Ellie M Goud | Cornell University (original) (raw)

Papers by Ellie M Goud

Research paper thumbnail of Is variation in inter-annual precipitation a mechanism for maintaining plant metabolic diversity?

Research paper thumbnail of Integrated metabolic strategy: A framework for predicting the evolution of carbon‐water tradeoffs within plant clades

Journal of Ecology

1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evol... more 1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evolutionary driver of plant strategies across environments. Nonetheless, challenges in measuring carbon gain and water loss in ways that integrate over leaf lifetime have limited our understanding of the variation in and mechanistic bases of this tradeoff. Furthermore, the microevolution of plant traits within species versus the macroevolution of strategies among closely related species may not be the same, and accordingly, the latter must be addressed using comparative phylogenetic analyses. 2. Here we introduce the concept of 'integrated metabolic strategy' (IMS) to describe the ratio between carbon isotope composition (δ 13 C) and oxygen isotope composition above source water (Δ 18 O) of leaf cellulose. IMS is a measure of leaf-level conditions that integrate several mechanisms contributing to carbon gain (δ 13 C) and water loss (Δ 18 O) over leaf lifespan, with larger values reflecting higher metabolic efficiency and hence less of a tradeoff. We tested how IMS evolves among closely related yet ecologically diverse milkweed species, and subsequently addressed phe-notypic plasticity in response to water availability in species with divergent IMS. 3. Integrated metabolic strategy varied strongly among 20 Asclepias species when grown under controlled conditions, and phylogenetic analyses demonstrate species specific tradeoffs between carbon gain and water loss. Larger IMS values were associated with species from dry habitats, with larger carboxylation capacity , smaller stomatal conductance and smaller leaves; smaller IMS was associated with wet habitats, smaller carboxylation capacity, larger stomatal conductance and larger leaves. The evolution of IMS was dominated by changes in species' demand for carbon (δ 13 C) more so than water conservation (Δ 18 O). Although some individual physiological traits showed phylogenetic signal, IMS did not. 4. In response to experimental decreases in soil moisture, three species maintained similar IMS across levels of water availability because of proportional increases in δ 13 C and Δ 18 O (or little change in either), while one species increased IMS due to disproportional changes in δ 13 C relative to Δ 18 O. 5. Synthesis. IMS is a broadly applicable mechanistic tool; IMS variation among and within species may shed light on unresolved questions relating to the evolution and ecology of plant ecophysiological strategies.

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of What is Speciation, How Does It Occur, and Why Is It Important for Conservation?

CourseSource

Speciation provides a framework for classifying biodiversity on Earth and is a central concept in... more Speciation provides a framework for classifying biodiversity on Earth and is a central concept in evolutionary biology. To help undergraduate students learn about speciation, we designed a student-centered lesson that uses active-learning techniques (e.g., clicker questions, small group work, and whole class discussion) and compares multiple species concepts (morphological, biological, and phylogenetic) using giraffes as an example. Giraffes were chosen as the focus of this lesson because they are familiar and have broad appeal to students; are in danger of becoming extinct; and have ecological, economic, and cultural importance. Students also learn about contemporary giraffe conservation issues and the current debate in the literature regarding the total number of giraffe species. Students then apply their knowledge by working in small groups on speciation scenarios that highlight organisms across the tree of life. Student understanding is assessed using multiple-choice pre/post-test questions, in-class clicker questions with peer discussion, and exam questions. Here we provide details about the lesson and report that student learning is improved.

Research paper thumbnail of Seismic Line Disturbance Alters Soil Physical and Chemical Properties Across Boreal Forest and Peatland Soils

Frontiers in Earth Science

Research paper thumbnail of What is Speciation, How Does It Occur, and Why Is It Important for Conservation?

