SEARCH · Search USGS

Results for “Nature Plants”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

USGS2020

Book review of "Plant anatomy—A concept based approach to the structure of seed plants"

Plant Anatomy: A Concept-Based Approach to the Structure of Seed Plants by Crang, Lyons-Sobaski, and Wise is a beautifully-illustrated, 600+ page textbook highlighting the wonderful diversity of anatomical form in plants. The layout of the chapters follows many traditional plant anatomy textbooks. Plant Anatomy begins with an overview of plant morphology and proceeds through evolutionary time and across systems (Chapter 1. The Nature of Plants) before zooming into the microscopic, internal world of plant structures and their function (Chapter 2. Microscopy and Imaging through Chapter 8. Phloem). Quite fortunately, historical context is described throughout these sections, highlighting seminal studies that have shaped the plant sciences over the past 300+ years.

Plant Science Bulletin↗

USGS2010

Limiting factors of four rare plant species in `Ōla`A Forest of Hawai'i Volcanoes National Park

Three endangered or candidate endangered plant species native to `Ōla`a Forest ( Cyrtandra giffardii , ha`iwale; Phyllostegia floribunda , a mint with no common name; and Sicyos alba , `ānunu) were studied for more than 2 years to determine their stand structures, short-term mortality rates, patterns of reproductive phenology, success of fruit production, seed germination rates in the greenhouse, presence of soil seed bank, and survival of both natural and planted seedlings. The role of rodents as seed predators was evaluated for S. alba using seed offerings in open and closed stations. A 4th endangered species at a remote site in `Ōla`a ( Cyrtandra tintinnabula ) was visited to determine its stand structure and mortality rate. Cyrtandra giffardii displayed a stable population structure with many adults and few small or very large plants; the monitored population had a mortality rate of 7.3% over 3 years. Mortality of plantings from 2003-2004 in a re-introduced population of Phyllostegia floribunda was 21.4%. The stand structure of C. tintinnabula indicated a relatively stable population with both small and large plants present and a short-term mortality rate between visits of 14.5- 17.0%. Four groups of S. alba vines were monitored; 3 of these have persisted in place for at least 15 years. All species monitored had annual patterns of flower and fruit phenology, although male inflorescences of S. alba showed a subannual pattern. Successful transition of flowers to fruit was high for P. floribunda (51.5%), moderate for C. giffardii (23.3%) and undetermined for S. alba . High percentage viability was demonstrated for seeds of P. floribunda and S. alba (78.5-100% positive to strongly positive in tetrazolium tests), but seed viability was not tested for C. giffardii . Greenhouse germination rates were high for P. floribunda (88.0-92.0%), but variable and relatively low for C. giffardii (0-19.3%) and S. alba (4.0-11.1% in 2007 and 0 in 2008). No soil seed bank was detected for S. alba in 3 seasonal samplings, but P. floribunda was found to have a viable seed bank in April that persisted from at least the previous summer. Rodent predation of S. alba seeds was 93.3% in fruit offerings in accessible bait stations. Mortality of natural seedlings was high for both P. floribunda (90.2%) and S. alba (69.7%). Planted seedlings of P. floribunda produced flowers and fruit in their first year, and reproduction was higher in sunny plots than in shady plots. Mortality was high in both planting treatments, and survival rates did not differ significantly in sun and shade (χ 2 =0.48, df = 1, p = 0.490). Three planted seedlings of S. alba survived for 12-16 months but did not reproduce. Floral visitors were observed at C. giffardii and P. floribunda using digital video cameras and recorders. In almost 200 hours of observation, no visitors entered the flowers of C. giffardii , although 1 very small insect, either a micro-wasp (Hymenoptera) or fly (Diptera) was seen on the exterior of a corolla. In almost 300 hours of video observation, 3 floral visitors were identified at P. floribunda flowers. Honeybees ( Apis mellifera ) were likely pollinators, as they contacted both anthers and stigma of flowers. The mean visitation rate of honeybees was 0.003 visit/flower/hour, and visit duration ranged from 2 to 17 seconds. Fruit flies (Drosophilidae of undetermined species) crawled around flower interiors, but did not seem to forage for either nectar or pollen. Fruit fly mean visitation rate was 0.006 visit/flower/hour, and visit duration was 28 to 1,424 seconds. The 3rd observed insect visitor was an endemic geometrid moth caterpillar ( Lophoplusia giffardi ), which was seen feeding on foliage and flowers of P. floribunda . In conclusion, 2 of the 3 regularly-monitored rare plant species of `Ōla`a Forest appeared to have more than 1 limiting factor inhibiting the natural increase in their populations, while for P. floribunda the most important factor was high seedling mortality. Most plants of the monitored C. giffardii population appeared to be hybrids, probably with the more common species C. lysiosepala . Seed germination rates were low, and natural seedlings were not observed. Pollinators were not seen in many hours of observation, indicating that cross pollination is a rare or uncommon event. The re-introduced population of P. floribunda had relatively low mortality, and reproduction was successful with high rates of fruit formation from abundant flowers. Seed germination rates were high, and a soil seed bank was detected. Natural seedling recruitment was observed, but high seedling mortality indicated that this life stage was the most vulnerable in the species. The population of S. alba was small and the vine life form precluded an accurate estimate of the number of adult plants in `Ōla`a Forest. Natural dormancy was likely a factor in the observed low rate of seed germination. No soil seed bank was detected, and alien rodents were implicated as seed predators. Natural recruitment was observed at multiple sites in `Ōla`a, but seedling mortality was high. The cause of seedling mortality was not identified.

