1. Introduction

Native subtropical grasslands at South Brazil plateaus are located at high altitudes where low temperatures and high annual rainfall usually predominate. Riparian areas in Campos Gerais are combined by moderate to poorly drained soils, covered by hydrophilous steppes or by pioneering formations of fluvial influence, where Haplic Histosols, Melanic Gleysols, or Fluvic Leptosols can be encountered. In addition, hygrophilous to mesic steppes typically encompassing herbs and shrubs species, where Litholic Leptosols and Haplic Inceptisols are also available[1],[2].

The great ecological relevance of the Brazilian Atlantic Rainforest biome, which includes grasslands, has given this area the status as global biodiversity hotspots[3],[4]. The remaining grasslands in the state of Paraná have been suffering severe anthropogenic pressure, especially due to the expansion of agriculture and non-native forestry activities. However, despite the global importance of this grassland ecosystem, their floristic richness is hardly known. Therefore as one of the first steps of the Biodiversity of grassland-forest ecotones in South Brazil Project team was to provide a species checklist of Pitangui river valley native grasslands. Their adaptive lifeforms were previously discussed by Mioduski & Moro[5].

2. Methods

We carried out this floristic study in the dip slope of 1^st cuesta of state of Paraná (Devonian Slope), inserted over Furnas sandstone, with medium altitude of 980 m a.s.l. The area is comprised of the region nationally known as Campos Gerais, specially where Pitangui river flows within a canyon in its medium curse crossing the Slope (J 594408 E 7232272), after Alagados dam, between Ponta Grossa and Carambeí municipalities, Paraná State (Figure 1). The climate is Cfb (altitudinal subtropical humid) according to Köppen’s classification, with mean annual temperature between 18 and 19C, and an average rainfall of 1,600mm/yr[6].

Sample collection was carried out monthly over a two year period (August 2009/July 2011) in an 9.4 ha area inserted over Furnas sandstone formation on superficial soils of 1 meter or less. According to the Brazilian Soil classification system, the Abrigo Pitangui site (A) is an 2.1 ha concave slope whith Haplic Cambissols, Litolic Neossols and Fluvic Neossols in sequence. The Usina São Jorge site (B) is an 0.2 ha flat surface with Haplic Cambissols, The Fazenda Panorama site (C) is an 4.0 ha slightly convex slope with Haplic Cambissols, and the Mirante Pitangui site (D) is an 3.1 ha slightly convex slope with Litolic Neossols.

Figure 1. Location of the sampled areas in Pitangui river valley, Southern Brazil: A- Abrigo Pitangui; B – Usina São Jorge; C – Fazenda Panorama; D – Mirante Pitangui

Botanical material was collected according to the wandering method described in Filgueiras et al.[7], that consists of listing the species presented in each delimited area as the investigator walks slowly on straight lines along it. Vouchers are deposited in the UEPG herbarium (HUPG), and research has been authorized by SISBIO 28694/1. For species’ taxonomic classification, Tryon and Tryon[8] and Smith et al.[9] for Ferns, and Angiosperm Phylogeny Group III[10] for Angiosperms were followed. The official plant names and their authors followed the electronic databases of Kew Gardens Plant List[11].

Evaluation and enumeration of the presence of extinction threatened species in the study area through comparison and review of Brazilian official threatened species lists [12],[13],[14] was also conducted. In addition, the presence of non-native plant (exotic) species was evaluated through revisions of the local governmental list[15] and Horus Institute[16].

3. Results and Discussion

Among the four areas, we recorded 421 taxa distributed in 51 Angiosperm families, one Conifer and 4 Ferns. There were present 420 species and 196 genera (Table 1). One Aristida taxon (Poaceae) was identified only at the generic level at this moment, needing further studies to settle it as a new species.

Table 1. Grassland plants present at Pitangui river valley, Southern Brazil. Habit: He – herbaceous; Sh – forbs; Tr - treelets; Li – prostrated herbs; Hc - Humic Cambissols; Ha - Haplic Cambissols; Ln - Litolic Neossols; Fc - Fluvic Cambissols

Families with the highest taxa number were Asteraceae (119) followed by Fabaceae (41), Poaceae (38) and Cyperaceae (28), summing up 54% of the total species richness, i.e., the number of taxa in the area.

