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You are here: Home / 2022 / Archives for April 2022

Archives for April 2022

PAN UK: Pesticide-Free London Campaign

April 28, 2022 by admin

There is a growing groundswell of support for a pesticide-free London among the capital’s decision-makers and residents.

One-third of London’s 32 Boroughs have already phased out, or significantly reduced, their use of pesticides while others have commitments in place to take action. London is already one of the greenest cities in the world and the first to be designated a National Park City.

Right now, there is an unprecedented window of opportunity to make the whole of London pesticide-free. By phasing out unnecessary pesticide use, we can make the city greener and support urban biodiversity, as well as the health of those who live, work, study and play in the capital. It’s high time that London followed the example of other major cities like Paris, Toronto and New York by banning pesticides from public spaces.

A pesticide-free London is in our sights and by working together we can secure a healthier and more sustainable future for both people and wildlife.

PAN UK sent Freedom of Information requests to all thirty-two London borough councils in September and October 2021. Thirty-one councils responded (all but Ealing Council). Read a summary of their findings here and find out about the pesticides being used in your borough by clicking on the map on PAN UK’s campaign page here. 

 

What can you do to help?

There are lots of ways to make a difference in your borough which you can adapt depending on the amount of time you have available. There are tonnes of resources and ideas on PAN UK’s campaign page here.

 

 

Filed Under: Campaigns Tagged With: Borough Councils, London, National Park City, PAN UK, Pesticide, Pesticide-Free, pesticides

What our animals are doing this month …

April 26, 2022 by admin

Springtime is a great time of year to try and spot a common lizard – so why not give it a go? Adult lizards emerge from their hibernation sites in early spring, with mating taking place around April/May. Females incubate their eggs inside their bodies and give birth to up to 11 live young later in the summer.

These fascinating reptiles are usually up to 15cm long and are often mistaken for newts (even though the common lizard has scaly skin rather than smooth skin). They are usually a brown colour, but they can be yellow, green or even black! Common lizards also have a pattern of spots or stripes down their back with males having a yellow or orange belly with black spots and females having a pale, unspotted belly.

This species is widespread throughout the UK, including Ireland, but can be quite hard to spot! They are agile and fast and will move away quickly if they have spotted you, so you will have to be extra quiet if you want to see one. Try looking further ahead rather than right in front of you. Download our ‘Surveying for Reptiles’ booklet for free from our website for more tips.

Where to spot them: The common lizard is mainly a ground dweller, but you can sometimes see them climbing. They like sunny, dry, exposed areas near dense cover so they can hide if they need to. Their favourite meals are worms, slugs, and insects – yum!

They also have the ability to lose their tails if being chased by a predator! How clever is that? They will be able to regrow their tail, but it is never as good as the original.

Living in Scotland and want to try and spot one? Flanders Moss near Stirling is a very good place to start!

Always remember to record your amphibian and reptile sightings on our FREE Dragon Finder app. All of the data collected is sent to the National Biodiversity Network Atlas. You can download the app here.

Filed Under: What our animals are doing this month Tagged With: Citizen Science, common lizard, lizard, mating, reptile, reptiles, spring, surveying for reptiles, wildlife recording, wildlife spotting

Can frogs, salamanders and lizards show us the way to limb regeneration?

April 26, 2022 by Roger Downie

Roger Downie

Froglife and University of Glasgow

Limb loss in humans is a very significant source of disability and distress. One estimate is that in the USA alone, 3.6 million people will be affected by 2050, as a result of war and other traumatic injuries, or after diabetes-related amputation (Ziegler-Graham et al. 2008). There are two possible routes to the treatment of these losses. Until recently, the most hopeful way forward was advances in prosthetic limb development, related to robotic and micro-electronic engineering progress. Encouraging regeneration of the lost limb seemed less likely, despite many years of research. This is because organ regeneration in mammals is extremely limited in nature. However, recent work based at Tufts University in the USA, using the African clawed frog Xenopus laevis, suggests that limb regeneration in mammals could be stimulated with the right interventions (Murugan et al. 2022).

