Cultural phylogeography of the Bantu Languages of sub-Saharan Africa

There is disagreement about the routes taken by populations speaking Bantu languages as they expanded to cover much of sub-Saharan Africa. Here, we build phylogenetic trees of Bantu languages and map them onto geographical space in order to assess the likely pathway of expansion and test between dispersal scenarios. The results clearly support a scenario in which groups first moved south through the rainforest from a homeland somewhere near the Nigeria–Cameroon border. Emerging on the south side of the rainforest, one branch moved south and west. Another branch moved towards the Great Lakes, eventually giving rise to the monophyletic clade of East Bantu languages that inhabit East and Southeastern Africa. These phylogenies also reveal information about more general processes involved in the diversification of human populations into distinct ethnolinguistic groups. Our study reveals that Bantu languages show a latitudinal gradient in covering greater areas with increasing distance from the equator. Analyses suggest that this pattern reflects a true ecological relationship rather than merely being an artefact of shared history. The study shows how a phylogeographic approach can address questions relating to the specific histories of certain groups, as well as general cultural evolutionary processes.

General circulation model estimates of aerosol transport and radiative forcing during the Indian Ocean Experiment

Aerosol sources, transport, and sinks are simulated, and aerosol direct radiative effects are assessed over the Indian Ocean for the Indian Ocean Experiment (INDOEX) Intensive Field Phase during January to March 1999 using the Laboratoire de Me´te´orologie Dynamique (LMDZT) general circulation model. The model reproduces the latitudinal gradient in aerosol mass concentration and optical depth (AOD). The model-predicted aerosol concentrations and AODs agree reasonably well with measurements but are systematically underestimated during high-pollution episodes, especially in the month of March. The largest aerosol loads are found over southwestern China, the Bay of Bengal, and the Indian subcontinent. Aerosol emissions from the Indian subcontinent are transported into the Indian Ocean through either the west coast or the east coast of India. Over the INDOEX region, carbonaceous aerosols are the largest contributor to the estimated AOD, followed by sulfate, dust, sea salt, and fly ash. During the northeast winter monsoon, natural and anthropogenic aerosols reduce the solar flux reaching the surface by 25 W m�2, leading to 10–15% less insolation at the surface. A doubling of black carbon (BC) emissions from Asia results in an aerosol single-scattering albedo that is much smaller than in situ measurements, reflecting the fact that BC emissions are not underestimated in proportion to other (mostly scattering) aerosol types. South Asia is the dominant contributor to sulfate aerosols over the INDOEX region and accounts for 60–70% of the AOD by sulfate. It is also an important but not the dominant contributor to carbonaceous aerosols over the INDOEX region with a contribution of less than 40% to the AOD by this aerosol species. The presence of elevated plumes brings significant quantities of aerosols to the Indian Ocean that are generated over Africa and Southeast and east Asia.

The dependence of high-latitude dayside ionospheric flows on the North-South component of the IMF: A high time resolution correlation analysis using EISCAT “Polar” and AMPTE UKS and IRM data

In 1984 and 1985 a series of experiments was undertaken in which dayside ionospheric flows were measured by the EISCAT “Polar” experiment, while observations of the solar wind and interplanetary magnetic field (IMF) were made by the AMPTE UKS and IRM spacecraft upstream from the Earth's bow shock. As a result, 40 h of simultaneous data were acquired, which are analysed in this paper to investigate the relationship between the ionospheric flow and the North-South (Bz) component of the IMF. The ionospheric flow data have 2.5 min resolution, and cover the dayside local time sector from ∼ 09:30 to ∼ 18:30 M.L.T. and the latitude range from 70.8° to 74.3°. Using cross-correlation analysis it is shown that clear relationships do exist between the ionospheric flow and IMF Bz, but that the form of the relations depends strongly on latitude and local time. These dependencies are readily interpreted in terms of a twinvortex flow pattern in which the magnitude and latitudinal extent of the flows become successively larger as Bz becomes successively more negative. Detailed maps of the flow are derived for a range of Bz values (between ± 4 nT) which clearly demonstrate the presence of these effects in the data. The data also suggest that the morning reversal in the East-West component of flow moves to earlier local times as Bz, declines in value and becomes negative. The correlation analysis also provides information on the ionospheric response time to changes in IMF Bz, it being found that the response is very rapid indeed. The most rapid response occurs in the noon to mid-afternoon sector, where the westward flows of the dusk cell respond with a delay of 3.9 ± 2.2 min to changes in the North-South field at the subsolar magnetopause. The flows appear to evolve in form over the subsequent ~ 5 min interval, however, as indicated by the longer response times found for the northward component of flow in this sector (6.7 ±2.2 min), and in data from earlier and later local times. No evidence is found for a latitudinal gradient in response time; changes in flow take place coherently in time across the entire radar field-of-view.