Hawaii↗

USGS2009

Symbiotic lifestyle expression by fungal endophytes and the adaptation of plants to stress: unraveling the complexities of intimacy

The fossil record indicates that fungal symbionts have been associated with plants since the Ordovician period (approximately 400 million years ago), when plants first became established on land (Pirozynski and Malloch, 1975; Redecker et al., 2000; Remy et al., 1994; Simon et al., 1993). Transitioning from aquatic to terrestrial habitats likely presented plants with new stresses, including periods of desiccation. Since symbiotic fungi are known to confer drought tolerance to plants (Bacon, 1993; Read and Camp, 1986), it has been suggested that fungal symbiosis was involved with or responsible for the establishment of land plants (Pirozynski and Malloch, 1975). Symbiosis was first defined by De Bary in 1879, and since that time, all plants in natural ecosystems have been found to be colonized with fungal and bacterial symbionts. It is clear that individual plants represent symbiotic communities with microorganisms associated in or on tissues below- and aboveground. There are two major classes of fungal symbionts associated with internal plant tissues: fungal endophytes that reside entirely within plants and may be associated with roots, stems leaves, or flowers; and mycorrhizal fungi that reside only in roots but extend out into the rhizosphere. In addition, fungal endophytes may be divided into two classes: (1) a relatively small number of fastidious species that are limited to a few monocot hosts (Clay and Schardl, 2002), and (2) a large number of tractable species with broad host ranges, including both monocots and eudicots (Stone et al., 2000). While significant resources and research have been invested in mycorrhizae and class 1 endophytes, comparatively little is known about class 2 endophytes, which may represent the largest group of fungal symbionts. This is partially because the symbiotic functionalities of class 2 endophytes have only recently been elucidated and shown to be responsible for the adaptation of some plants to high-stress environments (Redman et al., 1999, 2001, 2002a; Arnold et al., 2003; Dingle and McGee, 2003; Ernst et al., 2003). In this chapter, we focus on symbiotic interactions between class 2 endophytes and a variety of monocot and eudicot host species. Specifically, we will discuss the ability of endophytes to express more than one symbiotic lifestyle, fungal taxonomy vs. lifestyle expression, the adaptive nature of symbioses, mechanisms of symbiotically conferred stress tolerance, and the evolutionary implications of adaptive symbiosis. We will refer to class 2 endophytes as fungal endophytes throughout the text.

Book chapter↗

USGS2009

Effects of contaminated dredge spoils on wetland plant communities: A literature review

Contaminated dredge spoil is a national concern due to its scope and effects on biota, water quality, and the physical environment. This literature review discusses the effects of contaminated dredge spoils on wetland plant communities. Plant communities naturally shift over time with changing environmental conditions. Addition of toxins and nutrients and changes in hydrology may influence plant community structure. The storage and disposal of nutrient and metal contaminated dredge spoils may cause shifts in nearby plant communities. Shifts in species composition and diversity may not be observed for decades after nutrient enrichment, causing any disturbance to remain undetected. Plant community shifts often have great amounts of inertia and are difficult to reverse.

