The importance of Serra do Mar State Park for liverworts conservation in the Atlantic Rainforest

Serra do Mar State Park (PESM) is located in southeastern São Paulo state, Brazil, and is the largest Atlantic Rainforest conservation area in the country. The park is divided into 10 nuclei, and the Itutinga-Pilões nucleus (NIP) was selected for study since no survey of liverworts species richness had yet been conducted there. The floristic similarities between the NIP and different areas of Atlantic Rainforest in São Paulo state were also assessed. One hundred and eighty liverworts species were identified in the three vegetation types (lowland, submontane, and montane ombrophilous forests) encountered in the NIP, distributed among 62 genera and 21 families. Lejeuneaceae showed the highest species richness with 80 species. The high number of epiphyllous species found in the study area (26% of all species) was notable. In terms of their worldwide distributions, 57% of the species are Neotropical. Clustering analysis showed that the areas of the PESM and Jureia-Itatins Ecological Station were grouped together with the highest similarity values. The liverworts flora of the NIP demonstrates the importance of that nucleus for the conservation of liverworts diversity in the Atlantic Rainforest of the São Paulo state, as well as in Brazil.


Introduction
Approximately 1,550 species of bryophytes are recognized for Brazil, of which 661 are liverworts (Marchantiophyta), among then 558 species are found in the Brazilian Atlantic Rainforest, with 415 recorded for São Paulo state (Bryophytes in Flora do Brasil 2020 under construction).
See supplementary material at <https: //doi.org/10.6084/m9.figshare.13017746.v1> Our current knowledge concerning liverworts species in the Atlantic Rainforest of São Paulo state reflects the contributions of Puiggari (1881-four species); Loefgren (1896 -25 species), Schiffner & Arnell (1964 -403 species), and Hell (1969 -30 species). Starting in 1989, several floristic and ecological studies were carried out in that state (Giancotti & Vital 1989;Visnadi & Vital 1989;Vital & Visnadi 1994;Rebelo et al. 1995;Visnadi 1998Visnadi , 2005Santos 2011;Santos et al. 2011;Visnadi 2011Visnadi , 2012Visnadi , 2013aVisnadi ,b, 2015, encompassing approximately 360 species of liverworts. In contrast, there has been only three studies with the liverworts of Serra do Mar State Park. The Serra do Mar State Park (PESM) was created in 1977 to help preserve remnants of the Atlantic Rainforest in the Serra do Mar mountain range of São Paulo state. It is the largest conservation area of Brazilian Atlantic Rainforest covering 332,000 hectares and encompassing 25 municipalities . The park was divided into 10 nuclei, and the Itutinga-Pilões (NIP), in the central area of the park, was selected for the present study as no survey liverworts species richness had yet been conducted there.
As such, this represents the first investigation providing an overview of the liverworts flora of Itutinga-Pilões nucleus, and incorporates new reports of liverworts taxa. We aimed analyze the liverworts species richness, floristic composition, substrate colonization, phytogeographic patterns in different vegetation types found there, and assessed the floristic similarities between the NIP and different areas of Atlantic Rainforest in the São Paulo state.

Study area
The Itutinga-Pilões nucleus is located in the Serra do Mar State Park, wich borders eight cities (Cubatão, Mogi das Cruzes, Praia Grande, Santos, Santo André, São Bernardo do Campo, São Paulo, and São Vicente) and covers 43,800 ha, with altitudes ranging from 5 to 1,020 m a.s.l., with average annual rainfall of approximately 3,000 to 5,500 mm .

Data collection and identification
Three hundred and thirty-five samples from the study area were encountered in the HUSC and SP herbaria. Most of these samples were collected by two researchers from the Institute of Botany of São Paulo, Daniel Moreira Vital from 1974 to 1989 along the Mogi river valley (20-800 m) and Dr. Olga Yano from 1991 to 1999 on a section of the Imigrantes Highway (ca. 500 m) and Calçada do Lorena (500-800 m). In addition, some samples collected by Alfons Schäfer-Verwimp and Zélia Rodrigues de Mello (SP and HUSC) were studied.
Six field expeditions were made in the different vegetation types of the NIP, between 2016 and 2017, one for lowland forests, two for submontane forest, two for montane forest, and one for the riverbanks on the three vegetions. The collections were made by randomly searching through all of the available microhabitats and substrates. Samples were collected on the tree trunks at heights up to two meters. The procedures of collecting and herborization of material followed the methodology described by Yano (1984). All voucher specimens were deposited in the RB herbarium, with duplicates in HUSC.

