Vascular plant community composition from the campos rupestres of the Itacolomi State Park, Brazil

Abstract Campos rupestres are rare and endangered ecosystems that accommodate a species-rich flora with a high degree of endemism. Here, we make available a dataset from phytosociological surveys carried out in the Itacolomi State Park, Minas Gerais, southeastern Brazil. All species in a total of 30 plots of 10 x 10 m from two study sites were sampled. Their cardinality, a combination of cover and abundance, was estimated. Altogether, we registered occurrences from 161 different taxa from 114 genera and 47 families. The families with the most species were Poaceae and Asteraceae, followed by Cyperaceae. Abiotic descriptions, including soil properties such as type, acidity, nutrient or aluminum availability, cation exchange capacity, and saturation of bases, as well as the percentage of rocky outcrops and the mean inclination for each plot, are given. This dataset provides unique insights into the campo rupestre vegetation, its specific environment and the distribution of its diversity.


Introduction
Campos rupestres (literally: rock fields) are rare and endangered ecosystems composed of different physiognomies (Caiafa and Silva 2005) on quartzite material or sandstone, which displace forest formations in high altitudes (900 m above sea level) in southeastern Brazil (Magalhães 1966). These rock fields are considered species-rich, diverse ecosystems that contain many endemics (Giulietti and Pirani 1988, Pirani et al. 1994, Stannard 1995, Romero and Nakajima 1999, Conceição et al. 2007, Jacobi et al. 2007, Menini Neto et al. 2007, Messias et al. 2011. Nevertheless, the intensification of grazing, uncontrollable fires of anthropogenic origin, continued urbanization, dispersion of invasive plant species, collecting of endangered (medical) plants, mining activities and nutrient inputs from industry and traffic threaten the native flora and fauna (Pirani et al. 2003, Gastauer et al. 2012).
The Itacolomi State Park (ISP) is located in the Brazilian municipalities of Mariana and Ouro Preto, Minas Gerais state, south of the Espinhaço Mountain Range (Drummond 2005). Due to the characteristic mosaic of different physiognomies of campo rupestre vegetation and the seasonal semideciduous Atlantic forest (Peron 1989, Gastauer andMeira Neto 2013), the park contains a diverse flora with many endemics (Batista et al. 2004, Dutra et al. 2008, Dutra et al. 2009).
Although campos rupestres contain a high degree of endemic species, little data are available for this endangered ecosystem (Gastauer and Meira Neto 2013). The aim of this data paper is the distribution of a data set containing species lists from two campo rupestre communities from the ISP along with a list of soil parameters to increase knowledge of the actual distribution of campo rupestre species. rocks forming the peak, which are considered to be a mother and daughter by native people (Fig. 1).
The vegetation of the park is formed by a mosaic of seasonal semideciduous Atlantic forest and campos rupestres (Fujaco et al. 2010). In a recent census, which included this survey, 520 species had already been recorded for the ISP, but the magnitude of the total species richness of vascular plants is estimated to be between 880 and 1340 species (Gastauer and Meira Neto 2013). Habernaria itaculumia (Orchidaceae, Batista et al. 2004) and Chamaecrista dentata (Fabaceae, Dutra et al. 2008) are species endemic to the park.
Soils are of quartzitic origin, and rocky outcrops are distributed over both study sites. The climate of the park is of type Cwb, according to the Köppen classification (Peel et al. 2007). The climate is mesothermic, with mild, rainy summers and dry winters. The average temperature ranges between 17 and 18.5°C, and the annual precipitation reaches 1450 to 1800 mm (Werneck et al. 2000).
Two study sites were selected. The first study site, Lagoa Seca (Dry Pond in English), is situated near a periodically inundated area at the coordinates 20°25.96'S and 43°29.47'W, 1600 m above sea level in the center of the ISP (Fig. 2). The second study site, Calais, is situated near the boundary of the ISP at 20°24.61'S and 43°30.13'W, at an altitude of 1270 m. Both areas show a homogeneous, small-scale mosaic of gramineous vegetation, small shrubs and quartzite outcrops. Although the Lagoa Seca study site is well protected within the park, it burned in 2007 (Fundação Biodiversitas, personal communication), and the Calais area is impacted by invading cattle and fires that frequently become out of control in neighboring areas. Furthermore, settlement activities disturb the area with waste deposits from urban households and construction activities.

