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.