Challenges Of Managing Red Squirrel Populations Biology Essay
The aim of this essay is to investigate the conservation of red squirrels in the Formby Nature Reserve and to see what impacts the management processes have on the red squirrel populations and whether they're successful in increasing the populations of red squirrels and what strategies are effective in the management of red squirrels. Ultimately this essay will attempt to research "Can Red squirrels be effectively managed in the Formby Nature Reserve?"
My interest in this topic stems from people not paying as much attention as they once did to red squirrels as people are becoming less and less concerned when it comes to nature and the environment, which is quite distressing as they are missing out on some incredible sightings. It's not just red squirrels that are becoming extinct, but rather a whole range of animals that are slowly being wiped out. According to recent findings, there are more than 1000 species that are endangered worldwide. All of these threatened animals require careful management in order to survive.
There are estimated to be 211,000 red squirrels left in Britain, less than 1,000 of which are located in the Lake District alone and about 120,000 in Scotland(see map 1.2 and 1.3 on page 4). This may seem like a large population but in comparison to the grey squirrel population of over 2.5 million, the 140,000 is starting to look quite insignificant.
There are many reasons for the decline of the Red Squirrel in Britain; this includes:
The Red Squirrel still occurs throughout most of Lancashire and Cumbria with populations adding up to 140,000, with the strongest populations in the north of Cumbria (see map 1.2). The main boundary where the two species are directly competing is in south Cumbria, to the south of Grasmere. Grey squirrels are also moving into Cumbria, supposedly from Scotland.
As part of our geography IB course, we looked at the management of fragile ecosystems and biodiversity in relation to animal populations. Due to my caring and compassionate nature, I have always loved animals and seeing stunning creatures becoming extinct is heart-breaking which is the reason for my choice of topic alongside wanting to understand the importance of management strategies. This topic is very interesting to me and motivates me considerably to complete it.
In order to narrow my essay question, I had to be realistic to which endangered species I could use and find out about more. Because I live so close to the Lake District, I thought it would be logical to take advantage of that and investigate the red squirrel in this area.
Location of Red Squirrels
The red squirrel is found all over Europe and parts of Russia and Asia (as shown above) which is also called Eurasia. The locations of the red squirrel in the United Kingdom are mostly in the northern region (see figure 1.2). This is most likely because there are many more wooded areas where the red squirrels can breed and can get access to a consistent and diverse food supply (figure 1.3). There food consumption consists of tree seeds, nuts, berries, cones, buds, shoots, flowers, lichen, fungi and occasionally insects. The seeds which are normally consumed are the seeds inside pine cones which originate from conifer trees indicating that the majority of red squirrel populations are located near coniferous woodland.
As we can see from the map (figure 1.3) the majority of conifers are in the northern regions verifying that the map above is, in fact, genuine.
History of the Red Squirrel
The oldest red squirrel that is known to us was actually a tree squirrel fossil. This was formed approximately 34 million years ago and is called Protosciurus. The squirrels nowadays, don't look very different from their older ancestors, there are however, many more types of species with an approximate value of 267 species around the world.
The word squirrel comes from the Greek word "Skiouros". "Skia" means shade and "oura" means tail. Therefore "skiouros" means "he who sits in the shadow of his own tail". Centuries later the French developed the noun "esquirrel", then the English decided to form squirrel from this, which is why we they are called squirrels today.
The first indication of red squirrels being alive was about 10,000 years ago, after the most recent ice age, when the bridge between Britain and Europe disappeared. This is most likely why red squirrels are found in both Britain and Eurasia as we once shared land, which the red squirrel formerly lived on.
Due to wars in the fifteenth and sixteenth centuries, the red squirrel population declined because of timber felling needed for the ships in the wars. However, later on in the nineteenth century, trees were being replanted because of an initiative that was written to replace the trees that were lost through industry which, in effect, attracted many of the red squirrels back to the land.
The decline in the red squirrel populations and the need to understand its ecology and conservation necessities led to an increase in primary research during the 1970's and 1980's and obviously the amount of research has increased hugely through to present day.
Previously, red squirrel conservation efforts have involved grey squirrel control at national or regional level. In the last two to three years, mainly in the north of England, organisations have been the focussing on a considerable amount of red squirrel research and conservation work that has taken in a number of different approaches. In addition to the nature reserves that have been put in place, there has been conservation work targeted at the local and regional levels.
