Aeropalynology of Australian native arboreal species in Brisbane, Australia

The influence of meteorological parameters on airborne pollen of Australian native arboreal species was investigated in the sub-tropical city of Brisbane, Australia over the five-year period, June 1994–May 1999. Australian native arboreal pollen (ANAP), shed by taxa belonging to the families Cupressaceae, Casuarinaceae and Myrtaceae accounts for 18.4% of the total annual pollen count and is distributed in the atmosphere during the entire year with maximum loads restricted to the months May through November. Daily counts within the range 11–100 grains m–3 occurred over short intervals each year and were recorded on 100 days during the five-year sampling period. Total seasonal ANAP concentrations varied each year, with highest annual values measured for the family Cupressaceae, for which greater seasonal frequencies were shown to be related to pre-seasonal precipitation (r 2 = 0.76, p = 0.05). Seasonal start dates were near consistent for the Cupressaceae and Casuarinaceae. Myrtaceae start dates were variable and established to be directly related to lower average pre-seasonal maximum temperature (r 2 = 0.78, p = 0.04). Associations between daily ANAP loads and weather parameters showed that densities of airborne Cupressaceae and Casuarinaceae pollen were negatively correlated with maximum temperature (p < 0.0001), minimum temperature (p < 0.0001) and precipitation (p < 0.05), whereas associations with daily Myrtaceae pollen counts were not statistically significant. This is the first study to be conducted in Australia that has assessed the relationships between weather parameters and the airborne distribution of pollen emitted by Australian native arboreal species. Pollen shed by Australian native Cupressaceae, Casuarinaceae and Myrtaceae species are considered to be important aeroallergens overseas, however their significance as a sensitising source in Australia remains unclear and requires further investigation.

Species diversity and dominance-richness relationships for ground and arboreal ant (Hymenoptera: Formicidae) assemblages in Namibian desert, saltpan, and savannah

Namibia has high levels of invertebrate endemism, but biodiversity research has been geographically and taxonomically limited. In South African savannah, species richness of ground-foraging ant assemblages is regulated by dominant ant species, but this pattern has not been tested in other arid environments. In this study, we provide a description of ant diversity at baits in three different Namibian habitats (savannah, saltpan and desert), and we test the relationship between ant dominance and richness for ground-foraging and arboreal species. Forty-two ant species were collected in this study, with species richness being highest in the saltpan, followed by savannah and then desert. Ant assemblages were most similar between the savannah and desert, due to shared arboreal species. Similarity between savannah and saltpan ant assemblages was due to an overlap in ground-foraging species. Ground ants were more diverse than arboreal ants, and several species were observed at baits for both strata, although the degree of overlap varied with habitat type. The dominance-richness relationship varied depending on habitat and sampling strata. We found a unimodal relationship in the saltpan, but not in the savannah. For ground ants the relationship was logarithmic, with increasing abundance of dominants leading to decreasing overall species richness. However, no trend was observed for the arboreal ant assemblage. In the desert, low ant abundance meant that we were unable to assign species dominance, possibly due to reduced foraging activity caused by high temperatures. The lack of a consistent dominance-richness trend across assemblages may be the result of varying degrees of environmental stress or competition. Our study is a preliminary description of diversity and dominance in Namibia, and we hope it stimulates further research on ant assemblages in arid regions of Africa.

Morphological adaptations to arboreal habitats and heart position in species of the neotropical whipsnakes genus Chironius

The evolution of arboreality in snakes is accompanied by modifications that are remarkably similar across species. Gravity is one of the most important selective agents, and arboreal snakes present adaptations to circumvent the gradient of pressure, including modifications on heart position (HP) and body slenderness (BS). However, the degree to which different life-history traits influence the cardiovascular system of snakes remains unclear. Here, we used an ecological and a phylogenetic approach to explore the relationship between habitat, HP, BS, and heart size (HS) in five species of the neotropical whipsnakes genus Chironius that occupy terrestrial, semiarboreal, and arboreal habits. Our ecological comparison indicated that the arboreal species have the most posterior-positioned heart, the most slender body, and the smallest HS, whereas the terrestrial representative of the group exhibited the most anterior heart, the less flattened body, and the largest HS. After removing the phylogenetic effect, we found no difference in HP and BS between terrestrial and arboreal species. Habitat only differed when contrasting with HS. Body slenderness and HS were correlated with HP. Our results suggest that different restrictions, such as anatomical constraints, behavior, and phylogenetic inertia, may be important for the studied species. © 2013 The Royal Swedish Academy of Sciences.

