Complex eco-evolutionary responses of a foundational coastal marsh plant to global change.

Predicting the fate of coastal marshes requires understanding how plants respond to rapid environmental change. Environmental change can elicit shifts in trait variation attributable to phenotypic plasticity and act as selective agents to shift trait means, resulting in rapid evolution. Comparably, less is known about the potential for responses to reflect the evolution of trait plasticity. Here, we assessed the relative magnitude of eco-evolutionary responses to interacting global change factors using a multifactorial experiment. We exposed replicates of 32 Schoenoplectus americanus genotypes 'resurrected' from century-long, soil-stored seed banks to ambient or elevated CO2 , varying levels of inundation, and the presence of a competing marsh grass, across two sites with different salinities. Comparisons of responses to global change factors among age cohorts and across provenances indicated that plasticity has evolved in five of the seven traits measured. Accounting for evolutionary factors (i.e. evolution and sources of heritable variation) in statistical models explained an additional 9-31% of trait variation. Our findings indicate that evolutionary factors mediate ecological responses to environmental change. The magnitude of evolutionary change in plant traits over the last century suggests that evolution could play a role in pacing future ecosystem response to environmental change.

Selection and Admixture in a Polytypic Aposematic Frog.

AbstractPhenotypic differentiation within polytypic species is often attributed to selection, particularly when selection might be acting on a trait that serves as a signal for predator avoidance and mate choice. We evaluated this hypothesis by examining phenotypic and genotypic clines between populations of the strawberry poison frog Oophaga pumilio, a polytypic species that exhibits aposematic color pattern variation that is thought to be subject to both natural and sexual selection. Our aim was to assess the extent of admixture and to estimate the strength of selection acting on coloration across a region of Panama where monomorphic populations of distinctly colored frogs are separated by polymorphic populations containing both color variants alongside intermediately colored individuals. We detected sharp clinal transitions across the study region, which is an expected outcome of strong selection, but we also detected evidence of widespread admixture, even at sites far from the phenotypic transition zone. Additionally, genotypic and phenotypic clines were neither concordant nor coincident, and with one exception, selection coefficients estimated from cline attributes were small. These results suggest that strong selection is not required for the maintenance of phenotypic divergence within polytypic species, challenging the long-standing notion that strong selection is implicit in the evolution of warning signals.

Rapid evolution of a coastal marsh ecosystem engineer in response to global change.

There is increasing evidence that global change can alter ecosystems by eliciting rapid evolution of foundational plants capable of shaping vital attributes and processes. Here we describe results of a field-scale exposure experiment and multilocus assays illustrating that elevated CO2 (eCO2) and nitrogen (N) enrichment can result in rapid shifts in genetic and genotypic variation in Phragmites australis, an ecologically dominant plant that acts as an ecosystem engineer in coastal marshes worldwide. Compared to control treatments, genotypic diversity declined over three years of exposure, especially to N enrichment. The magnitude of loss also increased over time under conditions of N enrichment. Comparisons of genotype frequencies revealed that proportional abundances shifted with exposure to eCO2 and N in a manner consistent with expected responses to selection. Comparisons also revealed evidence of tradeoffs that constrained exposure responses, where any particular genotype responded favorably to one factor rather than to different factors or to combinations of factors. These findings challenge the prevailing view that plant-mediated ecosystem outcomes of global change are governed primarily by differences in species responses to shifting environmental pressures and highlight the value of accounting for organismal evolution in predictive models to improve forecasts of ecosystem responses to global change.

Microbial mediation of salinity stress response varies by plant genotype and provenance over time.

Although it is becoming widely appreciated that microbes can enhance plant tolerance to environmental stress, the nature of microbial mediation of exposure responses is not well understood. We addressed this deficit by examining whether microbial mediation of plant responses to elevated salinity is contingent on the environment and factors intrinsic to the host. We evaluated the influence of contrasting environmental conditions relative to host genotype, provenance and evolution by conducting a common-garden experiment utilizing ancestral and descendant cohorts of Schoenoplectus americanus genotypes recovered from two 100+ year coastal marsh seed banks. We compared S. americanus productivity and trait variation as well as associated endophytic microbial communities according to plant genotype, provenance, and age cohort under high and low salinity stress with and without native soil inoculation. The magnitude and direction of microbial mediation of S. americanus responses to elevated salinity varied according to individual genotype, provenance, as well as temporal shifts in genotypic variation and G × E (gene by environment) interactions. Relationships differed between plant traits and the structure of endosphere communities. Our findings indicate that plant-microbe associations and microbial mediation of plant stress are not only context-dependent but also dynamic. Our results additionally suggest that evolution can shape the fate of marsh ecosystems by altering how microbes confer plant tolerance to pressures linked to global change.

