Kolora, S.R.R. & Weigert, A. & Saffari, A. & Kehr, S. & Beatriz, M. & Costa, W. & Spröer, C. & Indrischek, H. & Chintalapati, M. & Lohse, K. & Doose, G. & Overmann, J. & Bunk, B. & Bleidorn, C. & Grimm-Seyfarth, A. & Henle, K. & Nowick, K. & Faria, R. & Stadler, P.F. & Schlegel, M. (2018) -
Divergent evolution in the genomes of closely-related lacertids, Lacerta viridis and L. bilineata and implications for speciation. - GigaScience, giy160. https://doi.org/10.1093/ gigascience/giy160 
× Background Lacerta viridis and L. bilineata are sister species of European green lizards (eastern and western clades respectively), which until recently were grouped together as the L. viridis complex. Genetic incompatibilities were observed between lacertid populations through crossing experiments, which led to the delineation of two separate species within the L. viridis complex. The population history of these sister species and processes driving divergence are unknown. We constructed high quality de novo genome assemblies for both L. viridis and L. bilineata through Illumina and PacBio sequencing, with annotation support provided from transcriptome sequencing of several tissues. To estimate gene flow between the two species and identify factors involved in reproductive isolation, we studied their evolutionary history, identified genomic rearrangements, detected signature of selection on non-coding RNA and protein-coding genes. Findings Here we show that the gene flow was primarily unidirectional from L. bilineata to L. viridis after their split at least 1.15 Mya. We detected positive selection of the non-coding repertoire; mutations in transcription factors; accumulation of divergence through inversions; selection on genes involved in neural development, reproduction and behavior, as well as in UV-response possibly driven by sexual selection, whose contribution to reproductive isolation between these lacertid species need to be further evaluated. Conclusion The combination of short and long sequence reads resulted in one of the most complete lizard genome assemblies. The characterization of a diverse array of genomic features provided valuable insights into the demographic history of divergence among European green lizards, as well as key species differences, some of which are candidates that could have played a role in speciation. In addition, our study generated valuable genomic resources that can be used to address conservation related issue in lacertids.
Fischer, D. & Rehák, I. (2010) -
The Ecology, Ethology and Variability of the European Green Lizard Lacerta viridis, from a Local Population along the River Vltava in Central Bohemia. - Gazella, 37: 50-167. × A population of Lacerta viridis at a locality in Tiché údolí not far from the Prague district of Suchdol was chosen for a study of its ecology, ethology and variability. The lizards inhabit a south facing slope and two abandoned quarries with an area of approx. 5 ha. The estimated population at the locality was between 40 to 60 individuals of which 30 – 35 were adults. Each year the number fluctuated considerably with regards to the changeable proportion of juveniles depending on the reproductive success. Likewise the population’s age structure fluctuated considerably depending on the reproductive success, where the ratio of individuals older than 2 years : under 2 years was roughly 1 : 1 following successful reproduction and 1 : 0.34 in favour of the older individuals following unsuccessful reproduction. The sex ratio in adults was around 1.22 : 1 in favour of the males. Population density was around 11 (6 – 7 adults) individuals per hectare. If the unused areas are removed then it was around 22 (12 – 14 adults) per hectare. During the reproductive period, the lizards aggregated markedly at certain sites in the locality. Adult males with their original tail achieved overall body lengths of 286.0 (323.6) 353.0 mm and weights of 23.5 (38.9) 53.0 g. Adult females with their original tail achieved overall body lengths of 257.0 (291.8) 327.0 mm and a weight of 18.5 (28.2) 37.0 g. For adult males the tail was 1.94 to 2.29 times longer than the body, for females it was 1.86 to 2.47 times longer. Adult males had considerably longer and wider heads in relation to body length and a far longer parietal scale in relation to the length and width of the head than the females. In contrast, adult females had a considerably larger relative spacing of the limbs and a considerably longer frontal scale in relation to the parietal scale than the adult males. Moreover adult males were found to have higher maximum and average numbers of femoral pores and a broader tail base than females. Individuals from the population showed great individuality in numbers and the arrangement of the scales on the dorsal side of the head. The normal arrangement and number of all of these scales was only found in 4 out of the 35 individuals captured, very often various shields were separated from the parts by a deep groove. 