Evolution of Dendrocolaptes platyrostris (Aves: Furnariidae) between the South American open vegetation corridor and the Atlantic forest

The open vegetation corridor of South America is a region dominated by savanna biomes. It contains forests (i.e. riverine forests) that may act as corridors for rainforest specialists between the open vegetation corridor and its neighbouring biomes (i.e. the Amazonian and Atlantic forests). A prediction for this scenario is that populations of rainforest specialists in the open vegetation corridor and in the forested biomes show no significant genetic divergence. We addressed this hypothesis by studying plumage and genetic variation of the Planalto woodcreeper Dendrocolaptes platyrostris Spix (1824) (Aves: Furnariidae), a forest specialist that occurs in both open habitat and in the Atlantic forest. The study questions were: (1) is there any evidence of genetic continuity between populations of the open habitat and the Atlantic forest and (2) is plumage variation congruent with patterns of neutral genetic structure or with ecological factors related to habitat type? We used cytochrome b and mitochondrial DNA control region sequences to show that D. platyrostris is monophyletic and presents substantial intraspecific differentiation. We found two areas of plumage stability: one associated with Cerrado and the other associated with southern Atlantic Forest. Multiple Mantel tests showed that most of the plumage variation followed the transition of habitats but not phylogeographical gaps, suggesting that selection may be related to the evolution of the plumage of the species. The results were not compatible with the idea that forest specialists in the open vegetation corridor and in the Atlantic forest are linked at the population level because birds from each region were not part of the same genetic unit. Divergence in the presence of gene flow across the ecotone between both regions might explain our results. Also, our findings indicate that the southern Atlantic forest may have been significantly affected by Pleistocene climatic alteration, although such events did not cause local extinction of most taxa, as occurred in other regions of the globe where forests were significantly affected by global glaciations. Finally, our results neither support plumage stability areas, nor subspecies as full species. (C) 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 801-820.

Composição e abundância da ictiofauna de duas lagunas costeiras da América do Sul Austral: lagoa do Peixe (31ºS; 51ºW), Brasil e laguna Mar Chiquita (37ºS; 57ºW), Argentina

This article describes and compares the shallow water fish-fauna from two coastal lagoons (Peixe Lagoon, in Brazil, and Mar Chiquita Lagoon, in Argentina). Peixe Lagoon was sampled between 2000 and 2001 using a 9 m beach seine net (12 mm bar mesh in the wings and 5 mm in the centre 3 m section) totalizing 125 samples, which yielded 33,848 individuals and 32 species. Mar Chiquita Lagoon was sampled from 1995 to 1998 using a 21) m beach seine net (12 mm bar mesh) totalizing 232 samples resulting in 31,097 individuals of 28 species. A total of 47 species were observed in both lagoons and 13 were shared. The "marine-estuarine-related" species were similar and dominate the fish assemblages in both lagoons. The remaining species were similar to the species collected along the southern Brazil, Uruguay and Argentina estuaries. The number of species observed in Peixe Lagoon (S = 32) was higher than in Mar Chiquita Lagoon (S = 28) and is probably associated with a strong latitudinal gradient of species richness increasing from north to south. Considering that the Peixe Lagoon and Mar Chiquita Lagoon are isolated by the large estuaries of Patos Lagoon and Prata River, the composition of the species with low abundance and occasional occurrence were different for each local studied. These results expand the knowledge for the fauna of both sites and help conservation and management from both lagoons.

