Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri / A estrutura da planta determina a folhagem interceptada pela bromelia Tillandsiaturneri

Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.(AU)

As folhagens interceptadas pelas bromélias é um importante recurso para a comunidade de invertebrados, bactérias, fungos e para a própria planta. Estudou-se a relação entre a estrutura de 55 bromélias de Tillandsia tumeri, definida como o tamanho, a complexidade da planta, a folhagem acumulada por meio de regressão múltipla e o critério de informação de Akaike. Encontrou-se que as variáveis de tamanho, cobertura, comprimento da bainha e a variável de complexidade do número de folhas explicam a acumulação de folhas nas bromélias. Em conclusão, a estrutura do planta determina a quantidade de folhas armazenada na bromélia e os câmbios da estrutura da bromélia poderiam afetar importantes processos de funcionamento do ecossistema ou a riqueza de espécies.(AU)

Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

Abstract Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.

Resumo As folhagens interceptadas pelas bromélias é um importante recurso para a comunidade de invertebrados, bactérias, fungos e para a própria planta. Estudou-se a relação entre a estrutura de 55 bromélias de Tillandsia tumeri, definida como o tamanho, a complexidade da planta, a folhagem acumulada por meio de regressão múltipla e o critério de informação de Akaike. Encontrou-se que as variáveis de tamanho, cobertura, comprimento da bainha e a variável de complexidade do número de folhas explicam a acumulação de folhas nas bromélias. Em conclusão, a estrutura do planta determina a quantidade de folhas armazenada na bromélia e os câmbios da estrutura da bromélia poderiam afetar importantes processos de funcionamento do ecossistema ou a riqueza de espécies.

Termite assemblages (Blattodea: Isoptera) in a habitat humidity gradient in the semiarid region of northeastern Brazil

We compared the termite assemblages of different ecosystems in a humidity gradient. Three areas were sampled: (i) a humid montane forest; (ii) a hillside forest where shaded coffee (Coffea arabica Linnaeus, 1753) is cultivated; (iii) a seasonally dry forest (Caatinga). Active collection protocols were employed in each area during the dry and rainy seasons. The species were grouped according to their habitats and feeding habits. A total of 45 termite species belonging to 20 genera and three families were encountered. The termite fauna of the Caatinga was as rich and abundant as that of the humid forest areas, but it was distinct from it in species composition. Most termite species encountered in the montane forest were also found in the agro-ecological site, but some species were only found in the latter. The termite fauna of the Caatinga varied seasonally the most, with significantly reduced abundance during the dry period. When species richness, abundance, and species composition were considered together the climatic seasons were not found to significantly affect the termite faunas in any of the study areas. The numbers of encounters per feeding group and per habitat exploited did not differ among the different areas, or during the different seasons. Even in adjacent areas, the humidity gradient, as well as the vegetational characteristics, are reflected in differences in the termite fauna. Agro-ecological regimes can be considered viable alternatives to traditional methods of cultivation as they largely conserve the biodiversity found in non-modified environments.

Termite assemblages (Blattodea: Isoptera) in a habitat humidity gradient in the semiarid region of northeastern Brazil

We compared the termite assemblages of different ecosystems in a humidity gradient. Three areas were sampled: (i) a humid montane forest; (ii) a hillside forest where shaded coffee (Coffea arabica Linnaeus, 1753) is cultivated; (iii) a seasonally dry forest (Caatinga). Active collection protocols were employed in each area during the dry and rainy seasons. The species were grouped according to their habitats and feeding habits. A total of 45 termite species belonging to 20 genera and three families were encountered. The termite fauna of the Caatinga was as rich and abundant as that of the humid forest areas, but it was distinct from it in species composition. Most termite species encountered in the montane forest were also found in the agro-ecological site, but some species were only found in the latter. The termite fauna of the Caatinga varied seasonally the most, with significantly reduced abundance during the dry period. When species richness, abundance, and species composition were considered together the climatic seasons were not found to significantly affect the termite faunas in any of the study areas. The numbers of encounters per feeding group and per habitat exploited did not differ among the different areas, or during the different seasons. Even in adjacent areas, the humidity gradient, as well as the vegetational characteristics, are reflected in differences in the termite fauna. Agro-ecological regimes can be considered viable alternatives to traditional methods of cultivation as they largely conserve the biodiversity found in non-modified environments.(AU)

