The altitudinal gradient in diversity of dung beetles (Scarabaeidae) was studied in a Mediterranean mountain chain located in Central Anatolia to (i) determine if there are altitudinal differences between the main taxonomic groups, (ii) describe the seasonal variations in these assemblages and (iii) assess whether closed habitats influence dung beetle diversity differentially at different altitudes. Beetles were collected throughout a year at 14 localities between 469 and 1810 m above sea level in three different types of habitats. Dung beetle assemblages at 400 to 1200 m did not vary greatly in species richness, abundance and biomass. However, they varied in composition, with the assemblages dominated by species of Scarabaeinae up to 900 m, whereas in the mid-mountain assemblages (from 900 m to 1600 m) the numbers of species of Aphodiinae was higher. The decline with increase in altitude in richness, abundance and biomass of both small and large species of Scarabaeinae up to 1500 m, together with the constancy of these parameters in the case of Aphodiinae, accounts for the changes in the composition from the lowland to mid-mountain localities. Unlike at other Mediterranean localities, the open/closed structure of the habitat only slightly influences these assemblages independently of altitude or season. The general seasonal pattern follows the classical Mediterranean bimodal pattern associated with summer drought, but the patterns are more complex when the seasonal responses of the different groups and at different localities are analysed separately. We propose that the interplay between local climatic conditions (mainly temperature) and evolutionary conserved species preferences accounts for both the current seasonal and altitudinal gradients and the changes in species composition in terms of Aphodiinae and Scarabaeinae.
The peaks over threshold method (POT method) is an alternative to the block-maxima method for estimating return levels (these are the levels that are exceeded by a daily precipitation, resp. by a daily average discharge, only with a given small probability; in statistical language they are called high quantiles) when the studied series are not long enough. The paper compares both methods for precipitation and discharges series of Northern Moravia. It is shown how to overcome problems in the POT method caused by autocorrelation and seasonality. and Metoda špiček nad prahem může sloužit při odhadování vysokých kvantilů (to znamená takových hodnot, že je denní úhrnná srážka, respektive denní průměrný průtok, překročí jen s malou předem danou pravděpodobností). Jedná se o alternativu k metodě blokových maxim, a to zvláště tam, kde studované řady nejsou příliš dlouhé. Článek porovnává výsledky obou metod na příkladech srážkových a průtokových dat ze severní Moravy. Ukazuje dále, jak lze v metodě POT překonat problémy spojené s autokorelací a sezónností řad.