Shifts in plant‐invertebrate interactions between wild and ex situ conservation populations of a critically endangered tree

Abstract

Abstract Ex situ conservation is an effective approach to prevent the extinction of endangered species. Biotic interactions (e.g. herbivory and pollination) are critical to ex situ conservation success, including plant establishment, survival and reproduction. However, shifts in biotic interactions between wild and ex situ populations are still poorly understood. We compared herbivory and pollination characteristics between the only wild population (WP) and three ex situ populations (LP, local population, nearby WP; NP, north population, ca. 850 km; and SP, south population, ca. 750 km) of a critically endangered tree species (Sinojackia huangmeiensis) to explore the latitudinal changes in plant‐invertebrate interactions. Larvae of the Limacodidae family were the dominant herbivores in WP, LP and NP, while the only herbivore observed in SP was snail. Compared to WP, the leaf herbivory rate was unchanged in LP but decreased in NP and SP. Leaf defence traits (total phenols, tannins, leaf thickness and leaf dry matter content) increased or remained unchanged in the three ex situ populations. A pollinator (Apis cerana) of S. huangmeiensis was present in the four populations. NP and SP lacked some pollinators that were found in both WP and LP, but they shared one pollinator that was not observed in WP and LP. The pollinator visiting frequency increased in SP, while it did not change significantly in LP and NP. Synthesis and applications. Our results suggested that both herbivory and pollination of Sinojackia huangmeiensis changed in ex situ populations, with complete or partial changes in herbivores, leaf herbivory rate, pollinators, pollinator visiting frequency and fruit set in the two distant ex situ populations. This work provides a unique empirical study of shifts in both antagonistic and mutualistic biotic interactions between wild and ex situ populations. We emphasized that it is essential to integrate herbivore and pollinator management in future ex situ conservation of plant species.