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Title:Ecological niche relations of indigenous and invasive crayfish (Astacoidea) in Slovenia
Authors:Jaklič, Martina (Author)
Brancelj, Anton (Mentor) More about this mentor... New window
Files:.pdf Martina_Jaklic.pdf (4,73 MB)
 
Language:English
Work type:Doctoral dissertation (mb31)
Tipology:2.08 - Doctoral Dissertation
Organization:FPŠ - Graduate School
Abstract:In this study, realised and fundamental niches were combined between studied ICS (Austropotamobius torrentium (Schrank, 1803), Austropotamobius pallipes (Lereboullet, 1858), Astacus astacus (Linnaeus, 1758)) and NICS (Pacifastacus leniusculus (Dana, 1852), Orconectes limosus (Rafinesque, 1817), Cherax quadricarinatus (von Martens, 1868)). The realised niche was described by population characteristics. P. leniusculus showed similar annual cycle than ICS, but on the other hand it showed higher population density, shorter breeding period, and better individual condition (estimated with SMI) comparing to the ICS. These are its advantages over ICS, which increase its potential for the invasiveness. The most pronounced this threat is to A. astacus, with which it has the most similar/ overlapping realised niche. Similar was observed comparing the ICS and NICS fundamental niches presented by selected physiological measurements (maximal food (Cmax) and oxygen consumption (Rn), concentration of haemocyanin in haemolymph (Hc), electron transport system (ETS) activity and potential growth scope (PGS). As a result of higher plasticity and adaptation to varied environmental conditions, NICS expressed different physiological response to temperature at cellular (ETS activity) and organism (Cmax, Rn, PGS) level. Similar fundamental characteristics (expressed with thermal optimums) were found between P. leniusculus and ICS, while optima for O. limosus and C. quadricarinatus were more narrow and higher (above 22 °C and 30 °C). Modelling of thermal niches showed differences mostly among species on cellular level (in ETS activity). This was a new approach and support for better estimation of success and proliferation of new invaders. Furthermore, C. Quadricarinatus, found for the first time as established population in temperate climate of Europe (in Slovenia in 2009), was used in this study, as a model organism, to show that the combination of fundamental and realised thermal niche, as well as ecophysiological and field research can constitute an important input to the model for estimating the risk associated with C. quadricarinatus. It is rarely possible to observe the development of new invaders in the new environment, therefore monitoring of the C. quadricarinatus through the three growth period (1-lag phase, 2-log phase, 3-stable phase), was unique example in the invasive biology. After extremely increasing the population in 2011 and 2012 (for 7.7 - 10.1 % per month) the population developed and stabilised in March 2012. Based on these high numbers of field and lab data, the TIRI (Thermal Invasive Risk Index) was developed to produce instant results that may be satisfactory for evaluation of different degrees of invasiveness. We found that the oxbow lake Topla had no lethal days (no. of days when water temperature is below or above temperature of death) in comparison with the adjacent rivers where the number of lethal days probably constitutes an important barrier for species spreading. Therefore, we concluded that C. quadricarinatus could potentially reproduce in the adjacent rivers, but survival of the brood is doubtful, especially due to previous results concerning critical min/max temperatures.
Keywords:potočni raki, jelševec, koščak, koščenec, signali rak, trnavec, rdečeškarjevec, sezonska dinamika, termalna toleranca, temeljna ekološka niša, realizirana niša, potencialna invazivnost
Year of publishing:2016
Source:Nova Gorica
COBISS_ID:3984207  Link is opened in a new window
URN:URN:SI:UNG:REP:FWQIPMH2
Views:3327
Downloads:271
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Secondary language