Vertebrate dispersal syndromes along the Atlantic forest: broad-scale patterns and macroecological correlates

Aim To assess the geographical variation in the relative importance of vertebrates, and more specifically of birds and mammals, as seed dispersal agents in forest communities, and to evaluate the influence of geographical and climatic factors on the observed trends.Location One hundred and thirty-five forest communities in the Brazilian Atlantic forest.Methods We collected data on dispersal modes for 2292 woody species. By combining species x site with species x trait matrices, we obtained the percentages of endozoochory, ornithochory, mastozoochory and the mean fruit diameter for the local forest communities. We used Spearman's correlation to assess bivariate relationships between variables. Subsequently, we performed paired t-tests to verify if variations in frequency of dispersal modes and mean fruit diameter were influenced by altitude or temperature. Then, we applied multiple linear regressions to evaluate the effect of geographical and climatic variables on variation in the relative frequency of dispersal modes and mean fruit diameter across communities.Results We found no consistent latitudinal or longitudinal trend in the percentage of vertebrate-dispersed species, neither bird- nor mammal-dispersed species along the Atlantic forest. Endozoochory was affected chiefly by annual mean rainfall, increasing towards moister sites. Forest communities located at higher altitudes had a higher percentage of bird-dispersed species. Even when sites with identical values of annual mean temperature were compared, altitude had a positive effect on ornithochory. Conversely, we found a higher percentage of mammal-dispersed species in warmer forests, even when locations at the same altitudinal belts were contrasted. Fruit diameter was clearly related to altitude, decreasing towards higher elevations.Main conclusions This is the first analysis of a large data set on dispersal syndromes in tropical forest communities. Our findings support the hypotheses that: (1) geographical variation in the relative number of fleshy fruit species is mainly driven by moisture conditions and is relatively independent of geographical location, and (2) broad-scale trends in fruit size correspond to geographical variation in the relative importance of mammals and birds as seed dispersal agents at the community level.

Florística e fitossociologia em parcelas permanentes da Mata Atlântica do sudeste do Brasil ao longo de um gradiente altitudinal

This paper summarizes floristic and phytossociology data of 11, out of 14 plots of 1 ha, allocated along an altitudinal gradient in the Serra do Mar, Silo Paulo, Brazil. The study was conducted at Serra do Mar State Park and the plots start at the sea level (10 m - plot of Restinga Forest that occurs at Praia da Fazenda, Picinguaba, municipality of Ubatuba) up to 1100 m above sea level (the Montane Ombrophilous Dense occurs alongside the Itamambuca Trail, municipality of Silo Luis do Paraitinga). The Restinga Forest occurs in Pleistocenic Coastal Plain where the soil is classified as a sandy Quartzipsamment (Quartzenic Neosol), while along the slopes of the Serra do Mar, the Ombrophylus Dense Forest grows on the top of a pre-Cambrian crystalline basement with granitic rocks, where the soil is a sandy-loam Dystrophic Inceptisol (Cambisol/Latosol). In all 14 plots soils are acidic (pH 3 - 4), chemically poor, with high dilution of nutrients and high saturation of aluminum. In the Restinga and at the foot of the slope the climate is Tropical/Subtropical Humid (Af/Cfa), with no dry season, an average annual rainfall over 2,200 mm and an average annual temperature of 22 degrees C. Towards the top of the Serra do Mar there is a gradual cooling along the slope, but there is no reduction in rainfall, so at 1,100 m above sea level the climate is classified as Humid Subtropical (Cfa/Cfb), with no dry season and an average annual temperature of 17 degrees C. It is important to remark that, almost daily, from 400 m above sea level up to the top of slopes the mountains are covered by a dense fog. In the 14 plots 21,733 individuals with DBH >= 4.8 cm, including trees, palms and ferns, were marked, measured and sampled. The average number of individuals sampled in each plot was 1264 ind.ha(-1)(+/- 218 SE 95%). Within the parameters considered trees prevailed (71% in the Montane ODF to 90% in the Restinga Forest), followed by palms (10% in the RF and 25% in the Montane Ombrophilous Dense Forest/ODF) and ferns (0% % in the RF and 4% in the Montane ODF). Regarding these proportions the Exploited Lowlands ODF differs from the others with only 1.8% of palm trees and striking 10% of ferns. The forest canopy is irregular with heights ranging from 7 to 9 m, rarely emergent trees reach 18 m, and due to this irregularity of the canopy the amount of light that gets through sets conditions for the development of hundreds of epiphytic species. Aside from Montana ODF, where the number of dead trees was more than 5% of individuals sampled, in the other phytophysiognomies this value was below 2.5%. In the 11 plots where the floristic study was conducted we found 562 species in 195 genera and 68 families. Only seven species - Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. and Marlierea tomentosa Cambess (both Myrtaceae), Guapira opposita (Veil.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae), Cecropia glaziovii Snethl. and Coussapoa microcarpa (Schott) Rizzini (both Urticaceae) - occurred from Restinga to Montane ODF, while 12 other species did not occur only in the Restinga Forest. Families with the greatest number of species are Myrtaceae (133 spp), Fabaceae (47 spp), Rubiaceae (49) and Lauraceae (49) throughout the gradient and Monimiaceae (21) specifically in portions Montane ODF. Only in the F plot, where logging has occurred between 1950 and 1985, the abundance of palm trees has been replaced by Cyatheaceae. The study shows a peak of diversity and richness, Shannon-Weiner index (H') ranging from 3.96 to 4.48 nats.ind(-1), in the intermediate altitudes (300 to 400 m) along the slope. Several explanations for this result are raised here, including the fact that these elevations are within the limits expansions and retractions of the different phytophysiognomies of the Atlantic ODF due to climate fluctuations during the Pleistocene. The results presented in this paper demonstrate the extraordinary richness of tree species of the Atlantic Rainforest from the northeastern coast of the State of São Paulo, reinforcing the importance of its conservation throughout the altitudinal gradient. The richness of this forest justifies a long term commitment to study its dynamics and functioning through permanent plots, and monitor the impacts of climate change in this vegetation.

