Vascular grassland plants of Tibagi River Spring , Ponta Grossa , Brazil

A systematic survey was carried out on wet grasslands found over Histosols at Upper Tibagi River basin, between Ponta Grossa and Palmeira municipalities, in the state of Parana, Brazil, place of high importance because of soil water retention capability and soil carbon pool composition. We provide a checklist containing 146 species, 96 genera and 42 plant families for the area. Families with higher species richness were Asteraceae (27 species; 21 genera), Poaceae (24; 16) and Cyperaceae (18; 6). Four species were classified as endangered or rare, and one as exotic. The specific richness in wet grassland environments at the state of Parana underlines the need for conservation efforts encompassing these formations.


Introduction
The most important Rivers of the state of Paraná -Brazil, have their springs located at high altitudes (540 to 1,680 m a.s.l., MINEROPAR 2006), where low temperatures (-7.8 to 2°C, Maack 1981) and high annual rainfall (1,300 to 3,470 mm/year, Maack 1981) usually predominate, like Serra do Mar, Escarpa Devoniana or 1 st cuesta (geomorphological shape between 1 st and 2 nd Paraná plateau) and Serra Geral or 2 nd cuesta (geomorphological shape between 2 nd and 3 rd Paraná plateau).
Among these Rivers, the Tibagi presents various springs inserted in the dip slopes of the 1 st cuesta (higher altitude), many of them under diffuse water flux in Histosols.
The Organossolos (Santos et al. 2006), resembling Histosols by Soil Survey Staff (2006), are soils located in reliefs that promote water saturation (Birkeland 1999), usually acid, with high cation exchange capacity (CEC), low nutrient availability (Breemen 1995) and low base saturation, with eventual average to high base saturation (Santos et al. 2006;Valladares et al. 2008) and large amounts of exchangeable aluminum.Pedogenesis in these soils are related to a water table level near the soil surface, with no important changes along the year, under anoxic conditions, which reduces the organic matter mineralization, thus promoting the storage of carbon-rich organic matter complexes (Santos et al. 2006;Sá 2007) and favouring pedogenetic processes.
Herb species predominate along areas covered by hydric soils, into high relief plateaus (wet grasslands) (Gates 1915;Breemen 1995;Costa et al. 2003).Besides the studies found in Costa et al. (2003), Cervi et al. (2007) and Kozera et al. (2009), little information is available regarding areas with similar abiotic conditions.Floristic studies of wet grasslands do not encompass only organic soils, but also mineral hydric soils.Costa et al. (2003) and Cervi et al. (2007)  Abstract: A systematic survey was carried out on wet grasslands found over Histosols at Upper Tibagi River basin, between Ponta Grossa and Palmeira municipalities, in the state of Paraná, Brazil, place of high importance because of soil water retention capability and soil carbon pool composition.We provide a checklist containing 146 species, 96 genera and 42 plant families for the area.Families with higher species richness were Asteraceae (27 species; 21 genera), Poaceae (24; 16) and Cyperaceae (18; 6).Four species were classified as endangered or rare, and one as exotic.The specific richness in wet grassland environments at the state of Paraná underlines the need for conservation efforts encompassing these formations.
concave relief), where Histosols or Organossolos Háplicos predominate due to genetic processes such as accumulation of organic material, especially herb species and bryophytes.In order to analyze floristic composition, we sampled 0.65 ha (115 x 57 m) from September 2008 to November 2009, in fortnightly field expeditions.The site is constantly grazed by sheep and cattle, a common situation in most natural grasslands in southern Brazil.
In each field expedition we collected botanical material according to the method described in Filgueiras et al. (1994).Surveys encompassed the same soil order, in areas with hydric conditions ranging from a water table located near the surface (a usual condition within this soil order) to a water table rather distant from the surface, a condition promoted by gully erosion that have altered local hydrological regimes.The gully erosion is present in one among the several geological faults in the area as observed in Figure 1.
We collected and preserved plant material from all vascular plant species found within the study area, preferably with reproductive structures.Vouchers for each species were deposited at MBM Herbarium, and a duplicate of each was sent to UPCB Herbarium.
Towards a better understanding of this environment, we carried out a preliminary survey of moss species present in the study area.Since a thorough survey encompassing mosses would probably result in higher species richness, we excluded the species we found from the presented checklist, although they are mentioned in our results.
For species taxonomic classification, we followed Tryon and Tryon (1982) and Smith et al. (2006) for Pterydophyta and Angiosperm Phylogeny Group III (APG III 2009) for angiosperms.We researched valid plant names in electronic databases of World checklists (Kew 2008; especially for monocots), Missouri Botanical Garden website (MOBOT 2008) and The International Plant Names Index website (IPNI 2008).Citation of author names follows Brummit and Powell (1992) and Pichi-Sermolli (1996).
We evaluated the presence of extinction-threatened species in the study area through revision of extinctionthreatened species lists (Hatschbach and Ziller 1995;IBAMA 1992 andMMA 2008).The presence of exotic plant species was evaluated through revision of a local governmental list (IAP 2009).
The floristic similarity between these data, Kozera (2008) and Costa et al. (2003), were calculated using Sorensen index.This analysis was carried out using software MULTIV beta (Pillar 2006).

