Predicting distributions of pine and oak considering interspecific competition and dispersal ability
Studies to predict future plant distributions have been conducted for conservation of plant species. One of the problems in the studies is that more than two plants inhabit in the same area when prediction proceed separately. Accordingly, researchers studied interspecific competition by comparing habitat suitability of each species. However, plant distribution is affected by not only interspecific competition but also dispersal ability. Therefore, it is necessary to predict plant distribution considering interspecific competition and dispersal ability.
The objective of this study is to improve accuracy of distribution prediction by considering interspecific competition and dispersal ability. Therefore, we used Pine, a weak competitor, and Oak, a strong competitor and selected an island composed of only Pine and Oak. We built three steps to predict future distributions. First, we estimated habitat suitability from the present distribution of two species using environmental variables. Second, we analyzed the past distribution change at ten-year interval. A multiple logistic regression analysis pooling distance from Oak to Pine and habitat suitability difference between two species was undertaken to calculate replacement probability of Pine by Oak. Third, we predicted future distribution of Pine and Oak using present distribution, future habitat suitability, and replacement probability of Pine by Oak.
As a result, different from other researches which used only habitat suitability for prediction of future distribution of Pine and Oak, we predicted that Pine will inhabit at island until 2055. Future replacement probability of Pine by Oak is highly affected by distance from Oak to Pine. In addition, habitat suitability of Pine and Oak is significantly affected when the distance from Oak is similar.
In conclusion, dispersal ability of plant should be considered as an important variable to predict future distribution of plants. In other words, we should consider the dispersal ability to predict distribution of plants more accurately. In this study, we used distance from Oak to each Pine to consider the dispersal ability. However, more researches need to be conducted to reflect the plant dispersal ability. Furthermore, for practical forest management, we should conduct analysis on more than two plants.