Biodiversity of benthic macroinvertebrates on hard substrates in the Currais Marine Protected Area , in southern Brazil

Abstract: This study describes the biodiversity of benthic invertebrates on hard substrates in the Currais Marine Protected Area (Currais MPA), in the state of Paraná. The benthic community was sampled during 2012 to 2015, in winter and summer, at two islands and four groups of artificial reefs (ARs). Samples were collected along shallow (2-4 m) and deep (6-8 m) transects at the islands and ~18 m transects at the ARs. We also searched the literature to review all published records of benthic invertebrates on hard substrates in the Currais MPA. We recorded 176 taxa in the phyla Annelida (class Polychaeta), Arthropoda (class Maxillopoda, order Sessilia), Bryozoa, Cnidaria, Chordata (class Ascidiacea), Echinodermata, Mollusca and Porifera, in 13 classes, 40 orders and 75 families. With these 102 new records, our list comprises 58% of all recorded species. Of these, 58 taxa were first records for the state of Paraná. This remarkable number of new records highlights that biodiversity studies are lacking in Paraná. Fifteen non-indigenous species and one endangered species, the sea star Coscinasterias tenuispina (Lamarck, 1816), are included. This is an important transitional area to monitor expansion or constriction of the latitudinal distributions of species, in the context of climate change, that may influence the geographical distribution of species (both native and invasive). This study is the first inventory of marine hard substrate habitats of the Currais MPA with a surprisingly diverse community.


Introduction
The National Marine Park of Currais Islands is a new Marine Protected Area (MPA, hereafter Currais MPA) that was created in 2013 (Brazilian federal law number 12.829, Brasil 2013).It is the first MPA in the category National Marine Park in the state of Paraná and the third in Brazil (the other two are Abrolhos and Fernando de Noronha, both in northeastern Brazil).Currais MPA is in an area of large economical and ecological importance, because of a major commercial port with international traffic of container ships and oil tankers and because of the extensive system of estuaries with mangroves.The creation of the Currais MPA was based on its importance for seabird breeding (Krul 2004, Carniel & Krul 2010).Previous studies of the marine environment tended to focus on the ichthyofauna (Félix & Harckradt 2008, Félix-Hackradt & Hackradt 2008, Harckradt & Félix-Harckradt 2009, Daros et al. 2012).Only one study examined the soft bottom infauna (Lorenzi & Borzone 2009), three examined benthic invertebrates on hard substrates, one of ascidians (Rocha & Faria 2005) and two experimental studies on temporal colonization of artificial substrates near the islands (Brandini & Silva 2011, Bumbeer & Rocha 2012).Since the creation of the MPA, there has been only one study of marine biota, which examined the algal community (Pellizzari et al. 2014).On a larger scale, invertebrates of hard substrates are very poorly studied along the entire coast of Paraná, and is a major gap in the understanding of species distributions in Brazil.
Hard substrates such as those typically present around coastal islands, rocky shores and calcareous bottoms are uncommon in coastal Paraná.Thus, Currais MPA is ecologically relevant for its hard substrate for communities adapted to reef-like habitats, and because it is less impacted as nearer the mainland.Also, Currais islands was at one time (prior to creation of the MPA) an important area for both recreational and artisanal fisheries and also the main site for recreational scuba diving in Paraná.The Currais MPA is also under the influence of continental drainage from the Paranaguá Estuarine Complex, with anthropogenic impact that potentially threatens local biodiversity, such as contamination by urban and industrial development (Noernberg et al. 2008, Possatto et al. 2014) and bioinvasions (Bumbeer & Rocha 2016).Indeed, the presence of a large port with its ship traffic probably favors the spread of non-indigenous species (NIS) to the open coastal environment, including Currais MPA (Bumbeer & Rocha 2016).
Understanding the benthic communities on hard substrates is critical because this environment has been heavily disturbed by human activities, potentially leading to decline in biodiversity and to irreversible loss of biological information.Despite this importance, three years after its establishment, no management plan has been developed for MPA Currais.During the same time interval, development on the mainland has been growing rapidly, including the construction of a new port for containers that will increase by 55% the port capacity in the state and is scheduled to start activities in 2018 (http://portopontal.com.br).Therefore, in this scenario it is clear that establishing baselines of community composition and distribution on all types of habitats is very important within MPA Currais, including benthic communities, in order to monitor and understand future changes.Here we provide the first inventory of the benthic macroinvertebrate species on hard substrates of the Marine Protected Area of Currais, including the sessile community and sedentary vagile organisms (i.e., Gastropoda, Polychaeta and Echinodermata).

