Maurício Bergamini Scheer

Florística vascular da Floresta Ombrófila Densa Altomontana de quatro serras no Paraná

A Floresta Ombrofila Densa Altomontana e uma formacao responsavel por importantes funcoes ambientais, entre elas a protecao e manutencao dos fluxos hidricos de cabeceiras de bacias hidrograficas, o estoque de carbono na sua biomassa e na do solo, alem da sua biodiversidade e seu elevado endemismo. Apesar de ainda existirem remanescentes primarios significativos dessas florestas, apenas alguns estudos descreveram sua estrutura arborea. O presente trabalho tem o objetivo de listar e comparar a floristica vascular de quatro serras representativas da Floresta Ombrofila Densa Altomontana no Parana e de comparar a floristica arborea das florestas do presente estudo com a de outras florestas semelhantes nas regioes sul e sudeste do Brasil. Foram detectadas 346 especies vegetais vasculares, pertencentes a 176 generos e a 87 familias, sendo 72 angiospermas (288 especies), 14 pteridofitas (57 especies) e 1 gimnosperma. A familia com maior riqueza especifica foi Myrtaceae, com 34 especies (10% do total), seguida por Asteraceae (30; 9%), Orchidaceae (29; 8%), Rubiaceae (17; 5%), Melastomataceae (16; 5%), Poaceae (12; 3%) e Bromeliaceae (11; 3%). A composicao floristica arborea das florestas altomontanas da Serra do Mar paranaense apresentou a menor similaridade entre as tres grandes serras comparadas, com indices um pouco maiores com as florestas altomontanas da regiao de Aparados da Serra Geral (SC) e menores com a Serra da Mantiqueira, sudeste do Brasil (SP, RJ e MG). Alem de diferencas geologicas, geomorfologicas, pedologicas e fitofisionomicas, as diferencas floristicas encontradas nas florestas altomontanas da Serra do Mar do Parana em relacao as demais serras comparadas pode tambem ser explicada pela melhor conservacao dos trechos amostrados e pela baixa influencia de elementos de outros tipos vegetacionais proximos (Floresta Ombrofila Mista, Floresta Ombrofila Densa Montana e vegetacao secundaria).

Estrutura arbórea da Floresta Ombrófila Densa Altomontana de serras do Sul do Brasil

The aims of this study were: (1) to group information about the tree structure of the upper montane rain forest of Serra do Mar in the state of Parana (PR), Southern Brazil; and (2) to compare this information with available data from other mountain ranges in Southern and Southeastern Brazil. In the four mountain ranges studied, 2294 tree individuals (perimeter at breast height - PBH > 10 cm) were sampled, which included 28 families, 43 genera and 78 species. The cloud forest sampled in Serra Gigante showed the highest richness (41 species), followed by Serra da Prata (37), Serra da Igreja (34) and Serra do Ibitiraquire (26). The mean tree height was 4.8 m, the PBH was 22.9 cm, the tree abundance was 4779 in/ha, the basal area was 33.5 m2/ha and the Shannon diversity index was 2.68 nats/ind. Combining our data with the published data on the Serra do Mar region, resulting in a total of 11 surveys and 204 plots (10200 m2), a matrix with 75 identified species was obtained. In this matrix, the five most important species in the structure of the forest were Ilex microdonta, Siphoneugena reitzii, Drimys angustifolia, Ocotea porosa and Ilex chamaedrifolia. The cloud forests sampled in Serra do Mar showed lower richness and diversity indexes than the cloud forests in Serra da Mantiqueira (Southeast) and higher richness and diversity than cloud forests in Aparados da Serra Geral (South). These differences are possibly related to the anthropic influences, geographic distances, different centers of endemism, the tropical and subtropical surroundings, and geomorphology, among other factors.

Funcionalidades ambientais de solos altomontanos na Serra da Igreja, Paraná

Apesar de ainda existirem ecossistemas altomontanos no Parana em excelente estado de conservacao, iminentes ameacas antropicas e a fragilidade desses ambientes tem sido motivos de preocupacao. Este trabalho teve os seguintes objetivos: caracterizar solos de area representativa dos campos e florestas altomontanas ocorrentes na Serra da Igreja; apontar quais os possiveis fatores pedologicos que resultam nessas diferentes fitotipias; e caracterizar algumas das suas funcionalidades ambientais (estoque de C e de agua). Os principais solos encontrados nos campos foram Organossolos Folicos fibricos/sapricos (liticos e tipicos) e Organossolos Haplicos fibricos/sapricos (tipicos e terricos) e, nas florestas altomontanas, Gleissolos Haplicos aliticos tipicos. Ambas as classes sao de solos distroficos, extremamente acidos, com alta saturacao por Al trocavel e altos teores de C orgânico total. A distribuicao das florestas altomontanas esta fortemente controlada por vales e colos de cumeeiras, os quais estao sujeitos a processos morfogeneticos que resultam em solos com horizontes minerais. Ja os campos estao estabelecidos em topos, onde processos pedogeneticos promoveram espessamento de horizontes histicos, os quais, em funcao de suas caracteristicas intrinsecas, aliadas aos fortes ventos, parecem conter com sucesso o avanco da floresta sobre o campo. Os estoques de C por unidade de area nos solos dos campos sao superiores aos dos solos das florestas altomontanas, sendo ambos considerados altos quando comparados aos dados de outros ecossistemas, sendo duas a tres vezes maiores do que os encontrados em solos de ecossistemas de altitudes mais baixas na mesma latitude. Tambem foi constatada alta capacidade de retencao hidrica devido a porosidade total verificada nos horizontes histicos, os quais tem o potencial de reter em media 12 vezes seu volume em agua.

