1. The role of novel ecological interactions between mammals, fungi and plants in invaded ecosystems remains unresolved, but may play a key role in the widespread successful invasion of pines and their ectomycorrhizal fungal associates, even where mammal faunas originate from different continents to trees and fungi as in New Zealand. 2. We examine the role of novel mammal associations in dispersal of ectomycorrhizal fungal inoculum of North American pines (Pinus contorta, Pseudotsuga menziesii), and native beech trees (Lophozonia menziesii) using faecal analyses, video monitoring and a bioassay experiment. 3. Both European red deer (Cervus elaphus) and Australian brushtail possum (Trichosurus vulpecula) pellets contained spores and DNA from a range of native and non-native ectomycorrhizal fungi. 4. Faecal pellets from both animals resulted in ectomycorrhizal infection of pine seedlings with fungal genera Rhizopogon and Suillus, but not with native fungi or the invasive fungus Amanita muscaria, despite video and DNA evidence of consumption of these fungi. 5. Native L. menziesii seedlings never developed any ectomycorrhizal infection from faecal pellet inoculation. 6. Synthesis. Our results show that introduced mammals from Australia and Europe facilitate the co-invasion of invasive North American trees and Northern Hemisphere fungi in New Zealand, while we find no evidence that introduced mammals benefit native trees or fungi. This novel tripartite ‘invasional meltdown’, comprising taxa from three kingdoms and three continents, highlights unforeseen consequences of global biotic homogenization.
Movie_S1
Red deer (Cervus elaphus) consuming Amanita muscaria mushroom in Pinus contorta plantation at Helicopter Hill, Craigieburn, South Island, New Zealand.
Movie_S2
Red deer (Cervus elaphus) consuming Amanita muscaria mushroom in Pinus contorta plantation at Helicopter Hill, Craigieburn, South Island, New Zealand.
Movie_S3
Brushtail possums (Trichosurus vulpecula) consuming Amanita muscaria mushroom in Pinus contorta plantation at Helicopter Hill, Craigieburn, South Island, New Zealand.
Movie_S4
Brushtail possum (Trichosurus vulpecula) appearing to exhibit aversion behaviour towards Amanita muscaria mushroom in Pinus contorta plantation at Helicopter Hill, Craigieburn, South Island, New Zealand.
Movie_S5
Brushtail possum (Trichosurus vulpecula) consuming Cortinarius sp. mushrooms in mixed beech (Nothofagaceae)–Eucalyptus forest at Helicopter Hill, Craigieburn, South Island, New Zealand.
SI_text
QIIME scripts used to analyse fungal ITS sequences generated from mammal faecal pellets from Craigieburn, South Island, New Zealand.
Figure_S1
Percentage occurrence of ectomycorrhizal fungal taxa in red deer (Cervus elaphus) and brushtail possum (Trichosurus vulpecula) faecal pellet samples (n = 14 and 16 respectively) from Craigieburn, South Island, New Zealand, as detected using 454 sequencing.
Figure_S2
Pollen assemblages from faecal pellets of brushtail possums (Trichosurus vulpecula) (n = 17) and red deer (Cervus elaphus) (n = 14) collected from Craigieburn, South Island, New Zealand, between 27 March and 19 May 2012. Circles represent pollen types present at <2.5%.
Figure_S3
Examples of ectomycorrhizal fungal spores from brushtail possum (Trichosurus vulpecula) and red deer (Cervus elaphus) faecal pellets, Craigieburn, South Island, New Zealand. (a) abundant fungal spores on a palynology slide; (b) Octaviania spore; (c) cf. Laccaria spores; (d) Rhizopogon spore?
Figure_S4
Virtual gel showing RFLP patterns produced by BSrR1 and HpyCH41V restriction enzymes on ITS1f-ITS4 DNA fragments amplified from seedling root tips infected with ectomycorrhizal fungi from faecal pellets in our study.
Figure_S5
Principal components analysis of faecal-pellet pollen assemblages. Circles represent brushtail possum (Trichosurus vulpecula) pellets and triangles represent red deer (Cervus elaphus) pellets. Filled shapes represent pellets that infected seedlings with each respective fungal taxon, and open shapes represent those that did not. Dominant pollen vectors are shown as grey arrows.
Table_S1
Occurrence frequency of fungal taxa identified from 454 sequencing of red deer (Cervus elaphus) and brushtail possum (Trichosurus vulpecula) faecal pellets from Craigieburn, South Island, New Zealand
Table_S2
Identity of RFLP patterns (see Fig. S4) observed for ectomycorrhizal fungi on seedling root tips infected from faecal pellets in our study. Identities were determined by DNA sequencing of representative samples for each pattern