Stream and ocean hydrodynamics mediate partial migration strategies in an amphidromous Hawaiian goby.

Partial migration strategies, in which some individuals migrate but others do not, are widely observed in populations of migratory animals. Such patterns could arise via variation in migratory behaviors made by individual animals, via genetic variation in migratory predisposition, or simply by variation in migration opportunities mediated by environmental conditions. Here we use spatiotemporal variation in partial migration across populations of an amphidromous Hawaiian goby to test whether stream or ocean conditions favor completing its life cycle entirely within freshwater streams rather than undergoing an oceanic larval migration. Across 35 watersheds, microchemical analysis of otoliths revealed that most adult Awaous stamineus were freshwater residents (62% of n = 316 in 2009, 83% of n = 274 in 2011), but we found considerable variation among watersheds. We then tested the hypothesis that the prevalence of freshwater residency increases with the stability of stream flows and decreases with the availability of dispersal pathways arising from ocean hydrodynamics. We found that streams with low variation of daily discharge were home to a higher incidence of freshwater residents in each survey year. The magnitude of the shift in freshwater residency between survey years was positively associated with predicted interannual variability in the success of larval settlement in streams on each island based on passive drift in ocean currents. We built on these findings by developing a theoretical model of goby life history to further evaluate whether mediation of migration outcomes by stream and ocean hydrodynamics could be sufficient to explain the range of partial migration frequency observed across populations. The model illustrates that the proportion of larvae entering the ocean and differential survival of freshwater-resident versus ocean-going larvae are plausible mechanisms for range-wide shifts in migration strategies. Thus, we propose that hydrologic variation in both ocean and stream environments contributes to spatiotemporal variation in the prevalence of migration phenotypes in A. stamineus. Our empirical and theoretical results suggest that the capacity for partial migration could enhance the persistence of metapopulations of diadromous fish when confronted with variable ocean and stream conditions.

Accounting for variability when resurrecting dormant propagules substantiates their use in eco-evolutionary studies.

There has been a steady rise in the use of dormant propagules to study biotic responses to environmental change over time. This is particularly important for organisms that strongly mediate ecosystem processes, as changes in their traits over time can provide a unique snapshot into the structure and function of ecosystems from decades to millennia in the past. Understanding sources of bias and variation is a challenge in the field of resurrection ecology, including those that arise because often-used measurements like seed germination success are imperfect indicators of propagule viability. Using a Bayesian statistical framework, we evaluated sources of variability and tested for zero-inflation and overdispersion in data from 13 germination trials of soil-stored seeds of Schoenoplectus americanus, an ecosystem engineer in coastal salt marshes in the Chesapeake Bay. We hypothesized that these two model structures align with an ecological understanding of dormancy and revival: zero-inflation could arise due to failed germinations resulting from inviability or failed attempts to break dormancy, and overdispersion could arise by failing to measure important seed traits. A model that accounted for overdispersion, but not zero-inflation, was the best fit to our data. Tetrazolium viability tests corroborated this result: most seeds that failed to germinate did so because they were inviable, not because experimental methods failed to break their dormancy. Seed viability declined exponentially with seed age and was mediated by seed provenance and experimental conditions. Our results provide a framework for accounting for and explaining variability when estimating propagule viability from soil-stored natural archives which is a key aspect of using dormant propagules in eco-evolutionary studies.

A century-long record of plant evolution reconstructed from a coastal marsh seed bank.