CourseSource

Speciation provides a framework for classifying biodiversity on Earth and is a central concept in... more Speciation provides a framework for classifying biodiversity on Earth and is a central concept in evolutionary biology. To help undergraduate students learn about speciation, we designed a student-centered lesson that uses active-learning techniques (e.g., clicker questions, small group work, and whole class discussion) and compares multiple species concepts (morphological, biological, and phylogenetic) using giraffes as an example. Giraffes were chosen as the focus of this lesson because they are familiar and have broad appeal to students; are in danger of becoming extinct; and have ecological, economic, and cultural importance. Students also learn about contemporary giraffe conservation issues and the current debate in the literature regarding the total number of giraffe species. Students then apply their knowledge by working in small groups on speciation scenarios that highlight organisms across the tree of life. Student understanding is assessed using multiple-choice pre/post-test questions, in-class clicker questions with peer discussion, and exam questions. Here we provide details about the lesson and report that student learning is improved.

Research paper thumbnail of Integrated metabolic strategy: A framework for predicting the evolution of carbon-water tradeoffs within plant clades

Journal of Ecology, 2019

1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evol... more 1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evolutionary driver of plant strategies across environments. Nonetheless, challenges in measuring carbon gain and water loss in ways that integrate over leaf lifetime have limited our understanding of the variation in and mechanistic bases of this tradeoff. Furthermore, the microevolution of plant traits within species versus the macroevolution of strategies among closely related species may not be the same, and accordingly, the latter must be addressed using comparative phylogenetic analyses. 2. Here we introduce the concept of 'integrated metabolic strategy' (IMS) to describe the ratio between carbon isotope composition (δ 13 C) and oxygen isotope composition above source water (Δ 18 O) of leaf cellulose. IMS is a measure of leaf-level conditions that integrate several mechanisms contributing to carbon gain (δ 13 C) and water loss (Δ 18 O) over leaf lifespan, with larger values reflecting higher metabolic efficiency and hence less of a tradeoff. We tested how IMS evolves among closely related yet ecologically diverse milkweed species, and subsequently addressed phe-notypic plasticity in response to water availability in species with divergent IMS. 3. Integrated metabolic strategy varied strongly among 20 Asclepias species when grown under controlled conditions, and phylogenetic analyses demonstrate species specific tradeoffs between carbon gain and water loss. Larger IMS values were associated with species from dry habitats, with larger carboxylation capacity , smaller stomatal conductance and smaller leaves; smaller IMS was associated with wet habitats, smaller carboxylation capacity, larger stomatal conductance and larger leaves. The evolution of IMS was dominated by changes in species' demand for carbon (δ 13 C) more so than water conservation (Δ 18 O). Although some individual physiological traits showed phylogenetic signal, IMS did not. 4. In response to experimental decreases in soil moisture, three species maintained similar IMS across levels of water availability because of proportional increases in δ 13 C and Δ 18 O (or little change in either), while one species increased IMS due to disproportional changes in δ 13 C relative to Δ 18 O. 5. Synthesis. IMS is a broadly applicable mechanistic tool; IMS variation among and within species may shed light on unresolved questions relating to the evolution and ecology of plant ecophysiological strategies.

Research paper thumbnail of Plant community composition along a peatland margin follows alternate successional pathways after hydrologic disturbance.

Acta Oecologica, 2018

Hydrological disturbances can alter the structure and function of ecosystems by changing plant sp... more Hydrological disturbances can alter the structure and function of ecosystems by changing plant species composition over time. Peatlands in the northern hemisphere are particularly sensitive to global change drivers related to soil water availability, such as drought and drainage, because of important ecohydrological feedbacks between species composition and water table position. Here, we examined the plant community structure and environmental drivers of species distributions over two growing seasons along a bog – margin gradient, pre- and post-disturbance by beaver activity. Pond drainage resulted in seasonal average water table depth 8–24 cm lower in the second season. Five plant communities corresponded to changes in water table depth and acidity: bog, poor fen, meadow, mudflat and pond. Plant cover increased in meadow and mudflat communities, decreased in the pond community and did not differ between years in bog and poor fen communities. Changes in species abundance between years showed signs of alternate successional pathways: one that favors Sphagnum moss and bog community expansion and another pathway that favors meadow and mudflat expansion. This study highlights the non-linear successional trajectory of plant communities with changes in water table depth, which has implications for land management goals that aim to conserve the ecological integrity of peatland ecosystems.

