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The Urban/Wild Divide

Over half of the world’s population now live in cities, and this figure is rapidly increasing. Our progressively more urban world brings the future of wilderness into question. There is a need for a better relationship between urban and wild spaces. Nature and the wild has the potential to become valuable, if not a vital partner in urban environments.

We are a species that construct and delimit ‘wild’ spaces, with our National Parks and wildlife reserves, places where humans are mostly absent. We also built our ‘human’ places like cities, where the wild is assumed to be kept away or non-existent.

Many assume that in an urban environment, with often limited space, there is no room or perhaps need for wilderness. There is this notion that our green spaces must be created, designed and manufactured by humans, with no thought to let nature set its own course.

The famous conversationalist and author, Aldo Leopold, once wrote; ‘No tract of land is too small for the wilderness idea. It can, and perhaps should, flavour the recreational scheme for any woodlot or backyard’.

It is easy to see, however, why people would think that the wild doesn’t belong in urban settings. Urbanisation impacts greatly upon the environment; fragmenting existing habitats, altering the composition of not only the land, but also the hydrology and temperature, whilst creating new pressures such as light, air and noise pollution. All of this results in major impacts to ecosystems and on wildlife.

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Is There Room for Nature Here? (Source; Tony Bock)

 

Despite the challenges to it, nature and the wild endures in urban environments. Nature utilises the available resources, and over time as it adapts and becomes ‘urbanised’, habitats and species have the ability to flourish.

Insects have become very well adapted to urban living. Due to phenomena such as the heat-island effect, there are actually more insects living in cities than in rural areas. These insects are now a vital component in urban ecosystems.

Despite their importance, insects represent a much berated class in society. Most people want rid of them as they associate insects as being pests, from the creepy crawly in the bathroom to the ants in the back-garden.

Many studies have shown the benefits insect species can in urban areas and on many areas of human life. They perform vital tasks such as; helping break down dead plants and animals to controlling pests.  Bees and other pollinating insects are fine examples of underappreciated species, yet they are common in urban areas and play a vital role in human health, food production and agriculture.

Bees, of which there are over 100 different species in Ireland, help in the pollination of food crops, such as tomatoes, apples, and strawberries. The same food crops which we rely upon for sustenance, rely upon pollination to help maximise fruit production and nutritional quality.

A better connection with our urban wildlife can lead to numerous benefits and provide great values to humans. Although many of the benefits are hard to quantify, they include opportunities for recreation, mental and physical health, and scientific values.

Urban wilderness also acts as a multi-generational living resource. A multi-purpose resource for young and old, capable of acting as a playground, potential area for research and study, even purely as a retreat for people from their busy urban lives. It offers all of these functions, and many more, providing numerous co-benefits at little to no cost.

It is clear that there are both positive and negative interactions between people and urban wildlife. There is a need to move the focus away from the idea of a conflict and towards the benefits  that wildlife can offer. For this to occur more value must be placed on urban wildlife. This can be done through better wildlife education.

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Outdoor Classroom (Source; Hagerty Ryan)

 

Better education prevents misconceptions, ill-informed decision making and has the potential to spark a cultural shift to the view of wildlife as an integral component of urban spaces.

There are other ways that are developing in science and engineering that are helping to reconnect people and our cities with nature and dissolve the imagined wall between the wild and urban spaces.

Concepts such as nature-based solutions hold only have the potential to act as a bridge between nature and urban spaces, but also can become a ‘solution’ to many of our climate-related challenges and social issues.

As defined by the European Commission, ‘nature-based solutions to societal challenges are solutions that are inspired and supported by nature’ (EC, 2015b). This management approach offers the opportunity to bring in more diversity, nature and natural features to our urban landscapes.

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Installations such as green belts around cities, and living roofs and walls in buildings, are nature-based solutions that result in not only reconnecting people with nature, they create healthier work/living spaces, reduce the impact of extreme weather events, increase urban biodiversity, offer educational opportunities, the list goes on.

Wild nature is already present in many of our cities, it often just goes unnoticed or is simply just perceived as suspected neglect and is associated with disorder. By establishing acknowledged wild nature in our urban spaces we can create the acceptance and appreciation needed to form nature into an integral part of our urban environments.

