Island Biogeography (Size and Isolation Determine Diversity)

MacArthur and Wilson's equilibrium theory models species richness through the balance of immigration and local extinction. Island area and isolation can influence those rates under the model's assumptions, alongside the available source pool and local conditions. An equilibrium number can coexist with turnover in species identities. Size and isolation are not the sole determinants of diversity.

The equilibrium model asks why the number of species can remain roughly stable while the identities of those species change. Arrival adds species; local extinction removes them. Area and isolation influence these processes under the model's assumptions, but the balance also depends on the available source pool and local conditions. A stable total therefore does not imply an unchanged community or the absence of ongoing losses.

For a team or learning community, the most useful analogy separates entry from retention. Inviting different perspectives does little if meetings make those perspectives impossible to express or maintain. Conversely, a supportive internal environment can remain narrow if it never encounters relevant outside ideas. Investigate both flows. Ecological theory does not show that larger teams automatically become more diverse, or that bias and power can be ignored when explaining social homogeneity.

When to use it

When organizational diversity is lower than desired despite good intentions; when innovation has stalled in an isolated team; when understanding why some markets or communities have more variety than others; when designing environments that naturally produce and sustain diversity.

How it can help

As an organizational analogy, examine both access to new perspectives and the conditions that allow them to remain usable. Reduce relevant barriers, provide opportunities for participation, and inspect whether unfamiliar evidence can affect decisions. Increasing headcount or outside contacts alone does not guarantee diversity.