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INTRODUCTION
Reptiles are among the most threatened ver tebrates worldwide (Todd et al., 2010; Whittaker et al., 2013). Habitat loss and fragmentation, hu man overexploitation, introduced invasive spe cies, emerging diseases, environmental pollution and global warming, severely increase the risk of extinction and population decline of this taxon (Böhm et al., 2016; Bosch et al., 2007; Sinervo et al., 2010). Habitat loss and fragmentation is con sidered to be the leading cause of reptile declines (Gardner et al., 2007).
A key strategy for protecting reptiles’ bio diversity from declining has been the creation and maintenance of protected areas (Chape et al., 2008; Ervin, 2003). Protected areas have long been regarded as an important tool for maintaining habitat integrity and species diver sity (Brooks et al., 2004; Butchart et al., 2010; Rodrigues et al., 2004), covering more than 14.9 % per cent of the planet’s land surface (UNEP-WCMC et al., 2018).
The success of protected areas has gener ally been evaluated using measures in terms of their species diversity, or coverage of endemic and threatened species (Rodrigues et al., 2004), assuming that protected areas provide effective protection once established (Geldmann et al., 2013). Unfortunately, this is not the case of the Auca Mahuida natural protected area.
Regarding the Auca Mahuida natural pro tected area (AM), we highlight that it is an area of great interest for conservation, because is one of the last ones in the country that hold a large number of guanacos (Lama guanicoeMüller, 1776), and harbor some very interesting plant endemisms (Martínez Carretero, 2004). Additionally, it was worldwide renowned sev eral years ago when palaeontologists discovered a high number of dinosaur nests with embryos inside and outside the protected area (Chiappe & Coria, 2004). On the AM, the activities that produce the greatest habitat fragmentation and biodiversity loss are overgrazing and the activi ties related to oil and gas extraction-production. As a result of the land clearance originated for the exploration and exploitation of oil and gas, by the year 2003 the reserve was divided into 793 fragmented habitats with an area of 1.3 km2 each (Fiori & Zalba, 2003).
Reptiles’ inventories can provide material for analyses of biogeographic and phylogenetic patterns and thus provide essential data for deci sion-making regarding the prioritization of areas for biodiversity conservation (e.g., De Oliveira et al., 2014; França & Venâncio, 2010). Here, we provide a checklist of reptiles’ species found along five years of field surveys made within the AM’ current limits.
MATERIALS AND METHODS
Study Area
The AM is located in the Neuquén Province (Argentina), between 37° 30’ - 38 ° 10’ south lati tude and 68° 30’ - 69 ° 15’ west longitude covering 77,000 hectares. This is a Multiple Use Reserve with provincial jurisdiction. The AM is includ ed in the Southern Volcanic Zone of the Andes (SVZ), with a total length of 1,421 km straight. Topographically, the altitudinal ranges vary from 223 m.a.s.l. until 2,258 m.a.s.l., being the high est peak the Auca Mahuida volcano (Martínez & Kutschker, 2011; Völker et al., 2011; Fig. 1).
Fig. 1 Auca Mahuida natural protected area in Neuquén Province, Argentina. Black dots represent the location sampled for reptiles and white dots represent oil wells and mines.
The Monte and Patagónica phytogeographi cal provinces converge on the AM, and com bined with the changing altitude of the terrain and through a time scale, formed distinguishable sectors with a particular and characteristic biota. Therefore, the vegetation becomes typical of the southwestern region of the Monte in the lower slopes and of the Patagonian above 1,200 or 1,500 m.s.n.m. (Long, 2000; Oyarzabal et al., 2018). Intense geological processes of the past, including glaciations and great volcanic activity, changed the relief within Patagonian phytogeo graphical province, thus originating the Payunia district with its own characteristics. These pro cesses created particular ecological conditions that might explain the significant number of endemisms and supports the assessment to con sider Payunia as a high valuable biogeographi cal and speciation area (Martínez Carretero, 2004; Oyarzabal et al., 2018). Within the AM, the Patagonian phytogeographical province is repre sented only by the Payunia district.
In the protected area, the average annual rainfall is 140 - 60 mm (Martínez Carretero, 2004). The hydric deficit of this reserve is the highest of the region (600 mm), and the potential evapotranspiration values range from 700 to 750 mm. The winds are intense and can reach speeds of 80 km/h (Morello et al., 2012).
To compose the list of reptiles’ species in the region, we used data from expeditions conducted from 2007 to 2011 and from the material deposit ed in the herpetological collection LJAMM-CNP of the Instituto Patagónico para el Estudio de los Ecosistemas Continentales (IPEEC-CONICET).