9 to 13 cervical collar scales were recorded. In essence, the colouring of the adult males was uniform – the body and legs were distinctly green with a number of small dark spots, the sides often had a yellow tinge, the abdomen was yellowish-green to clearly yellow, often with dark speckling. The tail was most often the same colour as the body, the head was dark on top with distinct light speckling. The throat, lower jaw and the lateral parts of the head were light blue to greenish-blue, during reproduction, however, this colouring gained in intensity. The throat colouring always ended abruptly at the cervical collar. In contrast the colouration of adult females varied considerably for each individual and can be divided up into several colour types ranging from a colouration that is more or less the same as that of the adult males, including the blue throat in one case, to variants with a dark dorsal stripe, varying sizes of speckling that always increased in density in the caudal direction to a variant that had uniform brown-green marbling. The tail and the rear legs were, on the whole, dark, the dorsal side of the head was olive green with a dark design, only rarely did it have lighter patches, the throat was most often white, the abdomen greyish-white without patches. After hatching the young were monochromatically grey-brown with a row of white spots on the sides of the body, with a creamy white throat and abdomen. The males acquired the characteristic adult colouration before the 2nd hibernation, the females over the next year in three various manners. For all individuals the brown colouring intensified during growth and dark patches appeared followed by light lines on the sides of the body. Gradual greening then began either from the dorsal side of the body, thus in the interphase an individual had a green back and brown hips or, conversely on the sides of the body, thus in the interphase the individual had a brown back and green sides. The last possibility was a gradual breakdown of the brown colouring, it being replaced by green on the entire body, thus the individual had brown-green marbling in the interphase. 62 % of the adult males from the locality had a tail in varying stages of regeneration. For adult females and juveniles this percentage was much lower, that being 18 % for adult females and 6 % for juveniles. The length of the regenerated tail is demonstrably less than that of the original tail. During regeneration there were changes in both its structure and its colouring. An increased incidence of other injuries was recorded in adult males. These included missing parts of the digits, various scars on the body and very frequent abrasions on the head. From the moment the adult females took part in their first mating there was a clear deformation of the scales in the area above the rear limbs caused by the males during copulation. The winter shelters were abandoned at the start of March to mid April depending on the temperature and weather, i.e. during sunny weather and at temperatures above 9 °C. With a gradual warming the adult males were the first to leave the shelter followed shortly afterwards by the sub-adult individuals with nearly a month’s interval before the adult females left. During a sudden warming, individuals of both sexes appeared in all age groups almost simultaneously. Winter shelters were sought and the start of hibernation began when the temperature fell below approx. 16 °C either in the second half of September or up to the first half of October. The young were active by up to 20 days longer than the adults and sub-adults. Within the entire population, hibernation took place en masse in two sites of the locality. The first male ecdysis was the signal to start mating (female ecdysis did not play any role). During favourable weather some of the females in the population mated immediately after laying the first clutch of eggs. The first mating took place during May, during unfavourable weather it was extended to the first half of June, the second mating was during June. In favourable weather mating lasted roughly a week, in unfavourable conditions (rain, cold) it was prolonged to roughly a month. After 19 to 41 days of pregnancy the eggs were laid – in June to the start of July for the first clutch, during July for the second clutch. Incubation ranged from 69 to 86 days. Hatching took place from September to the start of October. The young from the second clutch were first observed on the surface after the hibernation period. After a wet and cold year none of the young survived. The course of the annual cycle, starting with leaving the winter shelters and the first adult male ecdysis followed by the mating season, egg laying and ending with seeking winter shelters is exceptionally synchronised in the population under study. At the start and end of the period of activity the lizards were active during the day roughly from noon to 5 p.m., for the rest of the period of activity from 9.30 a.m. to 7 p.m., at temperatures above 17°C activity was extended to beyond 8 p.m. At the start of the period of activity (April and May) juveniles left the night shelter about 1 – 1.5 hours before the adults and sub-adults. The optimum temperatures at which the largest number of active individuals was found on the surface during sunny weather ranged from 19 °C to 24 °C. On sunny days with temperatures above 28°C the lizards sought shelter or kept to the shadows in the vegetation. The lowest temperature at which an individual was found to be active was 9 °C during sunny weather and 13 °C when overcast. On days that did not have a maximum temperature of 25 °C, activity was unimodal, peaking between 10 a.m. and 2 p.m., at temperatures above 25 °C it was bimodal with a fall in activity roughly between 2 p.m. and 5 p.m. Pregnant females were even active under conditions in which the other individuals did not leave the shelter (in an extreme case at 13 °C with light rain), however, on average, they sought night shelter sooner. During the period of activity the majority of the adults and all of the juvenile individuals dispersed to