Životni ciklus i ekologija glavate želve (Caretta caretta, Linnaeus, 1758) : razvoj i primjena modela dinamičkog energijskog proračuna

After the general introduction presented in Chapter 1, Chapter 2 tackles the problem of disjointed and conflicting data, and explores to what extent do loggerhead turtle populations and life stages differ in morphology. In order to take into account the possible geographic and life stage variability, I study two neighboring populations and all postembryonic life stages by comparing the ratio of carapace length, width and height of sea turtles. I conduct a detailed analysis of empirical models (growth curves, conversion formulae). One of the aims is to answer a somewhat technical question whether or not can the growth of loggerhead turtles be considered isomorphic. Considerable deviations from isomorphy would require additional steps when defining through out the life the acquisition (or use) of energy in relation to the surface area-volume ratio. The focus of Chapter 3 is on developing a full life cycle model of loggerhead turtles. Due to substantial variability present in data related to loggerhead turtles living in different sea basins, I decided to focus on a geographically defined population rather than the whole species. In this chapter the North Atlantic population of loggerhead turtles is analyzed as it has one of the largest nesting aggregations of loggerhead turtles. After estimating the parameter values using the covariation method [126] of the package DEBtool implemented in Matlab, I compare model predictions to observations, and discuss the implications of the results. In Chapter 4 another population of loggerhead turtles, the Mediterranean population, is the main focus, together with the comparison between individuals belonging to the Mediterranean, and individuals belonging to the North Atlantic population. Individuals belonging to the two populations are first compared based solely on their morphology (length, weight, and the ratio of the two) at two life events: hatching and nesting. The average egg size reported for each population is taken into account, as it has been generally reported to account for most of the variation in hatchling sizes. As the next step, I develop a DEB model for the individuals of the Mediterranean population, analyze the model predictions, and discuss the implications of the results. Then I compare the model parameters between the populations, and suggest a physiological (maturity based) explanation for the adults having such markedly different sizes at nesting. In addition, posthatchling growth is analyzed in more detail, expanding the results of the previous chapter which suggested faster growth of posthatchlings than predicted by the model. Lastly, I reproduce a pattern of biphasic growth by modifying the food availability during the first part of the life cycle. Chapter 5 showcases the applications of the DEB model to study the effects of temperature and food availability, and the effects of plastic ingestion on the energy budget and life cycle of the loggerhead turtle. I simulate a realistic range of temperatures and food densities to explore their effect on the energy budget, i.e. observable quantities such as size and reproduction output. I present a mechanism for the effects of plastic ingestion on 6 General introduction the energy budget, applicable to any species for which the DEB parameters are known. I simulate a range of observed amounts of ingested debris, and study their effects on the processes of growth, maturation, and reproduction while assuming the plastic has (a) the same, and (b) several times longer gut residence time compared to that of food. Finally, in Chapter 6 I discuss my results in a broader context, and present an outlook on future studies, applications, and possible expansions of the developed model.Glavate želve (Caretta caretta, Linnaeus 1758) prisutne su u umjerenoj klimatskoj zoni svih svjetskih oceana, evoluirajući u nekoliko populacija i lokalnih subpopulacija. Žive duže od 65 godina, a njihov spol određen je temperaturom inkubacije tijekom zadnje trećine embrionalnog razvoja (koji traje oko dva mjeseca). Tijekom svog života, mogu narasti do veličine čak 25 puta veće od one pri izlijeganju: u prosjeku 4 cm dugačka i 20 g “teška” kornjačica koja izađe iz gnijezda, može postati odrasla jedinka teška preko 100 kg s oklopom dugačkim 100 do 130 cm. Ženke dolaze položiti jaja na istu plažu na kojoj su se izlegle, zbog čega ponekad preplivaju stotine kilometara. Životni ciklus morskih kornjača je dugo vremena bio u grubo podijeljen u tri životna stadija: embrio, seksualno nezrele (juvenilne) jedinke, i odrasle (adultne) jedinke. Iako je provedeno mnogo studija i objavljeno mnogo literature na tematici glavatih želvi i morskih kornjača općenito, fokus određene studije je najčešće bila određena karakteristika ili određen životni stadij. Odabrala sam teoriju dinamičckog energijskog proračuna (eng. Dynamic Energy Budget, DEB) kao stazu koja će me dovesti do mog “Svetog Grala”: DEB modela glavate želve. Pristup ove teorije je sveobuhvatan: praćenje zakona termodinamike, nekoliko tipova homeostaze (ravnoteže) koju svaki sustav (od stanice preko jedinke do ekosustava) pokušava postići i održati, utjecaj hrane i temperature na energijski proračun, međuovisnost energijskog proračuna i procesa kao što su rast, održavanje, sazrijevanje,i reprodukcija. Dodatno, DEB teorija bila je i ostala jedna od najbolje razrađenih i dosljednih dostupnih teorija