Previously, in Campos Gerais region, including both mesic and hygrophilous species, in the Vila Velha State Park grassland, Cervi et al.[17] have found around 47% of the species richness consisted of 182 taxa of the Asteraceae family, 130 Poaceae, 89 Fabaceae, and 47 Cyperaceae. In the same environment, in the Guartelá State Park, Carmo[18] has found 28% of the species richness composed of 79 Asteraceae, 42 Fabaceae, 35 Poaceae, and 22 Cyperaceae. Outside the conservation zone, those surveys restricted to hygrophilous species, in the Tibagi river valley, only 27 species from Asteraceae family were found, together with 24 species of Poaceae, and 18 Cyperaceae[19]. All these contributed 47% of the total species richness in the surveyed area. Kozera et al.[20], in the Iguaçu river floodplain, have identified lesser, consisting of 15 species from Asteraceae family, 45 Poaceae 28, Cyperaceae and one Fabaceae, comprising 50% of the total species richness. The Asteraceae and Fabaceae species diversity increases the biological diversity due to the higher elevation of river banks, allowing the existence of non-hydromorphic soils.

Generally, the grassland of Pitangui river valley areas were dominated by herb species consisting of 79.8% of the total plant types. Shrubs which comprised the 15.4% consisted of the families, Asteraceae, Fabaceae, Malpighiaceae, Ericaceae, and Myrtaceae. In addition, treelets (1.0%) were observed consisted of the species Myrcia multiflora (Lam.) DC. and Plenckia populnea Reissek, both configuring rare plant forms in grasslands. The occurrence of these species is probably related to remnants of savannahs present in the vicinity of the study area. Prostrated herbs combine 3.8% of the phytocoenosis.

Twelve species are quoted on the list of threatened species of the state of Paraná[12] as rare: Ruellia multifolia (Nees) Lindau (Acanthaceae), Gomphrena macrocephala A.St.-Hil. (Amaranthaceae), Pfaffia jubata Mart. (Amaranthaceae), Mandevilla coccinea (Hook. & Arn.) Woodson(Apocynaceae), Butia microspadix Burret (as B. hatschbachii Glasmann) (Arecaceae), Halimium brasiliense (Lam.) Gross. (Cistaceae), Cayaponia espelina (Silva Manso) Cogn. (Cucurbitaceae), and Campomanesia pubescens (Mart. ex DC.) O.Berg (Myrtaceae); as endangered: Chrysolaena nicolackii H.Rob. (Asteraceae), Cuphea hatschbachii Lourteig (Lythraceae), and Dorstenia cayapia Vell. (Moraceae); as vulnerable: Caryocar brasiliense A.St.-Hil. (Caryocaraceae). In addition, there were six non-native grass species: Brachiaria decumbens Stapf.[15], Melinis minutiflora P.Beauv., Melinis repens (Willd.) Ziska, and Pennisetum purpureum Schumach.[16], all belonging to African genera of the Poaceae family. The high levels of biological contamination with the pines Pinus taeda L. and Pinus elliottii Engelm. (Pinaceae) and its implications for the Campos Gerais grassland conservation have already been discussed by Ziller & Galvão[21]. They have found 76% of grassland with pine contamination and even pointing their high potential for environmental degradation, public policies could not be effective yet for its control.

4. Conclusions

The species richness of Pitangui river valley grassland was higher (420 species on 8.3 ha) compared to available data from Campos Gerais region, as listed from the Vila Velha and Guartelá State Parks which were made upon larger protected areas. Asteraceae, Fabaceae, Poaceae, and Cyperaceae are the main families in this ecosystem. The presence of non-native species (4 species), and invasive Pinus species (2 species), and the increasing number of threatened species is alarming considering the location and the size of the area. Therefore, it is only high time to suggest that additional zoning and better management effort be the concern of the authorities to conserve the Campos Gerais National Park and its vicinities

ACKNOWLEDGEMENTS

We are grateful to the owner of the area, Companhia de Energia Elétrica do Paraná (COPEL), as to the MCT/CNPq/MEC/CAPES/FNDCT nº 47/2010 – SISBIOTA BRASIL for their financial supporting.