Beta diversity patterns of Bromeliaceae growing on rocky cliffs within the Atlantic Forest in southern Brazil / Padrões de diversidade beta de Bromeliaceae crescendo em falésias rochosas dentro da Mata Atlântica no sul do Brasil

Abstract: In recent years there has been increasing attention in patterns of β-diversity and mechanisms related to variations in species composition. In this study, we evaluated beta diversity patterns of bromeliads growing on cliffs immersed in Atlantic Forest. We hypothesized that the species composition varies according to the spatial scale, inferring that there is a replacement of species influenced mainly by environmental factors. The study was carried out on sandstone cliffs included in contiguous but distinct vegetation formations: Evergreen and Seasonal forests. Twenty-four vertical rocky outcrops were sampled. The spatial variation in species composition was evaluated by two β-diversity components, turnover and nestedness. Multivariate analysis and variation partitioning were performed to distinguish niche and stochastic processes. We recorded 26 bromeliad species and a significantly higher contribution of turnover explaining beta diversity. Environmental factors affect β-diversity patterns of Bromeliaceae. However, individually, the environmental predictors do not explain the data variation. Environmental variations spatially structured, and spatial variables determinate the dissimilarity in the composition of bromeliads on cliffs. Thus, our results revealed that both environmental and spatial effects can act together to define the floristic composition of rock-dwelling bromeliad communities.

Resumo: Nos últimos anos tem havido uma crescente atenção em relação aos padrões de diversidade β e aos mecanismos relacionados às variações na composição de espécies. Neste estudo, nós avaliamos os padrões de diversidade beta de bromélias crescendo em escarpas rochosas imersas em matriz de Floresta Atlântica. Hipotetizamos que a composição das espécies varia de acordo com a escala espacial, inferindo que há uma substituição de espécies influenciadas principalmente por fatores ambientais. O estudo foi realizado em escarpas areníticas inseridas em formações vegetacionais contíguas, mas distintas: Florestas Ombrófila e Estacional. Vinte e quatro afloramentos rochosos verticais foram amostrados. A variação espacial na composição de espécies foi avaliada por dois componentes de diversidade β, turnover e aninhamento. Análise multivariada e particionamento da variação foram realizados para distinguir processos de nicho e estocásticos. Registramos 26 espécies de bromélias, com uma contribuição significativamente maior do turnover explicando a diversidade beta. Os fatores ambientais afetam os padrões de diversidade β de Bromeliaceae, no entanto, individualmente, esses preditores não explicam a variação dos dados. Assim, variações espaciais e variações ambientais espacialmente estruturadas determinam a dissimilaridade na composição de bromélias nas escarpas avaliadas. Desse modo, tanto os fatores ambientais determinísticos quanto os efeitos espaciais podem atuar em conjunto para definir a composição florística das comunidades de bromélias que se estabelecem sobre rochas.

Fine root growth and soil nutrient dynamics during shifting cultivation in tropical semi-evergreen forests of northeast India

Aim: The present study aimed to understand the periodical changes in fine root biomass, production, turnover and carbon and nitrogen return in forest fallows following shifting agriculture in Mizoram, Northeast India. Methodology: Root biomass was determined using sequential coring method in different fallow lands (FL-3, FL-5 and FL-10) following shifting agriculture. Annual fine root production was calculated as the sum of differences between annual maximum and minimum root biomass of different diameter classes. Concentrations of carbon and nitrogen in soil and roots were determined using CHN auto-analyzer, and their accumulations and returns were computed as the product of mass and element concentrations. Results: Total root biomass was maximum (561 g m-2) at FL-10, which decreased to 141 g m-2 at FL-3 with greater accumulation of fine roots in upper soil layer (0-10 cm) and coarse roots in lower depths. Root biomass was maximum (1499 g m-2) at the time of slashing which decreased to about one fourth just after burning. The amount of organic matter, carbon and nitrogen return to soil through fine root death was significantly regulated by soil moisture, microbial biomass carbon and total nitrogen in different fallow lands. Interpretation: Addition of organic matter, carbon and nitrogen to soil through death and decomposition of fine roots is an important mechanism responsible for sustaining soil fertility and crop productivity in different fallow lands. The output of the study has implications for the management of fallow lands following shifting cultivation and modeling global cycles of carbon and nitrogen.

Environmental drivers on leaf phenology of ironstone outcrops species under seasonal climate

ABSTRACT Banded iron formations (BIF) have a particular vegetation type and provide a good model system for testing theories related to leaf phenology, due to unique stressful environmental conditions. As a consequence of the stressful conditions of BIF environment, we hypothesize that most species would retain at least some significant canopy cover, even at the end of the dry season, independently of growth form - trees, shrubs, and sub-shrubs. Considering the strong seasonality, we also hypothesize that photoperiod and rainfall act as triggers for leaf fall and leaf flushing in these environments. The majority of the fifteen studied species had a semi-deciduous behavior and shed their leaves mainly during the dry season, with a recovery at the end of this season. In general, leaf flushing increased around the spring equinox (end of the dry season and start of the rainy season). A trade-off between leaf loss and leaf maintenance is expected in a community in which most plants are naturally selected to be semi-deciduous. Our results suggest photoperiod as a dominant factor in predicting leaf phenology.

