Periodic Reporting for period 1 - RIDDLE (Dams and Dolphins: Linking cutting-edge science with endangered species conservation)
Período documentado: 2020-09-01 hasta 2022-08-31
The exceptional loss of biodiversity over the last few centuries has been described as a sixth mass extinction. Vertebrate species are disappearing at 100 times background extinction rates. The planet is changing faster than scientists can document that change, let alone be effective on the scale and speed required to try to prevent it.
Freshwater habitats occupy only 1% of the Earth’s surface yet are biodiversity hotspots that support 10% of all known species, and a third of vertebrate species, however, they are intensely used, modified and degraded by humans. As a result, there are severe declines in the range and abundance of many freshwater species, so that they are now even more imperilled than their marine or terrestrial counterparts. Only 37 per cent of rivers longer than 1,000 kilometres remain free flowing over their entire length; dams and their downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity and biodiversity. The number of dams is increasing globally, and climate change will likely accelerate the associated environmental impacts. Freshwater megafauna species (e.g. predatory fish, otters, crocodiles, turtles, gharial, manatees, caimans, dolphins etc.) are amongst the most vulnerable species, and as the top predators in many systems their extirpation often leads to large changes in aquatic community structure through trophic cascades which also impact human communities that rely on those resources. Among these aquatic top predators are freshwater dolphins and porpoises, little known animals that occur in 15 countries, and 9 river systems in two continents (Asia and South America). There are river dolphins in some of the largest freshwater systems: the Yangtze, Amazon, Orinoco, Mekong, Irrawaddy, Brahmaputra, Ganges and Indus, and they are one of the most threatened animal groups; listed as endangered or critically endangered on the IUCN Red List in all places they occur. One of the major causes of this endangerment is the construction and presence of dams. These are in the form of run-of-the-river hydropower schemes, high storage dams, weirs or gated diversion dams (hereafter all termed ‘dams’) each of which fragment populations and deplete and degrade habitat in differing ways. The speed with which river dolphin species can go extinct was exemplified by plummeting population and subsequent extinction in 2006 of the Yangtze River dolphin; the first vertebrate extinction in the last 50 years.
In July 2019 the International Whaling Commission convened a River Dolphin Task Team which made a number of high priority recommendations regarding river dolphins and dams that were then endorsed by the Scientific Committee meeting and circulated to Contracting Parties and Member States. Key recommendations were: 1. that, as a priority, studies be conducted to fully understand movements of dolphins across barrages in all countries and quantify the extent of population connectivity and impacts on dolphin populations in fragmented riverine habitats; and 2. that possible tools be evaluated and trialled to reduce the number of dolphins becoming trapped in canals.
The overall goal of this Fellowship was to bring together the cross-disciplinary expertise and cutting-edge technology to tackle these complex issues to help solve the challenge of sustaining river dolphin populations in dammed and regulated rivers.
Freshwater habitats occupy only 1% of the Earth’s surface yet are biodiversity hotspots that support 10% of all known species, and a third of vertebrate species, however, they are intensely used, modified and degraded by humans. As a result, there are severe declines in the range and abundance of many freshwater species, so that they are now even more imperilled than their marine or terrestrial counterparts. Only 37 per cent of rivers longer than 1,000 kilometres remain free flowing over their entire length; dams and their downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity and biodiversity. The number of dams is increasing globally, and climate change will likely accelerate the associated environmental impacts. Freshwater megafauna species (e.g. predatory fish, otters, crocodiles, turtles, gharial, manatees, caimans, dolphins etc.) are amongst the most vulnerable species, and as the top predators in many systems their extirpation often leads to large changes in aquatic community structure through trophic cascades which also impact human communities that rely on those resources. Among these aquatic top predators are freshwater dolphins and porpoises, little known animals that occur in 15 countries, and 9 river systems in two continents (Asia and South America). There are river dolphins in some of the largest freshwater systems: the Yangtze, Amazon, Orinoco, Mekong, Irrawaddy, Brahmaputra, Ganges and Indus, and they are one of the most threatened animal groups; listed as endangered or critically endangered on the IUCN Red List in all places they occur. One of the major causes of this endangerment is the construction and presence of dams. These are in the form of run-of-the-river hydropower schemes, high storage dams, weirs or gated diversion dams (hereafter all termed ‘dams’) each of which fragment populations and deplete and degrade habitat in differing ways. The speed with which river dolphin species can go extinct was exemplified by plummeting population and subsequent extinction in 2006 of the Yangtze River dolphin; the first vertebrate extinction in the last 50 years.
