This summer was England’s hottest on record, tied with 2018. The average temperature in June, July and August was 17.1°C. Four out of the five warmest summers have occurred since 2003, with records stretching back to 1884. Hot and dry conditions are causing river levels to drop, crop damage and wildfires across England.
East Yorkshire has launched a climate change consultation, inviting residents and those who work in the area to contribute to the local authority’s response. Attendees will get a first look at the draft Climate Change Strategy developed by East Riding of Yorkshire Council, which will highlight opportunities for future action. A survey has also been created to gather people’s views on climate change from across the authority area.
Research
Ecologists are using the latest dental scanning technology to study young coral, monitoring coral size and growth. This method is said to have reduced surveying time by 99%. Dr Kate Quigley, a senior research scientist, has developed a new non-destructive method for rapidly and safely scanning coral, using an ITero Element 5D Flex dental scanner. Because coral and teeth are both calcium-based, the scanner works effectively, allowing scientists to measure thousands of tiny coral quickly, accurately and without any negative impacts on the health of the coral.
Conservation
A flock of European bee-eaters have migrated south for the winter after successfully hatching chicks in the UK. The arrival of the breeding colony in Trimingham, Norfolk, in June was described by the RSPB as a “red alert for global warming,” as they are more commonly found in the southern Mediterranean and northern Africa. Nesting bee-eaters are occurring in the UK as hotter, drier summers become more common. While they eat a variety of flying insects, including many bee species, this small colony is not expected to have had any impact on local bee populations.
European Bee-eater by Francesco Veronesi via Flickr
Water voles have been reintroduced into the New Forest, two decades after they became locally extinct. In 1998, 7000 American Mink were released from a fur farm by animal rights activists, inadvertently resulting in the loss of the local population of endangered water voles. The Environment Agency released 50 captive-bred water voles into an area near Ringwood, joining a few wild voles relocated from Salisbury. Another 50 will be introduced to the same area next spring, with the hope that the population will reach 1,000 by 2027.
A rare sea slug, Babakina anadoni, has been spotted in Cornwall, marking only the second time this species has been seen in UK waters. The first sighting was made by a Seasearch volunteer just a few weeks ago off the Isles of Scilly. Their larval stage is thought to have drifted in on ocean currents, with the adults surviving due to favourable conditions. Only a few individuals have been spotted around the world, mostly in warm waters off the west coast of Spain, as well as Portugal, France, Brazil and the Caribbean.
Babakina anadoni by Carlos Fernandez-Cid via Flickr
Policy
A ban on offshore oil and gas exploration by Shell has been upheld by a South African court. Due to the loud shock waves that would occur every 10 seconds for the five-month period, it is thought that the seismic waves used to explore the Indian Ocean coast for oil and gas would have a negative impact on whales and other marine life in the area. These surveys have been found to disrupt marine communication, navigation and eating habits, which are essential to the survival of marine life. They also damage fish air bladders, marine eggs and larvae and can cause species to temporarily migrate away from the affected area. This may have knock-on effects on local fisheries.
River water testing fell to a 10-year low last year, with only 41,519 samples tested compared to 100,000 in 2012. Experts warn that this is causing a ‘vacuum of knowledge’ about river pollution and its effects. The decrease in monitoring has coincided with repeated cuts to the Environment Agency budget. Pollution risks increase with low-flowing rivers, such as the conditions brought on by recent droughts, because the concentration of pollutants increases.
With publication of the August issue of British Wildlife, the magazine’s 33rd volume is complete. While we wait for the start of volume 34, in October, we have taken the opportunity to look back at some of the themes and topics covered during the past year, ranging from in-depth natural histories of species and places, to critiques and commentaries on key topics in environmental policy. The selection below offers just a small sample of recent subjects – for a full list of articles from volume 33 and further back in the magazine’s history, visit the British Wildlife website.
Species-focused articles have spanned the taxonomic spectrum, covering everything from fungi through to the (long-extinct) elephant species that roamed Britain through prehistory. Further mammalian subjects have included the Walrus and other Arctic vagrants and a long-term study of Greater Horseshoe Bats in south-west Wales, while, turning to the more ‘obscure’, we have seen pieces on the Narrow-headed Ant and Brilliant Emerald dragonfly, two rare insects with unusual split distributions in Britain, the remarkable biology of limpets and their influence on rocky-shore ecosystems, and the identification of British Stropharia fungi. Meanwhile, contributions on botany have explored the culture and ecology of Common Elder, and the place of Wild Leeks in Welsh history.
33.7 June 2022
Places featured include the unique primeval floodplain forest of the Gearagh in south-west Ireland; the surprisingly diverse grasslands formed on toxic mine spoil and metal-rich rocks in northern Wales; the vibrant St Nicholas Fields, an urban Local Nature Reserve in the heart of York; the varied submerged and coastal habitats of Plymouth Sound, Britain’s first National Marine Park; and Beinn Eighe NNR in the western Highlands, which in 2021/22 is celebrating its 70th year as a National Nature Reserve.
33.5 April 2022
Other articles have reviewed some of the most serious challenges for conservation, such as the disruption to invertebrate life-cycles caused by climate change, and the ecosystem-level impacts of overabundant carrion in the countryside. Meanwhile, on a practical level we have seen case studies on work to restore dynamism to Welsh sand dunes, the conservation of beach-nesting Ringed Plovers, the effects of grazing by cattle on the vegetation of lowland heathland, and techniques for finding and reviving ‘ghost ponds’ – old infilled farm ponds – for the benefit of aquatic species and other farmland wildlife.
