Check List 10(2): 366–373, 2014 © 2014 Check List and Authors Chec List ISSN 1809-127X (available at www.checklist.org.br) Journal of species lists and distribution Floristic diversity of the Cagarras Islands Natural PECIES S Monument, Rio de Janeiro, Brazil OF Massimo G. Bovini 1*, Marcos Faria 2, Rogério R. Oliveira 3 and Bruno C. Kurtz 1 ISTS L Janeiro, RJ, Brazil. 2 1 Instituto Marde Pesquisas Adentro. JardimRua Barata Botânico Ribeiro do Rio391/901, de Janeiro. CEP 22040-000,Diretoria de Copacabana, Pesquisa Científica. Rio de Janeiro, Rua Pacheco RJ, Brazil. Leão 915, Horto, CEP 22460-030, Rio de * Corresponding author. E-mail: [email protected] 3 Pontifícia Universidade Católica do Rio de Janeiro, Departamento de Geografia, CEP 22453-900, Rio de Janeiro, RJ, Brazil. Abstract: Janeiro, Brazil, and a total of 171 species were encountered. The families with the greatest richnesses were: Asteraceae (12 spp.), Myrtaceae The vascular (12), Fabaceae flora was (11), inventoried Bromeliaceae of the Cagarras(7), Cactaceae Islands (6), Natural Euphorbiaceae Monument (6), (CINM) and Poaceae located offshore(6). The ofregional Rio de vegetation was similar to restinga, although high concentrations of guano from nesting marine birds affected diversity on two islands. The threatened species Gymanthes nervosa Müll. Arg. was recorded from the municipality of Rio de Janeiro for the first time since the 1940s. Introduction were undertaken by R. Oliveira in 1980 and A.S. Rodrigues Islands have an enormous importance in terms of in 2000, with sporadic collecting on the archipelago global biodiversity conservation, as approximately one islands (see Rodrigues et al. 2007). quarter (~70,000) of all known plant species are endemic The present study presents a species list of the to islands. Species richness is principally determined by an island’s size, its degree of geographical isolation, Cagarras Islands Natural Monument, to increase our and present climatic conditions (Kreft et al. 2008). knowledgeterrestrial floraof the of vegetation the islands growing of the there recently and providecreated Unfortunately, island biotas are now seriously threatened subsidies for regional conservation planning. by habitat losses and climate change, and are particularly et al. 2010). Materials and Methods Research projects focusing on island vegetations have Study site beensensitive relatively to biological rare in invasionsBrazil, whether (Serafini coastal (e.g., Barros The Cagarras Islands National Monument (CINM) et al. 1991; Menezes-Silva 1998; Oliveira 2002; Kemenes was created by Federal Law 12,229 on April 13, 2010, 2003; Bovini et al. 2013) or oceanic (e.g., Batistella 1996; and is administered by the Instituto Chico Mendes de Alves 1998, 2006; Gasparini 2004) – in spite of the fact Conservação da Biodiversidade – ICMBio. The reserve is located in the municipality of Rio de Janeiro, RJ, Brazil, and communities are of fundamental importance to evaluations comprises four large islands (Palmas, Comprida, Cagarra, ofthat their the conservationidentification statuses. and description The low ofresilience island plant(and and Redonda) and two smaller ones (Filhote da Redonda consequent fragility) of these environments demands and Filhote da Cagarra) (Figures 1 and 2) as well as marine areas extending outward for 10 m from them, with a total guarantee their conservation. area of approximately 90 ha. The islands are located specialRocky consideration islands along and the specific coast managementof Rio de Janeiro policies State to between 3.8 and 8.6 km from Arpoador Point (the closest are important landscape elements that contribute to both mainland area). The highest point of the CIMN is located marine and terrestrial diversity (e.g., Bastos and Callado on Redonda Island (240 m above sea level) and the lowest 2009; Moraes et al. 2013). These islands were linked to site on Comprida Island (approximately 30 m a.s.l.). the mainland during the last glacial period (Wisconsin), The soils on the islands are basically residuals, but whose maximum occurred approximately 17,000 years those on Cagarra and Redonda islands have high levels ago, when the sea level was approximately 110 m lower of phosphorus due to the huge deposits of guano left by than today (Tessler and Goya 2005), which allowed greater Fregata magnificens Sula leucogaster (Brown Booby). Phosphorus concentrations The Cagarras Archipelago is an important ecological can reach toxic levels (Magnificent and limit Frigatebirds)the numbers andof plant refugemigratory situated flux. just off the coast from Rio de Janeiro, but its species that can prosper there (Rodrigues et al. 2007). According to Cunha et al. (2013), the CINM is the second (Moraes et al. 2013). The islands (and surrounding marine largest roosting area of marine birds along the Brazilian areas)fauna and have flora important have been roles little studiedin regional until quitetourism recently and coast. receive many visitors during the summer months (Aguiar et al Data collection (Moraes et al Botanical material was collected during monthly . 