Unprotecting the rare species: a niche-based gap analysis for odonates in a core Cerrado area



Aim  We evaluated Odonata distribution data and predicted the compositional resemblance based on niche-based species distribution models to analyse the following questions: (1) How is estimated species richness distributed, and how can it be preserved under the actual network of conservation units (a gap analysis approach)? (2) How is the estimated odonate beta diversity distributed, and is there a better distribution of conservation units (a priority setting approach)? (3) Is the probability of being under protection a function of the potential species range size? and (4) Will the current conservation network proposals protect odonate taxa?

Location  Central Brazil in a core Cerrado area.

Methods  We generated odonate species distribution predictions based on MaxEnt and maps derived from estimated species richness, beta diversity and gap analysis for all species predicted to occur in the study area. Then, we compared these maps with current conservation units, land-use patterns and proposals for the establishment of conservation units.

Results  Raw odonate species records provided limited utility for setting conservation priorities without the use of niche-based models. However, area under the receiver operating curve (AUC) values were characterized by substantial variation that was related to the number of records. No current conservation units overlapped the areas with higher predicted richness and beta diversity, and in general, conservation units were not preserving restricted/rare species. There was a direct linear correlation between species range size and the proportion of its range protected in the current network of conservation units. Finally, we identified three areas with high odonate beta diversity where conservationist actions should be implemented.

Main conclusions  Current conservation units and future suggested areas do not overlap regions with high conservation values for odonates. Conservation units protect species at random, and the level of protection has a direct relationship with species range size; thus, wide-range species are expected to be more protected than restricted or threatened species.