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11 results on '"Bork, E.W."'

2. Extreme drought impacts have been underestimated in grasslands and shrublands globally

Author

Smith, M.D., Wilkins, K.D., Holdrege, M.C., Wilfahrt, P., Collins, S.L., Knapp, A.K., Sala, O.E., Dukes, J.S., Phillips, R.P., Yahdjian, L., Gherardi, L.A., Ohlert, T., Beier, C., Fraser, L.H., Jentsch, A., Loik, M.E., Maestre, F.T., Power, S.A., Yu, Q., Felton, A.J., Munson, S.M., Luo, Y., Abdoli, H., Abedi, M., Alados, C.L., Alberti, J., Alon, M., An, H., Anacker, B., Anderson, M., Auge, Harald, Bachle, S., Bahalkeh, K., Bahn, M., Batbaatar, A., Bauerle, T., Beard, K.H., Behn, K., Beil, I., Biancari, L., Blindow, I., Bondaruk, V.F., Borer, E.T., Bork, E.W., Bruschetti, C.M., Byrne, K.M., Cahill jr., J.F., Calvo, D.A., Carbognani, M., Cardoni, A., Carlyle, C.N., Castillo-Garcia, M., Chang, S.X., Chieppa, J., Cianciaruso, M.V., Cohen, O., Cordeiro, A.L., Cusack, D.F., Dahlke, S., Daleo, P., D'Antonio, C.M., Dietterich, L.H., Doherty, T.S., Dubbert, M., Ebeling, A., Eisenhauer, N., Fischer, F.M., Forte, T.G.W., Gebauer, T., Gozalo, B., Greenville, A.C., Guidoni-Martins, K.G., Hannusch, H.J., Haugum, S.V., Hautier, Y., Hefting, M., Henry, H.A.L., Hoss, D., Ingrisch, J., Iribarne, O., Isbell, F., Johnson, Y., Jordan, S., Kelly, E.F., Kimmel, K., Kreyling, J., Kröel-Dulay, G., Kröpfl, A., Kübert, A., Kulmatiski, A., Lamb, E.G., Steenberg Larsen, K., Larson, J., Lawson, J., Leder, C.V., Linstädter, A., Liu, J., Liu, S., Lodge, A., Longo, G., Smith, M.D., Wilkins, K.D., Holdrege, M.C., Wilfahrt, P., Collins, S.L., Knapp, A.K., Sala, O.E., Dukes, J.S., Phillips, R.P., Yahdjian, L., Gherardi, L.A., Ohlert, T., Beier, C., Fraser, L.H., Jentsch, A., Loik, M.E., Maestre, F.T., Power, S.A., Yu, Q., Felton, A.J., Munson, S.M., Luo, Y., Abdoli, H., Abedi, M., Alados, C.L., Alberti, J., Alon, M., An, H., Anacker, B., Anderson, M., Auge, Harald, Bachle, S., Bahalkeh, K., Bahn, M., Batbaatar, A., Bauerle, T., Beard, K.H., Behn, K., Beil, I., Biancari, L., Blindow, I., Bondaruk, V.F., Borer, E.T., Bork, E.W., Bruschetti, C.M., Byrne, K.M., Cahill jr., J.F., Calvo, D.A., Carbognani, M., Cardoni, A., Carlyle, C.N., Castillo-Garcia, M., Chang, S.X., Chieppa, J., Cianciaruso, M.V., Cohen, O., Cordeiro, A.L., Cusack, D.F., Dahlke, S., Daleo, P., D'Antonio, C.M., Dietterich, L.H., Doherty, T.S., Dubbert, M., Ebeling, A., Eisenhauer, N., Fischer, F.M., Forte, T.G.W., Gebauer, T., Gozalo, B., Greenville, A.C., Guidoni-Martins, K.G., Hannusch, H.J., Haugum, S.V., Hautier, Y., Hefting, M., Henry, H.A.L., Hoss, D., Ingrisch, J., Iribarne, O., Isbell, F., Johnson, Y., Jordan, S., Kelly, E.F., Kimmel, K., Kreyling, J., Kröel-Dulay, G., Kröpfl, A., Kübert, A., Kulmatiski, A., Lamb, E.G., Steenberg Larsen, K., Larson, J., Lawson, J., Leder, C.V., Linstädter, A., Liu, J., Liu, S., Lodge, A., and Longo, G.

