Most of the abstract seems to be saying that unlike men, women can form tight cliques with other women, which gives them an advantage (the 2.5x boost) apparently unavailable to men.

But they also end with "Women who have networks that resemble those of high-placing men are low-placing, despite having leadership qualifications comparable to high-placing women." As they don't otherwise mention leadership qualifications, nor even define the term, it's unclear what's being hinted at here.