engineers does not necessarily always have high abundance. Although their effect is more easily identifiable and more often a species with greater density and large per capita effect, species with smaller abundance can still have great impact. A prime example being the mud shrimp species Biffarius filholi, an ecosystem engineer with a small population density, but were evaluated to affect the temporal and spatial growth of macrofauna with their burrow structures. The presence of some ecosystem engineers has been linked to higher species richness at the landscape level. By modifying the habitat, organisms like the beaver create more habitat heterogeneity and so can support species not found elsewhere. Thoughts may be that similar to other umbrella species by conserving an ecosystem engineer you may be able to protect the overall diversity of a landscape. Beavers have also been shown to maintain habitats in such a way as to protect the rare Saint Francis' satyr butterfly and increase plant diversity. Biodiversity may also be affected by ecosystem engineer's ability to increase the complexity of processes within an ecosystem, potentially allowing greater species richness and diversity in the local environments. As an example, beavers have the capacity to modify riparian forest and expand wetland habitats, which results in an increase of the diversity of the habitats by allowing a greater number of species to inhabit the landscape. Coral-reef habitats, created by the ecosystem engineer coral species, hold some of the highest abundances of aquatic species in the world. Controversy However, there is controversy when using the term "ecosystem engineer" to classify a species because it can be perceived as a "buzz word" to the ecological science community. The use of the term "ecosystem engineering" suggested that the species were intentionally and consciously modifying their environment. There's also an argument to say that the ubiquity of ecosystem engineers translates to all species being ecosystem engineers. This would invite more ecological research to be done to delve into the classification of an ecosystem engineer. The generality and the specifications of identifying an ecosystem engineer has been the root of the controversy, and now more research is being conducted to definitively classify and categorize species based on their impact as an ecosystem engineer. Classification Ecosystem engineers do have their general types, allogenic and autogenic, but further research has suggested that all organisms can fall under specific cases. It was proposed that there were six specific