Lycophytes and ferns composition of Atlantic Forest conservation units in western Paraná with comparisons to other areas in southern Brazil

This study surveyed lycophyte and fern species in four forest fragments in western Paraná, Brazil, and compared them to 15 other fragments with different plant formations from the Atlantic Forest biome in southern Brazil. In total, five lycophyte species (in two families and two genera) and 98 species and two varieties of ferns (in 16 families and 38 genera) were registered in the four fragments. The most represented families were Pteridaceae (23 spp.), Polypodiaceae (18 spp.), Aspleniaceae (13 spp.), and Thelypteridaceae (11 spp.). Asplenium (12 spp.), Thelypteris (10 spp.), and Blechnum (seven spp.) were among the most represented genera. The occurrence of Dicksonia sellowiana was noteworthy because it was associated with seasonal semideciduous forest and is threatened in Brazil. Similarity among areas was determined by a cluster analysis (UPGMA and Sørensen’s index) and the relation between similarity and geographic distance was determined through Matel’s analysis. The analyses revealed greater similarity among the four study areas and, for these areas as a whole, greater similarity to fragments in Rio Grande do Sul, which is evidence that these areas have similar environmental conditions.


Introduction
Lycophytes and ferns are represented by about 13,600 species.The distribution of these groups follows a pattern known as the latitudinal gradient of diversity, where in both hemispheres, from poles to equator, the number of species per unit area increases more than 30 times (Moran 2008).However, pteridophyte richness is not regular, and around 75% of this group occurs in tropical and subtropical humid regions (Tryon & Tryon 1982).
The Atlantic Forest is one of the 34 global "hotspots" of biodiversity (Mittermeier et al. 2004), is the second largest tropical forest in the Americas, and originally extended continuously along the Brazilian coast, to eastern Paraguay and northeastern Argentina at its southern limit (SOS Mata Atlântica 2015).In Brazil, it is regarded as one of the richest biomes in plant diversity where there are 15,782 species, of which 7,155 are endemic (Stehmann et al. 2009).Out of the total number of species in the Atlantic Forest, 840 are lycophytes and ferns (Salino & Almeida 2009).
The high environmental diversity of the Atlantic Forest is thought to be the cause of the species richness, diver-sity, and high degree of endemism in this biome (Silva & Casteleti 2005).Latitude varies significantly along the Atlantic Forest, which, unlike other tropical forests, stretches more than 27 degrees.Elevation is also an important factor, which ranges from sea level to 2,700 m (Rizzini 1992).In addition, there is longitudinal variation, where inland forests differ significantly from those near the coast; the more inland the forests are, the more seasonal they become (Oliveira-Filho & Fontes 2000).
Species composition varies widely because of environmental diversity.MacArthur & Wilson (1967) pointed out that geographical proximity influences floristic similarity and, according to Oliveira-Filho & Fontes (2000), different forest formations in the Atlantic Forest have different plant species compositions.Thus, for biodiversity conservation purposes, the Atlantic Forest cannot be addressed as a homogeneous unit and there is a need to take into account the various forest types found in this biome.As defined by Veloso et al. (1991), this biome has the following plant formations: rainforest, Araucaria forest, semideciduous forest and deciduous forest, as well as associated ecosystems, such as mangroves, restinga, high Acta bot.bras.29(4): 499-508.2015.altitude grasslands, inland swamps, and forest enclaves in the Northeast Region.
In Paraná, the remaining Atlantic Forest is restricted to a few publicly and privately protected areas, such as Parque Nacional do Iguaçu, Parque Nacional de Ilha Grande, Parque Estadual São Camilo, Parque Estadual da Cabeça do Cachorro, Parque Estadual do Rio Guarani, and the private nature reserve Fazenda Santa Maria.Most of these areas are included in the Iguaçu-Paraná Biodiversity Corridor, located in the Iguaçu and Paraná III river basins (Tossulino et al. 2007).
The aim of this study was to survey the ferns and lycophytes in Parque Estadual Cabeça do Cachorro (PECC), Parque Estadual do Rio Guarani (PERG), Parque Nacional do Iguaçu (PNI) and Fazenda Santa Maria (FSM), and to analyze the floristic similarity among these four areas and other areas of Atlantic Forest in southeastern and southern Brazil.This study considers the hypothesis that areas with similar forest formations have a similar floristic composition, regardless of their geographical proximity (MacArthur & Wilson 1967;Oliveira Filho & Fontes 2000).

