Expanding the energy–stability–area model: density dependence in voluntary membership associations in the early twentieth century

Recent research applying the energy–stability–area (ESA) model to politically oriented, federated voluntary membership associations in the late nineteenth and early twentieth centuries has found that these organizations had additional capacity for membership. Yet, this approach does not tell us whether associations’ organizational densities restricted the growth and formation of new federated chapters because of density dependence, a finding common in modern ESA studies. Furthermore, it is not clear whether other voluntary associations, such as fraternal orders, faced similar challenges. Here, we begin to explore these questions by examining whether federated, political and non-political voluntary associations faced density dependence in both membership and the number of affiliated organizations at the state level. We find evidence that density dependence was a common concern for voluntary associations of all types. Both in terms of the number of local-level federated groups and, to a lesser extent, membership, these groups were so successful that environmental resources eventually limited their growth during this pivotal era for the development of pressure groups and civic participation in the USA.