Inventory of Ferns and Lycophytes of the RPPN Pedra D ’ Antas , Pernambuco state , northeastern Brazil

The Northeastern Atlantic Forest (NAF) has a historic of intense habitat loss and fragmentation. In this context, knowledge of the species from forest remnants is urgently needed and represents a key tool for future studies and conservation strategies. Here, we present the floristic inventory of ferns and lycophytes from the Private Natural Heritage Reserve RPPN Pedra D’Antas, located in a NAF area. The study area associated with the RPPN Frei Caneca is the Serra do Urubu, which is a hotspot for the diversity of several biological groups in the NAF. We recorded 74 fern species, distributed in 17 families and 46 genera. The most diverse families were Pteridaceae (17 species), Polypodiaceae (14 spp.), Dryopteridaceae (nine spp.) and Thelypteridaceae (seven spp.). Lycophytes were represented by four species, two families and two genera. A new record for the Northeast of Brazil, Serpocaulon hirsutulum, is presented in this study. The area has a large number of species, some of which are restricted to the NAF (e.g. Megalastrum umbrinum). Based on the richness of the study area associated with another inventory held at the RPPN Frei Caneca (138 spp.), the Serra do Urubu is corroborated as a hot-spot for the diversity of ferns and lycophytes in the NAF.


Introduction
The number of floristic inventories for the various ecosystems of the Brazilian territory has grown in recent decades, as evidenced by the Forzza et al. 2010.However, thorough knowledge of the high plant diversity occurring in the country, which is highly threatened by many anthropogenic pressures, still requires more efforts.Inventories are the means by which such knowledge is achieved (Magurran 2004).They allow recognizing the areas that hold highest richness as well as update the floras and biogeographical patterns of distribution of species (e.g.new records of species and/or species with restricted distribution), which represents key information for several biological studies and future conservation strategies (see Prado & Hirai 2011, Gasper et al. 2012), identifying forest remnants most important to conservation on a given geographic or politic scale.
The need for more inventories is stressed by the excessive loss of species caused by intense levels of degradation in Brazilian ecosystems.It is likely that some species may disappear even before registration at local, regional or national level.Particularly, the Northeastern Atlantic Forest (NAF) in Brazil (region north of the São Francisco River, covering the States of Alagoas, Pernambuco, Paraíba, Rio Grande do Norte, and enclaves in Ceará State) has a notorious scenario of intense habitat loss and fragmentation resulting from a long historical period of disturbances.Furthermore, few protected areas have been established in this biogeographical unit, which is recognized by its high vulnerability and loss of species (Tabarelli et al. 2006, Ribeiro et al. 2009).
The Serra do Urubu comprises two protected areas: the Private Natural Heritage Reserve (Reserva Particular do Patrimônio Nacional -RPPN) Frei Caneca and the RPPN Pedra D'Antas, and represents one of the last largest forest NAF remnants, with approximately 1000 ha.This area has high species richness and endemism, being considered a hotspot for biodiversity of flowering plants in the NAF (Melo et al. 2016), and one of the most important areas for bird conservation in the Neotropics (SAVE Brasil 2016).Moreover, the RPPN Frei Caneca has the highest richness of ferns and lycophytes, the seedless vascular plant groups, ever recorded to a NAF (138 spp.) (Lopes 2003).Here, we present the inventory of the ferns and lycophytes flora of the RPPN Pedra D'Antas, where a first record of Serpocaulon hirsutulum for the northeastern Brazil is reported and the status of the Serra do Urubu as a hotspot for ferns diversity in NAF is confirmed.

Study area
The RPPN Pedra D'Antas (8°42'14''S -35°51'10''W, max.alt.: 800 m) is located in Lagoa dos Gatos (47.25% of the area), Jaqueira (6.72%) and São Benedito do Sul (46.03%) municipalities of the State of Pernambuco, northeastern Brazil.The area presents approximately 325 hectares of Open Ombrophylous Atlantic Forest in diverse stages of preservation (Figure 1).The relief of the area is hilly with flat tops, steep slopes and narrow valleys.The area has predominantly sandy-clay, yellowish red argisol soil (IBGE 1995).There are several perennial water bodies of the Una River Basin (CPRM 2005).The local climate is tropical moist as with hot and dry summer and rainy winter, according to Koppen classification (1948).The average annual rainfall is approximately 1,345 mm.The annual average temperature is 23.6°C, ranging from 18°C to 30°C (CPRM 2005).