Sampling methods
Sampling description: At each study site, 15 plots of 10 x 10 m, arranged in 3 transects, were installed (Newton 2007). In each plot, the complete vegetation cover, its mean inclination and aspect, i.e., the compass direction that the slopes face, were estimated.
The cardinality, a combination of abundance and vegetation cover, of each species within each plot was estimated using the Wilmanns scale (Reichelt and Wilmanns 1973). This scale is easily converted to the more common, internationally accepted Braun-Blanquet system (Mueller-Dombois and Ellenberg 1974, Table 1).  Geographical position of the study sites within the ISP. Unknown species were collected and identified with the help of specialists, and a specimen from each was deposited in the OUPR herbarium from the Federal University of Ouro Preto (UFOP).
Soil samples were collected in each plot. From five equally distributed points in each plot, the upper 20 cm of the soil was removed using a hoe after the organic layers had been removed. The five samples of each plot were mixed, and then 500 g was weighed, stored in a plastic bag and transported to the lab. Immediately after arrival at the lab, the soil samples were air-dried.
The following parameters were analyzed in the laboratories of the Soil Department of the Federal University of Viçosa: soil texture (determination of the relative amounts of course and fine sand, silt and clay, separated by sieving); soil acidity (pH, extraction with water); the concentrations of phosphorus (P), potassium (K, both Mehlich 1 extraction), calcium (Ca), magnesium (Mg), and aluminum (Al, the previous three all extracted with 1 mol/L KCl); interchangeable bases (SB); the effective cation exchange capacity (CTC(t)), as well as the cation exchange capacity at pH 7 (CTC(T)); and the saturation of bases (V), aluminum (M) and remnant phosphorus (P-rem).

Taxonomic coverage
Description: In Lagoa Seca, we found 76 (morpho-)species from 55 genera and 25 families (Table 2), whereas we found 107 species from 82 genera and 33 families in Calais (Table 3). Due to the lack of appropriate material (e.g., flowers) to provide a definite determination, 15 morphospecies from Lagoa Seca and 13 from Calais were identified to only the genus level, 5 morphospecies from Lagoa Seca and 4 from Calais were identified to only the family level (Tables 2, 3). Altogether, 161 (morpho-) species belonging to 114 genera and 47 families were registered in this study. Most of them were angiosperms (156 species), but six fern and a lycophyte species were recorded as well.   Reichelt and Wilmanns (1973) (see Table 1 for details) surveyed on 12.10.2008 (plots 1-12) and 22.10.2008 (plots 13-15). The abbreviation ne is northeastern exposition, nw is northwestern exposition, s is southern exposition, se is southeastern exposition, sw is southwestern exposition and FO is frequency of occurrence, i.e., number of plots in which species occurred.  20 (morpho)species occur in both study sites, and these belong to the families Asteraceae (6 species), Poaceae (5), and Cyperaceae (3) The most dominant families in Lagoa Seca are Asteraceae (with 13 species), Poaceae (11), Cyperaceae (9), Melastomataceae (7) and Orchidaceae (6). Asteraceae and Poaceae, each with 19 species, are the most species-rich families found in the Calais study site, followed by Fabaceae (13), Cyperaceae (9) and Melastomataceae (6). The family Fabaceae, well-represented in Calais, is completely lacking in Lagoa Seca. On the other hand, the family Orchidaceae shows a higher richness in the Lagoa Seca area.
The number of species per plot varies between 16 and 33 in Lagoa Seca and between 21 and 43 in Calais. The number of uniques, i.e., species that occur within one plot only, is high for both study sites. Three species, Paspalum caryophaeum, Schizachyrium sanguine um and Rhynchosphora sp. 1, occur in all 15 plots of Lagoa Seca, but the most dominant species from Calais is Melinis minutiflora, occurring in 13 out of 15 plots.

Temporal coverage
Notes: Two field campaigns were undertaken to collect soil samples and to survey community composition. The first one took place between the 20 and 22 of October 2008; the second one was carried out between the 9 and 10 of January 2009. Species not identified during the field work were collected and identified within two or three days after return from the field. Soil samples from both study sites were analyzed in February 2009.

Description of the Darwin Core Archive containing dataset
Column labels and descriptions of further Darwin Core Archive files from both datasets are given at  Table 8.
Column labels and descriptions of distribution.txt from Darwin Core Archives dwcacamporupestre-15plot-survey-sampling-itacolomi-lagoa076-checklist.zip (Suppl. material 1) and dwca-camporupestre-15plot-survey-sampling-itacolomi-calais107-checklist.zip (Suppl. material 2) containing the taxa occurrences within 15 plots of 10 x 10 in both study sites eventDate Date-time at which the taxon was registered at the location source Related resource from which the described resource is derived, here the DOI of bibliography citing this dataset occurrenceRemarks Further comments or notes about the occurrence of the taxon at the location   Table 9.