Bio


I am a lecturer at Stanford University’s Hopkins Marine Station, where I teach courses in kelp forest ecology, statistics, and scientific computing. In general, I study drivers of spatial and temporal change in marine ecosystems. Ongoing and recent projects include:
-examining the consequences of fisheries closures on fisher behavior
-understanding why some coral reefs fare better than their neighbors
-biodiversity and body size change, particularly in the context of recent human impacts

Academic Appointments


2020-21 Courses


All Publications


  • Historical comparisons of body size are sensitive to data availability and ecological context. Ecology Elahi, R., Miller, L. P., Litvin, S. Y. 2020

    Abstract

    Historical comparisons of body size often lack pertinent details, including information on the sampling protocol and relevant ecological covariates that influence body size. Moreover, historical estimates of body size that rely on museum specimens may be biased towards larger size classes due to collector preferences, and thus size thresholds have been used to focus attention on maximum body size. We tested the consequences of sampling design, ecological covariates, and size thresholds on inferences of body size change using field-contextualized historical records, rather than museum specimens. In 2014-2015, we revisited historical (1947-1963) size-frequency distributions of three gastropods (Tegula funebralis, Lottia digitalis / L. austrodigitalis, Littorina keenae) in the context of population density and tidal height. In general, gastropods declined in size. However, our inferences regarding body size decline were tempered when the variation between sampling units was taken into consideration, resulting in greater uncertainty around the estimate of proportional change in body size. Gastropod size was correlated with population density and tidal height, and these relationships varied over time. Finally, the magnitude and direction of body size change varied with the amount of data available for analysis, demonstrating that the use of size thresholds can lead to incomplete conclusions.

    View details for DOI 10.1002/ecy.3101

    View details for PubMedID 32455494

  • Disturbances drive changes in coral community assemblages and coral calcification capacity ECOSPHERE Courtney, T. A., Barnes, B. B., Chollett, I., Elahi, R., Gross, K., Guest, J. R., Kuffner, I. B., Lenz, E. A., Nelson, H. R., Rogers, C. S., Toth, L. T., Andersson, A. J. 2020; 11 (4)

    View details for DOI 10.1002/ecs2.3066

    View details for Web of Science ID 000536583400010

  • A framework for identifying and characterising coral reef "oases" against a backdrop of degradation JOURNAL OF APPLIED ECOLOGY Guest, J. R., Edmunds, P. J., Gates, R. D., Kuffner, I. B., Andersson, A. J., Barnes, B. B., Chollett, I., Courtney, T. A., Elahi, R., Gross, K., Lenz, E. A., Mitarai, S., Mumby, P. J., Nelson, H. R., Parker, B. A., Putnam, H. M., Rogers, C. S., Toth, L. T. 2018; 55 (6): 2865–75
  • Leveraging vessel traffic data and a temporary fishing closure to inform marine management FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Elahi, R., Ferretti, F., Bastari, A., Cerrano, C., Colloca, F., Kowalik, J., Ruckelshaus, M., Struck, A., Micheli, F. 2018; 16 (8): 440–45

    View details for DOI 10.1002/fee.1936

    View details for Web of Science ID 000446011400004

  • The Resilience of Marine Ecosystems to Climatic Disturbances BIOSCIENCE O'Leary, J. K., Micheli, F., Airoldi, L., Boch, C., De Leo, G., Elahi, R., Ferretti, F., Graham, N. A., Litvin, S. Y., Low, N. H., Lummis, S., Nickols, K. J., Wong, J. 2017; 67 (3): 208-220
  • Ocean warming and the demography of declines in coral body size MARINE ECOLOGY PROGRESS SERIES Elahi, R., Sebens, K. P., De Leo, G. A. 2016; 560: 147-158

    View details for DOI 10.3354/meps11931

    View details for Web of Science ID 000390104900010

  • Recent Trends in Local-Scale Marine Biodiversity Reflect Community Structure and Human Impacts CURRENT BIOLOGY Elahi, R., O'Connor, M. I., Byrnes, J. E., Dunic, J., Eriksson, B. K., Hensel, M. J., Kearns, P. J. 2015; 25 (14): 1938-1943