Book chapter↗

USGS2002

Palynology and palynostratigraphy of the Hell Creek Formation in North Dakota: A microfossil record of plants at the end of Cretaceous time

The Hell Creek Formation of North Dakota preserves a rich and varied palynoflora including pollen, spores, and algal cysts; this palynoflora provides insight into the nature of plant life in the region in late Maastrichtian time. This palynological record supplements extensive data from the same ancient vegetation preserved in the megafloral record, and it provides background biostratigraphic data necessary to determine the nature of the Cretaceous-Tertiary (K-T) boundary event. This study of the Hell Creek palynoflora is based upon occurrences of palynomorphs in 71 samples from 20 measured sections in Bowman and Slope Counties, southwestern North Dakota . The palynoflora documented includes 115 or more palynomorph species, 98 of which are described. Three new genera are proposed, three new species are described, and five new nomenclatural combinations are made. The new taxa are Palaeoisoetes gen. nov., Styxpollenites gen. nov., Tschudypollis gen. nov., Aquilapollenites marmarthensis sp. nov., Osmundacidites stanleyi sp. nov., Styxpollenites calamitas sp. nov., Polyatriopollenites levis (Stanley 1965) comb. nov., Palaeoisoetes subengelmannii (Elsik 1968) comb. nov., Triporopollenites triplicatus (Anderson 1960) comb. nov., Tschudypollis retusus (Anderson 1960) comb. nov., and Tschudypollis thalmannii (Anderson 1960) comb. nov. The palynofloral taxa include 67 angiosperms, eight gymnosperms, 19 pteridophytes, and three bryophytes. Of these, 33 are regarded as characteristically uppermost Cretaceous taxa (K taxa). A few of the K taxa do not range all the way to the K-T boundary. Extinction of the Hell Creek palynoflora at the K-T boundary is ∼30%. The Hell Creek Formation is within theWodehouseia spinata Assemblage Zone.

North Dakota↗

USGS2012

What are plants doing and when? Using plant phenology to facilitate sustainable natural resources management

Climate change models for the northern Rocky Mountains predict changes in temperature and water availability that in turn will alter vegetation. Changes include timing of plant life-history events, or phenology, such as green-up, flowering and senescence, and shifts in species composition. Moreover, climate changes may favor different species, such as nonnative, annual grasses over native species. Changes in vegetation could make forage for ungulates, sage-grouse, and livestock available earlier in the growing season, but shifts in species composition and phenology may also result in earlier senescence (die-off or dormancy) and reduced overall forage production.

Wyoming↗

USGS2009

Fungal endophytes: diversity and functional roles

All plants in natural ecosystems appear to be symbiotic with fungal endophytes. This highly diverse group of fungi can have profound impacts on plant communities through increasing fitness by conferring abiotic and biotic stress tolerance, increasing biomass and decreasing water consumption, or decreasing fitness by altering resource allocation. Despite more than 100 yr of research resulting in thousands of journal articles, the ecological significance of these fungi remains poorly characterized. Historically, two endophytic groups (clavicipitaceous (C) and nonclavicipitaceous (NC)) have been discriminated based on phylogeny and life history traits. Here, we show that NC-endophytes represent three distinct functional groups based on host colonization and transmission, in planta biodiversity and fitness benefits conferred to hosts. Using this framework, we contrast the life histories, interactions with hosts and potential roles in plant ecophysiology of C- and NC-endophytes, and highlight several key questions for future work in endophyte biology.

New Phytologist↗

USGS2024

Elemental composition and potential toxicity of the riverine macrophyte Podostemum ceratophyllum Michx. reflects land use in eastern North America

Land use influences surface water quality, often alleviating stoichiometric constraints on primary production and altering biogeochemical cycling. However, land use effects on nutrient content and potential trace metal accumulation in aquatic plants remain unclear, and high concentrations of metals and altered nutrient ratios could impact the health of herbivores and detritivores. We tested for land use effects on nutrient and trace metal accumulation in a widespread riverine macrophyte, Podostemum ceratophyllum , collected from 91 locations from Georgia to Maine, USA in 2014–2016. We quantified carbon (C), nitrogen (N), phosphorus (P), their molar and mass ratios, N and C stable isotopes, and 17 additional elements in dried plants collected from each location to estimate relationships between plant tissue content and watershed land use, which we quantified as agriculture, forest, and development. Decreasing forest cover was correlated with increasing δ 15 N, Mg, Mn, and P in Podostemum tissue. Increasing urban development was correlated with increasing δ 15 N, Mg and P, while increasing agriculture was correlated with a decrease in C: P and the concentrations of multiple metals, along with increases in P, Mg and δ 15 N. Decreases in ratios of N: P and C:P with increasing agriculture and urban development in the watershed indicate more rapid P storage relative to C and N in plant tissue, and increased resource quality of the plant to consumers in these watersheds. We also observed potentially toxic dietary concentrations of some trace metals (B, Cd, Tl, Zn) in plant tissue which could be related to the plant's natural herbivory defense system or to land use. We conclude that land use influences the elemental composition of P. ceratophyllum , and potentially the quality and toxicity of the plant to herbivores and detritivores in eastern North American rivers.