Language:Slovenian
Title:Ekološka razmerja niš avtohtonih in invazivnih vrst potočnih rakov (Astacoidea) v Sloveniji
Abstract:V raziskavi smo primerjali realizirane in temeljne ekološke niše med izbranimi domorodnimi vrstami (koščak - Austropotamobius torrentium (Schrank, 1803), koščenec - Austropotamobius pallipes (Lereboullet, 1858) in jelševec - Astacus astacus (Linnaeus, 1758)) in tujerodnimi vrstami potočnih rakov (signalni rak - Pacifastacus leniusculus (Dana, 1852), rak trnavec - Orconectes limosus (Rafinesque, 1817) in rdečeškarjevec - Cherax quadricarinatus (von Martens, 1868)). Realizirana niša je bila opredeljena s populacijskimi karakteristikami. Ugotovili smo, da imajo signalni rak in domorodne vrste potočnih rakov podoben letni življenjski cikel, vendar ima signalni rak nekatere značilnosti (populacija z visoko gostoto, krajši razvojni krog, boljši fitnes), ki ga postavljajo v boljši položaj v primerjavi z domorodnimi vrstami in povečujejo možnosti, da postane invaziven. To je najbolj izrazito v primerjavi z jelševcem (A. astacus), s katerim imata močno prekriti realizirani niši. Podobno prekrivanje smo prepoznali pri primerjanju temeljnih ekoloških niš, kjer so imele domorodne vrste zelo podobne niše kot signalni rak, med tem kot smo manj podobnosti opazili pri raku trnavcu (O. limosus) in tropskem rdečeškarjevcem (C. quadricarinatus). Tujerodne vrste so kot rezultat plastičnosti in visoke adaptabilnosti na različna okolja pokazale drugačen fiziološki odziv kot domorodne vrste, in to tako na organizemskem nivoju (maksimalna poraba hrane in kisika ter potencialni prirastek), kot tudin na celičnem nivoju (ETS aktivnost), kjer je bil le ta še bolj izrazit. Prikaz temeljne ekološke niše s fiziološkimi parametri je popolnoma nov pristop k boljšemu razumevanju in ocenjevanju invazivnosti novih vrst. Za to smo uporabili raka rdečeškarjevca (C. quadricarinatus) kot modelni organizem, s katerim smo povezali realizirano in temeljno ekološko nišo in s tem prikazali uporabnost eko-fizioloških in terenskih raziskav v razvoju modela, ki lahko oceni potencialno nevarnost živali v novem okolju. Rak rdečeškarjevec je bil kot nova tujerodna vrsta prvič najden v Evropi oz. v Sloveniji v letu 2009. V splošnem so redki primeri, pri katerih je možno spremljati celoten razvoj kolonizacije tujerodnih organizmov od vnosa pa do vzpostavitve stabilne populacije. Zato je ta raziskava unikatna, saj smo rdečeškarjevca spremljali od rasti, ko populacija ni rastla, preko faze ekstremne rasti (od 2011 do februarja 2012) pa do faze stabilizacije (marec 2012) brez naraščanja populacije (1-lag faza, 2-log faza, 3-stabilna faza). Zaradi veliko terenskih in fizioloških podatkov smo razvili poseben indeks TIRI (angl. Thermal Invasive Risk Index), ki omogoča hiter rezultat, oz. oceno potencialne invazivnosti živali (v tem primeru raka) v novem okolju. Iz naših rezultatov je bilo razvidno, da je potencialen habitat za obstoj populacije rdečeškarjevca le mrtvica Topla, ki praktično nima letalnih dni (ko temperature vode pade po 7 °C), med tem ko imajo okoliške reke precej več takšnih dni v letu in je preživetje (predvsem zaroda) v njih vprašljivo. Netoleranca nizkih temperatur predstavlja pomembno naravno pregrado, ki preprečuje, da bi se rdečeškarjevec razširil v okoliške vode. Zaključili smo, da je v prihodnje nujno potreben razvoj ekofizioloških metod, ki omogoča hiter in zanesljiv rezultat, za lažjo oceno invazivnosti ali nevarnosti novih vrst, ki redno prihajajo v naš prostor.
Keywords:Astacus astacus, Autropotamobius torrentium, Autropotamobius pallipes, Pacifastacus leniusculus, Orconectes limosus, Cherax quadricarinatus, seasonal dynamics, thermal tolerance, fundamental niche, realised niche, potential invasiveness


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