Data collection
We conducted 10 expeditions in spring and summer seasons, comprised in 18 days of field work for the following years: 2007 (February 21th), 2008 (March 7th and 28th; September 26th), 2009 (January 23th; November 14th and 15th; December 4th), 2010 (November 9th to 11th; December 14th and 16th), and 2011 (March 5th and 6th; November 25th to 27th). To conduct field ex plorations, we selected spatial sampling points at different altitudes, according to the access possibilities by roads. At each sampling point, a two-person team did transects runs along repre sentative habitats (each one between 1 to 3 km, usually between 8:30 to 20:00 hs, with a combi nation of visual encounter surveys, road raiding and active search methodology depending on type of habitat, season and climatic conditions), representing at least 220 field hours/person. We selected 42 locations within the AM. We photographed wild animals and for locality confirma tion we used voucher specimens deposited in the LJAMM-CNP collection (Table 1). Also, we use information obtained from original description of endemic species and previous works in the AM.
Table 1 Voucher specimens deposited in the LJAMM-CNP collection, each number is the collection number with geographic coordinates and elevation data.
The effectiveness of the sampling effort was estimated and extrapolated based on rarefaction curves shown as the sample completeness curve, using the R package “iNEXT”. We also used the “iNEXT” package to calculate the effective number of rarefy species for richness (q=0), for Shannon diversity (q=1) and for Simpson diver sity (q=2).
RESULTS
We recorded within AM’ boundaries a total of 16 species of reptiles, 14 species of lizards: Leiosauridae (n=2 spp.), Liolaemidae (n=10 spp.), Phyllodactylidae (n=1 sp.), Teiidae (n=1 sp.), and two species of snakes: Dipsadidae (n=1 sp.) and Viperidae (n=1 sp.; Tab. 1, 2; Fig. 2).
Table 2 Checklist of reptiles with their respective conservation status according to IUCN red list (International Union for Conservation of Nature, 2020): LC (Least Concern), ND (No Data), DD (Data Deficient) and to AHA (Asociación Herpetológica Argentina, 2012): NT (Not Threatened), VU (Vulnerable), ND (No data), IK (Insufficiently Known).
Fig. 2 Species of reptiles from de Auca Mahuida natural protected area in Neuquén Province, Argentina. A, Liolaemus austromendocinus; B, L. crandalli; C, L. cyaneinotatus; D, L. darwinii; E, L. gracilis; F, L. grosseorum; G, L. mapuche; H, L. sitesi; I, Diplolaemus sexcinctus; J, Leiosaurus bellii; K, Phymaturus timi; L, P. sitesi; M, Homonota darwini darwini; N, Aurivela longicauda; O, Philodryas trilineata; P, Bothrops ammodytoides.
Regarding the effectiveness of the sampling effort, the sample completeness curve was close to reach an asymptote (0.98 sample coverage; Fig. 3). The estimated richness showed the pos sible occurrence of 16.5 ± 1.02 species in the area (q=0), indicating that our sample effort was ca pable to detect at least 97 % of the species (n=16). In addition, Shannon (q=1) and Simpson (q=2) diversity index were 12.7 ± 1.01 and 10.6 ± 1.1 respectively.
Fig. 3 Sample completeness curve based on number of individuals of the Auca Mahuida natural protected area. The interpolate curve is represented by a continuous line and the extrapolate curve is represented by a dotted line.
We could observe that the majority of the species fall under the category of Least Concern (IUCN red list) and Not Threatened (AHA) (Table 2). Only two species fall into the category of Vulnerable (AHA), Phymaturus timiHibbard, Nenda & Lobo, 2019 and P. sitesiAvila, Pérez, Perez & Morando, 2011 (Tab. 1).
DISCUSSION
In relation to the completeness of our sam pling, AM was well represented in our surveys. Inside the limits of the AM, the Payunia distric environments (withing the Patagonian phyto geographical province) are essential for the sub sistence of many species, including the genus Phymaturus, declared vulnerable, and with two species cited for this work. Regarding the results of this work, we can highlight the following rep tile species as endemic to the region: Liolaemus crandalli (Avila et al., 2015), L. cyaneinotatus (Martinez et al., 2011), L. sitesi (Avila et al., 2013), Phymaturus sitesi (Avila et al., 2011) and P. timi (Hibbard et al., 2019), indicating that the AM might indeed be isolated for many species (Hibbard et al., 2019) and that makes these envi ronments vulnerable and vital for conservation.
Reviewing previous bibliography of the Monte province, additional species were absent in our sampling: Amphisbaena angustifrons plumbeaGray, 1872 (Montero, 2016), Liolaemus cuy anusCei & Scolaro, 1980 (Medina et al., 2012), L. goetschiMuller & Hellmich, 1938 (Nori et al., 2010), Erythrolamprus sagittifer, (Jan, 1863) (Cei, 1986), Chelonoidis chilensis (Gray, 1870) (Oriozabala et al., 2017) and Salvator rufescens (Gunther, 1871) (Roig et al., 2009). This may be due to the presence of a hard-to-reach canyon, with no available roads at the south-east por tion of the AM, which comprises almost all of the Monte phytogeographical province. For these reasons, the sampled locations were mostly found in the Patagonian phytogeographical province.
Despite having worked with data whose field collections were carried out more than ten years ago, to date no new field works and conservation measures have been implemented in the protect ed area. On the contrary, the anthropic activities within them have been increasing along with the Argentina’s oil drilling boom.
