Browsing by Subject "phenology"

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Climate and competition affect growth and survival of transplanted sugar maple seedlings along a 1700‐km gradient
(Wiley, 2017) Putnam, Rachel C
Plant species distributions, broadly shaped by climate, may also be constrained by other species. The degree to which biotic factors affect range limits is unclear, however, and few experimental studies have investigated both biotic and abiotic factors across and beyond a species’ range. We examined seedling survival and net growth for three years in contrasting canopy type (closed canopy vs. gap) and neighbor density (clipped vs. unclipped) environments for northern, central, and southern populations of sugar maple (Acer saccharum) representing a climate- of- origin gradient, experimentally planted from Arkansas, USA to Ontario, Canada at ten forested sites along a 1700- km transect spanning beyond the species’ range. We hypoth-esized that each population’s highest survival and growth would occur in its region of origin, with poorer performance in cooler or warmer areas. Refuting this hypothesis, seedlings of all three populations had greater growth and survival in sites increasingly warmer than their point of origin, although they did show poorer growth and survival at increasingly colder sites. We also hypothesized that maple survival and net growth near and beyond range margins are con-strained primarily by cold temperature limitation in the north, where we expected neighbors to facilitate survival, and by competition in the south, where we expected to enhance survival and growth by reducing neighbor density. Results partially supported the hypothesis concerning biotic interactions: in canopy gaps, understory neighbors enhanced maple growth at the cool-est sites but did not suppress growth as expected at the warmest sites. As the northern popula-tion grew and survived reasonably well beyond the northern range limit, and as all populations performed best at warmer sites, including beyond the southern range limit, there was tepid, if any, support for the hypothesis that climate regulated the northern limit and absolutely no support for the hypothesis that competition regulated the southern limit. Together, these three- year ﬁndings with juvenile trees suggest that sugar maple range limits may instead be con-strained by factors besides climate and competition, by those factors at another life stage, and/or by climate events such as heat waves, droughts, and cold snaps that occur at longer return intervals.
Climate of Minnesota II - The Agricultural and Minimum-Temperature-Free Seasons
(1963-06) Baker, Donald G.; Strub, Joseph H. Jr
Complete Data and Analysis for: Niche models differentiate potential impacts of two aquatic invasive plant species on native macrophytes
(2021-01-22) Verhoeven, Michael R.; Glisson, Wesley J.; Larkin, Daniel J.; michael.verhoeven.mrv@gmail.com; Verhoeven, Michael R; Minnesota Aquatic Invasive Species Research Center
The goal of our study was to elucidate the mechanisms by which two invasive aquatic plant species (Myriophyllum spicatum and Potamogeton crispus) interact with native plant communities in lakes in Minnesota, USA. We used an observational dataset of aquatic plant occurrences—and associated light availability, depth, and temperature—to construct probabilistic models of the ecological niches of 34 aquatic plant species. We then compared shared-ness of these niches between the two invasive aquatic plants and 32 native species to infer the degree of direct competitive interaction. This repository contains the complete dataset as a comma-separated-value file and Program R code necessary to replicate the data prep, exploration, analysis, and visualizations presented in the manuscript.
Costs and Benefits of Extended Leaf Phenology in Invasive Shrubs
(2019-01) O'Connell, Erin
Many woody invasive plants in North America develop leaves earlier and retain leaves later than their native associates, which could result in greater carbon gain. However, freezing temperatures and low light levels at northern latitudes constrain growing season length, potentially reducing the importance of spring and fall carbon gain. To investigate the costs and benefits of extended leaf phenology, I observed two years of leaf phenology and for one year estimated total carbon gain, measured growth, and tested the freezing tolerance of four native and four invasive woody shrubs growing in Duluth, MN. I conducted my study in a disturbed forest with greater canopy openness than commonly studied late successional forests, in order to explore these traits in a habitat typical of invasive species. The invaders leafed out simultaneously with native species in the spring and demonstrated an equally high freezing tolerance, but retained their leaves later in the autumn. In addition, invasive species assimilated less carbon during the summer than the native species. Therefore, extended fall phenology in invaders was critical to maintaining competitive levels of carbon gain and did not provide an advantage over native species. These findings suggest that invasive species may be able to take advantage of lengthening growing seasons and that freezing temperatures do not currently limit their northern expansion. Continued research should consider geography and latitude when studying woody invasive species phenology and physiology.
