11 research outputs found
From wing to wing: the persistence of long ecological interaction chains in less-disturbed ecosystems
Human impact on biodiversity usually is measured by reduction in species abundance or richness. Just as important, but much more difficult to discern, is the anthropogenic elimination of ecological interactions. Here we report on the persistence of a long ecological interaction chain linking diverse food webs and habitats in the near-pristine portions of a remote Pacific atoll. Using biogeochemical assays, animal tracking, and field surveys we show that seabirds roosting on native trees fertilize soils, increasing coastal nutrients and the abundance of plankton, thus attracting manta rays to native forest coastlines. Partnered observations conducted in regions of this atoll where native trees have been replaced by human propagated palms reveal that this complex interaction chain linking trees to mantas readily breaks down. Taken together these findings provide a compelling example of how anthropogenic disturbance may be contributing to widespread reductions in ecological interaction chain length, thereby isolating and simplifying ecosystems
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Acoustic and camera surveys inform models of current and future vertebrate distributions in a changing desert ecosystem
Aim: Maintaining biodiversity in the face of land use and climate change is a paramount challenge, particularly when distributions of many species remain incompletely known. Emerging technologies help address this data deficiency by facilitating the collection of spatially explicit data for multiple species from multiple taxa. In this study, we combine acoustic and visual sensor surveys to inform conservation and land use planning in an area experiencing rapid climate and land use change. Location: Mojave Desert, California, United States. Methods: We deployed camera traps and acoustic detectors at 210 sites between March and July 2016. We identified photographic detections of mammals and acoustic recordings of songbirds to the species level and used multispecies occupancy models to estimate and evaluate species' occupancy probabilities. We then extrapolated model results to the region and forecasted how projected climate and land use changes might affect species' occupancy probabilities in 50 years. Lastly, we identified areas with high conservation value (i.e., high relative species richness) now and in 50 years, and related the distributions of these areas to land use designations. Results: We detected 15 mammal and 68 songbird species. At the community level, occupancy decreased with increasing temperatures and distances to woodlands. We forecasted that occupancy probabilities and areas with high conservation value would decline in 50 years due to projected increases in maximum temperatures and identified that up to 43%, 24% and 27% of land designated for renewable energy development, recreation and military activities, respectively, encompassed these high value areas. Main conclusions: Cooler areas close to woodlands and water are of high conservation value to mammals and songbirds in the Mojave. These areas will become increasingly limited with changing climate, however, making their protection from human disturbance imperative. We encourage continued use of visual and acoustic sensors across large spatial, temporal and taxonomic scales as tools to inform land use and wildlife conservation
Geomorphology and community structure of Middle Reef, central Great Barrier Reef, Australia: an inner-shelf turbid zone reef subject to episodic mortality events
Middle Reef is an inshore turbid zone reef located 4 km offshore from Townsville, Queensland, Australia. The reef consists of four current-aligned, interconnected reef patches that have reached sea level and formed reef flats. It is regularly exposed to high turbidity (up to 50 mg l-1) generated by wave-driven sediment resuspension or by episodic flood plumes. Middle Reef has a high mean hard coral cover (>39%), relatively low mean macro-algal cover (<15%) and a coral community comprising at least 81 hard coral species. Cluster analysis differentiated six benthic communities which were mapped onto the geomorphological structure of the reef to reveal a spatially patchy community mosaic that reflects hydrodynamic and sediment redistribution processes. Coral cover data collected annually from windward slope transects since 1993 show that coral cover has increased over the last ~15 years despite a history of episodic mortality events. Although episodic mortality may be interpreted as an indication of marginality, over decadal timescales, Middle Reef has recovered rapidly following mortality events and is clearly a resilient coral reef
division wise cumulative rainfall 01 June - 12 Sep 2017
Not AvailableProgress of Rainfall in Different Meteorological Sub-divisions of India (Relative departure from normal in %)
01 June - 12 Sep 2017Not Availabl
Water quality degradation of coastal waterways in the Wet Tropics, Australia
The Wet Tropics region of north Queensland has outstanding environmental values, contains the highest biological diversity in Australia, and borders the Great Barrier Reef. Comparable to other tropical areas worldwide, increasing urban and agricultural development in the Wet Tropics has caused concerns with respect to ecosystem degradation due to poor water quality in freshwater reaches and marine environments. Key issues currently identified in the Wet Tropics include erosion and subsequent stream turbidity and sedimentation, nutrients from erosion and fertiliser use and pesticide residue contamination. Issues such as reduced dissolved oxygen, acid sulfate soil runoff, and biological factors such as weed infestation, reduced and degraded riparian vegetation condition, and flow modification have also been identified. These issues mainly arise from agricultural activities with lesser effects from urban development. Management of pollution to improve in-stream water quality requires a long-term monitoring program to characterize water quality conditions over different flows and seasons. This type of monitoring program is underway; however, the focus is on the Great Barrier Reef and does not fully consider freshwater ecosystem health. Another major issue is the lack of a fully developed conceptual framework that links changed land use to water quality and subsequently to aquatic ecosystem health. In this paper, we establish the current level of water quality knowledge in the Wet Tropics while outlining a conceptual framework connecting changing land management practices and their effects to water quality and to ecosystem health