Evidence is mounting that climate-driven shifts in environmental conditions can elicit organismal evolution, yet there are sparingly few long-term records that document the tempo and progression of responses, particularly for plants capable of transforming ecosystems. In this study, we "resurrected" cohorts of a foundational coastal marsh sedge (Schoenoplectus americanus) from a time-stratified seed bank to reconstruct a century-long record of heritable variation in response to salinity exposure. Common-garden experiments revealed that S. americanus exhibits heritable variation in phenotypic traits and biomass-based measures of salinity tolerance. We found that responses to salinity exposure differed among the revived cohorts, with plants from the early 20th century exhibiting greater salinity tolerance than those from the mid to late 20th century. Fluctuations in salinity tolerance could reflect stochastic variation but a congruent record of genotypic variation points to the alternative possibility that the loss and gain in functionality are driven by selection, with comparisons to historical rainfall and paleosalinity records suggesting that selective pressures vary according to shifting estuarine conditions. Because salinity tolerance in S. americanus is tightly coupled to primary productivity and other vital ecosystem attributes, these findings indicate that organismal evolution merits further consideration as a factor shaping coastal marsh responses to climate change.

Invasion and rapid adaptation of guppies (Poecilia reticulata) across the Hawaiian Archipelago.

How much does natural selection, as opposed to genetic drift, admixture, and gene flow, contribute to the evolution of invasive species following introduction to a new environment? Here we assess how evolution can shape biological invasions by examining population genomic variation in non-native guppies (Poecilia reticulata) introduced to the Hawaiian Islands approximately a century ago. By examining 18 invasive populations from four Hawaiian islands and four populations from the native range in northern South America, we reconstructed the history of introductions and evaluated population structure as well as the extent of ongoing gene flow across watersheds and among islands. Patterns of differentiation indicate that guppies have developed significant population structure, with little natural or human-mediated gene flow having occurred among populations following introduction. Demographic modeling and admixture graph analyses together suggest that guppies were initially introduced to O'ahu and Maui and then translocated to Hawai'i and Kaua'i. We detected evidence for only one introduction event from the native range, implying that any adaptive evolution in introduced populations likely utilized the genetic variation present in the founding population. Environmental association tests accounting for population structure identified loci exhibiting signatures of adaptive variation related to predators and landscape characteristics but not nutrient regimes. When paired with high estimates of effective population sizes and detectable population structure, the presence of environment-associated loci supports the role of natural selection in shaping contemporary evolution of Hawaiian guppy populations. Our findings indicate that local adaptation may engender invasion success, particularly in species with life histories that facilitate rapid evolution. Finally, evidence of low gene flow between populations suggests that removal could be an effective approach to control invasive guppies across the Hawaiian archipelago.

Intraspecific variation in landform engineering across a restored salt marsh shoreline.

Ecosystem engineers that modify landforms can be valuable tools for restoring habitat, but their use has frequently resulted in unanticipated outcomes. Departures from expectations might arise because applications discount the possibility that geomorphic processes are influenced by heritable phenotypic variation. We conducted a field-scale common garden experiment to assess whether shoreline erosion reflects intraspecific variation in the landform engineer Spartina alterniflora. Replicated plots on a shoreline denuded by the Deepwater Horizon oil spill were revegetated using plants from four genetically distinct sources: the local population, a nonlocal population, and two nursery stocks. We assessed variation in biomass, tissue nutrients, and functional traits alongside soil shear strength, surface elevation, and shoreline erosion rates over 2 years. We found that productivity, traits, nutrient content, and erosion rates varied according to plant provenance. Erosion reflected traits like root architecture more so than coarser metrics of growth. Erosion was significantly higher in plots with nonlocal plants that exhibited lower productivity, likely due to nitrogen limitation. Our results indicate that restoration practices should account for intraspecific variation in landform engineers and that in situ trials should be performed at sites slated for restoration to evaluate donor source suitability, particularly if introductions might modify local populations.

Amplification of pathogenic Leptospira infection with greater abundance and co-occurrence of rodent hosts across a counter-urbanizing landscape.

Land use change can elevate disease risk by creating conditions beneficial to species that carry zoonotic pathogens. Observations of concordant global trends in increased pathogen prevalence or disease incidence and landscape change have generated concerns that urbanization could increase transmission risk of some pathogens. Yet host-pathogen relationships underlying transmission risk have not been well characterized within cities, even where contact between humans and species capable of transmitting pathogens of concern occurs. We addressed this deficit by testing the hypothesis that areas in cities experiencing greater population loss and infrastructure decline (i.e., counter-urbanization) can support a greater diversity of host species and a larger and more diverse pool of pathogens. We did so by characterizing pathogenic Leptospira infection relative to rodent host richness and abundance across a mosaic of abandonment in post-Katrina New Orleans (Louisiana, USA). We found that Leptospira infection loads were highest in areas that harboured increased rodent species richness (which ranged from one to four rodent species detected). Areas with greater host co-occurrence also harboured a greater abundance of hosts, including the host species most likely to carry high infection loads, indicating that Leptospira infection can be amplified by increases in overall and relative host abundance. Evidence of shared infection among rodent host species indicates that cross-species transmission of Leptospira probably increases infection at sites with greater host richness. Additionally, evidence that rodent co-occurrence and abundance and Leptospira infection load parallel abandonment suggests that counter-urbanization can elevate zoonotic disease risk within cities, particularly in underserved communities that are burdened with disproportionate concentrations of derelict properties.

