DOI: 10.5061/dryad.rv15dv4bg
title: Data for: Landscape features affect caiman body condition in the middle Araguaia river floodplain

description: Landscape modifications often undermine habitat suitability for species’
 persistence, with initial effects observed through physiological responses
 of individuals and populations. However, some landscape features can allow
 tolerant wildlife species to persist in human-modified landscapes, but
 they are still overlooked. Across distinct agricultural landscapes, we
 assessed landscape features affecting the body condition (estimate through
 scaled mass index - SMI) of Caiman crocodilus (Crocodylia, Alligatoridae)
 in human-modified landscapes of the Araguaia floodplain, central Brazil.
 We used a spatial Bayesian model averaging approach to determine the
 effects of landscape attributes, ectoparasites, tail damage, and severe
 body injuries on caiman body condition. We found that caimans had higher
 SMI in anthropogenic (ditches and artificial ponds) than natural habitats
 (lakes or rivers). Overall, caiman SMI was negatively associated with
 wetland cohesion (an aggregation and connectivity metric). Otherwise,
 landscape composition did not influence caiman SMI. Further, ectoparasites
 and body injuries did not affect SMI, whereas tail damage negatively
 affected SMI. Our findings underscore that caiman populations can adapt to
 artificial wetlands and irrigated rice fields, provided they incorporate
 natural and semi-natural habitat patches that enhance environmental
 heterogeneity, prey availability, and waterbody availability and
 connectivity.
description: <strong>Study sites</strong> The
 middle Araguaia River floodplain is part of Brazil’s complex and highly
 dynamic Cerrado–Amazonia ecotone (Marques <em>et al</em>.,
 2020a). The annual flood pulse drastically changes the landscape (wet
 season: October–April; dry season: May–September), spanning about 88,000
 km<sup>2</sup> at maximum flood level (February/March) and
 interconnecting several waterbodies, while only 3.3% (2,930
 km<sup>2</sup>) of water area is present in the low-water
 period, September–November (Irion <em>et al</em>., 2016). The
 Araguaia floodplain supports a rich and abundant biota, including many
 endemic and endangered species, protected by a RAMSAR site (Ilha do
 Bananal; no<sup>o</sup>. 624),
 parks, and indigenous lands (RAMSAR, 2002; SEPLAN, 2012).
 We carried out fieldwork between July and September of 2016 and
 2018 (dry season), a period with a higher abundance of caimans in the
 waterbodies (Da Silveira, Magnusson & Thorbjarnarson, 2008;
 Portelinha <em>et al</em>., 2019). We sampled seven localities
 across the middle Araguaia River floodplain: Fazenda Praia Alta, Lagoa da
 Confusão, Tocantins (July 27 – Aug 03, 2016), hereafter Lagoa; Cooperativa
 Agroindustrial Rio Formoso – Cooperformoso, Formoso do Araguaia, Tocantins
 (July 21 – Aug 12, 2018), hereafter Cooperformoso; Cooperativa Mista Rural
 Lagoa Grande – Coopergran, Formoso do Araguaia, Tocantins (July 31 – Aug
 14, 2018), hereafter Coopergran; Fazenda Xavante, Dueré, Tocantins (Aug
 16–23, 2018), hereafter Xavante; Fazenda Bananal-Frutacc, Lagoa da
 Confusão, Tocantins (Aug 25–28, 2018), hereafter Bananal; Centro de
 Pesquisas Canguçu, Pium, Tocantins (Aug 30–31, 2018), hereafter Canguçu;
 Fazenda Santo Antônio, Cristalândia, Tocantins (Sept 02–07, 2018),
 hereafter Cristalândia. The localities were separated from each other by
 at least 20 km to maintain a degree of spatial independence, based on
 migration and movement studies of South American crocodilians that
 indicate maximum movement distances of 20 km in 1–5 years (Gorzula, 1978;
 Ouboter & Nanhoe, 1988; Campos <em>et al</em>.,
 2006). <strong>Study
 design</strong> We sampled natural and
 anthropogenic/artificial habitats in each locality, comprehending 32 sites
 visited in total.  We recorded landscape metrics for
 circular buffers (500-m, 1-km, and 3-km radius) with land use/cover
 rasters from the MapBiomas Project (http://mapbiomas.org, collection 4,
 year: 2016 and 2018). We redefined MapBiomas land-use classes considering
 five categories: water, forest, savanna (savanna, grassland, non-forest
 natural formation, and other non-forest natural formation classes),
 pasture (pasture and other non-vegetated area classes), and agriculture
 (annual and perennial crop class). We excluded the urban class due to low
 coverage representation, less than 1%. To improve water coverage, we
 generated a hydrography raster from a vectorial database acquired from
 Secretaria do Meio Ambiente e Recursos Hídricos of the State of Tocantins
 (https://semarh.to.gov.br/car/base-vetorial-digital-tematica-do-car/).
 Further, we improved MapBiomas land use mapping due to differences between
 supervised <em>in loco</em> coverage and MapBiomas rasters. We
 reclassified and redefined the topology guided by Landsat 8 satellite
 images for the same months of caiman sampling in 2016 and 2018, with a
 30-m pixel spatial resolution obtained from the Instituto Nacional de
 Pesquisas Espaciais–INPE (Brazilian Space Agency; http://www.inpe.br/)
 using QGIS, version 3.12 (QGIS Development Team, 2020).
 For each buffer, we calculated landscape metrics for the
 designated classes with the landscapemetrics package (Hesselbarth
 <em>et al</em>., 2019): the percentage of landscape (PCLASS)
 and mean patch area (MPA) for all classes; the mean Euclidean
 nearest-neighbor distance (ENN), patch cohesion index (COHESION), and
 largest patch index (LPI) restricted to waterbody class; and the landscape
 shape index (LSI) and landscape division index (LDI) (McGarigal &
 Marks, 1995). <strong>Field
 methods</strong> We captured 294 caimans during
 the sampling through nocturnal spotlight surveys with the aid of locking
 cable snares or by hand after locating the animals by eye-reflection
 (Fitzgerald, 2012; Brien & Manolis, 2016). From each captured
 caiman, we recorded the following: habitat type; geographic coordinates,
 with a Garmin GPSMAP 62sc<sup>®</sup>; snout-vent length
 (SVL), from tip of snout to posterior margin of cloaca, and total length
 (TTL), from tip of snout to end of tail, with a 0.1-cm precision tape;
 body mass, with a 0.1-kg precision spring scale; and sex, by cloacal
 examination and palpation of the penis. Moreover, we recorded the presence
 of ectoparasites (ticks and leeches) and severe injuries (amputations,
 lesions, fractures, and lacerations) in the animals. We conducted this
 study under permits SISBIO #13324-6 and #57940-3 (issued by Instituto
 Chico Mendes de Conservação da Biodiversidade), FUNAI
 #08620.005147/2018-38 (Fundação Nacional do Índio), and CEUA-UnB #94/2017
 (Comissão de Ética no Uso de Animais da Universidade de
 Brasília). We used the SVL as a body size estimate
 instead of total length due to bias resulting from tail loss and damage.
 We estimated the body condition of <em>Caiman crocodilus</em>
 using the scaled mass index – SMI (Peig & Green, 2009).
description: Programs able to use: Excel and R plataform.