Ecological behavior of velvet longhorned beetle Trichoferus campestris (Coleoptera: Cerambycidae), including hosts and phenology
(2021-12) Haynes, Alexandra
Velvet longhorned beetle Trichoferus campestris (Faldermann) (Coleoptera: Cerambycidae) is a longhorned beetle native to eastern Russia and Asia. It has established populations in countries far beyond its native range, including the United States, but its ecological impacts remain unclear. The biology and behavior of T. campestris, such as preferred hosts and seasonal phenology, have not been thoroughly studied. Trichoferus campestris is thought to be polyphagous and univoltine, with a peak flight period in mid-summer, but few if any studies exist on these topics. Knowledge of these characteristics can assist with effective strategies for monitoring and managing nonnative species. Here, we investigate hosts and phenology of T. campestris. We quantify ovipositional preferences and larval/developmental performance using choice and no-choice assays comparing the suitability of material harvested from different tree species of the upper midwestern United States: black walnut, Juglans nigra; the ‘Honeycrisp’ apple cultivar, Malus domestica; sugar maple, Acer saccharum; and eastern white pine, Pinus strobus. We study differences in oviposition between Malus domestica branches with vs. without cankers as well. We complement these laboratory studies with catch data from field trapping experiments, analyzing trends among traps hung in various genera of trees. Finally, we used trap catch numbers and local temperature data to elucidate the phenology of T. campestris in Minneapolis and St. Paul, Minnesota, USA in the summers of 2019 and 2020.
The Effect Of Season Of Prescribed Fire On Richness And Abundance Of Breeding Bird Species And Vegetation Structure In Minnesota Lowland Brush Ecosystems
(2019-05) Hawkinson, Annie
Lowland brush ecosystems provide critical habitat for diverse breeding bird communities in the western Great Lakes region of the United States. These ecosystems are disturbance-dependent and historically experienced fires occurring throughout plant growing and dormant seasons. Disturbance in brushland landscapes influences woody vegetation structure, which can increase in extent, density, and height without frequent or effective disturbance events. Woody vegetation structure has been shown to be important for breeding bird communities in upland and forest systems, but this has not been studied in lowland brush ecosystems. Additionally, there are few studies on how bird communities and lowland brush vegetation structure respond to fire. Currently, lowland brush ecosystems in the Upper Midwest are predominately burned during spring months when plants are dormant. This may not mimic historical fire effects because before fire-suppression and control, fires occurred throughout snow free seasons, including summer and fall. In forests and grasslands, plant and bird species have been shown to respond distinctly to different seasons of fire, with the response of bird species being related to changes in vegetation structure and its role in nesting and foraging. No studies on season of fire have been done in lowland brush ecosystems. We assessed baseline models relating bird species richness, bird total abundance, and abundance of frequently detected bird species to woody vegetation structure in lowland brush ecosystems. Frequently detected bird species included golden-winged warbler (Vermivora chrysoptera), sedge wren (Cistothorus platensis), and veery (Catharus fuscescens) which are Minnesota Species in Greatest Conservation Need. We then used a Before-After-Control-Impact experimental design to evaluate the magnitude in change in response to spring, summer, and fall fire treatments of the same bird and vegetation variables. This allowed us to determine vegetation characteristics that are important to breeding birds and how the responses of birds and plants relate to season of fire. Stem height and stem height diversity, which was a measure of vertical structural diversity, were related to the most frequently detected bird species and bird species richness. Although these vegetation variables did not respond significantly to spring, summer, and fall fire treatments compared to controls, they exhibited decreasing trends after fires. Additionally, changes in stem height were nearly statistically significant. Veery and yellow warbler (Setophaga petechia) decreased in abundance after summer (veery) and spring and fall (yellow warbler) season treatments and were related to stem height in baseline explanatory models. We posit that these species decreased in abundance due to decreases in stem height. In contrast, chestnut-sided warblers (Setophaga pensylvanica) increased in abundance after spring and fall fires. This species was also related to stem height and the number of woody plant species. Therefore, chestnut-sided warblers may have been responded to additional changes in vegetation from fire and notably, chestnut-sided and yellow warblers exhibited opposite responses to the same fire seasons even though these species exhibit similar life history traits. Bird total abundance increased after summer and fall fires, the 2 seasons when prescribed fires are not typically conducted in the Upper Midwest. In our explanatory baseline models, the null model best explained bird total abundance and so although we were unable to relate this response to vegetation measurements, we suggest this response be considered in future management. Based on our results and the mix of responses to spring, summer, and fall fire seasons, conducting prescribed fires during different seasons may support different breeding bird species. The overall breeding bird community may also benefit, especially if prescribed fire is implemented during the summer when plants are growing. Adding summer burns to disturbance management-regimes that are often restricted to the spring in lowland brush ecosystems may also provide managers with larger burn-windows.