Science of the Total Environment↗

USGS2022

Modeling the impact of invasive species litter on conditions affecting its spread and potential regime shift

Many introduced plants pose invasion risks globally and threaten the biodiversity of native ecosystems. Such non-native plants can become invasive when they have advantages over native plants, such as having fewer natural enemies. Invasive plants often have the ability to alter ecosystem properties after they have become established, which can make it difficult to eliminate the invasive. In principle, this can cause a regime shift that may not be reversed through intense control efforts that increase mortality and reduce growth of the invasive species. Here we use spatially explicit agent-based modeling to simulate the invasion of an introduced tree species into a habitat occupied by a native species. The model describes an invasive tree with fast growth and high seed production and, in addition, produces litter that has a suppressive effect on native seedlings. These are properties, for example, shared by the invasive Melaleuca quinquenervia in southern Florida habitats. We use simulation modeling to test the following logical hypotheses: Partial suppression of native tree seedlings by the invasive tree's litter (1) will accelerate the spread of the invasive tree into native vegetation, (2) will impede efforts to control invasive spread through biocontrol, and (3) can cause a regime shift that is not reversed even if the biocontrol lowers invasive growth and reproduction to levels substantially lower than those of the native species. Additionally, (4) the earlier in the invasion biocontrol is introduced, the more effective it will be in reversing the invasion. The simulations support all four hypotheses. While these results highlight the potential for biocontrol of invasive tree species, our findings also suggest that successful elimination of positive litter feedbacks and invasive spread may critically depend on the timing of control efforts within the invasion process.

Ecological Modelling↗

USGS2008

More than 400 million years of evolution and some plants still can't make it on their own: Plant stress tolerance via fungal symbiosis

All plants in natural ecosystems are thought to be symbiotic with mycorrhizal and/or endophytic fungi. Collectively, these fungi express different symbiotic lifestyles ranging from parasitism to mutualism. Analysis of Colletotrichum species indicates that individual isolates can express either parasitic or mutualistic lifestyles depending on the host genotype colonized. The endophyte colonization pattern and lifestyle expression indicate that plants can be discerned as either disease, non-disease, or non-hosts. Fitness benefits conferred by fungi expressing mutualistic lifestyles include biotic and abiotic stress tolerance, growth enhancement, and increased reproductive success. Analysis of plant-endophyte associations in high stress habitats revealed that at least some fungal endophytes confer habitat-specific stress tolerance to host plants. Without the habitat-adapted fungal endophytes, the plants are unable to survive in their native habitats. Moreover, the endophytes have a broad host range encompassing both monocots and eudicots, and confer habitat-specific stress tolerance to both plant groups. ?? The Author [2008]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.

Conference Paper↗

USGS2014

Soil, plant, and terrain effects on natural perchlorate distribution in a desert landscape

Perchlorate (ClO 4 − ) is a contaminant that occurs naturally throughout the world, but little is known about its distribution and interactions in terrestrial ecosystems. The objectives of this Amargosa Desert, Nevada study were to determine (i) the local-scale distribution of shallow-soil (0–30 cm) ClO 4 − with respect to shrub proximity (far and near) in three geomorphic settings (shoulder slope, footslope, and valley floor); (ii) the importance of soil, plant, and terrain variables on the hillslope-distribution of shallow-soil and creosote bush [ Larrea tridentata (Sessé & Moc. ex DC.) Coville] ClO 4 − ; and (iii) atmospheric (wet plus dry, including dust) deposition of ClO 4 − in relation to soil and plant reservoirs and cycling. Soil ClO 4 − ranged from 0.3 to 5.0 μg kg −1 . Within settings, valley floor ClO 4 − was 17× less near shrubs due in part to enhanced leaching, whereas shoulder and footslope values were ∼2× greater near shrubs. Hillslope regression models (soil, R 2 = 0.42; leaf, R 2 = 0.74) identified topographic and soil effects on ClO 4 − deposition, transport, and cycling. Selective plant uptake, bioaccumulation, and soil enrichment were evidenced by leaf ClO 4 − concentrations and Cl − /ClO 4 − molar ratios that were ∼8000× greater and 40× less, respectively, than soil values. Atmospheric deposition ClO 4 − flux was 343 mg ha −1 yr −1 , ∼10× that for published southwestern wet-deposition fluxes. Creosote bush canopy ClO 4 − (1310 mg ha−1) was identified as a previously unrecognized but important and active reservoir. Nitrate δ 18 O analyses of atmospheric deposition and soil supported the leaf-cycled–ClO 4 − input hypothesis. This study provides basic data on ClO 4 − distribution and cycling that are pertinent to the assessment of environmental impacts in desert ecosystems and broadly transferable to anthropogenically contaminated systems.