more or less permanent individual home ranges. A minority of the adult males and all of the sub-adults did not have permanent ranges and lived an itinerant life during the period of activity. The size of the home ranges varied considerably per individual and fluctuated markedly depending on the part of the period of activity the individual was in. In 1995 its range was 5 m2 (62.9 m2) 225 m2 for adult males and 18 m2 (60.0 m2) 186 m2 for adult females, in 1996, when the weather was exceptionally bad, its range was 37 m2 (489.4 m2) 2023 m2 for adult males and 13 m2 (80,3 m2) 313 m2 for adult females. The adult males used the largest home ranges, that being in the period preceding the first mating and the first mating period, especially those that did not manage to obtain a female. The smallest home ranges were recorded for females during pregnancy and males during female pregnancy. It was common for the lizards’ home ranges to overlap, both those of adult males and females. For the large majority of the individuals there was at least one change to the home range during the period of activity, after the mating period the majority of adult males switched to an itinerant lifestyle. After hibernation the lizards had a tendency to occupy the same home range as in the previous year. Within an inhabited home range and outside of it the lizards moved in the proximity of potential shelters, surfaces with no place to hide, such as stony areas and various areas with no vegetation, were consistently avoided. The area of the home range was not used equally. Crannies between stones and tree roots were used as permanent shelters, as were the spaces under large stones or, if needs be, rodent burrows. Various dense, often thorny, bushes were used occasionally. The lizards often clambered up various trees and bushes. During the mating period the lizards formed permanent pairs sharing their home ranges for this period. Over the course of roughly a week they copulated several times over. In this period the males defended their territory very ardently, sometimes forming displays on their borders and any source of acoustic stimuli was thoroughly checked. Those males that had not formed a permanent couple either inhabited a very large home range that often distinctly overlapped with the home ranges of several other males (or pairs) or they wandered over the entire locality. Both these “kinds” of males constantly tested the readiness of those males living with a female and sometimes they managed to mate with a female. The largest number of conflicts occurred between the males during the mating period. During inclement weather the lizards were not able to form permanent pairs and on occasion the females clearly mated with a greater number of males. Copulation was always preceded by complicated precopulatory behaviour that lasted up to 2.5 hours and involved characteristic elements such as sunbathing together, pursuing the female, mounting the female, sniffng the female on the nape of the neck and in the hip area and even biting the female on the tail, body and nape. The female often dragged the male several tens of centimetres as he bit into her tail. A very characteristic female display is circling with one limb or both front limbs asynchronously. This behaviour was even observed in males during averse behaviour by the female. Acoustic displays by the males were also observed (hissing). During copulation, which lasted several seconds up to a minute, the males grasped the females in the area above the hind legs either from above, as with pincers, more often from the side across the back and abdomen. After the mating period ended the majority of males left the pair, however with a second mating they always returned to the same female. Adult males were very intolerant of one another and during the reproductive period, there were many conflicts between them. The vast majority of these are characterised by a rapid lunge followed by a short chase without any real physical contact. In those cases where the individual under attack did not flee, there was an intense flght,which was preceded by brief displays characterised by inflating the throat, lateral flattening of the body, raising up on the front limbs, bowing the head, whipping movements of the tail and swift circling of the limbs. During these displays the males turned their sides to one another and circled one another. A characteristic trait of the actual flight was grabbing the opponent by the head followed by pushing one another around for various time periods. The flight always ended in a brief chase. No displays of aggression were observed between the females or the young nor was there any aggression to the slow-worms and sand lizards that lived in the locality. Upon hatching the young were 83 mm – 85 mm in total length and weighed around 1 g. After 12 months of growth (without the hibernation period), i.e. aged about 21 months the lengths of these individuals (324 mm for males, 291 mm for females) approached the average values for adults, whilst the heaviest of them (17 g) achieved only 44 % (males) or 59 % (females) of the average adult weight. The lizards first reproduced after the third hibernation, i.e. in their third year. During the first 12 months of postnatal development of the young (without the hibernation period) a positive allometric tail growth was found compared to body length growth, there was negative allometric growth in the length of the head compared to the body length and negative allometric growth in head width compared to the growth