Animal Biodiversity and Conservation 36.1 (2013) 47 Assessing the extent of occurrence, area of occupancy, territory size, and population size of marsh tapaculo (Scytalopus iraiensis) L. Klemann Jr. & J. S. Vieira Klemann Jr., L. & Vieira, J. S., 2013. Assessing the extent of occurrence, area of occupancy, territory size, and population size of marsh tapaculo (Scytalopus iraiensis). Animal Biodiversity and Conservation, 36.1: 47–57, Doi: https://doi.org/10.32800/abc.2013.36.0047 Abstract Assessing the extent of occurrence, area of occupancy, territory size, and population size of marsh tapaculo (Scytalopus iraiensis).— First described in 1998, the marsh tapaculo (Scytalopus iraiensis) is an endangered bird of the family Rhinocryptidae. It is endemic to Brazil and is restricted to the wet flood plains of rivers and streams. Due to its cryptic habits and environments of occurrence, information available on its biology, natural history and distribution is scarce. We compiled occurrence records (99 records), delimited the extent of occur- rences (296,584 km2), calculated the area of occupancy (84 km2), estimated territory size (5,313 ± 1,201 m2 per pair), population density (3.76 ± 0.85 individuals per hectare), and population size (31,584 ± 7,140 mature individuals) of marsh tapaculo. The species was recorded in marshes associated to four types of vegetation and in four ecological zones. This new information is extremely important to support revaluation of the species’ threat category and to enhance knowledge about this endemic and little known bird from Brazil. Key words: Scytalopus iraiensis, Distribution, Population, Endangered species, Southeastern Brazil. Resumen Evaluación de la extensión de presencia, la superficie de ocupación, el tamaño del territorio y el tamaño de la población del churrín palustre (Scytalopus iraiensis).— Descrito por primera vez en 1998, el churrín palustre (Scytalopus iraiensis) es una ave en peligro de extinción de la familia Rhinocryptidae. Es endémica de Brasil y su presencia queda restringida a los planos aluviales de los ríos y los cursos de agua. Debido a sus hábitos crípticos y a los ambientes en los que se halla presente, la información disponible sobre su biología, su historia natural y su distribución es escasa. Compilamos varios registros de presencia (99 registros), delimitamos la ex- tensión de las presencias (296.584 km2), calculamos la superficie de ocupación (84 km2) y estimamos el tamaño del territorio (5.313 ± 1.201 m2 por pareja), la densidad de la población (3,76 ± 0,85 individuos por hectárea) y el tamaño de la población (31.584 ± 7.140 individuos maduros) del churrín palustre. La especie se registró en zonas de marismas asociada a cuatro tipos de vegetación y en cuatro zonas ecológicas. Esta nueva información es fundamental para respaldar la reevaluación de la categoría de situación de peligro de la especie y potenciar el conocimiento de esta ave endémica y poco conocida de Brasil. Palabras clave: Scytalopus iraiensis, Distribución, Población, Especie en peligro de extinción, Sureste de Brasil. Received: 13 X 12; Conditional acceptance: 18 XII 12; Final acceptance: 8 I 13 Louri Klemann Júnior, Ecology and Conservation Post–Graduation Program, Univ. Federal do Paraná, P. O. Box 19020, Curitiba, Paraná, Brazil.– Juliana S. Vieira, Entomology Post–Graduation Program, Univ. Federal do Paraná, P. O. Box 19020, Curitiba, Paraná, Brazil. Corresponding author: L. Klemann Jr. E–mail: [email protected] ISSN paper: 1578–665 X © 2013 Museu de Ciències Naturals de Barcelona ISSN digital: 2014–928 X 48 Klemann Jr. & Vieira Introduction Material and methods The marsh tapaculo (Scytalopus iraiensis) is a Study area species of the bird family Rhinocryptidae. It was first described in 1998 from specimens taken from The study area included the extent of occurrence of two municipalities in the metropolitan region of Cu- marsh tapaculo, from Rio Grande do Sul (RG), Santa ritiba (capital of Paraná state, southern Brazil) and Catarina (SC) and Paraná state (PR) in Southern its occurrence is known to be restricted to the wet Brazil and São Paulo (SP) and Minas Gerais (MG) flood plains of rivers and streams (Bornschein et state in Southeastern Brazil, between coordinates al., 1998). Its habitat is described as upland mars- 19º 07'–32º 19' S and 43º 20'–52º 28' W. hes and also, at Rio Grande do Sul state (south of Brazil), coastal wetlands associated to grasslands Records and Atlantic Forest biomes (Machado et al., 2005). According to Bornschein et al. (1998, 2001) this Records of the species were obtained from literature, bird occurs in dense humid floodplain watercourses, photos and recordings available on the internet (http:// usually surrounded by alluvial forests, ranging from