Vascular flora of Krka National Park (Croatia)

The vascular flora of Krka National Park recorded after its proclamation in 1985 is presented and analysed. In total, 1509 plant taxa within 582 genera and 132 families were recorded. The most represented families are Compositae, Poaceae and Fabaceae, while the dominant chorotypes are south-European and Eurasian. Life-form analysis demonstrated that vascular flora of NP Krka lies between the typical Mediterranean and the central European spectrum, confirming the sub-Mediterranean phytogeographical position of this area. The analyses of medians of ecological indicator values for light, air temperature and soil moisture showed the domination of species typical for open, warm and dry habitats.


Introduction
The Krka River rises in the foothills of the Dinara Mountain about 3.5 km northeast of the town of Knin and is 72.5 km long, including the submerged part of its estuary.Along its course, there are seven systems of tufa barrages with splendid waterfalls, the fundamental natural phenomenon of the national park.Due to the exceptional geomorphological and hydrological values of the Krka River, its course from Nečven and Trošenj fortresses to the Šibenik There are several settlements within the park.
However, contemporaneously with the proclamation of the protection of the area, significant socio-economic changes occurred.The traditional livestock activities, such as raising sheep, goats, donkeys and cows, were rapidly abandoned.The number of livestock in the park is much smaller than it was a few decades ago.In addition, the human population that lived in the area fell greatly for economic reasons as well as because of the hostilities that affected this area during the 1990s.
As a result, the pastureland entered into the process of progressive vegetation succession -it began to be overgrown with bushes, mainly with Juniperus Bridge, including 3 km of the canyon of its tributary the Čikola River, with a total area of 142 km 2 was protected as a national park in 1985.In 1997, the boundaries were changed to exclude the area from the Šibenik Bridge to the Skradin Bridge from the protected zone, while the Krka Canyon from the Trošenj and Nečven fortresses to about 2 km downstream of the city of Knin was included, reducing the protected area to 109 km 2 (Ivić 2018) (Fig. 1).
oxycedrus.With the proclamation of the national park, a new impact of visitors began to appear with greater intensity, especially in the most visited places, Roški Slap and Skradinski Buk.
Although some floristic data on the Krka River area and its surrounding were published in the 19 th and 20 th centuries (Visiani 1826, 1842-1852, 1872, Hirc 1909, Gaži-Baskova 1983, Sekulić & Lovrić 1986, Garnweidner 1987, Lovrić & Bedalov 1987, Lovrić et al. 1987, Lovrić & Rac 1989, Trinajstić 1979, 1993), the first comprehensive floristic survey and flora mapping was conducted between 1989 and 1991 (Marković et al. 1990(Marković et al. , 1993)).Unfortunately, this project was not completed due to the hostilities that took place in 1991, which significantly affected the area of the national park.After the end of the war and during the border changes of 1997, the newly added, northern part of the park remained unexplored.Therefore, the Public Institution Krka National Park initiated the floristic mapping of that additional part of the park, which was carried out in the period from 2007 to 2009 (Hršak et al. 2009, Sedlar et al. 2010).Since the data for the old part of the park were already thirty years old at that time and referred to some areas that were no longer part of the park, there was a need to re-map the flora, and this was conducted from 2013 to 2019 (Hršak et al. 2020).At the same time there were several additional independent floristic studies (Milović 2007, 2016, Milović & Mitić 2009, Boršić et al. 2017, Pandža et al. 2017, Vuković et al. 2017 a, b).Although incomplete floristic data were cited, the Krka River area was recognized as an area of special botanical value and included in the Croatian list of Important Plant Areas (IPA) (Milović 2010).
The aim of this paper is to publish in one place an overview of all vascular plant taxa that were recorded in the Krka National Park during floristic studies conducted after the statutory protection of this area in 1985.

