INVASIVE SPECIES AND THE CARP-OCALYPSE

Non-native species are a problem in the environment when they establish new populations and disperse – i.e. become invasive. A highly invasive, global invader of freshwaters is the common carp, a fish capable of reaching weights of over 30 kg as well as producing a large number of offspring, and is proving to be an ecological and economic pest wherever it goes. They are a highly popular species for catch-and-release recreational angling (see Figure 1), as well as being an important species in aquaculture – but this has resulted in their invasion of all continents except Antarctica. They have been invading British freshwaters since at least the Middle Ages and perhaps as early as the Roman Times.

Invasive carp are well known as ecological engineering species, altering the physical habitats of their invaded freshwaters through their aggressive benthic foraging. However, what is less known is the extent of their competitive interactions with native fish species, especially those that have populations which are already threatened with issues such as habitat loss – like the crucian carp, a relatively diminutive fish in the same family as common carp and with similar benthic feeding habits and functional morphology.

Although generating understandings of the interactions of invasive and alien species can be achieved through field studies alone, a major issue with many field studies on invasive species is that they tend to have high context-dependency. For example, while studies provide interesting and useful information, that information is often only insightful to the study site in question due to, for example, issues such as a lack of data prior to the invasion, limited knowledge on the introduction event, the use of one-off sampling events, and a lack of control in the environmental conditions. In combination, this makes it very difficult to draw strong conclusions beyond the study site and species in question. To overcome these issues, in our study we completed two sets of experiments that would help us understand the competitive interactions of the invasive species (common carp) versus the threatened native species (crucian carp) under relatively controlled conditions to understand the processes that might be producing the patterns in our field data. 

The first of these experiments was a set of comparative functional response experiments completed in tank aquaria. As both species shoal, we used the fish in conspecific pairs and at a water temperature that the fish typically experience in Southern Britain during summer (17 oC). We exposed the pairs of fish to a range of prey densities for fixed time intervals to determine their feeding rates. The results showed common carp had much higher feeding rates than crucian carp, suggesting they would monopolise food resources when they are together.

Figure 2. The crucian carp – this small species tends to inhabit ponds which are increasingly invaded by common carp, with our results suggesting the increased inter-specific competition will result in them having to consume a wider range of prey items to survive. ( J. Robert Britton).

This experiment complemented a much larger and longer experiment completed between 2016 and 2019 in a set of three ponds that were drained prior to the experiment (so they started with no fish) and were then seeded with 100 fish of similar sizes into each pond – one with only crucian carp, one with only common carp and one with 50 of each. Although we could not replicate these treatments, we could follow the feeding interactions of the fish across the experiment through the ecological application of stable isotope analysis. We revealed that when only one species was present in a pond, the extent of the food resources each species consumed – their trophic niches – were similar. When they were together, however, the trophic niches of both species were much larger and were very different from each other (they had ‘divergent niches’). These results indicated that their interactions resulted in them having to feed on a much greater range of prey items than when they were separate, with common carp also having to alter their diet – despite being the superior competitor.

These experimental findings were then used to help us interpret the patterns in our field data from four wild ponds where the two species were present together. In all ponds, their trophic niches were also strongly diverged from each other, as per the experimental ponds, and where the comparative functional response data suggested this was driven by the strong competition pressure from common carp.

The use of the two experiments enabled us to identify that the highly invasive species – common carp – is a strong competitor and one that the threatened native species – crucian carp – finds it difficult to compete with. As common carp become more prevalent across the world’s freshwaters, the outcome for fish species already under threat, such as crucian carp, do not look favourable.

This blog post is provided by Victoria Dominguez Almela, Josie South & Robert Britton and tells the #StoryBehindThePaper for the paper ‘Predicting the competitive interactions and trophic niche consequences of a globally invasive fish with threatened native species‘, which was recently published in the Journal of Animal Ecology.

Jane Goodall Roots and Shoots programme and SAMARCH

Last week, Genoveva Esteban and Katie Thompson from SAMARCH hosted two workshops for school children, showcasing SAMARCH research. This was their first workshop as part of Bournemouth University and the Jane Goodall Institute Roots and Shoots programme. Their virtual workshop incorporated a talk on facts about Atlantic salmon, recent research, and interactive elements for the children to get involved in. Their presentation also doubled up as an activity workbook for children to work on from home.

For any questions about the event, or if you are interested in this activity for your school, please contact Katie via email: thompsonk@bournemouth.ac.uk

Restoring Kenya’s most threatened forests

Lindsay Biermann (LEAF)

Across the world, natural ecosystems are becoming increasingly degraded and fragmented. As a consequence, preservation of remaining intact habitats is likely to be insufficient for many species. Instead, the United Nations has identified restoring wild places as a global priority in its upcoming decade on ecosystem restoration.

In response to this, former Bournemouth Life and Environmental Sciences alumnus, Lindsay Biermann, has helped found the Little Environmental Action Foundation (LEAF for short) alongside thirteen fellow young conservationists. LEAF’s mission is to restore some of the most threatened ecosystems across the tropics, whilst using research-driven approaches and 100% native species.

LEAF’s first project is focused on cultivating and planting indigenous trees in coastal Kenya. Situated in the East African Coastal Forest Biodiversity hotspot, this project aims to save the region’s endemic trees that are all predicted to go extinct by 2050 without intervening action. LEAF is working in partnership with Pwani University to recover seeds, grow seedlings and plant out these threatened endemic species around fragments of ancient forest sites called relics. These relics are incredibly important to the future of this region, as currently 96% of native trees have been lost to monoculture plantations and farming.

