'lessen diversity' is correct and can be used in written English.
You can use it to describe a situation in which a group becomes more homogeneous due to changes that reduce the variation of its members. For example, "The closure of the local factory had a negative effect on the town, as it resulted in a lessening of diversity among its population."
At the same time, he is worried this move will lead to rapidly rising rents, and lessen the very diversity of our neighbourhoods, places, and people which makes urban environments attractive.
Generally, scientists believe that lower genetic diversity lessens a population's chances of survival.
We also found that diversity was lessened in the higher elevations, due to rapid growth and exclusion by the planted S. alterniflora in conjunction with the native P. australis.
Diversity is a major factor that promotes system stability [33], loss of diversity thus lessens the protective effects of the microbiome and renders patients vulnerable to infection.
By measuring achievement of educational institutions in part by applicant tariff scores, the diversity of talent is hugely lessened.
And they love to propose strategies for lessening it: affirmative action, the celebration of diversity, the promotion of a culture of respect.
In addition, to lessen the influence of large inversions on estimates of genetic diversity and population structure, we estimated nucleotide diversity and pairwise FST excluding inverted arms for a subset of populations with larger sample sizes (inversion presence/absence is given in Table S4).
Meanwhile, a group of Republican Senators has raised an alarm about "undermining the diversity of the Federal contracting base and lessening competitive pressure on larger Federal contractors".
Yes, they make a solid case in favor of diversity and show the powerful way inclusion can lessen bias.
"The diversity of people, both incomes and interests, has lessened," she said, "and we have more of what we used to call upwardly mobile people, who shop online or drive to malls, or get in cabs and go to Barneys".