Effects of winter temperatures, spring degree-day accumulation, and insect population source on phenological synchrony between forest tent caterpillar and
(Elsevier, 2016) Uelmen, Johnny A.; Lindroth, Richard L; Tobin, Patrick C.; Reich, Peter B; Schwartzberg, Ezra G; Raffa, Kenneth F
Global climate change has the potential to dramatically alter multiple ecosystem processes, including herbivory. The development rates of both plants and insects are highly sensitive to temperature. Although considerable work has examined the effects of temperature on spring phenologies of plants and insects individually, few studies have examined how anticipated warming will influence their phenological synchrony. We applied elevated temperatures of 1.7 and 3.4 °C in a controlled chamberless outdoor experiment in northeastern Minnesota, USA to examine the relative responses in onset of egg eclosion by forest tent caterpillar (Malacosoma disstria Hübner) and budbreak of two of its major host trees (trembling aspen, Populus tremuloides Michaux, and paper birch, Betula papyrifera Marshall). We superimposed four insect population sources and two overwintering regimes onto these treatments, and computed degree-day models. Timing of egg hatch varied among population source, overwintering location, and spring temperature regime. As expected, the development rates of plants and insects advanced under warmer conditions relative to ambient controls. However, budbreak advanced more than egg hatch. The degree of phenological synchrony between M. disstria and each host plant was differentially altered in response to warming. The interval by which birch budbreak preceded egg hatch nearly doubled from ambient to +1.7 °C. In the case of aspen, the sequence changed from egg hatch preceding, to following, budbreak at +3.4 °C. Additionally, under temperature regimes simulating future conditions, some insect populations currently south of our study sites became more synchronous with the manipulated hosts than did currently coexisting insect populations. These findings reveal how climate warming can alter insect-host plant interactions, through changes in phenological synchrony, possibly driving host shifts among tree species and genotypes. They also suggest how herbivore variability, both among populations and within individual egg masses, may provide opportunities for adaptation, especially in species that are highly mobile and polyphagous.
Fall Raptor Migration Phenology and its Relationship with Weather
(2018-12) Steiner, Ryan
Changes in fall raptor migration phenology have been documented at hawk count sites across North America. Delays in fall migration phenology are the most common shift reported, however these changes vary from species to species. Changes in fall migration phenology are often attributed to climate change, but direct links to climate are rarely demonstrated. Those studies that do attempt to link the shifts to climate change often use global weather phenomena such as the North Atlantic Oscillation. Using updated methods, we examined fall migration phenology in 14 raptor species counted in 44 years at Hawk Ridge in Duluth, MN in relation to local and regional climate variables. Variables explored were related to temperature, favorable wind conditions, and cold fronts because these variables have been previously found to influence raptor migration. Weather variables were summarized using a principal components analysis. Raptor phenology was regressed against the top ten principal components using univariate models. Most raptors were found to be migrating later when temperatures were warmer. Favorable winds were also found to influence fall migration timing for most species, however some species responded to a greater percentage of the season having favorable winds, while others responded to greater wind strength of favorable winds. The weather variables used in this study provide a partial explanation for observed changes in migration phenology, but more study is needed to fully explore the mechanisms governing the timing of fall raptor migration.