Inventory
Fifteen trips were carried out from October/2011 to January/2013 to the study area.On each trip, the forest fragment was explored through systematic walks, georeferencing points with GPS and giving priority to the preferential environments for establishment of ferns and lycophytes (e.g.forest edge and interior, areas near streams and other water bodies, ravines, valleys and slopes and rocky areas).Besides the systematic exploration of these environments, random walks were also conducted to cover the most of the forest fragment area.Collection and herborization of specimens followed the usual techniques for vascular plants (Mori et al. 1989).Voucher specimens were incorporated into the UFP herbarium collection.Identification was carried out with aid of specialized bibliography, consultation with specialists and comparison with herborized material from the UFP herbarium determined by specialists.The classification presented follows the Pteridophyte Phylogeny Group (PPG 2016).The names of the authors of the species were abbreviated according to the Flora do Brasil (2020).
Field notes at the collection site of specimens were taken, ranking the species in the following categories: terrestrial, rupicolous, hemiepiphyte and holoepiphyte (Salvo Garcia & Verdugo 1990).For comparison of species richness in the study area with other areas, we consulted the available inventories in the NAF.Comments about some taxa (distribution and taxonomic characteristics) were based on cited literature.

Results and Discussion
Seventy-four species of ferns (Polypodiospsida Class), representing 46 genera and 17 families were recorded in the RPPN Pedra D'Antas (Table 1).As for lycophytes (Lycopodiopsida Class), four species in two families and two genera were recorded (Table 1).The fern and lycophyte richness of the study area (79 spp.) can be considered high when contrasted to other NAF areas (Table 2).This number of species represents about 36% of the richness of ferns and lycophytes estimated for the state of Pernambuco (214 spp.) according to Prado et al. (2015).This emphasizes the relevance of preserving the area for the conservation of the studied groups.
The fern and lycophyte flora of the present area is mostly composed of species common to other NAF inventoried areas (e.g.Santiago & Barros 2003, Xavier & Barros 2003, Santiago et al. 2004, Xavier & Barros 2005, Pietrobom & Barros 2006, Pereira et al. 2011, Pereira et al. 2013).However, some taxa are not usually registered in NAF, such as Megalastrum umbrinum (Farias et al. 2015), which has been found only in the present area, as well Elaphoglossum glabellum and Ctenitis glandulosa, which had few records in this unit and were previously recorded in two other NAF areas.
In addition, Serpocaulon hirsutulum was found, representing a new record for the Northeast of Brazil.The species S. hirsutulum (see characteristics in Schwartsburd & Smith 2013) has distribution restricted to the states of Minas Gerais, São Paulo (southeast) and Pernambuco (northeast).In the latter, it is recorded in two areas (i.e.Serra do Urubu): the RPPN Frei Caneca (recently determined and unpublished material) and the present studied area.
Only one exotic species was recorded in the RPPN Pedra D'Antas: Macrothelypteris torresiana.This species is native from Madagascar, Japan, Indonesia, Thailand, Malaysia, Queenslândia (Robinson et al., 2010), and it is widely naturalized and often collected in Brazilian forests, particularly in the areas of the Atlantic Forest and Cerrado, according to Salino & Almeida (2015).As for the types of habitat, terrestrial species (55%) were predominant.This result supports the majority of fern and lycophyte inventories in the NAF (e.g.Santiago & Barros 2003, Xavier & Barros 2003, Santiago et al. 2004, Xavier & Barros 2005, Pietrobom & Barros 2006, Pereira et al. 2011, Pereira et al. 2013).This pattern of predominance of terrestrial habitat can be explained by the diversity of favorable conditions promoted by this substrate, such as water availability, shade, as well as greater availability of nutrients (Sota 1971).
The high richness recorded here for the RPPN Pedra D'Antas and reported by Lopes (2003) for the RPPN Frei Caneca supports the concept this area as a hotspot for the fern and lycophyte diversity in the NAF.As a consequence, the importance of effective protection of the area is reinforced.Biota Neotrop.,17(4)

Figure 1 .
Figure 1.Part of the RPPN Pedra D'Antas, a remnant of Open Ombrophilous Atlantic Forest, situated in state of Pernambuco, northeastern Brazil.
*Specimens with sterile material.

Table 2 .
Ten inventories of Ferns (Polypodiopsida) and Lycophytes (Lycopodiopsida) performed Northeastern Atlantic Forest with greatest number of species recorded.