Looking ahead, readers can expect a similarly eclectic mix from volume 34, including contributions on the folklore of the alluring but highly poisonous plant Henbane, the creation, management and wildlife of the Gwent Levels, the history of the Black Rat in Britain, efforts to conserve Black-tailed Godwits in the fens of East Anglia, further articles in the Wilding for Conservation series, and much more.
33.8 August 2022
British Wildlife is a subscription-only magazine published eight times per year: visit www.britishwildlife.com or email info@britishwildlife.com for more information. Individual subscriptions start from just £40 – you can subscribe online or by phone (01803 467166). Individual back issues of British Wildlife are available to purchase through the NHBS website.
2022 is a big year for politics and nature. Following on from COP26, which was largely concerned with climate change, the end of this year will see the convening of COP15 in which the world’s nations will come together to discuss the preservation of global biodiversity. Now more than ever, it is important for conservation and biodiversity to be at the forefront of politics.
With this in mind, we are taking a look at the Species Champions Project, which involves MPs and wildlife organisations working together to improve the future for our most threatened species.
What is the Species Champions Project?
The Species Champions Project aims to bring political support to the protection of threatened species by pairing Members of Parliament (MPs) with a particular species. MPs are often linked to species that are of local importance in the region that they represent, or they have a particular interest in.
The project began in 2016 and, to date, more than 50 MPs in England have gotten involved. They represent a diverse range of species including European salmon, curlew, glow-worms, marsh fritillary and natterjack toads. Similar initiatives are also in place involving MPs from Scotland, Wales and Northern Ireland.
Who runs this project?
The project is run by Rethink Nature, a partnership of seven wildlife organisations which include: Amphibian and Reptile Conservation, Bat Conservation Trust, Buglife, Bumblebee Conservation Trust, Butterfly Conservation, Plantlife and the RSPB. The Angling Trust, the People’s Trust for Endangered Species and the British Hedgehog Preservation Society provide further support.
Debbie Abrahams, Labour MP for Oldham East and Saddleworth, is the Species Champion for the marsh fritillary. Image by Chris Parker via Flickr.
What do Species Champions do?
Species Champions are responsible for raising awareness of their assigned species, both within their constituency and in Parliament. They work towards changing policy and legislation in a way that benefits the species and the habitat that it requires to thrive.
During 2022 there are several key areas that Species Champions will be working on: October 31st is the deadline for targets to be set for the Environment Act, and it is vital that these are ambitious enough to serve both wildlife and their supporting habitats. The COP Convention of Biological Diversity is a key event at which the UK should be fighting hard for a strategy to reverse biodiversity loss over the next few years. Finally, the Government’s promise to protect 30% of land and sea by 2030 needs to be supported and upheld.
Why is this project important?
The majority of conservation efforts happen on the ground and in the field. While this work is crucial, there also needs to be work done at the political and legislative level, so that policies and environmental laws show a commitment to protecting the species that need it most. Britain is home to a huge number of species that are currently under threat due to a combination of land-use changes, intensive agricultural practices, habitat loss/fragmentation and pollution. Bringing these issues into Parliament and to constituents is the main aim of the Species Champions Project.
Where can I find out more?
For a full list of the MPs involved in the Species Champions Project and the species that they are twinned with, visit the Species Champions website. Is your MP on the list? If not, then why not get in touch with them and encourage them to get involved!
There is widespread drought and water shortages across parts of Europe, including areas of England and Germany (where water levels in the Rhine River have dropped significantly), as well as France, Italy, Spain, Netherlands and Belgium. This is Europe’s most severe drought in decades, with high temperatures and reduced rainfall testing infrastructure and water supplies. England experienced the driest July since 1935, with only 35% of average rainfall for the month falling. Other rivers such as the Danube and the Po have been impacted, threatening wildlife.
Research
Most sharks killed for fins are at risk of extinction. A new study has found that more than two-thirds of sharks hunted and used in the global fin trade are at risk of extinction. By studying 9,820 shark fin trimmings from markets in Hong Kong between 2014 to 2018 using DNA analysis, the researchers found 86 different species. Of these, 61 are threatened with extinction. The majority of fins came from blue sharks which are classified as “near threatened” by the IUCN, with the other top species including silky sharks, hammerheads, makos and threshers.
Self-pollinating plants are showing rapid loss of genetic variation. Flowering species that can self-pollinate lost genetic diversity within only nine generations without bumblebees. A new study has found that monkeyflower plants lost between 13–24% of their genetic variation compared to a group that was propagated by bumblebees. Reducing genetic diversity can limit a species’ ability to adapt to environmental changes, like those brought on by climate change. This study highlights the importance of pollinator species in combating the impacts of the climate crisis.
Conservation
Derbyshire conservationists aim to save Swifts by pushing housebuilders to install nesting bricks. These hollow bricks provide a nesting area for one of the UK’s most endangered birds, whose population has dropped by 65% in the last 25 years. The Derbyshire Swift Conservation Project, run by Derbyshire Wildlife Trust, aims to raise awareness of Swifts. This aim is now increasingly being included in planning applications for new housing.
Cornish Choughs have had a bumper year, 20 years since the first Cornish-born Choughs were seen once again. Over 70 youngsters are being raised by 25 pairs, bringing the total population to around 200 birds. Just a single pair successfully fledged young in 2002 and now Choughs can be seen all over Cornwall.
Critically endangered Albatrosses are being plagued by mice on Gough Island. This small British overseas territory in the South Atlantic is home to the Triston Albatross, along with 21 other seabird species. Mice were introduced to the island accidentally over two hundred years ago. With no existing predators, the mouse population exploded, leading to a decline in seeds and insects. In response to this drop in food supply, some mice began to prey on seabird chicks. Last year, there was an attempt to eradicate this invasive species by dropping poisoned mouse bait all over the island but this attempt failed. The mice are now once again spreading across the island.