Material and methods
The taxa list is based on our own field studies performed in the new part of the park from 2007 to 2009 and in the old part of the park from 2013 to 2019.In both studies, detailed flora mapping was undertaken at a resolution of 1/64 of the basic MTB field, but these distribution data are not presented in this paper.The final list also includes taxa that were recorded in other, concurrent, studies, but were not found during our studies.Those taxa are marked in the list with numbers related to the following publications: 1 Marković et al. (1993), 2   Milović (2007), 3 Milović & Mitić (2009), 4 Milović (2016), 5 Bogdanović et al. (2016), 6 Vuković et al.

Results and discussion
A total of 1509 species and subspecies of vascular flora were recorded within the present boundaries of Krka National Park (Appendix 1).According to Flora Croatica Database (Nikolić 2005-onwards) they are classified into 582 genera and 132 families.
In the research carried out at the end of the 1980s in the old part of the park, which is still included in today's boundaries, 713 taxa were recorded (Marković et al. 1990(Marković et al. , 1993)).In our recent research into that old part of the park, 1101 taxa were recorded (Hršak et al. 2020), while the research into the new part of the park revealed 62 new taxa, previously not recorded in the park (Sedlar et al. 2010).
Among them, we should highlight the single population of Beckmannia eruciformis in Croatia at the confluence of the Čikola River and the Krka River.Furthermore, Damasonium polyspermum, an extremely rare species of Mediterranean temporary ponds in Croatia (Trinajstić et al. 1995, Boršić and Posavec Vukelić 2012, Vuković and Jelaska 2015) was recently found in the park during our research (Šegota et al. 2019).Another rather rare or overlooked species in the national context, Sternbergia colchiciflora, was recently found in the park too (Vuković et al. 2017).
As for endemics, there are 49 taxa which comprise 3.3% of the total flora.The population of Campanula fenestrellata ssp.fenestrelata from the Krka River was according to some previous opinions classified as the subendemic Campanula lepida Feer.(Lovrić & Rac 1989, Marković et al. 1993), however this was rejected by Rešetnik et al. (2020).The rare, data deficient endemic Succisella petteri was found in the inundation plain of the Krka River in the vicinity of Lake Visovac.Similar habitats were occupied by endemic Chouardia litardierei on several sites along the Krka water course.with long reflexed scales (Fig. 5).
A total of 149 non-indigenous plant taxa were registered in the park, amounting to 6.6% of the total flora.Among them, most are cultivated as ornamentals or as fruits and vegetables, while the others are weeds or casually introduced species.weldenii (E), rare Ophrys minuscula (F), endemic dwarf iris Iris adriatica in both colourations (G, H), rare macrophyte Damasonium polyspermum (I), rare Quercus trojana (J, K).

Conclusion
With its 1509 recorded taxa, the flora of the Krka National Park is extremely rich, considering that it is only about one hundred square kilometres in size.However, this apparent richness is largely due Appendix 1.The list of vascular flora of the Krka National Park.

Figure 1 .
Figure 1.The geographical position of the Krka National Park (red dot and area).
c u l a r f l o r a o f K r k a N a t i o n a l Pa r k ( C r o a t i a ) P R I L O Z I were used.The chorotypes were represented using following abbreviations: SE -south European, EUAS -Eurasian, CME -circum-Mediterranean, CUAD -cultivated and adventive, WSP -widespread plants, IM -Illyrian-Mediterranean endemic, EU -European, CHA -circum-Holarctic, EME -East Mediterranean, CEU -Central European, SEEU -Southeast European, MEAT -Mediterranean-Atlantic, MEPO -Mediterranean-Pontic, EEUPO -East European-Pontic, WME -West Mediterranean, EUME -Euro-Mediterranean and IBE -Illyrian-Balkan.The life-forms are according to Raunkiaer (1934): P -phanerophytes, Ch -chamaephytes, H -hemicryptophytes, G -geophytes, T -therophytes c u l a r f l o r a o f K r k a N a t i o n a l Pa r k ( C r o a t i a ) P R I L O Z I P O Z N A V A N J U F L O R E H R V A T S K E | C O N T R I B U T I O N S T O T H E K N O W L E D G E O F T H E C R O A T I A N F L O R A 1 0 ( 1 -2 ) | V E LJ A Č A 2 0 2 3 .