Study areas
The study was conducted in four protected areas (Fig. 1).In these regions the climate is characterized as mesothermal humid subtropical, which is CFA in Köppen's classification (Köppen 1931), with an average annual temperature of 21ºC.
Summers have an average temperature of over 22ºC and winters have an average below 18ºC.Rainfall is well distributed throughout the year, decreasing slightly in the winter, and annual rainfall is around 1,800 mm (IAPAR 2015).Soils are predominantly dark red, purple, and dark brown latosols, with a deep profile and high fertility (Larach et al. 1984).
The dominant vegetation in the four areas is semideciduous forest; however, in Parque Nacional do Iguaçu there is also a portion that is predominantly transitional vegetation between semideciduous forest and Araucaria forest (Roderjan et al. 2002;IBGE 2012).

Floristic survey
The floristic survey was conducted between August 2010 and September 2013.In Parque Estadual Cabeça do Cachorro and RPPN Fazenda Santa Maria, the existing trails were surveyed, totaling about 3.5 Km in each area.For the Parque Nacional do Iguaçu, 20 trails were surveyed, totaling about 50 km.In Parque Estadual do Rio Guarani, seven Acta bot.bras.29(4): 499-508.2015.trails were surveyed, totaling about 17 km.Sampling was done in an unsystematic way in order to go through all of the vegetation types.Information regarding the habitat and habit of collected plants was recorded.
The plants were collected and processed according to standard techniques for lycophytes and ferns (Bridson & Forman 1998) and the specimens were archived at UNOP (Universidade do Oeste do Paraná) and BHCB (Thiers 2015).Additional specimens from BHCB and MBM (Thiers 2015) were included in the study.
Species were identified using the literature and herbarium specimens.For lycophytes, the classification system proposed by Kramer & Green (1990), with modifications by Øllgaard (2012), was used.The classification of ferns was based on Smith et al. (2006), with modifications by Rothfels et al. (2012) for Woodsiaceae.Author names of taxa were abbreviated according to the International Plant Names Index (IPNI) (Brummit & Powell 1992).

Similarity
The list of lycophyte and fern species in the sampled areas (Parque Estadual Cabeça do Cachorro, Fazenda Santa Maria, Parque Nacional do Iguaçu, and Parque Estadual do Rio Guarani) was compared to 15 other, previously published lists (Tab. 1) for Atlantic Forest areas in southern Brazil (Fig. 1).
To compare the floristic similarity, we constructed a presence/absence matrix of species (Tabs.1-2).A cluster analysis was performed with this matrix, which resulted in a dendrogram, by using the algorithm unweighted pair-group method using arithmetic averages (UPGMA) and Sørensen's index (Bray-Curtis) (Gotelli & Ellison 2011).To assess the deformation degree caused by the dendrogram construction, the cophenetic correlation coefficient was calculated (Hammer & Harper 2006).Analyses were conducted using the software Palaeontological Statistics (PAST) (Hammer et al. 2001).
To test the hypothesis that closer areas are more similar regarding their composition, Mantel's test was chosen because it is a test where the predictor variable is space, measured as geographical distance (Hammer & Harper 2006).

