Many of the world’s wetlands are highly degraded and they are one of the most threatened types of ecosystems. To attempt to halt or reverse this trend, there are lots of small and large restoration projects underway in many places. One of the most widely-used restoration methods is to re-introduce flooding to degraded wetlands, with the idea that if you provide water, the plants that were there before will return. Unfortunately, we haven’t had much success predicting the outcome of these restoration efforts and we do not always understand why restoration succeeds or fails.
Dawson explains that understanding how different filters affect plant traits means we may be able to predict and manage restoration more…
The BES meeting 2016 in Liverpool is now over and what a great meeting it was. Don’t worry: if you could not make it this year, you can hear all about it in the new blog post below from Jane Catford, our new Associate Editor. Jane kindly accepted to share her thoughts with you on the best moments of the meeting.
Pierre Mariotte Blog Editor, Journal of Ecology
My first time in the home of The Beatles, my first time dodging owls at a poster session, and my first time being serenaded by a rotund frog in a bar. Clearly this was my first BES meeting, and – safe to say – it did not disappoint.
I’ve heard a lot about the BES meetings from colleagues all over the world. Being field season in Australia (my home until five months ago), I’ve never actually made it to one of these meetings before…
Applications are now open for a fully funded PhD position at the University of Southampton, UK starting in the 2017/2018 academic year under the supervision Marc Rius and me.
The project will examine the similarities and differences among species that are invasive and non-invasive across ecosystem types (marine, freshwater, terrestrial) and taxonomic groups (plants, vertebrates, invertebrates) with the aim of identifying a common set of characteristics or life strategies shared by all invasive species. Exact details will be worked out with the successful applicant.
Information about the project and how to apply can be found here. Applications will close on 2 January 2017.
Chris Walsh, Joe Greet and I are looking for a PhD student to join us at The University of Melbourne on an ARC Linkage Project that aims to quantify the importance of flooding, seed availability, and competition for restoring a degraded wetland forest. Think field surveys, experiments, theory and the opportunity to work with Melbourne Water, Parks Victoria, Zoos Victoria and Greening Australia.
If this sounds like fun, read on to see the full advertisement.
In July, I will be shifting my office some 17,107 km to the University of Southampton. I’ll be starting a lectureship (equivalent of Assistant Professor) in Community Ecology in the Centre for Biological Sciences where I’ll be part of the Environmental Biosciences research group.
A member of the UK’s Russell Group, Southampton is one of the leading teaching and research universities in the UK and is currently ranked 81st in the World by the QS World Rankings 2015. Students come from across the UK and from over 135 other countries, making it an exciting place for researchers, teachers and students.
It is also in a great – and the sunniest! – part of the UK. An hour and twenty minutes from central London, it is on the south coast, nestled between New Forest and South Downs National Parks, which are less than 20 km away. Southampton has a local airport with flights throughout Europe and Heathrow is less than an hour away, making national and international travel easy.
I’m incredibly excited about establishing a lab and research program in Southampton. I’ll be actively trying to grow my lab, so please get in touch if you’re interested in working with me as a student, postdoc or collaborator. I’ve got ideas for potential projects but would love to hear others. You can reach me on: catfordj[at]unimelb.edu.au.
For those interested in postgraduate research, here are some starting points for information on courses, scholarships and life in Southampton:
To meet increasing demands for livestock production, agribusinesses around the world are breeding new varieties of pasture plants. Unfortunately, many of the plant characteristics promoted for use in pasture – higher growth rates, greater resistance to disease, higher tolerance of environmental extremes and higher reproduction – are shared by invasive species. Coupled with the fact that many pasture species are already highly invasive, this effectively means that agribusiness may be inadvertently breeding “super weeds”, which farmers then spread across the landscape.
And, just to make matters worse, this increased weed threat is going largely unchecked: even countries with leading biosecurity do not consider the weed risk posed by plant varieties that are developed within-country.
But all is not lost!
As described in a new PNAS paper led by Don Driscoll, there are various ways in which this problem can be fixed.
Ever wondered why there are so many plant species – and so much weed invasion – along rivers?
At first glance, one might attribute this to the lush conditions of riparian ecosystems: lots of nutrients + loads of water = ideal conditions for plants. This coupled with the fact that riparian systems are on the interface of aquatic and terrestrial ecosystems, so are home to a rich mix of wet- and dry-loving species? Makes sense.