Using research and expertise, LEAF has begun by employing local graduates and implementing ex situ conservation on the university grounds. From here, we plan to expand our efforts to plant trees close to pre-existing relict sites, educate local people on how to protect these forests and show why their ecosystem services are invaluable. By focusing on native tree species, we aim to increase the survival rates of planted trees and also the long-term recovery of these forests. Collaborative research with university students is also helping to maximise survival rates by studying salt and drought tolerance, as well as optimal planting times.

LEAF is set to officially launch in National Tree week running from 28th November to 6th December. As part of the launch, LEAF is aiming to raise funds to build a new seedling nursery that can propagate and grow rare and endangered tree species. From these donations, LEAF hope to transform the nursery to provide sufficient capacity for future forest restoration projects.

The LEAF charity is remains in its infancy but has ambitious plans to expand its restoration work into ten countries by 2030. Potential projects in Rwanda and India have already been identified, whilst a UK-based school outreach programme is being developed. If you would like to learn more about LEAF’s work, visit their website – www.theleafcharity.com – or follow them on social media @wearetheleaf.

First trees planted in Pwani University

Atlantic Salmon Activity Sheet Answers

Here are the answers for the our ‘World Ocean Day 2020’ colouring sheet:

The figure has been adapted from:

Kryvi, H., Rusten, I., Fjelldal, P.G., Nordvik, K., Totland, G.K., Karlsen, T., Wiig, H. and Long Jr, J.H., 2017. The notochord in Atlantic salmon (Salmo salar L.) undergoes profound morphological and mechanical changes during development. Journal of anatomy, 231(5), pp.639-654.

World Ocean Day 2020

Happy #WorldOceanDay, a day to celebrate our wonderful oceans and all the biodiversity that calls the ocean their home. Our oceans are so diverse, but we would like to focus on a fascinating species today:The Atlantic Salmon! Have a go at our poster, where you can learn the life cycle of the salmon and colour them in! Please share any completed activity sheets with us (drop us a message!) We love to hear from you 🙂

Fab Five: Week 4 Answers

Week Commencing 13/04/2020

Species 1: Manatee

1.What do I eat?

I am a herbivore and most of my diet is made up of different types of grass

2. Where do I live?

There are 3 different species of manatee, which is distinguished by where I live. The West Indian manatee ranges along the North American east coast from Florida to Brazil. The Amazonian manatee species inhabit the Amazon River and the African manatee swims along the west coast and rivers of Africa.

3. How large do I get?

I can grow up to 8-13 ft!

Species 2: Leopard

1.Am I diurnal or nocturnal?

I am mainly nocturnal

2. Where do I live?

I can be found in Africa and Asia, from the Middle Eastern nations to Russia, Korea, China, India and Malaysia

3. Do I like spending time on my own or in group?

I like spending time on my own as I am a solitary animal

Species 3: Hummingbird Hawkmoth

1.How big is my wingspan?

My wingspan is around two inches

2. Where do I live?

I spend the winter in Southern Europe and the summer in the U.K.

3. What do I like to eat?

I feed on the nectar of honeysuckle, red valerian and other flowers

Species 4: Dodo

1.What did I eat?

My diet included seeds, nuts, bulbs, roots and fallen fruit. I would also feed on palm fruit, shell fish and crabs

2. What Island did I live on?

I only lived on the island of Mauritius

3. When did I go extinct?

I went extinct in 1681

Species 5: Deer

1.What do I eat?

I am herbivorous, I only eat plants! This includes plants such as grass, bark, twigs, berries and young shoots

2. What do I use my antlers for?

I use my antlers for fighting with other males

3. How big can I grow up to?

I can grow up to 2 metres in length

Fab Five: Week 3 Answers

Week Commencing 06/04/2020

Species 1: Atlantic salmon

1.What do I eat?

I eat insects, invertebrates and plankton when I am young

2. What do you think I find on my journey to the sea and back?

I swim out to the Atlantic into rich feeding grounds. I primarily feed on fish such as capelin, herring and sand eel.

3. How large do I get?

I can grow up to 28-30 inches after two years at sea.

Species 2: African elephant

1.How big do I grow up to?

I can grow up to 8-13 feet from shoulder to toe!

2. Why do I need to cover myself in mud and dust (apart from it being fun!)?  

I cover myself in mud as it acts as a natural sun cream and stops me from getting burnt

3. What is the name of a female elephant that leads a group of elephants?

She is called a Matriarch

Species 3: Tardigrade

1.How big am I?

I range from 0.3 to 0.55 mm in length, although the largest species may reach 1.2mm

2. Where do I live?

I can be found in almost everywhere on earth. I am often found on lichens and mosses because that’s where I like the most

3. What do I like to eat?

I feed on plant and animal cells. Some of us are known to eat entire live organisms (microbes of course) such as rotifers.

Species 4: Velociraptor

1.What did I eat?

I was a carnivore that hunted and scavenged for food. I spent a lot of time eating small things which included reptiles, amphibians, insects, small dinosaurs and mammals

2. When did I live on the earth?

Fossils of me have been found in the Gobi Desert

3. Where was my first fossil found?

My first fossil was found in Mongolia in 1924!

Species 5: Indian Hornbill

1.What do I eat?

I love to eat fruit! My diet mainly consists of fruit, insects and small mammals  

2. Which countries do I live in?

I can be found in the forest of India, Bhutan, Mainland Southeast Asia, Sumatra and North eastern region of India!

3. How big can I grow?

I grow up to 95-120cm!