About

Dr. Tyler Kartzinel is an internationally recognized molecular ecologist and Associate Professor at Brown University, where he leads the Genomic Opportunities Lab (GenOps). He is a Fellow of the Institute at Brown for Environment and Society. Kartzinel is renowned for pioneering research at the intersection of ecology, genomics, and data science. His work explores critical species interactions such as predator-prey, plant-herbivore, and host-parasite dynamics, and their relevance to global environmental and biomedical challenges. He is celebrated for advancing DNA metabarcoding and genome-enabled approaches in conservation biology. Kartzinel has been honored with an NSF CAREER award, an NSF Early Career Fellowship, and election as an Early Career Fellow by the Ecological Society of America for outstanding contributions at the interface of ecology and molecular biology, and for pioneering use of DNA metabarcoding to elucidate the structure of complex terrestrial food webs. His research has been featured by top journals and media outlets including Nature, PNAS, National Geographic, BBC World, PBS NOVA, The New York Times, and NPR. Several of his papers have been ranked as "Red Hot" and "Highly Cited" by Web of Science for the attention they garnered in the field.

Research topics

• Ecology
• Biology
• Geology
• Oceanography
• Climatology

Selected publications

• Impacts of large herbivores on savanna plant communities: Towards predictive models of herbivore selectivity and plant response

  DRYAD · 2026-03-23

  datasetOpen access

  Large herbivores are among the most ecologically influential and extinction-prone animals. Megaherbivores in particular radically alter vegetation. Few studies have tried to predict the impacts of herbivores—or their loss—on plant species composition and community structure. First principles suggest that preferred plants should be suppressed by herbivores and released by herbivore removal, but this prediction may be misleading if responses are strongly contingent on plant traits and plant–plant interactions. We sought to predict responses of plant species to size-selective herbivore exclusion in an African savanna, using data on herbivore diets (from DNA metabarcoding) and plant functional traits. Our analysis had three stages. First, we identified plant traits that predicted selectivity (use relative to availability) by the dominant herbivore species excluded by different experimental treatments: megaherbivores (elephant, giraffe; ≥ 1000 kg), mesoherbivores (buffalo, zebra, impala; 40–600 kg), and dik-dik (5 kg). Several plant traits predicted selectivity across multiple herbivore species, but species’ diets were predicted by unique suites of traits. Second, we tested whether herbivore selectivity alone predicted plant responses. Elephant selectivity uniquely predicted plant responses in exclosures relative to unfenced control plots (R2 = 0.24–0.30); taxa strongly favored by elephants were ninefold more abundant inside exclosures. However, herbivore selection failed to predict differences between fenced exclusion treatments, suggesting that bottom-up effects of plant competition intensify relative to consumptive effects as large-bodied herbivores are removed. Third, including plant traits as covariates along with elephant selectivity modestly improved predictability (R2 = 0.27–0.50). Despite various sources of uncertainty and imprecision inherent to our approach, including inability to distinguish selection for different plant parts/stages, we show that elephant foraging decisions are a primary determinant of plant community dynamics. Moreover, our findings indicate that models based on readily attainable data can substantially predict plant community responses to the extirpation or reintroduction of megafauna. Future work can refine our approach by incorporating additional traits associated with plant tolerance and competition, along with more granular and mechanistic measurements of herbivore preferences and biomass consumption, to predict even more accurately how large herbivore population declines and extinctions will impact plant communities.

  PublisherDOI

• Experimental defaunation alters foraging behavior of a small antelope (Guenther’s Dik-dik, <i>Madoqua guentheri</i>  ) in Kenya

  Journal of Mammalogy · 2026-04-15

  articleSenior author

  Abstract African savannas are experiencing an array of human-induced changes, including reductions and extirpations of large mammalian herbivores. The outcomes of these changes will be at least partially dependent on the functional responses of species that persist, including changes to plant-herbivore interaction networks. However, experimental tests of how ecological context, season, and competition jointly regulate foraging behaviors of large mammals are sparse. Therefore, we combined dietary DNA metabarcoding and a long-term herbivore-exclusion experiment in semi-arid Kenyan savanna to understand how a small browsing antelope (Guenther’s Dik-dik, Madoqua guentheri, ∼5 kg) responds to the absence of larger herbivores across seasons (e.g., wet vs dry) and sites (e.g., mesic vs xeric). We hypothesized that: (i) dik-dik diets would differ from those of co-occurring large browsers due to size-based differences in forage selection and accessibility; (ii) exclusion of larger herbivores would increase dik-dik activity and enable them to select high-quality browse, consistent with competitive release; and (iii) this selective foraging by dik-dik would suppress the growth and recruitment of their preferred woody food species. Consistent with our hypotheses, dik-dik diets differed significantly from co-occurring—but much larger—mixed-feeders, including the African Savanna Elephant (Loxodonta africana) and Impala (Aepyceros melampus). Dik-dik foraged selectively according to plant nutritional properties, especially protein content, and they avoided long-spined Acacia species, particularly during dry seasons and at the xeric site. In the absence of larger herbivores, dik-dik activity increased &amp;gt;2-fold, and they increased selectivity for the most nutritious, least-defended Acacia species. Shifts in selectivity due to competitive release were strongest under resource-scarce conditions, including dry seasons and xeric environments, amplifying local impacts of large-herbivore losses on savanna plant communities. Finally, in the absence of larger browsers, dik-dik suppressed the growth of their preferred species (Acacia mellifera), but only at the xeric site. Together, these results provide strong evidence that dik-dik exhibit flexible foraging behavior in response to larger herbivores, especially in resource-scarce conditions. If large herbivores are extirpated, subsequent diet shifts by dik-dik may suppress long-term plant diversity in this savanna.

  PublisherDOI

• Dataset and R scripts for: Climate-driven resource availability drives medium- and broad-scale temporal changes in owl–prey interactions over 24 years in a semi-arid ecosystem

  Figshare · 2025-04-15

  datasetOpen access

  R scripts used for statistical analyses, along with their associated databases and input matrices

  PublisherDOI

• Levels and partitioning of genetic variation of northeastern populations of diamondback terrapin ( <i>Malaclemys terrapin</i> )

  Journal of Heredity · 2025-09-13

  articleSenior author

  The diamondback terrapin (Malaclemys terrapin) is a mid-sized turtle that serves as a keystone predator in salt marsh ecosystems of eastern North America. The terrapin has historically faced population declines due to habitat loss and overharvesting, which has resulted in its listing under multiple jurisdictions across the northern part of its range. To characterize levels and partitioning of terrapin genetic variation throughout the northeast region, we used restriction site-associated DNA sequencing (RADseq). We analyzed genetic variation among 116 individuals sampled across 18 sites. Within-population genetic diversity was relatively low (He = 0.080 to 0.122), and we observed a strong negative correlation between diversity and latitude. Furthermore, levels of genetic differentiation were moderate (pairwise FST = 0.00 to 0.19), with the mean pairwise FST of each population exhibiting a strong positive correlation with latitude. Together, these results are consistent with a model of serial colonization from a Pleistocene refugium in the mid-Atlantic. Spatial genetic variation was best explained by a landscape model that considered migration to be limited to coastal habitats, where northern range-edge populations maintained comparatively low genetic diversity and were more genetically distinct than populations to the south-consistent with their greater geographic isolation. Admixture analyses revealed weak genetic clustering, with the distribution of genetic clusters reflecting the combined historical effects of isolation-by-distance and human-mediated translocations. Regional efforts to restore terrapin habitat or reintroduce captive individuals should consider patterns of historic gene flow, cognizant of the relatively distinct and isolated populations at the northeastern range edge.

  PublisherDOI

• The apportionment of dietary diversity in wildlife

  Proceedings of the National Academy of Sciences · 2025-07-14 · 3 citations

  articleSenior authorCorresponding

  Evaluating species’ roles in food webs is critical for advancing ecological theories on competition, coexistence, and biodiversity but is complicated by pronounced dietary variability within species and overlap across species. We combined dietary DNA metabarcoding, GPS tracking, and a machine-learning algorithm to cluster and compare dietary profiles within and among five migratory large-herbivore species from Yellowstone National Park. Interspecific niche partitioning was weak, but statistically significant (PERMANOVA: pseudo- F 4,498 = 14.7, R 2 = 0.11, P ≤ 0.001), such that some diet profiles from different species were as similar as those from within one species. Instead of affirming species’ identity as a primary determinant of diet composition, we found three statistically different clusters of diet profiles—one concentrated on graminoids and forbs, another on forbs and deciduous shrubs, and a third on gymnosperms—each including samples from all herbivore species. Clusters did not reflect traditional diet classification schemes such as the grazer-browser continuum that is often used to distinguish species by percent grass consumption or use of grassland habitat in African savannas. Instead, clusters in Yellowstone reflected seasonal dietary variation within species that often equaled or exceeded niche differences between species, contributing to our growing understanding of why environmental variability may favor generalist foraging strategies at temperate latitudes, whereas specialized grazer and browser guilds appear to predominate in tropical savannas. Data-driven strategies that untangle complex trophic networks without relying on a priori groupings can offer new insights into wildlife diets, with potential applications in resource management and environmental monitoring.

  PublisherDOI

• Host specificity of gastrointestinal parasites in free-ranging sloths from Costa Rica

  PeerJ · 2025-05-08

  articleOpen accessSenior author

  The diversity and host specificity of gastrointestinal parasites infecting free-ranging sloths is poorly known. We compared gastrointestinal parasites of two sloth species from Costa Rica—three-fingered sloths ( Bradypus variegatus ) and two-fingered sloths ( Choloepus hoffmanni )—for the first time in both a primary forest and an urban habitat. We asked whether host-parasite interactions were predominantly structured by host identity, the habitats in which hosts occurred, or both. Coproparasitology revealed protozoa and nematode eggs from both host species, but cestode eggs were recorded only in C. hoffmanni . We found eight parasitic morphotypes in 38 samples, which matches the total number of these parasites described in sloths over the past 100 years. We found no significant difference in overall parasite richness between sloth species or habitats, but the parasite richness of C. hoffmanni was 2-fold greater in the primary forest vs . urban habitat. As no parasite sharing was observed between sloth species, we found strong and significant differences in parasite composition between host species regardless of habitat. In B. variegatus , we observed eggs of four nematode taxa (Spirocercidae, Subuluroidea, Spirurida, Ascaridida) and cysts of Eimeriidae (Apicomplexa). By contrast, in C. hoffmanni , we observed cestodes (Anoplocephalidae), a different nematode from the family Spirocercidae, and also different cysts of Eimeriidae (Apicomplexa). Many rare taxa were recorded only in samples from the primary forest, and these did not match any sloth parasites that had been previously described in the literature, suggesting that at least some could be undescribed species. Together, these results highlight the paucity of comparative parasitology involving tropical wildlife, the importance of characterizing host-parasite transmission networks, and the potential relevance of intermediate hosts that may be relevant to sloth health.

  PublisherOA PDFDOI

• Distinct morphological drivers of jumping and maneuvering performance in gerbils

  Journal of Experimental Biology · 2025-01-10 · 3 citations

  articleOpen accessSenior author

  Theoretically, animals with longer hindlimbs are better jumpers, while those with shorter hindlimbs are better maneuverers. Yet, experimental evidence of this relationship in mammals is lacking. We compared jump force and maneuverability in a lab population of Mongolian gerbils (Meriones unguiculatus). We hypothesized that gerbils with long legs (ankle to knee) and thighs (knee to hip) would produce the greatest jump forces, while gerbils with short legs and thighs would be able to run most rapidly around turns. Consistent with these hypotheses, gerbils with longer legs produced greater jump forces after accounting for sex and body mass: a 1 mm greater leg length provided 1 body weight unit greater jump force on average. Furthermore, gerbils with shorter thighs were more maneuverable: a 1 mm greater thigh length reduced turn speed by 5%. Rather than a trade-off, however, there was no significant correlation between jump force and turn speed. There was also no correlation between jump force and total hindlimb length, and a weak positive correlation between corner-turning speed and total hindlimb length. These experiments revealed how distinct hindlimb segments contributed in different ways to each performance measure: legs to jumping and thighs to maneuvering. Understanding how variations in limb morphology contribute to overall gerbil locomotor performance may have important impacts on fitness in natural habitats.

