bonaldo y dias, 2010

7/28/2019 Bonaldo y Dias, 2010

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357 VOL. 40(2) 2010: 357 - 372

A structured inventory o spiders (Arachnida,

Araneae) in natural and artifcial orest gaps at PortoUrucu, Western Brazilian Amazonia

Alexandre B. BONALDO , Sidclay C. DIAS2

ABSTRACT

A preliminary survey o the spider auna in natural and articial orest gap ormations at Porto Urucu, a petroleum/natural gasproduction acility in the Urucu river basin, Coari, Amazonas, Brazil is presented. Sampling was conducted both occasionally andusing a protocol composed o a suite o techniques: beating trays (32 samples), nocturnal manual samplings (48), sweeping nets(), Winkler extractors (24), and pitall traps (20). A total o 420 spiders, belonging to 43 amilies and 33 morphospecies,

were collected during the dry season, in July, 2003. Excluding the occasional samples, the observed richness was 357 species. Ina perormance test o seven species richness estimators, the Incidence Based Coverage Estimator (ICE) was the best t estimator,

with 3 estimated species. o evaluate dierences in species richness associated with natural and articial gaps, samples rombetween the center o the gaps up to 300 meters inside the adjacent orest matrix were compared through the inspection o thecondence intervals o individual-based rareaction curves or each treatment. Te observed species richness was signicantly higherin natural gaps combined with adjacent orest than in the articial gaps combined with adjacent orest. Moreover, a communitysimilarity analysis between the auna collected under both treatments demonstrated that there were considerable dierencesin species composition. Te signicantly higher abundance o Lycosidae in articial gap orest is explained by the presence oherbaceous vegetation in the gaps themselves. Ctenidae was signicantly more abundant in the natural gap orest, probable dueto the increase o shelter availability provided by the allen trees in the gaps themselves. Both amilies are identied as potentialindicators o environmental change related to the establishment or recovery o articial gaps in the study area.

KEYWORDS: spider inventories, richness estimators, orest gaps, Brazilian Amazonia.

Inventrio estruturado de aranhas (Arachnida, Araneae) em clareirasnaturais e artifciais em Porto Urucu, Amaznia Ocidental Brasileira

RESUMO

Apresenta-se um inventrio preliminar da auna de aranhas em clareiras naturais e articiais em Porto Urucu, uma instalaoprodutora de petrleo e gs natural na bacia do Rio Urucu, Coari, Amazonas, Brasil. As amostras oram realizadas de modo ocasionale com um protocolo estruturado composto por um conjunto de tcnicas de amostragem: guarda-chuvas entomolgicos (32 amostras),amostras manuais noturnas (48), rede de varredura (), extratores de Winkler (24) e armadilhas de queda (20). Um total de 420aranhas pertencentes a 43 amlias e 33 moroespcies oi coletado durante a estao seca em julho de 2003. Excluindo as amostrasocasionais, a riqueza observada oi de 357 espcies. No teste de desempenho de sete estimadores, ICE (Incidence Based CoverageEstimator) gerou o melhor resultado, com 3 espcies estimadas. Para avaliar dierenas na riqueza de espcies associadas a clareirasnaturais e articiais, conjuntos de amostras do centro da clareira a at 300 m adentro da foresta adjacente oram comparados atravs da

inspeo dos intervalos de conana de curvas de rareao baseadas no nmero de indivduos de cada tratamento. A riqueza observadaoi signicantemente maior nas clareiras naturais combinadas com as forestas adjacentes do que nas clareiras articiais combinadascom as matas do entorno. Alm disso, uma anlise de similaridade entre as aunas coletadas em ambos os tratamentos mostrou queexiste dierenas considerveis na composio de espcies. A abundncia signicativamente mais alta de Lycosidae nas forestas declareiras articiais explicada pela presena de vegetao herbcea nas clareiras propriamente ditas. Ctenidae oi signicantementemais abundante nas forestas de clareiras naturais, provavelmente devido ao aumento da disponibilidade de abrigos causado pelaqueda de rvores nas clareiras propriamente ditas. Ambas estas amlias so identicadas como potenciais indicadores de mudanasambientais relacionadas com o estabelecimento ou recuperao de clareiras articiais na rea de estudo.

PALAVRAS-CHAVE: inventrios de aranhas, estimadores de riqueza, clareiras, Amaznia Brasileira.

1 Museu Paraense Emlio Goeldi, E-mail: [email protected] Museu Paraense Emlio Goeldi, E-mail: [email protected]


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A structured inventory of spiders (Arachnida, Araneae) in natural andartificial forest gaps at Porto Urucu, Western Brazilian Amazonia

INTRODUCTION

Structured inventories o spider communities have

been implemented on a regular basis in Amazon Basin onlyrecently (Silva, 2, ). Despite the act that severalsuch initiatives have been conducted in Brazilian Amazoniaduring the last 0 years, only two papers dealing with spidercommunity structure have been published so ar. Borges &Brescovit () provided data rom two western Amazonianlocalities, Te Reserva de Desenvolvimento SustentadoMamirau and Boca do Sumama, both near e, Stateo Amazonas. Her & Brescovit (200) presented results o along term spider inventory carried out at the Reserva Florestal

Adolo Ducke (RFAD), Manaus, Amazonas.