Further re-analyses looking for effects of phylogenetic diversity on community biomass and stability
(Wiley, 2015) Cardinale, Bradley J; Venail, Patrick; Gross, Kevin; Oakley, Todd H; Narwani, Anita; Allan, Eric; Flombaum, Pedro; Joshi, Jasmin; Reich, Peter B; Tilman, David; van Ruijven, Jasper
Maximum carbon assimilation model for understory wood plants growing at Bagley Nature Area in Duluth, MN
(2020-05-26) O'Connell, Erin M; Savage, Jessica A; oconn877@d.umn.edu; O'Connell, Erin M; Savage research team
These data were collected and analyzed for a project comparing the leaf phenology, carbon gain, growth, and freezing susceptibility of invasive and native species. Maximum seasonal carbon assimilation was modeled for six plants per eight species growing in a 50-year-old mixed forest. The model is based on understory light availability on sunny days, carbon dioxide assimilation rates, and leaf area adjusted in the spring for expanding leaves and in the fall for senescing leaves.
Phenological data (2009-2013) for ten tree species grown under experimental warming in northern Minnesota, USA
(2020-03-27) Montgomery, Rebecca A; Stefanski, Artur; Reich, Peter B; Rice, Karen E; rebeccam@umn.edu; Montgomery, Rebecca A; University of Minnesota Forest Ecology Group
This dataset contains five years of data on time of budburst, growing degree days at the time of budburst, time of senescence and phenological growing season length phenology data for ten tree species native to Minnesota, USA. Data were collected in a long-term open-air warming experiment located a the Cloquet Forestry Center, Cloquet, MN, USA and the Hubachek Wilderness Research Center, Ely, MN, USA. The design was a 2 (site) X 2 (habitat) x 3 (warming treatment) factorial, with 6 replicates (2 per block) for a total of 72 7.1 m2 circular plots. Species include: Quercus rubra, Quercus macrocarpa, Pinus banksiana, Pinus strobus, Populus tremuloides, Betula papyrifera, Abies balsamea, Picea glauca, Acer rubrum, Acer saccharum. These data are released in conjunction with a publication.
Plant phenology and floral anatomy data observed from 2017 to 2020 on woody plants growing in Minnesota
(2021-09-21) McMann, Natalie; Peichel, Alexander; Savage, Jessica A; mcman110@d.umn.edu; McMann, Natalie; Savage research team
These data were collected for a project examining floral water loss and floral hydration in woody plants that flower before producing leaves. Floral phenology, bud mass, and surface area data was collected from at least 6 individuals of five species. Phenology and mass data were used to determine water uptake throughout bud development. Surface area data was used to standardize gas exchange measurements in a related dataset.
Plant phenology, growth, freezing damage, and carbon gain data observed from 2017 to 2018 on wood plants growing at Bagley Nature Area in Duluth, MN
(2020-05-26) O'Connell, Erin M; Savage, Jessica A; oconn877@d.umn.edu; O'Connell, Erin M; Savage research team
These data were collected for a project comparing the leaf phenology, carbon gain, growth, and freezing susceptibility of four invasive and four native species. Leaf phenology and stem growth were observed for ten individuals per understory wood shrubs species. Freezing damage was experimentally assessed for each species and minimum temperatures in the species' native and exotic ranges were determined. Carbon gain was modeled for six individuals per species based on photosynthetic light response curves, leaf phenology, and understory light.
Plant wood and reproductive anatomy collected from 2014 to 2016 on wood plants growing at the Arnold Arboretum in Boston, MA
(2019-07-16) Savage, Jessica A.; jsavage@d.umn.edu; Savage, Jessica A.; Savage research team
These data were collected for a project examining the relationship between vascular and floral phenology in plants that flower precocious before they have leaves. Reproductive and xylem data was collected on 5-6 individuals of 10 species with one species in each genus exhibiting precocious flowering.