Comparison of body size, relative growth and size at onset sexual maturity of Uca uruguayensis (Crustacea: Decapoda: Ocypodidae) from different latitudes in the south-western Atlantic

Some crustaceans show variations of their reproductive biology within their geographical distribution, and knowledge about such variations is important for the comprehension of their reproductive adaptations. This study compared two populations of the fiddler crab Uca uruguayensis from two locations on the south-western Atlantic coast: Ubatuba Bay, São Paulo, Brazil and Samborombón Bay, Buenos Aires, Argentina. The population features analysed were the body size variation (carapace width = CW) and the size at the onset of sexual maturity (SOM) in order to test the hypothesis that the size at SOM, should be the same in relative terms (RSOM), independently of the latitudinal position. In the Brazilian population the CW ranged from 4.18 to 11.60 mm for males and 3.90 to 9.80 mm for females, and in the Argentinean population from 3.60 to 14.10 mm for males and 2.85 to 12.00 mm for females. In the Brazilian population the SOM was 7.1 (RSOM = 0.58) and 5.9 mm CW (RSOM = 0.57) for males and females, respectively, and in the Argentinean population it was 7.0 (RSOM = 0.42) and 6.75 mm CW (RSOM = 0.53) for males and females, respectively. This fact is probably related to a great plasticity in the life history features of Uca uruguayensis under different environmental conditions. © 2012 Marine Biological Association of the United Kingdom.

Macroecologia de cetáceos marinhos (ordem cetacea)

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Variação genética e adaptabilidade evolutiva de Rhizoctonia solani AG-1 da soja sob condições de estresse

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biologia e ecologia de crustáceos decápodos (Caridea e Brachyura) do infralitoral não consolidado da costa sudeste do Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Drivers of clutch-size in Fork-tailed Flycatchers (Tyrannus savana) at temperate and tropical latitudes in South America

Many species of birds exhibit a latitudinal gradient in annual reproductive investment, laying more eggs and producing more nestlings at higher latitudes. However, few studies have evaluated the mechanisms that underlie such patterns and such differences in grassland birds specifically. We monitored nests of Fork-tailed Flycatchers (Tyrannus savana) over two breeding seasons at a tropical site in Bolivia (in 2010-11 and 2011-12) and three breeding seasons at a southern temperate site in Argentina (2010-11, 2011-12 and 2012-13), testing two hypotheses explaining variation in clutch-size among populations: the food-limitation hypothesis and the nest-predation hypothesis. Mean clutch-size and mean brood-size were significantly larger at the temperate study site than at the tropical site. Availability of arthropod food per individual bird was significantly higher at the temperate site. There was no relationship, positive or negative, between rates of nest predation and either clutch- or brood-size, and thus no support for the nest-predation hypothesis. We conclude that food availability explains much of the latitudinal variation in clutch-size in this species. We discuss avenues for future research on the mechanisms underlying geographical variation in the life histories of Neotropical birds.

Can the pattern of juvenile recruitment and population structure of the speckled swimming crab Arenaeus cribrarius (Decapoda: Brachyura) be determined by geographical variations?

