Uncommon Ground

Author Archive: kent

The debate about new conservation and alternatives

I mentioned a couple of weeks ago that I fall roughly into the camp of New Conservationists. When I took the Future of Conservation survey, I scored relatively strongly on  “means of improving human welfare” and slightly positive on “willingness to embrace markets and capitalism.” In catching up on my reading this weekend, I discovered that the folks behind the survey also surveyed attendees at the 2015 International Congress of Conservation Biology. Here’s the abstract of the paper describing what they found (full citation and link below):

A vibrant debate about the future direction of biodiversity conservation centers on the merits of the so-called new conservation. Proponents of the new conservation advocate a series of positions on key conservation ideas, such as the importance of human-dominated landscapes and conservation’s engagement with capitalism. These have been fiercely contested in a debate dominated by a few high-profile individuals, and so far there has been no empirical exploration of existing perspectives on these issues among a wider community of conservationists. We used Q methodology to examine empirically perspectives on the new conservation held by attendees at the 2015 International Congress for Conservation Biology (ICCB). Although we identified a consensus on several key issues, 3 distinct positions emerged: in favor of conservation to benefit people but opposed to links with capitalism and corporations, in favor of biocentric approaches but with less emphasis on wilderness protection than prominent opponents of new conservation, and in favor of the published new conservation perspective but with less emphasis on increasing human well-being as a goal of conservation. Our results revealed differences between the debate on the new conservation in the literature and views held within a wider, but still limited, conservation community and demonstrated the existence of at least one viewpoint (in favor of conservation to benefit people but opposed to links with capitalism and corporations) that is almost absent from the published debate. We hope the fuller understanding we present of the variety of views that exist but have not yet been heard, will improve the quality and tone of debates on the subject.

Holmes, G., C. Sandbrook, and J.A. Fisher. 2017. Understanding conservationists’ perspectives on the new-conservation debate. Conservation Biology 31:353–363  doi: 10.1111/cobi.12811

Climate change and biodiversity loss in the Cape Floristic Region


Jasper Slingsby is the lead author on a recent paper in the Proceedings of the National Academy of Sciences describing some of the work he, John Silander, and others did as part of our recently concluded Dimensions of Biodiversity project. Here’s the abstract. Follow the links below to find the full paper and a story about it in UConn Today.

Prolonged periods of extreme heat or drought in the first year after fire affect the resilience and diversity of fire-dependent ecosystems by inhibiting seed germination or increasing mortality of seedlings and resprouting individuals. This interaction between weather and fire is of growing concern as climate changes, particularly in systems subject to stand-replacing crown fires, such as most Mediterranean-type ecosystems. We examined the longest running set of permanent vegetation plots in the Fynbos of South Africa (44 y), finding a significant decline in the diversity of plots driven by increasingly severe postfire summer weather events (number of consecutive days with high temperatures and no rain) and legacy effects of historical woody alien plant densities 30 y after clearing. Species that resprout after fire and/or have graminoid or herb growth forms were particularly affected by postfire weather, whereas all species were sensitive to invasive plants. Observed differences in the response of functional types to extreme postfire weather could drive major shifts in ecosystem structure and function such as altered fire behavior, hydrology, and carbon storage. An estimated 0.5 °C increase in maximum temperature tolerance of the species sets unique to each survey further suggests selection for species adapted to hotter conditions. Taken together, our results show climate change impacts on biodiversity in the hyperdiverse Cape Floristic Region and demonstrate an important interaction between extreme weather and disturbance by fire that may make flammable ecosystems particularly sensitive to climate change.