Results and Discussion
We recorded 146 grassland taxa (132 angiosperms and 14 ferns) distributed in 42 families (Table 1).One taxon was identified only at the family level, five at the generic level.In order to achieve a better understanding of environment conditions at the study area, four moss species, were accounted for a preliminary survey: Sphagnum oxyphyllum Warnst.and Sphagnum recurvum P. Beauv (Sphagnaceae), Pogonatum pensylvannicum (Hedw.)P. Beauv.and Polytrichum commune L. (Polytrichaceae).
Families with the highest species number were Asteraceae, Poaceae and Cyperaceae.The same result was verified in other floristic and phytosociological surveys in Southern Brazil, both in hydric (Kozera et al. 2009;Setubal and Boldrini 2010) and non-hydric soils (Buselato and Bueno 1981;Boldrini and Miotto 1987;Zocche and Porto 1992).
Poaceae plays a key role defining landscapes along the study area, due to the abundance of cespitous species such as Andropogon leucostachyus, Paspalum flaccidum and Leptocoryphium lanatum.Cyperaceae is recognized as a characteristic family of wet tropical environments (Goetghebeur 1998;Alves et al. 2008), and was significantly represented by Cyperus and Rhynchospora.Asteraceae showed an important physiognomic value, especially due to the shrub Baccharis crispa.
No Fabaceae species were found, probably due to the waterlogged condition.Similarly, Kozera et al. 2009 andCosta et al. 2003 found only one Fabaceae species in their surveys, both carried out in similar waterlogged conditions.On the other hand, in surveys carried out under well-drained mineral soils, Fabaceae was among the richest families (Boldrini and Miotto 1987;Boldrini and Eggers 1996;Boldrini et al. 1998;Setubal and Boldrini 2010).
We observed dominance of tropical species, but there were also many temperate species like Briza calotheca, Danthonia montana and Piptochaetium montevidense.Herb species predominated along this evaluation, and most shrubs belong to Asteraceae, Clusiaceae, Ericaceae, Melastomataceae, Scrophulariaceae and Solanaceae.Also, we observed tree species (Myrsine cf.gardneriana and Rhamnus sphaerosperma Sw.), both configuring uncommon plant species in wet grasslands, according to Tannus and Assis ( 2004), since the organic matter accumulation under anoxic conditions is a limiting condition for the establishment of trees.The occurrence of these species is probably related to the presence of gully erosion, which altered soil features, and can be interpreted as an indicative of poor environmental quality.Four species are present in the list of threatened species of the state of Paraná (Hatschbach and Ziller 1995) and also in the Brazilian Federal list of threatened species (MMA 2008): Baccharis megapotamica Spreng.(Asteraceae), Cyanaeorchis arundinae (Rchb.f.) Barb.Rodr.(Orchidaceae), Paepalanthus catharinae Ruhland (Eriocaulaceae) and Dicksonia sellowiana Hook.(Dicksoniaceae).The first two were classified as rare and the last two as endangered.The first three species highlight the urgent need for conservation efforts encompassing similar areas, associated to programs that promote good management of nearby protected areas.The presence of Dicksonia sellowiana, an uncommon species in wet grasslands, was probably a result of soil water balance alterations promoted by gully erosion.The presence of the exotic species Deparia petersenii (Kunze) M. Kato (Dryopteridaceae), would suggest a potential impact on grassland habitats.
Floristic similarity between the present study and Kozera et al. (2009) and Costa et al. (2003) was respectively 32.3% and 5.2 %, whereas similarity between these two studies was 10.8%.The higher similarity observed between this study and Kozera et al. (2009) is probably due to the geographic location (second plateau of State of Paraná).The number of sampled species is probably another factor that leads to the differences observed among the studies: Kozera et al. (2009) found 175 species (Cyperus virens Michx.and C. intricatus Schrad ex.Schult were considered synonyms), whereas Costa et al. (2003) found 47 species (Sphagnum sp. was not considered in the analysis).The study area of Costa et al. (2003) and Kozera et al. (2009) covered also hydric soils, but probably under organic and inorganic soil.Therefore, these authors sampled soils with different chemical and physical soil features, which probably influenced the vegetation composition.
Over the last years, grasslands in state of Paraná had their original extension reduced with the substitution of natural vegetation by crops.Even in a small sampling area, we recorded an species-rich vegetation, so we consider these vegetation data useful for supporting the elaboration of public conservation policies concerning the remaining natural areas and, moreover, efforts aiming the restoration of disturbed places.
studied the floristic composition of floodplains with different chemical and physical soil features, which affect vegetation.Kozera et al. (2009) Check List | Volume 7 | Issue 3 | 2011

Figure 1 .
Figure 1.Map location of Tibagi River Spring (black dot) in the state of Paraná and in Brazil, and Landsat 5TM image of study area.