Organisations that manage red squirrels:
It has been estimated that the red squirrel could, in fact, become extinct from the whole of England in less than fifteen years unless certain precautions are taken.
Cumbria Biodiversity Partnership
All these organisations form a Joint Nature Conservation Committee that works towards increasing red squirrel populations in the whole country.
Yorkshire Dales National Park Authority
North West Red Alert
Landowners and managers
Sedbergh Red Squirrel Group
All of these organisations work together to help increase the populations of red squirrels by implementing a Species Action Plan that aims 'to preserve the current population and range of red squirrels within the Cumbrian National Parks'. The overall aim and the strategies are made from this. The objectives that they have to see this Action plan through are to implement the Cumbria Biodiversity Action Plan for red squirrels in the Cumbrian National Parks by 2010. In addition to this main objective, they have many general objectives. These include:
Raising public awareness about red squirrels and red squirrel conservation. This could become possible through creating a red squirrel group, which could possibly cause more reports of red squirrel sightings and encourage more locals to look and perhaps even invest money in conservation schemes.
Encourage positive conservation management for red squirrels in areas of suitable habitat.
Reduce the threat from grey squirrels to red squirrel populations.
Reintroduce red squirrels into areas where they previously existed and where the ecosystem can be managed effectively.
There is, in fact, legal protection for the red squirrels which states that:
"The Red Squirrel is fully protected by the Wildlife and Countryside Act 1981 (as amended), and is listed in Appendix III of the Bern Convention. At least seven Sites of Special Scientific Interest and three National Nature Reserves support Red Squirrel in Cumbria."
Red Squirrel Threats
In order to understand how we can manage and increase the red squirrel populations to a healthy level, we must first evaluate why their numbers are decreasing in the first place.
The native red squirrel has become almost extinct from a vast majority of the country. This is mainly because of the spread of the American grey squirrel which is able to live better in broadleaved woodland areas, although disease and other contributing factors may have played a part, the grey squirrel, in my opinion, is the main reason for the decline in red squirrels. Grey squirrels were introduced into the UK in the late 1800's.
The red squirrel was once the only species of squirrel in the UK. But once the grey squirrels were introduced, red squirrels started decreasing in numbers. The red squirrel is much smaller and thinner than the grey, which could be the reason for the dominance of the grey squirrel as it's more adapted to its habitat. Because grey squirrels are more adapted to broadleaved woodlands, it is making them extremely efficient when it comes to hunting and getting into food such as seeds and nuts. The grey squirrel is adapted to being so efficient by being able to eat more compared to the red squirrel as they are able to easily digest acorns, where the red squirrel cannot. It has also been suggested that due to their larger size, grey squirrels may be more likely to survive during periods of severe weather.
If there is a large amount of competition in a certain place like South Cumbria and North Lancashire where there are increasing numbers of broadleaved trees, red squirrels are less likely to colonise there as the demand for food by each species would be great. This is putting enormous strain on the environment and surroundings and the resources that it supplies.
As we know, red squirrels are being replaced by grey squirrels. However, this isn't just because grey squirrels are better adapted for their surroundings, but also because of diseases called parapox virus and coccidiosis. Both of these are known for the common cause of death in red squirrels. There have been cases reported that grey squirrels in North America have caught the virus which leads us to consider the possibility that the virus originates from grey squirrels but are only carriers of the disease. Once the disease is passed onto red squirrels, it causes the majority of them to die. The persistent infection is due to low antibody occurrence in the red squirrels.
Not only do grey squirrels intake more food and transmit diseases but also compete by just interfering with the lives of the red squirrels. For example, the male grey squirrels occasionally detect the scent of the female red squirrels mistaking it for a grey squirrels scent as both species have similar pheromones, this then tempts the male grey squirrel to follow the route of the scent and try unsuccessfully to enter the dreys of the female red squirrels.This whole occurrence is disrupting the male red squirrel chases as red squirrels tend to avoid grey squirrels, therefore the male red squirrels don't mate as frequently.