In brighter news, the saiga antelope population has increased 10-fold after a mass die-off in 2015. A fatal bacterial disease killed around half of the population, leaving only 130,000 animals. Now, an estimated 1.3 million saiga are living in the steppe grasslands of Kazakhstan. After being hunted to the brink of extinction, numbers were down to less than 40,000 in 2005. This new increase is the result of land protections and hunting bans, which have allowed the species to begin recovering.
Policy
The US Senate has passed a sweeping climate, tax and healthcare package, which will increase corporate tax, lower the cost of some medicines and, importantly for the fight against climate change, reduce carbon emissions. The $700bn (£577bn) economic package includes $369bn (£305bn) dedicated to climate action, the largest climate investment in US history. This will be split into multiple projects, including speeding up the production of clean technology, providing tax credits for those who buy an electric car and funding for communities that have suffered the most from fossil fuel pollution.
Endangered species breeding programmes are under threat due to new EU regulations. The EU Animal Health Regulation came into force in April 2021, after being agreed in 2016, creating new controls on the import of animals and plants into the EU. These new sanitary and phytosanitary checks must be carried out at border control posts, but few exist at airports in the EU and none at French ports. Before December 2020, there were an average of 1,400 transfers of species between the UK and other EU countries in order for breeding programmes to keep the gene pool as broad as possible. But since Brexit, there were just 56 in 2021, and so far this year, there have only been 84. The lack of checking posts has effectively banned the import of any large animal, potentially preventing the breeding of certain endangered species, such as the black rhino.
The UK is home to a single native species of crayfish – the white-clawed crayfish Austropotamobius pallipes. This attractive freshwater crustacean has a bronze-coloured body and white-undersides to its claws, for which it is named. They require clean freshwater habitats such as streams, rivers and lakes where they can rest under stones and rocks during the day and then spend the night foraging for food. Their diet is omnivorous and they feed on a range of foods including plants, carrion and invertebrates. They will also eat other white-clawed crayfish when the opportunity arises!
Image by David Gerke via Wikimedia Commons CC BY-SA 3.0
Threats to native UK crayfish
The white-clawed crayfish was once widespread and common throughout England and Wales, but since the 1970s populations have declined by 50–80%. Without intervention it is expected that they will become extinct over the next 20 years. Their decline is in large part due to the introduction of the North American signal crayfish which outcompetes the native crayfish for food and habitat. The signal crayfish also carries ‘crayfish plague’, a fungal disease that the white-clawed crayfish has no natural resistance to. Declining water quality and loss of suitable freshwater habitats have also contributed to their decline.
How are crayfish protected in the UK?
White-clawed crayfish are fully protected under the Wildlife and Countryside Act 1981 and The Conservation of Habitats and Species Regulations (2017). As a result, it is an offence to kill, injure or disturb them and their habitat cannot be destroyed or damaged. Any development which will, or is likely to, impact white-clawed crayfish and their habitat will only be allowed if it provides a net benefit to the crayfish through a combination of mitigation, compensation and enhancement strategies. This may involve habitat restoration projects or the modification of existing freshwater areas to make them more suitable for crayfish to survive and thrive.
When and how are crayfish surveyed?
Crayfish surveys are required if a development is being planned in an area that currently supports, or has the potential to support, white-clawed crayfish. They can be surveyed using a variety of methods including relatively new eDNA technology, which analyses water samples to detect the presence of DNA specific to the white-clawed crayfish. eDNA studies, however, cannot provide information on population size and so follow-up surveys are usually required should eDNA be detected. Most commonly crayfish are surveyed by manually searching likely refuges. If this isn’t possible due to access issues or water depth then crayfish traps can be deployed. These traps are of the live-catch variety – trapped individuals are returned to the water unharmed once they have been recorded.
What else is being done to conserve the white-clawed crayfish?
As well as being afforded a high level of protection in UK legislation, there are a number of conservation projects which aim to conserve or bolster existing populations of white-clawed crayfish. As part of the South West Crayfish Project, Bristol Zoo are breeding white-clawed crayfish in captivity which can be used to boost existing populations or establish new ones. They are also valuable in educating zoo visitors about their plight.
Control of introduced crayfish is also being carried out in certain areas through trapping or the use of biocides. Similarly, the control of plague and other crayfish diseases is of paramount importance. All waterway users should be aware of how easily plague spores are carried between sites and make all reasonable efforts to stop it spreading via their clothes and equipment. Download the Crayfish in Crisis information sheet for more information.
Recommended reading and equipment
Crayfish Conservation Manual
Full of guidance and practical advice, this large, full-colour manual is the first conservation handbook for England’s crayfish. This manual provides best practice advice and guidance in one easy-to-follow publication, with references, case studies and examples.
Management of Freshwater Biodiversity: Crayfish as Bioindicators
Integrating research into freshwater biodiversity and the role of keystone species, this fascinating book presents freshwater crayfish as representatives of human-exacerbated threats to biodiversity and conservation.
Trappy Funnel Crayfish Trap
This robust all-plastic crayfish trap is very easy to handle and quick to set and re-bait.
Aluminium Crayfish Refuge Trap
This simple refuge trap is safe for use where water voles and otters are present.
Snowbee Granite PVC Chest Waders
Snowbee Granite waders are manufactured from a heavy-duty, reinforced laminate PVC which is extremely tough and hard-wearing while also being soft and flexible for ease of movement.