Porto Urucu, the locality addressed in this paper, is

practically unknown regarding the composition o its spidercommunities. Only six spider species rom that area wererecorded in the literature so ar. Te Ctenids Centroctenusauberti(Caporiacco), Ctenus inajaHoer, Brescovit & Gasnier,Ctenus villasboasiMello-Leito, Cupiennius celerrimusSimonandAncylometes ruus(Walckenaer) were reported by Brescovit(), Her et al. (4), Brescovit & Eickstedt (5) andHer & Brescovit (2000). A single species has Porto Urucuas its type locality, Rhoicinus urucu (rechaleidae), describedby Brescovit & Oliveira (4) on specimens collectedoccasionally in bromeliads during a foristic and herpetologicalinventory carried out in early 0s.

Te study area is located nearly 00 kilometers southwestManaus and harbors an oil/gas exploitation acility establishedin the 80s. One o the most conspicuous results o thisintervention is the creation o deorestation gaps in thedry land orest matrix to allow activities related to probing,establishing and operating petroleum and gas wells. Tese gapsare opened or several specic purposes, such as helicopterlanding, drilling o wells and assembling o equipment oroil/gas extraction and transerring. One o the most commonkinds o articial gaps in Porto Urucu is the so called Jazidas(here termed JAZ gaps), represented by the gaps assignedor the aerial deposit o soil and raw materials or highwayconstruction, typically located near the margins o the roads.

Tese clear-cut, soil-compacted areas are probably the mostdistinct articial gaps in the study area.

In order to access the spider assemblages in both naturaland articial orest gaps, as well as in the dry land orest matrixadjacent to those gaps, we compared a set o high impacted

JAZ gaps, each one rom ve to seven years in age, and aset o natural orest gaps, ormed by the natural all o oldtrees. Tis paper reports a rst attempt to describe the spidercommunities under these novel environmental conditionsand provides the ollowing preliminary data on the Urucuspider community structure as well as on the impact o oil/gas exploitation activities in the spider auna o the study area:

() a general checklist, including data on species compositionobtained both occasionally and using a structured inventory;(2) a characterization o the dierences in species richnessand composition o the spider auna present in both articialand natural orest gaps ormations; (3) comparisons betweenthe perormance o several richness species estimators and;(4) suggestions o appropriate environmental indicator taxaor both establishment and recovery o articial gaps in thestudy area.

MATERIAL AND METHODS

STUDY AREA

Porto Urucu is a 54000 ha petroleum/natural gasproduction unity in the right margin o Urucu River, Solimes

river basin, State o Amazonas, Brazil (4 53S, 5 20W).Regional climate is classied as A by the Kppen system,

with the rainy season between September and April, and thedry season between May and August (RADAM-BRASIL,78). Te main orest ormation in Porto Urucu is terrarme (dry land) associated with lowlands and plateaus asdescribed by Ribeiro et al. () and cut by small creeks(Igaraps), tributaries o the Urucu River. Tree main creeksare located in the study area (Lontra, artaruga and Martacreeks). Natural gaps are ormations produced in the orestmatrix rom allen trees or large branches rom the canopy,exposing the orest ground to direct solar radiation. Te

natural orest gaps sampled were coded as NA (04 57.7S, 5 044.4W), NA2 (04 522.5 S, 5 04.2W),NA3 (04 535.8 S 5 04 .7W) and NA (045342S, 5 8W). All articial orest gaps sampled

were originated rom the construction or maintenance o thePorto Urucu road network, named JAZ (04 5207S,5 553W), JAZ 40 (04 523S, 5 005W), JAZ4 (04 5304S, 5 02W) and JAZ 55 (04 433S,5 050W).

COLLECTING

he data presented here were obtained in a single

expedition carried out in July, 2003. Five methods were usedto access the spider auna; pitall traps, Winkler extractors,beating trays, sweep-net and nocturnal hand searches, during3 days by three collectors. Te samples were obtained romboth the center and the edge o a given orest gap, as well asinside the orest immediately associated with the gap, until300 meters rom gap edge. Te edge o a given orest gap wasroughly dened as a ten meters wide band circling the gap.Sweeping was perormed only in the center o each orestgap and the nocturnal hand search was not applied in thegap edges. Tere was a total o 20 pitall trap samples (0in the natural orests gap and 0 in the articial orests gap),


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24 Winkler extractor samples (three by area), 32 beating traysamples, samples o sweep-net and 48 samples o nocturnalcollections, were obtained. Pitall traps were used to accessthe litter-dwelling spiders. Each trap, composed o a 500 mlplastic cup o 0cm diameter buried to the level o the soil,

was placed at least 5 meters apart one rom another. Alcohol(80 proo) was used as the preserving liquid.

EstimateS sotware 7.5 (Colwell, 200). Dierences in speciesrichness in both JAZ and NA communities (dened asthose under the infuence o either articial or naturals orestgaps) were visualized through the inspection o the 5%condence intervals o individual-based rareaction curvescalculated using EcoSim 7 (Gotelli & Entsminger, 200).Kulczynskis (sensu oti et al., 2000) and Srensens index osimilarity were used to compare the composition o speciesin the two communities (Wolda, 8; Krebs, ). otest the normality o the abundance data o Ctenidae andLycosidae using the total sum o individuals (juveniles andadults) present in each JAZ and NA samples, the Lillieorstest was implemented in BioEstat 4.0 (Ayres et al., 2005). Asthe Ctenidae data set was homocedastic and the Lycosidae one

was heterocedastic, Students test and Mann-Whitney tests

were used respectively, also through BioEstat 4.0, to veriy thedierences in abundance o these amilies in both articialand natural gap orests.