In July 2019 the International Whaling Commission convened a River Dolphin Task Team which made a number of high priority recommendations regarding river dolphins and dams that were then endorsed by the Scientific Committee meeting and circulated to Contracting Parties and Member States. Key recommendations were: 1. that, as a priority, studies be conducted to fully understand movements of dolphins across barrages in all countries and quantify the extent of population connectivity and impacts on dolphin populations in fragmented riverine habitats; and 2. that possible tools be evaluated and trialled to reduce the number of dolphins becoming trapped in canals.
The overall goal of this Fellowship was to bring together the cross-disciplinary expertise and cutting-edge technology to tackle these complex issues to help solve the challenge of sustaining river dolphin populations in dammed and regulated rivers.
The majority of the activities conducted during the fellowship were focussed on two river systems; the Indus of Pakistan and the Ganges system in India and Nepal. The project brought together experts from across the South Asian region to collaborate on river dolphin research and conservation, to use technology to assess and address threats from fishing and fragmentation and improved knowledge substantially on population dynamics, taxonomy, and trends in abundance of these threatened species. During the course of the fellowship detailed studies were conducted on distribution, abundance, preferred habitat and metapopulation dynamics of each small isolated population of Indus River dolphin in Pakistan to give a detailed understanding of the impact of dams and habitat fragmentation on the species. Information on the habitat use and movement patterns of dolphins in unimpacted parts of the river were conducted demonstrating that animals are concentrated into deep areas during the dry season and that 90% of the river is not suitable habitat. During the fellowship work that brought together decades of work on the ecology and biology of Indus and Ganges river dolphins was integrated to show that the two endangered populations are in fact distinct species that warrant seperate management. Working as part of the River Dolphins Initiative, Chair of the Global Coalition for River dolphin conservation and Deputy Chair of the IUCN Cetacean Specialist Group extensive liaison with the authorities in India, Bangladesh and Pakistan was conducted regarding improved water policy and new water infrastructure projects and best practices for population assessment, habitat assessment and river dolphin conservation were produced and published online.
The work conducted during this fellowship was focussed on improving knowledge and the scientific technology for understanding and addressing threats to aquatic megafauna species in large tropical rivers. The information on best practices in survey methods for assessing river dolphins and habitats that was provided to the Indian and Bangladeshi governments, South Asian scientists, and water managers advanced the ability to both monitor impacts of new developments and address potential negative effects. Data on the trends in abundance and conservation status of Indus River dolphins in Pakistan and in India is vital for the respective governments to manage these species. The work conducted during the fellowship was a collaborative effort that brought together the academic, industry and NGO sectors to address a complex problem. Collaborating with WWF and the World Bank provided a much larger platform for dissemination of information and to provide scientific advice to those that are using it.
Throughout the period of the fellowship the researcher spent a great deal of time teaching and mentoring younger scientists from developing world countries. This included mentoring, teaching or supervising female researchers from Pakistan, Iran, India, Tanzania, Papua New Guinea and Indonesia. A number of training courses were conducted in Pakistan and India regarding the most appropriate methods for conducting population assessments of river dolphins in South Asia which is essential for evaluating the impact of future water development projects. The work will be continued through a new PhD study by a Pakistani student who will continue under my guidance, to extend the work by providing detailed insights into the impact of threats from shipping, plastics and fishing on river dolphins in South Asia.
Throughout the period of the fellowship the researcher spent a great deal of time teaching and mentoring younger scientists from developing world countries. This included mentoring, teaching or supervising female researchers from Pakistan, Iran, India, Tanzania, Papua New Guinea and Indonesia. A number of training courses were conducted in Pakistan and India regarding the most appropriate methods for conducting population assessments of river dolphins in South Asia which is essential for evaluating the impact of future water development projects. The work will be continued through a new PhD study by a Pakistani student who will continue under my guidance, to extend the work by providing detailed insights into the impact of threats from shipping, plastics and fishing on river dolphins in South Asia.