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  • 1
    Electronic Resource
    Electronic Resource
    Experimental studies of seed predation in old-fields (1984)
    Springer
    Oecologia 65 (1984), S. 7-13 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a pair of experiments conducted in old-field habitats in southwestern Michigan (USA), we examined rates of seed loss to post-dispersal predators (ants and rodents). Seeds from 4–6 species of “biennial” plants were tested over a range of seed densities and habitat types. We found that seed removal was significantly higher in vegetated habitats than in areas of disturbed soil (both simulated small-animal diggings and a plowed field). In the undisturbed vegetation, seed losses ranged from 1–20% of seeds removed/day. An exclosure experiment demonstrated that ants and rodents foraged selectively for seeds of the six plant species tested. Rodents (Peromyscus maniculatus) fed preferentially on species producing large seeds (predominantly Tragopogon dubius). Ants (Myrmica lobicornus) foraged on smaller seeds, although their foraging preferences were not based strictly on seed size. Seed density had only a minor effect on predation rate over the range of densities tested. Predators, instead appeared to treat each experimental group of seeds as a single prey patch. Consequently, predation intensity was quite variable over distances of 〈20 m within a relatively homogeneous section of habitat. These field experiments provide initial estimates of seed losses to post-dispersal predators in old-field habitats. Rates of seed loss were generally less than those reported from desert or semi-arid habitats. However, for some old-field species, seed losses averaged an appreciable 10–20% day. The selective nature of the seed predators, plusthe relative patchiness of predation intensity in space, suggest that postdispersal seed predation can play a role in determining the distribution and/or abundance of old-field herbs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384455
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  • 2
    Electronic Resource
    Electronic Resource
    Resource competition and suppression of plants colonizing early successional old fields (1999)
    Springer
    Oecologia 118 (1999), S. 69-75 
    Details
    ISSN: 1432-1939
    Keywords: Key wordsAchillea millefolium ; Ambrosia artemisiifolia ; Belowground competition ; Nitrogen acquisition ; Old-field succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Early colonizing annual plants are rapidly suppressed in secondary succession on fertile midwestern old fields, while later colonizing perennials persist. Differences in competitive ability for above- and belowground resources may be partly responsible for differences in species persistence during succession, as both light and nutrient availability may change rapidly. We found that, although both above- and belowground competition suppress growth of colonizing plants, belowground competition was the dominant factor in the suppression of the annual Ambrosia artemisiifolia in 2nd-year-old fields near the W.K. Kellogg Biological Station in southwestern Michigan. Despite an ability to persist in later successional fields, seedling transplants of the perennial Achillea millefolium were also suppressed by above- and belowground competition, with belowground competition having the strongest effect. As in many old fields, nitrogen availability is the primary factor limiting plant productivity. There was no clear difference between the species in ability to compete for 15N from an enriched patch, although there was an indication of greater precision of foraging by Achillea. Life history differences between these species and consequent differences in the phenology of root growth relative to other old-field plants are likely to play a large role in the persistence of Achillea in successional fields where Ambrosia is suppressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050704
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  • 3
    Electronic Resource
    Electronic Resource
    Predictions of fate from rosette size in four “biennial” plant species: Verbascum thapsus, Oenothera biennis, Daucus carota, and Tragopogon dubius (1981)
    Springer
    Oecologia 48 (1981), S. 209-213 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Individual plants were marked in field populations of four biennial plant species, Verbascum thapsus L., Oenothera biennis L., Daucus carota L., and Tragopogon dubius Scop., and followed for 2 or 3 years. The relationship of both rosette size and age to the probability of an individual dying, remaining vegetative, or flowering was determined for each species. In all four species, a minimum size must be reached before flowering can be induced and above that minimum the probability of flowering increases directly with rosette size. Conversely, the probability of dying decreases with increasing rosette size. In general, the fate of a rosette appears to be independent of its age although in populations where the probability of death is high for individuals above the minimum size for flowering, the age of a rosette may influence its fate to some extent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347966
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  • 4
    Electronic Resource
    Electronic Resource
    Latitudinal variation in seed weight and flower number in Prunella vulgaris (1993)
    Springer
    Oecologia 93 (1993), S. 55-62 
    Details
    ISSN: 1432-1939