RESULTS AND DISCUSSIONS

ASSEMBLAGE COMPOSITION

Te samples obtained in Porto Urucu rom both natural andarticial orest gaps, together with those obtained occasionally inthe vicinities o the Lontra and artaruga creeks, produced 420spiders, belonging to 43 amilies. Te most abundant amily wasCtenidae, with 74 specimens, ollowed by Araneidae, Lycosidae,

Teridiidae and Salticidae, each one accounting or between400 to 500 individuals. Tese ve amilies represented 58.3%o all spiders collected. Seven amilies were recorded by onlyone specimen (Clubionidae, Dictynidae, Hahniidae, Idiopidae,Nephilidae, Paratropididae and etrablemmidae) and three wererepresented by two specimens each (Cyrtaucheniidae, Hersiliidaeand Palpimanidae) (see Fig. or data on abundance per amily).

MethodGap Edge

Adjacentforest Total

NAT JAZ NAT JAZ NAT JAZ

Pitfall-trap 20 20 20 20 20 20 120

Winkler extractor 4 4 4 4 4 4 24

Beating tray - - 4 4 12 12 32

Sweep-net 8 8 - - - - 16

Nocturnal handsearch

12 12 - - 12 12 48

Total 44 44 28 28 48 48 240

Table 1 - Sampling design applied to the structured inventory of spiders innatural and artificial forest gap areas in Porto Urucu, Coari, Amazonas, Brazil.

Beating trays were used to access shrub-dwelling spidersduring the day. Each beating tray was comprised o a 0,80m2

cotton white sheet. Nocturnal hand searches were modiedrom the looking up looking down method proposed byCoddington et al. (). More detailed descriptions o these

methods are avaliable in Coddington et al. () and Brescovitetal.(2002, 2004). Te samples combined across each methodologywere the results o: one pitall trap exposed by 0 days, one squaremeter litter (sited and included in Winkler extractors or 3 days),one hour o beating per collector, one hour o sweeping percollector and, one hour o nocturnal hand search per collector,inside an area o 300m2. o improve the taxonomic list o thestudy area, we also perormed occasional samplings in the marginso the Lontra and artaruga creeks. Tese occasional samplings

were carried out using time-independent oliage beating duringthe day and time and area-ree hand searching at night. Voucherspecimens were deposited in the arachnological collections oMuseu Paraense Emlio Goeldi, Belm (MPEG).

STATISTICAL PROCEDURES

Sample intensity (SI) was dened as the ratio o adultsto species (Coddington et al., ). Seven non-parametricestimators o species richness (Chao , 2, Jackknie , 2,Bootstrap, ACE and ICE) were used in order to veriy whichrichness estimators t best to the present data set. Detaileddescriptions o these algorithms are available in Colwell &Coddington (4), oti et al. (2000) and Colwell (200). oreduce the infuence o the sample order, 00 randomizationso sample sequence were made or each sample increment(Coddington et al. ). Tis analysis was perormed using

Figure 1 - Number of individualsperfamily collected in Porto Urucu, Coari,Amazonas, Brazil. Families with less than 20 individuals were grouped asothers.


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Considering only the adult spiders collected, the numbero amilies represented in the samples decreases to 37, asIdiopidae, Paratropididae, etrablemmidae (represented bysingletons), Cyrtaucheniidae (two individuals), Gnaphosidae(ive) and Zodariidae () were represented only byunidentiable juveniles. Te observed richness was 33 speciesor morphospecies, represented by 2 adults (38.3% oall spiders collected). From all the recognized species, only47 were identied to species level, highlighting the poortaxonomic knowledge o the Western Brazilian Amazoniaspiders. Only our o these species were previously reported tooccur in Porto Urucu. wo remaining species reported to thestudy area in the taxonomic literature, Cupiennius celerrimusand Rhoicinus urucu, were not re-collected.

Te sampling intensity was only our individuals per

species, a low value when compared with the gures obtainedin structured inventories in North America (e.g. Coddingtonet al., , Appalachian Mountains, SI = 8.3) and Europe(e.g. Scharet al., 2003, Denmark, SI = 32). However, lowsampling intensity values are common in inventories carriedout in tropical sites, such as those reported by Coddington etal. () (Bolivia, three localities, SI < 5), and even in some

sub-tropical sites, as reported by Bonaldo et al. (2007) (Stateo Rio Grande do Sul, Brazil; SI = 0.4, but infated by theinclusion o identiable juveniles in the calculation; SI = 8.8,excluding the identiable juveniles and ew species identiedonly by juveniles). Te number o species represented bysingletons was 7. Tus, the inventory completeness, denedby Coddington et al. () as the percentage o speciesrepresented by singletons, is still high (42.5% o all recognizedspecies). Tis is another indication that this preliminaryinventory is ar rom complete.

