We recently held our departmental lunchtime “Conservation Conversation”, discussing whether or not invasive non-native species (INNS) are really that bad after all. This is an interesting concept to think about, especially for Zarah Pattison and myself who both work on different groups of invasive species in Stirling University’s Natural Sciences department. This is particularly in light of the flurry of books, namely Fred Pearce’s “The New Wild” and Ken Thompson’s “Where do camels belong?” which are promoting INNS. There has been a storm of surrounding media attention and outrage from invasion biologists worldwide. But who is right? And if they are “Nature’s Salvation” (Pearce, 2015), then are we wasting money on biological control of these organisms?

This debate was at the heart of our discussion, opening the floor to discuss what kinds of INNS were most prevalent in people’s minds and how they receive their information on INNS. This was a slightly biased sample as everyone in the room has studied or worked in an environmental academic department. We found that not one of the 15-20 people mentioned a vertebrate (which in my opinion is pretty awesome due the ‘fluffy-crew’ normally being particular popular!). There was a consensus with regards to the negative role INNS play in invaded ecosystems, except for one outlier who suggested the malicious role of these invaders to be species specific.

Fairly indiscriminate diners, coquies will eat almost anything that enters their range (R. Cauldwell)

Zarah: I always campaigned against INNS from undergrad. Digging deeper into the role these species play in native ecosystems is fascinating. I have definitely crossed over into the “intermediate” playing field of thinking that the impacts of INNS are both species and context specific. In a biodiversity hotspot such as the Western Cape, South Africa, Acacias (for example Acacia mearnsii) have a direct impact on water resources. Hawai’i, so well-studied for island invasions, is teaming with INNS. From Fountain Grass (Pennisetum setaceum) which dominates the landscape outcompeting native plant species, to the Coqui frog (Eleutherodactylus coqui) which has no natural predators and feats on native insects. However, we still receive mixed messages regarding impacts on native diversity, particularly for some of our most expensive invaders in the UK (in terms of clearing and management), such as Himalayan balsam (Impatiens glandulifera). Clarification is definitely needed. Are these species having a direct impact on native biodiversity, particular in degraded urban habitats, or are they merely passengers of some other human-mediated disturbance?

The harlequin ladybird is notorious invasive species that was originally released for biological control (Mike Majerus)

Katie: Before starting work on my PhD, I had worked on harlequin ladybirds (Harmonia axyridis) for my Masters project. I therefore also think of biocontrol going hand-in-hand with INNS, and knowing that the harlequin had been initially released as a biocontrol agent, I had negative opinions towards when starting my PhD. As much as I applaud a reduction in the use of pesticides in agriculture, I was strongly of the opinion ‘this is what happens if you release a species into a novel area – it will take over and cause species declines’. However I take this all back! The harlequin is a particularly good example of biocontrol ‘gone wrong’. There are many examples of successes, preventing the use of pesticides that at times won’t even work due to the resilience of pest species. An example of research in this area currently being conducted in Ireland is the Eucalyptus beetle (Paropsistern selmani) which was accidentally introduced from New Zealand. These beetles defoliate Eucalyptus trees used in the floristry industry, and therefore causes an economic problem for growers. The parasitic wasp (Enoggera nassaui) has been proposed as a suitable biological control agent to bring the invasive beetle population under control. The use of pesticides in this system previously resulted in a native pest species left uncontrolled by native parasitoids (the pest species being resistant to the pesticides) and creating a further problem in the industry. Thorough research is necessary to ensure that the target beetle is the only species affected otherwise there could be risks to native beetles species.

Tunnel of Japanese Knotweed (Fallopia japonica) partly cut back on the Black Cart Water, Scotland. (Z. Pattison)

One of the most interesting things to come out of this discussion was that with every INNS debate that day, you could have argued both for and against the invader. In many ways the positive press has just highlighted the fact that we need more data and studies on the effects of INNS in invaded ecosystems, if not only to disprove the notion that these species have no impact. We cannot make science based policy, management etc. decisions without all the information. They say that all publicity is good publicity, well us invasion biologists are ready and willing to go all the way, fighting.