Morphological and genetic features of crayfish species Austropotamobius torrentium (Schrank, 1803) from Žumberak – Samoborsko gorje Nature Park

Potočni rak (Austropotamobius torrentium) jedna je od četiri autohtone vrste rakova porodice Astacidae na području Hrvatske, a nastanjuje hladnije potoke na višim nadmorskim visinama. Filogenetički odnosi unutar populacija ove vrste još nisu potpuno razjašnjeni. U ovom diplomskom radu ispituju se morfološka obilježja i filogenetički odnosi 61 jedinke (37 mužjaka i 24 ženke) prikupljene na devet lokacija na području Parka prirode Žumberak – Samoborsko gorje. Molekularno filogenetičke analize provedene su na mitohondrijskim genima za 16S rRNA i podjedinicu I citokrom oksidaze (COI). Izračunata je genetička udaljenost među sekvencama, a kako bi se dobili filogrami, izolirane sekvence su Bayesian analizom korelirane međusobno i sa sekvencama potočnog raka iz drugih dijelova Hrvatske i Europe te sekvencama preuzetima iz internetske baze podataka. Izračunato je vrijeme razdvajanja prema mithondrijskom genu za COI. Također, izmjerene su 23 morfometrijske i pet merističkih značajki, koje su zatim grupirane prema rezultatima genetičkih analiza i uspoređene statističkim testovima. Dobiveni rezultati pokazali su vrlo veliku genetičku raznolikost potočnih rakova na području PP Žumberak-Samoborsko gorje. Populacije se mogu odijeliti u četiri genetički distinktivne haplogrupe (Dunav, Gorski Kotar, Zeleni Vir i Žumberak/Plitvice/Bjelolasica), a njihovo naseljavanje ovog dijela Europe nakon Pleistocenskih ledenih doba rekonstruirano je pomoću vremena razdvajanja i genetičkih udaljenosti među populacijama. Statističkom obradom izmjerenih morfoloških vrijednosti uočene su značajne razlike među geografski odijeljenim populacijama, a diskriminantnom analizom izdvojena su obilježja koja su zatim omogućila vrlo visok postotak točne klasifikacije. Kako razlike među jedinkama iz različitih populacija nisu vidljive na prvi pogled nego tek nakon multivarijantne diskriminantne analize, vrlo je vjerojatno da se radi o tzv. kriptičnim vrstama/podvrstama. Velika genetička raznolikost i morfološka varijabilnost populacija potočnih rakova na području Parka prirode Žumberak – Samoborsko gorje zahtijevat će u neposrednoj budućnosti i posebnu brigu u vidu zaštite i održanja ovog jedinstvenog biološkog fenomena na Europskoj razini.The stone crayfish (Austropotamobius torrentium) is one of four native Croatian crayfish species that inhabits mainly cold brooks on higher altitudes. Phylogenetic relationships among different populations of this species are not yet completely resolved. In this research we have studied morphological characteristics and phylogenetic relationships of 61 individuals (37 males and 24 females) that have been collected from nine sites situated in Žumberak - Samoborsko gorje Nature Park. For molecular phylogenetic analyses we used mitochondrial genes for large ribosomal unit (16S rRNA) and for subunit I of citocrom oxidase (COI). Sequence divergences and nucleotide diversity were calculated and Bayesian analysis was applied for constructing filogenetic trees and correlating these sequences with sequences of stone crayfish from other parts of Croatia and Europe and those retrieved from on-line data-bases. Time of divergence was calculated according to the molecular clock for mitochondrial COI gene. In morphological aspect of research we measured 23 morphometrical and five meristic characteristics, which were then grouped in accordance with the results of previous genetic analyses and processed with statistical methods. Obtained results show a large genetic diversity of populations of stone crayfish in the area of Žumberak – Samoborsko gorje Nature Park. Populations can be divided into four distinctive haplogroups (Dunav, Gorski Kotar, Zeleni Vir and Žumberak/Plitvice/Bjelolasica), and the colonization of these part of Europe that followed the Pleistocenic ice ages can be retraced by consulting times of divergence and genetic diversity. Statistical analyses of morphological data shows significant differences for geographically separated populations, and discriminant analysis yielded a very high percent of correct classifications. However, since these differences were apparent only after grouping and statistically analizing the data, it is possible that this is a case of cryptic species/subspecies. Such high genetic diversity and morphological variation in populations of stone crayfish in Žumberak – Samoborsko gorje Nature Park represents an unique phenomenum on the European scale and will demand special care and protection in the near future