In terms o number o species, the richer amilies wereTeridiidae (8 spp.), Salticidae (0 spp.) and Araneidae (57spp.), conrming the general pattern observed in Neotropicalecosystems (Silva, 2). able 2 depicts the species andmorphospecies recorded in Porto Urucu, with the number o

individuals collected by sampled area. Te occasional samplingin the Igaraps Marta and artaruga added 3 species to thelist, mainly representatives o Pholcidae and rechaleidae. Atleast some o these species are characteristically ound near

water, as in the case o several rechaleidae and some Pisauridae(Her & Brescovit, 200).

Species/Areas N 1 N 2 N 3 N 9 J 19 J 40 J 46 J 55 IGL IGT TOTAL

Anapidae

Gen. sp. 1 5 1 1 7Gen. sp. 2 2 2 4

Gen. sp. 3 4 2 1 7

Gen. sp. 4 1 1

Anapisona sp. 1 2 1 3

Anyphaenidae

Gen. sp. 1 1 1

Araneidae

Gen. sp. 1 1 1

Gen. sp. 2 2 2

Gen. sp. 3 2 2

Gen. sp. 4 1 1 2

Acacesia sp. 1 1 1 1 3Alpaida aff.antonio 4 1 1 2 8

Alpaida bicornuta 1 1

Alpaida delicata 1 6 8 4 8 3 2 32

Alpaida leucogramma 4 1 1 2 8

Alpaida sp. 1 2 1 3 5 1 2 14

Alpaida sp. 2 1 1

Alpaida sp. 3 1 1 2

Alpaida sp. 4 1 1

Alpaida sp. 5 2 2

Alpaida sp. 6 4 4

Table 2 - List of spider species and morphospecies recorded from Porto Urucu, Coari, Amazonas, Brazil, with the number of adults collected in each samplingsite. NAT, natural gaps; JAZ, artificial gaps; IGL, Igarap (creek) Lontra; IGT, Igarap (creek) Tartaruga.