In the heart of the city: Trypanosoma cruzi infection prevalence in rodents across New Orleans.

BACKGROUND: Trypanosoma cruzi - the causative agent of Chagas disease - is known to circulate in commensal pests, but its occurrence in urban environments is not well understood. We addressed this deficit by determining the distribution and prevalence of T. cruzi infection in urban populations of commensal and wild rodents across New Orleans (Louisiana, USA). We assessed whether T. cruzi prevalence varies according to host species identity and species co-occurrences, and whether T. cruzi prevalence varies across mosaics of abandonment that shape urban rodent demography and assemblage structure in the city. METHODS: Leveraging city-wide population and assemblage surveys, we tested 1428 rodents comprising 5 species (cotton rats, house mice, Norway rats, rice rats and roof rats) captured at 98 trapping sites in 11 study areas across New Orleans including nine residential neighborhoods and a natural area in Orleans Parish and a neighborhood in St. Bernard Parish. We also assayed Norway rats at one site in Baton Rouge (Louisiana, USA). We used chi-square tests to determine whether infection prevalence differed among host species, among study areas, and among trapping sites according to the number of host species present. We used generalized linear mixed models to identify predictors of T. cruzi infection for all rodents and each host species, respectively. RESULTS: We detected T. cruzi in all host species in all study areas in New Orleans, but not in Baton Rouge. Though overall infection prevalence was 11%, it varied by study area and trapping site. There was no difference in prevalence by species, but roof rats exhibited the broadest geographical distribution of infection across the city. Infected rodents were trapped in densely populated neighborhoods like the French Quarter. Infection prevalence seasonally varied with abandonment, increasing with greater abandonment during the summer and declining with greater abandonment during the winter. CONCLUSIONS: Our findings illustrate that T. cruzi can be widespread in urban landscapes, suggesting that transmission and disease risk is greater than is currently recognized. Our findings also suggest that there is disproportionate risk of transmission in historically underserved communities, which could reinforce long-standing socioecological disparities in New Orleans and elsewhere.

Singing in a silent spring: Birds respond to a half-century soundscape reversion during the COVID-19 shutdown.

Actions taken to control the coronavirus disease 2019 (COVID-19) pandemic have conspicuously reduced motor vehicle traffic, potentially alleviating auditory pressures on animals that rely on sound for survival and reproduction. Here, by comparing soundscapes and songs across the San Francisco Bay Area before and during the recent statewide shutdown, we evaluated whether a common songbird responsively exploited newly emptied acoustic space. We show that noise levels in urban areas were substantially lower during the shutdown, characteristic of traffic in the mid-1950s. We also show that birds responded by producing higher performance songs at lower amplitudes, effectively maximizing communication distance and salience. These findings illustrate that behavioral traits can change rapidly in response to newly favorable conditions, indicating an inherent resilience to long-standing anthropogenic pressures such as noise pollution.

Rhizosphere microbial communities reflect genotypic and trait variation in a salt marsh ecosystem engineer.

PREMISE: There is growing recognition that intraspecific genetic variation in plants can influence associated soil microbial communities, but the functional bridges linking plant genotype with microbial community structure are not well understood. This deficit is due in part to a prevailing focus on characterizing relationships between microbial communities and functional trait variation among plant species or across plant communities, rather than within a single species. METHODS: We examined whether and how spatiotemporal variation in salt marsh rhizosphere microbial communities reflect plant provenance (genotypic variation) and associated trait variation within an ecosystem engineer, Spartina alterniflora. We planted S. alterniflora from four genetically distinct source populations in replicate sets of experimental plots across a shoreline in southeastern Louisiana, USA. After 2 years, we measured functional plant traits and profiled microbial communities. RESULTS: Bacterial and fungal α-diversity and richness were significantly higher in winter than in summer and corresponded to plant trait variation associated with provenance. Notably, 20% of the variation in fungal community composition was explained by trait differences while bacterial community structure did not reflect plant provenance or trait variation. However, evidence was found suggesting that bacterial communities are indirectly shaped by the influence of plant provenance on soil physicochemical properties. CONCLUSIONS: This study illustrates that intraspecific genetic and corresponding trait variation in an ecosystem engineer can shape rhizosphere microbial communities, with fungal communities being more responsive than bacteria to the influence of plant provenance and associated trait variation. Our results highlight the potential relevance of plant intraspecific variation in plant-microbe-soil feedbacks shaping naturally depauperate ecosystems like salt marshes.

