Taylor, S., & Kumar, L. (2016). Will climate change impact the potential distribution of a native vine (Merremia peltata) which is behaving invasively in the Pacific region? Ecology and Evolution, 6(3), 742-754. https://doi.org/10.1002/ece3.1915

Summary

Merremia peltata (M. peltata) is a woody vine found throughout warm, tropical regions of the Pacific Islands and its native/non-native status across the region is uncertain. In parts of the Pacific, it is considered a troublesome weed that can smother trees and reduce native biodiversity, and the Australia and Hawaiʻi Weed Risk Assessments classify it as “high risk.” In some locations, however, this species can play an important role in rainforest regeneration and it is known to support biodiversity when growing in the forest canopy. How this species distribution will be impacted by climate change is currently unknown.

To determine the current distribution as well as potential future distributions under climate change, Taylor and Kumar used species distribution modeling based on experimental observations of M. peltata growth response to temperature, soil moisture, current distribution, and seasonal phenology. They used occurrence data to assess the fit of the model to current distributions and considered two end-of-century global climate model projections for future distribution (a warmer/much drier projection and a much warmer/less dry projection).

Results

M. peltata is expected to both expand and contract its range in response to modeled climate shifts over time. Generally, range expansion is expected on Fiji, Hawaii, New Caledonia, and Vanuatu, and contractions are expected in Papua New Guinea and the Solomon Islands. Areas currently not suitable are expected to become suitable under a future climate. In addition, substantial range contraction under a future climate is expected in Papua New Guinea. Finally, the projected changes to future ranges were consistent between climate models for Fiji, Hawaiʻi, New Caledonia, and Vanuatu, but differed for the other countries and appeared to be strongly related to rainfall.

Management Considerations

• Consider strengthening quarantine regulations and enforcement as well as surveillance around ports and airports in order to prevent the introduction of species like Merremia peltata, especially in areas where climatic suitability is expected to expand the species range in the future.
• Where M. peltata is non-native, consider potential future climate change distributions when prioritizing areas for intervention, such as eradication or containment.
• Where M. peltata is native, consider potential future climate change distributions to inform conservation strategies; modeling may identify areas of potential range contraction or refuges where protection could be prioritized.
• Consider monitoring for impacts to agriculture, native plant communities, or culturally important plant species; factors such as disturbance (clearing, typhoons) or growth form (ground or tree vine) may influence its impact on the community.

Take Home Points

• Species distribution modelling of current and potential future ranges can play an important role in invasive plant management as ranges and habitat suitability shift with changing climatic conditions.
• Increased access to species occurrence records, as well as climate-informed distribution modelling is needed to support informed decision-making.
• Integrated assessments that investigate large-scale changes to ecosystems due to multiple interacting factors are needed. How species shift in the future will depend not just on the direct effects of climate change, but also on changes in land use and disturbance, new invasive species arrivals, nutrient pollution, and species interactions.