Bio


I am an advanced 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 research 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


2023-24 Courses


All Publications


  • Scale dependence of coral reef oases and their environmental correlates. Ecological applications : a publication of the Ecological Society of America Elahi, R., Edmunds, P. J., Gates, R. D., Kuffner, I. B., Barnes, B. B., Chollett, I., Courtney, T. A., Guest, J. R., Lenz, E. A., Toth, L. T., Viehman, T. S., Williams, I. D. 2022: e2651

    Abstract

    Identifying relatively intact areas within ecosystems, and determining the conditions favoring their existence, is necessary for effective management in the context of widespread environmental degradation. In this study, we used 3,766 surveys of randomly selected sites in the United States and U.S. Territories to identify the correlates of sites categorized as 'oases' (defined as sites with relatively high total coral cover). We used occupancy models to evaluate the influence of ten environmental predictors on the probability that an area (21.2 km2 cell) would harbor coral oases defined at four spatial extents: cross-basin, basin, region, and sub-region. Across all four spatial extents, oases were more likely to occur in habitats with high light attenuation. The influence of the other environmental predictors on the probability of oasis occurrence were less consistent and varied with the scale of observation. Oases were most likely in areas of low human population density, but this effect was evident only at the cross-basin and sub-regional extents. At the regional and sub-regional extents oases were more likely where sea-surface temperature was more variable, whereas at the larger spatial extents the opposite was true. By identifying the correlates of oasis occurrence, the model can inform the prioritization of reef areas for management. Areas with biophysical conditions that confer corals with physiological resilience, as well as limited human impacts, likely support coral reef oases across spatial extents. Our approach is widely applicable to the development of conservation strategies to protect biodiversity and ecosystems in an era of magnified human disturbance.

    View details for DOI 10.1002/eap.2651

    View details for PubMedID 35538862

  • 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

  • Rapid Range Expansion of a Marine Ectotherm Reveals the Demographic and Ecological Consequences of Short-Term Variability in Seawater Temperature and Dissolved Oxygen AMERICAN NATURALIST Burford, B. P., Wild, L. A., Schwarz, R., Chenoweth, E. M., Sreenivasan, A., Elahi, R., Carey, N., Hoving, H. T., Straley, J. M., Denny, M. W. 2022

    View details for DOI 10.1086/718575

    View details for Web of Science ID 000766932200001

  • 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

  • Mapping human pressures on biodiversity across the planet uncovers anthropogenic threat complexes PEOPLE AND NATURE Bowler, D. E., Bjorkman, A. D., Dornelas, M., Myers-Smith, I. H., Navarro, L. M., Niamir, A., Supp, S. R., Waldock, C., Winter, M., Vellend, M., Blowes, S. A., Bohning-Gaese, K., Bruelheide, H., Elahi, R., Antao, L. H., Hines, J., Isbell, F., Jones, H. P., Magurran, A. E., Cabral, J., Bates, A. E. 2020; 2 (2): 380-394

    View details for DOI 10.1002/pan3.10071

    View details for Web of Science ID 000647695600011

  • 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 DOI 10.1016/j.cub.2015.05.030

    View details for PubMedID 26166784