It is unknown why red squirrels tend to avoid grey squirrels. This passive avoidance of grey squirrels by reds means that whenever a grey squirrel is nearby the red squirrel will not go near. For example, if a grey was near a food hopper, the red squirrel would make no attempt to get access to the food source whilst the grey was present. In my opinion, I would have thought that if the red were agitated being near the grey squirrels, surely it is due to some sort of aggression or viscous attacks that had previously happened between them. However, there has been no scientific evidence to suggest that grey squirrels have been attacking red squirrels. But if there were to be violence between the two species, that could possibly be another reason for the red squirrels being driven out by the grey squirrels.
Habitat Fragmentation, the subdividing of a continuous habitat into smaller, more isolated pieces of land, is considered a major threat to the survival of red squirrels and its surrounding ecosystem. By dividing the habitats of natural populations, the biological diversity of the original habitat is declining. This is possibly due to changes in food availability, predation pressure, microclimate, or possible because of lack of genetic variation.
As mentioned above, lack of genetic variation is increasing the chances of causing local distinction as there is a strong decrease in the immigration-rate. In the short term, loss of genetic variation, which is could possibly be caused by inbreeding, can lead to a decline in reproductive traits such as fertility and litter size.
Woodland fragmentation decreases dispersal rates, however, red squirrels usually use 'stepping stone' patches to travel long distances through a fragmented habitat as red squirrels aim to avoid crossing open areas during dispersal movements if possible.
There have been cases where conservation organisations have grown large conifer forests in order to connect two individual forests. This is called Habitat 'Defragmentation'. An example of this is actually where the Cumbrian and Scottish forests were combined. This 'defragmentation' of the landscape has resulted in considerable genetic mixing of Scottish and Cumbrian genes in squirrel populations up to 100 kilometres from the site of the new forest.
Linking to the idea of habitat fragmentation, the forests that are being fragmented are being destroyed meaning that the amount of woodland present in the whole of the UK is lessening everyday as it is being removed due to the construction of roads and buildings which increase the chances that the red squirrels die because of road accidents. It is because of the red squirrel road killings that signs have been put in place stating that there are red squirrels present reducing the chances that the red squirrels are killed (Figure 1.4).
As we proceed into the future we are thinking of more and more advanced ideas to aid us in our day-to-day life. Governments believe that this will happen by becoming more industrialised so are therefore constructing more roads, buildings, and sometimes even just basic farm land for new crops, etc. However, the only place for this to happen, is where woodland is located increasing the rate of deforestation which is reducing the habitable forest for the red squirrels.
As well as these previous threats, the red squirrel is also at threat from predation. There are many potential predators of red squirrels in the UK. These include: the goshawk, buzzard, owls, and the pine marten. Pine martens, in particular, are usually thought of as the main predator of red squirrels as it is able to chase the red squirrel through the treetops, using its claws for climbing trees and its tail for agility and balance. It has been said in a small village in the north that as pine martens increased in numbers in that certain village then the resulting change was that the red squirrel population in that village decreased most likely due to the pine martens.
Red Squirrel Numbers
During my investigation, I emailed Formby Nature Reserve in order to collect some data from the Lancashire Wildlife Trust. Unfortunately, this is second hand data as I am only a sixth form student that has limited resources and insufficient time to collect a good range of data needed for this investigation. However, I trust that the researchers at Formby Nature Reserve have collected their data using correct and accurate procedures. The data that I obtained is followed:
If we look at the 2010 data on all the graphs (figure 1.5, 1.6 and 1.7), we can confirm that red squirrel populations are increasing. When looking at the results, it was heartening to see that red squirrels had increased in numbers from 2009 with tiny numbers that reached 17 at most.
By looking at figure 1.5, the overall population size seems to have recovered from 2003 to 2008, where the numbers dramatically drop. This is because in 2008, the squirrelpox epidemic was beginning to take its hold and had more than halved in 2009. Formby pinewoods were the worst hit by the squirrelpox epidemic during 2008. The spring population index fell to an all time low in 2009 suggesting a loss of 85% of red squirrels since 2002. This decrease is very similar to that of autumn 2008 which suggested an 80% decrease in autumn numbers since 2002.
By looking at figure 1.6, we can see that mortality was low during winter 2009/10 despite the harsh weather conditions that year. The loss of around 10% of the population is good compared with all previous winters except that of 2003/04. The winters of 2006 and 2007 had a mortality of 25% before disease struck. However, when disease struck in 2008, the mortality was at 80% which the highest it's ever been.
