Author: AJ Tanentzap

About AJ Tanentzap

University Lecturer leading a research group interested in predicting how ecosystems will respond to future changes.

Would elephants really replace the woolly mammoth?

Rewilding involves restoring nature at large scales, typically by reintroducing species that have gone extinct and have had important interactions with other organisms.  It has received a lot of popular attention lately, helped in part by George Mobiot’s 2013 book Feral and its growing number of success stories.  But the idea of rewilding remains highly controversial, particularly when it involves adding apex predators like wolves into places with people.  One the reasons for the controversy is the lack of empirical data to assess the effectiveness of its outcomes.  Conservationists are often relying on a handful of well-known examples, such as from Yellowstone National Park.

rewildcoverIn a new paper published last week in the Philosophical Transactions of the Royal Society B, we now summarise the numerical data around whether rewilding works and identify the biases in experimental study.

The paper is part of a special issue on rewilding, organised by Elisabeth Bakker and Jens-Christian Svenning, to which we were kindly asked to contribute towards.  And we were even interviewed in last week’s issue of Science about the special issue and importance of trophic rewilding for the important task of keeping the Arctic cool.

 

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Digging into lake microbiomes

Two new papers have just been published from our RELATED project.  The work shows how future changes in forest cover around lakes will influence the contributions of inland waters to global carbon cycles.

The first paper published in ISME finds that the positive effects of microbial diversity on CO2 production depends on present and past environmental gradients.  Using a space-for-time substitution for forest greening, the study also finds that a doubling in the tree cover around lakes can increase CO2 production by five-times.  More broadly, the work highlights how widely reported biodiversity-ecosystem functioning relationships need to be contextualised with other ecosystem properties.

A second paper published in Global Change Biology sheds light on the mechanisms underpinning the decomposition of terrestrial organic matter in lake sediments.  Using the RELATED experimental platform, the study finds that identical organic matter additions to sediments have contrasting outcomes for carbon cycling depending on lake-specific characteristics.  In lakes with clear waters, future increases in terrestrial organic matter inputs can stimulate CO2 production because of photo-oxidation.  By contrast, bacteria in darker waters may possess functional genes for degrading organic matter, thereby priming their productivity.  I’m particularly proud of the teamwork on this one, which involved almost the entire group!

Farting lakes warm the world

Lakes release gas too.  In the latest paper freely available from our RELATED project, we show that the vegetation in and around lakes can play an important role in influencing how much of the potent greenhouse gas methane is produced by microbes.  The story, led by our former postdoc Erik Emilson, has been covered by BBC News.

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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!