Una nueva subespecie de Heraclides androgeus (Lepidoptera: Papilionidae) y sus aspectos biogeográficos / A new subspecies of Heraclides androgeus (Lepidoptera: Papilionidae) and its biogeographical aspects

Heraclides androgeus epidaurus was described and illustrated by Godman & Salvin in 1890 based on specimens obtained in Veracruz, indicating that their distribution encompassed both the Pacific and Atlantic sides of Mexico. Later authors commented that there were morphological differences between the male wings from both populations. We analyzed, described and nominated Heraclides androgeus reyesorum ssp. nov. Vargas, Llorente & Luis distributed in the Mexican Pacific coast, based on 62 specimens, and compared it with H. a. epidaurus from the Gulf of Mexico, based on more than 200 specimens housed at UNAM: Museo de Zoología, Facultad de Ciencias and the Colección Nacional de Insectos of the Instituto de Biología, as well as some collections from the USA. The main characters were the width of the yellow and black bands on forewings in males, which had a significant difference between the populations of both sides of Mexico, although some characters were variable and showed partial overlap. In the hindwings, the differences were the extent of the subterminal lunules in dorsal and ventral view. We also analyzed the male genitalia, finding notorious differences in both sclerotic processes of the harpe. Subspecific differences between females refer to the brightness and extent of green spots on the hindwings and the extent of lunules in the ventral view. The greatest abundance of H. a. reyesorum ssp. nov. was in the tropical deciduous forest, with gallery forest and in the lower range of the cloud forest, present at altitudes of 500-800m and 1 000-1 750m, respectively. We discussed the pattern of endemism due to historical vicariant processes and explain the presence of the new subspecies of H. androgeus and other taxa of specific level.

Hemos reunido evidencia de que Heraclides está formado por dos subespecies, cada una con caracteres propios que las distinguen; analizamos, describimos y nominamos a Heraclides androgeus reyesorum ssp. nov. que se distribuye en la costa pacífica mexicana. Los principales caracteres masculinos fueron la amplitud de las bandas amarilla y negra en alas anteriores, que al cuantificarse y analizarse tuvieron una diferencia significativa entre las poblaciones de las dos vertientes de México, a pesar que algunos caracteres son variables y muestran superposición parcial. En alas posteriores las diferencias fueron la amplitud de lúnulas subterminales en vista dorsal y ventral. Se analizaron los genitales masculinos, se encontraron diferencias determinantes en los procesos esclerosados del harpagón. Las diferencias subespecíficas entre hembras se refieren al brillo y extensión de las manchas verdes en alas posteriores y a la amplitud de lúnulas en vista ventral. La mayor abundancia de H. a. reyesorum ssp. nov. fue en el bosque de galería del bosque tropical caducifolio y en el intervalo inferior del bosque mesófilo, a 500-800m y 1 000-1 750m, respectivamente. Se discute la existencia de un patrón de endemismo analizado por Halffter (1978) y Morrone & Llorente (2006) que obedece a procesos históricos vicariantes y resume la presencia de subespecies nuevas en el Pacífico como en H. androgeus y muchos otros taxones.

Aspectos florísticos e fitossociológicos de um trecho de Floresta Estacional Perenifólia na Fazenda Trairão, Bacia do rio das Pacas, Querência-MT / Floristic and phytosociological aspects of a Seasonal Evergreen Forest area in the Trairão Farm, rio das Pacas Basin, Querência-MT

A borda sul da região amazônica apresenta um tipo peculiar de floresta, denominada de Floresta Estacional Perenifólia, que atualmente vem sofrendo severos impactos ambientais devido à expansão da fronteira agrícola no Norte do Estado de Mato Grosso. Diante da falta de estudos neste tipo florestal, objetivou-se identificar a composição florística e a estrutura fitossociológica do componente arbóreo de um trecho florestal na Fazenda Trairão em Querência-MT. A amostragem da vegetação consistiu na distribuição de 200 pontos-quadrantes, sendo considerados os quatro indivíduos mais próximos de cada ponto que tivessem DAP (diâmetro à altura do peito) igual ou superior a 10 cm. A densidade total foi de 728 ind./ha, distribuídos em 49 espécies, 39 gêneros e 24 famílias. A família que apresentou maior riqueza foi Fabaceae (cinco espécies), seguida por Burseraceae e Euphorbiaceae, cada uma com quatro espécies, consideradas também as mais ricas em trechos de Floresta Amazônica. As espécies de maior Valor de Importância (VI) foram Ocotea leucoxylon (Sw.) Laness., Xylopia amazonica R.E. Fr., Myrcia multiflora (Lam.) DC., Chaetocarpus echinocarpus (Baill.) Ducke e Protium pilosissimum Engl., mas não tiveram a mesma representatividade em outros trechos de Floresta Estacional Perenifólia, evidenciando diferenças estruturais desta unidade fitogeográfica. A comunidade avaliada possui porte fino, pois a maioria dos indivíduos concentra-se nas classes de diâmetro entre 10 e 14,9 cm e altura entre 10,6 e 16,5 m. O índice de Shannon (3,17) é considerado baixo por se tratar de floresta amazônica, na qual a diversidade é superior a 4,0.