By looking at figure 1.7, autumn numbers were higher than spring's in every year, as expected, except 2008 as most mortality occurs during the winter months. The average increase in numbers between spring and autumn during 2002-2007 was around 30%, falling to just 10% in 2007 when the virus was beginning to take hold. In comparison, numbers fell by 37% during 2008.
All data from:
Management in the Formby Nature Reserve
In order to manage red squirrel populations, they require certain conditions so that they are able to survive in that habitat. These conditions include having enough land so that hey are able to get a consistent source of food (between 2000 and 5000 hectares)and having the correct species of tree such as birch, rowan, ash, willow, aspen and alder which don't attract grey squirrels. These are the most important conditions in which red squirrel survival will most likely be greater. A mixture of different ages and different species of trees are the best hope for the long-term survival of red squirrels.
Red Squirrel Population
Declining or remnant
Less than 10 years
More than 10 years
Grey Squirrel Present?
Grey Squirrel Present?
Habitat improvement or maintenance
Concentrate on areas over 200 ha, ideally over 2000 ha, plus buffer zone
Retard or prevent grey colonisation
Targeted control of grey squirrels
Retard or prevent grey colonisation
Targeted control of grey squirrels
Consider Reintroduction with Habitat Management and Grey Control
National Importance: HIGH
National Importance: MEDIUM
National Importance: LOW
This, above, is a map showing the suggested priorities that should be made for conservation action.
Management by reducing Grey Squirrel Population
Reducing the population of grey squirrels is one way of potentially increasing the population of red squirrels but there are limited opportunities on how we are able to control the grey squirrels.
Regional and/or national removal of recognized grey squirrel populations is not possible but local control is sometimes a practical aim. Grey squirrels are very strategic and populations can quickly increase in size. The currently legal and recommended grey squirrel control methods in areas of red squirrels are shooting and live-capture cage trapping. Shooting may seem effective, but less than 20% of an established population is removed and reds may be taken by mistake. Furthermore, synchronized cage trapping can be successful at reducing the population by up to 90% and, as a result, slowing colonisation. However, to maintain this low population, constant labour-intensive control is needed. The level of reduction of grey populations required to benefit reds is still unknown.
I have discussed the elimination of grey squirrels only by killing and trapping. But there are much less harmful ways in which the population of grey squirrels can be reduced and this is by using immunocontraceptive vaccines that selectively inhibit female fecundity. This thereby causing the grey squirrels to become infertile and unable to produce young which reduces the population of grey squirrels in the area so that there is less competition for the red squirrels for food and resources, etc.
In my opinion, grey squirrels are the main for the dramatic decline in red squirrels as in 2008, an epidemic begun of squirrelpox virus which is carried by the greys. By killing, trapping or using immunocontraceptives on them, we can reduce the amount of competition and death. This strategy was implemented during the epidemic of squirrelpox in 2009, which we can see had an effect on the amounts of squirrel populations as we can see in figure 1.5. In 2008, there were only 17 red squirrels present in the Nature Reserve but with careful management by reducing grey squirrels in the area, the red squirrels grew by 40% to 42. Therefore, by reducing and managing the amounts of red squirrels, we can increase the chances of survival for the red squirrels.
Management by Translocation and Reintroduction
Translocation is the process of capturing, moving and releasing of the red squirrels into a habitat that would be better suited for them in order to increase the population size.
The reintroduction process is a type of translocation, where the red squirrels are captured, moved and released in an area where they previously inhabited which is another method used to increase population size.
Reintroduction is used for many things but here are some main aims of reintroducing species:
To create separate populations of endangered species. By doing this we are improving the species' chance of survival.
To return species which have been removed from illegal trade so they can no longer be hunted.
To repopulate areas where excessive poaching has removed many of the important species that were initially found there.
These are very complex and complicated process which require constant observation, if not then they are is a great possibility that the processes will fail, meaning that the red squirrels that were reintroduced or were relocated would have died for no progress with the investigation/ experiment.
In 2003/2004, Formby Nature Reserve decided that it would be best to multiply the sites in which they kept the red squirrels so that the populations could be further increased on two different sites. This is why there is a gradual increase in squirrel populations as there were many sites to which they breed red squirrels. With regard to the data, for every year, they added all the squirrels from each site to get an even bigger amount of red squirrels in that area.
