About

David Post is a Professor of Ecology and Evolutionary Biology at Yale University. His research focuses on aquatic ecology, testing long-standing questions about food web structure and dynamics, the influence of environmental change on community structure and ecosystem function, and the spatial linkages among ecosystems. He investigates the importance of interactions between ecology and evolution for community and ecosystem processes. Additionally, he develops and applies stable isotope techniques to address questions across ecology and evolutionary biology. The work conducted by members of the Post Lab has a direct impact on the conservation and management of aquatic resources. Although primarily working in aquatic ecosystems, his research also explores interactions and processes that link aquatic and terrestrial ecosystems.

Research topics

• Ecology
• Biology
• Fishery
• Zoology
• Geography

Selected publications

• A Gradient of Wildlife Subsidies Alters Riverine Food Web Structure

  Freshwater Biology · 2026-04-01

  article

  ABSTRACT Terrestrial subsidies play a key role in freshwater food web structure and ecosystem function. Animal‐mediated subsidies in particular provide high quality resources that shape aquatic food webs. We know little about how the magnitude of wildlife subsidies affects food web structure and stability, and how this relationship is affected by abiotic factors such as river flow. We use a wildlife subsidy gradient (hippo dung and wildebeest carcasses) in the Mara River, Kenya, to quantify the effect of subsidy magnitude on consumer use of allochthonous resources and degree of omnivory. Furthermore, we examined this relationship across seasons and flow rates to determine whether discharge affected the relationship between wildlife subsidy magnitude and allochthonous resource use. We selected three sites along the Mara River wildlife gradient with no, medium, and high wildlife input and obtained stable isotopes from dominant basal resources and consumers across invertebrate functional feeding groups and fish feeding guilds. Samples were collected across varying flows and seasons. We used Bayesian mixing models, with consumer gut contents as priors, to assess changes in the consumption and assimilation of dominant food sources by invertebrate and fish consumers across the subsidy gradient and flow rates. The Mara River food web shifted from being driven by autochthonous basal resources to being increasingly driven by allochthonous resources along the wildlife subsidy gradient. Aquatic insects and fish increased their allochthonous resource use from 27% to 52% and from 2% to 73.5%, respectively, mostly through increased consumption of hippo dung and vertebrate material during the wildebeest migration season. This diet shift led to a higher level of omnivory and a decrease in mean trophic position for invertebrates. River flow affected isotope values of consumers but not their resources at the no and medium wildlife input sites. Flow had little impact on stable isotopes at the high input site. Our results suggest that wildlife input provides an important resource for aquatic consumers and that its importance in the aquatic food web increases with its relative magnitude. Higher levels of animal‐mediated subsidies also increased consumer reliance on multiple resource pathways, suggesting higher wildlife input may increase food web stability. Abiotic factors like river flow can affect the relationship between allochthonous resource use and consumers by altering the quantity of wildlife input, but our results suggest that this is only the case when there is medium to no wildlife input. We propose that in areas with high wildlife input, subsidies are sufficiently abundant that flow has little effect on the ability of organisms to access the resource. Our results show that the magnitude of wildlife subsidies helps shape aquatic food web structure and provide the basis for the ecological theory that increasing magnitude of resource subsidies increases food web stability.

  PublisherDOI

• Monitoring a keystone species (Alosa pseudoharengus) with environmental effects: A comparison with direct capture and environmental DNA

  PLoS ONE · 2025-05-23 · 1 citations

  articleOpen accessSenior authorCorresponding

  Keystone species are important drivers of ecological processes. Their ecological importance makes them prime candidates for biological monitoring, both to preserve and restore their populations when facing decline, and to limit their spread as invasive species. To monitor species well requires cost and labor efficient methods that are capable of detecting the target species at low abundances. Traditional sampling methods, or methods of direct capture, can be labor intensive when trying to monitor large areas or species at low abundances. Another method, environmental DNA (eDNA), has emerged as a more cost and time efficient supplement to traditional monitoring methods. Environmental DNA techniques and strategies continue to be developed, but face limitations for some taxonomic groups within certain habitats. Here, we propose a novel method for monitoring keystone species: environmental effects sampling. Keystone species have large effects on their environment relative to their abundance. Measuring their environmental effects-or quantifiable changes in the biotic or abiotic environment due to organism-environment interactions-has potential as a low-effort and low-cost method for detecting keystone species. In this study, we compare the effectiveness of traditional sampling, eDNA methods, and environmental effects sampling as an alternative low cost and time efficient method for monitoring the presence and abundance of an ecologically important keystone species, the alewife, Alosa pseudoharengus, in freshwater lakes. The alewife is a zooplanktivorous fish managed as a species of conservation concern along coastal New England, USA, and an invasive or non-native species throughout the Laurentian Great Lakes watershed. We sampled lakes throughout Michigan and Connecticut from 2018-2020 and compared the three monitoring methods along four axes: alewife presence/absence, alewife abundance, financial cost, and time efficiency. Our results suggest that monitoring alewife with environmental effects is more accurate, more cost efficient, and more time efficient than purse seining and eDNA. Our environmental effects results also led to the discovery that two historically recognized alewife lakes no longer contained alewife, as confirmed by traditional sampling. However, environmental effects monitoring was only useful for determining alewife presence/absence, and was not reliable for determining alewife relative abundance. Environmental effects monitoring presents novel opportunities for efficiently and effectively monitoring keystone species such as alewife for the purpose of restoration or management.

  PublisherDOI

• The Evolution of Life History Traits and Their Thermal Plasticity in Daphnia

  Hydrobiology · 2023-01-06 · 4 citations

  articleOpen accessSenior author

  Few studies have explored the relative strength of ecogeographic versus lineage-specific effects on a global scale, particularly for poikilotherms, those organisms whose internal temperature varies with their environment. Here, we compile a global dataset of life history traits in Daphnia, at the species-and population-level, and use those data to parse the relative influences of lineage-specific effects and climate. We also compare the thermal response (plasticity) of life history traits and their dependence on climate, temperature, precipitation, and latitude. We found that the mode of evolution for life history traits varies but that the thermal response of life history traits most often follows a random walk model of evolution. We conclude that life history trait evolution in Daphnia is not strongly species-specific but is ecogeographically distinct, suggesting that life history evolution should be understood at the population level for Daphnia and possibly for other poikilotherms.

  PublisherOA PDFDOI

• Rapid population growth and high management costs have created a narrow window for control of introduced hippos in Colombia

  Scientific Reports · 2023-04-16 · 13 citations

  articleOpen access

  The introduction of hippos into the wild in Colombia has been marked by their rapid population growth and widespread dispersal on the landscape, high financial costs of management, and conflicting social perspectives on their management and fate. Here we use population projection models to investigate the effectiveness and cost of management options under consideration for controlling introduced hippos. We estimate there are 91 hippos in the middle Magdalena River basin, Colombia, and the hippo population is growing at an estimated rate of 9.6% per year. At this rate, there will be 230 hippos by 2032 and over 1,000 by 2050. Applying the population control methods currently under consideration will cost at least 1-2 million USD to sufficiently decrease hippo population growth to achieve long-term removal, and depending on the management strategy selected, there may still be hippos on the landscape for 50-100 years. Delaying management actions for a single decade will increase minimum costs by a factor of 2.5, and some methods may become infeasible. Our approach illustrates the trade-offs inherent between cost and effort in managing introduced species, as well as the importance of acting quickly, especially when dealing with species with rapid population growth rates and potential for significant ecological and social impacts.

  PublisherOA PDFDOI

• Warming overcomes dispersal-limitation to promote non-native expansion in Lake Baikal

  Journal of Great Lakes Research · 2022-08-11 · 1 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• The Evolutionary Consequences of Dams and Other Barriers for Riverine Fishes

  BioScience · 2022 · 94 citations

  • Ecology
  • Biology
  • Fishery

  Abstract Dams and other anthropogenic barriers have caused global ecological and hydrological upheaval in the blink of the geological eye. In the present article, we synthesize 307 studies in a systematic review of contemporary evolution following reduced connectivity and habitat alteration on freshwater fishes. Genetic diversity loss was more commonly observed for small populations impounded in small habitat patches for many generations behind low-passability barriers. Studies show that impoundments can cause rapid adaptive evolution in migration timing, behavior, life history, temperature tolerance, and morphology, as well as reduce phenotypic variance, which can alter adaptive potential and ecological roles. Fish passage structures can restore migratory populations but also create artificial selection pressures on body size and migration. The accelerating pace of dam removals and the paucity of data for fishes other than salmonids, other vertebrates, invertebrates, and tropical and southern hemisphere organisms highlights the urgent need for more studies on the rapid evolutionary effects of dams.

  PublisherOA PDFDOI

• World class university publication pressure across different systems

  International Journal of Research Studies in Education · 2021-07-23

  articleOpen access1st authorCorresponding

  This synthesis of a multi-year cross-national collaboration first reviews the changes facing educational researchers due to pressures to create "world class" universities. The paper then reports key findings from a comparative case study of publication patterns in South Africa, Australia, Mainland China, Hong Kong, Taiwan, Japan, and the United States (US) during the three-time slots of 1993, 2003, and 2013. The authors adopted a common research design, by selecting two departments at one public university from each system. It was found that except for the US, most faculty members in other systems were forced to change not only their publication into English but also their research topics in order to capture the interest of an international readership. In cases where English is not the predominant language of use, these trends negatively impacted scholarship in the predominant local language(s) of use. The paper concludes that the costs of using comparable measures of quality to compare "world class" universities are not borne equally across, or within, higher education systems.

  PublisherOA PDFDOI

• Animal legacies lost and found in river ecosystems

  Environmental Research Letters · 2021-10-05 · 15 citations

  articleOpen accessSenior author

  Abstract Animals can impact freshwater ecosystem structure and function in ways that persist well beyond the animal’s active presence. These legacy effects can last for months, even decades, and often increase spatial and temporal heterogeneity within a system. Herein, we review examples of structural, biogeochemical, and trophic legacies from animals in stream and river ecosystems with a focus on large vertebrates. We examine how the decline or disappearance of many native animal populations has led to the loss of their legacy effects. We also demonstrate how anthropogenically altered animal populations, such as livestock and invasive species, provide new legacy effects that may partially replace lost animal legacies. However, these new effects often have important functional differences, including stronger, more widespread and homogenizing effects. Understanding the influence of animal legacy effects is particularly important as native animal populations continue to decline and disappear from many ecosystems, because they illustrate the long-term and often unanticipated consequences of biodiversity loss. We encourage the conservation and restoration of native species to ensure that both animal populations and their legacy effects continue to support the structure and function of river ecosystems.

  PublisherOA PDFDOI

• The meta-gut: Hippo inputs lead to community coalescence of animal and environmental microbiomes

  bioRxiv (Cold Spring Harbor Laboratory) · 2021-04-08 · 3 citations

  preprintOpen accessSenior author

  Abstract All animals carry specialized microbiomes, and their gut microbiotas in particular are continuously released into the environment through excretion of waste. Here we propose the meta-gut as a novel conceptual framework that addresses the ability of the gut microbiome released from an animal to function outside the host and potentially alter ecosystem processes mediated by microbes. An example considered here is the hippopotamus (hippo) and the pools they inhabit. Hippo pool biogeochemistry and fecal and pool water microbial communities were examined through field sampling and an experiment. Sequencing using 16S RNA methods revealed that the active microbial communities in hippo pools that received high inputs of hippo feces are more similar to the hippo gut microbiome than other nearby aquatic environments. The overlap between the microbiomes of the hippo gut and the waters into which they excrete therefore constitutes a meta-gut system with potentially strong influence on the biogeochemistry of pools and downstream waters. We propose that the meta-gut may be present where other species congregate in high densities, particularly in aquatic environments. Significance Animals can have considerable impacts on biogeochemical cycles and ecosystem attributes through the consumption of resources and physical modifications of the environment. Likewise, microbial communities are well known to regulate biogeochemical cycles. This study links those two observations by showing that the gut microbiome in waste excreted by hippos can persist ex-situ in the environment and potentially alter biogeochemical cycles. This “ meta-gut ” system may be present in other ecosystems where animals congregate, and may have been more widespread in the past before many large animal populations were reduced in range and abundance.

  PublisherOA PDFDOI

• Temporal resource partitioning of wildebeest carcasses by scavengers after riverine mass mortality events

  Ecosphere · 2021-01-01 · 10 citations

  articleOpen accessSenior author

  Abstract Scavengers play an important role in nutrient recycling and disease control, and this role may be particularly critical after mass mortality events, such as those caused by epidemics, culling, or natural disasters. Current work on scavenger ecology has focused on use of single carcasses, but behaviors are likely to be different at mass mortality events, in which high resource abundance can prolong the spatial and temporal availability of carcasses. Little is currently known about how scavengers respond to large die‐offs and understanding scavenger use and succession patterns at mass mortality events has important implications for disease ecology. We used photographic time series and river‐side surveys of scavengers using carcasses to investigate scavenger use and succession on wildebeest carcasses that resulted from annual mass drownings in the Mara River, Kenya. In addition, we used telemetry data for tagged avian scavengers to assess individual use of mass drownings. Density of avian scavengers per carcass was almost two orders of magnitude lower at mass drownings than has been documented previously for single carcasses on land. Scavengers demonstrated patterns of temporal resource partitioning, with large‐bodied avian scavengers more common initially, followed by small‐bodied avian scavengers, and then by insectivorous birds and non‐avian scavengers. Avian scavengers also differed in daily activity patterns, with marabou storks more common in the morning and late afternoon and white‐backed and Rüppell’s vultures more common mid‐day. Telemetry data indicated that approximately half of tagged vultures used mass drowning events but only spent a small proportion of their time there, suggesting that competition still plays an important role in scavenger dynamics at mass mortality events and that the rewards of such abundant resources may be offset by the risk of foraging in the river. Further research on scavenger behavior during mass mortality events is needed to better understand the role of scavengers in decomposition of carcasses and disease control during these events.

  PublisherOA PDFDOI

Recent grants

• COLLABORATIVE RESEARCH: RAPID: Using river restoration to test the ecological and evolutionary effects of secondary contact

  NSF · $144k · 2013–2016

• Collaborative Research: Wildlife subsidies interact with discharge to influence ecosystem function of a large African river

  NSF · $559k · 2014–2018

• Collaborative Research: Food-Chain Length in Streams: Testing the Role of Ecosystem Size, Resource Availability and Disturbance

  NSF · $96k · 2003–2007

• Testing the Effects of Intraspecific Phenotypic Variation on Community Structure and Dynamics in Coastal Lakes: Revisiting Size Selective Predation by Alewives

  NSF · $582k · 2007–2011

• Does the magnitude of wildlife subsidies influence production, stability, and trophic cascades in a large African river?

  NSF · $841k · 2018–2023

Frequent coauthors

• Chuing Prudence Chou

  National Chung Cheng University

  36 shared

• Mayumi Ishikawa

  36 shared

• Amanda L. Subalusky

  29 shared

• Eric P. Palkovacs

  University of California, Santa Cruz

  22 shared

• Christopher L. Dutton

  19 shared

• Annika W. Walters

  17 shared

• Emma J. Rosi

  Cary Institute of Ecosystem Studies

  14 shared

• John L. Sabo

  10 shared

Education

• Ph.D.

  Cornell University

  2000

• M.S.

  University of Wisconsin–Madison

  1996

• B.S.

  University of Wisconsin–Madison

  1992