Data analysis
The results of the floristic analyses are presented in alphabetical order by family, genera, and species, including vegetation type, elevational range, substrate, Brazilian and worldwide distributions, and voucher.
Liverworts floristic compositions were compared among six different areas from São Paulo state that contain ombrophilous dense forests among their vegetations (Tab. 1), calculating their similarities using the Sörensen coefficient and the dendrogram were made using the UPGMA (unweighted pair group method analysis), performed on PAST software (Hammer et al. 2001). The Sörensen index was chosen because it is a qualitative index that gives more weight to the species that are common to the different samples and not those that only occur in a sample.

Species richness
A total of 831 samples were analyzed, 496 were collected in the present study (97 from lowland forest, 222 from submontane forest, and 177 from montane forest), and 335 samples were encountered housed at the SP and HUSC herbaria (112 from lowland forest, 87 from submontane forest, 47 from montane forest, and 89 with no vegetation type specified on the herbarium label).
Analyzes of liverworts species richness in the three vegetation types showed 88 species from lowland forests (22 exclusive; 24%); 111 from submontane forests, (37 exclusive; 33%); and 96 from montane forests (31 exclusive; 32%). Thirtysix species occurred in all three vegetation types. The submontane forest therefore had the highest species richness and number of exclusive taxa. Those results were different from Costa & Lima (2005), Santos (2008), and  for the Atlantic Rainforest in southeastern Brazil, where the montane forests concentrate the highest number of species. That difference may reflect the fact that our study did not sample the forest canopy or a necessity of more sampling efforts in the montane forests.

Floristic composition
A total of 21 liverwort families were found representing 68% of the families known to São Paulo state and 52.5% of those known to Brazil. In terms of their number of taxa, the most well represented families were Lejeuneaceae (80 spp. -45% of the total species number), Plagiochilaceae (14 spp. -7.8%), Lepidoziaceae (12 spp. -6.7%) Metzgeriaceae (11 spp. -6.1%), and Aneuraceae (11 spp. -6.1%) -altogether accounting for 70% of the total taxa. The three families with the greatest representation [Lejeuneaceae (26% of the total taxa known for Brazil), Plagiochilaceae (57%), and Lepidoziaceae (25%)] are common in all floristic surveys undertaken in tropical forests (Gradstein & Pócs 1989). Costa (2008) recognized 26 species of the family Metzgeriaceae for Brazil, and considered the Atlantic Rainforest as a center of its diversity (46% of total taxa for Brazil). The NIP harbors 41% of the Brazilian species of Metzgeriaceae. The family Aneuraceae has 15 species recognized for Brazil (three species of Aneura and 12 of Riccardia -Bryophytes in Flora do Brasil 2020 under construction), and 10 species found in the NIP (83%). Those two families are among the most well represented families in the study area, being the species of Aneuraceae almost always found in very humid places, near waterfalls or water courses, while Metzgeriaceae were also found in humid places so as in the understoryes, mainly in living trunks, and both were found in the three vegetation formations.
The family Lejeuneaceae was wellrepresented in the three vegetation types of the NIP. That result was expected, and as it that specially species-rich in the Atlantic Rainforest (Costa 2009), and concentrates 70% of all liverworts species encountered in floristic inventories in the tropical Americas (Gradstein et al. 2001) and in the Atlantic Rainforest of the São Paulo state (Visnadi 2005;Yano & Peralta 2007;Peralta & Yano 2008;Visnadi 2009Visnadi , 2012Visnadi , 2013aVisnadi ,b, 2015.
The family Trichocoleaceae was only found in the montane forest sites above 700 m. That result was similar to reports by Visnadi (1998), Santos (2011 that also found it in the montane forests of São Paulo state. The most representative genera in NIP were Lejeunea (21 species); Plagiochila (13 species); Metzgeria (11 species); Riccardia and Cheilolojeunea (10 species each); Cololejeunea, Drepanolejeunea, and Radula (seven species each), and according to Gradstein & Pócs (1989) and Gradstein et al. (2001) those are the principal genera found in most floristic surveys in the tropics. Other well-represented genera in our survey were Metzgeria and Riccardia, which have their known centers of diversity in southeastern Brazil (Costa 2008;Santos 2008).
The high species richness found in the genera Riccardia, Lejeunea, Metzgeria, and Plagiochila demonstrated the importance of that Atlantic Rainforest remnant in São Paulo state for liverworts conservation -as more than 40% of the liverworts species known to São Paulo state, and more than 30% for the Atlantic Rainforest species, have been recorded here.
The present study demonstrated that new collection efforts in many areas of São Paulo state can still evidence other novelties similar to those presented below.
Prionolejeunea scaberula (Spruce) Steph. was cited by Costa & Peralta (2015) for the São Paulo state, but without a voucher, in the present study was encountered in lowland forests.
Rectolejeunea truncatilobula C. Bastos is cited here for only the second time in 35 years for São Paulo state (Ilha do Cardoso), it was encountered in submontane forest.
Plagiochila aerea Taylor is a montane Atlantic Rainforest species, recorded here for the first time to São Paulo state.
Vitalianthus bischlerianus (Pôrto & Grolle) R.M.Schust. & Giancotti is endemic to the Brazilian Atlantic Rainforest. It was found here for the first time growing on living leaves, but is more typical of tree trunks, and is considered here a facultative epiphyllous species.
The high number of epiphyllous species encountered (26% of the total number) was remarkable, and represents fully 39% of the total number of the epiphyllous liverworts species recognized for Brazil (Bryophytes in Flora do Brasil 2020 under construction). They were found in the three vegetation formations, and according to Gradstein (1992), epiphyllous bryophytes comprise a threatened category in anthropogenically impacted environments due to their sensitivity to disturbances and their preference for preserved areas, with species richness in plantations and secondary forests being much lower than in primary forests. Epiphyllous species require low solar radiation levels, high water retention by the epibiont leaf surfaces, and well preserved environments. We therefore consider the NIP forests as well preserved.
The predominance of the Neotropical species is common in floristic surveys undertaken in Brazil (Costa & Silva 2003;Santos & Costa 2010;Visnadi 2012;. Sixteen encountered taxa are known to be endemic to Brazil, of which 11 species are endemic to Brazilian Atlantic Rainforest (ca. 20% of the total number of endemic liverworts recognized for that biome) (Bryophytes in Flora do Brasil 2020 under construction). They were found colonizing living trunks (10 spp.), leaves (four spp.), rocks (four spp.), soil (three spp.), and dead trunk (one spp.). Those results also demonstrate the importance of the NIP for the conservation of the endemic species from the Atlantic Rainforest, which is considered a center of endemism for liverworts in Brazil (Gradstein & Costa 2003).

