Browsing by Author "Germino, Matthew J."

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Effects of experimentally reduced snowpack and passive warming on montane meadow plant phenology and floral resources.
(2017-03) Sherwood, Jill A.; Debinski, Diane M.; Caragea, P. C.; Germino, Matthew J.
Climate change can have a broad range of effects on ecosystems and organisms, and early responses may include shifts in vegetation phenology and productivity that may not coincide with the energetics and forage timing of higher trophic levels. We evaluated phenology, annual height growth, and foliar frost responses of forbs to a factorial experiment of snow removal (SR) and warming in a high-elevation meadow over two years in the Rocky Mountains, United States. Species included arrowleaf balsamroot (Balsamorhiza sagittata, early-season emergence and flowering) and buckwheat (Eriogonum umbellatum, semi-woody and late-season flowering), key forbs for pollinator and nectar-using animal communities that are widely distributed and locally abundant in western North America. Snow removal exerted stronger effects than did warming, and advanced phenology differently for each species. Specifically, SR advanced green-up by a few days for B. sagittata to >2 wk in E. umbellatum, and led to 5- to 11-d advances in flowering of B. sagittata in one year and advances in bud break in 3 of 4 species/yr combinations. Snow removal increased height of E. umbellatum appreciably (~5 cm added to ~22.8 cm in control), but led to substantial increases in frost damage to flowers of B. sagittata. Whereas warming had no effects on E. umbellatum, it increased heights of B. sagittata by >6 cm (compared to 30.7 cm in control plots) and moreover led to appreciable reductions in frost damage to flowers. These data suggest that timing of snowmelt, which is highly variable from year to year but is advancing in recent decades, has a greater impact on these critical phenological, growth, and floral survival traits and floral/nectar resources than warming per se, although warming mitigated early effects of SR on frost kill of flowers. Given the short growing season of these species, the shifts could cause uncoupling in nectar availability and timing of foraging.
Montane Meadow Change during Drought Varies with Background Hydrologic Regime and Plant Functional Group
(2010-01) Debinski, Diane M.; Wickham, Hadley A.; Kindscher, Kelly; Caruthers, Jennet C.; Germino, Matthew J.
Climate change models for many ecosystems predict more extreme climatic events in the future, including exacerbated drought conditions. Here we assess the effects of drought by quantifying temporal variation in community composition of a complex montane meadow landscape characterized by a hydrological gradient. The meadows occur in two regions of the Greater Yellowstone Ecosystem (Gallatin and Teton) and were classified into six categories (M1–M6, designating hydric to xeric) based upon Satellite pour l’Observation de la Terre (SPOT) satellite imagery. Both regions have similar plant communities, but patch sizes of meadows are much smaller in the Gallatin region. We measured changes in the percent cover of bare ground and plants by species and functional groups during five years between 1997 and 2007. We hypothesized that drought effects would not be manifested evenly across the hydrological gradient, but rather would be observed as hotspots of change in some areas and minimally evident in others. We also expected varying responses by plant functional groups (forbs vs. woody plants). Forbs, which typically use water from relatively shallow soils compared to woody plants, were expected to decrease in cover in mesic meadows, but increase in hydric meadows. Woody plants, such as Artemisia, were expected to increase, especially in mesic meadows. We identified several important trends in our meadow plant communities during this period of drought: (1) bare ground increased significantly in xeric meadows of both regions (Gallatin M6 and Teton M5) and in mesic (M3) meadows of the Teton, (2) forbs decreased significantly in the mesic and xeric meadows in both regions, (3) forbs increased in hydric (M1) meadows of the Gallatin region, and (4) woody species showed increases in M2 and M5 meadows of the Teton region and in M3 meadows of the Gallatin region. The woody response was dominated by changes in Artemisia spp. and Chrysothamnus viscidiflorus. Thus, our results supported our expectations that community change was not uniform across the landscape, but instead could be predicted based upon functional group responses to the spatial and temporal patterns of water availability, which are largely a function of plant water use and the hydrological gradient.
Testing the Effects of Simulated Climate Change Effects Using Open Sided Warming Chambers
(2010-01) Sherwood, Jill A.; Debinski, Diane M.; Germino, Matthew J.