Influence de la locomotion sur la morphologie de l’articulation distale de l’humérus chez les hominoïdes

La masse corporelle et la direction des charges sont des facteurs qui peuvent modifier la morphologie des surfaces articulaires qui sont généralement orientées et de taille suffisante pour résister aux charges chroniques. Chez les hominoïdes, les forces de tension et compression, générées par la locomotion, sont transmises à travers l’articulation du coude. Ces espèces ont une morphologie similaire de l’extrémité distale de l’humérus, mais qui présente certaines différences selon la taille des individus et leurs modes de locomotion. Ce projet tente de caractériser plus exhaustivement cette variation en analysant la largeur des surfaces articulaires ainsi que leur position et orientation par rapport à l’axe long de la diaphyse. La prémisse de ce mémoire est que, chez les espèces plus arboricoles, la morphologie de l’articulation distale de l’humérus répond aux stress transverses générés par les puissants muscles fléchisseurs du poignet et des doigts qui traversent le coude obliquement. En revanche, les espèces plus terrestres présentent une morphologie permettant de résister aux forces axiales provenant du contact avec le sol. Des coordonnées tridimensionnelles et des mesures linéaires ont été recueillies sur un échantillon squelettique d’individus des genres Homo, Pan, Gorilla et Pongo. Les résultats obtenus révèlent que l’orientation et la position des surfaces articulaires de la trochlée correspondent aux types de locomotion, or leur taille et celle et du capitulum semblent être influencées par la taille des individus. L’hypothèse suggérant que les stress reliés aux divers modes de locomotion des hominoïdes influencent la morphologie de l’articulation distale de l’humérus est donc supportée.

L’orientation de la cavité glénoïde de la scapula chez les grands singes (Gorilla, Pan et Pongo) et l’humain moderne : une étude comparative et ontogénique

Le degré de rétention de l’arboricolisme dans le répertoire locomoteur des hominines fossiles du Pliocène est toujours matière à débat, les études ayant principalement porté sur la courbure des phalanges et la proportion des membres. Vu la récente découverte de DIK-1-1 (A. afarensis) et de la scapula qui lui est associée, l’étude de cet os d’un point de vue fonctionnel est intéressante, puisqu’il est directement impliqué dans la locomotion de presque tous les hominoïdes. Le but de cette étude est de tenter d’établir un lien entre l’orientation supéro-inférieure (SI) et antéro-postérieure (AP) de la cavité glénoïde de la scapula et les comportements locomoteurs chez les grands singes et l’humain moderne. Des analyses comparatives sur les adultes ont été réalisées pour 1) voir s’il existe des différences dans la morphologie étudiée entre les espèces et 2) voir si ces différences peuvent être expliquées par la taille corporelle. Des analyses ontogéniques ont aussi été réalisées pour voir si un accroissement de la taille corporelle pendant le développement et les changements locomoteurs qui y sont associés correspondent à un changement d’orientation de la cavité glénoïde. Les résultats montrent que les humains ont une cavité glénoïde qui est orientée moins supérieurement que les grands singes, mais que Pongo, bien qu’étant le plus arboricole, n’a pas l’orientation la plus supérieure. Les « knuckle-walkers » (Pan et Gorilla) se distinguent des autres hominoïdes avec une orientation de la surface glénoïde relative à l’épine plus inférieure. La taille corporelle ne semble pas influencer la morphologie étudiée, sauf parfois chez le gorille. Seuls l’humain et les mâles Pongo montrent un changement ontogénique dans l’orientation de la cavité glénoïde relativement à l’épine. Sur la base de ces résultats, l’orientation de la cavité glénoïde semble refléter partiellement la fonction du membre supérieur dans la locomotion, mais des recherches plus poussées sont nécessaires. Mots-Clés : Scapula, cavité glénoïde, grands singes, humains, locomotion, arboricolisme.

