For our week on competitive theory, we read two papers on the interactions between sessile (i.e. stationary, immobile) organisms. Almost 50 years apart, both Connell (1961) and Wulff (2008) utilize experimental manipulation in natural systems to assess species interactions. Competitive theory centers on similar species due to their diet, phylogenetic closeness or function fighting to utilize the same resource and can often lead to the exclusion of the less competitive species. Each of this week’s studies builds upon a profound amount of natural history to then test theory on which resource or phenomena may be lead sessile organisms to organize in space.
Connell explores the stark spatial segregation of two barnacle species, an upper resident Chthamalus stellatus and a lower resident Balanus balanoides along Scotland’s rocky intertidal shore. First, Connell removed barnacles to look at each single species along the full intertidal gradient. He found that Chthamalus was able to survive in a much broader environmental area than observed (fundamental niche > realized niche). Balanus, the faster growing better crowd competitor, could not exist in upper bands of the zone due to environmental pressures (heat that led to desiccation). Interestingly, with the introduction of a predator or a parasite, these competitive interactions appeared to decrease.
Wulf’s study, however, observes collaborative interactions between sponges focusing on a poor competitor, Lissodendoryx colombiensis. Sponges uniquely form diverse assemblages that grow on top of each other, and seem to defy standard competitive theory. Wulf showed that crowding of sponges on and around Lissodendoryx deterred predation pressure from the starfish, Oreatus reticulatus.
A fascinating similarity between these two papers is they are both single-authored. Are there perceptions of a single-author? Does this show more initiative and independence of the scientist? Or does singularity in authorship show a lack of collaborative spirit, often necessary to link natural history and ecological mechanisms? Certainly both these projects took an immense amount of work beyond the author in data collection, processing and organization, and write-up. Yet, perhaps these tasks don’t seem to warrant authorship. I think this brings up a unique point about coordination vs. collaboration, and how lead authors may work with many, and yet be the sole driver of their research.
I was particularly struck, that not only is the Wulff paper single-authored, but the ten self-cited papers are single-authored as well. Standards of authorship operate differently among labs. For instance, dissertation work may be single-authored completely or be required to include the graduate advisors. In Dr. Wullf’s case, it seems to be the former, as her graduate students also produce single-authored work. I think this single-authorship, and perhaps the attitude behind it, maybe a component in how Dr. Wulff is so successful (R1 professor, Smithsonian fellow, and prolific publishing), despite the notorious leaky pipeline for women in her field.
References:
Connell, JH (1961). The influence of interspecific competition and other factors on the distribution of the barnacle Chthamalus stellatus. Ecology 42, 710–743 .
Wulff, JL (2008). Collaboration among sponge species increases sponge diversity and abundance in a seagrass meadow. Marine Ecology, 29(2):193-204.