Fluctuating Asymmetry and Population Dynamics of the Common Shrew, Sorex araneus, in Central Siberia under Climate Change Conditions

Abstract

We examine possible temporal variation in a measure of developmental stability, providing insight into the degree of fluctuating asymmetry of several characters of skull morphology, of the common shrew, Sorex araneus L., 1758, in Central Siberia. The level of fluctuating asymmetry during the study period in the beginning of this century (2002–2013) is not correlated with population abundance, while at the end of the last century it was correlated with population abundance, suggesting that high density was the important negative factor affecting breeding females. The absence of an adverse effect of high abundance on developmental stability in the current situation can be related to both an impact of oscillations in environmental conditions and an increase in habitat carrying capacity due to the climate change. Positive correlation of population abundance with the number of adults born last summer and young specimens born this summer indicates the influence of winter and summer conditions on population size. If in the last century developmental stability was correlated with breeding success, indicating that both parameters were affected by the physiological condition of breeding females, in this century these two parameters vary independently, suggesting that breeding success may be affected by other population and habitat factors. Thus, the situation in the population under study is more similar to the noncyclic dynamics than to the four-year cycles, which were revealed for the population in the last century. The results indicate an importance of monitoring possible changes in developmental stability measure, as another population parameter, under climate change.

Are population cycles recovering?

“…For the population of S. araneus in the studied community, the effect of overpopulation during peak years in the last century was accompanied by a decrease in breeding success and a violation of developmental stability (Zakharov et al 1991). During the period of fluctuations, no negative impact of changes in numbers on the stability of development was observed (Zakharov et al 2020). However, cyclical fluctuations tend to recover in recent years.…”

“…During this period, the trend of positive correlation between population size and breeding success in the model species S. araneus persisted; however, there was no violation of the stability of development (Zakharov et al. 2011, 2020). A change in the patterns of dynamics occurred in other regions of the Holarctic, for example, in Hokkaido, Japan (Saitoh et al.…”

“…A preliminary analysis of the entire community of small mammals showed that at the end of the 20thbeginning of the 21st century, cyclical fluctuations were replaced by noncyclical ones (Sheftel & Yakushov 2022). During this period, the trend of positive correlation between population size and breeding success in the model species S. araneus persisted; however, there was no violation of the stability of development (Zakharov et al 2011(Zakharov et al , 2020. A change in the patterns of dynamics occurred in other regions of the Holarctic, for example, in Hokkaido, Japan (Saitoh et al 2006), Scotland (Bierman et al 2006), Norway (Ims et al 2008), Sweden (Hörnfeldt 2004), and Canada (Berteaux et al 2006).…”

Developmental Noise and Biological System Condition: Prolegomena

“…Moreover, such changes take place before significant changes in the viability of the organism occur (Figure 1) [4,[18][19][20]. An increase in the noise level is usually observed with a change in the fitness parameters, such as the breeding success index, indicating a deterioration of developmental stability [18,[21][22][23][24][25].…”

“…This form of variability, along with genetic variability, acts as one of the main sources of the observed intrapopulation phenotypic diversity [4,19,26]. Under normal conditions, the level of developmental noise does not show consistent changes even for correlated morphological traits, while at the same time, under stressful exposure, the noise level An increase in the noise level is usually observed with a change in the fitness parameters, such as the breeding success index, indicating a deterioration of developmental stability [18,[21][22][23][24][25].…”