Read more on http://connectingnature.eu/blog-articles

Blog by Adam Fowler, Connecting Nature Intern, TCD. Adam is currently studying for an MSc in Global Change: Ecosystem Science and Policy at UCD.    

 

 

Urban bees: Health and pollen foraging of honey and bumble bees in relation to habitat structure

This post is a summary of a pilot project, funded by the Eva Crane Trust, which was set up by Campus Buzz initiator, Fergus Chadwick.

Urban beekeeping is becoming ever more popular, due in part to increased societal awareness of bee decline and people wanting to do something positive for bees. Urban landscapes offer a range of resources for bees, including nesting sites for wild bees, and year-round foraging opportunities for both wild and managed bees. Honey can successfully be produced from urban hives, and demand for locally-produced honey is increasing. In Dublin, Republic of Ireland, urban beekeeping has become common among amateur beekeepers and institutions wanting to improve their “green” image. In addition, wild bees (bumblebees and solitary bees) are relatively common across the city. However, relatively little is known about urban bee health, what they forage on, nor how they are affected by urban habitat structure.

We aimed to investigate bee health and pollen foraging in Dublin, and thus selected nine sites across Dublin (Figure 1) where honeybee hives were already established and maintained by local beekeepers, and into each of these sites, we introduced a small, commercially reared Bombus terrestris audax colony (Figure 2). The sites were selected to represent a gradient of urban landscapes, according to the surrounding habitat, in terms of the amount of urban impermeable surface in the surrounding 500m radius and amount of green space/parkland and residential housing in the surrounding 1500m.

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Figure 1: Locations of the nine bee sites in Dublin

 

Figure 2: Left – Bombus terrestris nest (protected from damage by being placed in a wicker crate, raised from the ground, and protected from rain), Right – Apis mellifera hive on the roof of Trinity College Dublin. (Photos by Fergus Chadwick and Ciara Duffy)

Before installing commercial Bombus colonies in field sites, all were weighed and screened for trypanosome Crithidia and microsporidian Nosema loads. Following installation, colonies were checked once a week and observations of nest activity were made for 60 minutes per colony per week. During this period, workers were captured returning to the nest and pollen sacs removed. One pollen sac per bee was screened for Crithidia and Nosema, and the other analysed for pollen diversity using light microscopy. After five weeks, when colonies had grown to near maturity, but had not produced reproductive individuals, colonies were weighed, brought into the lab, screened for Crithidia and Nosema, and destructively sampled. The difference in initial and final colony weight was recorded as percentage colony growth. Bees were removed from each colony and worker thorax size was measured using digital callipers. Within nests, five cell types were identified: nectar, pollen, larvae, pupae, or nothing and counted.  For each cell type, damage by wax moth larvae, disease or lack of provisioning was noted. The percentage of in-tact “healthy” cells was recorded as an indicator of overall colony health.

During the same period, pollen traps were installed on one honeybee hive per site, and pollen diversity was determined using light microscopy.

We found that there were positive correlations between the percentage urban impermeable surfaces in the surrounding 1500m radius of a site, and the disease loads, worker thorax size, and the proportion of healthy cells in Bombus colonies. There was a negative correlation between percentage urban impermeable surfaces in the surrounding 1500m radius of a site and the proportion of wax moth infested cells. There were positive correlations between the percentage residential housing and disease loads and worker thorax sizes . There were negative correlations between the percentage parkland and disease load and worker thorax size. Pollen analysis has yet to be completed.

Conclusions:

This project has provided the first insight into the health of urban bees in relation to urban habitat structure. The amount of impermeable surface, residential housing and greenspace/parkland in the urban landscape all appear to be associated with the health of commercial Bombus terrestris colonies.

In terms of disease loads, we found that built up areas (with more impermeable surfaces and residential housing) were associated with higher disease loads, and that green space and parkland were associated with lower disease loads. Whether this is due to a difference in colony density, disease prevalence, food availability or other factors, is not yet clear.