African Clawed Frog

The ability to repair tissue damage is very widespread in the animal kingdom. In ourselves, the most obvious example is wound healing, with a complex sequence of events following an injury: local cessation of blood flow; blood clotting and formation of a scab to prevent entry of micro-organisms; mobilisation of surrounding cells to close the wound; tissue remodelling below the skin to tidy up the damage, sometimes involving formation of scar tissue. However, some animals have the capacity to replace complete and functional organs if they are lost. In amphibians and reptiles, this capability has an odd distribution.

Some species of lizards show autotomy, the deliberate loss of part or all of the tail in response to predator attack (autotomy also happens elsewhere in the animal kingdom: starfish, stick insects etc.). In these lizards, muscles in the tail on the body side contract, severing a line of weakness built into the vertebrae, and the predator is left with the twitching end of the tail, while the rest of the lizard escapes. The tail stump then heals, and the tail regenerates, but not as before. The regenerate is mis-shapen and its skeletal core is a stiff rod of tissue, rather than a set of vertebrae. If the lizard is attacked again, autotomy can only occur in the part of the tail containing the original structures. The costs and benefits of tail autotomy in lizards are finely balanced, and this ability has been lost and evolved many times in different lineages (Clause and Capaldi 2006). Where the tail is important in balance, as in fast-running species, or in social signalling, as a sign of quality as in Uta species (Fox 1998), autotomy tends to be rare or does not occur at all. Cooper et al. (2004) showed that selection related to predation pressure could influence the occurrence of autotomy in different populations of a single lizard species.

In newts and salamanders, adults can regenerate a range of complex organs: parts of the eye, brain, and heart, as well as limbs and tail. This does not involve autotomy, and unlike the case of lizard tails, regeneration results in the re-formation of a normal, functional limb or tail. Limb regeneration follows an orderly sequence: closing of the wound is followed by the formation of a ‘blastema’- a mass of tissue with the characteristics of tissue at the distal end of an embryonic developing limb. Somehow, the blastema ‘knows’ how much of the limb has been lost, and it reforms only the missing elements in order, from proximal to distal ends. As the process progresses, nerves grow into the regenerate, and these provide signalling molecules essential for full regeneration. The ability to regenerate limbs is somewhat variable between species, with larger species and individuals generally having less regenerative capacity than smaller ones (Joven et al. 2019).

In frogs and toads, regeneration of larval tails and early-stage limb buds occurs, but limb regeneration in adults hardly at all. In some families (pipids, discoglossids, hyperoliids), a blastema forms and a partial regenerate grows from the stump, a bit like the regenerated tails of lizards, but it never approaches the size and complexity of the original limb. In bufonids and ranids, wound healing occurs, but no regeneration at all (Scadding 1981). Mammals are like adult amphibians, with no limb regeneration at all.

This is where the new results from Murugan et al. are revelatory. After some years of technique development, they now report substantial hindlimb regeneration  in experimentally-amputated Xenopus laevis adults ( X. laevis has a long history as a laboratory species for biological research following its early 20th Century use in human pregnancy testing). The method involves applying a temporary ‘collar’ (called a ‘Biodome’) to the limb stump following amputation. The collar is made of silicone and silk fibres, impregnated with a solution containing a mix of five molecules known to act as signals during normal limb development (such as growth hormone and retinoic acid). It therefore provides a moist environment for the stump tissue, including limb development molecules that would not normally be present there in damaged adult Xenopus limbs. The collars were left in place for only 24 hours, then removed, and the frogs then followed for 18 months to assess how well the amputated limbs regenerated. After decades of failure in such experiments, the results were spectacular.

BioDome cap. Photo: Nirosha Murugan

The regenerates formed went well beyond the mis-shapen spikes usually formed by Xenopus stumps. There was long-term growth, including formation of bones and other normal tissues, neuromuscular repair so that the limbs could move, and the formation of digit-like projections at the distal ends: the animals were able to use their repaired limbs for more or less normal movements. Murugan et al. comment that while regeneration was not perfect in their experiment, the set-up provides considerable scope for alteration of the details: the mix and concentration of the signalling molecules, the duration of their application; also, the possible addition of electrical stimulation, which has shown some positive effects in other experiments. The authors are hopeful that, if regeneration can be stimulated in Xenopus, similar methods may work for mammals, including humans.