www.xeno–canto.org/ and http://www.wikiaves.com. less than 1 ha to approximately 350 ha, with a ve- br/), unpublished records from third persons (personal getation height ranging from 60 to 180 cm. communication) and bird surveys carried out by the After the species’ description, new records were first author between 2002 and 2012. For records taken obtained in Paraná, Santa Catarina and Rio Grande from the literature, internet information and personal do Sul states (south of Brazil) and in Minas Gerais communications, the coordinates used were those state (southeast of Brazil) increasing the number provided by the author of each record. When this of locations, municipalities and states with records information was not available and the location could of marsh tapaculo (Bornschein et al., 1998, 2001; not be specified, the municipality centroid was used. Accordi et al., 2003; Maurício, 2005; Straube et al., Due to the species’ cryptic habits (Bornschein et 2005; Bencke et al., 2006; Raposo et al., 2006; al., 2001), the records gathered by the first author Corrêa et al., 2007, 2008; Vasconcelos et al., 2008; were obtained by listening to audio communications Fontana et al., 2008; Rodrigues et al., 2008). Despite stimulated by means of song playbacks. The coordi- the new records, knowledge of this species’ real nates for the points where the species was recorded distribution is still very basic. New records are ex- were obtained through a global positioning system pected even in well–studied regions, an expectation (GPS) device. reinforced by the species’ description fifteen years ago (Bornschein et al., 1998), based on individuals Extent of occurrence, area of occupancy, territory size from a metropolitan region with 1.75 million inhabi- and population size tants (IBGE, 2007), and from records obtained in well–studied locations of Minas Gerais state (e.g. The records were represented in a geographical Serra da Canastra and Serra do Cipó) as of 2003 information system (GIS). The extent of occurrence, (Vasconcelos et al., 2008). defined as the smallest area which can be drawn to The cryptic habits, common to all representatives encompass all the known, inferred or projected sites of this genus, and the flooded environment where of present occurrence of a taxon (IUCN, 2001), was the species occurs make research of this tapaculo delimited by using the minimum convex polygon difficult, accounting thereby for the little information method (Mohr, 1947; IUCN, 2001); this was defined produced and available. To date, only two papers have as the smallest polygon in which none of the internal been published on the species’ biology and behavior angles exceed 180 degrees, and containing all the (Hassdenteufel et al., 2006a, 2006b), and three on the species points of occurrence (IUCN, 2001). This me- species’ distribution (Bornschein et al., 2001; Corrêa thod, usually used to calculate the home range size & Woldan, 2007; Vasconcelos et al., 2008). (Hayne, 1949; White & Garrott, 1990; Harris et al., Apart from the little information available at the time 1990), was adapted to the delineation of the extent of the description, a suggestion was made to include of occurrence (IUCN, 2001). marsh tapaculo in the Brazilian list of endangered By overlaying the records and thematic maps, species (Bornschein et al., 1998, 2001). Nowadays, we identified the vegetal formation (IBGE, 1993) this tapaculo is considered ‘Endangered’ at national and the global ecological zones (ecozones; FRA, and international levels (Machado et al., 2005; BirdLife 2000) where the species occurs. Considering the International, 2012). minimum convex polygon method, which incorpora- This lack of information on biological data and te large areas that are not used or occupied by the distribution details of the marsh tapaculo can lead species (Ostro et al., 1999; Powell, 2000; Burgman to erroneous classification of the threat category. It & Fox, 2003), and aiming to create a realistic extent is therefore extremely important to compile records, of occurrence, this polygon was adjusted using the delimit the extent of occurrence, measure the area of adjusted polygon method (Mills & Gorman, 1987; Li occupancy, and estimate the territory size, population & Rogers, 2005; Grueter et al., 2009) by excluding density and population size in order to reevaluate the vegetal formation without records of the species. the threat category and to expand knowledge of this We also excluded small separated areas, created endemic and little known bird from Brazil. by the polygon adjustment, and great water bodies. Animal Biodiversity and Conservation 36.1 (2013) 49 The area of occupancy, defined as the area inside To measure the territory size, the marsh area the extent of occurrence occupied