Effects of acorn abundance on density dependence in a Japanese wood mouse (<i>Apodemus speciosus</i>) population

Saitoh, Takashi; Vik, Jon Olav; Stenseth, Nils Chr.; Takanishi, Toshikazu; Hayakashi, Shintaro; Ishida, Naoto; Ohmori, Makiko; Morita, Toshio; Uemura, Shigeru; Kadomatsu, Masahiko; Osawa, Jun; Maekawa, Koji

doi:10.1007/s10144-008-0076-6

Cited by 18 publications

(12 citation statements)

References 40 publications

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“…At this study site, Apodemus mice reproduce only once a year from late autumn to early spring (Oishi et al 2010), and the mice population could not increase immediately in the mast years as reported by Miguchi (1988) and Saitoh et al (2008). This delayed increase in Apodemus mice population after mast cropping could produce a condition in which Apodemus mice acted as a seed disperser; mast cropping and a small population of Apodemus mice.…”

Section: Discussionsupporting

confidence: 48%

Determinant factors in the seedling establishment of Pasania edulis (Makino) Makino

Nakamura

Hirata

Oishi

et al. 2013

Ecological Research

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Pasania edulis (Makino) Makino is one of the dominant Fagucea tree species in evergreen broad‐leaved forests in southern Japan, and its regeneration success may have a major impact on the dynamics of evergreen broad‐leaved forests. We conducted a field survey on the population process from acorn production to seedling establishment of P. edulis in an evergreen broad‐leaved forest in Kagoshima, southern Japan, from 1995 to 2009. The acorn crop varied greatly among the 14 cohorts, with mast cropping being recorded every 3–4 years. The mortality rate of acorns was very high for all 14 cohorts (99.3–100 %). Important mortality factors were failure to mature (empty acorns), attack by Curculio weevil on trees, predation of dropped acorns by Apodemus mice and large or medium‐sized mammals (wild boar (Sus scrofa leucomystax), badger (Meles meles anakuma), and raccoon dog (Nyctereutes procyonoides viverrinu)), and attacks on germinated acorns by the acorn borer (Coccotrypes graniceps). Among these factors, predation by Apodemus mice was the greatest contributor to annual fluctuations in total mortality until seedling establishment. Large or medium‐sized mammals and the acorn borer also caused severe damage to dropped acorns in some years, but contributed little to annual fluctuations in total mortality. For successful regeneration, mast cropping was essential. However, a small population of Apodemus mice, that is, a low predation pressure, was also required during mast years.

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Section: Discussionsupporting

confidence: 48%

Determinant factors in the seedling establishment of Pasania edulis (Makino) Makino

Nakamura

Hirata

Oishi

et al. 2013

Ecological Research

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“…Examination of residuals of both N t−1 against N t and N t−1 against r t allowed us to determine evidence for non‐linear effects of density. Simple linear models are still commonly used to investigate direct DD in animal populations (Saitoh et al 2008, Wang et al 2009).…”

Section: Methodsmentioning

confidence: 99%

“…Examination of residuals of both N t21 against N t and N t21 against r t allowed us to determine evidence for non-linear effects of density. Simple linear models are still commonly used to investigate direct DD in animal populations (Saitoh et al 2008, Wang et al 2009). Second, we used linear autoregressive models to estimate DDD, after accounting for DD effects, which a widespread method in population ecology (Ziebarth et al 2010).…”

Section: Statistical Analysesmentioning

confidence: 99%

Tests of density dependence using indices of relative abundance in a deer population