First posted in Stirling Conservation Science on 22 December 2015.

I was outraged by a BBC news presenter who quite candidly announced on National television, “Can we really live alongside these animals?”

Beaver on the River Otter in Devon © Dave Land

The presenter was referring to the Devonshire beavers who have taken up residence along the River Otter. These beavers had arrived unannounced and seemingly flourished in their new home. It is not certain how long they have been occupying the area, between 3-5 years has been estimated. What if it was longer? The fate of humans has not been doomed during that time. I have not seen any evidence of the struggle between human and beaver played out, such as that of a threat to our societal rights.

I am ranting of course. Though the message I heard was quite clear. For all the efforts that Scientists, policy makers and those in the realm of nature conservation make, it seems a crying shame that we have people questioning these achievements and impeding progress. Are we only willing to accept nature if it does not stand in our way?

Ken Thompson, in his book ‘Where do camels belong?’ raised a similar issue. We intentionally introduce certain animals and plants from all over the world, reaping their beneficial properties. However, once they become unmanageable, we want to remove and destroy them.

“Generally speaking we like animals and plants that are attractive and don’t cause any trouble…” (Thompson, 2014).

Animals and plants must boxed and controlled in a corner, where they can serve their duty to humanity.The successful rabbit (Photo: Alamy) and rare brown hare (Photograph: Fischer/Getty Images). Which one do we prefer?

 Understandably, livelihoods play an integral part in such emotive subjects such as introductions and reintroductions. An example which had a profound impact on me personally was the BBC documentary ‘Land of the lost wolves’. Researchers gaged the opinion of ranchers in Washington’s Cascade Mountains on the return of the Gray wolf and some are deeply unsettling. Similarly, the reintroduction of Gray wolves to Yellowstone National Park is a key example of conflicts between humans and wildlife. This ecosystem engineer was reintroduced in 1995 and successfully increased their range and population size.  Alpha female, 832F (A.K.A 06 Female) of the Lamar Canyon Pack, amongst other wolves, was shot by licenced hunters. This waged an international outrage.

Natural England approved a five year monitoring trial by Devon Wildlife Trust on the 28^thJanuary 2015. The beavers can stay, for now. As long as they remain disease free of course. What can we, as scientists, educators, policy makers etc, do to collaborate more effectively with people?

This topic is vast and this post is just an opinion (perhaps just another superficial outburst), but one which leads to a final burning question. Isn’t it about time we learnt how to share?

“In the end we will conserve only what we love. We will love only what we understand. We will understand only what we are taught.” Baba Dioum, 1968.

Photo of Earth taken by the crew of Apollo 8 as they orbited the moon in 1968. (Nasa/Time & Life Pictures Nasa/Getty)

For more information on a previous beaver monitoring trial see:

Willby, N., Perfect, C. and Law, A. 2014. The Scottish Beaver Trial: Monitoring of aquatic vegetation and associated features of the Knapdale lochs 2008-2013, final report. Scottish Natural Heritage Commissioned Report No. 688.

Thompson, K (2014) Where do camels belong? London, Profile books LTD.

First posted in Stirling Conservation Science on 30 January 2015

Invasive alien species (IAS) have been the focus of many a debate recently (http://www.bbc.co.uk/news/science-environment-21509016), with research in this area flourishing. Indeed for job creation purposes (make space for me in approximately 2.5 years!) the attention invasive alien plant species (IAPs) in particular are now receiving, is very welcome. However, shifting attention sparks off debates, one in particular being our  knee-jerk and almost xenophobic reaction towards anything alien within ‘natural’ ecosystems (which, let’s face it have not been very natural for hundreds if not thousands of years).