    Keywords: Flowering time ; Flower number ; Geographic variation ; Growing season length ; Seed weight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of seed-weight variation across altitudinal and latitudinal gradients have led to conflicting hypotheses regarding the selective value of this traint in relation to the length of the growing season. Growing-season length may also influence the evolution of seed number, and population differentiation in seed weight may be constrained by a negative genetic correlation between seed weight and seed number within populations. We examined variation in seed weight and an estimate of seed number (flower number) and the covariance of these traits among populations of Prunella vulgaris at five latitudes between northern Michigan and South Carolina. We measured seed weight and flower number in native habitats and in a common environment to determine the extent to which patterns observed in the field reflect genetic differentiation. We observed no genetically based variation in seed weight across the latitudinal gradient, although genetic variation among populations within a latitude was observed. In contrast to the lack of variation in seed weight, flower number increased clinally from northern Michigan to Tennessee in a common environment. Population mean flowering date in a common environment was successively later from north to south. Later-flowering individuals appear to achieve a larger size before flowering and consequently possess more resources for seed production. This difference may account for the greater flower production of late-flowering, southern populations. Independence of population mean seed weight and flower number across the latitudinal gradient suggests that population differentiation in seed weight has not been constrained by a trade-off between seed size and number within populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321191
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  • 5
    Electronic Resource
    Electronic Resource
    Fine root growth and demographic responses to nutrient patches in four old-field plant species (1993)
    Springer
    Oecologia 95 (1993), S. 61-64 
    Details
    ISSN: 1432-1939
    Keywords: Root proliferation ; Root demography ; Nutrient heterogeneity ; Root loraging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Proliferation of roots in a nutrient patch can occur either as a result of an increase in root length (morphological response) or by a change in root birth or death rates (demographic responses). In this study we attempted to distinguish between these two mechanisms of response to nutrient patches and to compare the responses of four old-field plant species (two annuals, two perennials). For all four species combined, there were significant increases in root numbers and root length in fertilized patches. Root proliferation in fertilized patches was largely due to increased birth (=branching) rates of new roots. However, there was also a significant increase in root death rates in the fertilized patches which reduced the magnitude of the increase in net root numbers. Plots for individual species suggested they differed in the magnitude and timing of root proliferation in fertilized patches due to differences in root birth and death rates. However, because of the limited sample size in this study, there was only a marginally significant difference among species in root birth rates, and no difference in death rates. Further studies are currently underway to better quantify species differences in the demographic mechanism, as well as magnitude, of response to nutrient patches and if this would affect the ability to exploit small-scale heterogeneity in soil resources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649507
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  • 6
    Electronic Resource
    Electronic Resource
    Seed mass and emergence time effects on performance of Panicum dichotomiflorum Michx. across environments (1991)
    Springer
    Oecologia 87 (1991), S. 270-278 
    Details
    ISSN: 1432-1939
    Keywords: Seed mass ; Emergence time ; Panicum dichotomiflorum ; Path analysis ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of seed mass and emergence time on growth and reproduction of the annual, C4 grass, Panicum dichotomiflorum Michx., were investigated in an experimental field study. Individual seeds of P. dichotomiflorum of known mass were sown into marked plots in four newly-abandoned fields that differed in soil nutrient availability, soil moisture and the time of the year in which they were abandoned. Seedling emergence was monitored daily for four weeks following sowing. In none of these fields was there any relationship between seed mass and emergence time. Analyses of covariance indicated that the effects of seed mass and emergence date on plant performance varied among fields. Seed mass affected performance in one field (SOUTH EARLY) where abiotic stress after emergence was high. In contrast, later emergence significantly reduced performance in all four fields. We used a path analysis to decompose the direct and indirect effects of seed mass and emergence time on plant performance in each field. The path analysis revealed that in all four fields, final weight had a significant positive effect on seed production. The effect of seed mass and emergence time had variable (and often opposite effects) on these traits. Seed mass only had a significant positive, direct effect on seed production in the most abiotically stressful field (SOUTH LATE). In the other fields, the effects of seed mass on fecundity were mediated by the effect on final weight. Thus, the effects of seed mass and emergence time on growth and reproduction in P. dichotomiflorum vary across environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325266
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  • 7
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    Linking ecology and economics for ecosystem management (2006)
    American Institute of Biological Sciences
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Institute of Biological Sciences, 2006. This article is posted here by permission of American Institute of Biological Sciences for personal use, not for redistribution. The definitive version was published in BioScience 56 (2006): 121–133, doi:10.1641/0006-3568(2006)056[0121:LEAEFE]2.0.CO;2.