Patterns of litter production in a secondary alluvial Atlantic Rain Forest in southern Brazil

Above-ground litter production is one of the most accessible ways to estimate ecosystem productivity, nutrient fluxes and carbon transfers. Phenological patterns and climatic conditions are still not fully explained well for tropical and subtropical forests under less pronounced dry season and non-seasonal climates, as well as the interaction of these patterns with successional dynamics. Monthly litterfall was estimated for two years in a 9 to 10 year old secondary alluvial Atlantic Rain forest. Total litterfall was higher in the site with more developed vegetation (6.4 ± 1.2 ton ha-1 year-1; 95% confidence interval) as compared to the site with less developed vegetation (3.0 ± 1.0 ton ha-1 year-1). The monthly production of 11 litter fractions (eight fractions comprising the leaf litter of the seven main species of the community and other species; reproductive parts, twigs £ 2 cm diameter, and miscellaneous material) were correlated with meteorological variables making possible to identify three patterns of deposition. The main pattern, dominated by leaf-exchanging species, consisted of a cycle with the highest litterfall at the beginning of the rainy season, preceding by basically three months the peaks of the annual cycles of rainfall and temperatures. Other two patterns, dominated by brevi-deciduous species, peaked at the end of the rainy season and at the end of the non-rainy season. Tropical and subtropical dry forests that present the highest leaf fall gradually earlier than rain forests (as the studied sites) are possibly related to the start of senescence process. It seems that such process is triggered earlier by a more severe hydric stress, besides other factors linked to a minor physiological activity of plants that result in abscission.

The Late Holocene upper montane cloud forest and high altitude grassland mosaic in the Serra da Igreja, Southern Brazil

Many soils of the highlands of Serra do Mar, as in other mountain ranges, have thick histic horizons that preserve high amounts of carbon. However, the age and constitution of the organic matter of these soils remain doubtful, with possible late Pleistocene or Holocene ages. This study was conducted in three profiles (two in grassland and one in forest) in Serra da Igreja highlands in the state of Paraná. We performed δ13C isotope analysis of organic matter in soil horizons to detect whether C3 or C4 plants dominated the past communities and 14C dating of the humin fraction to obtain the age of the studied horizons. C3 plants seem to have dominated the mountain ridges of Serra da Igreja since at least 3,000 years BP. Even though the Serra da Igreja may represents a landscape of high altitude grasslands in soils containing organic matter from the late Pleistocene, as reported elsewhere in Southern and Southeastern Brazil, our results indicate that the sites studied are at least from the beginning of the Late Holocene, when conditions of high moisture enabled the colonization/recolonization of the Serra da Igreja ridges by C3 plants. This is the period, often reported in the literature, when forests advanced onto grasslands and savannas.

Upper montane grassland structure within six subranges of Serra do Mar, Southern Brazil

The phytosociological structure of upper montane grasslands (high altitude grasslands) was studied in six subranges of Serra do Mar. Throughout 324 (1 m2) plot samples, we identified 195 taxa out of 280 taxa previously found in a floristic survey. Besides the general analysis of these communities, five physiognomies (synusiae) of these grasslands were previously determined based upon the species with greater cover. Cryptangium triquetrum and Croton mullerianus had the highest phytosociological importance value among the upper montane grasslands sampled in the present study. The first species was the most important of the grassy physiognomy of all sampled subranges and the second one of the shrubby physiognomy within three subranges. Chusquea pinifolia, Machaerina austrobrasiliensis, Deschampsia caespitosa, Gleichenella pectitata, Tibouchina dubia, Xyris stenophylla, Eryngium koehnearum and Eriochrysis holcoides were also structurally important. Although considerable species richness has been observed, the dominance of one or few species in the community was common in all subranges and physiognomies. In a brief comparison with upper montane vegetation studies (mainly on rocky outcrops) carried out in Southeastern Brazil, a low sharing of species was verified. Furthermore, the scarcity of studies in the literature regarding floristic and sociological structure of upper montane grasslands hampers a deeper analysis at level of species.