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Alpaida sp. 7 1 1

Alpaida sp. 8 1 1

Alpaida sp. 9 1 1

Alpaida sp. 10 1 1

Alpaida sp. 11 1 1 2

Alpaida sp. 12 1 1

Argiope argentata 6 6

Aspidolasius sp. 1 1 1

Azilia sp. 1 1 1

Chaetacis aureola 1 1 2

Cyclosa fililineata 1 1 2

Cyclosa longicauda 1 1

Eustala sp. 1 1 2 2 2 1 8Eustala sp. 2 1 1 1 2 5

Eustala sp. 3 1 1 2

Eustala sp. 4 1 1

Eustala sp. 5 1 1

Eustala sp. 6 1 1 2

Eustala sp. 7 2 1 1 4

Eustala sp. 8 1 1

Hypognatha sp. 1 3 1 1 5

Kapogea sexnotata 1 1

Mangora sp. 1 4 1 3 1 1 1 2 13

Mangora sp. 2 1 1 1 3



Mangora sp. 5 1 1 2

Mangora sp. 6 1 2 3

Metazygia sp. 1 1 1 1 3

Metazygia sp. 2 1 1 2

Micratena aff.lata 1 1

Micratenaclipeata 1 1 1 3

Micratena triangularispinosa 1 3 4

Micratena pungens 1 1 2

Ocrepeira sp. 1 1 1 2

Parawixia kochi 1 1 1 1 4

Parawixia tarapoa 1 1

Spilasma duodecinguttata 1 1 2

Wagneriana lechoza 1 1 2

Wagneriana silvae 1 3 4

Wagneriana undecimtuberculata 2 1 3

Wagneriana sp. 1 1 1 2

Caponiidae

Nops sp. 1 1 1

Clubionidae

Elaversp. 1 1 1

Table 2 - Continuao


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Corinnidae

Abapeba taruma 1 1 2

Castianeira sp. 1 1 1

Castianeira sp. 2 1 1 2

Corinna aff.kochisp. n. 1 1 1

Corinna aff. recurva sp. n. 1 2 1 4 7

Corinna aff.recurva sp. n. 2 1 1 2

Corinna aff. ducke sp. n. 1 1 1 1 3

Corinna sp. 1 1 1 2

Corinna sp. 2 1 1

Creugas sp. 1 1 1

Falconina sp. 1 1 1

Methesis sp. 1 1 1Myrmecium sp. 1 3 1 1 2 2 1 2 4 16

Myrmecium sp. 2 1 1

Myrmecium sp. 3 1 1

Parachemmis sp. n. 1 1 1

Simonestus sp. n. 1 2 2 4

Sphecotypus sp. 1 1 1

Stethorrhagus lupulus 1 1 2

Trachelas sp. 1 1 1 2

Trachelas sp. 2 3 1 4

Trachelas sp. 3 1 1

Trachelas sp. 4 1 1

Ctenidae

Ancylometes amazonicus 1 1

Ancylometes rufus 4 2 1 3 1 2 3 5 3 24

Ancylometes sp. 1 1 1

Centroctenus auberti 1 1

Centroctenus sp. 1 2 2 3 1 1 1 10

Centroctenus sp. 2 5 1 1 1 8

Centroctenus sp. 3 2 2

Ctenus amphora 2 6 8

Ctenus crulsi 4 2 6 3 4 2 4 2 1 28

Ctenus inaja 1 1 2

Ctnenus minor 2 2Ctenus sp. 1 1 1 2 4

Ctenus sp. 2 2 2 2 1 1 2 5 7 4 26

Ctenus sp. 3 1 1 1 1 1 2 7

Ctenus sp. 4 1 1

Ctenus sp. 5 1 1

Ctenus aff. villasboasisp.1 1 1 2

Ctenus villasboasi 1 1 1 3

Cupiennius celerrimus 2 1 3 4 1 3 1 4 7 26

Enoploctenus mapia 1 2 1 4

Gephyroctenus sp. 1 1 1

Gephyroctenus sp. 2 2 4 1 7

Table 2 - Continuao


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Gephyroctenus sp. 3 1 1

Phoneutria fera 1 1 1 3

Phoneutria reidyi 1 2 3

Deinopidae

Deinops sp. 1 1 1 2 1 5

Dictynidae

Dictynidae sp. 1 1 1

Dipluridae

Diplura sp. 1 1 1

Hahniidae

Gen. sp. 1 1 1

Hersiliidae

Ypypuera crucifera 1 1 2Linyphiidae

Gen. sp. 1 1 5 6

Gen. sp. 2 1 1 2

Gen. sp. 3 1 1

Gen. sp. 4 1 1

Gen. sp. 5 1 1

Gen. sp. 6 1 1

Dubiaranea sp. 1 5 2 12 12 3 1 35

Dubiaranea sp. 2 1 2 3

Dubiaranea sp. 3 1 1

Meioneta sp. 1 1 1

Sphecozone sp. 1 1 1

Sphecozone sp. 2 3 6 5 2 16


Sphecozone sp. 4 2 1 1 4



Lycosidae

Aglaoctenus castaneus 1 1

Gen. sp. 1 7 17 27 64 8 123

Gen. sp. 2 6 1 2 1 10

Gen. sp. 3 1 1

Mimetidae

Ero sp. 1 1 1 2 1 5

Ero sp. 2 1 1

Ero sp. 3 1 1

Ero sp. 4 2 2

Mimetus sp. 1 1 1

Mimetus sp. 2 1 1

Mimetus sp. 3 1 1 2

Mysmenidae

Gen. sp. 1 2 3 10 1 16

Gen. sp. 2 4 4

Table 2 - Continuao


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Miturgidae

Teminius insularis 3 1 4

Nephilidae

Nephila clavipes 1 1

Ochyroceratidae

Gen. sp. 1 1 1 2

Gen. sp. 2 4 2 3 5 2 3 1 20

Gen. sp. 3 6 7 17 8 2 4 4 1 49

Gen. sp. 4 3 1 4

Gen. sp. 5 2 1 1 4 8

Oonopidae

Coxapopha sp. 1 1 1

Dysderina sp. 1 1 1 3 2 5 12Gamasomorphinae sp. 1 2 1 2 1 6

Gamasomorphinae sp. 2 1 1 2

Gamasomorphinae sp. 3 2 2

Gamasomorphinae sp. 4 1 1

Neoxyphinus sp. 1 4 5 2 1 1 1 2 16

Neoxyphinus sp. 2 1 2 5 1 1 4 1 15

Neoxyphinus sp. 3 1 3 3 3 1 2 1 3 17

Neoxyphinus sp. 4 1 1

Oonopinae sp. 1 1 1 1 1 3 7

Oonopinae sp. 2 2 1 1 4

Oonopinae sp. 3 3 3

Oonops sp. 1 2 2 4

Oonops sp. 2 1 1

Scaphiella sp. 1 1 2 1 4

Oxyopidae