Floristic survey
In the four protected areas surveyed, 105 taxa (103 species and two varieties) were recorded.Of these, five species are lycophytes and 98 species and two varieties are ferns.The lycophytes are represented by two families, Selaginellaceae and Lycopodiaceae, each with one genus (Tab.2).The ferns are distributed among 16 families and 38 genera (Tab.2).Of the four areas, the fragment with the largest number of species was Parque Nacional do Iguaçu (101 species), followed by Parque Estadual do Rio Guarani (60 species), the private nature reserve Fazenda Santa Maria (40 species), and Parque Estadual Cabeça do Cachorro (38 species) (Tab.2).The species richness found in the four areas is similar to that reported in studies conducted in areas with the same vegetation type, especially in southern Brazil (Schmitt et al. 2006;Lehn et al. 2009).
Most of the registered species (about 60%) are widespread and have been recorded in other areas in Paraná (Dittrich et al. 2005;Salino et al. 2005;Sakagami 2006;Schwartsburd & Labiak 2007;Michelon & Labiak 2013).The remaining 42 species (40%) are restricted to particular vegetations.This is possibly due to the influence of environmental factors, such as soil type, physical structure, and microclimate, which usually affect species distributions (Zuquim et al. 2012).Of the four areas studied, PNI is the only fragment that has two forest formations, where 11 taxa (10.47%) were registered only in Araucaria forest and 31 species (28.57%) were collected only in semideciduous forest (Tab.2).
Regarding geographical distribution, 76% of the taxa are well distributed in the Neotropics, 11% are Pantropical species and 13% are species restricted to Brazil: Asplenium kunzeanum, A. pulchellum, Cyathea atrovirens, C. phalerata, Diplazium herbaceum, Hypolepis stolonifera, Megalastrum connexum, Pecluma sicca, P. truncorum, Pleopeltis pleopeltifolia, Polyphlebium diaphanum, Pityrogramma chaerophylla, Serpocaulon vacillans, and Thelypteris recumbens (Tab.2); the latter has a rather restricted distribution and is endemic to southern Brazil (Prado & Sylvestre 2015).There was a predominance of widely distributed species.Possibly, the absence of local endemic species is due to the location of the study areas because they are further inland and south, with a subtropical climate, which are characteristics that are not typical of endemism (Given 1993;Moran 2008).
Dicksonia sellowiana is a threatened species (Santiago et al. 2013) that usually occurs in association with Araucaria forest and rainforest at elevations between 600 and 2,200 m (Santiago et al. 2013).However, it may occur in deciduous forest (Gasper et al. 2011) and gallery forest (Salino & Viveros 2012).In this study this is species was observed both in Araucaria forest (PNI) and in semideciduous forest, noteworthy, its first record (PERG) between 300 and 400m altitudinal height.
Five species (Macrothelypteris torresiana, Nephrolepis cordifolia, Thelypteris dentata, Pteris vittata, and Deparia petersenii) found in the study areas (two species in PERG, one in PECC, and five in PNI) are exotic or naturalized (Moro et al. 2012), of extra-American origin, and occur spontaneously or sub-spontaneously in Brazil.
Adiantopsis perfasciculata and Blechnum lanceola are new records for the state of Paraná.Adiantopsis perfasciculata was cited only for Central Brazil, the state of Minas Gerais (Figueiredo & Salino 2005;Prado 2015) and, in the South Region, the states of Rio Grande do Sul and Santa Catarina (Sehnem 1972;Gasper et al. 2012).Blechnum lanceola was previously recorded for the Central, Southeast, and South regions of Brazil, but in the latter region it was only known from Rio Grande do Sul (Dittrich 2005;Dittrich & Salino 2015).