The occurrence and distribution of organ regeneration has long intrigued biologists (Bely 2010). For example, why should complete regeneration occur in newt and salamander adults, but not at all in frogs and toads? One theory concerns the period of impairment while the limb is regenerating, which can take months. Newt locomotion can remain effective in the absence of a functional limb (in many species, the limbs are greatly reduced and even absent in some), whereas the absence of a frog hindlimb for some months would be disastrous. The argument from this is that limb regeneration in frogs would be too slow to be effective, and therefore that it does not occur. This argument can be extended to mammals: the high demand for food in warm-blooded animals means that a period of immobility while a limb regenerates would not be useful (Elder 1979). Most discussion of limb regeneration assumes that the benefit follows limb loss after predation, as in lizards, but there are very few studies investigating the ecological role of regeneration in newts and salamanders.  

Finally, a comment on ethics. Those opposed to any animal experimentation will not approve of Murugan et al.’s studies. Those with a more utilitarian outlook, will hope that the discomfort and death of a hundred or so Xenopus will lead eventually to new treatments that could benefit millions of people (and even some other animals). Those who prioritise animal welfare will study the conditions under which the Xenopus lived and look to see that the experimental protocols minimised any pain and discomfort. However, there is another ethical aspect: on behalf of Tufts University, where the experiments have been done, patents for the methodology have been applied for. I find it distressing that scientists should seek to make profit from advances in medical research, especially when it has been publicly funded. The notion that, in the future, victims of war should have to pay a royalty to Tufts so that their limbs can be repaired, is distasteful. But then we are all used these days to noticing that some companies have done very well financially out of the Covid pandemic.

 

References

Bely, A.E. 2010. Evolution of animal regeneration: re-emergence of a field. Trends in Ecology and Evolution 25, 161-170.

Clause, A.R. and Capaldi, E.A. 2006. Caudal autotomy and regeneration in lizards. Journal of Experimental Zoology 305A, 965-973.

Cooper, W.E. et al. 2004. Ease and effectiveness of costly autotomy vary with predation intensity among lizard populations. Journal of Zoology 262, 243-255.

Elder, D. 1979. Why is regeneration capacity restricted in higher organisms?  Journal of Theoretical Biology 81, 563-568.

Joven, A. et al.   2019. Model systems for regeneration: salamanders. Development 146, dev167700.

Murugan, N.J. et al.  2022. Acute multidrug delivery via a wearable bioreactor facilitates long-term limb regeneration and functional recovery in adult Xenopus laevis. Science Advances 8 (4).

Scadding, S.R. 1981. Limb regeneration in adult amphibia. Canadian Journal of Zoology 59, 34-46.

Ziegler-Graham et al. 2008. Estimating the prevalence of limb loss in the United States, 2005-2050. Archives of Physical Medicine and Rehabilitation 89, 422-429.

Filed Under: Croaking Science Tagged With: frogs, limb, limb regeneration, limbs, lizards, salamaders, Tufts University, USA

Zero Hour

April 14, 2022 by admin

It’s time to act for climate and nature! 

Zero Hour is the campaign group behind the Climate and Ecological Emergency Bill, or ‘CEE Bill’. The CEE Bill was first developed with members of the successful ‘Big Ask’ campaign (a Friends of the Earth initiative which led to the Climate Change Act 2008), Power for People and with contributions from eminent scientists, academics and lawyers. The campaign for the CEE Bill launched in August 2020, with its introduction to Parliament in September 2020. The updated CEE Bill was introduced in Parliament in June 2021.

The CEE Bill has received backing from a wide range of supporters, including Froglife, and from different fields including Ben Fogle, Kumi Naidoo (Director, Greenpeace International, 2009-16); musician, Thom Yorke; environmentalist, Bill McKibben; Volans co-founder, John Elkington and actor-playwright Sir Mark Rylance. For a full list of supporters, you can head to Zero Hour’s Allies and Supporters page. 

What can you do? 

Time is running out for climate and nature and we need to get the Climate and Ecological Emergency bill through in a fraction of that time, so it’s time for MPs, councils, organisations and individuals to step up! The more support, the more pressure there will be on the government to take the Bill into law. And for that to happen we need as many campaigners, both as individuals and organisations to declare their support for the CEE Bill. 