The evolution of jumping performance in anurans: morphological correlates and ecological implications

We investigated the evolution of anuran locomotor performance and its morphological correlates as a function of habitat use and lifestyles. We reanalysed a subset of the data reported by Zug (Smithson. Contrib. Zool. 1978; 276: 1-31) employing phylogenetically explicit statistical methods (n = 56 species), and assembled morphological data on the ratio between hind-limb length and snout-vent length (SVL) from the literature and museum specimens for a large subgroup of the species from the original paper (n = 43 species). Analyses using independent contrasts revealed that classifying anurans into terrestrial, semi-aquatic, and arboreal categories cannot distinguish between the effects of phylogeny and ecological diversification in anuran locomotor performance. However, a more refined classification subdividing terrestrial species into `fossorials` and `non-fossorials`, and arboreal species into `open canopy`, `low canopy` and `high canopy`, suggests that part of the variation in locomotor performance and in hind-limb morphology can be attributed to ecological diversification. In particular, fossorial species had significantly lower jumping performances and shorter hind limbs than other species after controlling for SVL, illustrating how the trade-off between burrowing efficiency and jumping performance has resulted in morphological specialization in this group.

Composição florística de remanescente de cerrado sensu stricto em Botucatu, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The evolution of jumping performance in anurans: morphological correlates and ecological implications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Distribuição espacial em pequena escala de um anfípode exótico em fragmento florestal e plantio de espécies nativas

Anthropogenic interferences in natural environments cause the breakage of spatial and competitive barriers, which may infuence the spatial distribution of species. In this study, we describe the spatial distribution of an exotic amphipod, Talitroides topitotum, in two distinct sites, a forest fragment and a plantation of native arboreal species. We analyzed possible variations in this spatial distribution in different periods of the year and verifed whether the vegetation cover and the litter layer depth may explain the distribution pattern of this species. We performed analyses of frequency distribution to determine the pattern of this species spatial distribution, as well as correlation tests to determine the effect of these two variables of habitat structure. The spatial distribution analysis revealed that T. topitotum presents aggregated distribution in both areas, indicating that this species has low environmental demands or that both areas are below a minimum environmental quality threshold. However, even with this similarity, the population in the fragmented site presented a higher index of aggregation when compared with the population of the plantation site. Corroborating previous studies, there was a negative correlation between abundance of T. topitotum and litter layer depth in the plantation site. Studies on invaded habitats can help understand how invasive species occupy new environments and the factors that can infuence their spatial distribution.

Phylogeny, Ecology, and Heart Position in Snakes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Regeneração natural em remanescentes florestais e áreas reflorestadas da várzea do rio Mogi-Guaçu, Luiz Antônio - SP

O trabalho objetivou descrever e avaliar a estrutura da regeneração de espécies arbóreas em dois remanescentes naturais e em três áreas reflorestadas com espécies nativas e em um povoamento de Eucalyptus robusta, situados em área de várzea do rio Mogi-Guaçu, Luiz Antônio, SP (21º31'S e 47º55'W). Foram amostradas 40 subparcelas de 2 m² em cada remanescente natural e sub-bosque de eucalipto e 60 subparcelas de 3,5 m² em cada área reflorestada. Foram amostrados todos os indivíduos arbóreos de regeneração com altura > a 10 cm e diâmetro do caule até a altura do peito (DAP) < 5,0 cm e analisados separadamente, em quatro classes de altura, a diversidade florística, a regeneração natural (Rn%), o valor de importância (VI) e a similaridade da regeneração com indivíduos de DAP > 5 cm. Foram identificados 1.990 indivíduos, pertencentes a 24 famílias, 46 gêneros e 51 espécies. Cabralea canjerana, Psidium cattleyanum, Nectandra megapotamica, Acacia polyphylla e Syzygium cumini estavam entre as espécies mais representadas nas quatro categorias de tamanho. O reflorestamento com espécies nativas em áreas degradadas da várzea do rio Mogi-Guaçu promoveu a regeneração natural com biodiversidade superior aos remanescentes naturais de florestas ciliares sob efeito de borda e contribuiu para com o processo de restauração de ecossistemas florestais. O povoamento de Eucalyptus robusta com cerca de 20 anos de idade favoreceu a regeneração de espécies climácicas e secundárias.