© 2009 UK Weed Control Ltd

IAS are widely stated to pose the second largest threat to biodiversity after habitat destruction, through out-competing native species, affecting agriculture and forestry, as well as posing human health risks (Richardson and van Wilgen, 2004). Although the threat of biological invasions is well established within the scientific literature, there is still a sizable gap in our knowledge on the true extent of impact by some well-known invasive species. This is of significant concern given the resources invested in control of IAS (Approximately £1.7 billion) given the limited resources currently made available for conservation of biodiversity. In some cases, the negative effects of IAS on ecosystems are merely assumed and often disputed. In the case of IAPs it seems there is little agreement over how much is too much and therefore how much is damaging to ecosystems. (see e.g. Hulme & Bremner, 2006 and Hedja & Pyšek, 2006). More research is needed.

Nothing lives under this Japanese knotweed patch along the Black Cart Water, other than (temporarily) myself and field assistant, David and perhaps some ground elder around the periphery of the patch.

From my own experience locating field sites for my research three Invasive Plant Titans dominate alongside rivers in semi-urban areas: Giant Hogweed (Heracleum mantegazzianum), Japanese knotweed (Fallopia japonica) and Himalayan balsam (Impatiens glandulifera). Indeed, one might well ask if a swathe of rather attractive, orchid-like flowers, (aka Himalayan balsam), isn’t preferable aesthetically to dense brambles and stinging nettles (neither of which is much fun to walk through…) in the built up White Cart Water in Renfrewshire?

Himalayan balsam invaded public walkway along the otherwise nettle and bramble infested White Cart Water in Renfrewshire.

So should we be more accepting of these ‘displaced weeds’? After all, a weed is just a plant in the wrong place at the right time, exploiting its new found environmental wealth. The same could be said for humans. A recent editorial in Nature by Chris Thomas (Thomas, 2013) has left me both intrigued and slightly frustrated. He raises the possibility that, at a time when species are declining at one of the fastest rates in the history of our planet, IAS will actually increase biodiversity through their potential to hybridise and potentially naturalise. This in turn raises the question of whether there is merit inconserving IAS?

© 2012 Garden Route Initiative, Working for Water Programme.

Globally IAS are a recognisable issue and in some countries the consequences of a tolerable approach to invasion would be truly detrimental to the well-being of local people. For example, in countries like South Africa, IAPs pose a direct threat to water security. In this respect the public have been made aware of IAPs and their threats and programmes, such as ‘Working for Water’, have engaged with communities for almost two decades in the fight against invaders. Thomas (2013) discusses our intolerance to IAS and emphasises that money should be targeted at the battles we can actually win – a point it is hard to argue with. However, climate change and human-mediated global dispersal are together moving the goal posts and changing the combatants in invasion wars and we just cannot predict the winners and losers.

First posted in the Stirling Conservation Science blog: 28 October 2013

References

Hejda, M. and Pyšek, P. (2006) What is the impact of Impatiens glandulifera on species diversity of invaded riparian vegetation? Biological Conservation, 132, 143-152.

Hulme, P.E. and Bremner, E.T. (2006) Assessing the impact of Impatiens glandulifera on riparian habitats: partitioning diversity components following species removal. Journal of Applied Ecology, 43, 43-50.

Richardson, D.M. and van Wilgen, B.W. (2004) Invasive alien plants in South Africa: how well do we understand the ecological impacts? South African Journal of Science, 100, 45-52.

Thomas, C.D. (2013) The Anthropocene could raise biological diversity. Nature, 502, 7.

Wading through the River Gryfe with a Himalayan balsam plant in tow.

I had always thought of myself as a resourceful person. Give me a problem, I’ll ‘make a plan’ (a very South African turn of phrase).  However, having just passed my driving test and moved to Scotland, with no experience of working along rivers, or knowledge of what I was looking for, I just panicked. Now, I did have a few crucial criteria to aim for, some being:  make sure I can walk at least 500 metres along the most downstream end of a river, which must be invaded by the invasive plant Himalayan balsam (Impatiens glandulifera). This plant is tall, with bright pink, pungent flowers and I soon became a dab hand at spotting it whilst driving anywhere near a river and, on parking the car, smelling it. After a month of google maps, google earth, broken GPSs and sat navs, I finally found the 20 rivers with 20 suitable survey sights.

