Print PageResearch to predict climate change impacts in rangeland ecosystems has emphasized effects on dominant grass and shrub species and implications for grazing management. Less attention has been given to the forb component of rangelands. Managed ecosystems are, by definition, coupled natural-human systems. Successful strategies to sustain and restore managed ecosystems therefore must account not only for ecosystem components but also for human factors. To understand how summer temperature increase might affect native and non-native rangeland forbs in the interior western U.S. we combined a field experiment with study of range manager perceptions of forbs and climate change. Native forbs Sphaeralcea munroana, Crepis acuminata, Linum lewisii, Penstemon palmeri and Oenothera pallida and non-natives Erodium cicutarium and Lactuca serriola were subjected over two seasons to two treatments in a field setting: experimental warming in open-top chambers and a control. We measured effects on emergence rate, timing of emergence and senescence, flowering, and several fitness parameters. Semi-structured telephone interviews of 22 range managers from six states provided qualitative data about their knowledge of and attention to forbs, and perceptions of local climate and land changes. The latter were compared to local long-term climate data.
Results/Conclusions
Experimental results showed that growth of the natives S. munroana, L. lewisii and P. palmeri was not reduced by temperature increases of up to 5˚C, suggesting these species may be resilient to predicted changes in summer climate. Fitness was reduced for C. acuminata and O. pallida. Temperature did not affect E. cicutarium fitness but warming did lead to earlier germination, while warming decreased all fitness parameters for L. serriola. Results suggest that selection of forbs for restoration projects should account for differential species responses to warming, in addition to current selection criteria. Forb selection is also influenced by human factors such as seed cost and managers’ beliefs about conditions affecting restoration success. About half of interviewees did not perceive changes in local summer temperatures or precipitation, although trend data showed changes in 80% of their locales. Managers with more years in their current jobs gave less definite but more accurate climate answers. Those perceiving no change tended to base answers on recent weather conditions while those noting changes relied more on long-term patterns. Forbs typically weren't viewed as an important indicator of ecosystem health or resilience. Overall our results suggest a need for better information among managers about forbs, local climate changes, and implications for rangeland restoration.