In terms of worker size, bees were bigger when there were more built up areas, and smaller when there was more parkland.  This is slightly contrary to expectations – we would expect larger bees where there is more green space, and presumably more floral resources and thus pollen availability. However, many urban parks do not offer much in the way of floral resources, being comprised of amenity grasslands and trees which were no longer in flower during the study period.

In terms of the overall colony health, there were more healthy cells when there was a greater extent of impermeable surfaces in the surrounding 1.5km, but colonies more were infested with wax moths when there was more residential housing. This supports previous studies which have shown high levels of wax moth damage in urban residential areas.

Further analyses are required of pollen collected by bees – these findings will help us to understand what urban bees are foraging on, and potentially to inform urban planting decisions.

This study represents a pilot investigation into the relationships between urban landscapes and bees, using just nine colonies of commercially reared Bombus terrestris, and results should be interpreted with caution and not generalised to all wild bees. However, the results of this study will inform further research in this area.

 

Acknowledgements

This work was led by Fergus Chadwick, supervised by Prof Jane Stout at Trinity College Dublin. We are grateful to Eoin Dillon, Hallie Tanner and Maximilian Fursman, for help with fieldwork and disease screening, to Dearbhlaith Larkin from Maynooth University for disease screening protocol and training, to Dara Kilmartin for pollen analysis, Archie Murchie for help in securing Bombus colonies, and to all the beekeepers who collaborated and allowed us to sample their hives.

A grant from the Eva Crane Trust supported Fergus Chadwick as a part-time research assistant at Trinity College Dublin from February-August 2017. Fergus developed the project, co-ordinated the site selection, field and lab work, analysed the data and initiated Trinity’s “Campus Buzz” (www.campusbuzz.blog).

We would like to sincerely thank Eva Crane Trust for their generosity in supporting our work.

Prof Jane Stout

 

The Irish Pollinator Research Network

The first research symposium of the Irish Pollinator Research Network (IPRN) took place in Trinity College Dublin last week. Members of the research groups of Jane Stout (TCD), Blanaid White (DCU), Jim Carolan (MU), and Dara Stanley (NUIG) met for a one day symposium to share research findings and ideas, and to strengthen and build collaboration between the groups.

 

Screenshot-2018-1-22 Jane Stout on Twitter
Back row L-R: Jim Carolan, Saorla Kavanagh, Blanaid White, Dara Stanley, Sarah Larragy, Sarah Gabel, Jane Stout; Front row: L-R Joe Colgan, Aoife Delaney, Katie Burns, Michelle Larkin, Laura Russo

Launched at the Apimondia / All Ireland Pollinator Plan (AIPP) Biodiversity conference last June, the IPRN is an open network of pollinator researchers committed to building the evidence base for pollinator conservation and management in Ireland. Since the launch of the AIPP in 2015, enthusiasm for pollinator conservation has boomed in all sectors – government, business and civil society. Yet conservation actions need to be effective and need to be informed by a scientific base. The IPRN is providing that base.

At the symposium, research into the effects of agrochemicals and agrienvironment schemes  on pollinator ecology, honey chemistry and bee molecular biology was presented. In addition, work on plant pollination, valuing pollinator services, pollination in West Africa, bee proteomics and genomics, and nature based solutions was described. With two big new projects funded recently (watch this space!), and ongoing collaborative projects, the group is contributing substantially to our knowledge of Irish pollinators and pollination systems.

To find out more, see other blog posts on Campus Buzz and the webpages of the research groups:
Jane Stout
Jim Carolan
Blanaid White
Dara Stanley

 

Ecological adventures in Kenya

Trinity College Dublin runs an annual tropical ecology and conservation field course to Kenya for students in the School of Natural Sciences. This year, I had the privilege of being the botanist on the trip, which gave me the opportunity to teach an excellent group of students, learn from expert instructors, and see a great deal of Kenya.  I felt pretty special because the other instructors on the course were amazing, from the incredible birders John Rochford and Nicola Marples to the amazing physiological ecologist Colleen Farmer all led by the ecological prowess of Ian Donohue. Of course, Collie Ennis, the amazing herpetologist, was also there (he was on the Late Late Show, you know).