Floristic similarities
Analyzes of the similarities between the liverworts compositions of six different areas, demonstrated that the floristic affinity between the six areas varied from 31% to 63% (Tab. 3). The highest similarities were observed among areas of Serra do Mar State Park, while the lowest similarity was between PESM-NSV (Santa Virginia Nucleus) and RBASP (Alto da Serra de Paranapiacaba Biological Reserve) (the areas with highest and lowest species richness respectively).
The areas PEI (Intervales State Park) and RBASP were considered to be poorly sampled in light of the low numbers of species found (83 and 68 spp. respectively), so that the results of the cluster analysis could be different if new surveys were carried out.
Clustering analysis revealed the existence of a group with similarity values varying between 52% and 63% [three areas in the PESM (NSV, NPC and NIP) and one area in the EEJI (Juréia-Itatins Ecological Station) (Fig. 2). Probably those four areas belong to the same Atlantic Rainforest continuum. Rodriguésia 71: e01442018. 2020 The two areas with the highest similarity were NIP and NPC (63%). According to IF (2008), arriving cold fronts tend to retreat and stagnate before dissipating, resulting in a very high rainfall rates and similar climates in both areas. Additionally, we observed that those two nuclei have the same vegetation types and elevational ranges -which probably contributed to the grouping of these areas.

Conclusion
The liverworts flora found in NIP demonstrates the importance of the nucleus for the conservation of hepatic diversity in the Atlantic Rainforest of the state of São Paulo and Brazil, since in NIP occurs 42% of the known liverworts species to São Paulo and 32% to Atlantic Rain Forest of Brazil.
We consider the studied area is in good state of conservation, since some of the main liverworts families of Atlantic Rain Forest are well represented, such as Metzgeriaceae, Plagiochillaceae, and Aneuraceae. In addition, a large number of epiphyllous species were found in the study area, a group threatened in disturbed environments due to high sensitivity to environmental disturbances (changes in humidity, luminosity and temperature) and with preference for preserved, humid and shaded sites.     Table 1.