Deep sequencing reveals multiclonality and new discrete typing units of Trypanosoma cruzi in rodents from the southern United States.

BACKGROUND/PURPOSE: The parasitic protozoa Trypanosoma cruzi, is widely distributed throughout the Americas. We explored the nature of T. cruzi infection in small rodents from New Orleans (LA, USA), an enzootic region of the parasite in North America. METHODS: We characterized the full complement of discrete typing units (DTUs) in rodent hosts through next-generation metabarcoding, as conventional PCR and Sanger sequencing approaches only detect the dominant genotype in biological samples. We assayed DTU diversity in tissue samples from 6 T. cruzi PCR positive rodents. The intergenic region of the mini-exon gene was amplified and sequenced on a MiSeq platform. A total of 141 sequences were aligned using Muscle, and TCS networks were constructed to identify DTUs in the samples. RESULTS: We detected distinct and varying assemblages of DTUs in the rodent hosts. Highly diverse DTU assemblages were detected, with 6-32 haplotypes recovered per individual, spanning multiple DTUs (TcI,TcII, TcIV, TcV and TcVI). Haplotypes varied in frequencies from 82% to less than 0.1%. DTU composition varied according to the tissue analyzed. Rural and urban rodents carried similarly diverse DTU assemblages, though urban rodent species tended to harbor more haplotypes than their sylvatic counterparts. CONCLUSION: Our results affirm that mammalian hosts can concurrently harbor a diverse complement of parasites, and indicate that there is greater diversity of T. cruzi DTUs present in North America than previously thought. Further investigation is warranted to understand the role of commensal rodents as a reservoir for T. cruzi in sylvatic and peridomestic environments.

Migratory flexibility in native Hawai'ian amphidromous fishes.

We assessed the prevalence of life history variation across four of the five native amphidromous Hawai'ian gobioids to determine whether some or all exhibit evidence of partial migration. Analysis of otolith Sr.: Ca concentrations affirmed that all are amphidromous and revealed evidence of partial migration in three of the four species. We found that 25% of Lentipes concolor (n = 8), 40% of Eleotris sandwicensis (n = 20) and 29% of Stenogobius hawaiiensis (n = 24) did not exhibit a migratory life-history. In contrast, all individuals of Sicyopterus stimpsoni (n = 55) included in the study went to sea as larvae. Lentipes concolor exhibited the shortest mean larval duration (LD) at 87 days, successively followed by E. sandwicensis (mean LD = 102 days), S. hawaiiensis (mean LD = 114 days) and S. stimpsoni (mean LD = 120 days). These findings offer a fresh perspective on migratory life histories that can help improve efforts to conserve and protect all of these and other at-risk amphidromous species that are subject to escalating anthropogenic pressures in both freshwater and marine environments.

Evidence of local adaptation in a waterfall-climbing Hawaiian goby fish derived from coupled biophysical modeling of larval dispersal and post-settlement selection.