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Figure 1 Lunch at Lake Baringo.

The trip is nine days and it is a fast paced trip around four main sites in Kenya: Lake Nakuru National Park, Lake Baringo National Park, Lake Naivasha, and the Maasai Mara. The trip involves several game drives, where the students have a chance to see the famous African “big five”: lion, leopard, elephant, buffalo, and rhinoceros. It provided incredible opportunities to watch ecological processes in action, including five cheetahs devouring a wildebeest.

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Cheetah having Wildebeest for lunch

But there’s so much more than that… this trip gives the students the opportunity to observe the challenges facing conservation in Kenya: small reserves where the population density of herbivores gets so high that buffaloes sometimes kill lions and where, as a result, the lions have learned to sleep in the trees, invasive plant species filling in where overgrazing leaves open spaces, pollution clogging streams, flooding at all of the Rift Valley Lakes, aridification of agricultural regions, and human-wildlife conflicts.

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Figure 2 Lion sleeping in a tree in Lake Nakuru National Park.

I’m personally fascinated by the reptiles, amphibians, mammals, and birds of Kenya, but as the official botanist on the trip it was my job to try and draw the students’ attention to the less mobile (but no less charismatic!!) flora of Kenya. The flora exhibited incredible variation from site to site, but at each site, invasive species (like Prosopis julifera and Opuntia) were in full force.

I was more interested in the native Kenyan flora. I wanted to find a weird Apocynaceae genus Ceropegia (I did not, alas), but I did find Caralluma acutangula in the same family. This plant is so cool because it is a cactus-like succulent in the milkweed family: a perfect example of convergent evolution.

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Caralluma acutangula

In the Old World, the Euphorbiaceae fill the niche that the Cactacecae fill in the New World. They are incredibly diverse and successful, but probably the most striking of the Euphorbia (to me) is Euphorbia candelabrum. It reminds me of the giant Saguaro cacti iconic of the desert southwest in North America.

Figure 3 Euphorbia candelabrum in Kenya (left) and Saguaro cactus in Arizona, US (right) (human for scale).

Of course, in Kenya you really can’t ignore the Acacia (now Vachellia). I mean you really can’t ignore them, since they are covered in painful thorns. One species in particular, the catclaw acacia or “wait a bit” (Vachellia mellifera), uses backward facing thorns to give you time to pause and think about the plant. Note that similarly thorny plants, with similar nicknames, are found around the world, including Australia’s wait-a-while (aka “lawyer cane”, Calamus australis) and the New World’s “wait-a-bit” (Senegalia greggii). Another case of convergent evolution, as both wait-a-bits are Fabaceae but the Australian “wait-a-while” is in the palm family Arecaceae.

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Figure 4 Bat hanging out on a very spiny Vachellia.

It’s hard to be too angry at Vachellia mellifera, since the honeybees make such a delicious honey out of it! Many of us on the course brought home a few bottles of Kenyan acacia honey made from the nectar of the very tree plucking at our clothing and knocking off our hats.

Because I am fascinated by mutualisms, I was most excited to see the famous whistling thorn acacia (Vachellia drepanolobium) being actively defended by one of its mutualistic ant occupants.

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Figure 5 Mutualistic ant defending its plant host from an herbivore.

The plants of Kenya have many mysteries to explore and fascinate the botanical mind. There are well over 10,000 species of flowering plants in Kenya, though a lack of sufficient research means the real number is unknown. I can’t wait to go back and learn more and if you’re interested in this field course (or really any tropical field course), don’t forget to keep an eye on the plants!

Dr Laura Russo is a post-doctoral Research Fellow in School of Natural Sciences, Trinity College Dublin. The fieldcourse is part of the final year programme for Zoology, Botany/Plant Sciences and Environmental Sciences students on the TR060 Biological and Biomedical Sciences degree programme.