This study evaluated the effect of environmental stimuli and selective pressures in different geographical areas along a latitudinal gradient, on the juvenile recruitment, population structure, and sex ratio of the speckled swimming crab Arenaeus cribrarius. Samples were collected monthly during 1 year in three locations along the Brazilian coast: Macaé, state of Rio de Janeiro (MAC, 22°47′ S, 41°45′ W); Ubatuba, São Paulo (UBA, 23°27′ S, 44°58′ W); and São Francisco do Sul, Santa Catarina (SFS, 26°08′ S, 48°34′ W). The specimens of A. cribrarius were identified, counted, sexed, and measured for maximum carapace width (CW). The largest juvenile found was in UBA (47.7 ± 1.36 mm); and the largest adult females and males in MAC (74.26 ± 0.93 and 77.04 ± 0.79 mm, respectively). Recruitment in MAC was continuous, whereas in UBA and SFS, recruitment showed seasonal characteristics. The sex ratio was skewed toward females only in UBA; in MAC and SFS, males and females were present in equal proportions. These results indicate that geographical variations can cause differences in the recruitment and population structure of A. cribrarius. These regional differences call attention to the necessity for improved management plans and control of shrimp fishing, which can affect population patterns such as juvenile recruitment, population structure and life history of the target species and species that are caught in bycatch from shrimping, such as the swimming crab A. cribrarius.

Florística e fitossociologia em parcelas permanentes da Mata Atlântica do sudeste do Brasil ao longo de um gradiente altitudinal

