Bettez Neil D.

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Neil D.

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Now showing 1 - 6 of 6
  • Article
    Continental-scale homogenization of residential lawn plant communities
    (Elsevier, 2017-05-20) Wheeler, Megan M. ; Neill, Christopher ; Groffman, Peter M. ; Avolio, Meghan L. ; Bettez, Neil D. ; Cavender-Bares, Jeannine ; Roy Chowdhury, Rinku ; Darling, Lindsay ; Grove, J. Morgan ; Hall, Sharon J. ; Heffernan, James B. ; Hobbie, Sarah E. ; Larson, Kelli L. ; Morse, Jennifer L. ; Nelson, Kristen ; Ogden, Laura ; O'Neil-Dunne, Jarlath ; Pataki, Diane E. ; Trammell, Tara
    Residential lawns are highly managed ecosystems that occur in urbanized landscapes across the United States. Because they are ubiquitous, lawns are good systems in which to study the potential homogenizing effects of urban land use and management together with the continental-scale effects of climate on ecosystem structure and functioning. We hypothesized that similar homeowner preferences and management in residential areas across the United States would lead to low plant species diversity in lawns and relatively homogeneous vegetation across broad geographical regions. We also hypothesized that lawn plant species richness would increase with regional temperature and precipitation due to the presence of spontaneous, weedy vegetation, but would decrease with household income and fertilizer use. To test these predictions, we compared plant species composition and richness in residential lawns in seven U.S. metropolitan regions. We also compared species composition in lawns with understory vegetation in minimally-managed reference areas in each city. As expected, the composition of cultivated turfgrasses was more similar among lawns than among reference areas, but this pattern also held among spontaneous species. Plant species richness and diversity varied more among lawns than among reference areas, and more diverse lawns occurred in metropolitan areas with higher precipitation. Native forb diversity increased with precipitation and decreased with income, driving overall lawn diversity trends with these predictors as well. Our results showed that both management and regional climate shaped lawn species composition, but the overall homogeneity of species regardless of regional context strongly suggested that management was a more important driver.
  • Article
    Satisfaction, water and fertilizer use in the American residential macrosystem
    (IOPScience, 2016-02-29) Groffman, Peter M. ; Grove, J. Morgan ; Polsky, Colin ; Bettez, Neil D. ; Morse, Jennifer L. ; Cavender-Bares, Jeannine ; Hall, Sharon J. ; Heffernan, James B. ; Hobbie, Sarah E. ; Larson, Kelli L. ; Neill, Christopher ; Nelson, Kristen ; Ogden, Laura ; O'Neil-Dunne, Jarlath ; Pataki, Diane E. ; Roy Chowdhury, Rinku ; Locke, Dexter H.
    Residential yards across the US look remarkably similar despite marked variation in climate and soil, yet the drivers of this homogenization are unknown. Telephone surveys of fertilizer and irrigation use and satisfaction with the natural environment, and measurements of inherent water and nitrogen availability in six US cities (Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, Los Angeles) showed that the percentage of people using irrigation at least once in a year was relatively invariant with little difference between the wettest (Miami, 85%) and driest (Phoenix, 89%) cities. The percentage of people using fertilizer at least once in a year also ranged narrowly (52%–71%), while soil nitrogen supply varied by 10x. Residents expressed similar levels of satisfaction with the natural environment in their neighborhoods. The nature and extent of this satisfaction must be understood if environmental managers hope to effect change in the establishment and maintenance of residential ecosystems.
  • Article
    Climate and lawn management interact to control C4 plant distribution in residential lawns across seven U.S. cities.
    (Ecological Society of America, 2019-04-01) Trammell, Tara ; Pataki, Diane E. ; Still, Christopher J. ; Ehleringer, James R. ; Avolio, Meghan L. ; Bettez, Neil D. ; Cavender-Bares, Jeannine ; Groffman, Peter M. ; Grove, J. Morgan ; Hall, Sharon J. ; Heffernan, James B. ; Hobbie, Sarah E. ; Larson, Kelli L. ; Morse, Jennifer L. ; Neill, Christopher ; Nelson, Kristen ; O'Neil-Dunne, Jarlath ; Pearse, William D. ; Roy Chowdhury, Rinku ; Steele, Meredith K. ; Wheeler, Megan M.