  PublisherOA PDFDOI

• Diet-microbiome covariation across three giraffe species in a close-contact zone

  Global Ecology and Conservation · 2025-02-05 · 2 citations

  articleOpen accessSenior authorCorresponding

  The biodiverse group of ruminant mammals are entirely dependent on their gut microbiota to extract energy and nutrients from their foods, making these symbionts vital to survival. Because variation in wildlife diets can select for distinct communities of gut bacteria, different foraging choices can have both nutritional effects and other microbially-mediated effects on animal well-being. Despite the proliferation of studies focusing on host-microbiome interactions in recent decades, few prior studies have quantified the level and extent of diet-microbiome linkages in wildlife. Therefore, we used DNA metabarcoding to compare the diets and gut microbiomes of giraffes, the world’s largest ruminant. We focused on three giraffe species—reticulated, northern, and Masai—that occur along a near-contact zone in equatorial Kenya. We found large differences in both the composition and diversity of diets and microbiomes within and among populations. However, contrary to expectations, we found very little evidence for links between the composition of individual diets and their corresponding microbiomes. Instead, geographic proximity strongly predicted diet similarity whereas host-species identity strongly predicted microbiome composition. The lack of diet-microbiome linkages across these giraffe populations—coupled with the evidence that species differed strongly in diet and microbiome compositions—highlights the possibility that their history of ecological and evolutionary divergence has generated unique, species-specific gut microbiomes. Moreover, striking levels of diet variation were revealed among neighboring populations of giraffe from the same species, and thus baseline knowledge of their resource-use diversity could support ongoing efforts to geographically tailor management strategies aimed at conserving local food staples under environmental change. • Kenya’s giraffes are endangered (reticulated, Masai) or critically endangered (Nubian). • Diets and microbiomes of giraffe species were compared using DNA metabarcoding. • Surprisingly, we found no consistent link between diet and microbiome composition or diversity. • Geography strongly predicted diets while species identity predicted microbiomes. • Protecting a diversity of staple food plants could help sustain access to nutritious forage.

  PublisherDOI

• Repository

  Figshare · 2025-04-15

  datasetOpen access

  R scripts used for statistical analyses, along with their associated databases and input matrices

  PublisherDOI

• Global Availability of Plant <scp>DNA</scp> Barcodes as Genomic Resources to Support Basic and Policy‐Relevant Biodiversity Research

  Molecular Ecology · 2025-02-28 · 11 citations

  reviewOpen access1st authorCorresponding

  Genetic technologies such as DNA barcoding make it easier and less expensive to monitor biodiversity and its associated ecosystem services, particularly in biodiversity hotspots where traditional assessments are challenging. Successful use of these data-driven technologies, however, requires access to appropriate reference data. We reviewed the >373,584 reference plant DNA barcodes in public repositories and found that they cumulatively cover a remarkable quarter of the ~435,000 extant land plant species (Embryophyta). Nevertheless, coverage gaps in tropical biodiversity hotspots reflect well-documented biases in biodiversity science - most reference specimens originated in the Global North. Currently, at least 17% of plant families lack any reference barcode data whatsoever, affecting tropical and temperate regions alike. Investigators often emphasise the importance of marker choice and the need to ensure protocols are technically capable of detecting and identifying a broad range of taxa. Yet persistent geographic and taxonomic gaps in the reference datasets show that these protocols rely upon risk undermining all downstream applications of the strategy, ranging from basic biodiversity monitoring to policy-relevant objectives - such as the forensic authentication of materials in illegal trade. Future networks of investigators could work strategically to improve data coverage, which will be essential in global efforts to conserve biodiversity while advancing more fair and equitable access to benefits arising from genetic resources.

  PublisherOA PDFDOI

Recent grants

• CAREER: Experimental tests of competition and facilitation among migratory large herbivores from Yellowstone National Park

  NSF · $921k · 2021–2026

• COLLABORATIVE RESEARCH: Testing predictions of the core-satellite and resource-breadth hypotheses in small mammal communities: field tests of a macroecological pattern

  NSF · $150k · 2020–2023

• Collaborative Research: LTREB: Experimental determination of trophic dynamics and energy flows in a semiarid habitat in Chile

  NSF · $244k · 2020–2025

Frequent coauthors

• Robert M. Pringle

  Princeton University

  66 shared

• Jacob R. Goheen

  Wyoming Department of Education

  45 shared

• Todd M. Palmer

  University of Cape Town

  45 shared

• Johan Pansu

  Université Claude Bernard Lyon 1

  43 shared

• Courtney G. Reed

  University of California, Santa Barbara

  39 shared

• Duncan M. Kimuyu

  Karatina University

  34 shared

• Leo M. Khasoha

  University of Wyoming

  30 shared

• Brian A. Gill

  University of Arizona

  28 shared

Labs

• Kartzinel LabPI

  CONSERVATION & MOLECULAR ECOLOGY

Awards & honors

• 2025 Catalyst Research Awardees