Regional models of global climate change for the northern Rocky Mountains predict warmer temperatures, and some of the main implications of these changes at a local level involve decreased snowpack, earlier snowmelt, and decreased soil moisture during the growing season. In order to mimic the anticipated effects of climate change, and test the responses from a soil microclimate and plant physiology perspective, open-sided warming chambers and snow removal treatments were applied to 2.44 X 2.44 m plots in a sagebrush steppe meadow within Grand Teton National Park, WY. Four treatments included: (1) control, (2) reduced snowpack, (3) increased temperature, and (4) reduced snowpack with increased temperature. Snow was removed using shovels in early May, and chambers were placed at the same time. The chambers were left on the plots through mid-October. Soil moisture and temperature were measured and recorded at 5 cm, and 25 cm depths using dataloggers set up at the time of snow removal and chamber placement. In addition, surface temperature was measured under each plot and within the study area. Plant physiological data on four plant species, including leaf temperature at dawn and mid-afternoon and water potential, were collected for all of the plots in July. Data are being analyzed to determine whether differences existed between the plots for soil moisture, soil and air temperature, and the plant physiological traits measured.
Warming temperatures affect meadow‐wide nectar resources, with implications for plant–pollinator communities
(Wiley, 2022-07) McCombs, Audrey L.; Debinski, Diane M.; Reinhardt, Keith; Germino, Matthew J.; Caragea, Petrutza
Nectar production may be a point of sensitivity that can help link primary and secondary trophic responses to climate shifts, and is therefore important to our understanding of ecosystem responses. We evaluated the nectar response of two widespread native forbs, Balsamorhiza sagittata and Eriogonum umbellatum, to experimental warming in a high-elevation sagebrush meadow in the Teton Range, WY, USA, over two years, 2015 and 2016. Warming treatments reduced the occurrence of nighttime freezing and nectar volume but increased sugar concentration in nectar in both species in both years. Warming effects were also evident in a consistent increase in the number of flowers produced by B. sagittata. Our research suggests that warming associated with climate change has the potential to induce shifts in the nectar-feeding community by changing nectar characteristics such as volume and sugar concentration to which nectar feeders are adapted.
Warming temperatures affect meadow‐wide nectar resources, with implications for plant–pollinator communities
(Wiley, 2022-07) McCombs, Audrey L.; Debinski, Diane M.; Reinhardt, Keith; Germino, Matthew J.; Caragea, Petrutza
Nectar production may be a point of sensitivity that can help link primary and secondary trophic responses to climate shifts, and is therefore important to our understanding of ecosystem responses. We evaluated the nectar response of two widespread native forbs, Balsamorhiza sagittata and Eriogonum umbellatum, to experimental warming in a high-elevation sagebrush meadow in the Teton Range, WY, USA, over two years, 2015 and 2016. Warming treatments reduced the occurrence of nighttime freezing and nectar volume but increased sugar concentration in nectar in both species in both years. Warming effects were also evident in a consistent increase in the number of flowers produced by B. sagittata. Our research suggests that warming associated with climate change has the potential to induce shifts in the nectar-feeding community by changing nectar characteristics such as volume and sugar concentration to which nectar feeders are adapted.
Weed-Suppressive Bacteria Fail to Control Bromus tectorum Under Field Conditions
(Elsevier BV, 2020-11) Reinhart, Kurt O.; Carlson, Chris H.; Feris, Kevin P.; Germino, Matthew J.; Jandreau, Clancy J.; Lazarus, Brynne E.; Mangold, Jane; Pellatz, Dave W.; Ramsey, Philip; Rinella, Matthew J.; Valliant, Morgan
The exotic winter annual grass Bromus tectorum L. (downy brome or cheatgrass) infests millions of hectares of western rangelands. Weed-suppressive bacteria (ACK55 and D7 strains of Pseudomonas fluorescens Migula 1895) have been shown to reduce B. tectorum populations in eastern Washington. Unfortunately, outside of Washington, little is known about the efficacy of these or other weed-suppressive bacteria. We used Petri-plate and plant-soil bioassays to test effects of ACK55 and D7 on B. tectorum from Montana and Wyoming. We also tested effects of ACK55 on B. tectorum at six field sites in Montana and one in Wyoming. P. fluorescens reduced B. tectorum germination and root and shoot lengths in Petri-plates but had no effect on plants during growth chamber plant-soil bioassays or field experiments. Bromus arvensis L. (field brome or Japanese brome), a species similar to B. tectorum, was prevalent at two of our sites, and ACK55 was ineffective against B. arvensis as well. Our findings contribute to a growing body of evidence that the ACK55 and D7 strains of P. fluorescens are not reliable tools for controlling B. tectorum in the Northern Great Plains, Central Rocky Mountains, and elsewhere.