    In natural grasslands, C4 plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C3 vs. C4 photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs. climatic controls on lawn species distributions. We measured herbaceous plant carbon isotope ratios (δ13C, index of C3/C4 relative abundance) and C4 cover in residential lawns across seven U.S. cities to determine how climate, lawn plant management, or interactions between climate and plant management influenced C4 lawn cover. We also calculated theoretical C4 carbon gain predicted by a plant physiological model as an index of expected C4 cover due to growing season climatic conditions in each city. Contrary to theoretical predictions, plant δ13C and C4 cover in urban lawns were more strongly related to mean annual temperature than to growing season temperature. Wintertime temperatures influenced the distribution of C4 lawn turf plants, contrary to natural ecosystems where growing season temperatures primarily drive C4 distributions. C4 cover in lawns was greatest in the three warmest cities, due to an interaction between climate and homeowner plant management (e.g., planting C4 turf species) in these cities. The proportion of C4 lawn species was similar to the proportion of C4 species in the regional grass flora. However, the majority of C4 species were nonnative turf grasses, and not of regional origin. While temperature was a strong control on lawn species composition across the United States, cities differed as to whether these patterns were driven by cultivated lawn grasses vs. weedy species. In some cities, biotic interactions with weedy plants appeared to dominate, while in other cities, C4 plants were predominantly imported and cultivated. Elevated CO2 and temperature in cities can influence C3/C4 competitive outcomes; however, this study provides evidence that climate and plant management dynamics influence biogeography and ecology of C3/C4 plants in lawns. Their differing water and nutrient use efficiency may have substantial impacts on carbon, water, energy, and nutrient budgets across cities.
  • Preprint
    Roads as nitrogen deposition hot spots
    ( 2013-01) Bettez, Neil D. ; Marino, Roxanne ; Howarth, Robert W. ; Davidson, Eric A.
    Mobile sources are the single largest source of nitrogen emissions to the atmosphere in the US. It is likely that a portion of mobile-source emissions are deposited adjacent to roads and thus not measured by traditional monitoring networks, which were designed to measure longterm and regional trends in deposition well away from emission sources. To estimate the magnitude of near-source nitrogen deposition, we measured concentrations of both dissolved inorganic nitrogen (DIN) and total (inorganic + organic) dissolved nitrogen (TDN) in throughfall (i.e., the nitrogen that comes through the forest canopy) along transects perpendicular to two moderately trafficked roads on Cape Cod in Falmouth MA, coupled with measurements of both DIN and TDN in bulk precipitation made in adjacent open fields at the same transect distances. We used the TDN throughfall data to estimate total nitrogen deposition, including dry gaseous nitrogen deposition in addition to wet deposition and dry particle deposition. There was no difference in TDN in the bulk collectors along the transects at either site; however TDN in the throughfall collectors was always higher closest to the road and decreased with distance. These patterns were driven primarily by differences in the inorganic N and not the organic N. Annual throughfall deposition was 8.7 (+0.4) and 6.8 (+0.5) TDN - kg N ha-1 yr-1 at sites 10 m and 150 m away from the road respectively. We also characterized throughfall away from a non-road edge (power line right-of-way) to test whether the increased deposition observed near road edges was due to deposition near emission sources or due to a physical, edge effect causing higher deposition. The increased deposition we observed near roads was due to increases in inorganic N especially NH4 +. This increased deposition was not the result of an edge effect; rather it is due to near source deposition of mobile source emissions. We scaled these results to the entire watershed and estimate that by not taking into account the effects of increased gaseous N deposition from mobile sources we are underestimating the amount of N deposition to the watershed by 13% - 25%.
  • Article
    Homogenization of plant diversity, composition, and structure in North American urban yards
    (John Wiley & Sons, 2018-02-15) Pearse, William D. ; Cavender-Bares, Jeannine ; Hobbie, Sarah E. ; Avolio, Meghan L. ; Bettez, Neil D. ; Roy Chowdhury, Rinku ; Darling, Lindsay ; Groffman, Peter M. ; Grove, J. Morgan ; Hall, Sharon J. ; Heffernan, James B. ; Learned, Jennifer ; Neill, Christopher ; Nelson, Kristen ; Pataki, Diane E. ; Ruddell, Benjamin L. ; Steele, Meredith K. ; Trammell, Tara
    Urban ecosystems are widely hypothesized to be more ecologically homogeneous than natural ecosystems. We argue that urban plant communities assemble from a complex mix of horticultural and regional species pools, and evaluate the homogenization hypothesis by comparing cultivated and spontaneously occurring urban vegetation to natural area vegetation across seven major U.S. cities. There was limited support for homogenization of urban diversity, as the cultivated and spontaneous yard flora had greater numbers of species than natural areas, and cultivated phylogenetic diversity was also greater. However, urban yards showed evidence of homogenization of composition and structure. Yards were compositionally more similar across regions than were natural areas, and tree density was less variable in yards than in comparable natural areas. This homogenization of biodiversity likely reflects similar horticultural source pools, homeowner preferences, and management practices across U.S. cities.
  • Article
    Ecological homogenization of urban USA
    (Ecological Society of America, 2014-02) Groffman, Peter M. ; Cavender-Bares, Jeannine ; Bettez, Neil D. ; Grove, J. Morgan ; Hall, Sharon J. ; Heffernan, James B. ; Hobbie, Sarah E. ; Larson, Kelli L. ; Morse, Jennifer L. ; Neill, Christopher ; Nelson, Kristen ; O'Neil-Dunne, Jarlath ; Ogden, Laura ; Pataki, Diane E. ; Polsky, Colin ; Roy Chowdhury, Rinku ; Steele, Meredith K.
    A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis–St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales.