In landscapes that are fragmented and disturbed by anthropogenic activities, it is likely that late successional plant species will be the highest conservation priorities due to limited availability of undisturbed habitat. These late successional plant species may also be more dependent on soil communities to maintain their fitness, and consequently, the restoration of soil communities has the potential to improve the outcomes of ecological restoration. We tested these hypotheses in the tallgrass prairie, ecosystems that are highly endangered by both habitat destruction and fragmentation and by human disturbance of remaining habitat. First, for 55 prairie species, we measured eight traits that are expected to vary with an r vs. K-selected life history strategy (i.e. early or late successional). We then compared these traits to coefficients of conservatism. These values rank a plant species’ dependence on undisturbed natural areas and are often used to set conservation priorities. We also used these traits to identify how plant responses to mycorrhizal fungi and plant-soil feedbacks vary with plant species’ life-history strategy.
Results/Conclusions
We found that six of the eight traits we measured were correlated with a species coefficient of conservatism (CC). Plants with low CCs grew faster and taller and were more likely to flower. High CC species had higher root:shoot ratios, thicker leaves, and leaves survived longer. Overall, the first principle component of these trait data was aligned with plant successional status and was strongly correlated with a species’ coefficient of conservatism (r2 = 0.44). These results indicate that the plants most likely to thrive in environments with frequent anthropogenic disturbance are those with ruderal life history traits, including rapid growth rates and early investment in reproduction. Conversely, conservation priority species, including those restricted only to undisturbed natural areas, are more likely to be late-successional plants. Additionally, the first PC of traits was correlated with plant species’ responsiveness to mycorrhizal fungi (r2 = 0.41) and with plant-soil feedbacks experienced by these plant species (r2 = 0.24). These correlations show that early successional plants experience relatively strong negative plant-soil feedbacks, and that late successional plants are more dependent on mutualisms with mycorrhizal fungi. Overall, these results indicate that conservation of prairie plant diversity will require protecting nature preserves from anthropogenic disturbance to protect the most conservation dependent species. Further, restoration efforts will more effectively re-establish these late-successional plant species if they restore native microbial mutualisms.