Slingsby, J.A., C. Merow, M. Aiello-Lammens, N. Allsopp, S. Hall, H.K. Mollman, R. Turner, A.M. Wilson, and J.A. Silander, Jr.  2017. Intensifying postfire weather and biological invasion drive species loss in a Mediterranean-type biodiversity hotspot. Proceedings of the National Academy of Sciences USA (early edition) doi: 10.1073/pnas.1619014114

The new game of Russian roulette for fire-prone ecosystems, UConn Today, 17 April 2017

Not every credible interval is credible

Lauren Kennedy and co-authors (citation below) worry about the effect of “contamination” on estimates of credible intervals.1 The effect arises because we often assume that values are drawn from a normal distribution, even though there are “outliers” in the data, i.e., observations drawn from a different distribution that “contaminate” our observations. Not surprisingly, they find that a model including contamination does a “better job” of estimating the mean and credible intervals than one that assumes a simple normal distribution.2

They consider the following data as an example:
-2, -1, 0, 1, 2, 15
They used the following model for the data (writing in JAGS notation):

x[i] ~ dnorm(mu, tau)
tau ~ dgamma(0.0001, 0.0001)
mu ~ dnorm(0, 100)

That prior on tau should be a red flag. Gelman (citation below) pointed out a long time ago that such a prior is a long way from being vague or non-informative. It puts a tremendous amount of weight on very small values of tau, meaning a very high weight on large values of the variance. Similarly, the N(0, 100); prior on mu; may seem like a “vague” choice, but it puts more than 80% of the prior probability on outcomes with x < -20 or x > 20, substantially more extreme than any that were observed.

Before we begin an analysis we typically have some idea what “reasonable” values are for the variable we’re measuring. For example, if we are measuring the height of adult men, we would be very surprised to find anyone in our sample with a height greater than 3m or less than 0.5m. It wouldn’t make sense to use a prior for the mean that put appreciable probability on outcomes more extreme.

In this case the data are made up, so there isn’t any prior knowledge to work from. but the authors say that “[i]t is immediately obvious that the sixth data point is an outlier” (emphasis in the original). Let’s take them at their word. A reasonable choice of prior might then be N(0,1), since all of the values (except for the “outlier”) lie within two standard deviations of the mean.3 Similarly, a reasonable choice for the prior on sigma (sqrt(1/tau)) might be a half-normal with mean 0 and standard deviation 2, which will allow for standard deviations both smaller and larger than observed in the data.

I put that all together in a little R/Stan program (test.R, test.stan). When I run it, these are the results I get:

         mean se_mean    sd    2.5%     25%     50%     75%   97.5% n_eff  Rhat
mu      0.555   0.016 0.899  -1.250  -0.037   0.558   1.156   2.297  3281 0.999
sigma   4.775   0.014 0.841   3.410   4.156   4.715   5.279   6.618  3466 1.000
lp__  -16.609   0.021 0.970 -19.229 -17.013 -16.314 -15.903 -15.663  2086 1.001

Let’s compare those results to what Kennedy and colleagues report:

AnalysisPosterior mean95% credible interval
Stan + "reasonable priors"0.56(-1.25, 2.30)
Kennedy et al. - Normal2.49(-4.25, 9.08)
Kennedy et al. - Contaminated normal0.47(-2.49, 4.88)

So if you use “reasonable” priors, you get a posterior mean from a model without contamination that isn’t very different from what you get from the more complicated contaminated normal model, and the credible intervals are actually narrower. If you really think a priori that 15 is an unreasonable observation, which estimate (point estimate and credible interval) would you prefer? I’d go for the model assuming a normal distribution with reasonable priors.

It all comes down to this. Your choice of priors matters. There is no such thing as an uninformative prior. If you think you are playing it safe by using very vague or flat priors, think carefully about what you’re doing. There’s a good chance that you’re actually putting a lot of prior weight on values that are unreasonable.4 You will almost always have some idea about what observations are reasonable or possible. Use that information to set weakly informative priors. See the discussion at https://github.com/stan-dev/stan/wiki/Prior-Choice-Recommendations for more detailed advice.

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Photos from Bonn

Christmas market in Bonn

Christmas market in Bonn, December 2016. Click on the photo to see the entire album on Flickr.