Oxyopes sp. 1 1 1

Oxyopes sp. 2 3 3

Oxyopes sp. 3 15 15

Tapinillus longipes 1 1

Tapponia sp. 1 1 1 1 1 1 6

Tapponia sp. 2 1 3 4

Palpimanidae

Otiothops sp. 1 1 1

Pholcidae

Gen. sp. 1 1 1 2

Gen. sp. 2 2 2

Gen. sp. 3 3 3

Gen. sp. 4 1 1 2

Gen. sp. 5 1 1

Carapoia ocaina 2 2 3 1 1 1 1 1 12

Mesabolivarsp. 1 1 1 1 3

Mesabolivar aurantiacus 2 2 1 2 2 9

Metagonia samiria 1 1 2

Metagonia sp. 1 1 2 3

Table 2 - Continuao


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Pisaboa aff.silvae 1 1

Pisauridae

Architis sp. 1 1 2 1 2 1 2 9

Gen. sp. 1 4 5

Gen. sp. 2 2 2

Thaumasia sp. 1 2 10 12

Thaumasia sp. 2 1 7 1 2 11

Thaumasia sp. 3 1 1 1 1 4

Salticidae

Gen. sp. 1 2 4 5 11

Gen. sp. 2 4 1 1 3 1 4 14

Gen. sp. 3 1 1

Gen. sp. 4 2 2 1 4 9Gen. sp. 5 1 1

Gen. sp. 6 1 1 1 3

Gen. sp. 7 1 1

Gen. sp. 8 1 1

Gen. sp. 9 1 1

Gen. sp. 10 1 1 2

Gen. sp. 11 1 1

Gen. sp. 12 1 1 2

Gen. sp. 13 1 1 2

Gen. sp. 14 1 1

Gen. sp. 15 1 1 1 2 1 6

Gen. sp. 17 1 1 1 3

Gen. sp. 18 1 1

Gen. sp. 19 1 1

Gen. sp. 20 1 1 2 4

Gen. sp. 21 2 2

Gen. sp. 22 1 1

Gen. sp. 23 1 1 2

Gen. sp. 24 1 1 2

Gen. sp. 25 1 1 2

Gen. sp. 26 2 1 3

Gen. sp. 27 1 1 2

Gen. sp. 28 1 1

Gen. sp. 29 2 2

Gen. sp. 30 2 2

Gen. sp. 31 1 1 2

Gen. sp. 32 1 1

Gen. sp. 33 1 1

Gen. sp. 34 1 1 2

Gen. sp. 35 1 1 2

Gen. sp. 36 2 2

Gen. sp. 37 1 2 2 5

Gen. sp. 38 1 1 1 3

Gen. sp. 39 3 2 1 1 1 8

Table 2 - Continuao


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Gen. sp. 40 1 1

Gen. sp. 41 1 1

Gen. sp. 42 1 1

Gen. sp. 43 1 1

Gen. sp. 44 1 1 1 3

Gen. sp. 45 1 1 2

Gen. sp. 46 1 1

Gen. sp. 47 1 1

Gen. sp. 48 1 1

Gen. sp. 49 2 2

Gen. sp. 50 1 1

Gen. sp. 52 1 1 2

Gen. sp. 53 2 2Chira sp. 1 1 2 1 2 6

Chira sp. 2 1 1 1 1 4

Chira sp. 3 1 1 1 3

Chira sp. 4 1 1 2

Chira sp. 5 1 1 2 1 2 2 9

Cotinusa sp. 1 1 1

Lyssomanes sp. 1 1 1 1 1 1 1 6

Phiale sp. 1 1 1

Phiale sp. 2 1 1

Scytodidae

Scytodes sp. 1 2 2

Scytodes auricula 1 1 2 1 1 1 1 2 3 13

Scytodes romitti 1 1 2

Senoculidae

Senocolus sp. 1 1 1

Sparassidae

Gen. sp. 1 1 1

Gen. sp. 3 1 1

Gen. sp. 4 1 1 2

Gen. sp. 5 2 2

Gen. sp. 6 1 1 1 3

Sparianthinae sp. 1 1 1

Pseudosparianthis sp. 1 1 1 1 3

Symphytognathidae

Gen. sp. 1 1 2 2 1 6

Gen. sp. 2 1 1

Gen. sp. 3 1 1

Synotaxidae

Gen. sp. 1 1 1 2

Gen. sp. 2 1 1 2

Gen. sp. 3 1 1

Tetragnathidae

Gen. sp. 1 1 1

Gen. sp. 2 1 2 2 5 10

Table 2 - Continuao


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Chrysometa sp. 1 1 1 1 3

Leucauge sp. 1 3 1 4


Leucauge sp. 3 1 1

Leucauge sp. 4 1 1


Leucauge sp. 6 1 1

Leucauge sp. 8 1 1


Leucauge sp. 10 1 1

Leucauge sp. 11 1 1

Tetragnatha sp. 1 1 1

TheridiidaeGen. sp. 1 1 1 2

Gen. sp. 2 2 2

Gen. sp. 3 2 2

Gen. sp. 4 1 1

Gen. sp. 5 1 1

Gen. sp. 6 1 1

Gen. sp. 7 2 1 3

Gen. sp. 8 1 1

Gen. sp. 9 1 1

Gen. sp. 10 1 1

Gen. sp. 11 1 1

Gen. sp. 12 1 1

Gen. sp. 13 1 1

Gen. sp. 14 1 1

Gen. sp. 15 1 1

Gen. sp. 16 1 1

Gen. sp. 17 1 1 2

Gen. sp. 18 1 1 2 4

Gen. sp. 19 1 1

Gen. sp. 20 1 1

Gen. sp. 21 1 1

Gen. sp. 22 1 1

Gen. sp. 23 1 1

Gen. sp. 24 1 1 2

Gen. sp. 25 1 2 3

Achaearanea sp. 1 1 1 1 3

Achaearanea sp. 2 1 1 1 2 5

Achaearanea sp. 20 1 1

Anelosimus sp. 1 40 40

Argyrodes sp. 1 1 1 1 1 1 5

Argyrodes sp. 2 1 1

Argyrodes sp. 3 1 1

Argyrodes sp. 5 3 3

Argyrodes sp. 6 1 1

Table 2 - Continuao


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Argyrodes sp. 7 2 2

Cerocida aff.strigosa 1 1

Chrosiotes sp. 1 1 1

Chrosiotes sp. 2 1 1

Chrosiotes sp. 3 1 1 2

Chrysso sp. 1 1 1 1 1 1 5

Chrysso sp. 2 1 1

Chrysso sp. 3 1 1

Coleosoma acutiventer 6 6

Dipoena aff.atlantica 2 1 1 4

Dipoena aff.kuyuwini 1 1 2

Dipoena aff. donaldi 1 1 1 3

Dipoena aff. tiro 2 2Dipoena sp. 1 1 3 2 1 2 9

Dipoena sp. 2 3 1 4

Dipoena sp. 3 1 1

Dipoena sp. 4 1 1

Dipoena sp. 5 1 1

Dipoena sp. 6 1 1

Dipoena sp. 7 1 1

Dipoena sp. 8 1 1

Dipoena sp. 9 1 1

Echinotheridion sp. 1 1 1

Episinus sp. 1 4 8 9 1 3 1 1 4 4 3 38

Episinus sp. 2 1 2 1 1 2 4 1 12

Episinus sp. 3 1 1 1 3

Episinus sp. 4 1 1

Episinus sp. 5 1 1 2

Episinus sp. 6 1 1

Episinus sp. 7 1 1

Episinus sp. 8 1 1 1 3

Stemmops sp. 1 1 2 1 4

Stemmops sp. 2 1 1 2

Stemmops sp. 3 1 1

Thwaitesia bracteata 4 2 4 1 11

Theridiossomathidae

Gen. sp. 1 1 1

Gen. sp. 2 1 1

Gen. sp. 3 1 1

Naatlo sp. 1 1 1 2

Naatlo sp. 2 2 2

Naatlo sp. 3 1 3 1 5

Theridiossoma sp. 1 2 1 3

Theridiossoma sp. 2 1 1

Theridiossoma sp. 3 1 1

Theraphosidae

Cyioscosmus sp. 1 1 1

Table 2 - Continuao


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Theraphosinae sp. 1 1 1

Thomisidae

Gen. sp. 1 1 1

Ascentrocelus sp. 1 1 1

Misumenops sp. 1 1 1

Onocolus echinatus 1 1 2 4

Stephanopis sp. 1 1 4 2 1 1 9

Stephanopis sp. 2 1 1

Strophius sp. 1 1 1 2

Synaema sp. 1 1 1 2

Tmarus sp. 1 1 1

Tmarus sp. 2 1 1

Tmarus sp. 3 1 1Tmarus sp. 4 1 1

Tmarus sp. 5 2 2

Tmarus sp. 6 1 1

Tmarus sp. 7 1 1

Tmarus sp. 8 1 1

Tmarus sp. 9 1 1

Trechaleidae

Dossenus sp. 1 29 17 46

Dossenus sp. 2 7 7

Dossenus sp. 3 2 2 2 6

Trechalea sp. 1 1 1

Trechalea sp. 2 1 1 3 1 6

Trechalea macconnelli 2 2

Uloboridae

Gen. sp. 1 1 1

Miagrammopes sp. 1 1 1

Philoponella sp. 1 1 1 2

Philoponella sp. 2 1 2 1 1 1 6

Philoponella sp. 3 1 1

Uloborus sp. 1 1 1 2

Zosis aff.geniculatus 2 1 1 4

Total 168 159 153 116 158 140 206 222 163 127 1612

Table 2 - Continuao

SPECIES RICHNESS AND SIMILARITY IN ARTIFICIAL ANDNATURALS FOREST GAPS

Excluding the occasional sampling, 344 individualswere recorded in both articial and natural orest gap areas.Te 32 adult specimens were identied as comprising 357species or morphospecies recorded in 28 valid samples. oprovide an indication o the total species richness present inthe study site, the results o seven species richness estimatorsare made available or entire Porto Urucu dataset (Fig. 2). Teestimates ranged rom 2 species (Jackknie 2) to 435 species(Bootstrap). However, these results must be viewed cautiously

because the inventory is not complete. Walther & Moore(2005) stressed that each estimator has been developed to workbest under the assumptions dened by a specic populationmodel, which denes the population structure resulting romvarious community parameters. Tus, perormance testsalways must be carried out in order to veriy which estimatorts best to the particular conditions o each inventory.

oti et al. (2000), in testing a spider assemblages database,indicated that a good way to test the perormance o a givenestimator is to inspect visually the shape o the curve, lookingor trends toward the asymptote. Te best estimators would be


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those which need less inormation to approach stability. In thecase here presented, no estimator reached a clear asymptote;but ater applying the above procedure, we veried that ICE

was the best t estimator to this data set, characterized bylarge numbers o singletons and uniques. ICE (incidence-based coverage estimator) is based on the proportion ospecies presented in the samples, relies on presence/absencedata to quantiy rarity and retrieves inormation rom speciesrepresented by up to 0 individuals (oti et al., 2000; Colwell,

200). Te preerred estimated number, produced by ICE,was 3 species. Tis is the second larger estimate, beingsurpassed only by Jackknie 2. However, it is not an absurdprediction because the only spider inventory rom a nearbylocality available to comparison, the one provided by Her& Brescovit (200) or the RFAD, reported an observed (orminimal) species richness o 50 species.

Inspecting the individual-based rareaction curves orboth JAZ and NA communities (Fig. 3) at the point thata comparison is possible (55th individual added), JAZaccumulated species, while NA accumulated 228species. Tese dierences are signicant given the calculated

condence interval (

= 0.05). Te rareaction curve orNA reached a higher species richness with ewer specimensthan the JAZ curve, which needed to add 72 individuals toaccumulate only 224 species at the end o data entry.