Morphological and genetic features of crayfish species Austropotamobius torrentium (Schrank, 1803) from Žumberak – Samoborsko gorje Nature Park

Potočni rak (Austropotamobius torrentium) jedna je od četiri autohtone vrste rakova porodice Astacidae na području Hrvatske, a nastanjuje hladnije potoke na višim nadmorskim visinama. Filogenetički odnosi unutar populacija ove vrste još nisu potpuno razjašnjeni. U ovom diplomskom radu ispituju se morfološka obilježja i filogenetički odnosi 61 jedinke (37 mužjaka i 24 ženke) prikupljene na devet lokacija na području Parka prirode Žumberak – Samoborsko gorje. Molekularno filogenetičke analize provedene su na mitohondrijskim genima za 16S rRNA i podjedinicu I citokrom oksidaze (COI). Izračunata je genetička udaljenost među sekvencama, a kako bi se dobili filogrami, izolirane sekvence su Bayesian analizom korelirane međusobno i sa sekvencama potočnog raka iz drugih dijelova Hrvatske i Europe te sekvencama preuzetima iz internetske baze podataka. Izračunato je vrijeme razdvajanja prema mithondrijskom genu za COI. Također, izmjerene su 23 morfometrijske i pet merističkih značajki, koje su zatim grupirane prema rezultatima genetičkih analiza i uspoređene statističkim testovima. Dobiveni rezultati pokazali su vrlo veliku genetičku raznolikost potočnih rakova na području PP Žumberak-Samoborsko gorje. Populacije se mogu odijeliti u četiri genetički distinktivne haplogrupe (Dunav, Gorski Kotar, Zeleni Vir i Žumberak/Plitvice/Bjelolasica), a njihovo naseljavanje ovog dijela Europe nakon Pleistocenskih ledenih doba rekonstruirano je pomoću vremena razdvajanja i genetičkih udaljenosti među populacijama. Statističkom obradom izmjerenih morfoloških vrijednosti uočene su značajne razlike među geografski odijeljenim populacijama, a diskriminantnom analizom izdvojena su obilježja koja su zatim omogućila vrlo visok postotak točne klasifikacije. Kako razlike među jedinkama iz različitih populacija nisu vidljive na prvi pogled nego tek nakon multivarijantne diskriminantne analize, vrlo je vjerojatno da se radi o tzv. kriptičnim vrstama/podvrstama. Velika genetička raznolikost i morfološka varijabilnost populacija potočnih rakova na području Parka prirode Žumberak – Samoborsko gorje zahtijevat će u neposrednoj budućnosti i posebnu brigu u vidu zaštite i održanja ovog jedinstvenog biološkog fenomena na Europskoj razini.The stone crayfish (Austropotamobius torrentium) is one of four native Croatian crayfish species that inhabits mainly cold brooks on higher altitudes. Phylogenetic relationships among different populations of this species are not yet completely resolved. In this research we have studied morphological characteristics and phylogenetic relationships of 61 individuals (37 males and 24 females) that have been collected from nine sites situated in Žumberak - Samoborsko gorje Nature Park. For molecular phylogenetic analyses we used mitochondrial genes for large ribosomal unit (16S rRNA) and for subunit I of citocrom oxidase (COI). Sequence divergences and nucleotide diversity were calculated and Bayesian analysis was applied for constructing filogenetic trees and correlating these sequences with sequences of stone crayfish from other parts of Croatia and Europe and those retrieved from on-line data-bases. Time of divergence was calculated according to the molecular clock for mitochondrial COI gene. In morphological aspect of research we measured 23 morphometrical and five meristic characteristics, which were then grouped in accordance with the results of previous genetic analyses and processed with statistical methods. Obtained results show a large genetic diversity of populations of stone crayfish in the area of Žumberak – Samoborsko gorje Nature Park. Populations can be divided into four distinctive haplogroups (Dunav, Gorski Kotar, Zeleni Vir and Žumberak/Plitvice/Bjelolasica), and the colonization of these part of Europe that followed the Pleistocenic ice ages can be retraced by consulting times of divergence and genetic diversity. Statistical analyses of morphological data shows significant differences for geographically separated populations, and discriminant analysis yielded a very high percent of correct classifications. However, since these differences were apparent only after grouping and statistically analizing the data, it is possible that this is a case of cryptic species/subspecies. Such high genetic diversity and morphological variation in populations of stone crayfish in Žumberak – Samoborsko gorje Nature Park represents an unique phenomenum on the European scale and will demand special care and protection in the near future