The Mediterranean ecosystem is suffering the equivalent of a marine wildfire as temperatures in the area are more than 6°C warmer than normal. It is feared that the area is being permanently altered by global heating, with cooler deep water no longer rising to the surface. One study found that these marine heatwaves have already destroyed almost 90% of coral populations around parts of the Mediterranean. This decline has knock-on impacts on biodiversity within the marine ecosystems of the area.
A new project is looking at the genetic differences between bee species. ‘Beenome100’ will look to answer questions on which genetic differences make some species more vulnerable to climate change or more susceptible to different pesticides. By creating a digital repository of the complete set of genes present in 100 US bee species, scientists can link specific genes to bee functions.
Between 1986 and 2020, invasive herpetofauna cost the world $17 billion, $16.3 billion of which were associated mainly with just two species, the brown tree snake (Boiga irregularis) and the American bullfrog (Lithobates catesbeianus). This cost mainly comes from ruined farm crops and triggered power outages. The study’s researchers are hoping that their findings will encourage investment in preventing the spread of invasive species in the future.
Scientists have recorded more than 30 potentially new species from the abyssal plains of the central Pacific. Researchers from the Natural History Museum used a remote-operated vehicle to reach depths of between 3,095 and 4,125 metres and collect over 55 specimens. These specimens include segmented worms and coral, as well as species from the same families as centipedes and jellyfish. The study highlights the potential implications of deep-sea mining for biodiversity.
Conservation
UK wild salmon stocks are reaching a crisis point, with the lowest number on record in England. A government report urges action to remove barriers in waterways and improve water quality. 42 rivers in England are considered ‘salmon rivers’ as they are traditional breeding grounds for the fish. Of these, 37 have been classified as at risk or probably at risk. Warming sea temperatures due to climate change are being blamed, along with poor water quality in rivers and estuaries, with every waterway in England failing pollution tests in 2020. The main sources of pollution are thought to be sewage outflows and agricultural runoff.
Water voles have been reintroduced to the River Beane in Hertfordshire after being locally extinct for more than 20 years. Threatened by habitat loss and predation by the invasive American mink, the species has seen a 90% drop in population over the last five decades. Herts and Middlesex Wildlife Trust, in partnership with the Woodhall Estate and with the support of the River Beane Restoration Association, reintroduced 138 water voles to the river near Watton-at-Stone. Herts and Middlesex Wildlife Trust aim to reintroduce water voles to all Hertfordshire rivers by 2030, through these reintroduction programmes and by improving habitats.
A new Antarctic study has shown that the levels of ‘forever chemicals’ that are reaching this remote continent have been increasing. These chemicals include perfluorocarboxylic acid (PFCAs) and are termed forever chemicals as they do not break down naturally in the environment. They’re used in a variety of ways, such as in non-stick coating for pans and as water-repellents for clothing. The ice cores taken provide a record between 1957 and 2017 and show evidence that levels of these chemicals in Antarctic snow have increased over the last few decades, particularly between 2000 and 2017. There is ongoing research, however, into the clean-up of these forever chemicals, including a new study into bioremediation using a plant-derived material to absorb PFAs, disposing of them by allowing microbial fungi to eat them.
Deforestation
A new study has found that over 60% of global forest area has been lost. Using a global land use dataset, the team of researchers found that global forest area declined by 81.7 million hectares (ha) between 1960 and 2019. Gross forest loss was 437.3 million ha, outweighing gross forest gain during this time, which was 355.6 million ha. The loss of forests, both in the net area and through replacement by new growth/plantations, has a significant impact on the integrity of forest ecosystems, reducing their ability to sustain biodiversity.
In the lead up to the 26th UN Climate Change Conference of the Parties (COP26) in November of last year, and in the months that have followed, we have been writing a series of articles looking at some of the toughest global climate crisis challenges that we are currently facing. This blog looks at the causes of ocean warming and its impacts on marine ecosystems.
Dead coral at Lisianski overgrown with algae after a coral bleaching event in 2015. Image by John Burns via Flickr.
What causes ocean warming?
The ocean acts as a heat sink, absorbing large amounts of heat from our atmosphere and storing it over long periods; the ocean has a central role in stabilising our climate system. This heat is moved and mixed by tides, currents and wave action, allowing the ocean to soak up large amounts of heat without significant increases in temperature. This is changing, however, due to increasing concentrations of atmospheric greenhouse gases. IPCC data published in 2013 suggested that the ocean has absorbed over 90% of the excess heat generated by greenhouse gas emissions since the 1970s. This is resulting in increased ocean temperatures, with the greatest warming occurring in the southern hemisphere and in the upper 75m of the oceans surface. Average global ocean surface temperatures increased by 0.11°C per decade from 1971 to 2010. This heat sink process has helped limit the rise of global average temperatures but it has serious environmental consequences.
What are the impacts of ocean warming?
Ocean warming has a wide range of impacts on ocean chemistry, habitats, ecosystems and biodiversity, the severity and type of which can vary between habitats depending on their resilience and present biodiversity levels. Combined with other stressors such as pollution, acidification and increased nutrient input, ocean warming can increase the vulnerability of habitats and marine life to other threats such as parasites and disease outbreaks.
Water temperature is a significant environmental stressor, particularly in shallow or nearshore habitats, as they often act as nursery areas for many species. If water temperatures within nursery habitats rise above tolerable levels, they will no longer be suitable, impacting the survivorship, growth and recruitment of the species that use them.