Material and Methods
The National Marine Park of Currais Islands is located 6.2 miles from the coast, between two estuaries, Guaratuba Bay and the Paranaguá Estuarine Complex (Figure 1).With a total area of 1400 ha, the MPA includes three islands (Grapirá, Três Picos and Filhote) and four groups of artificial reefs (ARs) (concrete blocks placed on the seabed to provide new environments for encrusting communities).The depth along the archipelago varies from 1.5 to 16 m, with natural hard substrates usually up 10 m.The inclination of the rocky shores is moderate, between 45 o and 60 o (Daros et al. 2012).The artificial reefs were placed in 1997 on the sandy bottom at a depth around 18 m.
The benthic community was sampled at two islands, Grapirá and Três Picos, and four ARs.Sites of different depth and wave exposure were sampled to include a wider variety of environmental conditions.At each island, two sites were chosen, one exposed to the open sea and another sheltered from the main wave train by the island.Each of the four sites were surveyed in shallow (around 2 -4 m) and deep (6 -8 m) transects, while artificial reef sites were surveyed in two transects at ~18 m (Table 1).
Sites were sampled during 37 SCUBA dives, between July 2012 and January 2015 (Table 1), during summer and winter to include possible seasonal variation in abundance of species.During dives, we actively searched for all relevant species within the area of the transect (20 m long vs. 2 m wide), photographed and individuals and colonies were manually collected for identification.Horizontal, vertical and negative surfaces were sampled, as well as crevices and under rocks.Upon collection, samples were treated with a menthol solution in seawater for relaxation of the fauna and were subsequently fixed in 4% formalin for taxonomical study by specialists.The Mollusca were deposited in the Zoology Museum of University of São Paulo (MZUSP), Porifera in the National Museum of University of Rio de Janeiro (MN-UFRJ), Cnidaria and Tunicata in the collection of the Zoology Department of the Federal University of Paraná (DZUP).
A search of the literature was also conducted to review all published records of benthic invertebrates on hard substrates in the area of the Currais MPA.The species recorded on both field survey and previous studies were indicated if found in natural substrata of islands, ARs or recruitment plates.The status of bioinvasion and endangered species were also indicated according to literature and Brazilian official lists (Lopes 2009, MMA 445/14).
New records (n = 102) for the MPA area include 58% of all recorded species.Of these, 58 were not previously recorded for Paraná.Except Arthropoda, new records were found for all phyla, mainly Porifera (n = 20).Additionally, some species have not yet been described.Examples in Polychaeta are a Lumbrineridae (genus Lumbricalus) found at both islands and ARs and a bluish Nereididae, found only in the ARs.In the Ascidiacea, a new didemnid has a peculiar zebra-striped pattern (Didemnum sp.1), and which was previously found in the area and the neighbors states of São Paulo and Santa Catarina (R.M. Rocha, unpublished data) and a transparent Eudistoma in small colonies that were usually attached to red coralligenous algae.