in body length. The lizards reacted to the threat of danger in several various ways. The most common was flight that being either directly to a shelter or often just hiding in the vegetation. During their flight the lizards often stopped, a characteristic behaviour was to turn sharply after stopping. Some of the individuals relied on their camouflage colouring and remained motionless on the spot – this behaviour was relatively characteristic for pregnant females. During a direct threat, the lizards defended themselves by biting, which was preceded by a threatening behaviour with open jaws accompanied by relatively loud hissing. During a confrontation with a smooth snake the characteristic reaction was a lightning fast escape from its reach, for one individual this was preceded by a relatively high jump. The lizards spent the majority of the day sunning themselves, often in the same places. In the vast majority of cases, they sunbathed at a distance of less than 50 cm from a potential shelter. The females were more often found further from a shelter than the males as they are less noticeable due to their cryptic colouring. Juveniles were observed sunbathing with their front and hind limbs raised above the ground. The time the lizards spent looking after their body covering was negligible, the dominant part was behaviour associated with ecdysis, then cleaning the parts around the jaws and the nostrils using the tongue or rubbing against the ground or vegetation (always after devouring its prey) and scratching using the rear limbs. Over the active period there were three ecdyses in adults. The ecdysis took three to four days and was a wholly passive affair on the part of the lizards. The dominant component of the lizards’ diet in spring was spiders, millipedes, pill-bugs, worms and larvae or cocoons from various insect species, in the summer and autumn they ate grasshoppers and locusts. Throughout the year they hunted various beetles, crane flies, bee-flies, flesh-flies and on rare occasions even aposematic coloured prey such as wasps and bugs from the genus Pyrrhocoris. Two basic means of acquiring food were observed; those being active searching and the sit & wait strategies. The first of these was, to a great extent, only observed in a short period after leaving the winter shelter, for the rest of the active period the sit & wait strategy clearly dominated. Comparing the data obtained from the study with that of the literature, it emerges that:- The lizards in the population under study clearly had smaller dimensions than those discovered by other authors in other parts of the extended area.- The number of scales on the cervical collar and femoral pores were in the range presented by other authors. In contrast to some Czech authors, the observed number and arrangement of scales on the dorsal side of the head had a far greater variability.- The colouring of the adults in the observed population was in the range of variability presented in the literature. The colouring of newborn young corresponded to the species Lacerta viridis. The changes in colouring during the postnatal development of the young are in agreement with the literature. In addition, a variant was found in which the brown colouring gradually breaks down to be replaced by green on the entire body.- The observed weights and sizes of the young upon hatching are in agreement with the data in the literature. The data on the growth of the young is closest to the results obtained in a study of a population in the nearby city of Brest.- The data on attaining sexual maturity agrees with the results obtained from the Ukrainian Carpathians and from a locality in Brest and differs from the data of certain Czech authors.- The phenological data obtained is considerably close to the results obtained in a population from southern France, from the area above Odessa, the Ukrainian Carpathians and the Rhineland, in contrast it differs relatively markedly from data published from the Czech Republic. As concerns the lizards’ relationship to temperatures, these results are closest to the data from the Rhineland and differ quite markedly from that of Czech authors.- In contrast to the majority of authors, it was found that the females laid two clutches a year, which was only observed by authors studying a population in France.- Compared to Czech authors the observed period of pregnancy was markedly shorter. However the results are almost identical with data obtained from the Rhineland and French populations.- The incubation period was in the range given by the majority of authors.- Overall, the observed daily activity agreed with the published data. In relation to temperatures the results were closest to those from the Rhineland, compared to the other authors, however, the population under study is distinctly more cryophilic. - The observed sex ratio is close to the results from France and the Rhineland, however, it differs from some of the data in the Czech Republic (e.g. Krivoklátsko).- The data obtained on the age structure and its fluctuation in relation to the weather agrees with the data in the literature.- The observed sizes of the home ranges cannot be compared to the cited authors because, for instance, their work does not include the marked fluctuation in the size of the home ranges over the course of the period of activity that was observed in this population.- In principle, the observed data on reproductive behaviour agrees with the published data. Moreover, certain aspects were found that were not looked into by the given authors.
Fischer, D. & Rehák, I. (2010) -
Ekologie, etologie a variabilita ještěrky zelené, Lacerta viridis, z povltavské lokální populace ve středních Čechách. - Gazella, 37: 50-167. × Údolí Vltavy ve středních Čechách se krajinným rázem výrazně odlišuje od okolní krajiny. Vyznačuje sespecifickýmteplotním,vodnímavzdušnýmrežimemazvláštnostmigeologickéhopodkladu. Je domovem typických rostlinných a živočišných společenstev vázaných na charakteristický komplex ekosystémů spojený s hluboce zaříznutým říčním údolím (tzv. říční fenomén – blíže viz Ložek 1988). Výrazná urbanizace a další antropogenní vlivy zdejší původní plně rozvinutý říční fenomén ovšem vý- razně narušily.
Na území pražské zoologické zahrady v Troji se cenná společenstva svázaná s říčním fenoménem díky zvláštnímu režimu územního využití zachovala v pozoruhodné míře. Projevuje se to i unikátními, říčním fenoménem podmíněnými výskyty teplomilných živočichů. Jejich nápadnými a z hlediska ochra- nářského významnými reprezentanty jsou v České republice kriticky ohrožené druhy plazů – užovka podplamatá a ještěrka zelená. Pro zajištění jejich účinné ochrany na území Zoo Praha je potřebné zís- kat řadu údajů z autekologie místních populací. Zatímco výzkum užovky podplamaté zde již po ně- kolik let probíhá, ucelenější údaje o ještěrce zelené z teritoria zoologické zahrady nemáme k dispozici žádné. S výjimkou příspěvku Peciny (1993), nahodilých pozorování a alarmujících informací od pamět- níků o úbytku ještěrek zelených oproti stavu před několika desetiletími. Vysvětlován bývá někdy pre- dací volně se pohybujících pávů. Daleko pravděpodobnější však je souvislost se změnami zahradnic- kého managementu na území zoo, jak nasvědčuje i pozorování Peciny (1993).
Zásadní význam pro pochopení populační dynamiky lokální populace ještěrky zelené v Zoo Praha a stanovení vhodného ochranného režimu mají výsledky výzkumu populace ještěrky zelené z protileh- lého břehu Vltavy, které byly provedeny v rámci diplomové práce prvního z autorů stávajícího sdělení (Fischer 1998), vzniklé na přírodovědecké fakultě Univerzity Karlovy v Praze v rámci výzkumné spolu- práce Přírodovědecké fakulty UK a Zoo Praha pod vedením druhého z autorů. Značnou roli zde mo- hou sehrát i zkušenosti s následným cíleným managementem této lokality, který vedl k výraznému posílení lokální populace, což v současnosti vyhodnocujeme opakovaným ekologickým výzkumem. Opatření jsou na lokalitě realizována prvním z autorů kontinuálně od roku 1999, přičemž finančně je postupně zajišťuje Okresní úřad Praha – západ, MŽP ČR (Program péče o krajinu) a Krajský úřad Stře- dočeského kraje (zákonná péče o místní zvláště chráněné území). V předkládaném sdělení podáváme přehled základních výsledků komplexně pojaté studie této povltavské lokální populace ještěrky zele- né, zabývající se jak její autekologií, etologií a reprodukční biologií, tak i zhodnocením vnější morfo- logie a zbarvení. Ještěrka zelená, Lacerta viridis (Laurenti, 1768) patří k největším a nejznámějším evropským zástup- cům čeledi Lacertidae. Tento druh je součástí komplexu taxonů druhové a poddruhové úrovně, ozna- čovaného jako „zelené ještěrky“, kam je v současnosti, vedle Lacerta viridis, řazeno ještě několik dal- ších, mnohdy navíc polytypických druhů (Elbing et al. 1997). Jedná se o evolučně mladé, morfologicky mnohdy dosti podobné formy, jejichž klasifikace ještě není úplně ustálená, Donedávna byl vlastní druh Lacerta viridis široce pojat – s rozšířením v širokém pásu Evropy mezi atlantickým pobřežím na západě (severní Španělsko, západní