Fishing net tangled on a reef. Image by Tim Sheerman-Chase via Flickr
Deoxygenation
Oxygen solubility varies depending on the temperature of the water; warmer ocean water holds less oxygen compared to colder water. Warmer water is also less dense, and rising ocean temperatures leads to increasing ocean stratification, where water is separated into layers. This can act like a barrier and prevents the mixing of water, slowing down ocean circulation and reducing the amount of oxygen reaching deeper waters. It is thought that dissolved oxygen levels have fallen by 2% since the 1950s due to the combined threats of ocean warming and excessive algae growth caused by anthropogenic nutrient input. Areas of low oxygen concentrations have expanded worldwide, with hundreds of new sites reported to be affected and anoxic ocean waters quadrupling in volume since the 1960s.
Ocean deoxygenation has serious consequences for marine ecosystems and biodiversity, as oxygen is necessary to sustain life for almost all organisms in the ocean. Deoxygenation could lead to a decline in species numbers, diversity and individual growth, resulting in major ramifications throughout the food chain. In ecosystems already vulnerable due to other pressures such as overfishing, deoxygenation could lead to extinctions and even deadzones. Hundreds of millions of people rely on the oceans as a source of food and livelihood; they could be severely affected by a reduction or collapse in fish stocks.
Warmer waters also increase the oxygen requirement of fish, exacerbating the effects of deoxygenation. There will likely be a shift in the structure of marine ecosystems as more hypoxia-tolerant species, such as jellyfish, will be favoured over less tolerant species, such as large fish and marine mammals.
Coral bleaching
Corals are marine invertebrates that often have a hard calcium carbonate skeleton. They live in a mutualistic symbiotic relationship with photosynthetic unicellular dinoflagellates called zooxanthellae (endosymbionts), which live in their tissues. They rely on these endosymbionts for up to 95% of their energy requirements. Under certain physiological stresses, such as increasing water temperatures, these endosymbionts can be expelled and the corals turn white without the pigment from the zooxanthellae – this phenomenon is known as ‘coral bleaching’. If the stress continues over an extended period and the coral is not recolonised, the coral will eventually die. Increasing ocean temperatures over the last few decades have resulted in large-scale loss of coral across the world. This has led to degraded coral reef habitats, impacting the ecosystem and species that rely on them. Coral reefs provide food, shelter and spawning grounds for thousands of marine species, therefore the degradation of coral reefs has wide-reaching consequences.
Bent sea rod bleaching. Image by Kelsey Roberts, U.S. Geological Survey via Flickr
Habitat loss and range shifting
All species have a thermal tolerance range. Some more generalist species are able to tolerate a broader range, but specialist species occupy a much narrower thermal niche and are therefore more vulnerable to temperature change. Temperature changes can trigger a knock-on effect on ecosystem structures as species migrate into more suitable habitats. The general trends in these shifts are a movement to higher latitudes and deeper locations.
Many factors affect a species’ capacity to adapt to rising temperatures, including their dispersal ability, thermal tolerances, habitat or resource needs and the community composition of the new potential habitat. If the new area has high levels of pressure from competition, predation or lack of resources, or the species’ dispersal ability is limited (e.g. the species is sessile), successful establishment is unlikely.
Commercial fishing boat. Image by Gary Leavens via Flickr
Changes in community structure can negatively impact biodiversity, as the loss of whole populations from initial habitats can trigger a cascade of consequences on predator and prey populations, potentially altering entire ecosystems. These range shifts can also impact the communities already present, as new species could lead to increased competition for resources or the arrival of a novel predator that prey species are not adapted to avoid. There will also likely be socio-economic impacts on local fisheries if species move away from traditional fishing grounds.
Range shifting has been recorded in zooplankton, where warm-water species are extending their ranges poleward at a rate of up to to more than 230km per decade. There has also been a corresponding decline in the abundance of cold-water species in these areas. Zooplankton play a key role in many food chains as they are an intermediary species, transporting energy from the primary producers (phytoplankton) they consume to their predators, such as fish and decapods. Therefore, these changes in zooplankton community composition impact whole marine food webs, especially as warm-water species are generally smaller and less energy-rich.
Radiolarian zooplankton stack images, composed of dozens of single photographs taken using a microscope at different focus levels. Images 1, 2, and 3 by Picturepest via Flickr.
Temperature-dependent sex determination
Some marine species exhibit environmental sex determination, where certain environmental factors can influence the sex of offspring during embryonic or early juvenile development. With increasing ocean temperatures, the proportion of males to females being born could be altered in certain species, leading to biased sex ratios. This can affect reproduction, genetic diversity and potentially population numbers.
Many fisheries are female-dependant, as female fish tend to grow larger, therefore are more likely to grow to harvestable sizes and can produce a larger yield. Southern flounder (Paralichthys lethostigma) exhibits sex reversal to males during early juvenile development at both 18°C and 28°C, with the optimal temperature for female development being 23°C. Southern habitats consistently have higher temperatures of over 27°C, therefore producing more male-biased sex ratios, potentially impacting the viability of fisheries operating out of these locations.
Other impacts
Warming ocean temperatures are also thought to be impacting breeding patterns, with many species reproducing earlier. This could lead to an uncoupling of certain predator and prey interactions if migrating predators arrive too late to feed during spawning events. Some species have been found to breed for a shorter duration, such as black sea bass (Centropristis striata) whose spawning season is starting later and ending earlier in the northern parts of their range. This suggests that there may be lower reproduction and recruitment in newly occupied ranges, demonstrating the potential future impact of warming ocean waters on species experiencing poleward-driven range shifts. Migration patterns have also been noted to be affected, with similar potential results.
Ocean warming also reduces the amount of sea ice. The implications of this, such as sea-level rise, coastal flooding and erosion, will be covered in more depth in a future blog post.
Coral spawning. Images 1 and 2 by Pei Yan via Flickr
What can be done?
