(Arachnida: Araneae) Associated with Canopies of Vochysia Divergens (Vochysiaceae) in the Northern Region of the Brazilian Pantanal
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ZOOLOGIA 33(4): e20150170 ISSN 1984-4689 (online) www.scielo.br/zool ECOLOGY Spider assemblage (Arachnida: Araneae) associated with canopies of Vochysia divergens (Vochysiaceae) in the northern region of the Brazilian Pantanal Leandro D. Battirola1*, Daniel A. Batistella1, Germano H. Rosado-Neto2, Antonio D. Brescovit3& Marinêz I. Marques4 1Instituto de Ciências Naturais, Humanas e Sociais, Universidade Federal de Mato Grosso. Avenida Alexandre Ferronato 1200, Setor Industrial, 78557-267 Sinop, MT, Brazil. 2Departamento de Zoologia, Universidade Federal do Paraná. Caixa Postal 19020, 81531-980 Curitiba, PR, Brazil. 3Laboratório Especial de Coleções Zoológicas, Instituto Butantan. Avenida Vital Brasil 1500, Butantã, 05503-900 São Paulo, SP, Brazil. 4Instituto de Biociências, Universidade Federal de Mato Grosso. Avenida Fernando Corrêa da Costa 2367, Boa Esperança, 78060-900 Cuiabá, MT, Brazil. *Corresponding author. E-mail: [email protected] ABSTRACT. This study describes the composition and temporal variation of the spider assemblage (Arachnida: Araneae) associated with canopies of Vochysia divergens Pohl. (Vochysiaceae) in the northern region of the Brazilian Pantanal. Three V. divergens plants were sampled in 2004, at each seasonal period of the northern Pantanal (high water, receding water, dry season and rising water), using thermonebulization of the canopies with insecticide, totaling 396 m2 of sampled canopies. Analysis of abundance and richness of spider families were based on Non-Metric Multidimensional Scaling (NMDS) and Vari- ance Analysis (ANOVA and MANOVA). A total of 7,193 spiders were collected (6,330 immatures; 88.0%; 863 adults, 12.0%) distributed in 30 families. Araneidae (1,676 individuals), Anyphaenidae (1,631 individuals), Salticidae (1,542 individuals) and Pisauridae (906 individuals), were predominant, representing 80.0% of the sample. Ten different guilds were registered: aerial hunters, orb-weavers, nocturnal aerial runners and diurnal space web weavers dominated, sharing most ecological niches. The spider assemblage is affected by changes in the habitat structure, especially by the seasonal hydrological regime and variations in the phenology of V. divergens. The assemblage is composed of different groups of spiders. The dominant taxa and behavioral guilds differ in the different seasonal periods. Spiders were more abundant during the dry and rising water seasons, most likely reflecting a greater supply of potential prey, associated with new foliage and flowering at the canopy. The displacement of soil dwelling spiders to the trunks and canopies before and during the seasonal floods can change the structure and composition of the canopy assemblages. Oonopidae, Gnaphosidae and Caponiidae, were more frequent during the rising and high water seasons, which indicates that these taxa use the canopies of V. divergens as a refuge during the seasonal flooding in the Pantanal. KEY WORDS. Invertebrates, diversity, forest canopy, seasonality, wetlands. Arthropod communities associated with canopies of typical The different composition of spider assemblages most vegetation formations of the northern region of the Pantanal likely reflects the complexity of habitats in the Pantanal. The have been studied in recent years (e.g., MARQUES et al. 2001, 2006, geological and geomorphological history of this biome, together BATTIROLA et al. 2005, 2007, 2014). Spiders, considered the main with its position on the banks of large phytogeographic domains predators of arthropods in most biomes (CARDOSO et al. 2011), are (NUNES-DA-CUNHA & JUNK 1999, 2014), associated with water mentioned in these studies as being important components of seasonality (JUNK et al. 1989), results in a variety of landscapes, these communities, with specific assemblages on each host plant vegetation types (including monodominant forests) and habitats (SANTOS et al. 2003, BATTIROLA et al. 2004, MARQUES et al. 2007, 2011). with specific characteristics (SILVA et al. 2000, NUNES-DA-CUNHA & ZOOLOGIA 33(4): e20150170 | DOI: 10.1590/S1984-4689zool-20150170 | September 5, 2016 1 / 9 L.D. Battirola et al. JUNK 2011). The annual and multi-annual variations in the flood phenology of V. divergens correspond to those presented by pulse affect the biota at different intensities and time scales NUNES-DA-CUNHA et al. (2000) e NUNES-DA-CUNHA & JUNK (2004). (NUNES-DA-CUNHA & JUNK 2004), causing terrestrial organisms to Twelve specimens of V. divergens were nebulized using ther- develop specific strategies to survive and adapt to the strong sea- monebulization of the canopies, three individuals in each seasonal sonality of this floodplain A( DIS et al. 2001, BATTIROLA et al. 2009). period (high water, receding water, dry season and rising water in Among the monodominant vegetation types in the north- 2004). The sampled trees were selected according to the criteria ern region of the Pantanal of Mato Grosso, the “cambarazais” proposed by ADIS et al. (1998), and the methodological procedures are