Tökölyi et al. (2014) Biological Journal of the Linnaean Society

Tökölyi, J., Schmidt, J. and Barta, Z. (2014), Climate and mammalian life histories. Biological Journal of the Linnean Society, 111: 719–736. doi: 10.1111/bij.12238
http://onlinelibrary.wiley.com/doi/10.1111/bij.12238/abstract

 

Abstract
Mammals display considerable geographical variation in life history traits. To understand how climatic factors might influence this variation, we analysed the relationship between life history traits – adult body size, litter size, number of litters per year, gestation length, neonate body mass, weaning age and age at sexual maturity – and several environmental variables quantifying the seasonality and predictability of temperature and precipitation across the distribution range of five terrestrial mammal groups. Environmental factors correlated strongly with each other; therefore, we used principal components analysis to obtain orthogonal climatic predictors that could be used in multivariate models. We found that in bats, primates and even-toed ungulates adult body size tends to be larger in species inhabiting cold, dry, seasonal environments, whereas in carnivores and rodents a smaller body size is characteristic of warm, dry environments, suggesting that low food availability might limit adult size. Species inhabiting cold, dry, seasonal habitats have fewer, larger litters and shorter gestation periods; however, annual fecundity in these species is not higher, implying that the large litter size of mammals living at high latitudes is probably a consequence of time constraints imposed by strong seasonality. On the other hand, the number of litters per year and annual fecundity were greater in species inhabiting environments with higher seasonality in precipitation. Lastly, we found little evidence for specific effects of environmental variability. Our results highlight the complex effects of environmental factors in the evolution of life history traits in mammals.

 

Keywords
body size, comparative analysis, macroecology, predictability, reproductive traits, seasonality

Stenger-Kovács et al. (2013) Ecological Indicators

C. Stenger-Kovács, E. Lengyel, L.O. Crossetti, V. Üveges, J. Padisák (2013): Diatom ecological guilds as indicators of temporally changing stressors and disturbances in the small Torna-stream, Hungary. Ecological Indicators 24: 138–147.http://dx.doi.org/10.1016/j.ecolind.2012.06.003


Abstract
In this research, indicator properties of the three recently described diatom ecological guilds (low profile, high profile and motile) and their responses to different stressors and disturbances were tested along a temporal gradient. Experiments were run at a standard sampling site in the Torna-stream (Hungary) between 2008 and 2010 using standardized substrata. The low profile guild was dominant during periods with low nutrient (SRP and TN) availability. In contrast, the high profile guild was dominant in resource rich (SRP and SRSi) periods. The motile ecological guild was the most sensitive to the nutrients (TN and SRSi) and some other factors (e.g. temperature, Cl−). Increasing irradiance in spring and summer favored the growth of the high and the low profile guild. Higher resistance to floods favored the adhesion type of the low profile guild enabling their summer peak in terms of relative abundance. During high flood periods, incident light availability apparently sufficed the needs of this guild. Seasonal changes of the diatom ecological guilds and guild diversity were robust and predictable. This study supported that the ecological responses of diatom ecological guilds, despite the apparent simplicity of the grouping method, is strong enough to indicate the temporally changing environmental conditions.


Keywords
Diatom ecological guilds, Stressors, Disturbances, Seasonality, Torna-stream

Bereczki et al. (2012) Aquatic Insects

Csaba Bereczki, Ildikó Szivák, Arnold Móra, Zoltán Csabai (2012): Variation of aquatic insect assemblages among seasons and microhabitats in Hungarian second-order streams. Aquatic Insects 34 (sup1): 103-112. DOI:10.1080/01650424.2012.643032



Abstract
The assemblages of aquatic insects are important members of water ecosystems. Based on former studies among the most important factors structuring the assemblages are numerous abiotic ones, such as the sort and the particle size of the substratum. Most of the sampling protocols, e.g. AQEM, determine microhabitats based on those. Nevertheless, we have no information yet about whether or not these different, precisely determined microhabitats have different assemblages. In this study we compared the aquatic insect assemblages of different microhabitat types in three seasons using ADONIS and linear discriminant analyses. We proved that seasonal changes of abiotic factors had a major role in structuring the assemblages. In spring and summer the assemblages differed significantly, however, in autumn no significant differences were found. We supposed that the variation among the assemblages was due to the abundance patterns of frequent species instead of the presence of rare or sparse species. The indicator species analyses also corroborated this suppososition while symmetrical indicator species were not found.


Keywords
microhabitat, seasonality, aquatic insects, linear discriminant analysis, ADONIS, indicator species