Este trabalho resume os dados de florística e fitossociologia de 11, das 14 parcelas de 1 ha, alocadas ao longo do gradiente altitudinal da Serra do Mar, São Paulo, Brasil. As parcelas começam na cota 10 m (Floresta de Restinga da Praia da Fazenda, município de Ubatuba) e estão distribuídas até a cota 1100 m (Floresta Ombrófila Densa Montana da Trilha do rio Itamambuca, município de São Luis do Paraitinga) abrangendo os Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar. Na Restinga o solo é Neossolo Quartzarênico francamente arenoso, enquanto que na encosta o solo é um Cambisolo Háplico Distrófico argilo-arenoso, sendo que todas as parcelas apresentaram solo ácido (pH 3 – 4) com alta diluição de nutrientes e alta saturação de alumínio. Na Restinga e no sopé da encosta o clima é Tropical/Subtropical Úmido (Af/Cfa), sem estação seca, com precipitação média anual superior a 2.200 mm e temperatura média anual de 22 °C. Subindo a encosta mantêm-se a média de precipitação, mas há um gradativo resfriamento, de forma que a 1.100 m o clima é Subtropical Úmido (Cfa/Cfb), sem estação seca, com temperatura média anual de 17 °C. Destaca-se ainda que, quase diariamente, a parte superior da encosta, geralmente acima de 400 m, é coberta por uma densa neblina. Nas 14 parcelas foram marcados, medidos e amostrados 21.733 indivíduos com DAP ≥ 4,8 cm, incluindo árvores, palmeiras e fetos arborescentes. O número médio de indivíduos amostrados nas 14 parcelas foi de 1.264 ind.ha–1 (± 218 EP de 95%). Dentro dos parâmetros considerados predominaram as árvores (71% FOD Montana a 90% na Restinga), seguidas de palmeiras (10% na Restinga a 25% na FOD Montana) e fetos arborescentes (0% na Restinga a 4% na FOD Montana). Neste aspecto destaca-se a FOD Terras Baixas Exploradas com apenas 1,8% de palmeiras e surpreendentes 10% de fetos arborescentes. O dossel é irregular, com altura variando de 7 a 9 m, raramente as árvores emergentes chegam a 18 m, e a irregularidade do dossel permite a entrada de luz suficiente para o desenvolvimento de centenas de espécies epífitas. Com exceção da FOD Montana, onde o número de mortos foi superior a 5% dos indivíduos amostrados, nas demais fitofisionomias este valor ficou abaixo de 2,5%. Nas 11 parcelas onde foi realizado o estudo florístico foram encontradas 562 espécies distribuídas em 195 gêneros e 68 famílias. Apenas sete espécies – Euterpe edulis Mart. (Arecaceae), Calyptranthes lucida Mart. ex DC. e Marlierea tomentosa Cambess (ambas Myrtaceae), Guapira opposita (Vell.) Reitz (Nyctaginaceae), Cupania oblongifolia Mart. (Sapindaceae) e as Urticaceae Cecropia glaziovii Snethl. e Coussapoa microcarpa (Schott) Rizzini – ocorreram da Floresta de Restinga à FOD Montana, enquanto outras 12 espécies só não ocorreram na Floresta de Restinga. As famílias com o maior número de espécies são Myrtaceae (133 spp), Fabaceae (47 spp), 125 Fitossociologia em parcelas permanentes de Mata Atlântica http://www.biotaneotropica.org.br/v12n1/pt/abstract?article+bn01812012012 http://www.biotaneotropica.org.br Biota Neotrop., vol. 12, no. 1 Introdução A Mata Atlântica sensu lato (Joly et al. 1999) é a segunda maior floresta tropical do continente americano (Tabarelli et al. 2005). A maior parte dos Sistemas de Classificação da vegetação brasileira reconhece que no Domínio Atlântico (sensu Ab’Saber 1977) esse bioma pode ser dividido em dois grandes grupos: a Floresta Ombrófila Densa, típica da região costeira e das escarpas serranas com alta pluviosidade (Mata Atlântica – MA – sensu stricto), e a Floresta Estacional Semidecidual, que ocorre no interior, onde a pluviosidade, além de menor, é sazonal. Na região costeira podem ocorrer também Manguezais (Schaeffer-Novelli 2000), ao longo da foz de rios de médio e grande porte, e as Restingas (Scarano 2009), crescendo sobre a planície costeira do quaternário. No topo das montanhas, geralmente acima de 1500 m, estão os Campos de Altitude (Ribeiro & Freitas 2010). Em 2002, a Fundação SOS Mata Atlântica em parceria com o INPE (Instituto..., 2002) realizaram um levantamento que indica que há apenas 7,6% da cobertura original da Mata Atlântica (s.l.). Mais recentemente Ribeiro et al. (2009) refinaram a estimativa incluindo fragmentos menores, que não haviam sido contabilizados, e concluíram que resta algo entre 11,4 e 16% da área original. Mesmo com esta fragmentação, o mosaico da Floresta Atlântica brasileira possui um dos maiores níveis de endemismos do mundo (Myers et al. 2000) e cerca da metade desses remanescentes de grande extensão estão protegidos na forma de Unidades de Conservação (Galindo & Câmara 2005). Entre os dois centros de endemismo reconhecidos para a MA (Fiaschi & Pirani 2009), o bloco das regiões sudeste/sul é o que conserva elementos da porção sul de Gondwana (Sanmartin & Ronquist 2004), tido como a formação florestal mais antiga do Brasil (Colombo & Joly 2010). Segundo Hirota (2003), parte dos remanescentes de MA está no estado de São Paulo, onde cerca de 80% de sua área era coberta por florestas (Victor 1977) genericamente enquadradas como Mata Atlântica “sensu lato” (Joly et al. 1999). Dados de Kronka et al. (2005) mostram que no estado restam apenas 12% de área de mata e menos do que 5% são efetivamente florestas nativas pouco antropizadas. Nos 500 anos de fragmentação e degradação das formações naturais, foram poupadas apenas as regiões serranas, principalmente a fachada da Serra do Mar, por serem impróprias para práticas agrícolas. Usando o sistema fisionômico-ecológico de classificação da vegetação brasileira adotado pelo IBGE (Veloso et al. 1991), a Floresta Ombrófila Densa, na área de domínio da Mata Atlântica, foi subdividida em quatro faciações ordenadas segundo a hierarquia topográfica, que refletem fisionomias de acordo com as variações das faixas altimétricas e latitudinais. No estado de São Paulo, na latitude entre 16 e 24 °S temos: 1) Floresta Ombrófila Densa das Terras Baixas - 5 a 50 m de altitude; 2) Floresta Ombrófila Densa Submontana – no sopé da Serra do Mar, com cotas de altitude variando entre 50 e 500 m; 3) Floresta Ombrófila Densa Montana – recobrindo a encosta da Serra do Mar propriamente dita, em altitudes que variam de 500 a 1.200 m; 4) Floresta Ombrófila Densa Altimontana – ocorrendo no topo da Serra do Mar, acima dos limites estabelecidos para a formação montana, onde a vegetação praticamente deixa de ser arbórea, pois predominam os campos de altitude. Nas últimas três décadas muita informação vem sendo acumulada sobre a composição florística e a estrutura do estrato arbóreo dos remanescentes florestais do estado, conforme mostram as revisões de Oliveira-Filho & Fontes (2000) e Scudeller et al. (2001). Em florestas tropicais este tipo de informação, assim como dados sobre a riqueza de espécies, reflete não só fatores evolutivos e biogeográficos, como também o histórico de perturbação, natural ou antrópica, das respectivas áreas (Gentry 1992, Hubbell & Foster 1986). A síntese dessas informações tem permitido a definição de unidades fitogeográficas com diferentes padrões de riqueza de espécies e apontam para uma diferenciação, entre as florestas paulistas, no sentido leste/oeste (Salis et al. 1995, Torres et al. 1997, Santos et al. 1998). Segundo Bakker et al. (1996) um método adequado para acompanhar e avaliar as mudanças na composição das espécies e dinâmica da floresta ao longo do tempo é por meio de parcelas permanentes (em inglês Permanent Sample Plots –PSPs). Essa metodologia tem sido amplamente utilizada em estudos de longa duração em florestas tropicais, pois permite avaliar a composição e a estrutura florestal e monitorar sua mudança no tempo (Dallmeier 1992, Condit 1995, Sheil 1995, Malhi et al. 2002, Lewis et al. 2004). Permite avaliar também as consequências para a floresta de problemas como o aquecimento global e a poluição atmosférica (Bakker et al. 1996). No Brasil os projetos/programas que utilizam a metodologia de Parcelas Permanentes tiveram origem, praticamente, com o Projeto Rubiaceae (49) e Lauraceae (49) ao longo de todo gradiente da FOD e Monimiaceae (21) especificamente nas parcelas da FOD Montana. Em termos de número de indivíduos as famílias mais importantes foram Arecaceae, Rubiaceae, Myrtaceae, Sapotaceae, Lauraceae e na FOD Montana, Monimiaceae. Somente na parcela F, onde ocorreu exploração de madeira entre 1960 e 1985, a abundância de palmeiras foi substituída pelas Cyatheaceae. O gradiente estudado apresenta um pico da diversidade e riqueza nas altitudes intermediárias (300 a 400 m) ao longo da encosta (índice de Shannon-Weiner - H’ - variando de 3,96 a 4,48 nats.indivíduo–1). Diversas explicações para este resultado são apresentadas neste trabalho, incluindo o fato dessas altitudes estarem nos limites das expansões e retrações das diferentes fitofisionomias da FOD Atlântica durante as flutuações climáticas do Pleistoceno. Os dados aqui apresentados demonstram a extraordinária riqueza de espécies arbóreas da Floresta Ombrófila Densa Atlântica dos Núcleos Picinguaba e Santa Virgínia do Parque Estadual da Serra do Mar, reforçando a importância de sua conservação ao longo de todo o gradiente altitudinal. A diversidade desta floresta justifica também o investimento de longo prazo, através de parcelas permanentes, para compreender sua dinâmica e funcionamento, bem como monitorar o impacto das mudanças climáticas nessa vegetação.

