2021

2021 in review

While COVID19 (and its many variants) continued, the world began to return to normal for many countries and cities in 2021. In Hong Kong however, 2021 felt like a rerun of 2020. In both years we've been unable to leave the city without enduring long quarantines in hotels (or government quarantine centres). While the lack of travel has been stifling, other elements of life in the city continue relatively normally. I miss my family and friends back in the US, and elsewhere in the world. But otherwise, I'm also happy spending time at home and in the lab.

The lab has this year has grown rapidly in size, and very quickly. John Allcock, Even Yee Man Leung, Kelly Shiu, and Portia YH Wong all joined the lab as postgraduates. Shihan Susie Sun started a postdoc in the group. And Catherine Hai, Emily Jones, Joey So and Sam Webster all became research assistants. We've also had departures - Sharne McMillan received her PhD and took a position at the Yorkshire Wildlife Trust. With no ability to travel, our large lab, and lots of friendly folk, the lab has become a real source for fun and relief from the madness of our current covid-run world (at least for me!). We've had pizza picnics, monthly bday parties, African food lab lunches, overwintering butterfly watches, and a writing retreat in the peaceful forest of the Kadoorie Centre.

Early this year we received funding from the Research Impact Fund (RGC) to study "pangolins and pathogens". This is an exciting project that examines the pangolin trade and possible associated pathogens, in collaboration with the School of Public Health at HKU. Otherwise, the lab has been very busy working on a range of projects; modelling climate change responses of insects, studying snakes, estimating population sizes of rare mammals, and tracking wildlife trade (among other things). In fall of 2021 I also took on a new position as the Associate Dean (Teaching & Learning) of the Faculty of Science. It's been a busy year!

In what has now become a tradition, and an opportunity for me to reflect, I present to you here the backstory on a few of the papers that came out of the lab in 2021:

Predators and climate change both affect prey thermal biology

Felix Landry Yuan began his PhD at HKU working with Prof. Masami Hasegawa (Toho University) on the lizards of the Izu Islands. Masami has studied predator-prey dynamics of skinks and lizards across the islands for decades. And Felix was eager to study thermal biology aspects of these species interactions - Masami was generous and eager to collaborate. In 2017 Masami visited the lab at HKU (see photo) and in 2019 Tim and Felix visited Masami during a field course on Sado Island.

Felix spent multiple field seasons on the Izus with Masami. He raced skinks down a race track and measured thermal performance at variable body temperatures. Masami had also collected similar data for snakes. Body temperature data were also collected by Masami and his team between 1981 to 2019. Remarkably, on islands where the snake predator was present, the lizards' foraging body temperatures were approximately 3C higher than lizards where there were no snakes. Additionally, we found that climatic warming over that period coincided with an increase in lizard body temperature by over 1C. And finally, Shun Ito conducted an analysis demonstrating that snakes resulted in a selection for longer hind leg length on islands where there are snakes present.

A couple things amaze me about this paper. First and foremost, the fact that Masami collected body temperature of the lizards in the 1980s is incredible. And we were extremely fortunate for his foresight here. In fact, he wasn't thinking about climate change when he collected that data. He was just curious. But that curiosity is so fundamental to everything we do in ecology and conservation science. The second thing that still surprises me is just how strong the effects were. We initially hypothesized that we might see some effects of climate and predators on skink body temperatures... but none of us really expected to see such strong effects. Because of the complexity of predator-prey interactions and underlying thermal biology effects for multiple ectotherms, we don't know how future climate change might affect these species. It might help the skinks, but it also might give a "leg up" to the snake. Felix's research highlights the complexity of future species interactions like this in a warming world.

See paper in Ecology Letters and coverage in the NY Times

Valuing urban and peri-urban gardens for butterflies

Fiona HY Lo is a graduate of the Msc in Environmental Management program at HKU. For her thesis she wanted to do a study on butterflies and butterfly gardens. The topic has recently become a popular one in Hong Kong and there is considerable interest in improving urban habitats for biodiversity and butterflies in particular. Fiona and I discussed sampling strategies and ways to get good butterfly data. One of the things that has interested me about Hong Kong urban butterflies is that there are a lot of them... but whether they're using resources in urban areas or just passing through still remains a largely open question. Toby Tsang has also long-studied this topic so he soon too got involved in the study.