Research paper thumbnail of Leaf stable isotopes suggest shared ancestry is an important driver of functional diversity.

Oecologia, 2018

Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often reg... more Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often regarded as outcomes of environmental selection. This is likely true, but the role of evolutionary history may also be important in shaping patterns of functional diversity. Here, we used leaf C and N stable isotope ratios (δ13C, δ15N) as integrators of physiological processes to assess the relative roles of phylogenetic history and environment in a diverse group of Ericaceae species native to North America. We found strong phylogenetic signal in both leaf δ13C and δ15N, suggesting that close relatives have similar physiological strategies. The signal of phylogeny was generally stronger than that of the local environment. However, within some specialized environments (e.g., wetlands, sandy soils), we found environmental effects and/or niche conservatism. Phylogenetic signal in δ13C appears to be most closely related to the constraints on metabolic demand and supply of C, and δ15N appears to be most strongly related to mycorrhizal associations within the family.

Research paper thumbnail of Diversity and abundance of litter-dwelling arthropods increase with time-since-burn in a Florida scrub ecosystem Diversity and abundance of litter-dwelling arthropods increase with time-since- burn in a Florida scrub ecosystem

Biodiversity, 2017

Fire is an important disturbance that can impact biodiversity and ecosystem functions. Although f... more Fire is an important disturbance that can impact biodiversity and ecosystem functions. Although fire impacts have been well studied in plants and some animals, the effects of fire on litter-dwelling arthropods remain poorly documented. I investigated the effect of time-since-burn on litter-dwelling arthropods in a Florida scrub ecosystem. I measured total arthropod richness and diversity as well as arachnid detritivore and predator abundance along a time-since-burn chronosequence. Arthropod richness and diversity and arachnid abundance significantly increased within 8 years post-burn. Arthropod richness and diversity and arachnid abundance did not differ between 8 and 89 years since last burn. These results demonstrate that litter-dwelling arthropods can quickly re-establish their community composition within 8 years after a burn, which may have important consequences for litter decomposition and nutrient cycling rates over successional time.

Research paper thumbnail of Predicting peatland carbon fluxes from non-destructive plant traits

Functional Ecology, 2017

Determining the plant traits that best predict carbon (C) storage is increasingly important as gl... more Determining the plant traits that best predict carbon (C) storage is increasingly important as global change drivers will affect plant species composition and ecosystem C cycling. Despite the critical role of peatlands in the global C cycle, trait-flux relationships in peatlands are relatively unknown.
We assessed the ability of four non-destructive plant traits to predict carbon dioxide (CO2) and methane (CH4) fluxes over two growing seasons in a temperate peatland in Ontario, Canada. We examined relationships between C-fluxes and leaf area, leaf persistence (deciduous, evergreen), growth form (woody, herbaceous), and aerenchyma tissue. To explore potential inconsistencies between different scales of data aggregation, traits were analysed at the level of plots, species and microsites.
CO2 fluxes showed a positive relationship with leaf area and leaf persistence, and a negative relationship with proportion of woody species. CH4 fluxes showed a positive relationship with aerenchyma and leaf area. The significance of trait-flux relationships differed based on whether data were averaged at the level of plot, species or microsite.
We recommend applying leaf area as a non-destructive trait to other systems where it is not ideal to measure traits destructively. A better understanding of the relationships between above and belowground traits is likely needed to further explain variation in ecosystem respiration and CH4 fluxes from plant traits.

Research paper thumbnail of Is variation in inter-annual precipitation a mechanism for maintaining plant metabolic diversity?

