Jeremy Long

Department of Biology
Professor, Biology
Faculty Sponsor, MEBSA

Office/Lab: SDSU Main Campus, Physical Science 142A/142
Phone: 619-594-3598 (office)
Email: jlong@sdsu.edu

Long Lab

I am an ecologist interested in the relationships between plants and their herbivores, and how these interactions shape communities and ecosystems.  Specifically, I study the importance of chemical signals to these dynamic interactions using a combination of field and laboratory experiments.  My unique approach utilizes skills in behavioral assays of consumers (planktonic, benthic, and terrestrial), bioassay-guided fractionation of secondary metabolites of algae and invertebrates and mesocosm and field experiments.
Current and Past Projects

1. Induced responses of algae to herbivores

Numerous species of plants and prey induce morphological, chemical, or behavioral defenses in response to cues associated with consumers. Despite the importance of induced responses to community structure, we know relatively little about the ecology of these interactions in phytoplankton and seaweeds. Recent work in my lab demonstrated that 1) seaweeds may indirectly influence competitive interactions between herbivore species via inducible responses and 2) some phytoplankton responses are surprisingly herbivore-specific. We are also testing the importance of inducible responses to the timing and size of phytoplankton blooms.

2. Geographic variation in plant-herbivore interactions

Although we have a good sense of the diverse taxa exhibiting inducible defenses, our knowledge of how inducible defenses within a species vary spatially is surprisingly poor. We are currently examining geographic variation in inducible defenses in three different systems and scales; salt marsh plants along the east coast, seaweeds across 1000s of km, and seaweeds across 10-100s of km.

3. Human-induced alteration of intertidal communities

Rocky intertidal communities are highly valued because of their visibility and accessibility to people and their ecological importance. However, people can negatively impact these communities both knowingly and unknowingly. Using field caging experiments, we are addressing the following two questions: 1) Does trampling influence barnacle communities and if so, how do these influences vary with ontogeny and site? and 2) Does predator removal indirectly alter plant production and diversity in southern California salt marshes? Additionally, we have started studying the impact of people on harvested snails in San Diego.

4. Long-term ecological monitoring

Rocky intertidal communities provide critical habitat to marine and terrestrial species and these habitats are threatened by a variety of stressors including climate change, invasive species, pollution, and human trampling. Unfortunately, we currently lack baseline data on the health and natural variability of these communities in some regions and, thus, are unable to predict the occurrence and consequences of such environmental changes. We are developing a long-term, low-cost protocol that will detail procedures for monitoring this habitat in New England. We are especially interested in broad-scale comparisons (e.g. Atlantic vs. Pacific shores).

5. Learned aversions in marine consumers

Learning provides an ecological response to changing prey availability and defenses by allowing consumers to add novel foods to their diets while reducing the risk of consuming noxious foods. Unfortunately, how consumers learn to accept or avoid new foods is better understood for terrestrial than for marine consumers where studies of diet learning have been infrequent. We are conducting comparative studies of learning among consumers to improve our understanding of learned aversions and the prey that exploit these behaviors in their consumers.

Ric DeSantiago (Ph.D.)

B.S. Environmental Sciences, San Diego State University (2018)

Research Interests: Marine community ecology, invasive species, intertidal ecology, environmental pollution, STEM education outreach

Dissertation topic: Herbivore community assemblage response to invasive seaweeds in black abalone habitats

Email: rdesantiago@sdsu.edu

Anthony Truong (M.S.)

B.S. Aquatic Biology, University of California Santa Barbara

Research Interests: Climate impacts on intertidal communities and interactions between macroalgae and invertebrates

Thesis topic: Climate change effects on the ability of crustose coralline algae to recruit invertebrate larvae

Email: atruong3397@sdsu.edu

Jan Walker (Ph.D.)

B.S Environmental Science, University of Virginia (2015)

Research Interests: Marine community ecology, salt marsh ecology, plant-plant interactions, mutualisms, restoration

Dissertation topic: Understanding the effects of habitat modifiers on plant community composition in California salt marshes

Email: janwalker@ucdavis.edu

Rinehart, S.A. and J.D. Long (in revision). Alternative resource identity and omnivore numerical responses impact prey populations: a meta-analysis.

Haggerty, M.B., T.W. Anderson, and J.D. Long (2018). Fish predators reduce kelp frond loss via a trait-mediated trophic cascade. Ecology 99: 1574-1583.

Jones, E. and J.D. Long (2018). Geographic variation in the sensitivity of an herbivore-induced seaweed defense. Ecology 99: 1748-1758.

Rinehart, S.A. and J.D. Long (2018). Habitat use is linked to resource-specific performance of an ecologically important marsh predator. Ecosphere 9: e02273.

Jones, E. and J.D. Long (2017). The relative strength of an herbivore-induced seaweed defense varies with herbivore species. Marine Ecology Progress Series 581: 33-44.

Rinehart, S.A., S.C. Schroeter, and J.D. Long (2017). Density mediated indirect effects from active predators and narrow habitat domain prey. Ecology 10: 2653-2661.

Demko, A.M., C.D. Amsler, M.E. Hay, J.D. Long, J.B. McClintock, V.J. Paul, and E.E. Sotka (2017). Declines in plant palatability from polar to tropical latitudes depend on herbivore and plant identity. Ecology 98: 2312-2321.

Miller, L.P. and J.D. Long (2015). A tide prediction and tide height control system for laboratory mesocosms. PeerJ 3: e1442.

​Warneke, A.M. and J.D. Long (2015). Copper contamination impairs herbivore initiation of seaweed inducible defenses and decreases their effectiveness. PLOS ONE 10: e0135395.

Kwan, C.K., E. Sanford, and J.D. Long (2015). Copper pollution increases the relative importance of predation risk in an aquatic food web. PLOS ONE 10: e0133329.