    Description: This article outlines an approach, based on ecosystem services, for assessing the trade-offs inherent in managing humans embedded in ecological systems. Evaluating these trade-offs requires an understanding of the biophysical magnitudes of the changes in ecosystem services that result from human actions, and of the impact of these changes on human welfare. We summarize the state of the art of ecosystem services–based management and the information needs for applying it. Three case studies of Long Term Ecological Research (LTER) sites—coastal, urban, and agricultural—illustrate the usefulness, information needs, quantification possibilities, and methods for this approach. One example of the application of this approach, with rigorously established service changes and valuations taken from the literature, is used to illustrate the potential for full economic valuation of several agricultural landscape management options, including managing for water quality, biodiversity, and crop productivity.
    Description: This paper is the product of a working group sponsored by the National Center for Ecological Analysis and Synthesis (www.nceas.ucsb.edu) in June 2004.
    Keywords: Ecosystem services ; Valuation ; Ecosystem management ; Long Term Ecological Research (LTER) ; Trade-offs
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 268803 bytes
    Format: application/pdf
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  • 8
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    Cross-site comparisons of dryland ecosystem response to climate change in the US long-term ecological research network (2023)
    Oxford University Press
    Details
    Publication Date: 2023-02-25
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hudson, A. R., Peters, D. P. C., Blair, J. M., Childers, D. L., Doran, P. T., Geil, K., Gooseff, M., Gross, K. L., Haddad, N. M., Pastore, M. A., Rudgers, J. A., Sala, O., Seabloom, E. W., & Shaver, G. Cross-site comparisons of dryland ecosystem response to climate change in the US long-term ecological research network. Bioscience, 72(9), (2022): 889–907, https://doi.org/10.1093/biosci/biab134.
    Description: Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.
    Description: Funding was provided by the USDA-ARS SCINet Big Data Project (grant no. 0500–00093–001–00-D), and the National Science Foundation US LTER Program to New Mexico State University for the Jornada Basin (grant no. DEB 20–25166), Kansas State University for the Konza Prairie (grant no. DEB 2025849), the Kellogg Biological Station (grant no. DEB 1832042), Cedar Creek Ecosystem Science Reserve (grants no. DEB-1234162 and no. DEB-1831944), ARC (grant no. DEB-1637459), MCM (grant no. OPP-1637708), CAP (grant no. DEB-1832016), and SEV (grant no. DEB-1655499). Support was also provided by the Minnesota Supercomputer Institute and the University of Minnesota, Michigan State University AgBioResearch.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 9
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    Global change effects on plant communities are magnified by time and the number of global change factors imposed (2019)
    National Academy of Sciences
    Details
    Publication Date: 2019-08-19
    Description: Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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  • 10
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    Competitive effects of conspecific and herbaceous (weeds) plants on growth and branch architecture of Populus ×euramericana cv. Eugenei (1998)
    Canadian Science Publishing
    Details
    Publication Date: 1998-01-01
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Canadian Science Publishing
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