Size scaling in western North Atlantic loggerhead turtles permits extrapolation between regions, but not life stages

Sea turtles face threats globally and are protected by national and international laws. Allometry and scaling models greatly aid sea turtle conservation and research, and help to better understand the biology of sea turtles. Scaling, however, may differ between regions and/or life stages. We analyze differences between (i) two different regional subsets and (ii) three different life stage subsets of the western North Atlantic loggerhead turtles by comparing the relative growth of body width and depth in relation to body length, and discuss the implications. Results suggest that the differences between scaling relationships of different regional subsets are negligible, and models fitted on data from one region of the western North Atlantic can safely be used on data for the same life stage from another North Atlantic region. On the other hand, using models fitted on data for one life stage to describe other life stages is not recommended if accuracy is of paramount importance. In particular, young loggerhead turtles that have not recruited to neritic habitats should be studied and modeled separately whenever practical, while neritic juveniles and adults can be modeled together as one group. Even though morphometric scaling varies among life stages, a common model for all life stages can be used as a general description of scaling, and assuming isometric growth as a simplification is justified. In addition to linear models traditionally used for scaling on log-log axes, we test the performance of a saturating (curvilinear) model. The saturating model is statistically preferred in some cases, but the accuracy gained by the saturating model is marginal

The comparative energetics of the turtles and crocodiles

The Add-my-Pet collection of data on energetics and Dynamic Energy Budget parameters currently contains 92 species of turtles and 23 species of crocodiles. We discuss patterns of eco-physiological traits of turtles and crocodiles, as functions of parameter values, and compare them with other taxa. Turtles and crocodiles accurately match the general rule that the lifetime cumulated neonate mass production equals ultimate weight. The weight at birth for reptiles scales with ultimate weight to the power 0.6. The scaling exponent is between that of amphibians and birds, while that for mammals is close to 1. We explain why this points to limitations imposed by embryonic respiration, the role of water stress and the accumulation of nitrogen waste during the embryo stage. Weight at puberty is proportional to ultimate weight, and is the largest for crocodiles, followed by that of turtles. These facts explain why the precociality coefficient, s bp H-approximated by the ratio of weight at birth and weight at puberty at abundant food-decreases with ultimate weight. It is the smallest for crocodiles because of their large size and is smaller for turtles than for lizards and snakes. The sea turtles have a smaller s bp H than the rest of the turtles, linked to their large size and small offspring size. We link their small weight and age at birth to reducing risks on the beach. The maximum reserve capacity in both turtles and crocodiles clearly decreases with the precociality coefficient. This relationship has not been found that clearly in other taxa, not even in other reptiles, with the exception of the chondrichthyans. Among reptiles, crocodiles and sea turtles have a relatively large assimilation rate and a large reserve capacity