Floristic survey of the Furnas Gêmeas region , Campos Gerais National Park , Paraná state , southern Brazil

To investigate the resilience of the grassland flora of the Campos Gerais phytogeographic zone, this study surveys the phanerogamic plant species occurring in the Furnas Gêmeas area (Campos Gerais National Park, Paraná state, southern Brazil), especially those resilient to fragmentation by crops and fire. Collections were made monthly from October 2002 to May 2004 and occasionally from 2005 to 2013. In total, 313 species belonging to 70 angiosperms families and 2 gymnosperm families were collected. Just 4 angiosperm taxa were not determined to species. Although the Furnas Gêmeas has suffered from very evident anthropogenic changes, the vegetation retains part of its original richness, as seen in better-preserved areas outside the park. Included in our list are endangered species that need urgent measures for their conservation.


Introduction
In Paraná state, Brazil, in the phytogeographic zone known as Campos Gerais (Maack 1948), there are several natural round depressions formed by sandstone collapse, the furnas, which specifically occur in outcrop areas of the Furnas Formation in the intracratonic Paraná Basin (Soares 1989).These depressions generally have water or dense vegetation inside (Soares 1989) and above them occurs natural grassland vegetation in a mosaic with Araucaria temperate forest patches.Among the 14 known furnas in the Campos Gerais region (Soares 1989), 3 are within Campos Gerais National Park (CGNP).
The Campos Gerais native vegetation is threatened by its intense replacement to crops or pine plantations (Ziller 2000, Melo et al. 2007), which prevent native grasses from surviving and can lead to degradation of fragile soils (Pillar 2006, Dalazoana 2010).Thus, the Brazilian government has considered the region conservation as priority (MMA 2007).
Studies in the Campos Gerais phytogeographic zone have shown a high species richness that includes rare and endangered species (Cervi et al. 2007, Nanuncio and Moro 2008, Dalazoana 2010, Ritter et al. 2010, Andrade et al. 2011, Mioduski and Moro 2011, Carmo et al. 2012, Carmo and Assis 2012, Moro et al. 2012).However, all of these studies were undertaken in relatively well-preserved landscapes.In impacted areas, the flora is little known, and thus, an assessment of species resilience to anthropogenic changes is required.
We choose an area in the CGNP that has undergone anthropogenic changes, including annual cropping, burning, and development for recreation (hiking routes).Even so, the Furnas Gêmeas site still preserves much of its native vegetation.We investigated the presence of resilient species by comparing the Furnas Gêmeas floristic list to those of four more intact areas outside of the CGNP, which we considered reference areas.

Methods
Study site.With an area of 21,500 ha, CGNP is located in the municipalities of Ponta Grossa, Castro, and Carambeí, Paraná, southern Brazil.This national park was created in March 2006 with the aim to preserve some of the last remnants of natural grasslands and their rich flora and fauna.These grasslands were traditionally exploited for livestock, but in recent decades, they are being replaced by crops and pine plantations (Brasil 2008).
Furna 1 (80 m wide × 50 m deep) and Furna 2 (17 m wide × 53 m deep) are separated by a small 60-100 m strip of land (Soares 1989).Trees that are typical of Araucaria forest occur inside of these furnas; outside of them, grassland vegetation prevails among the outcrops of sandstone (Fig. 2).
The climate of CGNP is Cfb (Altitudinal Subtropical Humid) according to the Koeppen classification, with a  According Embrapa (2008), the shallow young soils are mainly lithosols (Neossolos litólicos), regosols (Neossolos Regolíticos), and haplic cambisols (Cambissolos háplicos), with frequent rocky outcrops that are very susceptible to erosion (Melo et al. 2007).Until the 1970s, the main economic activity in the region was cattle ranching on native grasslands, but crops under notillage system have replaced ranching.More recently, monocultures of pine have been planted on most nonfarmable land (Ziller 2000).
Data collection.In order to record plants in a spatial scale we used a 50 × 50 m grid, placed over an aerial image of the study area, using ArcGIS 10.3 and the basemap of the ArcGIS Online (Fig. 3).We visited the study area monthly from October 2002 to May 2004 (totaling 20 months), and sporadically from 2005 to 2013, collecting phanerogamic plant specimens in their reproductive state.
We follow the standard procedures for preparing botanic material (Fidalgo and Bononi 1984) and deposited vouchers in the HUPG herbarium.Identifications were made by consulting the literature and collections of the HUPG, MBM and UPCB herbaria (acronyms according to Thiers 2016).
The taxonomic classification of angiosperms follows APG IV (2016), and of gymnosperms, Bowe et al.We checked the presence of threatened species according to the Lista Oficial das Espécies da Flora Brasileira Ameaçadas de Extinção (MMA 2014) and the Lista vermelha de plantas ameaçadas de extinção no estado do Paraná (Paraná 1995).
A comparative analysis between FG and the reference areas shows considerable similarity between them, except for Vila Velha State Park.The Furnas Gêmeas and Piraí da Serra areas show of the greatest similarity (Fig. 4).

Discussion
The vegetation of Furnas Gêmeas presents low species richness when compared to better-preserved areas in the Campos Gerais region (Carmo 2006, Cervi et al. 2007, Nanuncio and Moro 2008, Moro et al. 2012).Furthermore, invasive exotic species are common.This high level of biological contamination has severe implications for biodiversity and conservation of southern Brazilian grasslands (Ziller and Galvão 2002).
We found the high richness of Asteraceae, Poaceae, Myrtaceae, Fabaceae, Rubiaceae, Melastomataceae, and Cyperaceae.Several studies have pointed these families as having the larger number of taxa in the Campos Gerais region (Hatschbach and Moreira Filho 1972, Carmo 2006, Cervi et al. 2007, Nanuncio and Moro 2008, Dalazoana and Moro 2011, Moro et al. 2012, Silva et al. 2016), and therefore, we noticed that FG still retains part of its original flora.
Most of the weeds are native.Possibly favored by both wind dispersal and by frequent anthropogenic fires, they contribute to a highly resilient herbaceous community (Gómez-González et al. 2011).However, exotic species could out-compete the native species (Ziller 2000).
It is clear that in the Campos Gerais a remarkably varied habitat having high species richness.Although our survey studied just a small part of this fragmented landscape and our data are not exhaustive, these results are show the need for additional studies.Continued impacts may lead to increased biological contamination, eliminating native species and further degrading habitats.Priority must be given to the management of grassland areas to minimize anthropogenic pressures and to promote natural regeneration that will help conserve plant and animal species.FG harbors rare and threatened species that demand urgent conservation measures.We recommend that access to FG be closed as a way to prevent the advancement of invasive species.

Figure 1 .
Figure 1.Location of the study site in Furnas Gêmeas, Campos Gerais National Park, Paraná state, Brazil.

Figure 3 .
Figure 3.The 50 × 50 m grid to locate the species sampled in Furnas Gêmeas, Campos Gerais National Park, Paraná state, Brazil.