From the ground up: Building predictions for how climate change will affect belowground mutualisms, floral traits, and bee behavior

Plant functional traits predict heterogeneous distributional shifts in response to climate change

“…Ultimately, the high incidence of range-shifting species within our study has the potential to result in novel biotic interactions, including both the gain in antagonistic interactions (novel competitors, pathogens and herbivores) as well as the loss of mutualists (soil microbes and pollinators), which could either facilitate or hinder species' distributional changes (Alexander et al, 2015;Hagedorn et al, 2019;Keeler et al, 2021). Moreover, as dryland ecosystems have a disproportionate role in the global carbon budget (Ahlström et al, 2015), the replacement towards more acquisitive leaf traits in response to climate change should alter nutrient cycling and carbon sequestration (Buzzard et al, 2019).…”

“…We found a clear pattern of species' distributional responses to contemporary climate change being mediated by their functional traits, where species possessing more conservative resource‐use traits shifted upwards and declined in abundance, while species with more resource‐acquisitive traits shifted downward and increased in abundance. Ultimately, the high incidence of range‐shifting species within our study has the potential to result in novel biotic interactions, including both the gain in antagonistic interactions (novel competitors, pathogens and herbivores) as well as the loss of mutualists (soil microbes and pollinators), which could either facilitate or hinder species' distributional changes (Alexander et al, 2015; Hagedorn et al, 2019; Keeler et al, 2021). Moreover, as dryland ecosystems have a disproportionate role in the global carbon budget (Ahlström et al, 2015), the replacement towards more acquisitive leaf traits in response to climate change should alter nutrient cycling and carbon sequestration (Buzzard et al, 2019).…”

Legume germination is delayed in dry soils and in sterile soils devoid of microbial mutualists: Species‐specific implications for upward range expansions

“…The loss of this segment of DNA ultimately causes a complete breakdown of the mutualism, only likely after numerous short‐term losses of the mutualism. A climate change‐induced breakdown in the mutualism between legumes and rhizobia will have significant effects on legume germination, phenology, and N‐acquisition, which could affect higher‐order mutualists, such as pollinators (Keeler et al, 2021 ), and plant community structure (Suttle et al, 2007 ). Just as floral traits such as nectar quality can be directly related to soil nutrient availability (Burkle & Irwin, 2009 ; Mevi‐Schutz & Erhardt, 2005 ), short‐ or long‐term loss of the interaction between plants and soil microbial species due to mutualism loss or breakdown will indirectly affect floral traits by altering host plant nutrient acquisition (Ballhorn et al, 2013 ; Gwata et al, 2003 ; Megueni et al, 2006 ; Namvar & Sharifi, 2011 ), which could cascade to affect pollinator behavior and legume reproductive success (Keeler et al, 2021 ).…”

“…A climate change‐induced breakdown in the mutualism between legumes and rhizobia will have significant effects on legume germination, phenology, and N‐acquisition, which could affect higher‐order mutualists, such as pollinators (Keeler et al, 2021 ), and plant community structure (Suttle et al, 2007 ). Just as floral traits such as nectar quality can be directly related to soil nutrient availability (Burkle & Irwin, 2009 ; Mevi‐Schutz & Erhardt, 2005 ), short‐ or long‐term loss of the interaction between plants and soil microbial species due to mutualism loss or breakdown will indirectly affect floral traits by altering host plant nutrient acquisition (Ballhorn et al, 2013 ; Gwata et al, 2003 ; Megueni et al, 2006 ; Namvar & Sharifi, 2011 ), which could cascade to affect pollinator behavior and legume reproductive success (Keeler et al, 2021 ). The long‐term fitness consequences of this particular mutualism loss are generally unknown (Berg et al, 2010 ; Kiers et al, 2010 ), although slower growth and lower quality floral rewards in these pollinator‐dependent, pollen‐limited plants (Xingwen, 2021 ) may further decrease reproductive success and thus recruitment in a warming, drying climate.…”

“…The absence or reduced abundance of microbial mutualists beyond the current range of a population could impair plant fitness and hinder leading range expansion (Hu et al, 2022 ; Lankau & Keymer, 2016 ; Miransari, 2010 ; Peay et al, 2010 ; Sedlacek et al, 2014 ; Wu & Ying‐Ning, 2017 ). Non‐co‐dispersed, horizontally transmitted symbionts, including legumes, rhizobia, and some other PGPR, may be at high risk of becoming spatially mismatched as they may track climate differently (Keeler et al, 2021 ). Legumes that interact with specialized mutualists may be less likely to find a compatible partner in novel habitats and thus may fail to establish (Simonsen et al, 2017 ), while legumes that have been successful in expanding into novel ranges without a historical partner may have benefitted from their ability to relax their partner choice mechanisms and establish interactions with generalist mutualists (Harrison et al, 2017 ; Younginger & Friesen, 2019 ).…”