Simard

Côté

Gingras

et al. 2012

Oikos

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A major question in animal ecology is explaining the causes of population fluctuations. Consensus about the most reliable method to detect density dependence (DD) or environmental effects from time‐series data, however, has not yet been achieved. Times series analyses have been used with indices of relative abundance in numerous studies, although these indices are rarely validated. Here, we used three different time series of relative abundance (number of deer seen per hunter per day, hunting success and proportion of males in the harvest) to explore direct and delayed DD in a white‐tailed deer Odocoileus virginianus population on Anticosti Island, Québec, Canada. Three mathematical approaches were tested: linear models, autoregressive (AR) models, and total DD in life history. Tests of DD using different indices of abundance on the same population should lead to similar results if all indices exhibit similar behaviour. Indices of relative abundance correlated with each other, although sometimes weakly, such that we obtained similar DD estimates with each index using detrended non‐stationary series. In most time series, linear regression of Nt−1 and Nt and AR models did not detect DD, while we obtained strong evidence for DD from the life‐history approach. This meant that contrasting conclusions about the role of density dependence within this population were reached depending on which method was used. We conclude that the method that incorporates most biological realism, the life‐history approach, provided a different result than classical interpretation of autoregressive coefficients. Only the life‐history interpretation supported our a priori belief that density dependence operating through competition for food regulates the Anticosti deer population. Phenomenological analysis aiming to investigate changes in abundance should be carefully conducted as the use of inappropriate indices or methods could lead to inappropriate conclusions or management strategies. Preferably, the method used should match the time scale of the population sampling regime and species life history.

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“…Recent advances in population ecology include the elucidation of processes that determine wildlife population growth in a wide range of taxa. These advances were achieved by means of a statistical approach in which logistic growth models were used for testing the structure of density‐dependent regulation (Turchin 1990, Sibly et al 2005, Brook and Bradshaw 2006), estimating the effects of density‐dependent and density‐independent processes on population growth rate (Forchhammer et al 1998, Sæther et al 2008, Rotella et al 2009), and quantifying spatiotemporal variations in patterns and processes of population dynamics (Williams et al 2003, Liebhold et al 2006, Saitoh et al 2008, Fukaya et al 2010).…”

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confidence: 99%

Patterns and processes of population dynamics with fluctuating habitat size: a case study of a marine copepod inhabiting tide pools

Fukaya

Shirotori

Kawai

et al. 2012

Oikos

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The logistic model is a fundamental population model often used as the basis for analyzing wildlife population dynamics. In the classic logistic model, however, population dynamics may be difficult to characterize if habitat size is temporally variable because population density can vary at a constant abundance, which results in variable strength of density-dependent feedback for a given population size. To incorporate habitat size variability, we developed a general population model in which changes in population abundance, density, and habitat size are taken into account. From this model, we deduced several predictions for patterns and processes of population dynamics: (1) patterns of fluctuation in population abundance and density can diverge, with respect of their correlation and relative variability; and (2) along with density dependence, habitat size fluctuation can affect population growth with a time lag because changes in habitat size result in changes in population density. In order to test these predictions, we applied our model to population dynamics data of 36 populations of Tigriopus japonicus, a marine copepod inhabiting tide pools of variable sizes caused by weather processes. As expected, we found a significant difference in the fluctuation patterns of population abundance and density of T. japonicus populations with respect to the correlation between abundance and density and their relative variability, which correlates positively with the variability of habitat 3 size. In addition, we found direct and lagged-indirect effects of weather processes on population growth, which were associated with density dependence and impose regulatory forces on local and regional population dynamics. These results illustrate how changes in habitat size can have an impact on patterns and processes of wildlife population dynamics. We suggest that without knowledge of habitat size fluctuation, measures of population size and its variability as well as inferences about the processes of population dynamics may be misleading.4

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Effects of acorn abundance on density dependence in a Japanese wood mouse (Apodemus speciosus) population

Cited by 18 publications

References 40 publications

Determinant factors in the seedling establishment of Pasania edulis (Makino) Makino

Determinant factors in the seedling establishment of Pasania edulis (Makino) Makino

Tests of density dependence using indices of relative abundance in a deer population

Patterns and processes of population dynamics with fluctuating habitat size: a case study of a marine copepod inhabiting tide pools

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