Spatial distribution patterns and their relations with environmental factors at different scales were identified in ca. 100-ha grassland under cattle and sheep grazing, in Eldorado do Sul, RS, Brazil (30 degrees 05'S, 51 degrees 40'W). The field survey used 138 0.5 x 0.5 m quadrats located systematically on transects along relief gradients. The quadrats were arranged in groups of 3 contiguous q...

Fire has become an increasingly important disturbance event in south-western Amazonia. We conducted the first assessment of the ecological impacts of these wildfires in 2008, sampling forest structure and biodiversity along twelve 500 m transects in the Chico Mendes Extractive Reserve, Acre, Brazil. Six transects were placed in unburned forests and six were in forests that burned during a serie...

In Shark Bay, Western Australia, bottlenose dolphins Tursiops sp. carry conical sponges Echinodictyum mesenterinum on their rostra in the only documented cetacean foraging behaviour using a tool (‘sponging’). In this study, we examined the influence of various ecological factors on live sponge distribution and the occurrence of sponging in parts of the western gulf of Shark Bay. We assessed spo...

Echinolaena inflexa (Poir.) Chase is an abundant C3 grass species with high biomass production in the Brazilian savanna (cerrado); Melinis minutiflora Beauv. is an African C4 forage grass widespread in cerrado and probably displacing some native herbaceous species. In the present work, we analysed seasonally the content and composition of soluble carbohydrates, the starch amounts and the above-...

The oviposition patterns of Aedes aegypti were investigated using modified ovitraps placed along 4 vertical transects and monitored weekly for 52 wk in St. Augustine, Trinidad, W.I. From the 832 ovitraps exposed at ground level, 1.2, 3.0 and 4.6-m elevations, 43% (361) were found containing 20,114 Ae. aegypti eggs. During the wet season, 52.7% of the eggs were collected whereas during the dry s...

Interrupting the processes which control ecosystem resources has dramatic impacts on the rangeland conditions. To protect ecosystems and landscape, it needs to understand the ecosystem processes which regulate the ecosystem resources. As main components of ecosystems, patches and inter-patches play important roles in energy and materials cascade. Ecologically, functional parameters such as stab...

Coral diseases have been reported as a major problem affecting Caribbean coral reefs. During August 2000, a coral mortality event of White Plague Disease-II (WPD-II) was observed at Madrizqui Reef in Los Roques National Park, Venezuela. This disease was identified as the major cause of coral mortality, affecting 24% of all colonies surveyed (n = 1 439). Other diseases such as Black Band Disease...

This study identifies and assesses the controls on hydraulic erosion of cohesive riverbanks on a 600-m reach of an urban ephemeral stream with active bank erosion. We examined hydraulic bank erosion by separating estimated bank shear stress into four properties: magnitude, duration, event peak, and variability. The values of these independent variables were used as a bank erosion context at thr...

during each event are also indicated. June 1982 to June 1983 (intense event, 1 transect); August 1986 to July 1987 (medium, 7 transects); October 1991 to May 1992 (marginal intensity, 2 transects); October 1992 to October 1993 (marginal, 3 transects); April 1994 to June 1995 (marginal, 8 transects); and April 1997 to April 1998 (intense, 15 transects). 12. To test biases caused by undersampling...

The northeastern Caribbean region experienced a record-breaking sea surface warming and prolonged mass bleaching during 2005. This event resulted in significant mortality of the principal Caribbean reef-building coral Montastraea annularis. We evaluated the demographics and size structure of a M. annularis population before, during, and after this event; stochastically simulated the population ...