BACKGROUND: Local adaptation of marine and diadromous species is thought to be a product of larval dispersal, settlement mortality, and differential reproductive success, particularly in heterogeneous post-settlement habitats. We evaluated this premise with an oceanographic passive larval dispersal model coupled with individual-based models of post-settlement selection and reproduction to infer conditions that underlie local adaptation in Sicyopterus stimpsoni, an amphidromous Hawaiian goby known for its ability to climb waterfalls. RESULTS: Our model results demonstrated that larval dispersal is spatio-temporally asymmetric, with more larvae dispersed from the southeast (the Big Island) to northwest (Kaua'i) along the archipelago, reflecting prevailing conditions such as El Niño/La Niña oscillations. Yet connectivity is nonetheless sufficient to result in homogenous populations across the archipelago. We also found, however, that ontogenetic shifts in habitat can give rise to adaptive morphological divergence when the strength of predation-driven post-settlement selection crosses a critical threshold. Notably, our simulations showed that larval dispersal is not the only factor determining the likelihood of morphological divergence. We found adaptive potential and evolutionary trajectories of S. stimpsoni were greater on islands with stronger environmental gradients and greater variance in larval cohort morphology due to fluctuating immigration. CONCLUSIONS: Contrary to expectation, these findings indicate that immigration can act in concert with selection to favor local adaptation and divergence in species with marine larval dispersal. Further development of model simulations, parameterized to reflect additional empirical estimates of abiotic and biotic factors, will help advance our understanding of the proximate and ultimate mechanisms driving adaptive evolution, population resilience, and speciation in marine-associated species.

Estimating effective population size for a cestode parasite infecting three-spined sticklebacks.

Remarkably few attempts have been made to estimate contemporary effective population size (Ne) for parasitic species, despite the valuable perspectives it can offer on the tempo and pace of parasite evolution as well as coevolutionary dynamics of host-parasite interactions. In this study, we utilized multi-locus microsatellite data to derive single-sample and temporal estimates of contemporary Ne for a cestode parasite (Schistocephalus solidus) as well as three-spined stickleback hosts (Gasterosteus aculeatus) in lakes across Alaska. Consistent with prior studies, both approaches recovered small and highly variable estimates of parasite and host Ne. We also found that estimates of host Ne and parasite Ne were sensitive to assumptions about population genetic structure and connectivity. And, while prior work on the stickleback-cestode system indicates that physiographic factors external to stickleback hosts largely govern genetic variation in S. solidus, our findings indicate that stickleback host attributes and factors internal to the host - namely body length, genetic diversity and infection - shape contemporary Ne of cestode parasites.

Rat Lungworm Infection in Rodents across Post-Katrina New Orleans, Louisiana, USA.

Rat lungworm (Angiostrongylus cantonensis), a parasitic nematode that can cause eosinophilic meningitis in humans, was first detected in New Orleans, Louisiana, USA, in the mid-1980s and now appears to be widespread in the southeastern United States. We assessed the distribution, prevalence, and intensity of A. cantonensis infection in New Orleans by examining lung biopsy samples of rodents trapped at 96 sites in 9 areas in Orleans Parish and 1 area in neighboring St. Bernard Parish during May 2015 through February 2017. These areas were selected to capture contrasting levels of income, flooding, and pos-disaster landscape management after Hurricane Katrina in 2005. We detected A. cantonensis in all areas and in 3 of the 4 rat species trapped. Overall prevalence was ≈38% but varied by area, host species, and host species co-occurrence. Infection intensity also varied by host species. These findings suggest that socioecological analysis of heterogeneity in definitive and intermediate host infection could improve understanding of health risks across the city.

A century of genetic variation inferred from a persistent soil-stored seed bank.

Stratigraphic accretion of dormant propagules in soil can result in natural archives useful for studying ecological and evolutionary responses to environmental change. Few attempts have been made, however, to use soil-stored seed banks as natural archives, in part because of concerns over nonrandom attrition and mixed stratification. Here, we examine the persistent seed bank of Schoenoplectus americanus, a foundational brackish marsh sedge, to determine whether it can serve as a resource for reconstructing historical records of demographic and population genetic variation. After assembling profiles of the seed bank from radionuclide-dated soil cores, we germinated seeds to "resurrect" cohorts spanning the 20th century. Using microsatellite markers, we assessed genetic diversity and differentiation among depth cohorts, drawing comparisons to extant plants at the study site and in nearby and more distant marshes. We found that seed density peaked at intermediate soil depths. We also detected genotypic differences among cohorts as well as between cohorts and extant plants. Genetic diversity did not decline with depth, indicating that the observed pattern of differentiation is not due to attrition. Patterns of differentiation within and among extant marshes also suggest that local populations persist as aggregates of small clones, likely reflecting repeated seedling recruitment and low immigration from admixed regional gene pools. These findings indicate that persistent and stratified soil-stored seed banks merit further consideration as resources for reconstructing decadal- to century-long records that can lend insight into the tempo and nature of ecological and evolutionary processes that shape populations over time.