Late last November I visited Bonn to participate in a small workshop sponsored by the Crop Trust (https://www.croptrust.org/) intended to develop criteria to assess whether germplasm collections of crops and crop wild relatives are sufficient to meet the Millenium Development Goals. I was there not because I know a lot about crop germplasm (I don’t), but because my expertise in analysis of genetic structure in plant populations and my work on plant conservation genetics provided some (I hope) useful context for the discussions.

I didn’t have a lot of time to explore Bonn, but I did have a couple of hours on the afternoon I arrived and most of the morning on the day that I left. If you’d like to see the photos I thought were worth saving, click on the image above to visit a Flckr album where you can see them all.

I feel appreciated

Certificate of AwesomenessThis week the University of Connecticut expressed its appreciation for employees. I am nearing the end of my 31st year with the University, and I’ve heard through the grapevine that I’ll be receiving a “surprise” gift recognizing 30 years of service at a meeting I’m attending next week. On Tuesday, I presented a gift to an employee of The Graduate School recognizing 35 years of service as a state employee. I was surprised and gratified to receive the unofficial “Certificate of Awesomeness” pictured above from members of The Graduate School staff. I feel very appreciated – and fortunate to have been a part of UConn for more than 30 years.

It appears that I’m a New Conservationist

I recently discovered the Future of Conservation Project. It’s a project designed “to explore the views of conservationists on a range of issues, as a way of informing debates on the future of conservation.” As the About page says,

Recent debates about the future of conservation have been dominated by a few high-profile individuals, whose views seem to fit fairly neatly into polarised positions. In this survey, we are exploring the range of views that exist within the conservation movement globally, and how this varies by key demographic characteristics such as age, gender, geography and educational background.

The blue dots in the figure above are results from the 99 people who responded to the survey before me. Here’s how to interpret my results:

How to interpret your results

Your position is weakly negative along the people & nature axis and weakly positive along the conservation & capitalism axis.

Your position on the two axes above reflects your survey answers. A move from left to right along the horizontal axis (people/nature) implies a shift from seeing conservation as a means of improving human welfare to conservation for nature’s own sake.

The vertical axis (conservation & capitalism) indicates a spectrum of willingness to embrace markets and capitalism as conservation tools: the higher up the graph your score is, the more pro-markets it is. This places you in the top left quadrant of the graph – a position suggesting your views on these particular dimensions of the debate are most closely related to those of ‘new conservationists’ as set out in the literature.

Your thinking most closely aligns with: New Conservation

Central to the ‘new conservation’ position is a shift towards framing conservation as being about protecting nature in order to improve human wellbeing (especially that of the poor), rather than for biodiversity’s own sake. ‘New conservationists’ believe that win-win situations in which people benefit from conservation can often be achieved by promoting economic growth and partnering with corporations.

Although new conservation advocates have been criticised for doing away with nature’s intrinsic value, key authors within the movement have responded by clarifying that their motive is not so much an ethical as a strategic or pragmatic one. In other words, they claim that conservation needs to emphasise nature’s instrumental value to people because this better promotes support for conservation compared to arguments based solely on species’ rights to exist.

If you’re interested in taking the survey, here’s the link: http://www.futureconservation.org/.

A few photos from Dublin


I visited Dublin a couple of weeks ago for meetings of the Deans and Directors of Graduate Studies (DDoGS) from Universitas 21 (http://www.universitas21.com/article/research/details/55/deans-and-directors-of-graduate-studies-ddogs). The meeting began on 20 March with a workshop on “The Future of the Doctorate.” It continued on 21 and 22 March with discussions of graduate research project grants, the possibility of a 3-MT competition for master’s students, plans for a supervisor development project,1, and a discussion of wellness and mental health. This was the fifth DDoGS meeting I’ve attended, and I’ve always found them useful.

There is a direct flight from Hartford to Dublin. I left in the evening on 18 March and arrived in Dublin a little after 5:00am on 19 March. Since there weren’t any activities until 6:00pm that night, I spent most of the day on the 19th wandering around Dublin taking photographs. I also spent the day on 23 March taking photographs, since I didn’t return home until the 24th. The photograph above is of Temple Bar, one of the most famous pubs in Dublin. If you’d like to see more of the photographs I took while I was there, here’s a link: https://www.flickr.com/photos/billandkent/albums/72157679862838432.

