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.
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.
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.
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.
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.
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.
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.
British Wildlife is a subscription-only magazine published eight times per year: visit www.britishwildlife.com or email firstname.lastname@example.org 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.
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.
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.
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.
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 Batbox Baton is an economical and user-friendly bat detector ideal for newcomers to bat detecting and bat detecting enthusiasts alike. The Baton is perhaps one of the most simple and easy-to-use bat detectors on the market, so simple that it can be operated with a single button. With simplicity often comes sacrifice, but not in the case of the Baton. This device uses technology called frequency division which enables the user to monitor all ultrasonic frequencies between 20kHz and 120kHz at once by dividing the frequency by a factor of 10. If a bat calls at 50kHz, for example, a 5kHz form will be played through the speakers. This means no tuning is required and the user is not at risk of missing any bats by being tuned to the wrong frequency.
We took out a Batbox Baton to a rural lake in Hampshire at dusk on a dry August evening. The detector comes preloaded with a battery, and with a flick of the single On/Off button we were listening to bat calls in a matter of seconds. The detector is extremely lightweight, ergonomic and compact, making it easy to carry into the field. The calls of (what we believe were) Soprano Pipistrelles were divided down to an audible frequency and we could hear multiple individuals calling and hunting above us. It is worth noting that species identification can be more difficult without a frequency display screen, especially if the user has less experience in hearing calls in frequency division or if they are unable to compare with other bat calls. We found the Baton a very useful tool for listening to bats for pleasure and the lack of a screen or tuning dials means you can focus your eyes above and watch the bats as they fly and hunt.
Should the user wish to get a bit more out of their bat detecting experience, however, the Baton does provide options. The Baton has a ‘Line Out’ socket, and when connected to a laptop with a soundcard via a stereo lead, and used in conjunction with the free BatScan analysis software compatible with Windows only, real-time sonograms can be viewed in the field allowing detailed analysis and species identification.
The Baton’s Line Out socket can also be used with a digital audio recorder, such as a H1n Handy Recorder, and calls can be recorded for future analysis using the same BatScan software. It should be noted that if the user wishes to listen to calls through headphones, this cannot be done through the detector itself but only via the audio recorder. The use of a recorder and further analysis with BatScan software allows the user to gain a detailed understanding of call structure and species identification, and further their enjoyment of bat detecting.
Whether you have been enjoying bat detecting for years, or you are just looking to start out, the Batbox Baton will have something for you. It is an economic and versatile option that we would not hesitate to recommend.
The Batbox Baton Bat Detector can be found here. Our full range of bat detectors can be found here.
If you have any questions about our range or would like some advice on the right product for you then please contact us via email at email@example.com or phone on 01803 865913.
Butterfly Conservation opened the Big Butterfly Count between 15th July and 7th August this year. This annual initiative sees citizen scientists taking to their gardens, local parks and verges, or heading out into the countryside to spend fifteen minutes counting the butterflies and moths in their chosen patch.
At the time of writing (15th August) the results on the 2022 Big Butterfly Count page state an accumulation of just shy of 95,000 counts recorded by approximately 63,400 participants. Most counts were submitted from the UK but there was a scattering of submissions from elsewhere in the world. It’s a lower participation count than last year, but there’s still time to submit any counts you took between 15th July and 7th August at: https://bigbutterflycount.butterfly-conservation.org/map
The results from the 2021 Big Butterfly Count suggested a continued decline of the overall number of butterflies across the UK and prompted some sobering thoughts on the diminishing appearances of these beautiful, remarkable and vital members of our ecosystem. “76% of butterflies have declined in abundance in distribution since 1976” heads one article on the Butterfly Conservation website, then goes on to state that “We may be the last generation to enjoy butterflies and moths in abundance.”
Some interesting results from the 2021 Big Butterfly Count were increases in the recorded numbers of some species such as Meadow Brown (Maniola jurtina) (33%), Ringlet (Aphantopus hyperantus) (81%) and Six-spot Burnet (Zygaena filipendulae) (42%) and a whopping increase of 213% from 2020 for the Marbled White (Melanargia galathea)!
It’s hard to imagine that 2022 has been more favourable for the UK’s Lepidoptera. A prolonged winter of record-breaking storms that rattled the country was followed by low temperatures through spring that gave way in a burst to record-breaking heat, parching the soil for weeks on end and plunging us into drought and sporadic wildfires by the time the Big Butterfly Count came around.
For one of my counts I took a lunch break trip to a local parkland meadow under a heavy humid sky where the grasses, thistles and cow parsley flowers have been allowed to grow all summer long. Allotments run along one field edge and private gardens with a variety of growing styles along the other. In my allocated 15 minute count a single Large White (Pieris brassicae) slipped past in a hurry, over the wall and away.
A second count along a hedge by the local river bank was a little more fruitful, sporting three Gatekeepers (Pryonia tithonus), one Meadow Brown (Maniola jurtina) and five Ringlets (Aphantopus hyperantus) all skipping along the spent bramble flowers and sunning themselves on the leaves.
Elsewhere within the NHBS team, counts were taken by Hana, Catherine and Sabine who spotted the following species in their chosen locations:
1 x Speckled Wood (Pararge aegeria)
1 x Red Admiral (Vanessa atalanta)
1 x Jersey Tiger Moth (Euplagia quadripunctaria)
7 x Large White (Pieris brassicae)
3 x Speckled Wood (Pararge aegeria)
2 x Red Admiral (Vanessa atalanta)
2 x Gatekeeper (Pryonia tithonus)
1 x Holly Blue (Celastrina argiolus)
1 x Comma (Polygonia c-album)
2 x Small White (Pieris rapae)
2 x Small Copper (Lycaena phlaeas)
1 x Red Admiral (Vanessa atalanta)
There’s some interesting reading on the Butterfly Conservation website on their strategy to save and support the UK’s butterfly and moth populations here and a useful guide to ways that you can directly get involved and help out here.
The current top 5 Butterflies recorded in the 2022 Big Butterfly Count are as follows:
Large White (Pieris brassicae)
Gatekeeper (Pryonia tithonus)
Small White (Pieris rapae)
Meadow Brown (Maniola jurtina)
Red Admiral (Vanessa atalanta)
NHBS sells a wide variety of helpful guides to assist in butterfly identification all around the world – some great ones to get you started in the UK include:
Britain’s Butterflies:A Field Guide to the Butterflies of Great Britain and Ireland Flexibound | 2020 £12.50£17.99
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!
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 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.