    Abstract

    The modern biodiversity crisis reflects global extinctions and local introductions. Human activities have dramatically altered rates and scales of processes that regulate biodiversity at local scales [1-7]. Reconciling the threat of global biodiversity loss [2, 4, 6-9] with recent evidence of stability at fine spatial scales [10,11] is a major challenge and requires a nuanced approach to biodiversity change that integrates ecological understanding. With a new dataset of 471 diversity time series spanning from 1962 to 2015 from marine coastal ecosystems, we tested (1) whether biodiversity changed at local scales in recent decades, and (2) whether we can ignore ecological context (e.g., proximate human impacts, trophic level, spatial scale) and still make informative inferences regarding local change. We detected a predominant signal of increasing species richness in coastal systems since 1962 in our dataset, though net species loss was associated with localized effects of anthropogenic impacts. Our geographically extensive dataset is unlikely to be a random sample of marine coastal habitats; impacted sites (3% of our time series) were underrepresented relative to their global presence. These local-scale patterns do not contradict the prospect of accelerating global extinctions [2,4,6-9] but are consistent with local species loss in areas with direct human impacts and increases in diversity due to invasions and range expansions in lower impact areas. Attempts to detect and understand local biodiversity trends are incomplete without information on local human activities and ecological context.

    View details for DOI 10.1016/j.cub.2015.05.030

    View details for Web of Science ID 000358465600035

  • Field stations as sentinels of change FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Micheli, F., Carlton, J., Pearse, J., Selgrath, J., Elahi, R., Watanabe, J., Mach, M., McDevitt-Irwin, J., Pearse, V., Burnett, N., Baxter, C. 2020; 18 (6): 320–21

    View details for DOI 10.1002/fee.2231

    View details for Web of Science ID 000554674700004

  • Species richness change across spatial scales OIKOS Chase, J. M., McGill, B. J., Thompson, P. L., Antao, L. H., Bates, A. E., Blowes, S. A., Dornelas, M., Gonzalez, A., Magurran, A. E., Supp, S. R., Winter, M., Bjorkman, A. D., Bruelheide, H., Byrnes, J. K., Cabral, J., Elahi, R., Gomez, C., Guzman, H. M., Isbell, F., Myers-Smith, I. H., Jones, H. P., Hines, J., Vellend, M., Waldock, C., O'Connor, M. 2019; 128 (8): 1079–91

    View details for DOI 10.1111/oik.05968

    View details for Web of Science ID 000478622500002

  • Recent Trends in Local-Scale Marine Biodiversity Reflect Community Structure and Human Impacts. Current biology : CB Elahi, R., O'Connor, M. I., Byrnes, J. E., Dunic, J., Eriksson, B. K., Hensel, M. J., Kearns, P. J. 2015; 25 (14): 1938–43

    Abstract

    The modern biodiversity crisis reflects global extinctions and local introductions. Human activities have dramatically altered rates and scales of processes that regulate biodiversity at local scales [1-7]. Reconciling the threat of global biodiversity loss [2, 4, 6-9] with recent evidence of stability at fine spatial scales [10,11] is a major challenge and requires a nuanced approach to biodiversity change that integrates ecological understanding. With a new dataset of 471 diversity time series spanning from 1962 to 2015 from marine coastal ecosystems, we tested (1) whether biodiversity changed at local scales in recent decades, and (2) whether we can ignore ecological context (e.g., proximate human impacts, trophic level, spatial scale) and still make informative inferences regarding local change. We detected a predominant signal of increasing species richness in coastal systems since 1962 in our dataset, though net species loss was associated with localized effects of anthropogenic impacts. Our geographically extensive dataset is unlikely to be a random sample of marine coastal habitats; impacted sites (3% of our time series) were underrepresented relative to their global presence. These local-scale patterns do not contradict the prospect of accelerating global extinctions [2,4,6-9] but are consistent with local species loss in areas with direct human impacts and increases in diversity due to invasions and range expansions in lower impact areas. Attempts to detect and understand local biodiversity trends are incomplete without information on local human activities and ecological context.

    View details for PubMedID 26166784