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The beauty of fynbos

The beauty of our fynbos from CapeNature on Vimeo.

In case you’ve ever wondered why I have spent so much time working in, thinking about, and writing about Protea this video from CapeNature will give you a bit of a clue. The fynbos is a very interesting place. It has an enormous diversity of plants, many of which are found nowhere else in the world, and much of that diversity is concentrated in a relatively small number of big evolutionary radiations, one of which is Protea.1 One of my students,

Kristen Nolting (@KristenNolting on Twitter) pointed me to this video. Thanks, Kristen.

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A new phylogeny for Protea

Protea compacta

Protea compacta near Kleinmond, Western Cape, South Africa

The genus Protea is one of the iconic evolutionary radiations in the Greater Cape Floristic Region of southwestern South Africa. Its range extends north through Mozambique into parts of central Africa, but the vast majority of species are found in South Africa. From 2011-2014 we collected samples from most of the South African species (59 in total), and for most of the species we collected samples from several individuals from different populations. Over the last couple of years, we extracted DNA, built libraries for next generation sequencing using targeted phylogenomics, and constructed a highly-resolved estimate of phylogenetic relationships in the genus. The paper describing our results is now out in “early view” in American Journal of Botany. Most species from which we have multiple samples are supported as monophyletic units, and most relationships we identify are strongly supported (> 90% support in ASTRAL-II and SVDquartets analyses). We use the species tree from our data as a backbone to provide reliable estimates of relationship for additional species included in a paper by Schnitzler and colleagues for which we did not have samples.

Mitchell, N., P.O. Lewis, E.M. Lemmon, A.R. Lemmon, and K.E. Holsinger.  2017.  Anchored phylogenomics improves the resolution of evolutionary relationships in the rapid radiation of Protea L. American Journal of Botany doi: 10.3732/ajb.1600227

Conservation, economic inequality, and privilege

Increased equity and pro-poor actions are not only moral issues to be kept in mind by conservationists. They are, rather, central to the larger goal of protecting the planet. – Bill Murdoch

In the past 15-20 years, conservation biologists have become increasingly aware that successful conservation efforts require the support and involvement of local communities, but only more recently have we become fully aware that getting that support and involvement requires that we pay attention to what communities need, not only to what we want. Reducing economic inequality, and in particular improving the lives of those in poverty, is not only the right thing to do on its own terms. It’s the only way we can protect the natural systems we can care about in the long term.

In Fall 2015, I discussed some of these issues in my graduate course in conservation biology. The problem is that it’s easy to say the “right” words and to congratulate ourselves for our wisdom and generosity. It’s harder to see how the attitudes those of us who live in relatively prosperous communities are influenced by the economic privileges we have. Those privileges are part of the reason it’s hard for us to understand farmers, ranchers, and oilmen who seem to have little regard for the land. I grew up among farmers and ranchers in southern Idaho, and the people I knew care as deeply about the land as I do. The difference? They draw their livelihood directly from the land, and their livelihood is less secure. Not unreasonably, they focus on immediate needs,1 not far-off benefits.

Fortunately, I had a very talented teaching assistant for the course, Holly Brown. She had the idea of using a “privilege walk” to illustrate the ways in which we – graduate students and faculty at UConn – are privileged when compared to many of those living in areas where conservation action is needed. Holly, Ambika Kamath, and Margaret Rubega describe the exercise in a recent article in Conservation Biology. This anonymous comment from one of our students was particularly striking:

The main thing I took away was that, when it comes to issues that are controversial (including climate change or biodiversity preservation), approaching those who might oppose ecologists with an understanding of my own privilege and how it differs from the background of others can help me to open myself up to innovative solutions, instead of imposing my beliefs on others.

If you teach a course in conservation biology, I encourage you to read Holly’s article and use some of the ideas in it the next time you teach your course.

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