current research

How do ecosystem engineers influence cross-ecosystem resource subsidies?

Congratulations to our former intern-extraordinaire Beth Smith who’s just published her undergraduate research on how mussels can both outweigh and interact with the effects of terrestrial to aquatic resource subsidies on nearshore lake biogeochemistry.  The work was part of our larger NERC RELATED project.

 

The results are summarised below.  Well done Beth!

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How we can protect biodiversity outside of parks?

Protected areas deliver enormous benefits inside of their boundaries, but what is their contribution to the biodiversity of broader landscapes?  This is a really important question to answer because there are limits to how much land conservation can meaningfully protect.  Moreover, the 196 governments parties that have signed onto the Convention on Biological Diversity are aiming to protect 17% of the world’s land surface by 2020, but what about the other 83%?  Conservation outside of protected areas is critical to ensure that the spaces between parks aren’t devoid of life.

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How do we get species from one side of the fence to the other?

In a new study, we provide among the first empirical evidence that protected areas may disperse biodiversity and ecosystem services into surrounding landscapes. Continue reading

When does saving nature make “cents”?

Fifty football pitches worth of forest were apparently lost every minute between 2000 and 2012 according to a recent paper by Matt Hansen et al.  And there is little reason to expect this to be different today.  This tremendous pace of forest loss is mostly driven by the clearance of land for agriculture, yet comes at a tremendous cost to the other benefits that people obtain from forests, including carbon sequestration, water purification, and biodiversity.

In a new primer for PLoS Biology – think tutorial more than review – we deliver an overview of the global challenge of reconciling forest conservation with land clearance for agriculture.  We explain how the economic valuation of ecosystem services can provide a way to choose between allocating land to either conservation or development, highlighting a new paper in PLoS Biology by Roman Carrasco and colleagues.  In their paper, Carrasco et al. test how different scenarios of global agricultural production might trade off against the multiple ecosystem services delivered by tropical forests.  They find that the value of those services destroyed by deforestation exceeds the economic benefits of agriculture, except in a few regions if greater yields of high-value crops are eventually realised.  Together, the analytical framework and results of Carrasco et al. should inform the spatial prioritisation of real-world interventions such as REDD+ and can help deliver better environmental and economic outcomes worldwide.  Definitely worth a read!

Finding “hidden” effects of nonnative plant invasion

I seem to have missed this post by Angela Brandt about her great new New Phyt paper. You should check it out below and follow her blog to keep up with all the exciting work she is doing:

Angela J Brandt

In my post-doc work on how colonisation and diversification of plant lineages can have a legacy effect on extant plant communities, we previously showed that understanding evolutionary priority effects is necessary to predict the structure and function of pristine ecological communities. In a paper just published in New Phytologist, we tested whether anthropogenically-driven changes in available habitat and mass immigration (i.e. non-native invasion) eliminate the role of evolutionary priority effects in community assembly. We advanced the theory that radiating lineages can monopolize niche space by showing that evolutionary drivers of community assembly also operate in new habitat created by anthropogenic disturbance. However, we also demonstrated that non-native invasion can erase the otherwise strong role of evolutionary priority effects in shaping native community composition. This work is important and timely because it indicates that effects of human-induced global change on community assembly extend beyond purely ecological dynamics to the ecological consequences of…

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Change (your seed size) fast and multiply

Our latest paper examining the role of life history traits in explaining the vast unevenness of species diversity across the flowering plant Tree of Life has just appeared online at PLoS Biology.  The paper was led by Javi Igea and emerged from a very successful BBSRC DTP rotation project by Eleanor Miller, in collaboration with Alex Papadopulos.

Using the largest available phylogenetic tree of plants coupled with an unparalleled trait dataset, we analysed how seed size and its rate of change across the phylogeny were correlated with the rate of species formation.  Seed size is crucial to plant evolution because it confers adaptation to different environment conditions and influences many other aspects of life history, including dispersal, resistance to stress, and colonisation potential.  We subsequently found that faster rates of seed size change were associated with faster rates of speciation, probably by fostering the appearance of reproductive barriers between lineages.  We also found that smaller-seeded species speciated faster than larger-seeded ones.  These results underscore the importance of morphological traits, and particularly their rate of evolution, in promoting species divergence across one of the largest radiations of organisms on the planet.

Although it has taken a bit longer than we would have liked – no thanks to some poor timing with #BAMMgate – the paper brings together an impressive toolbox of complementary macro-evolutionary analyses to deliver a compelling explanation for one of nature’s enduring mysteries.  Well done all!

Forests feed lake life

Our latest paper has just appeared in Science Advances.  In it, we present widespread evidence that aquatic consumers use terrestrial resources depending on the features of surrounding catchments.  It is really nice to see this out as it caps the food web workshop we organised in Cambridge more than two years ago and includes data we collected during our summer 2014 field campaign.  There’s a nice write up of the work put out by our friends at the Cary Institute.

The work emerged out of our forest fuel fish growth story, which hinted that there can be a lot of variation in the extent to which lake food webs use terrestrially derived material, depending on the features of the surrounding catchments.  With funding from a NERC collaborative grant, our new paper managed to assemble the largest dataset to date of the isotopic composition of zooplankton and their associated food webs from across 147 lakes spanning the boreal to subtropics.  Our aim was to address the use of terrestrial resource in lake food webs once and for all.

Algae and land plants differ in their assimilation of heavy versus light forms of atoms such as carbon, allowing the ratios between these two forms to be used as dietary tracers.  Using these isotopic signatures, we discovered that half of all the zooplankton samples we amassed were comprised of at least 42% terrestrially derived material, but this was underpinned by large variation ranging from 11 to 83%.  Using some awfully complex stats, we go on to show that terrestrial support of zooplankton was generally greatest in lakes with long shorelines and surrounded by dense vegetation and rich soils.  This work now explains the large variation in terrestrial resource use by aquatic food webs and delivers a major advance towards resolving the ‘controversy’ around this process.

Making sense of canopies

Béatrice Wedeux and David Coomes published a paper in Biogeosciences analysing how environmental factors and selective logging interact to shape the canopies of tropical forests. Using airborne laser scanning technology across a 750 km2peat swamp forest landscape in Borneo, the study reveals strong shifts in canopy height and gap patterns along environmental gradients linked to changing peat depth. In areas where logging roads were detected on historical satellite imagery, the canopy is lowered and has larger gaps, especially so on deep peat where tree growth is thought to be limited by low nutrient availability and waterlogging. The study identifies a close link between the height and the gap structure of tropical peat swamp forests at the landscape scale and reinforces the vulnerability of this ecosystem to human disturbance. The degradation of tropical peat swamps has been at the heart of climate negotiations in Paris, as emissions from fires in Indonesian peatlands over the last couple of months – exacerbated by a dry El Niño spell – approach the total annual emissions of Brazil (1.62 billion metric tons;www.wri.org).

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Airborne laser scanning allows the detection of openings at different height cross-sections of the canopies of old-growth and selectively logged forests.

Read online: Wedeux, BMM and Coomes DA (2015) Landscape-scale changes in forest canopy structure across a partially logged tropical peat swamp, BIOGEOSCIENCES 12(22):6707–6719, DOI: 10.5194/bg-12-6707-2015.