Disassembly basically means the loss of species from a community. Because plants and pollinators are linked to one another (plants need pollinators to help facilitate their reproduction, and pollinators need pollen and nectar from plants for food), the loss or reduction of a plant species can lead to the loss of one to many pollinator species and vice-versa.
Until recently, it was thought that bees that visit a lot of plants- generalists- were the keystone species in these linked plant-pollinator networks. A recent study in the American Naturalist found that abundance- the total number of a species- was the most important force affecting disassembly. This means that the most common species are able to persist, even in the face of habitat alteration by humans.
Another important factor is how linked a species is. Linkage is related to both how many plant species they visit, and how abundant the species is, which increases the chance that they are seen visiting different plants. Highly linked species help the species with low links because they visit plants that might be important to rare species, helping them hang on. Nevertheless, in human-altered landscapes, species with low abundance, linkage, and diet breadth may still be lost, while the abundant bees will be able to persist.
Winfree, Rachael, et al. “Species Abundance, Not Diet Breadth, Drives the Persistence of the Most Linked Pollinators as Plant-Pollinator Networks Disassemble.” The American Naturalist 183.5 (2014): 600-611.