Caveats and considerations for future research
In this study, we propose that the lack of preprocessing in orchid occurrences data brings uncertainty to the models. Classification by lifeforms increases accuracy in orchid SDMs. Although this is only a rough classification method based on physiological differences in orchids, we encourage researchers to attempt a further decomposition of it. It has been shown that distinct environmental preferences exist for different rooting systems of orchids (Stipkova et al., 2021). It would be a meaningful extension of this study to consider the physiological intervals of species as limiting thresholds to regulate environmental variables. For some endangered species, it is more significant for orchid biodiversity conservation to strengthen the correlation analysis with the environment, improve the resolution of environmental variables, and establish more accurate mathematical models. Another contribution of this study is to propose a method to quantify human activities in SDMs, which, although not shown to be important in our models, will be a reference for species conservation studies in other regions because the indicator we provide is replaceable. The final issue we would like to raise is the scale of applicability of the orchid SDMs. Research has shown that different spatial scales have a significant impact on the models’ accuracy and suitability maps (Chen, 2023). What spatial scale for orchids could best optimize the performance is a worthy concern for future orchid conservation efforts. In addition, some results with different appearances in our model strategies may be influenced by the statistical algorithm or the sample size, which will be worthy of verification in a subsequent study. It could be seen that there are distinct differences between different model strategies in predicting suitability maps even with the same species occurrence dataset, environmental information, and resolution. Therefore ground-truthing validation of orchid SDMs would be a meaningful research direction.