Brazil is a megadiverse country, including six biomes (Ab’Sáber 2003). One of its most distinguishable regions is the complex of ecotones adjacent to the Amazon forest of northern Brazil, the Caatinga in the northeastern portion of the country, and the Cerrado of central Brazil (Ab’Sáber 2003; Olson et al. 2005, Rodrigues 2005). In the very heart of this transitional region, one of the most remarkable environments is a region known as Lençóis Maranhenses in the state of Maranhão, located in the northeast of Brazil. The Lençóis Maranhenses comprises an unexpected and admirable landscape composed of the largest dunefields in Brazil (about 120, 000 ha of continuous sand dunes), which is scattered by thousands of freshwater lagoons formed annually by rainfalls. In 1981, the area was converted into a park called Lençóis Maranhenses National Park due to its amazing scenery. Despite its relevance as a unique ecosystem in that transitional zone, animal and plant components are still poorly known. The few available studies just focused on individual species, usually only reporting its occurrence (e. g. Rêgo and Albuquerque 2006). There is no published inventory of the flora and fauna of Lençóis Maranhenses National Park. Regarding the fauna of reptiles in the park, the only study we are aware of is a description of a new turtle species by (Vanzolini 1995). The lack of a species list restricts the knowledge of the reptile species composition in the area. This hampers specific conservation efforts to protect local species diversity. Herein, as a result of almost two years of study conducted in the area, we are providing a report of reptile species composition for the Lençóis Maranhenses National Park, a detailed description of the main mesohabitats in the area, and some suggestions to improve the conservation of reptiles in the park.

We recorded 42 reptile species in the LMNP: 12 species of lizards, belonging to 11 genera and eight families (Gekkonidae, Sphaerodactylidae, Mabuyidae, Gymnophthalmidae, Iguanidae, Polychrotidae, Teiidae and Tropiduridae); two species of worm lizards belonging to the genus Amphisbaena, in the family Amphisbaenidae; 24 species of snakes, belonging to 20 genera and four families (Boidae, Colubridae, Dipsadidae and Elapidae); three species of turtles, belonging to three genera and three families (Cheloniidae, Dermochelyidae, and Emydidae); and one species of alligator (Alligatoridae) (Table 1).

The species-accumulation curves for snakes and lizards have different slopes and confidence intervals according to the reptile group studied. Nevertheless, both curves predicted more species than currently recorded. Richness for each reptile group was quite close to the predicted values, especially for the lizards (Figures 3 and 4). The first order Jackknife estimator predicted that 13 to 15 species of lizards [N(J1) = 13, 99 ± 1, 40], and 28 to 34 species of snakes [N(J1) = 30, 97 ± 2, 95] might be recorded in LMNP. Overall, most reptile species that we recorded at LMNP were found in the restingas (Table 1).

In the management plans of the LMNP, there is no list of Herpetofauna’s species (Castro and Piorski 2002). However, there is mention about the occurrence of the Brazilian slider turtle, Trachemys adiutrix, in the park. Thus, our study added 41 species to the number of reptiles known in the LMNP. Despite the uniqueness of the environment, and conditions in the LMNP, the reptile taxocenosis recorded there includes species normally found in the biomes that surround it. For instance, Gonatodes humeralis and Varzea bistriata which are associated with the Amazon, and Philodryas nattereri, Polychrus acutirostris and Brasiliscincus heathi which are typical Cerrado and Caatinga inhabitants. One remarkable exception is Trachemys adiutrix, which is endemic to a small area at the coast of Maranhão and Piauí (see Ávila-Pires 1995, Rodrigues and Prudente 2011, Mesquita et al. 2006, Vanzolini 1995 and references therein). Therefore, LMNP has a significant importance for conservation of reptiles in Brazil, as it includes in one relatively small area (155, 000 ha), a single taxocenosis of reptiles that combine species from various Brazilian biomes, all in a very unique landscape.

In LMNP there are only three species of lizards: (Tropidurus hispidus, Ameivula ocellifera, and Tupinambis teguixin), one snake (Erythrolamprus poecilogyrus), and Trachemys adiutrix which were recorded in sand dune areas. Additionally, two sea turtles were recorded at the coastal area of the park (Chelonia mydas and Dermochelys coriacea). Thus, about 81 % (34 species) of reptile species recorded at LMNP were only found in restingas. In addition, the management plans of the LMNP emphasize the innermost isolated restingas for their actions in conservation, as opposed to restinga areas located at the southern LMNP (Castro and Piorski 2002). The importance of actions to protect the innermost isolated restingas is justified due to the high diversity of plant species found in those isolated areas (Castro and Piorski 2002). However, the reptile taxocenosis from the park did not follow that pattern of richness. The species recorded at the isolated restingas were only a subset of the reptile species registered at the restingas which are adjacent to sand dunes in the southern LMNP (see Table 1 and Figure 2).