Colonization of gastropods on subtidal reefs depends on density in adjacent habitats, not on disturbance regime

[EN] Habitats dominated by algal canopies are often altered by physical disturbances of varying severity, changing environmental conditions and biological processes. We used Artificial Seaweed Units (ASUs) to test whether severity of physical disturbances on algal canopies affects the post-disturbance colonization of gastropods on subtidal reefs. Specifically, we examined patterns of assemblage structure of gastropods to test the hypothesis that the extent and intensity of canopy removal affects the post-disturbance colonization of ASUs, testing the consistency of these effects among four regions encompassing a 68 latitudinal gradient in southwestern Australia. Because adjacent habitats can act as a source of new colonists (either as drifting migrants or as a source of propagules) from the perimeter surrounding perturbed areas, we also predicted that patterns of colonization (types and total abundances of colonizers) were influenced by the available pool of individuals at the scale of reefs. Three reefs were selected within each region. On each reef, ASUs were placed in the centre of circular canopy clearings of different size (0, 3, 13 and 50 m2) and intensity (50% vs 100%), and retrieved after 3 months. Resulting assemblages occupying the ASUs were quantitatively representative of the adjacent (undisturbed), algal-associated, assemblages at the scale of reef. Within reefs, recruited assemblages largely mimicked those associated with erect red algae. However, neither disturbance size nor intensity affected the colonization patterns across reefs and regions. These results suggest that algal-associated gastropods, regardless of the prevalent mode of dispersion, are resilient to physical disturbances to canopies across broad geographical regions as long as the pool of potential colonists is maintained. A high dispersal ability of gastropods likely ensures a quick colonization of recovering algal habitats.