MaxEnt's parameter configuration and small samples: are we paying attention to recommendations? A systematic review

Environmental niche modeling (ENM) is commonly used to develop probabilistic maps of species distribution. Among available ENM techniques, MaxEnt has become one of the most popular tools for modeling species distribution, with hundreds of peer reviewed articles published each year. MaxEnt's popularity is mainly due to the use of be always appropnate because it can Produce non-optimal models; when dealing graphical interface and automatic paramreesetenrceconfiguration capabilities. However, recent studies have shown that using the default automatic configuration may not appropriate because. particularly heti d.th a small number species p ealing wi 1 number 0. points. Thus, the recommendation is to evaluate the best Potential combination of Para c meters (feature lasses and regularization multiplier) to select the most appropriate model. In this work we reviewed 244 articles Published between 2013 and 2015 to assess 'whether researchers are following recommendations to avoid using the default parameter configuration when dealing with small samPle sizes, or if they are using MaxEnt as a black box tool. Our results show that M only 16% of analyzed articles authors evaluated best feature classes, in 6.9% evaluated best regularization multipliers, and. ln.a meager.. 3.7% evaluated simultaneously.both parameters before producing the definitive distribution model.We analyzed 20 articles to quantify.the potential differences in resulting outputs when sing software default parameters instead of the alternative best model. Results from our analysis reveal important. differences between the use of default. parameters and the best model approach, especially in the total. area identified. as suitable for the assessed sPecies and the specific areas. that are identified as suitable by both modelling approaches. These results are worrying, because publications are potentially. reporting over-complex or.over-simplistic models can.undermine the applicability of their results. Of particular. importance are studies usedto inform policy.malung. Therefore, researchers, practitioners, reviewers and editors needtoibse very judicious when dealing with MaxEnt, particularly when the modelling process is based on small sample sizes.