Nevada↗

USGS2011

Status and limiting factors of three rare plant species in the coastal lowlands and mid-elevation woodlands of Hawai`i Volcanoes National Park

Two endangered plant species ( Portulaca sclerocarpa , `ihi mākole, and Sesbania tomentosa , `ōhai) and a species of concern ( Bobea timonioides , `ahakea) native to the coastal lowlands and dry mid-elevation woodlands of Hawai`i Volcanoes National Park were studied for more than two years to determine their stand structure, short-term mortality rates, patterns of reproductive phenology, success of fruit production, seed germination rates in the greenhouse, presence of soil seed bank, and survival of both natural and planted seedlings. The role of rodents as fruit and seed predators was evaluated using exclosures and seed offerings in open and closed stations or cages. Rodents were excluded from randomly selected plants of P. sclerocarpa and from branches of S. tomentosa, and flower and fruit production were compared to that of adjacent unprotected plants. Tagged S. tomentosa fruit were also monitored monthly to detect rodent predation.

Hawai'i↗

USGS2010

Nitrogen-limitation and invasive sweetclover impacts vary between two Great Plains plant communities

Yellow sweetclover is an exotic herbaceous legume common in the Great Plains of the US. Although woody legumes have been shown to affect ecosystem processes through nitrogen (N) fixation (i.e., they can be considered "transformers" sensu Richardson et al. (2000)), the same has not been shown for short-lived herbaceous species. The objectives of this study were to (1) quantify the effects of yellow sweetclover on N mineralization and nitrification and (2) assess the effects of N fertilization on two plant communities, badlands sparse vegetation and western wheatgrass prairie. We used in situ (in wheatgrass prairie) and laboratory incubations (for both plant communities) to assess N dynamics at sites with high and low sweetclover cover in the two plant communities. We found that both N mineralization and nitrification were higher in the high sweetclover plots in the sparse plant community, but not in the wheatgrass prairie. To assess fertilization effects and determine if nutrients or water were limiting at our sites, we conducted a field experiment with five resource addition treatments, (1) N, (2) N + water, (3) water, (4) phosphorus, and (5) no addition. Water was limiting in the wheatgrass prairie but contrary to expectation, N was not. In contrast, N was limiting in the sparse community, where a fertilization effect was seen in exotic forbs, especially the toxic invader Halogeton glomeratus . Our results emphasize the contingent nature of plant invasion in which effects are largely dependent on attributes of the recipient vegetation.

Great Plains↗

USGS2025

Why are non-native plants successful? Consistently fast economic traits and novel origin jointly explain abundance across US ecoregions

Are non-native plants abundant because they are non-native, and have advantages over native plants, or because they possess ‘fast’ resource strategies, and have advantages in disturbed environments? This question is central to invasion biology but remains unanswered. We quantified the relative importance of resource strategy and biogeographic origin in 69 441 plots across the conterminous United States containing 11 280 plant species. Non-native species had faster economic traits than native species in most plant communities (77%, 86% and 82% of plots for leaf nitrogen concentration, specific leaf area, and leaf dry matter content). Non-native species also had distinct patterns of abundance, but these were not explained by their fast traits. Compared with functionally similar native species, non-native species were (1) more abundant in plains and deserts, indicating the importance of biogeographic origin, and less abundant in forested ecoregions, (2) were more abundant where co-occurring species had fast traits, for example due to disturbance, and (3) showed weaker signals of local environmental filtering. These results clarify the nature of plant invasion: Although non-native plants have consistently fast economic traits, other novel characteristics and processes likely explain their abundance and, therefore, impacts.

