Peer Review #1 of "Hemiparasitic plants increase alpine plant richness and evenness but reduce arbuscular mycorrhizal fungal colonization in dominant plant species (v0.1)" [peer_review]

2018 unpublished
Hemiparasitic plants increase plant biodiversity by reducing the abundance of dominant plant species, allowing for the establishment of subordinate species. Hemiparasites reduce host resources by directly removing nutrients from hosts, competing for light and space, and may indirectly reduce host resources by disrupting plant associations with symbiotic root fungi, like arbuscular mycorrhizal fungi and dark-septate endophytes. Here we explored how a generalist hemiparasite,
more » ... astilleja,influences plant richness, evenness, community composition, and mycorrhizal colonization patterns across a ~1000m elevational gradient in the North American Rocky Mountains. We hypothesized that the presence of Castillejawould be associated with increased plant richness and evenness, shaping plant community composition, and would reduce mycorrhizal colonization within dominant plant taxa. However, the magnitude of the effects would be contingent upon climate contexts i.e.elevation. Overall, we found that the presence of Castillejawas associated with an 11% increase in plant richness and a 5% increase in plant evenness, regardless of elevation. However, we found that the presence ofCastillejainfluenced plant composition at only two of the five sites and at the remaining three of five sites, plot pairing was the only predictor that influenced composition. Additionally, we found that the presence of Castillejareduced mycorrhizal fungal colonization within dominant plant species by ~20%, regardless of elevation. Taken together, our results suggest that hemiparasites regulate plant diversity, evenness, and interactions with mycorrhizal fungi independent of abiotic and biotic contexts occurring at the site, although overall effect on community composition is likely driven by site-level factors. Manuscript to be reviewed 20 Abstract (249 words) 21 Hemiparasitic plants increase plant biodiversity by reducing the abundance of dominant 22 plant species, allowing for the establishment of subordinate species. Hemiparasites reduce host 23 resources by directly removing nutrients from hosts, competing for light and space, and may 24 indirectly reduce host resources by disrupting plant associations with symbiotic root fungi, like 25 arbuscular mycorrhizal fungi and dark-septate endophytes. Here we explored how a generalist 26 hemiparasite, Castilleja, influences plant richness, evenness, community composition, and 27 mycorrhizal colonization patterns across a ~1000m elevational gradient in the North American 28 Rocky Mountains. We hypothesized that the presence of Castilleja would be associated with 29 increased plant richness and evenness, shaping plant community composition, and would reduce 30 mycorrhizal colonization within dominant plant taxa. However, the magnitude of the effects 31 would be contingent upon climate contexts i.e. elevation. Overall, we found that the presence of 32 Castilleja was associated with an 11% increase in plant richness and a 5% increase in plant 33 evenness, regardless of elevation. However, we found that the presence of Castilleja influenced 34 plant composition at only two of the five sites and at the remaining three of five sites, plot 35 pairing was the only predictor that influenced composition. Additionally, we found that the 36 presence of Castilleja reduced mycorrhizal fungal colonization within dominant plant species by 37~20%, regardless of elevation. Taken together, our results suggest that hemiparasites regulate 38 plant diversity, evenness, and interactions with mycorrhizal fungi independent of abiotic and 39 biotic contexts occurring at the site, although overall effect on community composition is likely 40 driven by site-level factors.
doi:10.7287/peerj.5682v0.1/reviews/1 fatcat:pmdbj5kbjrhslhr3xrkbjydddq