Fiona put a lot of time into intensively sampling ten butterfly gardens across Hong Kong spanning urban and peri-urban sites. Importantly, she collected both diversity and behavioral data. And then Toby used his statistical wizardry to put all the data together and make sense of it all. We found that diversity correlated with surrounding NDVI... but that the behavioral diversity metric that also correlated with NDVI was "flying across". This is an indication that the higher diversity in those gardens has less to do with the garden itself but rather the surrounding landscape and butterflies passing through the gardens. We also found that "nectaring diversity" correlated with the floral abundance. Some butterflies do then appear to be using floral resources. The work highlighted the importance of considering behavior and presents a useful way for untangling these processes by breaking down diversity into behavioral components.

See paper in Ecological Applications

Local adaptation to habitats structures tropical climate change responses

This paper was ten years in the making. When I was a postdoc at UCLA in 2010-2011 I got involved in a proposal to study climate change adaptation in Central Africa. We proposed a project to study adaptation and plasticity in Bicyclus dorothea in Cameroon using a common garden experimental design. Little did we know at the time how difficult this would be logistically! Michel Dongmo joined the team soon after the proposal was funded and got to work collecting the data we needed. However, significant logistical challenges presented themselves... for one, the butterflies didn't want to mate in the lab. It took some time but eventually Michel overcame the obstacles.

We found that when comparing ecotone (variable climate and habitat) and forest (more stable climate) populations of B. dorothea, the thermal tolerance (ctmax) was higher for ecotone populations. This was true even after rearing both populations of multiple generations in the same conditions. This demonstrated that there was local adaptation and that climate change vulnerability is unlikely to be compensated for through plasticity (at least not immediately). And this conclusion then adds to the mounting evidence that tropical forest ectotherm populations may be especially vulnerable to climate change.

There are a lot of things that I like about this paper. First off, it (partially) answered a question I was curious about since back in my PhD days. Second, Michel was never deterred despite a number of setbacks. It took us ten years because of the difficulty of field conditions, lack of baseline natural history, and a variety of other administrative/logistic issues. But Michel stuck to it and got it done. Finally, the review process was immensely helpful. The reviewers at Biology Open identified things we missed in the initial draft and were able to highlight the truly novel findings from the work. Thanks reviewers! We still have a ways to go regarding adaptive and plastic responses of ectotherm thermal tolerance to climate change. Keep an eye on this space. But this paper is a strong first direction in a research pathway I've been wanting to develop for some time.

See paper in Biology Open and profile on Michel

Concluding thoughts…

When I was doing my PhD I usually arrived at my office in Herrin Hall (Stanford) early each morning. Not many other students were there until later. But my friend Priya Iyer was nearly always there. I would frequently stop by her office for a chat, or she would stop at mine. We would discuss all sorts of things (cultural differences, food, yesterday's seminar) and the distraction was always welcome. Her sharp insights into ecological and evolutionary theory, and her clarity in these insights, were just so impressive. The only thing that matched this was her overwhelming positivity and generosity. After we both left Stanford in 2009 (Priya was the first in our cohort to graduate) and 2010 we lost touch. But in 2018 I happened to be visiting Bangalore for a conference. I shot her an email and asked if she had time in the week I was there to meet. She let me know she would be busy because her sister was getting married. So, then she invited Marie and me to attend the wedding! It was a truly amazing experience, full of love, friendship, beauty, and phenomenal food. Because Priya was so busy with the wedding we only had a few minutes to actually meet and catch up with each other - and it was awesome. Priya passed away in Jan 2021. The Life of Science paid tribute to her recently and so clearly detailed how much Priya influenced and mentored science students in India. And indeed, we do absolutely "need more people like Priya in the sciences".

I don't know what 2022 will look like but I suspect it will look a lot like 2021. COVID restrictions in Hong Kong are tightening and travel not likely, and certainly not easy. But I'm grateful to be surrounded by enthusiastic, caring, and bright students and research staff in the lab. And I'm particularly grateful for Marie and the beasts during quiet Lamma weekends. Wishing you a great 2022.