Raznolikost flore mahovina duž visinskih gradijenata primorskih Dinarida

doctoral thesis

• Title (english): Diversity of bryophyte flora along the altitudinal gradients of littoral Dinarides
• Author: Vedran Šegota
• Mentor: Antun Alegro (mentor)
• Committee member: Renata Šoštarić (predsjednik povjerenstva)
• Committee member: Joso Vukelić (član povjerenstva)
• Committee member: Ivančica Ternjej (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2021-07-09, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 57 - Biological sciences. Physical anthropology. Biodiversity

Abstract

Usporedno istraživanje visinskih distribucija mahovina i vaskularnih biljaka na primorskim Dinaridima provedeno je na dva cjelovita visinska transekta u Gorskom kotaru i na Sjevernom Velebitu s rasponom nadmorskih visina od oko 1500 m. Zabilježeno je ukupno 570 biljnih svojti, od čega 185 vrsta mahovina, što čini čak četvrtinu dosad poznate raznolikosti mahovine Hrvatske. Obje skupine pokazuju slične obrasce alfa raznolikosti, koje najbolje opisuje kubna regresijska funkcija s maksimumima raznolikosti otprilike između 1100 i 1200 m n. m. Ukupni broj svojti vaskularnih biljaka i mahovina najmanji je u najnižem pojasu hrasta crnike, a najviši u kompleksu zajednica smreke. Visoka brojnost i unutarpojasna beta raznolikost vaskularne flore u pojasevima bijelog i crnog graba na Sjevernom Velebitu posljedica je stoljetne intenzivne degradacije ovih šuma, što je omogućilo naseljavanje velikog broja nešumskih vrsta. Vaskularne biljke imaju najizraženiji obrat svojti na granici dviju fitogeografskih regija, a najveći se obrat svojti mahovina javlja s pojavom crnogoričnih borealnih i pretplaninskih tipova vegetacije. Mahovine pokazuju šire visinske raspone i veću sklonost isključivo višim nadmorskim visinama u odnosu na vaskularne biljke. Ni vaskularne biljke niti mahovine ne slijede Rapoportovo pravilo povećanja prosječnog raspona područja rasprostranjenosti vrsta s nadmorskom visinom. Analiza florističke sličnosti potvrdila je postojanje osam diskretnih visinskih šumskih pojaseva na primorskim Dinaridima te jasnu florističku razdjelnicu između mediteranske na nižim i eurosibirsko-sjevernoameričke fitogeografske regije na višim nadmorskim visinama. Šumska vegetacija ekološki je uvjetovana prvenstveno klimatskim gradijentima srednje godišnje temperature i precipitacije, te gradijentima karakteristika supstrata (pH reakcije i količine kalcijeva klorida, količine organske tvari i pokrovnosti listinca). Indikatorske vrijednosti za mahovine imaju slabiji indikatorski potencijal u objašnjavanju florističkog sastava u odnosu na indikatorske vrijednosti za vaskularne biljke, što dokazuje da ove dvije skupine samo dijelom opisuju iste ekološke gradijente.

Abstract (english)

A comparative study of the altitudinal distribution of bryophytes and vascular plants on littoral Dinarides was conducted along two complete, about 1500 m long elevational transects in Gorski Kotar and Sjeverni Velebit. A total of 570 plant taxa were recorded, of which 185 bryophyte species, which makes one fourth of known bryophyte diversity in Croatia. Both groups show similar patterns of alpha diversity, best described by the cubic regression function with diversity maxima approximately between 1100 and 1200 m a.s.l. The total number of taxa of vascular plants and bryophytes is the lowest in the lowest belt of holm oak, and the highest in the complex of spruce communities. High number of taxa and intra-belt beta diversity of the vascular flora in the belts of oriental hornbeam and European hop-hornbeam is a result of the long-lasting intensive degradation of these forests, which has enabled the establishment of a large number of non-forest taxa. Vascular plants exhibit the highest species turnover on the border of two phytogeographical regions, while the most prominent species turnover of bryophytes appears with evergreen boreal and subalpine vegetation types. Bryophytes exhibit wider altitudinal ranges and a greater tendency toward exclusively higher elevations compared to vascular plants. Neither vascular plants nor bryophytes follow Rapoport’s rule of increment of the average altitudinal range of species with increasing elevation. The analysis of floristic similarity confirmed the existence of eight discrete altitudinal forest belts in the littoral Dinarides and a clear floristic division between the Mediterranean region in the lower and the Euro-Siberian-North American phytogeographical regions at higher altitudes. Forest vegetation is ecologically primarily defined by climatic gradients of mean annual temperature and precipitation, and gradients of substrate characteristics (pH reaction and amount of calcium chloride, the amount of organic matter and litter cover). The indicator values for bryophytes exhibit weaker indicator potential in explaining floristic composition compared to indicator values for vascular plants, which proves that these two groups only partially describe the same ecological gradients.

• Keywords: Gorski kotar; mahovine; nadmorska visina; primorski Dinaridi; raznolikost; Sjeverni Velebit; vaskularne biljke
• Keywords (english): Gorski kotar; bryophytes; elevation; littoral Dinarides; diversity; Sjeverni Velebit; vascular plants
• Language: croatian
• URN:NBN: urn:nbn:hr:217:738657
• Promotion: 2021
• Study programme: Title: Biology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2023-07-09
• Created on: 2021-07-20 07:14:02