As the main driver for increasing ocean temperatures is the increase in atmospheric greenhouse gases, particularly carbon dioxide, the solution is to reduce our greenhouse gas emissions. Beyond this, we need to protect and restore our marine and coastal ecosystems and manage the other stressors that are exacerbating the impacts of ocean warming. By creating protected areas and restoring degraded habitats, we can create refuges for species and improve biodiversity, which has been shown to increase ecosystem resilience against the impacts of climate change.
By working with fisheries, governments could introduce further policies that work towards sustainability, such as by improving quota limits and reducing by-catch. Many governments and fisheries are already working towards this, but scientific research and accurate data are needed to ensure that population estimates are accurate to prevent overfishing. Steps like these will help to reduce the pressures we place on the marine realm, allowing ecosystems to be more resilient to the effects of ocean warming.
Scientific research into monitoring ocean warming is also important. Up-to-date and accurate measurements, with local and global monitoring of the rates, trends and effects can help policymakers make rapid and correct decisions to mitigate the worst impacts. Many of the policies signed at COP26 may make a positive difference, as reducing deforestation and methane emissions and adopting policies to reach net zero by 2050 will help to limit ocean warming. However, more can and should be done.
Summary
Oceans absorb atmospheric heat, the amount of which has increased due to high greenhouse gas emissions. The greatest warming occurs in the southern hemisphere and the upper 75m.
Ocean warming has a variety of impacts including deoxygenation, habitat loss, range shifting, coral bleaching and changes to breeding patterns. These various impacts can all have negative effects on marine biodiversity and human livelihoods.
As the main driver for marine warming is increased greenhouse gas emissions, the main solution is cutting these emissions. Other solutions include protecting and restoring marine habitats, reducing pressures from other threats such as overfishing and increasing the accuracy and use of scientific research.
This book discusses the modifications in marine ecosystems related to global climate changes, including shifts in temperature, circulation, stratification, nutrient input, oxygen concentration and ocean acidification, all of which have significant biological effects.
Charles Clover chronicles how determined individuals are proving that the crisis in our oceans can be reversed, with benefits for both local communities and entire ecosystems. Essential and revelatory, Rewilding the Sea propels us to rethink our relationship with nature and reveals that saving our oceans is easier than we think.
This authoritative and accessible textbook advances a framework based on interactions among four major features of marine ecosystems – geomorphology, the abiotic environment, biodiversity, and biogeochemistry – and shows how life is a driver of environmental conditions and dynamics.
This special report is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks.
This offers a short, self-contained introduction to this subject, beginning by briefly describing the world’s climate system and ocean circulation and going on to explain the important ways that the oceans influence climate. Topics covered include the oceans’ effects on the seasons, heat transport between equator and pole, climate variability, and global warming.
Wally Broecker is one of the world’s leading authorities on abrupt global climate change. In The Great OceanConveyor, he introduces readers to the science of abrupt climate change while providing a vivid, firsthand account of the field’s history and development. This book opens a tantalizing window into how Earth science is practised.
We have recently received the sad news of the passing of James Lovelock, an environmentalist, chemist, futurist and the creator of the Gaia hypothesis.
Born in 1919, he attended the University of Manchester at age 21 and graduated with a PhD from the London School of Hygiene and Tropical Medicine in 1948, becoming an independent scientist in 1961. He had since been awarded honorary degrees from several institutions, including the University of Exeter, Stockholm University and the University of Colorado Boulder. His career was varied, from travelling aboard the research vessel RRS Shackleton to working on developing scientific instruments for NASA, and even performing cryopreservation experiments.
Lovelock was the first person to detect Chlorofluorocarbons (CFCs) in the atmosphere after developing an electron capture detector in the late 1960s. CFCs are nontoxic chemicals used in the manufacturing of products such as aerosol sprays, and are used as solvents and refrigerants. Their role in the depletion of the ozone layer led to their inclusion in the Montreal Protocol, which worked to phase out several substances to protect the ozone layer. During his time aboard the RRS Shackleton, Lovelock measured the concentration of CFC-11 from the northern hemisphere to the Antarctic. These experiments provided the first useful data on the widespread presence of CFCs in the atmosphere, though the damage these cause was not discovered until the 1970s, by Sherwood Rowland and Mario Molina.
James Lovelock was also known for his Gaia hypothesis. This hypothesis, first created in the 1960s, proposed that the complex interacting system of the Earth’s biotic and abiotic parts could be considered as a single organism. Drawing from research by Alfred C. Redfield and G. Evelyn Hutchinson, Lovelock formulated that living organisms interact with the non-living environment to form a synergistic and self-regulating complex system, by co-evolving with their environment. He suggested that the whole system, including the biosphere, atmosphere, hydrosphere and pedosphere, seeks an environment optimal for life. This evolution is facilitated through a cybernetic feedback system that is unconsciously operated by the biota, leading to a final ‘state’ of full homeostasis.
While the Gaia hypothesis is generally accepted by many in the environmentalist community, there has been some criticism, particularly from the scientific community. Lovelock later made revisions to the hypothesis to clarify that there was no conscious purpose within this self-regulating system and to bring the hypothesis into alignment with ideas from other fields, such as systems ecology. This had reduced criticism, but there still remains scepticism from the scientific community.
Lovelock wrote more than 200 scientific papers as well as a number of books on a variety of topics within chemistry, environmentalism, geophysiology, climate change and more. Lovelock’s work has been recognised a number of times, receiving awards such as the Tswett Medal in 1975, the Dr A. H. Heineken Prize for Environmental Sciences in 1990 and the Royal Geographical Society Discovery Lifetime Award in 2001. He was also appointed a member of the Commander of the Order of the Britsh Empire for services to the study of Science and the Atmosphere in 1990 and a member of the Order of the Companions of Honour for services to Global Environmental Science in 2003. In 2006, he was awarded the Wollaston Medal, an achievement also received by Charles Darwin.
