Figure 2 in "One is the loneliest number"; are we witnessing the death throes of the single-author research paper in the field of biological invasions?

Figure 2. Changes in % of research papers published over time by single-authors (white circles and grey line) and four or more authors (black circles and black line) in issues of (a) BioInvasions Records, (b) Aquatic Invasions and (c) Management of Biological Invasions.