Starting with soil…

Dr Laura Russo, post-doctoral Marie Skłodowska-Curie Research Fellow, working on how agrochemicals affect plant-pollinator interactions, describes her first foray into soil analysis…

After discussing my experimental design with collaborators at Teagasc, I realized it was essential to establish the background composition of the soil, to determine whether a) my treatment had an effect on the soil composition over time and/or b) whether the background soil composition at my different sites influenced the health of the plants and their response to my experimental treatments.

For this reason, I took soil samples from each plot at each site in the spring before treatments were applied and then resampled all of the plots at the end of the season after the last treatments of the year were applied.

Thus armed with many kilos of soil samples, I waddled into the soil lab at TCD. I put on a lab coat, latex gloves, and safety glasses, then, under the expert tutelage of Mark Kavanagh (Botany Technical Officer), I conducted some basic analyses on these soil samples:

  • pH
  • Total organic matter in the soil
  • C and N content of the soil
  • P and K content in the soil

The first step to any soil analysis is to air dry the soil samples and sieve them through 2 mm sieves. This removes any large rocks and helps to break up chunks of soil. Don’t underestimate how long this step will take (if you’re doing it by hand)! To process my 32 samples, I spent a few hours a day for about 5 days sieving soil samples.

The next step is to get the soil really dry using a drying oven set to 100C for 24 hours. It’s important to measure how much water (through weight) is lost during this drying step, as you may need that to back calculate future analyses on air dried soil samples, which still have some moisture in them due to humidity in the air.

After those preparatory steps, I took the pH of the sieved and air dried samples. To do this, I measured 1 part soil to 5 parts distilled water and put them on a shake table for 60 minutes. After letting them rest for 10 minutes, I took the pH of each of these samples using a calibrated pH probe.

An important thing to note here is that it’s a good idea to subsample your soil samples to see how much variation there is within a given analysis. Obviously, if there’s more variation between subsamples within a sample than between different samples, that analysis is not revealing any meaningful variation between sites or treatments.

I used the oven-dried samples to then measure the total organic matter in the soil, keeping them in a desiccator while weighing them out to ensure that they didn’t absorb any moisture from the air (which would artificially inflate the organic content by making them heavier). Once the samples are weighed into crucibles, they can be placed in a furnace at 500C for 3 hours.

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Figure 1 Soil samples before being dried in a 500C oven.

The most interesting thing about this step was that before the samples went into the furnace, they varied in colour and texture (Figure 1), suggesting there was a variety of soil compositions. However, after they were cooked in the furnace, burning off all organic matter…

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Figure 2 Soil samples after being dried in a 500C oven.

They all changed to the same colour! This visible change was really striking to me, not only because they looked so different before and after, but because after the furnace all the variation between samples disappeared. That suggests to me that the colour variation was all due to organic matter, which is just cool.

The next analysis I did was on the total carbon and nitrogen content of the soil. To do this, I had to mill all my samples to a fine dust. To do this, I measured out a known weight of air-dried soil into bowls with zirconium oxide balls, and then put them in a ball mill. The mill spins the samples around at 650 rotations per minute for two minutes…in other words, really fast! The bowls have to be very securely fastened in the mill or they can explode out of it. Fortunately, that did not happen with my samples. They were all well-secured and milled into a very fine powder.

This fine powder was then measured into tiny tin cups, which was dropped into a vario TOC cube, which measures nitrogen and carbon content by means of high temperature digestion.

Finally, I measured the amount of P and K in the soil by doing a nitric acid digestion of the oven-dried soil samples. For the nitric acid digestion, I weighed a known volume of dried soil into glass tubes and then added 10mL 69% nitric acid. These tubes were left to cold digest for 24 hours, then they were boiled at 120C for 2hr and 140C for 1hr.

After all the samples cooled, the compounds of interest were in the supernatant, so I filtered the soil out and diluted the samples to 100mL with distilled water. This step was really interesting because of the beautiful colours that appeared.

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Figure 3 Beautiful colours of filtered soil samples in nitric acid.

Not only were these colours aesthetically appealing, they also correlated strongly with site. Two of the sites were orange, one was pale yellow, and one was bright red! These colours are likely related to metals in the soil (for example, iron shows up as red).

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Figure 4 More pretty sample colours.

Stay posted if you want to hear more about the results of my analyses!