All the sites were predominantly urban or alongside farm land, which came with its own suite of issues. However, when getting permission to work along my chosen river sites throughout Scotland, people were generally helpful (unless they were a farmer who thought you were testing the water quality…) and interested in the project. On one occasion we were even brought tea and cake by a landowner, who thought us standing in the rain for 10 hours was horrific (I loved it). The vegetation could reach up to 4 metres high, with stinging nettles up to 3 metres. We got used to the constant burning on our skin and kept ourselves sane by shaking the Himalayan balsam to see which of us would get an exploding seed pod in the eye.

Tea and cake provided by kind cottage Lady on the River Tweed.

When crossing the Annick Water to access a survey site, David, my field assistant, was using a 1 metre wading pole to bash back the nettles so we could climb up the bank. He stood still for a moment and then started shouting whilst trying to cross back to the other side of the river, as we were both repeatedly stung by the angry wasps whose nest he had disturbed. I wanted to dive into the water, but all I could think of was my phone in my pocket, with all the fieldwork pictures on it and all the unsightly floating objects in the river. We finally clambered up the other river bank, running back and forth until the wasps gave up.

Me: “David, where is the equipment bag?”

We looked at each other and then over to the other side of the river where the bag sat, covered in wasps. After an hour, we suited up with every bit of clothing and plastic in our possession, as well as some burning reeds, and finally retrieved the field bag. Many beers were drunk that night.

Geared up and ready to retrieve our field work equipment bag from under the angry wasps nest.

I had to revisit these sites 3 times over the next year and got to know them quite well. In early spring I had to collect the 360 30 x 30cm green AstroTurf mats which had been placed at each site the year before. After winter floods, my red spray painted wooden stakes had mostly vanished and most of the mats were covered in mounds of sediment deposition. I had tried to use a visual marker, like a telephone pole, for each transect where they were placed, measuring the distance between each mat. Sally, my field assistant, and I had a ‘mat dance’: every time we found a mat we proceeded to wave our hands in air and gyrate to the ‘Venga boys are coming’ tune…much to the dismay of many dog walkers.

Finding the AstroTurf mats, covered by mounds of sediment deposition, on the Dean Water.

On the River Almond we had to access the survey site by going down one path on a steep embankment. The river was flowing fast, but I was confident that if we worked quickly we could get the work done. We were about 50 metres from the path, measuring the distance to each mat. I asked Sally to head back to get some more bags for the soil cores and as she turned around, she let out her high pitched alarm call (scream).  The river had engulfed the bank. The bagged soil cores were starting to float down the river, along with the rucksack, which had our car keys in it. I managed to wade out (stupidly) and get the soil core bags and the rucksack (I was not losing any samples!), and we got up the bank safely. Sad to say we lost those mats, but we successfully retrieved 278 across all sites.

Trying to climb through trees and 4 m high Himalayan balsam on the River Endrick, whilst David fights through brambles and Rose Bay Willow herb on the Black Cart Water.

Attacked by wasps, intimidated by aggressive dogs on sites located in run down areas, accused of bombing the river as a poacher, constantly being mistaken for fishermen, stung by stinging nettles, even offered to a farmer’s 21 year old son as a birthday present… I wouldn’t change a thing. Most of the time you are alone, it is peaceful and beautiful, and you get used to the sickly sweet smell of Himalayan balsam. The bad experiences make the best stories. And there is nothing quite like being in the field.

Thanks to Alan Law for revealing his fieldwork methods in ‘A short history on the luck, failings and success of field work’, as well as the blog ‘Dispatches in the field’ which has great real life fieldwork anecdotes for all to enjoy and sympathise with!

First posted in Dispatches in the Field on 19th September 2014.