Hi! I’m Tom, a lecturer at Cardiff University, assistant editor at Journal of Animal Ecology, and a self-described macroecologist. I’m writing on the JAE blog to promote the wonderful subfield of macroecology. JAE is packed with a wealth of great animal macroecology studies. In addition, there is a British Ecological Society Macroecology Special Interest Group Annual Meeting (that’s a serious mouthful) coming up in July. Tickets are only on sale until the end of this month! YOU should come! Here is the link to tickets.

To convince you, I’d like to showcase a few recent papers from JAE that exemplify the macroecology-mindset. Before I do that, however, what is macroecology? It is now an in-joke within the field to ask this question (What is macroecology?)! Ask a roomful of macroecologists to define the field and you’ll get 100 different answers. This highlights the diversity of ecological disciplines and techniques that macroecology draws upon. Despite this, our macroecologist-packed room would likely agree on a few key themes. 

The first unifying theme is that macroecology is the ecology of large scales (The what, how and why of doing macroecology). We macro-folk like to go BIG. We focus on collecting and analysing data at large spatial scales (across continents or the entire globe), large temporal scales (from decades to millennia to millions of years), or at large taxonomic and phylogenetic scales (incorporating as many taxa into our work as possible). Sound familiar? Maybe you are already a macroecologist and you didn’t realise! Working at a large scale on at least one of these dimensions qualifies you as a macroecologist in my book.

The second unifying theme is the search for general patterns (The what, how and why of doing macroecology). Ecology is complicated and varies from place to place, from centimetre to centimetre, and from moment to moment. By encompassing large spatial, temporal or taxonomic scales, macroecologists try to “average over” the minute details of specific case studies. By doing this, we try to find the general trends and rules that Life adheres to. Whether we are achieving this or not is a big question… but hang out with a macroecologist long enough and you’ll hear some talk of “general principles”.

On with the showcase:

First up is a recent study by Moura et al. Mario Moura and colleagues were interested in the anti-predator defence mechanism called autotomy. Autotomy happens when the predated individual choses to lose a body appendage to their predator, rather than be eaten entirely. By studying this phenomenon, the authors argue that we can better understand the complexity of species interactions. To do this, the authors studied over 8000 museum specimens of snakes and amphisbaenians across South America and Africa. They then linked the geographic locations that these specimens with measures of body size and various climatic datasets. They were more likely to find evidence of autotomy in larger specimens from canopy dwelling species living in warmer climates. The authors linked these correlations to a suite of ideas on predator-prey interactions. Check out the paper, it’s a really great example of how museum collections can advance our understanding of ecology and push forward the large spatial and taxonomic scales that macroecology investigates.

The second paper I’ve selected was written by Armelle Lajeunesse and Yoan Fourcade. In their paper, the authors analyse a huge dataset of species spatiotemporal records from the Global Biodiversity Information Facility. This dataset ticks all of the macroecology boxes: large spatial, taxonomic, and temporal scales. The authors used these data to detect signals of ecological reorganisation following climate change. As each of their species records was linked with latitude-longitude coordinates and date stamps, they could estimate the kinds of thermal environments that the species had experienced. By doing this, the authors could calculate a temperature index for each species (is it a hot specialist? A cold specialist?) and track changes in these temperature indices for entire multi-species communities over a 30 year period. Depressingly, but importantly, their analyses revealed shifts in nearly all taxonomic groups from cooler to hotter temperature indices. Perhaps an example of macroecology revealing the “generality” of the temperature-ecology relationship… The hot specialists are beginning to take-over! I also really appreciated figure 3 as a textbook use of the forest plot to summarise complex results. 

The third paper I’d like to highlight is really cool. It’s by Michael Moore and Faiza Khan and tests the hypothesis that animals with large wings will do better in high altitude locations as they can generate more lift and reduce the energetic costs of flying. This hypothesis has been explored in detail for birds, but not for organisms like insects who, as ectotherms, have very different energetic budgets compared to warm-blooded organisms. The authors collated publicly available data on dragonfly wing size and geographic distribution and found positive relationships between wing size, maximum elevation lived at, and elevational breadth, across 302 dragonfly species. Another great example of how macroecology can find big – and potentially general – answers to ecological questions with publicly available data.

I’d encourage you to check out these macro papers, and to come and say hi at the BES Macroecology 2023 meeting! It’ll be in Birmingham, UK, on July 12-13th. Book your place here before May 31st 2023! Come and say hello – if you can bring me a macroecology themed ant (Hymenoptera: Formicidae) fact the beers/coffee/juices will be on me!

Tom