fossorial Form of the Water Vole, Arvicola terrestris

Saucy, Francis

doi:10.2307/3545826

Cited by 71 publications

(64 citation statements)

References 31 publications

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“…The conclusion that large-scale weather patterns set the stage for synchrony of lemming and vole cycles in the Canadian Arctic is compatible with an increasing set of papers in which weather is implicated in vertebrate population dynamics Saether et al 2000;Saucy 1994;Moss et al 2001). In ecology, weather has typically been thought of as a disturbance, a density-independent factor that can rarely be used to explain patterns in dynamics.…”

Section: Discussionmentioning

confidence: 59%

Synchrony in lemming and vole populations in the Canadian Arctic

Krebs¹,

Kenney²,

Gilbert³

et al. 2002

Can. J. Zool.

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Population fluctuations may occur in synchrony among several rodent species at a given site, and they may occur in synchrony over large geographical areas. We summarize information on synchrony in lemmings and voles from the Canadian Arctic for the past 20 years. The most detailed available information is from the central Canadian Arctic, where snap-trap samples have been taken annually at several sites for periods of up to 15 years. Geographical synchrony in the same species among different sites was strong, especially for the central and eastern Canadian Arctic. Synchrony among different species at a given site was also generally high. When one species is at high density, densities of all species at that site tend to be high. These results do not easily fit the mobile-predator hypothesis proposed to explain regional synchrony, and are more consistent with the weather hypothesis, which we suggest both entrains synchrony among sites and enforces synchrony among species within a site. We tentatively support the weather hypothesis for geographical synchrony in lemmings, and recommend the establishment of a circumpolar program to monitor lemming cycles and predator movements that would advance our understanding of these large-scale patterns of cyclic synchrony.Résumé : Les densités de plusieurs espèces de rongeurs peuvent fluctuer en même temps à un endroit donné et ces fluctuations peuvent aussi être synchrones sur une échelle géographique très grande. Nous résumons ici des informations sur le synchronisme des lemmings et des campagnols dans l'arctique canadien depuis 20 ans. Les informations les plus detaillées proviennent de la région centrale de l'arctique, où des recensements annuels par trappage destructif ont été effectués à plusieurs sites pour une période allant jusqu'à 15 ans. Pour chaque espèce, le synchronisme géogra-phique entre les différents sites est très fort entre les différents sites, et plus spécialement aux sites du centre et de l'est de l'arctique canadien. De même, le synchronisme entre les différentes espèces d'un même site est habituellement fort. Quand la densité d'une espèce devient haute, les densités de toutes les espèces à cet endroit ont aussi tendance à augmenter. Ces résultats sur le synchronisme géographique sont difficilement attribuables à l'hypothèse des prédateurs mobiles, mais semblent plutôt reliés à l'hypothèse météorologique selon laquelle les conditions météorologiques entraînent le synchronisme entre les sites et, de plus, forcent les espèces à être synchrones à un même site. Nous croyons pouvoir supporter l'hypothèse météorologique dans le cas du synchronisme géographique des lemmings et recommandons un suivi à l'échelle circumpolaire du cycle des lemmings et des déplacements des prédateurs ce qui contribuerait à parfaire nos connaissances sur les cycles synchrones à grande échelle. Krebs et al. 1333

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Section: Discussionmentioning

confidence: 59%

Synchrony in lemming and vole populations in the Canadian Arctic

Krebs¹,

Kenney²,

Gilbert³

et al. 2002

Can. J. Zool.

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“…Of the black-swan events with published explanations (SI Appendix, Table S2), the majority involved a combination of factors. For example, a synchronization of environmentaland predation-mediated population cycles is thought to have caused a downward black-swan event for a water vole (Arvicola amphibius) population (21). Other black swans were the result of a sequence of extreme climate events on their own.…”