Banco de sementes de remanescentes naturais e de áreas reflorestadas em uma várzea do Rio Mogi-Guaçu - SP

Este estudo avaliou qualitativa e quantitativamente o banco de sementes de dois remanescentes florestais, de um povoamento de Eucalyptus robusta e de três áreas de reflorestamento com espécies nativas, localizados em uma várzea do rio Mogi-Guaçu, Luiz Antônio (21°31´S e 47°55´W), Estado de São Paulo, Brasil. Foram usadas 12 parcelas de 10 x 10 m distribuídas sistematicamente em cada área de estudo. em cada parcela foram distribuídas aleatoriamente quatro subparcelas de 0,5 m x 0,5 m. Duas subparcelas foram usadas para coletar a serapilheira e duas para coletar o solo a 0-5 cm de profundidade. A amostragem foi realizada em setembro de 2001, nos remanescentes naturais e no povoamento de eucalipto e, em setembro de 2002, nas áreas reflorestadas. As amostras foram acondicionadas em vasos de plástico e incubadas com irrigações periódicas para a germinação das sementes por um período de sete meses, em dois ambientes de casa de vegetação: um a 100% de luz solar e outro sob tela com 70% de redução de luz solar. Na composição do banco de sementes de todas as áreas amostradas, houve predominância de espécies pioneiras dos primeiros estádios de sucessão. As espécies arbóreas mais importantes foram Aloysia virgata e Cecropia hololeuca. Os reflorestamentos com espécies nativas proporcionaram um banco de sementes com maior diversidade de espécies arbóreas nativas do que o povoamento de eucalipto. Este estudo indicou que a similaridade entre as florestas plantadas e as nativas deverá aumentar ao longo do tempo.

Caracterização citogenética em Anadenanthera colubrina (Vell.) Brenan (Mimosoideae) e Guazuma ulmifolia Lam. (Sterculiaceae)

Análises cariotípicas são importantes ferramentas de auxílio aos estudos de relações taxonômicas dentro dos grupos vegetais. Espécies arbóreas nativas encontradas no cerrado brasileiro têm sido pouco analisadas do ponto de vista citogenético e citotaxonômico. Com o objetivo de determinar o número cromossômico diplóide, a biometria e a morfologia cromossômica de Anadenanthera colubrina (angico-branco) e Guazuma ulmifolia (mutambo), sementes dessas espécies foram coletadas no município de Três Lagoas, Mato Grosso do Sul, Brasil. A utilização de 8-hidroxiquinoleína 0,003M a 36ºC, durante três horas possibilitou a separação cromossômica. Coloração Giemsa 2% por três minutos permitiu o estudo cariológico. A classificação cromossômica foi baseada no índice centromérico. Anadenanthera colubrina possui 2n = 26 cromossomos com comprimento cromossômico médio de 1,349 µm ± 0,017 e formulação cariotípica 8SM + 14M + 2T + 2AC. Guazuma ulmifolia apresenta 2n = 16 cromossomos com comprimento médio de 1,225 µm ± 0,023 e formulação cariotípica 4SM + 10M + 2T. Esses resultados podem subsidiar estudos de taxonomia, de manipulação cromossômica, bem como auxiliar na produção de progênies híbridas em programas de melhoramento.

Aspectos morfológicos de frutos, sementes, germinação e plântulas de Hymenolobium petraeum

Hymenolobium petraeum Ducke é uma espécie arbórea pertencente à família Leguminosae conhecida popularmente por angelim-pedra. Apresenta alto valor comercial, com madeira muito utilizada na construção civil e marcenaria. Este trabalho teve por objetivo descrever morfologicamente o fruto, a semente e as plântulas, assim como, determinar as temperaturas cardeais para a germinação de sementes de angelim-pedra. Foram determinados o comprimento, a largura e a massa fresca de frutos e sementes. Para os testes de germinação foram utilizadas três repetições de 50 sementes, colocadas em placas de Petri e mantidas em germinadores nas temperaturas de 15, 20, 25, 30, 35 e 40°C e fotoperíodo de 12 horas. Os frutos são legumes-samaróides, indeiscentes, oblongos e unicarpelares. As sementes são de coloração castanho-escura, oblongas, estenospérmicas, exalbuminosas e com plúmula inconspícua. A raiz primária é branca e pubescente na região próxima ao colo; a parte aérea das plântulas possui pilosidade branca, protófilos compostos imparipinados e com inserção oposta, epicótilo verde, ereto, cilíndrico e piloso e os metáfilos imparipinados e com inserção alterna-espiralada. A germinação é semi-hipógea criptocotiledonar. Para de sementes de angelim-pedra as temperaturas máximas de germinação estão acima de 35°C e a mínima abaixo de 15°C, enquanto a faixa de temperatura ótima para germinação está entre 25 e 35°C.

Germination and anaerobic metabolism of seeds of Tabebuia cassinoides (Lam.) DC subjected to flooding and anoxia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)