conterminous United States↗

USGS2019

Fire, climate and changing forests

A changing climate implies potential transformations in plant demography, communities, and disturbances such as wildfire and insect outbreaks. How do these dynamics play out in terrestrial ecosystems across scales of space and time? “Vegetation type conversion” (VTC) is a term used to describe abrupt and long-lasting changes in vegetation structure and composition due to various kinds of perturbations. For example, it has long been observed that fire-adapted ecosystems such as the California chaparral shrublands are readily replaced by non-native annual grasses when humans increase fire frequency. Similar effects are being observed in Sonoran Desert plant communities, where invasion by non-native buffelgrass (Cenchrus ciliare) exposes a fire-sensitive plant community to high-intensity fires, which are lethal to the long-lived iconic Sonoran flora such as Saguaro cactus (Carnegiea gigantea). While type conversions following severe disturbance have been observed for some time, the mechanisms that underlay such changes are only recently coming to light. Threshold behavior is of particular concern: as various climate indices pass critical values, some ecosystems may be reaching points of no return where recovery to the earlier state is no longer possible. A recent publication in the Proceedings of the National Academy of Sciences, U.S., has now revealed that increased fire severity impairs post-fire forest regeneration, setting the stage for potential large-scale type conversion of western conifer forests.

Nature Plants↗

USGS2016

Climate change perils for dioecious plant species

Climate change, particularly increased aridity, poses a significant threat to plants and the biotic communities they support. Dioecious species may be especially vulnerable to climate change given that they often exhibit spatial segregation of the sexes, reinforced by physiological and morphological specialization of each sex to different microhabitats. In dimorphic species, the overexpression of a trait by one gender versus the other may become suppressed in future climates. Data suggest that males will generally be less sensitive to increased aridity than co-occurring females and, consequently, extreme male-biased sex ratios are possible in a significant number of populations. The effects of male-biased sex ratios are likely to cascade to dependent community members, especially those that are specialized on one sex.

Nature Plants↗

USGS2019

Potential vulnerability of 348 herbaceous species to atmospheric deposition of nitrogen and sulfur in the United States

Atmospheric nitrogen and sulfur pollution increased over much of the United States during the twentieth century from fossil fuel combustion and industrial agriculture. Despite recent declines, nitrogen and sulfur deposition continue to affect many plant communities in the United States, although which species are at risk remains uncertain. We used species composition data from >14,000 survey sites across the contiguous United States to evaluate the association between nitrogen and sulfur deposition and the probability of occurrence for 348 herbaceous species. We found that the probability of occurrence for 70% of species was negatively associated with nitrogen or sulfur deposition somewhere in the contiguous United States (56% for N, 51% for S). Of the species, 15% and 51% potentially decreased at all nitrogen and sulfur deposition rates, respectively, suggesting thresholds below the minimum deposition they receive. Although more species potentially increased than decreased with nitrogen deposition, increasers tended to be introduced and decreasers tended to be higher-value native species. More vulnerable species tended to be shorter with lower tissue nitrogen and magnesium. These relationships constitute predictive equations to estimate critical loads. These results demonstrate that many herbaceous species may be at risk from atmospheric deposition and can inform improvements to air quality policies in the United States and globally.

Contiguous United States↗

USGS2023

Ocean current patterns drive the worldwide colonization of eelgrass (Zostera marina)

Currents are unique drivers of oceanic phylogeography and thus determine the distribution of marine coastal species, along with past glaciations and sea-level changes. Here we reconstruct the worldwide colonization history of eelgrass ( Zostera marina L.), the most widely distributed marine flowering plant or seagrass from its origin in the Northwest Pacific, based on nuclear and chloroplast genomes. We identified two divergent Pacific clades with evidence for admixture along the East Pacific coast. Two west-to-east (trans-Pacific) colonization events support the key role of the North Pacific Current. Time-calibrated nuclear and chloroplast phylogenies yielded concordant estimates of the arrival of Z. marina in the Atlantic through the Canadian Arctic, suggesting that eelgrass-based ecosystems, hotspots of biodiversity and carbon sequestration, have only been present there for ~243 ky (thousand years). Mediterranean populations were founded ~44 kya, while extant distributions along western and eastern Atlantic shores were founded at the end of the Last Glacial Maximum (~19 kya), with at least one major refuge being the North Carolina region. The recent colonization and five- to sevenfold lower genomic diversity of the Atlantic compared to the Pacific populations raises concern and opportunity about how Atlantic eelgrass might respond to rapidly warming coastal oceans.

Nature Plants↗