Discussion
In this first comprehensive list of the benthic invertebrates on hard substrates of the Currais MPA, many species first records for the state of Paraná.Previous reports of the biodiversity of Currais MPA were superficial and so as a consequence, our field survey increases by 58% the number of species found there.Some of these new records had been found in the neighbor states of São Paulo and Santa Catarina, and so were not surprising.
Most bryozoans have taxonomic issues to be solved before being able to identify species.The unidentified ascidians are new species in the process of being described in our lab.Diplosoma sp., however, will require further sampling in order to identify the species.Some polychaetes are new species, while features to identify some others are lacking.Many sponges are difficult to identify without extensive study of internal anatomy, for which more samples are needed.Thus, 32 taxa remain unidentifiable, which further emphasizes the importance of continued studies in this region.
The differences between taxa found at the islands on natural substrates and those found on artificial substrates were not very surprising.Artificial reefs of concrete to attempt mimicking the natural substrate still have different shapes and textures and they were simply laid on the seabed at           18 m depth.The maximum depth that we surveyed in the rocky shores was 8 m and these differences (light, sedimentation) are likely to explain the differences in species composition.Although similar ecological processes act on different surfaces, communities on artificial substrates are known to be very different from those on adjacent natural substrata (Connell & Glasby 1999, Bulleri & Chapman 2004).However, that being said, these two types of substrate still had 45 species in common.
Two prior studies at the Currais MPA used recruitment plates to evaluate colonization of invertebrates (Brandini & Silva 2011, Bumbeer & Rocha 2012), including time in their survey of species.Those studies found mostly pioneer species, that are likely to be due to propagule supply rather than to the already developed community.This process may also explain the little species overlap between those studies and this (Table 2).Additionally, the former study used plates of the same material as the ARs that were fixed close to the bottom (Brandini & Silva 2011), while the latter used polyethylene plates suspended in the water column (Bumbeer & Rocha 2012).Thus, the studies were different with respect to substrate composition, movement and orientation, and these differences are likely to have caused different suit of species reported in each (Glasby & Connell 2001).
The endangered sea-star Coscinasterias tenuispina is an important species for conservation in Currais MPA (MMA 445/14).In Brazil, this sea-start has a discontinuous distribution, from Bahia to Santa Catarina, and found in Abrolhos (Bahia), Cagarras (Rio de Janeiro) and Arvoredo (Santa Catarina) MPAs, among others.The sea cucumber Isostichopus badionotus (Selenka, 1867) (Figure 4e) was on the Brazilian list of threatened species, but was excluded in the last evaluation (MMA 445/14).This species is classified in the category of least concern by the global IUCN red list, and is abundant in warmer waters of the Caribbean (Toral-Granda et al. 2013).
The remarkable number of new records, and new species, highlights the lack of biodiversity studies in coastal Paraná and many areas of benthic biodiversity on hard substrates remain to be studied, for example, rocky shores bellow depths of 8 m, inventories of cryptic taxonomic groups and vagile benthos other than gastropods, polychaetes and echinoderms.Taxon oriented inventories by specialists are also mandatory for a comprehensive biodiversity survey.For example, a large algal richness was found in a recent study, which found 101 taxa in the Currais Islands (Pellizzari et al. 2014).
The coast of Paraná is in the area of influence of the southern convergence between the cold Malvinas/Falklands current from the south and the warm Brazilian current from the north (Campos et al. 1996, Fernandes & Brandini 2004), and so the communities are expected to include species from both temperate and tropical waters.Coastal Paraná is also the southern range limit for some species, such as the hydrozoan Kirchenpaueria halecioides (Alder, 1859), the polychaete Nicidion cariboea (Grube, 1856) and the sponge Amphimedon sp..It is also the northern range limit for the bivalves Musculus viator (d'Orbigny, 1842) and Brachidontes rodriguezi (d'Orbigny, 1842).Considering the increasing threats to biodiversity, including climate change and ocean warming, that have already caused distributional shifts of species (Sorte et al. 2010), this is an important area to monitor the expansion or constriction of species latitudinal distributions.
Climate change may also modulate the impact and distribution of existing NIS and the establishment of new invasive species (Hellmann et al. 2008).Thus, many NIS found in Currais MPA at low abundances may become invasive, or new species may expand their distribution to Paraná.As has been observed in another MPA located in the southern neighboring state of Coastal Paraná is under the influence of many anthropogenic impacts that favor bioinvasions, such as port-related industries and activities, aquaculture, ships and boat traffic that may contribute to the regional spread of species.Currais MPA is also near freight ship traffic routes as they enter and leave the estuary (Bumbeer andRocha 2012, 2016).As a consequence, the ophiuroid Ophiothela mirabilis was first reported in Paraná in 2000 (Hendler et al. 2012) and has now expanded both its range and abundance and occurs abundantly along the entire coast, including Currais MPA (Figures 2 and 4).This species takes advantage of a variety of hosts (Mantellato et al. 2016), yet we still don't know its impact on the native community.
The only invertebrate taxon oriented inventory at Currais MPA (Rocha & Faria 2005) also provides the opportunity to demonstrate additional changes to community composition.Three of the 12 species found previously but not in this study were probably NIS: the ascidians Aplidium pentatrema (Monniot F., 1972), Eudistoma carolinense Van Name, 1945 and Diplosoma  sp.(Rocha & Faria 2005).Also, the NIS Ascidia tenue Monniot, 1983 was only found on recruitment plates in 2008/2009 (Bumbeer & Rocha 2012).Usually, NIS populations fluctuate widely, so the absence of a few in the present study was not that surprising.We also found some first records for NIS in Currais.The species Didemnum perlucidum was first reported in Brazil (in the São Sebastião Channel) in 1995 (Rocha & Monniot 1995) and found here for the first time for Paraná.This ascidian is now widespread worldwide and a recent study revealed low genetic diversity, including a population from southern Brazil with only one COI haplotype (Dias et al. 2016).This suggests that D. perlucidum is introduced.Botrylloides nigrum Herdman, 1886, another new record for Currais MPA, is considered cryptogenic, but its occurrence on anthropogenic substrates (Rocha & Kremer 2005, Marques et al. 2013) and a new molecular study of global populations (Sheets et al. 2016) suggest that this is also an introduced species in southern Brazil.Symplegma rubra Monniot, 1972 was recorded only within the Paranaguá Estuarine Complex before 2005 (Rocha & Kremer 2005), yet now it is common in Currais MPA.As S. rubra is quite easily encountered and identified, by the large, brightly colored, colonies (Figure 5h), it is unlikely that, if present, it would have passed unnoticed in the 2002/2003 ascidian inventory (Rocha & Faria 2005).Thus, while probably introduced due to its first records in estuarine areas and recent new occurrences, the lack of genetic information on a global scale leads us to call it cryptogenic.
The new records listed emphasize the importance of continuous monitoring for early detection of new introductions, and suggests that protocols should be established for both early response and control of NIS in the management plan of Currais MPA.Biodiversity inventories should also be encouraged and be carried out by taxonomists.Even a simple list of species can provide a baseline after which changes in the ecosystem can be determined by the disappearance or appearance of species, invasion by NIS, and blooms of opportunistic taxa.Here we provide the first step towards understanding the marine ecosystem of the Currais MPA and towards the development of conservation actions in the southern Brazilian coast.

Figure 1 .
Figure 1.The Marine Protected Area of Currais Islands and the sampling sites.Left: the location and area of the MPA in the Paraná coast.Right: detail of the sampling sites inside the MPA.

Table 2 .
List of macroinvertebrate taxa from the sublitoral hard habitats of the Currais Marine Protected Area.Introduced species are indicated in bold type