How old is the australian wet tropics?5 answersThe Australian Wet Tropics region has a rich history dating back to significant geological timescales. The area provides a detailed record of terrestrial environmental responses over the last 250,000 years, with a new chronology established for the last 60,000 years based on radiocarbon dating. This region, stretching along the northeast coast of Australia for 450 km, contains relicts of ancient Gondwanan forests that existed 50-100 million years ago, contributing to the evolution of Australia's flora and fauna. The Wet Tropics have acted as a museum of biological diversity, with diversification in endemic earthworms dating back to the Paleogene era. The region's environmental changes have been studied over the last 30,000 years, showing synchronous fluvial responses to climate shifts at various intervals. The Wet Tropics of northern Queensland, covering less than 1% of Queensland, were granted World Heritage status in 1988, emphasizing the region's ecological significance.
What are the long-term effects of the Murray-Darling Basin Plan on Australian irrigated cropping?4 answersThe Murray-Darling Basin Plan has significant implications for Australian irrigated cropping. The Plan, initiated in 2012 with a focus on returning water to the environment, faces challenges in meeting its targets due to policy adjustments and climate change impacts. The Basin's warming climate and increased water demand from various sectors pose a threat to water availability for agriculture, potentially leading to reduced farm output. The historical development of the Basin for agriculture, coupled with recent water reforms reallocating water to the environment, has altered patterns of irrigated agriculture and added pressure on rural communities. The shift from buybacks to infrastructure upgrades and the economic impacts on farmers highlight the complexities of balancing water use between irrigation and environmental needs.
How important are birds in the Australian wet tropics?4 answersBirds play a crucial role in the Australian wet tropics. The wet sclerophyll forest, a unique and threatened ecosystem in the region, supports a high diversity of bird species, including many endemics. Birds in this ecosystem have specific foraging guilds, such as insect-eaters and nectar-feeders, which contribute to the trophic structure of the forest. However, the wet tropics are facing significant challenges due to climate change. Montane bird populations in the Australian Wet Tropics World Heritage Area have experienced declines in local abundance and distribution, particularly for upland-specialized species and regional endemics. Additionally, changes in fire regime have led to the loss of wet sclerophyll forest, impacting bird populations that depend on this habitat. To maintain the full range of biodiversity in the wet tropics, it is essential to conserve and manage the wet sclerophyll forest and its dependent bird species.
What is the environmental impact of water lilies?4 answersWater lilies have both positive and negative environmental impacts. On the positive side, conditioned and treated water lilies can be used to manage liquid and semi-liquid waste, reducing environmental liability and generating alternative energy. Water lilies also have the potential to enhance greenery and beautify landscapes in arid climates like Kuwait. Additionally, tropical water lilies have been found to remove hexavalent chromium from aqueous solutions, indicating their potential for bioremediation. On the negative side, water lilies, such as water hyacinth, can negatively affect freshwater ecosystems by reducing underwater light intensity and hindering air exchange, which can impact the structure of aquatic animal and plant communities. Overall, the environmental impact of water lilies depends on their specific use and context.
What are the most significant environmental challenges facing the Murray-Darling basin?5 answersThe most significant environmental challenges facing the Murray-Darling Basin include water security, water quality, groundwater depletion and degradation, and the impact of climate change. Historically, the focus has been on water security and allocation of water for competing needs, with water quality being secondary. However, there is a need to reframe water quality as an integral component of the risks to shared water in the Basin. The assessment of risks to groundwater resources and groundwater-dependent ecosystems is not fully considered in the current framework. Water quality problems in the Basin, such as salinity, suspended sediment, and sediment-attached phosphorus, have impacted water use and riverine ecosystems. Climate change is also a significant challenge, with projections indicating a drier future and a decline in mean annual runoff, which will increase the gap between water demand and supply. To address these challenges, there is a need for improved management of water resources, integrated management of aquifer and surface water resources, and consideration of cumulative environmental changes.
How droughts affects biodiversity in australia?5 answersDroughts in Australia have significant impacts on biodiversity. The effects of drought on plant communities and vegetation growth are determined by aerodynamic fluxes in the atmosphere, available soil water and nutrients, and exposure to solar radiation. Higher-diversity plant communities have been found to buffer against the negative effects of drought, either by including more drought-resistant species or by improving the performance of drought-sensitive species. However, the impact of drought on forest biodiversity and ecosystem functioning is generally negative, with decreased productivity and increased mortality observed. Droughts in Australia are recurrent and natural, but our ability to monitor, forecast, and manage drought is limited. Understanding and managing drought require research on defining and monitoring drought characteristics, documenting historical variation, and improving prediction and projection of drought. The nature and causes of droughts in Southeast Australia vary, highlighting the need for further research into understanding and representing hydroclimatic drivers of drought.