outstanding (SILVA et al. 2000). These are seasonally flooded according to BATTIROLA et al. (2004). The entire diameter at the base forests with dominance of Vochysia divergens Pohl. (Vochysiaceae) of these trees was surrounded by nylon funnels (1 m in diameter (ARIEIRA & NUNES-DA-CUNHA 2006). Vochysia divergens is considered each), distributed according to the shape and architecture of the invasive to native pastures, posing a problem for the local people, canopy, bringing to a total of 396 m2 of assessed canopies (33 m2 who rely on native grasslands for livestock (POTT & POTT 1994, per tree sampled). These collector funnels had a plastic collection NUNES-DA-CUNHA et al. 2000, NUNES-DA-CUNHA & JUNK 2004). While bottle (1 L) at their base with 92% ethanol and were suspended at V. divergens is characterized as a problem for landowners, it is about 1 m from the ground by strings tied to surrounding trees. ecologically important as a habitat and refuge for the wildlife During the high water period the funnels were suspended at 2.5 (POTT & POTT 1994, FASSNACHT 1998, MARQUES et al. 2006), mainly m above the ground due to flooding of the forest (water depth when it is a fully grown tree (NUNES-DA-CUNHA & JUNK 2014). ranging from 0.9 to 1.25 m). The nebulization was applied for 10 The distribution and species richness of predators like minutes using a Swingfog SN50 thermonebulizator, employing spiders may be influenced by the structural conditions of the the non-residual synthetic pyrethroid (Lambdacialotrina at 0.5% host plants even though they do not generally have a direct – Icon®), diluted in diesel oil at a concentration of 1%, associ- relationship with these plants (RAIZER & AMARAL 2001, SOUZA & ated with the synergistic (DDVP 0.1%). This nebulization was MARTINS 2004, 2005, SOUZA & MÓDENA 2004), or by changes in en- performed at around 6:00 am, during less intense air circulation, vironmental conditions (WOLDA 1988). Spiders depend on plant which allows the cloud of insecticide to slowly rise through the structures to attach their webs and to forage. Plant phenology canopy, without dispersion (ADIS et al. 1998). (flowering, fruit development and leaf fall periods), the distri- The collected material was transported to the Laboratório bution of food resources such as the presence of potential prey, de Ecologia e Taxonomia de Artrópodes (LETA) at the Instituto de often represented by herbivorous insects associated with that Biociências, Universidade Federal de Mato Grosso in Cuiabá, MT, host, are also important to these arachnids (COSTELLO & DAANE and subsequently forwarded for identification to the Laboratório 1995, RINALDI & FORTI 1997, SCHAIK et al. 1993, ARANGO et al. 2000). Especial de Coleções Zoológicas, Instituto Butantan, São Paulo, Considering the importance of conservation and man- SP, where it is deposited. The behavioral guilds were determined agement of the specific monodominant forests of V. divergens in according to HÖFER & BRESCOVIT (2001) and DIAS et al. (2010). the Pantanal, as well as the biological diversity associated with Data from the spider assemblage were analyzed using the these habitats, this study analyzed the composition and temporal ordination method by Non-Metric Multidimensional Scaling variation of the spider assemblage in V. divergens canopies. Our (NMDS) for the abundance and presence-absence (qualitative) goal was to evaluate the use of this habitat by spiders over dif- of families (adults + immatures), in order to reduce the dimen- ferent seasonal periods, in the northern region of the Pantanal sionality of information from multiple taxa (CLARKE 1993). The of Mato Grosso, Brazil. dissimilarity between the sampling units was calculated using the associative matrix by means of the Bray-Curtis and Sørensen In- MATERIAL AND METHODS dex. Multivariate Analysis of Variance (MANOVA) was employed using the scores of NMDS dimensions with data of abundance The study area is located at the Retiro Novo Farm, Nossa and presence-absence, and Analysis of Variance (ANOVA) using a Senhora do Livramento, Mato Grosso, Brazil. This area is situated NMDS axes for presence-absence, associated with the a posteriori on the right bank of the Cuiabá River and on the left bank of the Tukey test. These analyses test the existence of average differences Bento Gomes River, Pantanal of Poconé (16°15’24”-17°54’32”S, in the composition of the spider assemblage using categorical 56°36’24”-57°56’23”W) (16°15’12”S, 56°22’12”W). We studied variables (high water, receding water, dry season and rising water). spiders in a monodominant forest of V. divergens, known as They were carried out using the free software R 2.12.1 (R CORE “cambará” whose association is denominated “cambarazal” (NA- TEAM 2013), Vegan package (OKSANEN et al. 2014). SCIMENTO & NUNES-DA-CUNHA 1989). The study area is subjected to a rainy season from October to April and to annual flooding of RESULTS 0.6-1.5 m height, generally between December and March, with four seasonal periods defined as high water (January-March), In 396 m2 of V. divergens canopies, 7,193 spiders from 30 receding water (April-June), dry season (July-September), and families were sampled (18.2 ind./m2).