Research paper thumbnail of Integrated metabolic strategy: A framework for predicting the evolution of carbon‐water tradeoffs within plant clades

Journal of Ecology

1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evol... more 1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evolutionary driver of plant strategies across environments. Nonetheless, challenges in measuring carbon gain and water loss in ways that integrate over leaf lifetime have limited our understanding of the variation in and mechanistic bases of this tradeoff. Furthermore, the microevolution of plant traits within species versus the macroevolution of strategies among closely related species may not be the same, and accordingly, the latter must be addressed using comparative phylogenetic analyses. 2. Here we introduce the concept of 'integrated metabolic strategy' (IMS) to describe the ratio between carbon isotope composition (δ 13 C) and oxygen isotope composition above source water (Δ 18 O) of leaf cellulose. IMS is a measure of leaf-level conditions that integrate several mechanisms contributing to carbon gain (δ 13 C) and water loss (Δ 18 O) over leaf lifespan, with larger values reflecting higher metabolic efficiency and hence less of a tradeoff. We tested how IMS evolves among closely related yet ecologically diverse milkweed species, and subsequently addressed phe-notypic plasticity in response to water availability in species with divergent IMS. 3. Integrated metabolic strategy varied strongly among 20 Asclepias species when grown under controlled conditions, and phylogenetic analyses demonstrate species specific tradeoffs between carbon gain and water loss. Larger IMS values were associated with species from dry habitats, with larger carboxylation capacity , smaller stomatal conductance and smaller leaves; smaller IMS was associated with wet habitats, smaller carboxylation capacity, larger stomatal conductance and larger leaves. The evolution of IMS was dominated by changes in species' demand for carbon (δ 13 C) more so than water conservation (Δ 18 O). Although some individual physiological traits showed phylogenetic signal, IMS did not. 4. In response to experimental decreases in soil moisture, three species maintained similar IMS across levels of water availability because of proportional increases in δ 13 C and Δ 18 O (or little change in either), while one species increased IMS due to disproportional changes in δ 13 C relative to Δ 18 O. 5. Synthesis. IMS is a broadly applicable mechanistic tool; IMS variation among and within species may shed light on unresolved questions relating to the evolution and ecology of plant ecophysiological strategies.

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of Linear Disturbances Shift Boreal Peatland Plant Communities Toward Earlier Peak Greenness

Journal of Geophysical Research: Biogeosciences

Research paper thumbnail of What is Speciation, How Does It Occur, and Why Is It Important for Conservation?

CourseSource

Speciation provides a framework for classifying biodiversity on Earth and is a central concept in... more Speciation provides a framework for classifying biodiversity on Earth and is a central concept in evolutionary biology. To help undergraduate students learn about speciation, we designed a student-centered lesson that uses active-learning techniques (e.g., clicker questions, small group work, and whole class discussion) and compares multiple species concepts (morphological, biological, and phylogenetic) using giraffes as an example. Giraffes were chosen as the focus of this lesson because they are familiar and have broad appeal to students; are in danger of becoming extinct; and have ecological, economic, and cultural importance. Students also learn about contemporary giraffe conservation issues and the current debate in the literature regarding the total number of giraffe species. Students then apply their knowledge by working in small groups on speciation scenarios that highlight organisms across the tree of life. Student understanding is assessed using multiple-choice pre/post-test questions, in-class clicker questions with peer discussion, and exam questions. Here we provide details about the lesson and report that student learning is improved.

Research paper thumbnail of Seismic Line Disturbance Alters Soil Physical and Chemical Properties Across Boreal Forest and Peatland Soils

Frontiers in Earth Science

Research paper thumbnail of What is Speciation, How Does It Occur, and Why Is It Important for Conservation?