Abstract

Climate change is increasing the frequency and severity of short-term (~1 y) drought events—the most common duration of drought—globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in the severity and duration of drought studied, and differences among ecosystems in vegetation, edaphic and climatic attributes that can mediate drought impacts. To overcome these problems and better identify the factors that modulate drought responses, we used a coordinated distributed experiment to quantify the impact of short-term drought on grassland and shrubland ecosystems. With a standardized approach, we imposed ~a single year of drought at 100 sites on six continents. Here we show that loss of a foundational ecosystem function—aboveground net primary production (ANPP)—was 60% greater at sites that experienced statistically extreme drought (1-in-100-y event) vs. those sites where drought was nominal (historically more common) in magnitude (35% vs. 21%, respectively). This reduction in a key carbon cycle process with a single year of extreme drought greatly exceeds previously reported losses for grasslands and shrublands. Our global experiment also revealed high variability in drought response but that relative reductions in ANPP were greater in drier ecosystems and those with fewer plant species. Overall, our results demonstrate with unprecedented rigor that the global impacts of projected increases in drought severity have been significantly underestimated and that drier and less diverse sites are likely to be most vulnerable to extreme drought.

Published
2024

4. Relating changes in duff moisture to the Canadian Forest Fire Weather Index System in Populus tremuloides stands in Elk Island National Park

Author

Otway, S.G., Bork, E.W., Anderson, K.R., and Alexander, M.E.

Subjects
Alberta -- Environmental aspects, Forest fire research -- Usage -- Environmental aspects, Populus tremuloides -- Properties -- Usage -- Environmental aspects, Environmental indexes -- Usage -- Environmental aspects, Earth sciences, Usage, Properties, Environmental aspects
Abstract

Abstract: The manner in which trembling aspen (Populus tremuloides Michx.) forest duff moisture changes during the growing season was investigated in Elk Island National Park, Alberta, Canada. A calibration-validation procedure [...]

Published
2007

7. Global change effects on plant communities are magnified by time and the number of global change factors imposed

Author

Komatsu, K.J., Avolio, M.L., Lemoine, N.P., Isbell, F., Grman, E., Houseman, G.R., Koerner, S.E., Johnson, D.S., Wilcox, K.R., Alatalo, J.M., Anderson, J.P., Aerts, R., Baer, S.G., Baldwin, A.H., Bates, J., Beierkuhnlein, C., Belote, R.T., Blair, J., Bloor, J.M.G., Bohlen, P.J., Bork, E.W., Boughton, E.H., Bowman, W.D., Britton, A.J., Cahill jr., J.F., Chaneton, E., Chiariello, N.R., Cheng, J., Collins, S.L., Cornelissen, J.H.C., Du, G., Eskelinen, Anu Maria, Firn, J., Foster, B., Gough, L., Gross, K., Hallett, L.M., Han, X., Harmens, H., Hovenden, M.J., Jagerbrand, A., Jentsch, A., Kern, C., Klanderud, K., Knapp, A.K., Kreyling, J., Li, W., Luo, Y., McCulley, R.L., McLaren, J.R., Megonigal, J.P., Morgan, J.W., Onipchenko, V., Pennings, S.C., Prevéy, J.S., Price, J.N., Reich, P.B., Robinson, C.H., Russell, F.L., Sala, O.E., Seabloom, E.W., Smith, M.D., Soudzilovskaia, N.A., Souza, L., Suding, K., Suttle, K.B., Svejcar, T., Tilman, D., Tognetti, P., Turkington, R., White, S., Xu, Z., Yahdjian, L., Yu, Q., Zhang, P., Zhang, Y., Komatsu, K.J., Avolio, M.L., Lemoine, N.P., Isbell, F., Grman, E., Houseman, G.R., Koerner, S.E., Johnson, D.S., Wilcox, K.R., Alatalo, J.M., Anderson, J.P., Aerts, R., Baer, S.G., Baldwin, A.H., Bates, J., Beierkuhnlein, C., Belote, R.T., Blair, J., Bloor, J.M.G., Bohlen, P.J., Bork, E.W., Boughton, E.H., Bowman, W.D., Britton, A.J., Cahill jr., J.F., Chaneton, E., Chiariello, N.R., Cheng, J., Collins, S.L., Cornelissen, J.H.C., Du, G., Eskelinen, Anu Maria, Firn, J., Foster, B., Gough, L., Gross, K., Hallett, L.M., Han, X., Harmens, H., Hovenden, M.J., Jagerbrand, A., Jentsch, A., Kern, C., Klanderud, K., Knapp, A.K., Kreyling, J., Li, W., Luo, Y., McCulley, R.L., McLaren, J.R., Megonigal, J.P., Morgan, J.W., Onipchenko, V., Pennings, S.C., Prevéy, J.S., Price, J.N., Reich, P.B., Robinson, C.H., Russell, F.L., Sala, O.E., Seabloom, E.W., Smith, M.D., Soudzilovskaia, N.A., Souza, L., Suding, K., Suttle, K.B., Svejcar, T., Tilman, D., Tognetti, P., Turkington, R., White, S., Xu, Z., Yahdjian, L., Yu, Q., Zhang, P., and Zhang, Y.

