Effect of weather factors on growth and development of European Mouflon (Ovis aries musimon Pall.) horns in continental Croatia

Abstract

Rogovi kod porodice Bovidae predstavljaju sekundarno spolno obilježje jednog ili oba spola. Kod muflonske divljači rogovi se uglavnom pojavljuju kod muškog spola, a u iznimnim slučajevima mogu se pojaviti i kod ženki, ali mnogo manji nego kod mužjaka. Analizom rogova mogu se dobiti važne informacije o životu jedinke i populacije. U istraživanjima opisanim u analiziranoj literaturi klima i okolišni čimbenici pokazali su se značajnim za rast rogova uz ostale čimbenike poput selekcije, trofejnog lova, veličine populacije, dobne strukture unutar populacija, i drugih. Cilj ovog istraživanja je testirati može li se ovisnost duljine drugog segmenta, odnosno godišnjeg prirasta rogova muflona (Ovis aries musimon Pall.) iz lovišta Garjevica objasniti okolišnim čimbenicima (temperaturom i padalinama). U istraživanju su kao prediktori za model prirasta roga korištene minimalna i maksimalna proljetna temperatura (ožujak, travanj, svibanj) te prosječna količina padalina za proljetni period. U modelu su analizirane duljine drugog segmenta roga, a uzorkovane su 83 trofeje muflona, stečenih u državnom otvorenom lovištu broj: VII/15 – „ZAPADNA GARJEVICA“, u periodu od 1992. do 2002. godine. Velika varijabilnost prirasta roga unutar istih kalendarskih godina, uz iste okolišne uvjete, te nedovoljan broj prediktora rasta uključenih u model, ukazuju na neadekvatnost ovakvog pojednostavljenog modela za opis rasta rogova muflona na ovom području.Horns in the Bovidae family represent the secondary sex characteristic of one or both sexes. At wild mouflons, horns usually occurs in male sex, but in exceptional cases they may occur in female sex but much less often than in males. By analyzing horns, important information about the life of the individual and the population can be obtained. In the studies described in the analyzed literature, climate and environmental factors have proved to be significant for the growth of horns along with other factors such as selection, trophy hunting, population size, age structure in the population and others. The objective of this study is to test whether the dependence of the length of the second segment, or the annual growth of mouflons horns (Ovis aries musimon Pall.) from the Garjevica hunting ground can be explained by environmental factors (temperature and precipitation). In the study, the minimum and maximum spring temperatures (March, April, May) and the average rainfall for the spring period were used as predictors for the horn growth model. In the model it was analyzed the lengths of the second horn segment, and 83 trophies of mouflon were sampled, obtained in the state open hunting ground number: VII / 15 - "ZAPADNA GARJEVICA", in the period from 1992 to 2002. The high variability of horn growth within the same calendar years, with the same environmental conditions, and the insufficient number of growth predictors involved in the model, indicate the inadequacy of such a simplified model for describing the growth of mouflons horns in this area