Spatio-temporal dynamics of the invasive orchid Oeceoclades maculata (Orchidaceae), in four different habitats in southeast Chiapas, Mexico

The expansion of invasive species is a global concern. Within the Orchidaceae there are a number of invasive species. One of the most widely distributed invasive orchids in Mexico is Oeceoclades maculata (Lindl.) Lindl. By examining the population dynamic variations of an invasive species in its range of expansion, we can identify the factors that have contributed to that variation. Life Table Response Experiments (LTRE) were used to describe the dynamic of four populations of O. maculata in different ecosystems in south Chiapas, Mexico. Our goals were to quantify the contributions of differences between years and sites, and their interactions, to overall differences in population growth rate (λ), and to underlying vital rates. Fertility, survival and growth made the largest contributions, both positive and negative, to annual differences in λ. Spatial variations in λ were also found. The largest plants (S3 and S4) made the contributions of greatest magnitude each year and in each site. In seven of eight cases, the inclusion of the interaction term gave a better estimate of the population growth rate. This investigation highlights the need for taking into account life-history variations at different scales when the research goal is to study expansion of an invasive species in a heterogeneous landscape. The usefulness of LTRE studies was also demonstrated to better understand the natural history of the species and thus lay the groundwork for planning efficient management strategies, either for the conservation of rare, endangered species, or for the control of invasive species.