During our field work, we observed that the restingas in the south area of the park (both inside the park and in the buffer zones) have been strongly disturbed by the clandestine openings of paths created to transport tourists to the dunes and lagoons in the park, using off-road vehicles. This problem is more severe during the rainy season (from January from June) when paths become muddy quickly, and new paths are continuously opening. Restinga are extremely sensitive to clearing because the poor soils hinder habitat recomposition (Hay et al. 1981). In fact, the restinga areas in the south of the park (outside LMNP) are included in an environmental protection area called APA Upaon Açu-Miritiba-Alto Preguiças, which is a type of protected area in the Brazilian system of conservation units which ensures sustainable use. However, the surveillance of this use is still very limited.

On the beach and sand dune areas, we recorded three species of turtles which are included in the IUCN Red List of Threatened Species (IUCN 2012): Dermochelys coriacea (critically endangered), Chelonia mydas (endangered), and Trachemys adiutrix (endangered). During our field work, we observed the Trachemys adiutrix (locally called “Pininga”) being used as a food source; eaten by the extremely poor human population which live in the park area and surroundings. These turtles cannot be seen very easily in LMNP during most of the year. However, as the lagoons begin to diminish (both in number and surface) in the dry season, these turtles concentrate in the few remaining lagoons, making it easy to capture a large number of individuals at the same time. Some people capture the turtles and keep them alive, in order to eat them during the dry season. This is the time when fish and other food items are scarce for the local human population.

In the sand dunes at LMNP, which is an extremely open area, the ground temperature can easily exceed 70° C during the warmest period of the day (JPM Pers. Obs.). This particular characteristic of sand dune areas reinforces the importance of shelters (dead branches and patches of vegetation) and burrows for the species that live there. For lizards, shelters and burrows are important for thermoregulation, as this is one of the few options to decrease exposure to the sun (Rocha et al. 2009). Furthermore, in sand dune areas at LMNP, there are some species of predatory birds like “carcará” (Polyborus plancus, Falconidae) and “caburé” (Athene cunicularia, Strigidae) (JPM Pers. Obs), known to prey on reptiles (Andrade et al. 2010, Vargas et al. 2007). Thus, shelters and burrows may also be important for the protection against predators. Whiptail lizards (Ameivula ocellifera) have a great ability to dig (see Eifler and Eifler 1998), which might have been important for their successful establishment in sand dunes. The other lizard species found in sand dunes, Tropidurus hispidus, is not able to dig as well, but is known as a species with great flexibility in habitat use (Ávila-Pires 1995). In sand dunes at LMNP, Trachemys hispidus is often sheltered in dead branches of the shrubs buried by sand. During our fieldwork, we often observed the clandestine traffic of off-road vehicles in the dunes, which can be harmful to the reptiles that live in that mesohabitat due to the fact that heavy vehicles destroy a large number of burrows and shelters used by those species. This would be similar to the adverse effects of off-road vehicles on lizard populations observed by Busack and Bury (1974) in the Mojave desert, USA.

The only exotic invasive reptile species at LMNP was the gecko Hemidactylus mabouia, which was found on different occasions in natural habitats and microhabitats within the study area. This lizard, which is native from Africa, is one of the five invasive reptile species presently known to occur in Brazil (Rocha et al. 2011) and has continuously invaded natural environments in Brazil during the past 70 years (Rocha et al. in press).

Our data highlight the singularity of the LMNP in the context of the biomes that surround it, and also demonstrate the importance of actions to improve conservation of reptiles that live in both sand dunes and restingas in LMNP. Currently, restingas comprise only about 20% of the total area protected by the park, but most reptile species live in restinga mesohabitats. Thus, we suggest the addition of restinga areas adjacent to the park (buffer zones) to be incorporated into the national park, which is a fully protected conservation unit in the Brazilian system of conservation units. This would be the most effective way to protect the biodiversity of reptiles in the restinga areas in that region. Moreover, regarding the sand dunes areas; we suggest an improvement in the security at the LMNP to prevent the illegal use of off-road vehicles inside the park territory, the promotion of actions to monitor the activities of sea turtles at the coast of LMNP, and the implementation of an effective strategy to protect the Brazilian slider turtle. This strategy could be in the form of awareness campaigns, or even the promotion of training courses (e. g. tourist guides, waiters, cooks, or hotel maids) for those living in the park region. This would place local people into the tourism business, which would not only improve their economical capacity, but also reduce their need to use Trachemys adiutrix as a food item.