Management by Community Engagement
If we get the community involved in red squirrel conservation, the amount of red squirrels that could potentially get saved is incredible. If we got the community to do something as simple as report a sighting of a red squirrel, organisations could help that squirrel in its own survival. The monitoring of both red and grey squirrels is essential in understanding how effective the conservations work that is being put into place is working. Also, if a civilian was to see a red squirrel and was to report it, organisations would be able to track the distribution of the species.
Part of community action is supplementary feeding. Supplementary feeding is where citizens can lay out food so that squirrels, preferably red squirrels, can have access to the food. This is so that the squirrels always have an ample supply of food and aren't dying of starvation. This is also done by red squirrel conservation organisations where they construct a feeder so that only red squirrels are able to get access to this food source. The food that is included in the feeder is normally food that will nourish the squirrels so that even they have a balanced diet that is full of nutrients. During the red squirrels breeding season, in spring and summer, cuttlefish bones are left so that mother squirrels are able to feed their kittens.
As for this management strategy, I believe that this is only a precautionary strategy to ensure that all the red squirrels are getting the correct attention and with the supplementary feeding, I think that this is good to guarantee that the red squirrels are getting sufficient food in order to reproduce and carry on their generation of squirrel. If we look at the data, we can see that there doesn't seem to be any substantial evidence pointing towards community education altering squirrel populations. I'm sure that community education has been going on throughout the experiment yet this still doesn't stop squirrel populations decreasing in 2008 and 2009 so we can conclude that it has no effect on squirrel populations.
Management by Managing Woodland
Red Squirrel Friendly
Conifer Trees &Other Shrubs
Good for red squirrels, even when grey squirrels are present
Small Seeded Deciduous Trees
No problem - good for improving overall habitat without damage to the red squirrel
Red Squirrel Negative
Large Seeded Deciduous Trees
Good for red squirrels but only when GREY SQUIRRELS ARE
Bullace or damson
Western Red Cedar
As we all know, red squirrels live amongst woodland and depend on it to supply their food and provide them with shelter. Conifer woodlands are the most suitable habitat to sustain red squirrel populations as they supply small-seeded conifers which aren't as favoured by grey squirrels as they prefer broadleaved woodland. This therefore, is less likely to attract grey squirrels. As well as being small-seeded woodland, it must also have a variety of ages and species of trees so that there is a variety of food for the red squirrels in case any do not bloom during winter months.
(This table shows the friendly, neutral and negative tree species for red squirrels).
I believe that managing the woodland that the red squirrels live in is very important because without it, they would have no source of food or shelter. As we know, the Nature Reserve has been conducting investigations since 2002, which we can see from the graphs (figure 1.5, 1.6 and 1.7), which is when the first management strategy was implemented. This strategy was managing the woodland so that it was habitable by the red squirrels. From the data in all 3 graphs, we can see that since this conservation plan was put in place, the amounts of red squirrels increased until another factor made their amounts decrease which, in this case, was the grey squirrels. From 2002 to 2007, red squirrel populations were on the rise but the squirrelpox virus took hold. Also, when talking to the Nature Reserve, he happened to mention starting to use the strategy called 'defragmentation' where they connect 2 forests together by planting more and more trees. This is similar to what the Cumbrian and Scottish districts did when merging their forests. This 'defragmentation' of the landscape has resulted in considerable genetic mixing of Scottish and Cumbrian genes in squirrel populations up to 100 kilometres from the site of the new forest. This is an aim that Formby Nature Reserve have and will be put into action soon.
There are many management strategies that have been put in place all over the country for red squirrels but people don't seem to be improving the national population of red squirrels. However, the Formby Nature Reserve seems to be doing an extremely good job at encouraging red squirrel populations to reproduce and increase through the management strategies that they have put in place. In my opinion, the best management which they have implemented out of the four that I have mentioned would be 'Management by reducing grey squirrel populations'. I believe that all the strategies put in place are successful to an extent as previously explained but reducing the red squirrels main competition for food and habitat is the most logical and the most successful which is also reinforced through the data that has been collected.
The future seems very bleak for our native red squirrel, as the grey squirrels are continuing to benefit from English woodlands with the sad consequence of declining red squirrel populations. However, if they carry out the steps that are needed to keep red squirrel populations at a healthy level, it is possible that the future for the red squirrels could look rather promising. I believe that the management of all species is essential in our own survival, so I think that people should aid animals in their day to day lives by giving food, shelter, money, etc in order to help them survive.
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