Forest Structure and the Species Composition of the Parque Estadual Mata Atlântica , Located in Goiás State , Brazil

The Parque Estadual Mata Atlântica (PEMA), Goiás state, Brazil, is an Atlantic Forest reserve which has not been studied yet. The aims were to investigate plant biodiversity and characterize the flora to support the management plan.We adopt the point-centered quarter method to inventory the tree-shrub and lianas with the diameter at breast height more than or equal to 5 cm.The study was performed through 1.86 km of transect with 187 sampled points. We sampled 748 individuals and identified 109 species, 82 genera, and 51 families. The Shannon-Wiener diversity index (H󸀠) was 3.97, and Pielou’s evenness (J) was 0.846, both considered high.The Fabaceae family was the most diverse with 20 species. Aspidosperma polyneuron, an endangered tree species, had greater relative dominance and importance value.The floristic similarity analysis indicated that the PEMAvegetation belongs to the seasonal forest, currently very fragmented and degraded. Due to several anthropogenic threats, we suggest the following recommendations: prevent the exploitation of species, avoid hunting, control invasive grasses, prevent forest fires, and promote environmental education.This study demonstrates the importance of PEMA for species conservation. Therefore, this study is essential for the development of management plan and the conservation of PEMA biodiversity.


Introduction
The Atlantic Forest Domain (AFD) is the second largest American rainforest [1], recognized as a global biodiversity hotspot [2].This forest originally covered ca.148 million hectares; approximately 92% is distributed in 17 Brazilian states, and the remainder belongs to Argentina and Paraguay [3,4].
The classification of Brazilian vegetation recognizes two groups in the Atlantic Forest Domain: rainforests and seasonal forests [5].The rainforests occur near the coast.The Seasonal Dry Neotropical Forests (SDNF) are inland in the country as enclaves in the Cerrado and Caatinga biomes [5,6].These forests occur in disjunct patches scattered throughout the Neotropic, and the major biomes where SDNF is in contact are the savanna woodland (e.g., the Cerrado), lowland tropical rainforest, and montane forest [7].An estimate indicates that the extent of SDNF makes up about 15% of the Cerrado area (ca.300,000 km 2 ) in small areas or up to tens of thousands of square kilometers, for example, "Mato Grosso Goiano" in central region of Goiás state and "Triângulo Mineiro" in Minas Gerais state [8].Other disjunctions of SDNF in the valleys of São Francisco and Paraná rivers in Goiás and Tocantins states are not measured [9].
Despite the importance of the Atlantic Forest, it is very fragmented and degraded, and therefore the remnants are important for conservation [10].Thus, the conservation of AFD becomes a challenge due to various factors (fires, deforestations, and fragmentation), especially because of the high level of human disturbance [11].It is necessary to 2 International Journal of Ecology conduct floristic studies and to create new reserves, especially in higher diversity areas [12][13][14][15].
The aims of the present study were to inventory the flora of tree-shrubs and lianas of Parque Estadual Mata Atlântica (PEMA), located in the Água Limpa municipality, Goiás state, Brazil, to improve the knowledge of local flora, and to support the management plan of PEMA.1).

Materials and Methods
The average elevation of PEMA is 611 m, bordered by Brisas Reservoir that belongs to the Itumbiara hydroelectric dam, Goiás, Brazil (Figure 1).The soils are Dystrophic Litholic Neosols-Eutrophic Haplic Cambisols to red Eutrophic Argisols [16].The climate is characterized by two distinct seasons, a hot and rainy season from November to March and a dry season from April to October [17].The climate is classified as Aw (Köppen) (tropical with summer rains).The average annual temperature is 23.5 ∘ C, and average annual rainfall is 1.314 mm for Água Limpa city, Goiás [17].

Vegetation Inventory and Data
Analysis.We used the point-centered quarter method (PCQM) for phytosociological survey.The distance between sampling points was 10 m, totaling 187 sampling points in 1.86 km of nine transects.We registered the distance from the point, height, and diameter from all trees, shrubs, and lianas, live or dead, whose diameter at breast height (DBH) was equal to or larger than 5 cm.We analyzed the following phytosociological parameters: Shannon-Wiener diversity index (  ), Pielou's evenness () [18], relative density (RD), relative dominance (RDo), relative frequency (RF), and importance value (IV) [19].
The species accumulation curve was constructed to evaluate sampling sufficiency.The estimation of species richness was performed using the Jackknife 1 estimator [20] in the EstimateS program version 9.1 [21].These results were used for construction of observed (Mao Tao) and estimated species accumulation curves.
The presence/absence matrix for all species founded in PEMA was compared with other domains: Atlantic Forest Domain (AFD), including Seasonal Dry Neotropical Forests (SDNF), Cerrado, and Amazonian Rainforest (ARF).The categorization of the main phytophysiognomy in which the species occurs was based on the literature records [8,[22][23][24].This data matrix was used to perform a cluster analysis using the Jaccard Similarity Index as a measure of similarity between PEMA and the other biomes by Unweighted Pair Group Method with Arithmetic Mean (UPGMA).Statistical analyses were done in R program (R Core Team, 2017) (https://www.R-project.org/),using the "vegan" package (Oksanen et al., 2017) (https://CRAN.R-project.org/package=vegan) (last access in 04/09/2017).
The individuals were identified in situ or by botanical samples in laboratory analysis.The fertile botanical material will be deposited in the Universidade Estadual de Goiás (UEG) herbarium.Species nomenclature was standardized according to the Plant List (http://www.theplantlist.org/), the International Plant Name Index (http://www.ipni.org),and Jardim Botânico do Rio de Janeiro (http://floradobrasil.jbrj.gov.br/reflora/floradobrasil/FB90947).The APG IV was used for the botanic classification of species, genera, and families [25].