Similarity
The cluster analysis (Fig. 2) showed high statistical significance and the cophenetic correlation coefficient was 0.8758, indicating that distortion between the similarity matrix and multidimensional space shown in the dendrogram was small (Hammer & Harper 2006).
The dendrogram shows the formation of two groups.A larger group (group I) comprises 10 areas in Paraná, including the studied areas, one area in Santa Catarina, and five areas in Rio Grande do Sul.The second group (group II) comprises two areas in Rio Grande do Sul (LPV and PET) and one in Paraná (MG) (Fig. 2).
According to Mantel's analysis, differences in floristic composition between selected areas are not related to geographical distance because the test showed that geographical distance between locations was negative and strongly insignificant (p = 0.432 [p > 0.01] and r = 0.0579).
The fragment São Francisco de Paula (SFP) does not occur with any other group, behaving as an outlier in the analysis.This fragment is located in an urban area in Rio Grande do Sul and more than half of the species from this survey (about 25) are different from those found in the studied areas.
Within group I, there are two subgroups (A and B).In subgroup A, the fragments PEcK (PR), PEVV (PR), PEG (PR), SMPr (PR), PNSI (SC) cluster on one branch and IM (PR) is alone on a separate branch.
Possible reasons why Ilha do Mel (PR) differs from the other areas are its location, elevation above sea level, due to the fact that it is an island (Tab.1), and because it has a forest formation influenced by restinga (Dzwonko & Kornás 1994).
Branch A1 is a cluster of the areas PEcK (PR), PEVV (PR) and PEG (PR), which are about 65% similar in floristic composition (Fig. 2).These three locations share the same vegetation type (Araucaria forest and natural grasslands) (Tab. 1) and are geographically close, which suggests that both of these aspects are strong influences for this cluster.
Branch A2 consists of the fragments SMPr (PR) and PNSI (SC), which are about 62% similar and, although geographically more distant, share the same vegetation type (rainforest).
It is noteworthy that areas from subgroup A (PEcK, PEVV, PEG, SMPr, PNSI, IM) are the most representative in species number because they are located in the far eastern, coastal part of the country (mainly in Serra do Mar) that has unique features, such as the influence of humid winds coming from the ocean and heavy rainfall throughout the year (Pellegatti & Galvani 2010).According to Page (1979), environments with a higher occurrence of lycophytes and ferns are very humid and tropical, and have no dry periods throughout the year.
Branch B1 is exclusively formed by the fragments of this study, FSM, PECC, PERG and PNI (Fig. 2).The fragments FSM and PECC have the highest similarity rate, with about 90% of the same species, and these two areas are 85% similar to the species from PERG (Fig. 2).The floristic composition of PNI is 60% similar to the other three areas combined (Fig. 2).
As found by Mantel's test and the similarity analysis, PNI differs the most for these fragments even though it is geographically closer to FSM (Fig. 1).This might be because PNI is large and has two forest formations.Thus, also in the four areas under study in western Paraná, the greatest similarity was found between fragments with the same forest formation.Additionally, other factors could influence this similarity, such as environmental heterogeneity (Jones et al. 2006;Gasper et al. 2012) and disturbance history (Jones et al. 2008;Nóbrega et al. 2011).
Branch B2 is exclusively formed by the fragments from Rio Grande do Sul (MB, ME, RVT, FLONAC, MR).These areas are mainly Araucaria forest, except for MB, which consists of rainforest, and RVT, which is deciduous forest.Branch B2 comprises two clusters (B2a and B2b), and branch B2a comprises MB, ME and RVT.The floras of fragments MB and ME are 54% similar and these fragments, when compared to the fragment RVT, are 45% similar; RVT is the least similar.Branch B2b comprises fragments FLONAC and MR, which are 54% similar (Fig. 2).The difference of these five fragments in relation to the other areas is evidence that they are grouped according to forest formation (Araucaria forest).
In the group II there is a union of fragments that only have semideciduous forest (MG, LPV and PET).Subgroup C is formed by the fragments LPV and PET, which are 50% similar, and fragment MG is further from the latter two, with about 35% similarity in its floristic composition.
The occurrence of 2 clusters with areas of semideciduous forest (GI and B1), in different branches, could be explained by how the data was collected during the studies of these areas.The studies related to the three areas of group GI were surveys of the entire vascular flora, not specifically lycophytes and ferns, which could have resulted in a sub- sampling of the groups.This is an important bias to consider in relation to the composition of species lists.
Based on the hypothesis proposed, when analyzing the cluster of areas in this study with areas in Rio Grande do Sul (subgroup B), a possible explanation for the existence of similarity might be the influence of Araucaria forest on the species composition within the areas of this study, especially because western Paraná is a transition area between this forest formation and semideciduous forest.There could also be a relationship between the longitude and latitude of these areas, as found for continental inland forests compared to those close to the coast, because the more inland the forests are the more seasonal they become (Oliveira-Filho & Fontes 2000).Since humidity and temperature vary significantly relative to longitude and latitude, for the various phytophysiognomies in the Atlantic Forest, it is possible that areas located further west and further south are less influenced by humidity and have similar environmental conditions.
The results of this study support the hypothesis that areas with similar forest formations have a similar floristic composition, regardless of their geographical proximity.This is supported by evidence in subgroup A, where IM was the least similar fragment, which was mainly due to the presence of restinga in this area (Fig. 2).The hypothesis is also supported in subgroup B, where fragments FSM and PNI are geographically close (Fig. 1) but are only 60% similar in floristic composition (Fig. 2) because Araucaria forest occurs only in PNI.
The results of the similarity analysis reaffirm the fact that species composition is one of the determining factors in the plant community structure present in each forest type within a biome.Patterns found in this study were also found by Nóbrega et al. (2011), Souza et al. (2012), Salino et al. (2013), which supports the hypothesis in this work and the results in the dendrogram.
The remaining Atlantic Forest in western Paraná is known only from a few protected areas and there is a deficiency of pteridophyte studies for this region because the diversity of this group is concentrated in other areas of the state (Cislinski 1996;Dittrich et al.1999;Borgo & Silva 2003).The species richness of the four areas, here surveyed, is lower compared with eastern regions.This w as expected, since the rainforests in the east are richer than seasonal forests.However, this study contributed to the knowledge of lycophytes and ferns because little is known, based on the literature and herbarium collections, about the occurrence and distribution of species of these plants in western Paraná.Therefore, these new data are important for the conservation and management of the remaining Atlantic Forest in Brazil.

Table 1 .
List of the 19 locations included in the floristic similarity analysis of lycophytes and ferns.