Fleshing out facilitation – reframing interaction networks beyond top-down versus bottom-up

• Published in: The New phytologist Vol. 211; no. 3; pp. 803 - 808
• Main Author: Watson, David M.
• Format: Journal Article
• Language: English
• Published: England New Phytologist Trust 01.08.2016; Wiley Subscription Services, Inc
• Subjects: aboveground–belowground connections; Animals; Ecosystem; facilitation cascade; Forests; hemiparasite; mistletoe; Mistletoe - physiology; nutrient dynamics; plant–animal interactions; Tansley insights; Tropical Climate; hemiparasite; nutrient dynamics; facilitation cascade; mistletoe; plant-animal interactions; aboveground-belowground connections
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.14052

Rather than direct plant–plant interactions, research on the community-scale influence of mistletoes reveals hitherto unappreciated roles of animals in mediating facilitation. Lacking roots and reliant upon animal vectors, mistletoes represent model systems with which to understand mechanisms underlying interaction networks. In addition to direct effects on nutrient dynamics via enriched litter-fall, mistletoes are visited by pollinators, seed dispersers and natural enemies, complementing increased heterogeneity in nutrient returns reallocated from infected hosts with increased external inputs. These amplified bottom-up effects are coupled with top-down influences of insectivores attracted to infected hosts and stands by increased availability of favoured prey. Simultaneously influencing nutrient dynamics and plant–plant interactions from below andabove, visiting animals help explain variation in the context dependenceof facilitation.