Francie, Channel Islands), pobřežím Středozemního moře na jihu a Černo- mořím na východě (na severovýchodě do Podněpří, na jihovýchodě v severozápadním Turecku). Ve střední Evropě se na sever od souvislého areálu rozšíření vyskytuje i izolovaně na příhodných lokali- tách v povodí Labe a Rýna (Mikátová et Nečas 1997, Naulleau 1997). Zjištění o odlišných adaptivních jednotkách v rámci tohoto areálu, hybridizační pokusy a následně vyšetření molekulárními a genetic- kými metodami a fylogeografické analýzy vedly k rozlišení dvou sesterských biologických druhů a te- dy rozdělení stávajícího široce pojímaného druhu Lacerta viridis s. l. na druhy Lacerta bilineata Daudin, 1802 a Lacerta viridis s. str. (Rykena 1991, Amann et al. 1997, Elbing et al. 1997, Brückner et al. 2001, Jo- ger et al. 2001, Godinho et al. 2005, Böhme et al. 2006, Joger et al. 2007).
Západoevropské populace (Velká Británie, Španělsko, Francie, Švýcarsko, Itálie, Andora, Monako, San Marino) připadly druhu Lacerta bilineata, na území Chorvatska, Slovinska a Německa se v současnosti vyskytují oba druhy (v Německu Lacerta bilineata v Porýní a Lacerta viridis v Braniborsku) a populace ze zbytku bývalého areálu rozšíření ještěrky zelené (ČR, SR, Maďarsko, Rakousko, Ukrajina, Balkán) pak zůstávají druhu Lacerta viridis (Amann 1997, Elbing et al. 1997). Ve skutečnosti může být situace ješ- tě poněkud komplikovanější a názory na fylogeografii komplexu zelených ještěrek jsou stále ve vývoji (Böhme et al. 2006a, Joger et al. 2007).
Lacerta viridis a L. bilineata jsou morfologicky a barevně velmi těžko odlišitelné (Gűnther 1996) a přes- tože lze mezi nimi zaznamenat drobné rozdíly ve folidóze a proporcích těla, v konkrétních případech je využití těchto znaků pro určení jednotlivých druhů problematické, neboť individuální variabilita je větší než statistické mezidruhové rozdíly (Elbing et al. 1997). Jediným spolehlivým vnějším znakem pro rozlišení Lacerta viridis a L. bilineata jsou zřetelné rozdíly ve zbarvení novorozených mláďat (Ryke- na 1991, Rykena et al. 1996 a, b).
Přestože z našeho území (Dolnice u Chebu) jsou popsány v rámci střední Evropy vůbec nejstarší (sp. miocén) fosilní doklady formy blízké ještěrce zelené (Čerňanský 2010), je recentní rozšíření ještěr- ky zelené (L. viridis) u nás výhradně výsledkem postglaciální holocenní expanze zelených ještěrek z již- nějších glaciálních refugií (Böhme et al. 2006a). Taxonomicky patří naše ještěrky zelené nominotypic- kému poddruhu (L. v. viridis). V České republice je ještěrka zelená rozšířena na řadě lokalit, spadajících do povodí Dunaje (Morava), které tvoří součást souvislého výskytu tohoto druhu, sahajícího dále na jih a jihovýchod. Vedle toho je známa i z řady lokalit v Čechách z povodí Labe (údolí Berounky, Vltavy, Sá- zavy, Ohře a Labe), které jsou však od souvislého druhového areálu geograficky izolovány a svou exis- tencí jsou úzce svázány s tzv. říčním fenoménem (Ložek 1988, Strödicke 1995). Jejich izolovanost (i když z geologického hlediska nedávná) se odráží i v signifikantní genetické odlišnosti (i v nižší genetické va- riabilitě) ve srovnání s populacemi moravskými (Böhme et Moravec 2005, srv. též Böhme et Berendonk 2005, Böhme et al. 2006b). Konkrétní údaje o výskytu ještěrky zelené na našem území přinášejí např. Prach (1861), Štěpánek (1949), Hanák et al. (1959), Laňka (1965), Opatrný (1973, 1979), Šapovaliv (1980 - nepubl., 1988), Strődicke (1995) nebo Kerouš (1996). Mapku rozšíření v Čechách publikovali např. Lo- žek (1988), Mikátová et Nečas (1997) a Böhme et Moravec (2005).