However, when you really think about the conditions of riparian ecosystems – physical disturbance from floods, inundation and desiccation, ice scour in cold places – then they perhaps don’t seem quite so hospitable. Like rocky intertidal platforms, presumably the species that live in riparian zones need to have some pretty specialised adaptations to be able to cope.
In a recently published Tansley Review in New Phytologist, Roland Jansson and I focus on the key structuring forces of riparian zones, plant ecophysiological traits and mechanisms of species coexistence to resolve the apparent conundrum between the high floristic diversity of riparian ecosystems and their challenging environmental conditions.
We describe 35 traits that enable plants to cope with riparian conditions. These include traits for tolerating or avoiding anoxia and enabling underwater photosynthesis, traits that confer resistance and resilience to hydraulic disturbance, and attributes that facilitate dispersal, such as floating propagules. This diversity of life-history strategies illustrates that there are many ways of sustaining life in riparian zones, which helps to explain high riparian biodiversity.
Using community assembly theory, we examine how adaptations to inundation, disturbance and dispersal shape plant community composition along key environmental gradients, and how human actions have modified communities. Dispersal-related processes seem to explain many patterns, highlighting the influence of regional processes on local species assemblages.
Treating alien plant invasions like an (uncontrolled) experiment in community assembly, we use an Australian and a global dataset to examine possible causes of high degrees of riparian invasion. We found that high proportions of alien species in the regional species pools have invaded riparian zones, despite not being riparian specialists, and that riparian invaders disperse in more ways, including by water and humans, than species invading other ecosystems.
You can find the paper details here and a free pdf copy here.
Please get in touch if you have any comments or questions – I’d love to hear them.
Ecologists, like epidemiologists, are often confronted with the challenge of trying to determine causality by piecing together bits of information observed in nature. When the presence or absence of a species at a site is affected by the characteristics of the environment and community, the availability and dispersal success of propagules, stochastic events and the peculiarities of the species itself, it can be very difficult to isolate the likely mechanisms that lead to the occurrence – or lack thereof – of a particular species, especially when the influential factors are highly correlated.
Experiments are obviously made for getting around such problems; by controlling and isolating one factor at a time, the relative importance of different factors can be quantified. However, experiments are not always possible, desirable or ethical. Take plant invasions along rivers, for example: they occur at large spatial and temporal scales; many factors may drive the invasion process; introducing and augmenting the supply of invasive species is unpalatable and likely prohibited; plus, river environments are very hard to control and manipulate, as any manager will tell you. So, if we are limited to potentially confounded survey data, how can we more effectively identify the drivers of plant invasion so that we know which factors to target in weed management?
In a paper recently published in Diversity and Distributions, my colleagues and I contend that incorporating data about species characteristics into survey-based approaches provides an additional line of evidence that can be used to improve inferences drawn from patterns. We illustrate how using information about environmental gradients, species distributions and species characteristics can increase understanding of ecological phenomena – here, riparian plant invasion, which can help inform management responses.
Using this approach, we find that, of four hypotheses examined, hydrological modification (indicated by flood magnitude) most likely drives invasion in River Murray wetlands. Flow regulation may inhibit native species adapted to the historical hydrological regime, facilitating exotic species with different environmental ranges. A symptom of environmental change, invasion may have been exacerbated by drought, although it is unclear why.
There was no indication that human-increased propagule pressure or colonisation ability facilitated invasion. Exotic cover was unrelated to proximity to towns, recent flood frequency and cattle grazing intensity. Additionally, similar proportions of exotic and native species were used in cultivation and, despite a higher proportion of exotics being known weeds, weed status was unrelated to exotic species occupancy. Overall, colonisation ability was unrelated to species’ origin or response to water depth and hydrological change. Although exotics had higher specific leaf area and shorter longevity (indicative of higher colonisation ability), they had heavier (not lighter) seeds and did not differ in height from natives.
Based on our findings, we conclude that (i) using environmental flows to reinstate mid-range floods and (ii) augmenting the propagule supply of native species with characteristics suitable for modified conditions may help limit invasion in these wetlands.
For more, have a look here or drop me a line and I’ll send you a copy. I’d be delighted to hear any thoughts, comments or queries that you may have.
While perusing my emails recently, I had a delightful surprise: an email notifying me that I have been awarded the 2015 Australian Society for Limnology Early Career Excellence Award.
The award is given to limnologists based on the contributions they have made in the first ten years of their professional life. I am thrilled, humbled and very honoured to receive such an acknowledgment from my freshwater colleagues.