The Role of Temperature in the Phenology of Temperate and Boreal Tree Species
(2023-02) Nanninga, Claudia
Dissertation AbstractIn the current era of climate change, the phenology of trees, i.e., the timing of seasonal life-cycle events, is evolving. Due to warming springs, leaf bud break has been observed to occur earlier worldwide, even though this trend has slowed in recent years. Because the phenology of trees can be important in determining range limits, annual net primary production, and interactions with other species, it is essential to understand how climate change might impact phenological timing in the future. This dissertation describes several laboratory experiments with the goal of elucidating the effect of some of the main cues, i.e., cold winter and warm spring temperatures, on the spring phenology of boreal and temperate tree species. With the help of others, I collected dormant twigs of temperate and boreal tree species at Cedar Creek, MN, and exposed them to different experimental conditions. In collaboration with the Technical University of Munich, Bavaria, I was also able to replicate some experiments in Germany to understand the different chilling and forcing needs of temperate and boreal species of the same genus, but different region. Dr. Sam Fahrner Ward (back then at the Entomology Department of the University of MN) and I additionally worked with tamarack seedlings and larch casebearer larvae to better understand if changes in the phenological synchrony of these interacting species could be responsible for recent larch casebearer outbreaks in MN. I found that for both Cedar Creek and Germany, prolonged chilling throughout the winter reduced the need for forcing/the time to bud break for the large majority of species, and that there were significant differences between species within the U.S. and Germany, and across continents. If chilling were reduced in the winter due to climate change, species with small chilling requirements could be disproportionally advantage by warmer springs, However, I also found that out of 14 species from Germany and the U.S., 7 species significantly reacted to chilling temperature and that 6 out of these 7 species broke bud faster when exposed to warmer chilling of up to 4.5ºC. In regions with very cold winter temperatures, such as MN, climate change induced winter warming could initially benefit species that prefer warmer chilling, while for species that prefer colder chilling, warmer winters could delay bud break if chilling requirements are not fully met. I also found that warmer chilling and forcing increased phenological synchrony between larch casebearer and tamarack, but only up to 27ºC of forcing, after which larval activation slowed down. Additionally, in growth chambers of 21ºC and warmer, casebearer larvae were unable to reach adulthood. Warmer winters and springs might increase synchrony of both species, which could benefit larch casebearer due to the availability of younger, more nutritious needles with reduced defense chemicals. However, in very warm springs, survivorship to adulthood might be drastically reduced.
Weighing the Risks and Benefits of Flowering Early for the Woody Perennial Prunus pumila (Rosaceae)
(2022-05) Lake Diver, Danielle
As global weather patterns become increasingly unpredictable, the need to study the impact of this phenomenon on natural and anthropocentric ecosystems alike is increasingly urgent. Based on climate change predictions for the rest of this century, much previous research has been conducted to reveal plants’ response to stress from heat and drought. However, fewer studies have focused on the response of perennial plants to false spring, or freezing after de-acclimation, another possible result of climate change. Plant phenology has already begun to advance by weeks since the middle of the twentieth century, which makes plants that flower and leaf out early particularly vulnerable to freezing damage from late spring frosts. Temperature during anthesis (when open flowers are present on a plant) has a significant impact on fertility, floral metabolism, and the production and quality of floral rewards that attract pollinators. Therefore, there may be advantages to flowering early that outstrip the potential risks, especially if pollinators also adjust their phenology to warming conditions. To determine whether earlier flowering plants were at risk for freezing damage, we first monitored a population of Prunus pumila with artificially delayed phenology over the course of the 2020 growing season. We measured flower and fruit number and mass, pollinator visitations, the effects of floral age on hand pollination, and seed germination. Consistent with previous studies, our results suggest that flowering time and temperature at anthesis affect reproductive success, with fewer fruits produced in warmer conditions. To build on this work, in 2021, we examined the effects of floral freezing on P. pumila pollinator attraction and reproductive success. Field-grown potted plants were exposed to one of two sub zero (°C) temperatures or a near-freezing control temperature. Flower samples were assessed for tissue damage through electrolyte leakage and stereo microscopy. In addition, a subset of flowers was hand pollinated or bagged to exclude insects and to gauge the effects of pollen limitation and selfing, respectively. Plants were then returned to the field and observed over the course of flowering for pollinator visitation and monitored for signs of successful fertilization and reproduction. This study showed that, in general, P. pumila buds and flowers are resistant to light freezing but not to hard freezing, but this difference did not affect overall pollinator visitation rate. Our findings will contribute to the current knowledge of Prunus, a global genus with high economic and ecologic value that could be greatly impacted by climate change.

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