2013), as well as fishermen throughout the year . 2013a). The first studies of the local flora 366 Bovini et al. | Flora of the Cagarras Islands Natural Monument, Brazil expeditions to the four main and two smaller islands (sandy, open, nearshore vegetation), showing the clumped between July 2011 and February 2013, using the “walking” associations typical of this environment, and abundant survey method (Filgueiras et al. 1994). Fertile plant species such as Abutilon esculentum , Clusia material was dried using traditional botanical methods fluminensis Planch. & Triana, Hylocereus setaceus (Salm- and incorporated into the herbarium at the Instituto de Dyck) R.Bauer, and Neoregelia cruenta (R.Graham) A.St.-Hil. L.B.Sm. Pesquisas Jardim Botânico do Rio de Janeiro (RB). The One of the most prominent species in island forests was Syagrus romanzoffiana (Cham.) Glassman (common comparisons with illustrations in the specialized literature name “jerivá”). This palm tree was widely distributed in andplants with were collections identified depositedusing the literature,in the RB, as R well(National as by southeastern and southern Brazil (Lorenzi et al. 2004) Museum), and GUA (INEA, Instituto Estadual do Ambiente) and in the coastal mountains of Rio de Janeiro State, and herbaria and, when necessary, by consulting specialists. is common on the higher areas of the Palmas and Redonda islands (Figure 3). The island vegetation grows under environmental ResultsThe APG IIIand (2009) Discussion classification system was followed. conditions distinct from those found on the continent, A total of 169 species belonging to 60 families were as the archipelago is relatively distant from propagule encountered in the CINM (Table 1). The most species rich families were: Asteraceae (12 species), Myrtaceae occurring along the mainland coast. (12), Fabaceae (11), Euphorbiaceae (6), Cactaceae (6), sourcesThe numbers and is notof species influenced on each by island the orographicwas very variable rains Bromeliaceae (6), and Poaceae (6). (Table 1) and did not appear to be directly dependent The vegetation of the CINM demonstrated variable on the sizes of the islands or on the heterogeneity of physiognomies on different islands, with plant heights available habitats. According to Bovini et al. (2013), the and densities being related to factors such as landscape presence of nesting frigatebirds and brown boobies and declivity, substrate type, and exposition – with vegetation the consequent excesses of phosphorus in the island soils formations varying from herbaceous to low forests. In many areas the vegetation was typical of “restinga” Cagarra and Redonda islands. As such, Comprida Island hadcontribute the largest to strong number reductions of species in the(98) floristic (Table diversity1), which on is probably related to its relatively large size and complete absence of nesting marine birds; the second most species rich island (Palmas) likewise had no nesting birds. Cagarra Island, which has with the highest concentrations of (23 species). nesting sites in the CINM, had the lowest floristic richness being threatened with extinction to some degree according to theFifteen MMA of list the (2008, species Annex encountered I and II); thewere municipality classified asof Rio de Janeiro (Di Maio and Silva 2000); and the site of the Centro Nacional de Conservação da Flora (CNCFlora 2013): Allagoptera arenaria (Gomes) Kuntze (Figure 4a), Begonia hirtella Link, Alcantarea glaziouana (Leme) J.R.Grant Figure 1. Map of study area. Detail of the CIMN, RJ, Brazil; 1) Palmas (Figure 4b), Neoregelia cruenta (R.Graham) L.B.Sm. (Figure Island; 2) Cagarra Island; 3) Filhote da Cagarra Island; 4) Comprida 4c), Tillandsia araujei Mez, Coleocephalocereus fluminensis Island; 5) Redonda Island; 6) Filhote da Redonda Island. (Miq.) Backeb, Clusia fluminensis Planch. & Triana, Gymnanthes nervosa Müll. Arg., Plinia ilhensis G.M.Barroso, Cattleya forbesii Lindl., Microgramma crispata (Fée) R.M.Tryon & A.F.Tryon, Rudgea minor (Cham.) Standl., Rudgea umbrosa Müll. Arg., Manilkara subsericea (Mart.) Dubard, and Cissus serroniana (Glaz.) Lombardi. Following literature searches, and our consultations of herbarium collections, it was discovered that Gymnanthes nervosa had not been collected since the 1940s, and was only found at the highest point in the CIMN on Redonda Island. Some Most of the species encountered in the CINM are sharedCIMN species with the