Te values o the similarity indices or the JAZ andNA communities were 0,34 and 0,48 or Kulczynskis andSrensens indexes, respectively. At the end o the observedsample-based accumulation curves, the samples related tonatural orest gaps produced 23 species, while 230 species

were recorded rom the samples related to articial orestgaps. Despite this apparently similar observed richness, only2 species were common to these two treatments. Both

indices above depicted considerable dierences regardingspider species composition between these two communities.Te dierences between the two kinds o communities weredetectable, even considering that the collecting eort was lessintense in the center o both kinds o gaps than in its orestededges and adjacent orest matrix. In the natural orest gapso Porto Urucu, the composition o the plant communitiesdoes not dier greatly rom that o the original orest matrix,

but the articial orest gaps present more herbaceous andpioneers plants (Lima Filho et al. 200). It is possible that thedierences depicted in species richness and composition ospecies among the two spider communities refect responsesto dierences in physiognomy and plant species compositiono the gaps themselves, revealing a dierential infuence o thepresence o each kind o gap in the orest matrix.

LYCOSIDAE AND CTENIDAE AS ENVIRONMENTAL INDICATORS

Comparing the amilies represented by more than 400individuals (Fig. 4), a Mann Whitney test analyzing dierencesin abundance o Lycosidae in natural versusarticial orest gaps

areas show that representatives o this amily are much moreabundant in JAZ areas than in NA areas (U= 0; p= 0.020).On the other hand, test show that Ctenidae was moreabundant in NA than in JAZ areas (t= 3.28; p= 0.0).

Te great abundance o Ctenidae in NA areas could beexplained by a putative increase o suitable ground sheltersor these spiders, provided in the center o the NA gapsby the allen trees. In act, the gap centers contributed 202individuals out o the 35 collected in NA areas (5%).However, the results o the test could be biased by the rarityo Ctenidae in the center o the JAZ gaps (only 3 out o all7 individuals in JAZ, or 7%).

Figure 2 - Observed sampling accumulation curve and non parametricestimator performance for the data set of spiders collected in both artificial andnatural forest gap areas in Porto Urucu, Coari, Amazonas, Brazil. The testedestimators are Jackknife 1 and 2, ICE, ACE, Chao 1 and 2, and the Bootstrap.

Figure 3 - Individual-based rarefaction curves for spiders collected in bothartificial and natural forest gap areas in Porto Urucu, Coari, Amazonas, Brazil,with their respective 95% confidence interval lower and upper bounds. Solidlines, natural forest gap areas; dotted-lines, artificial forest gap areas.


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Te large number o representatives o the amily Lycosidae(N= 432) is an unusual result or tropical rain orest sites.From all individuals collected in Porto Urucu, 47 were rom

JAZ communities and only 5 were rom NA areas or romthe surroundings o the creeks. Moreover, except or eightspecimens rom the adjacent orest matrix, all specimens oLycosidae obtained in JAZ areas were collected in the gapsthemselves. Jocqu & Alderweireldt (2005) stated that lycosidsare consistently more abundant in areas covered by herbaceouslayer, which is negatively correlated with the degree o canopy

closure. In Porto Urucu, the natural orest gaps are surroundedby the primary orest and the canopy discontinuity is small.On the other hand, the articial orest gaps represent a largecanopy discontinuity, where in some areas, only herbaceousplants are present.

Te explosive abundance o Lycosidae in articial gaps,combined with its extreme rarity in the wider orest matrixqualies it as an excellent environmental indicator o orestdegraded areas. Te incidence and relative abundance oCtenidae could be also monitored, providing a complementaryindicator o recovering gap areas.

RESEARCH PERSPECTIVES IN PORTO URUCU

Te continuity o the project Dinmica de clareiras sobimpacto da explorao petrolera (DICLA), which aims toaddress some undamental questions involving communitydynamics in articial gaps in Porto Urucu, allowed us toconsiderably increase the sampling eort in the study area.Since 2005, urther studies on the spider auna were carriedout as part o the second author's PhD project. Tis projectapplied a sampling protocol designed to maximize theacquiring o data related to spider auna dynamics in articialorest gaps with various degrees o regeneration, grouping gapsin three blocks, each one with high sample representation

levels. Several occasional and ogging samples, as well asnearly 800 samples rom a protocol composed by beating tray,nocturnal hand search and Winkler extractors, are availablerom this study. Adding inormation rom these samples to thepresent dataset may help to better quantiy the environmentalimpact o the articial gaps in the spider communities presentin the orest matrix o Porto Urucu.

ACKNOWLEDGMENTS

Logistic support in the eld was provided by PetrobrasS.A.; we are grateul to M.B. Martins (MPEG) or suggestionsregarding the sampling design, to D.D. Guimares and J.O.Dias (MPEG) or helping during eld work, to A. D. Brescovit(Instituto Butantan, So Paulo, IBSP) or inormation on

previous records o spider species in Porto Urucu and to L. S.Carvalho (MPEG UFPI), A. J. Santos (Universidade Federalde Minas Gerais) and . Gardner (University o East AngliaCambridge, UK) or useul comments to the manuscript;

A.D. Brescovit, C.A. Rheims (IBSP), N. Abrahim, J.A.P.Barreiros, D.R. Santos-Souza (MPEG), E.H. Buckup andM.A. Marques (Museu de Cincias Naturais, Porto Alegre)kindly helped to identiy the material; the authors weresupported by CNPq (SCD DR grant #40722/200-8; ABBPQ grant #3035/200-3).

LITERATURE CITEDAyres, M.; Ayres Jr., M.; Ayres, D.L.; Santos, A.S. 2005. BioEstat

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Recebido em 19/02/2008Aceito em 16/06/2009

bonaldo y dias, 2010

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