CourseSource

Speciation provides a framework for classifying biodiversity on Earth and is a central concept in... more Speciation provides a framework for classifying biodiversity on Earth and is a central concept in evolutionary biology. To help undergraduate students learn about speciation, we designed a student-centered lesson that uses active-learning techniques (e.g., clicker questions, small group work, and whole class discussion) and compares multiple species concepts (morphological, biological, and phylogenetic) using giraffes as an example. Giraffes were chosen as the focus of this lesson because they are familiar and have broad appeal to students; are in danger of becoming extinct; and have ecological, economic, and cultural importance. Students also learn about contemporary giraffe conservation issues and the current debate in the literature regarding the total number of giraffe species. Students then apply their knowledge by working in small groups on speciation scenarios that highlight organisms across the tree of life. Student understanding is assessed using multiple-choice pre/post-test questions, in-class clicker questions with peer discussion, and exam questions. Here we provide details about the lesson and report that student learning is improved.

Research paper thumbnail of Integrated metabolic strategy: A framework for predicting the evolution of carbon-water tradeoffs within plant clades

Journal of Ecology, 2019

1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evol... more 1. The fundamental tradeoff between carbon gain and water loss has long been predicted as an evolutionary driver of plant strategies across environments. Nonetheless, challenges in measuring carbon gain and water loss in ways that integrate over leaf lifetime have limited our understanding of the variation in and mechanistic bases of this tradeoff. Furthermore, the microevolution of plant traits within species versus the macroevolution of strategies among closely related species may not be the same, and accordingly, the latter must be addressed using comparative phylogenetic analyses. 2. Here we introduce the concept of 'integrated metabolic strategy' (IMS) to describe the ratio between carbon isotope composition (δ 13 C) and oxygen isotope composition above source water (Δ 18 O) of leaf cellulose. IMS is a measure of leaf-level conditions that integrate several mechanisms contributing to carbon gain (δ 13 C) and water loss (Δ 18 O) over leaf lifespan, with larger values reflecting higher metabolic efficiency and hence less of a tradeoff. We tested how IMS evolves among closely related yet ecologically diverse milkweed species, and subsequently addressed phe-notypic plasticity in response to water availability in species with divergent IMS. 3. Integrated metabolic strategy varied strongly among 20 Asclepias species when grown under controlled conditions, and phylogenetic analyses demonstrate species specific tradeoffs between carbon gain and water loss. Larger IMS values were associated with species from dry habitats, with larger carboxylation capacity , smaller stomatal conductance and smaller leaves; smaller IMS was associated with wet habitats, smaller carboxylation capacity, larger stomatal conductance and larger leaves. The evolution of IMS was dominated by changes in species' demand for carbon (δ 13 C) more so than water conservation (Δ 18 O). Although some individual physiological traits showed phylogenetic signal, IMS did not. 4. In response to experimental decreases in soil moisture, three species maintained similar IMS across levels of water availability because of proportional increases in δ 13 C and Δ 18 O (or little change in either), while one species increased IMS due to disproportional changes in δ 13 C relative to Δ 18 O. 5. Synthesis. IMS is a broadly applicable mechanistic tool; IMS variation among and within species may shed light on unresolved questions relating to the evolution and ecology of plant ecophysiological strategies.

Research paper thumbnail of Plant community composition along a peatland margin follows alternate successional pathways after hydrologic disturbance.

Acta Oecologica, 2018

Hydrological disturbances can alter the structure and function of ecosystems by changing plant sp... more Hydrological disturbances can alter the structure and function of ecosystems by changing plant species composition over time. Peatlands in the northern hemisphere are particularly sensitive to global change drivers related to soil water availability, such as drought and drainage, because of important ecohydrological feedbacks between species composition and water table position. Here, we examined the plant community structure and environmental drivers of species distributions over two growing seasons along a bog – margin gradient, pre- and post-disturbance by beaver activity. Pond drainage resulted in seasonal average water table depth 8–24 cm lower in the second season. Five plant communities corresponded to changes in water table depth and acidity: bog, poor fen, meadow, mudflat and pond. Plant cover increased in meadow and mudflat communities, decreased in the pond community and did not differ between years in bog and poor fen communities. Changes in species abundance between years showed signs of alternate successional pathways: one that favors Sphagnum moss and bog community expansion and another pathway that favors meadow and mudflat expansion. This study highlights the non-linear successional trajectory of plant communities with changes in water table depth, which has implications for land management goals that aim to conserve the ecological integrity of peatland ecosystems.