Abstract

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.

Published
2019

8. Asynchrony among local communities stabilises ecosystem function of metacommunities

Author

Wilcox, K.R., Tredennick, A.T., Koerner, S.E., Grman, E., Hallett, L.M., Avolio, M.L., La Pierre, K.J., Houseman, G.R., Isbell, F., Johnson, D.S., Alatalo, J.M., Baldwin, A.H., Bork, E.W., Boughton, E.H., Bowman, W.D., Britton, A.J., Cahill jr., J.F., Collins, S.L., Du, G., Eskelinen, Anu Maria, Gough, L., Jentsch, A., Kern, C., Klanderud, K., Knapp, A.K., Kreyling, J., Luo, Y., McLaren, J.R., Megonigal, P., Onipchenko, V., Prevéy, J., Price, J.N., Robinson, C.H., Sala, O.E., Smith, M.D., Soudzilovskaia, N.A., Souza, L., Tilman, D., White, S.R., Xu, Z., Yahdjian, L., Yu, Q., Zhang, P., Zhang, Y., Wilcox, K.R., Tredennick, A.T., Koerner, S.E., Grman, E., Hallett, L.M., Avolio, M.L., La Pierre, K.J., Houseman, G.R., Isbell, F., Johnson, D.S., Alatalo, J.M., Baldwin, A.H., Bork, E.W., Boughton, E.H., Bowman, W.D., Britton, A.J., Cahill jr., J.F., Collins, S.L., Du, G., Eskelinen, Anu Maria, Gough, L., Jentsch, A., Kern, C., Klanderud, K., Knapp, A.K., Kreyling, J., Luo, Y., McLaren, J.R., Megonigal, P., Onipchenko, V., Prevéy, J., Price, J.N., Robinson, C.H., Sala, O.E., Smith, M.D., Soudzilovskaia, N.A., Souza, L., Tilman, D., White, S.R., Xu, Z., Yahdjian, L., Yu, Q., Zhang, P., and Zhang, Y.

Abstract

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species’ populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales.

Published
2017

11. Simulation and quantification of pasture condition and animal performance on boreal grasslands in Alberta

Author

Donkor, N.T., Hudson, R.J., and Bork, E.W.

Subjects
*BIOTIC communities, *ANIMAL psychology, *FORAGE plants, *GRAZING
Abstract

Abstract: We developed a computer model (PASTURE) to simulate both condition of pastures grazed by farmed wildlife and animal performance as dual measures of system performance. For representative habitat types (e.g., aspen forest and open grasslands), the model simulates herbage growth, maturation and senescence, habitat and diet selection, and nutrient intake of several wild ruminant species. The model generated seasonal patterns of pasture productivity and animal behavior expected for Bromus-Poa pastures in aspen boreal ecosystems. Model calibration was conducted using data collected from studies conducted within the aspen boreal ecosystems at the Ministik Research Station in 1997 and 1998, and Elk Island National Park and the University of Alberta greenhouse in 1999 and parameters adjusted until the predicted and observed results were visibly close. Evaluation of the model was conducted using statistical criteria of calculating average error, root mean square, root mean square error, coefficient of residual mass and modeling efficiency and comparing these statistics against optimal values. Statistical tests indicated a good fit between predicted and observed values for cumulative phytomass, herbage use and animal performance. [Copyright &y& Elsevier]

Published
2007
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