Declare your support here. 

Find more information on the Zero Hour campaign here. 

Filed Under: Campaigns Tagged With: CEE Bill, climate, Climate and Ecological Emergency, Nature, time to act, Zero Hour

A brief introduction to Marsh Frogs

April 11, 2022 by admin

Froglife volunteer, Victoria L, has taken the time to look into Marsh Frogs, one of the non-native frog species that you could come across in ponds and ditches across the UK, Most commonly spotted in South-eastern areas of England. 

What are Marsh Frogs and where do they come from?

Marsh frogs (Pelophylax ridibundus) are a species of frog which are native to continental Europe and Western Asia. They are not a native species in the UK and were introduced in the 1930’s from eastern Europe. They are Europe’s largest native frog species, growing up to 15cm in length. In the UK, they are most frequently found in the Southeast of England, particularly in marshland areas. 

Where do Marsh Frogs like to live?

Marsh Frogs are most prominent in the South-east of England due to having been imported from Hungary in 1935 and introduced to the Walland Marsh in Kent, already making it the main location of the species in the UK. Marsh Frogs prefer to spend most of their time either at the edge of or inside a body of water. They have an affinity towards wet, humid habitats such as lakes, ponds, and rivers. When they are not in the depths of these water bodies, they bathe in the sun.

This aquatic preference makes Marsh Frogs differ from other species, like the common frog, which travel around the landscape without much need to be in a constantly wet environment.

What makes Marsh Frogs unique?

Marsh Frogs may seem like any ‘typical’ frog, yet they have some unique features in plain sight. Marsh Frogs are bigger than the usual frog, usually being 13cm long but have the potential to reach 15cm. This contrasts with other frog species which are usually smaller, around 8cm. Another special identification detail about Marsh Frogs is that males have two grey vocal sacs on either side of their head which produce their call. Marsh Frogs have an interesting call which sounds like a cackle or a laugh, which can be produced by both females and males. Their calls travels far and can be used to attract mates.

Marsh Frogs have the ability to have hybrid offspring with other frog species, the green frog group. They can also easily adapt, for example them being able to survive in salt marshes.

Although Marsh Frogs are not native to the UK, their close relative, the pool frog, is. They belong to a group called ‘Green Frogs’ along with their hybrid, the edible frog.

What do Marsh Frogs look like?

They have large heads, males having the two grey vocal sacs on either side. Marsh Frogs also have textured skin along with folds on either side of their body. They come in a variety of colours, be it green, brown or grey.

What is the diet of Marsh Frogs?

Like any other frog, Marsh Frogs consume insects such as worms and spiders. Yet, they may also consume other frogs and even mice, contributing to the threat of native species in the UK.

What impact do Marsh Frogs have in the UK?

With Kent having a rise in the invasive, non-native, Marsh Frog population there has been a simultaneous decline in the populations of common frogs and native newts. Studies have shown that this is likely due to the Marsh Frog species preying on the common frogs and native newts while also bringing them diseases such as chytridiomycosis which they carry and is a threat to native species.

Other studies have shown a decrease in common frogs occurring in habitats which do not contain Marsh Frogs. This is likely due to the changes in habitats caused by pollution and climate change. This has led researchers to believe that the cause of this decline in common frogs is caused by both factors, which also affects other native species as well.

The affect of climate change on Marsh Frogs and other Herpetofauna:

Climate change also plays an important role on the future of Marsh Frogs and UK native frog species. Reptiles and amphibians are sensitive to the changes in precipitation of their environment, being two animal groups which are highly affected by climate change. As climate change and other severe events increase, research and monitoring of vulnerable species become even more important to drive effective conservation efforts.

Warmer temperatures have an unforeseen affect on herpetofauna, impacting their behaviour, reproduction and distribution traits. With climate change and global warming, this is currently affecting them.

Read more about Marsh Frogs.

REFERENCES:

https://insideecology.com/2018/01/23/invasive-non-native-species-uk-marsh-frog/

https://www.liebertpub.com/doi/pdf/10.1089/scc.2020.0027

Filed Under: Species Tagged With: amphibian, Amphibians, chytrid, climate change, frogs, green frogs, Hungary, invasive, marsh frogs, non-native, South-East England

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