Results
The study was performed through 1.86 km of transect with 187 sampled points.We sampled 748 individuals and identified 109 species, 82 genera, and 51 families.The Shannon-Wiener diversity index (  ) was 3.97, and Pielou's evenness () was 0.846.The estimated richness was higher than the observed richness (Figure 2).
Cluster analysis of floristic similarities showed that about 80% of the PEMA species were shared with the SDNF.The PEMA species compared to other biomes showed two welldefined groups (PEMA-Dry Neotropical Seasonal Forest and AFD), indicating >75% of species similarity from PEMA with AFD (Figure 4).Additionally, 68% of the PEMA species also occur in Cerrado (Figure 4).The group including only the Amazon Rainforest suggests that only about 27% of the PEMA species also occur in the Amazon (Figure 4).

Discussion
Previous phytosociological studies in the Seasonal Dry Neotropical Forests indicated index rarely exceeding 3.5 [26].However, the Shannon-Wiener diversity index obtained in this study (  = 3.97), as well the evenness ( = 0.846), was higher.These values are equivalent to other studies in well-preserved semideciduous seasonal forest remnants [26].For example, Pereira et al. [27] obtained a diversity index of   = 3.58 in a seasonal forest located in the same river basin of the PEMA.Thus, PEMA has a great biodiversity in the shrub-tree strata [28].Moreover, the diversity estimator proposed by Heltshe and Forrester [20] indicated that the estimated richness was higher than observed richness (Figure 2).Besides, the sample sufficiency measured by the species accumulation curve indicates that it has not reached an asymptote (see Figure 2).Schilling and Ferreira [29] reported that community boundaries in tropical forests are difficult to define, especially due to high species richness, so the curve does not stabilize even with large samples.
The Fabaceae family presented the greater diversity, since it is a characteristic family from seasonal forests, which is well represented in most studies in Atlantic Forest Domain [29,30].In PEMA, the common pattern for forests was observed, where few species are abundant and many species are rare [30].For example, the 10 species with the highest relative density contributed approximately 40.43% of the living individuals.Another 39 species contributed to only one individual.However, many of these species can be considered numerically rare only for a given area at a given time but not necessarily from a biological viewpoint [31].For example, the dominant species Aspidosperma polyneuron is common in semideciduous seasonal forests (SSF) [32,33] but is listed as endangered species because of its high economic value and declining population [34,35].
A total of 54 dead individuals represented about 7% of the sampled plants and the highest IV (18.87) and RF (7.85) and second largest RD.All these values are considered relatively high when compared to those found in riparian forest (IV = 9.92; RD = 3.88) [27].The high rate of dead individuals resulted from disturbances like fires, since their thin bark does not tolerate high temperatures; therefore, tree mortality influences the forest dynamics [36].For the lianas, the relative density (RD = 4.15%) and importance value (IV 8.95) were relatively low, totaling only 31 individuals.However, the lianas can be represented by high percentages (15-25%) of the individuals in tropical forests [37].In the Amazon, the lianas percentages may reach up to 44% of the forest species, caused mainly by changes in environmental gradients [38].Thus, like the dead individuals, the lianas influence the dynamics, structure, and the diversity of tropical forests [39].The increase in density of lianas, mainly due to forest disturbances, becomes an impact indicator [38,40].Although the high densities of lianas can be considered a negative factor to forest [41,42], lianas are important component of forest ecosystems, originally recognized by Darwin.

International Journal of Ecology
The results of cluster analysis showed that about 80% of the PEMA species were common to the SDNF, and a similarity >75% of the PEMA species also occurred in AFD (Figure 4).PEMA is a transitional area between Cerrado and AFD.Thus, PEMA is clearly SDNF belonging to the inland Atlantic Forest Domain [26].This forest is conditioned to dual climate seasonality: a season with intense summer rains, followed by a dry period [26,43].A total of 68% of the PEMA species also occurred in Cerrado.The similarity of SDNF to Cerrado was already reported by Franc ¸oso et al. [30] who found that the Atlantic Forest Domain has the greatest number of flora shared with the Cerrado, and it is the most important neighboring biome, influencing the Cerrado floristic composition.
The Atlantic Forest Domain is one of the most threatened tropical biomes, with much of the forest in small and isolated remnants (less than 50 ha) [44].In general, the AFD is extremely fragmented, with only 11.7% from its original cover [4], mainly the Seasonal Dry Neotropical Forests [12].This forest destruction is caused mainly by agricultural expansion [45], occurring in Brazilian central region and ecotones areas of Cerrado and Atlantic Forest Domain [28], resulting in biodiversity loss [11].This study emphasizes the importance of floristic inventories and biodiversity assessments, necessary to understanding the current richness and conservation of forest biodiversity [43].Therefore, the biological knowledge is important for guidance of conservation polices [30], and a holistic approach is necessary to solve the conservation problems [46].Thus, PEMA is extremely important for biological conservation due to attributes such as high biodiversity.For example, in the fauna group, PEMA houses at least 23 species of medium and large mammals, seven of which are listed as endangered in Brazil [47].For the plant group, this reserve has at least six endangered species [48].Therefore, this protected area shelters 13 endangered species of plants and animals, showing their importance for biodiversity maintenance.

Conclusions
PEMA is an important reserve for the conservation of the biodiversity of Seasonal Dry Neotropical Forests, currently threatened by human activities.The reserve contains at least 13 threatened species of plants and animals.In addition, it has a high biodiversity and, because this forest is well conserved, is a priority in conservation and management actions.Thus, this study provides data for the development of a management plan and the conservation of PEMA biodiversity.