Research paper thumbnail of Leaf stable isotopes suggest shared ancestry is an important driver of functional diversity.

Oecologia, 2018

Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often reg... more Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often regarded as outcomes of environmental selection. This is likely true, but the role of evolutionary history may also be important in shaping patterns of functional diversity. Here, we used leaf C and N stable isotope ratios (δ13C, δ15N) as integrators of physiological processes to assess the relative roles of phylogenetic history and environment in a diverse group of Ericaceae species native to North America. We found strong phylogenetic signal in both leaf δ13C and δ15N, suggesting that close relatives have similar physiological strategies. The signal of phylogeny was generally stronger than that of the local environment. However, within some specialized environments (e.g., wetlands, sandy soils), we found environmental effects and/or niche conservatism. Phylogenetic signal in δ13C appears to be most closely related to the constraints on metabolic demand and supply of C, and δ15N appears to be most strongly related to mycorrhizal associations within the family.

Research paper thumbnail of Diversity and abundance of litter-dwelling arthropods increase with time-since-burn in a Florida scrub ecosystem Diversity and abundance of litter-dwelling arthropods increase with time-since- burn in a Florida scrub ecosystem

Biodiversity, 2017

Fire is an important disturbance that can impact biodiversity and ecosystem functions. Although f... more Fire is an important disturbance that can impact biodiversity and ecosystem functions. Although fire impacts have been well studied in plants and some animals, the effects of fire on litter-dwelling arthropods remain poorly documented. I investigated the effect of time-since-burn on litter-dwelling arthropods in a Florida scrub ecosystem. I measured total arthropod richness and diversity as well as arachnid detritivore and predator abundance along a time-since-burn chronosequence. Arthropod richness and diversity and arachnid abundance significantly increased within 8 years post-burn. Arthropod richness and diversity and arachnid abundance did not differ between 8 and 89 years since last burn. These results demonstrate that litter-dwelling arthropods can quickly re-establish their community composition within 8 years after a burn, which may have important consequences for litter decomposition and nutrient cycling rates over successional time.

Research paper thumbnail of Predicting peatland carbon fluxes from non-destructive plant traits

Functional Ecology, 2017

Determining the plant traits that best predict carbon (C) storage is increasingly important as gl... more Determining the plant traits that best predict carbon (C) storage is increasingly important as global change drivers will affect plant species composition and ecosystem C cycling. Despite the critical role of peatlands in the global C cycle, trait-flux relationships in peatlands are relatively unknown.
We assessed the ability of four non-destructive plant traits to predict carbon dioxide (CO2) and methane (CH4) fluxes over two growing seasons in a temperate peatland in Ontario, Canada. We examined relationships between C-fluxes and leaf area, leaf persistence (deciduous, evergreen), growth form (woody, herbaceous), and aerenchyma tissue. To explore potential inconsistencies between different scales of data aggregation, traits were analysed at the level of plots, species and microsites.
CO2 fluxes showed a positive relationship with leaf area and leaf persistence, and a negative relationship with proportion of woody species. CH4 fluxes showed a positive relationship with aerenchyma and leaf area. The significance of trait-flux relationships differed based on whether data were averaged at the level of plot, species or microsite.
We recommend applying leaf area as a non-destructive trait to other systems where it is not ideal to measure traits destructively. A better understanding of the relationships between above and belowground traits is likely needed to further explain variation in ecosystem respiration and CH4 fluxes from plant traits.