The European Parliament has voted to ban ‘fly shooting’ fishing in a part of the Channel. This technique, also known as demersal seigning, involves towing weighted ropes along the seabed at either end of a net, which then encircles and captures entire shoals of fish. Fly shooter vessels catch up to 11 times more fish than inshore fishing vessels and have a devastating effect on the marine ecosystem, biodiversity and local fishers. This decision is seen as a victory for small-scale fishers but it will also help reduce the damage caused to the seabed and marine ecosystems in the Channel.
UK households recycle only 12% of single-use plastics, disposing of nearly 100 billion pieces of plastic packaging a year. A new survey by Greenpeace is one of the largest voluntary research projects on the scale of plastic waste and it asked households to count their plastic waste for one week in May. Almost 250,000 people from around 100,000 households took part and showed that the largest proportion of plastic waste was from food and drink packaging at 83%. The most common item was fruit and vegetable packaging. On average, each household threw away 66 pieces of plastic packaging in one week.
Pollution
The Environment Agency (EA) is calling for water company bosses to be jailed for serious pollution. Shocking levels of pollution occurred in the last year, with 62 serious incidents of pollution in 2021. The EA has stated that chief executives and board members of companies responsible for the most serious incidents should be jailed and that courts should impose much higher fines. Only three water companies received the highest rating of four stars for their pollution performance. The rating takes into account the number and severity of pollution incidents, as well as self-reporting and the use and disposal methods of sewage sludge. Two companies, Southern Water and South West Water, were given the lowest rating of one star.
Conservation
3D printed reefs are being used to restore marine biodiversity. WWF Denmark and Ørsted have been testing how structures made of 70% sand and 30% pozzolanic cement (a combination of volcanic ash and portland cement) could be used to create new habitats for fish and other wildlife in the Kattegat strait between Denmark and Sweden. Twelve of these structures have been deployed between the wind turbines at Anholt Offshore Wind Farm, and it is hoped that they will help reverse the decline of cod stock in the Kattegat.
Bison have been released into the wild in the UK. Wild bison are ecosystem engineers and can help to restore biodiversity in woodlands through their natural behaviours, such as felling trees by rubbing against them and grazing. This is hoped to provide a nature-based solution to tackling the climate and biodiversity crisis. The releases are part of a five-year project led by Kent Wildlife Trust and the Wildwood Trust. The next steps include introducing Exmoor ponies, Iron Age pigs and Longhorn cattle.
Contraceptives are being given to grey squirrels in an attempt to control their population and allow red squirrel populations to improve. Grey squirrels are a non-native species first introduced from North America in the 19th century. They cause significant damage to UK woodlands as they strip the bark from trees, and they tend to target younger trees that are typically between 10-50 years old, either killing them or maiming them and leaving them vulnerable to pests and diseases. Culling has not been found to be a sufficient control measure, therefore it is thought that using contraceptives, which have longer-lasting effects, may be more effective.
Young Maori divers are hunting invasive crown-of-thorns starfish to save coral reefs. The species, also known as taramea, feed on coral reefs and, when there are too many individuals, can destroy reef habitats. Korero O Te `Orau, a local environmental organisation, has been training young Maori people in scuba diving to remove taramea from the reef and bury them inland. The recent outbreak of this species around the island of Rarotonga in the Cook Islands could jeopardize the survival of the surrounding coral reef if not tackled properly. More than 3,700 taramea have been collected so far.
Research
Great white sharks might change their colour when hunting prey. Researchers conducted experiments off of South Africa using a specially designed colour board with white, grey and black panels. Each shark was photographed as it jumped out of the water at the panels, with the experiment being repeated throughout the day. One particular shark appeared to be both dark grey and a much lighter grey at different times. The results were verified using computer software to correct for variables such as weather, light levels and camera settings. While the research has not yet been validated and published in a scientific journal, experts are still excited about the results.
Managing habitats for the benefit of wildlife can often contradict climate priorities. In the Summer 2022 issue of Conservation Land Management (CLM), Malcolm Ausden and Rob Field describe how different habitats and their maintenance impact the climate, and highlight the management practices that provide the greatest climate benefits. Here you can read a summary of the article.
Quantifying the impacts of habitat management on the climate
The influence of different habitats and their management on the climate can be measured by estimating the net flux of the most important greenhouse gases (GHGs): carbon dioxide, methane and nitrous oxide. The contribution of the latter two is usually expressed in terms of the amount of CO2 needed to produce the same level of warming (tonnes of CO2 equivalent; t CO2e), as determined by global warming potential (GWP) of the different gases. A positive GWP indicates a positive warming effect, whereas a negative GWP shows a cooling effect. GWP values are usually expressed in comparison to the warming potential of CO2 over 100 years.
The effects of conservation land management on GHG flux
In the full CLM article, the authors describe the GHG flux of the main types of habitats in Britain, and how this is affected by conservation management. The habitats included are listed below, starting with those that produce the greatest overall warming effect on the climate, and finishing with those that have a cooling effect.
Intensive arable on organic soil
Intensive grassland on organic soil
Eutrophic/mesotrophic open water
Lowland wet grassland on organic soil
Intensive arable on mineral soil (incl. emissions from farming operations)
Bare peat
Oligotrophic open water
Heather-dominated drained bog
Intensive arable on mineral soil (excl. emissions from farming operations)
Lowland and upland heathland
Unimproved low-input grassland (incl. LWG on mineral soil)
Near-natural bog
Improved grassland (excl. emissions from farming/livestock operations)
Near-natural fen
Mudflat
Conifer plantation on mineral soil (managed on a 55-year-rotation)
Saltmarsh
Dry broadleaved woodland (mean over first 100 years)
Wet woodland
Dry broadleaved woodland (mean over first 30 years)
Conifer plantations can have a cooling effect on the climate if grown on mineral soil and managed on a 55-year-rotation. Image by Andrew Arch via Flickr.