The southern border of the Amazon region presents a peculiar type of forest called Seasonal Evergreen Forest, which has currently undergone several environmental impacts due to the agriculture frontier expansion from the Northern state of Mato Grosso. Due to the lack of studies on this type of forest, the objective of this study was to identify the floristic composition and phytosociological structure of the arborous component from a forest area in the Trairão Farm, Querência - MT, Brazil. The vegetation sampling was composed of the distribution of 200 quadrant-points in which the four individuals closest to each point, with DAP (diameter to height breast) equal or superior to 10 cm were considered. The total density of the sampled area was 728 ind./ha distributed into 49 species, 39 genera and 24 families. The species presenting the highest richness was Fabaceae (five species), followed by Burseraceae and Euphorbiaceae, with four species each, and considered as the richest in some Amazon forest areas. The species of highest Importance Value (IV) were Ocotea leucoxylon (Sw.) Laness., Xylopia amazonica R.E. Fr. and Myrcia multiflora (Lam.) DC., Chaetocarpus echinocarpus (Baill.) Ducke and Protium pilosissimum Engl., but did not present the same representativity as in other Seasonal Evergreen Forest area, evidencing structural differences within this phytogeographic unit. The majority of individuals from this community present slender size, with diameter ranging from 10 to 14.9 cm and height from 10.6 to 16.5 m. The Shannon index (3.17) may be considered as low in relation to the Amazon Forest in which the diversity is above 4.0.

Factors influencing seasonal and monthly changes in the group size of chital or axis deer in southern India.

Chital or axis deer (Axis axis) form fluid groups that change in size temporally and in relation to habitat. Predictions of hypotheses relating animal density, rainfall, habitat structure, and breeding seasonality, to changes in chital group size were assessed simultaneously using multiple regression models of monthly data collected over a 2 yr period in Guindy National Park, in southern India. Over 2,700 detections of chital groups were made during four seasons in three habitats (forest, scrubland and grassland). In scrubland and grassland, chital group size was positively related to animal density, which increased with rainfall. This suggests that in these habitats, chital density increases in relation to food availability, and group sizes increase due to higher encounter rate and fusion of groups. The density of chital in forest was inversely related to rainfall, but positively to the number of fruiting tree species and availability of fallen litter, their forage in this habitat. There was little change in mean group size in the forest, although chital density more than doubled during the dry season and summer. Dispersion of food items or the closed nature of the forest may preclude formation of larger groups. At low densities, group sizes in all three habitats were similar. Group sizes increased with chital density in scrubland and grassland, but more rapidly in the latter–leading to a positive relationship between openness and mean group size at higher densities. It is not clear, however, that this relationship is solely because of the influence of habitat structure. The rutting index (monthly percentage of adult males in hard antler) was positively related to mean group size in forest and scrubland, probably reflecting the increase in group size due to solitary males joining with females during the rut. The fission-fusion system of group formation in chital is thus interactively influenced by several factors. Aspects that need further study, such as interannual variability, are highlighted.

Fine root dynamics in two tropical dry evergreen forests in southern India.

Seasonality in fine root standing crop and production was studied in two tropical dry evergreen forests viz., Marakkanam reserve forest (MRF) and Puthupet sacred grove (PSG) in the Coromandel coast of India. The study extended from December 89 to December 91 in MRF and from August 90 to December 91 in PSG with sampling at every 2 months. Total fine interval. Mean fine root standing crop was 134 g m-2 in MRF and 234 g m-2 in PSG. root production was 104 g m-2 yr-l in MRF and 117 g m-2 yr-1 in PSG. These estimates lie within the range for fine roots reported for various tropical forests. Rootmass showed a pronounced seasonal pattern with unimodal peaks obtained during December in the first year and from October-December in the second year in MRF. In PSG greater rootmass was noticed from June-October than other times of sampling. The total root mass in MRF ranged from 114 to 145 g m-2 at the 13 sampling dates in the three sites. The live biomass fraction of fine roots in MRF ranged from 46 to 203 g m–2 and in PSG it ranged from 141 to 359 g mm –2 during the study periods. The dead necromass fraction of fine roots ranged from 6 to 37 g m-2 in MRF and from 12 to 66 g m-2 in PSG. Fine root production peaked during December in both the forest sites. The necromass fraction of newly produced roots was negligible. Total Ν was slightly greater in PSG than in MRF. Whereas total Ρ level was almost similar in both the sites. The study revealed that season and site characteristics influenced fine root system.