Leaf domatia in montane forest and Caatinga in the semiarid of Pernambuco State: Morphology and ecological implications / Domácias foliares em brejo de altitude e Caatinga no Semiárido pernambucano: morfologia e implicações ecológicas

Leaf domatia are cavity-shaped structures of different types or tufts of hairs located at the junction between ribs on the abaxial surface of the leaf blades of various families of angiosperms, serving as protection against phytophagous organisms by harboring beneficial mites, suggesting a mutualistic relationship. There is shortage of inventories of species with such structures; thus the present study examined native woody plant in two habitats of the backwoods of Pernambuco to identify the types of leaf domatia. 86 species were observed,43 inCaatinga area, out of which five had domatia, and43 inthe montane forest, 11 species with domatia. Four types of domatia were observed: hairtufts, pocket, pit and revolute margin. There was predominance of plant species with leaf domatia in the area Carro Quebrado in Triunfo,PernambucoState. These results corroborate the information available in the literature in which domatia are prevalent in more humid environments, and that these structures as micro-habitats influence the maintenance of diverse organisms.(AU)

Domلcias foliares sمo estruturas em forma de cavidades de diferentes tipos ou tufos de tricomas localizados na junçمo entre as nervuras, na face abaxial das lâminas foliares de diversas famيlias de angiospermas, servindo de defesa contra organismos fitَfagos por abrigarem لcaros benéficos, sugerindo uma relaçمo mutualيstica. Hل escassez de inventلrios de espécies apresentando essas estruturas; diante disso, o presente estudo analisou plantas lenhosas nativas em dois ambientes do sertمo de Pernambuco, visando identificar os tipos de domلcias foliares. Foram observadas 86 espécies, 43 em لrea de Caatinga em as quais cinco apresentaram domلcias e 43 no brejo de altitude, 11 espécies com domلcias. Foram encontrados quatro tipos de domلcias: tufo de pelos, bolso, cova e orla. Na لrea do Carro Quebrado, Triunfo, Estado do Pernambuco, as plantas com domلcias foliares foram predominantes. Estes resultados corroboram as informaçُes disponيveis na literatura de que domلcias sمo predominantes em ambientes mais ْmidos, e que essas estruturas como micro-habitats, influenciam a manutençمo de diversos organismos.(AU)

Taxonomy and biogeography of Stephanoxis Simon, 1897 (Aves: Trochilidae)

After the description in the 19th century of two hummingbird species currently allocated to the genus Stephanoxis, Peters (1945) merged both taxa into a single species without providing any rationale. Here we re-evaluate the taxonomy and species limits of the representatives of this genus based on an extensive number of specimens. We demonstrate these taxa are better treated as full species under both the Biological and Phylogenetic Species Concepts due to their well-defined range and plumage patterns and reciprocally diagnosability. They have distinct, allopatric distributions segregated by a 160 km gap between the Serra do Mar, to the east, and Serra de Paranapiacaba, to the west, in the state of São Paulo. Stephanoxis species have ranges which are congruent with other montane bird species’ suggesting shared vicariance events during preterit interglacial periods.

Taxonomy and biogeography of Stephanoxis Simon, 1897 (Aves: Trochilidae)

After the description in the 19th century of two hummingbird species currently allocated to the genus Stephanoxis, Peters (1945) merged both taxa into a single species without providing any rationale. Here we re-evaluate the taxonomy and species limits of the representatives of this genus based on an extensive number of specimens. We demonstrate these taxa are better treated as full species under both the Biological and Phylogenetic Species Concepts due to their well-defined range and plumage patterns and reciprocally diagnosability. They have distinct, allopatric distributions segregated by a 160 km gap between the Serra do Mar, to the east, and Serra de Paranapiacaba, to the west, in the state of São Paulo. Stephanoxis species have ranges which are congruent with other montane bird species suggesting shared vicariance events during preterit interglacial periods.(AU)