Introduction

Over the last few decades attention has increasingly focused on evolutionary responses to the ability of longlived species to adapt to climate change(Lindner et al.2009).Stressful environments,such as mountain ecosystems,provide an ideal experimental setting for studying adaptation in such species(Lesica and McCune 2004).In these areas,sharp changes in abiotic factors occur over short distances,leading to major changes in the selection pressures acting on plant life-history traits(Vitasse et al.2010).Altitudinal gradients provide an opportunity for analysing the variation of functional traits in response to environmental factors and their implications for the capacity of populations to respond to changing environments(K?rner 2007).Along an altitudinal gradient,the divergence between populations may be influenced by differences in the selective pressures imposed by different environments,neutral evolutionary processes or both(Still et al.2005).Morphological and physiological adjustments allow individuals to persist in the stressful instance,some plants have distinctive morphological features such as including dwarfness or densely pubescent factors and evolutionary processes affecting bud phenology have been widely studied,but little is known of the factors affecting morphological or physiological leaf traits(Premoli and Brewer 2007).

Common oak(Quercus roburL.)is an important species in Europe in different ecological conditions(Stoyanova and Zhiyanski 2004;Kavgaci et al.2010).Fukarek(1959)proposed an infra-specific classification system,citing the following taxa:,(Vukot.)Beck.,(Heuff.)Simk.,,,and (Lamk) ?ili?(2005)refers to only two subspecies in the Dinaric hinterland and the Sava valley a result of past human actions there are presently remnant forests with low economic importance(Memisěvi?2008).A survey of forested areas reveals areas of 1,130,183 and 841,303 ha for high and coppice forests, forest comprises beech(Fagus sylvaticaL.), fir(Abies albaL.)and spruce(Picea abies(L.)Karst.),Austrian(Pinus )and Scotspine(PinussylvestrisL.),and sessileoak(Quercus petraea(Matt.)Liebl.).The area covered byQuercus %(10,260 ha).However,varioussources indicate that common oak once covered much larger areas which were felled over a period of 80 years,1830– 3,600,000 mature oaks were felled to produce staves for manufacturing barrels in France,and 375,000 m3of cordwood from trees tumps(Memisěvi?2008),hence most current oak forests are from natural regeneration(Diaz-Maroto et al.2005).

Reducing the area of common oak is the result of many factors other than human impacts(Diaz-Maroto et al.2015).In upland regions,natural hybridization with sessile oak gives rise to numerous hybrid swarms and creates identification are processes known as dictating the very marked intra-and inter-population variations between both species(Aldrich and Cavender-Bares 2011)and leads to great polymorphism and variability in morphological traits.

Our aim was to determine if altitudinal variation promotes morphological discrimination among different natural populations of common oak in Bosnia and Herzegovina within an altitudinal gradient of almost 700 m,and to define the elevation of the studied study is of particular value for the renewal and conservation of the species using both in situ and ex situ methods.

Materials and methods

Quercus roburforests covered large areas in Bosnia and Herzegovina and had an important economic ,mainly due to human activities,the forests have declined decline is compounded by its polymorphism and variability of morphological features,indicative of introgressive hybridization of the partial reproductive isolation between oak species(Diaz-Maroto and Vila-Lameiro 2007).

During our study,the intra-population and inter-population variations of certain morphological traits of the foliage were material was collected in the summer and autumn of 2007 and 2008(July to October)at every location where a group of at least 10 naturally occurring oaks was material was collected from 44 populations,both from self-seeded and planted oaks(Fig.1;Table 1).

Fig.1 General map of the Balkans location and specific map with the populations ofQuercus roburin Bosnia and Herzegovina

Table 1 Geographical characteristics and altitudinal classes of populations ofQuercus roburin Bosnia and HerzegovinaNo. Population name Latitude Longitude Elevation Class 1 Ora?je—Donji Zǎbari 45°00′17′′18°37′23′′82 1 2 B.Brod—Zbori?ta 45°05′27′′18°00′38′′84 1 3 Brezovo polje-Vrsani Br?ko 44°49′26′′19°03′39′′84 1 4 Br?ko—Brka 44°53′49′′18°42′17′′87 1 5 Gradi?ka—Lipnica 45°07′04′′17°18′63′′91 1 6 Bijeljina—Patkovacǎ 44°43′50′′19°13′30′′93 1 7 Orahova 45°11′11′′17°04′25′′96 1 8 Janja—Glavicica 44°36′40′′19°11′55′′124 2 9 Srebrenik—Dubrave 44°49′06′′18°34′11′′133 2 10 Novi Grad(B.Novi) 45°02′29′′16°26′06′′136 2 11 Zvornik—Aluminij 44°25′01′′19°07′22′′141 2 12 Srbac 44°57′23′′17°25′14′v 142 2 13 B.Dubica—Kne?ica 45°06′24′′16°40′32′′145 2 14 Zaluzǎni 44°48′40′′17°12′03′′146 2 15 Prijedor—Rastavci 44°54′56′′16°41′86′′147 2 16 Prnjavor 44°51′49′′17°40′42′′151 2 17 Jelah 44°39′09′′17°56′46′′181 2 18 Sanski Most—Vrhpolje 44°42′31′′16°44′19′′190 2 19 ?ivinice— 44°27′58′′18°41′09′′216 3 20 Zěpcě 44°25′35′′18°03′10′′224 3 21 Ripa? 44°46′31′′15°55′55′′229 3 22 Sěher 44°30′09′′18°02′02′′230 3 23 Kotor Varo? 44°39′07′′17°21′35′′252 3 24 Klju?—Velecěvo 44°30′56′′16°48′42′′260 3 25 Cazin—Mutnica 44°58′55′′15°50′54′′270 3 26 Vinac—Bila Voda 44°15′48′′17°17′08′′408 4 27 Visoko 44°00′38′′18°08′45′′413 4 28 Ka?uni—Nezirovi?i 44°03′59′′17°56′13′′443 4 29 Drvar 44°23′39′′16°21′54′′462 4 30 Nevi?polje 44°11′46′′17°42′11′′476 4 31 Kiseljak 43°56′30′′18°04′56′′477 4 32 Bojnik 43°52′41′′18°17′34′′489 4 33 Ilidzǎ—Stojcěvac 43°48′40′′18°17′25′′506 5 34 Brestovsko 44°00′29′′18°01′30′′508 5 35 Bugojno—Kop?i? 44°06′00′′17°26′31′′537 5 36 Olovo—Luke 44°07′44′′18°36′11′′542 5 37 Lukavica 43°49′26′′18°21′58′′552 5 38 Miljevina 43°31′06′′18°38′56′′627 6 39 Bosanski Petrovac 44°33′20′′16°22′25′′672 6 40 Posu?je 43°27′62′′17°19′42′′675 6 41 Livno—Crni lug 44°01′05′′16°38′24′′703 7 42 Mrkonji?Grad—Zěravica 44°27′04′′16°58′42′′753 7 43 Kne?ina 44°01′40′′18°44′53′′759 7 44 Sokolac 43°55′17′′18°48′53′′866 7