Intensive arable on organic soil (soils derived from peat) produces the biggest warming effect per unit area, as large quantities of CO2 are released via oxidation of dried-out peat that is repeatedly exposed during the cultivation process. The manufacture and use of nitrate fertilisers and the use of machinery also contributes to significant emissions of GHGs. At the other end of the spectrum is dry broadleaved woodland, particularly during the first 30 years after its establishment. The GHG flux of woodland fluctuates depending on its age, species composition, the density and growth rate of trees, and management. For unmanaged woodland, the net uptake of CO2 is low while trees are small, and planting of trees can even lead to a net release of CO2 as a result of soil disturbance. The rate of CO2 uptake increases during the main growth stage of the trees, slowing as they mature, although carbon does continue to accumulate in the soil.
Ways to benefit both the climate and wildlife
Conservation management can provide climate benefits either by reducing the amount of GHGs released into the atmosphere, or by actively removing them (i.e. carbon sequestration). For example, rewetting drained peatland reduces, and should eventually stop, the release of CO2 that occurs through the drying out and oxidation of peat. Although there is an initial release of methane after rewetting, accumulation of carbon in the peat will resume. The climate benefits per unit area of wet peatland are surprisingly low compared to some other types of habitat, but due to the large quantities of carbon stored within the vast expanse of peat in upland Britain, rewetting drained areas is an incredibly important measure to prevent the ongoing release of CO2, and will also provide a number of benefits for wildlife.
On organic soils used for arable, the greatest climate benefits per unit area come by creating wet woodland, as this prevents the oxidation of the peat and allows carbon to accumulate during tree growth. There are, however, limited opportunities to create new wet woodland on ex-arable organic soils and to keep them adequately saturated. The next best option is the creation of swamp/fen, which offers far greater climate benefits than agriculturally drained peat soils, even though the habitat itself has an overall GWP100 near to zero.
Swamp/fens offer far greater climate benefits than agriculturally drained peat soils. Image by Liz West via Flickr
The authors look at multiple management approaches and describe the climate benefits of different types of habitat restoration and creation. All the methods listed below are beneficial for the climate, and are ordered here by the magnitude of their cooling effect, from the least to the greatest.
Creating swamp/fen on ex-arable on mineral soil
Rewetting drained bog
Creating lowland wet grassland on ex-arable on mineral soil
Creating intertidal habitat on ex-arable on mineral soil
Establishing broadleaved woodland on ex-arable on mineral soil
Creating lowland wet grassland on drained grassland on organic soil
Creating swamp/fen on drained grassland on organic soil
Creating lowland wet grassland on ex-arable on organic soil
Creating swamp/fen on ex-arable on organic soil
Creating wet woodland on ex-arable on organic soil
A large aspect of the management of semi-natural habitats involves cutting and clearing vegetation in order to maintain a particular vegetation structure and to slow or reverse succession. But this means that the amount of carbon accumulated in the soil and vegetation is reduced. In addition, the removal of vegetation is often carried out by using domestic livestock, which release large quantities of methane, by machinery, which is often powered by fossil fuel or biofuel and releases CO2, or by burning, which also releases CO2.
Domestic livestock release large quantities of methane. Image by USDA NRCS Montana via Flickr
But there are changes that can be made to management that can help contribute to a habitat’s cooling effect. For example, the amount of vegetation that is removed from a site can be reduced to allow more carbon to be stored in the vegetation or soil. In some instances this can mean allowing a site, such as a swamp/fen, to develop into woodland or scrub. This can contradict conservation goals where maintaining an early successional habitat is the priority, but can be an option for sites that are currently poor for wildlife.
Another option is to change the method used to clear the vegetation. One way that this can be achieved is by swapping livestock for grazers that release less methane per quantity of vegetation removed. Ponies, for example, produce much lower levels of methane compared to cattle and sheep, although before changing the type of livestock it is important to understand that different livestock have different effects on vegetation structure and composition. In the full article, the authors explore this and other changes that site owners can make to increase the cooling effect of different habitats and their management.
It can be difficult for conservationists and land managers to know how to best manage a site in the interest of both nature conservation and the climate, and in many cases there are trade-offs between maximising the benefits for the two. But as the article demonstrates, there are restoration approaches that can be used that provide significant climate and conservation benefits, and it is helpful to consider and quantify the net flux of GHGs before implementing any changes to conservation management plans.
Other articles featured in the Summer 2022 issue include:
Saltmarsh restoration through flash re-creation
Measuring conservation success on farmland
Viewpoint: Dams without beavers: could beaver dam analogues yield benefits in the UK?
In this and every issue you can expect to see Briefing, keeping you up to date with the latest training courses, events and publications, and On the ground which provides helpful tips or updates on products relevant to land management. Other features that regularly appear in CLM include Viewpoint, a similar length to our main articles, but here authors can voice their own views on various conservation issues, and Review, which can include letters from readers or updates from our authors.
CLM is published four times a year in March, June, September and December, and is available by subscription only, delivered straight to your door. Subscriptions start from £22 per year. Previous back issues are also available to purchase individually (subject to availability).
If you are involved in a conservation project and think your experiences could be useful to other practitioners, we would love to hear from you. If you are interested in writing for CLM feel free to contact us – we will be happy to discuss your ideas with you.