National
Park is remarkably rich for an area of only 109 km 2 .The great diversity of habitats certainly contributes to this floristic richness, as there are rocky pastures, vertical canyon cliffs, aquatic habitats, wet and dry grasslands, thermophilous and wet forests and thickets, reedbeds, as well as various anthropogenic habitats in the park.The high floristic richness is also supported by the specific phytogeographical position of the park, which is mostly located in the sub-Mediterranean zone, although the southern parts are on the border with the Eu-Mediterranean zone, so that true Mediterranean taxa penetrate the park as well.Krka National Park is floristically richer than any other Croatian protected area, partly due to the frequent and continuous floristic studies of the area.For example, there are 775 known taxa in the Mljet National Park (Hršak et al. 2012), 986 taxa in Plitvička jezera National Park (Krga, 1992), 809 taxa in the Paklenica National Park (Alegro 2004), 522 taxa in the Kopački Rit Nature Park (Rožac et al. 2019), 418 taxa in Lastovo Islands Nature Park (Škunca et al. 2008), and 400 taxa in the Vransko Lake Nature Park (Vuković et al. 2007b).The most numerous families in the flora of the NP Krka are Compositae (13%), followed by Poaceae and Fabaceae (9% each) (Fig. 2).The Lamiaceae are represented with 6%, Brassicaceae with 5%, Apiaceae with 4% and Rosaceae, Scrophulariaceae and Caryophyllaceae with 3% each (Fig. 2).The dominant chorotypes in the Krka NP are the south European chorotype (19%), Eurasian chorotype (18%) and circum-Mediterranean chorotype (15%) (Fig. 3).The high proportion of cultivated and adventive taxa (11%) is largely due to very rich garden flora of the island of Visovac, studied by Pandža (2017).The relatively high proportion of the widespread taxa (11%) reflects the significant number of plants from aquatic and wet habitats, as well as many weed and ruderal plants of anthropogenic habitats which are not rare in the park.The Illyrian-Mediterranean chorotype (6%) encompasses endemic taxa, which are a special value of the flora of the park.

Figure 2 .
Figure 2. The spectrum of plant families of the flora of the Krka NP.

Figure 3 .
Figure 3. Chorotype spectrum in the flora of the Krka NP (abbreviations explained in Material and methods).
graphical position.The main difference between Mediterranean and temperate zones is in the proportions of hemicryptophytes and therophytes: in the temperate zone hemicryptophytes prevail over therophytes, while the situation is inverse in the Mediterranean zone.The life-form spectrum of Krka NP has been compared to the life-form spectra of the neighbouring town of Šibenik and its surroundings (Milović 2002), the Mediterranean area generally (Horvat 1949) and temperate climatic zone (Wittig 2012) (Tab.1).In Krka NP the proportions of hemicryptophytes and therophytes are almost equal, representing an intermediate position between typically Mediterranean and temperate spectra.The flora clearly reflects the transitional position of Krka NP influenced by both the Mediterranean and the temperate climate.The higher proportion of hydrophytes than in Mediterranean areas is due to the high diversity of aquatic habitats (water courses, reservoirs, waterfalls, inundations) in the park.
c u l a r f l o r a o f K r k a N a t i o n a l Pa r k ( C r o a t i a ) P R I L O Z I P O Z N A V A N J U F L O R E H R V A T S K E | C O N T R I B U T I O N S T O T H E K N O W L E D G E O F T H E C R O A T I A N F L

Table 1
. Comparison of percentages of life-forms of Krka NP, the town of Šibenik and surroundings, Mediterranean areas generally and temperate climatic zone (H -hemicryptophytes, T -therophytes, G -geophytes, Ph -phanerophytes, Ch -chamaephytes and Hy -hydrophytes).Ecological analyses of the flora showed that the Ellenberg's ecological indicator values for light (EI-S) and air temperature (EI-T) are high (7/9 each), while indices for soil moisture (EI-V) are low (4/12).This implies the predominance of plants of the open, warmer and drier habitats in the area of the Krka NP.Ecological indicator values for moisture are low despite the significant number of hydrophytes in the park flora (4%