Section: Resultsmentioning

confidence: 99%

Black-swan events in animal populations

Anderson

Branch

Cooper

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

104

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Black swans are improbable events that nonetheless occur-often with profound consequences. Such events drive important transitions in social systems (e.g., banking collapses) and physical systems (e.g., earthquakes), and yet it remains unclear the extent to which ecological population numbers buffer or suffer from such extremes. Here, we estimate the prevalence and direction of black-swan events (heavy-tailed process noise) in 609 animal populations after accounting for population dynamics (productivity, density dependence, and typical stochasticity). We find strong evidence for black-swan events in ∼4% of populations. These events occur most frequently for birds (7%), mammals (5%), and insects (3%) and are not explained by any life-history covariates but tend to be driven by external perturbations such as climate, severe winters, predators, parasites, or the combined effect of multiple factors. Black-swan events manifest primarily as population die-offs and crashes (86%) rather than unexpected increases, and ignoring heavy-tailed process noise leads to an underestimate in the magnitude of population crashes. We suggest modelers consider heavy-tailed, downward-skewed probability distributions, such as the skewed Student t used here, when making forecasts of population abundance. Our results demonstrate the importance of both modeling heavy-tailed downward events in populations, and developing conservation strategies that are robust to ecological surprises.mass mortality | ecological surprises | population dynamics | die-offs | ecological risk M ajor surprises (black-swan events) happen more often than expected in financial, social, and natural systems (1-5). Massive unpredictable market swings are responsible for the majority of financial gains and losses (3), fatalities from the largest wars dwarf those from all others (6), and the frequency of the most damaging earthquakes has exceeded past expectations (5). In ecological systems, background rates of global extinction are punctuated by mass extinction (7), evolution is characterized by long periods of stasis interrupted by bursts of speciation (8), and billions of animals can die at once in mass mortality events (9).Indeed, such die-offs may be the most important element affecting population persistence (10) and their importance is likely to increase given projected increases in the frequency and magnitude of climate-related extremes (11). However, the overwhelming majority of population model-fitting and risk-forecasting assumes that deviations from model predictions can be represented by a normal distribution [on a log scale (e.g., refs. 12 and 13)]. If black swans occur, however, a normal distribution would underestimate the probability of extreme events occurring (3).Whereas there are many reports of black-swan events, only a flexible comparative approach consistently applied to a large number of time series can yield insights into the frequency, strength, and correlates of such events. We are unaware of such a comparative analysis. Previous comparative an...

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“…Regional transitions in pattern of density fluctuations and density-dependence are features of the population dynamics of microtine rodents elsewhere (Hansson andHenttonen 1985, 1988;Hanski et al 1991;Stenseth and Ims 1993;Bj0rnstad et al 1995): varying influence of both direct and delayed density-dependence appear to be quite general (Hornfeldt 1994;Saucy 1994;Bj0rnstad et al 1995;Stenseth et al 1996b). Self-regulation through spacing behavior and social interaction between voles is a plausible mechanism for the direct density-dependence ; see also Stenseth et al 1996b).…”

Section: Cyclicity and Density-dependencementioning

confidence: 99%

“…Our appreciation and understanding of the pattern of fluctuation has improved greatly during the last few decades, partly due to the accumulation of relatively long time series (Saitoh 1987;Turchin 1990;Hornfeldt 1994;Saucy 1994;Bj0rnstad et al 1995;Stenseth et al 1996aStenseth et al , 1998a. The most extensive set of data on any small rodent species is the census data on the gray-sided vole (Clethrionomys rufocanus (SundevaII, 1846)) in Hokkaido, Japan.…”

Section: Introductionmentioning

confidence: 99%

The population dynamics of the vole Clethrionomys rufocanus in Hokkaido, Japan

1998

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Abstract. Population dynamics of the gray sided-vole, Clethrionomys rufocanus, in Hokkaido, Japan were described on the basis of 225 time series (being from 12 to 31 years long); 194 of the time series have a length of 23 years or longer. The time series were classified into 11 groups according to geographic proximity and topographic characteristics of the island of Hokkaido. Mean abundance varied among popUlations from 1.07 to 21.07 individuals per 150 trap-nights. The index of variability for population fluctuation (s-index) ranged from 0.204 to 0.629. Another index for population variability (amplitude on 10g-1O scale) ranged from 0.811 to 2.743. Mean abundance and variability of populations were higher in the more northern and eastern regions of the island. Most populations, except for the southernmost populations, exhibited significant direct density-dependence in population growth. Detection rate for delayed density-dependence varied among groups from 0% to 22.6%. Both direct and delayed density-dependence tended to be stronger in the more northern and eastern populations. The proportion of cyclic populations was higher in the northern-eastern areas than that in the southern-western areas. There was a clear gradient from the asynchronous populations in southwest, to the highly synchronized populations in the northeast.

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Density Dependence in Time Series of the Fossorial Form of the Water Vole, Arvicola terrestris

Cited by 71 publications

References 31 publications

Synchrony in lemming and vole populations in the Canadian Arctic

Synchrony in lemming and vole populations in the Canadian Arctic

Black-swan events in animal populations

The population dynamics of the vole Clethrionomys rufocanus in Hokkaido, Japan

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