Abstract booklet - gtö – Society for Tropical Ecology

174 SCIENTIFIC POSTER SESSION | FOYERSCIENTIFIC POSTER SESSION | FOYER175Free contributionFree contribution – invasive speciesEDGE EFFECTS ON THE DENSITY OF TREEFALL GAPS INTHE BRAZILIAN ATLANTIC FORESTALIEN PLANTS IN ARID AREAS: THE CASE OF THE BRAZILIANCAATINGAWalkiria Rejane Almeida 1 , Manoel Vieira de Araujo Jr. 1 , ElâineMaria Santos Ribeiro 1 , Inara Roberta Leal 2Walkiria Rejane Almeida 1 , Ariadna Valentina Lopes 2 , Inara Roberta Leal 21PPGBV - UFPE, Recife, BR, walreal@yahoo.com.br, 2 Departamento de Botânica,UFPE, Recife, BRWEDNESDAY | FOYER1PPGBV - UFPE, Recife, BR, walreal@yahoo.com.br, 2 Departamento deBotânica, UFPE, Recife, BRWe investigated the structure and density of treefall gaps withincreasing distance from the forest edge towards the forest interiorin a large remnant of the Atlantic Forest in northeastern Brazil. Wehypothesized that due to edge effects, treefall gaps are (1) morefrequent, (2) more recent, (3) smaller in size and adjacent canopyheight, and (4) formed more often by uprooting and snap. Using thetransect method (n = 24 transects, with surveyed area of 38 ha), wemarked all treefall gaps we found with a GPS and measured theirarea, adjacent canopy height, age, and origin. The density of treefallgaps did not change with the distance from the forest edge (0.54± 1.88 to 2.99 ± 4.20 treefall gaps/ha [lower to higher density]; H =8,86; df = 11; p = 0,58), occurring uniformly in 12 different distancezones (0-50m, 50-100m, 100-150m, 150-200m, 200-250m, 250-300m, 300-350m, 350-400m, 400-450m, 450-500m, 500-550m and>550m). The disturbance regime was characterized by treefall gapspredominantly small (Introduction and spread of alien species are considered one of the main threatsto biodiversity. Although a large body of literature exists on the impacts ofplant invasion, as for the savannas in the Neotropics and northern Australia, theimpacts of alien species in several other ecosystems is lacking. For instance, eventhe identity of alien plants in Caatinga, a semi-arid ecosystem in northeasternBrazil, has not been described. The goal of this study is to dtermine the exoticflora of the Caatinga, assess its taxonomic composition, as well as the historyof invasion and the biological attributes of these species. A total of 213 alienplant species was recorded for Caatinga, distributed over 175 genera and 67families. The families with the largest number of alien species were Fabaceae(38 species), Poaceae (35), and Asteraceae (16), accounting for 41.8% of allspecies; 38 families were represented by only one species, and 25 families by sixspecies or less. The most speciose genera were Urochloa (7 species), Mimosa (4),Crotalaria, Euphorbia, Sorghum, and Thunbergia (3). About 39% of the speciesbelonged to non-native genera in the Caatinga. Alien plant species in Caatingaoriginated from all continents, but the Old World accounted for 66.3%, with mostspecies originating from Asia (33.5%) and Africa (22.8%). The most commonbiological attributes of alien plant species included (1) perennial herbs (57.3%),(2) pollination by bees (51.9%), (3) hermaphrodites (70%), (4) self-compatible(53.8%), (5) capsule fruits (24.4%), and (6) dispersal by animals (44%). In general,the most frequent vegetative and reproductive biological attributes among theexotic species appear to reflect the predominance of non-specialized strategiesinvolved in ecological processes driving the dynamics of plant populations.Wednesday WEDNESDAY 16:00 | FOYER | FoyergtöSociety for Tropical Ecology | Gesellschaft für Tropenökologie e.V. Status and future of tropical biodiversity | Frankfurt, 21 - 24 February 2011gtö