U nás patří ještěrka zelená mezi kriticky ohrožené druhy a její přežití, hlavně na lokalitách v Čechách, je díky silnému narušení stanovišť nejisté (Baruš et al. 1989, Kerouš 1996, Mikátová et Nečas 1997). Při- tom izolované lokality v Čechách jsou z hlediska dalších výzkumů velmi zajímavé, a to hned z několika důvodů. V první řadě se jedná o lokality, kde ještěrky přežívají na hranici druhových možností, s čímž úzce souvisí i jejich značná zranitelnost. Přitom je pro pochopení ekologických souvislostí velmi cenné a důležité, že české populace obývají namnoze stanoviště původního charakteru. Údaje získané výzku- mem takovýchto populací mají neocenitelný význam při další ochraně druhu. Dále je výzkum izolova- ných populací jako takových, na jehož důležitost poukazují rovněž Elbing et al. (1997), velmi zajíma- vý i teoreticky - poskytuje podklad pro další mezipopulační srovnání s jinými obdobnými populacemi, existujícími např. v Německu, které podrobně zkoumali Böker (1990 a, b) a Elbing (1997) nebo s popu- lacemi ze souvislého areálu rozšíření. České reliktní autochtonní populace mají mimořádnou vědec- kou a konzervačně biologickou hodnotu a vzhledem ke genetické výjimečnosti související s izolova-ností, fragmentací, malou populační početností, genetickým driftem, sníženou variabilitou a možností výskytu unikátních genetických variant vyžadují i speciální metody konzervačního managementu (srv. Böhme et al. 2007, Joger et al. 2010).
Úroveň znalostí o Lacerta viridis z našeho území je zvláště v kontextu s jejich potřebností možno hod- notit jako značně nedostatečnou a útržkovitou, na což mimo jiné upozorňuje i např. Strödicke (1995). Údaje o ní sice přináší např. již Prach (1861), dále pak Štěpánek (1949), Lác (1968), Opatrný (1973) a řa- da dalších autorů, ale ve většině případů se jedná o informace spíše obecného charakteru (mnohdy bez udání zdrojů), které často zcela opomíjejí některé důležité aspekty biologie tohoto druhu. Zajímavé pů- vodní postřehy z ekologie a etologie ještěrky zelené se vyskytují spíše v článcích menšího rozsahu, které se objevují v některých populárnějších přírodovědných časopisech. Jedná se např. o příspěvky Nováka (1954), Houby (1958), Hanáka et al. (1959), Laňky (1965), Vogela (1980) nebo Šapovaliva (1988). Vněj- ší morfologii ještěrky zelené u nás podrobněji zpracovali Šapovaliv (1980 -nepubl.) a Lomičková (1990 – nepubl.), dentici se podrobně věnuje Roček (1980). Řadu poznatků týkajících se ekologie a etologie (hlavně epigamních projevů) pak přináší Šapovaliv (1980 - nepubl., 1988) a Horáčková (1970 – nepubl.). Podrobnější fenologická data jsou k dispozici pouze ze sousedního Slovenska v práci Holece et Kmini- aka (1970). Z výše uvedeného jednoznačně vyplývá naléhavá potřeba studií zaměřených na bližší po- znání všech aspektů biologie Lacerta viridis u nás, což je i cílem námi předkládané práce.
