☯ These authors contributed equally to this work. ‡ These authors are joint senior authors on thi... more ☯ These authors contributed equally to this work. ‡ These authors are joint senior authors on this work.
Despite claims that plantations both enhance and undermine the quality, valuation and protection ... more Despite claims that plantations both enhance and undermine the quality, valuation and protection of natural forests, plantation forestry continues to expand worldwide. In Paraguay, changes in environmental policy, extension practices, and public perception of eucalypts (Eucalyptus spp.) have promoted a boom in plantation production of these species over the last 20 years. Smallholders, faced with the dilemma of accelerating environmental degradation juxtaposed with persistent economic need, have widely adopted eucalypt forestry due to the quick growth, low establishment cost and high commercial value of eucalypt plantations. The consequences of this recent, rapid change for smallholder land management remain uncharacterized. Mixed methods analysis of a multiple-case study of 45 families was employed to describe the evolving ecological context of small-scale eucalypt forestry in Eastern Paraguay. This study suggests that eucalypts play a complex, potentially sustainable role in the study area. Producers have integrated agroforestry into eucalypt management and report replacing crop and cattle production with eucalypts in the mosaic of regional land-use. Eucalypts are also integral to participants’ views on reforestation of deforested land and fit ambiguously into their concepts of reforestation and species’ nativeness. Understanding the evolving role of eucalypts in Eastern Paraguay is of critical importance to policymakers and foresters promoting sustainable management.
Smallholder eucalyptus (Eucalyptus species) plantation forestry is common among rural farmers in ... more Smallholder eucalyptus (Eucalyptus species) plantation forestry is common among rural farmers in Eastern Paraguay. Yet there has been no systematic study of the silvicultural practices utilized by smallholder plantation owners in the region. In response, I conducted a case study of semi-structured interviews with 45 eucalyptus-owning smallholders. My study characterizes the households that have adopted eucalyptus forestry and the management of these plantations. Silvicultural practices varied among households and, for some parameters, among regions. Improved extension efforts could enable eucalyptus plantation owners in the study population to improve production both for commercial sale and domestic use.
Research highlights: The availability of global distribution data and new, fossil-calibrated phyl... more Research highlights: The availability of global distribution data and new, fossil-calibrated phylogenies has made it possible to compare the climatic niches of the temperate maple (Acer L.) taxa and assess phylogenetic and continental patterns in niche overlap. Background and Objectives: The maples have radiated from East Asia into two other temperate continental bioregions, North America and Eurasia (Europe and West Asia), over a roughly 60-million-year period. During this time, the Earth’s climate experienced pronounced cooling and drying, culminating in cyclic periods of widespread temperate glaciation in the Pliocene to Pleistocene. The objective of this study is to use newly available data to model the climatic niches of 60% of the temperate maples and assess patterns of niche divergence, constraint, and conservatism in the genus’s radiation out of East Asia. Materials and Methods: I assembled global occurrence data and associated climatic information for 71 maple taxa, includi...
Reflecting on the state of community ecology, John Lawton rendered a famously uncharitable verdic... more Reflecting on the state of community ecology, John Lawton rendered a famously uncharitable verdict. Community ecology ‘‘is a mess,’’ riddled with ‘‘so much contingency that useful generalisations are hard to find’’ (Lawton 1999, 178). Nearly two decades later, the field presents a similar aspect. Community ecology is ‘‘widely perceived as...a theoretical and conceptual bucket case,’’ Mark Vellend observes (42). Over the past century, its practitioners have devised literally hundreds of conceptual and theoretical models intended to explain patterns of diversity, abundance, and composition in ecological communities. However, because nearly all these models are ‘‘relevant to at least one type of community somewhere on earth, the list of explanations... only ever gets longer, never shorter’’ (2). Vellend’s new book, The Theory of Ecological Communities, sets out to reframe this tangle of models in a way that highlights linkages between various extant theoretical ideas. In it, he brings ...
Background A variety of basic and applied research programs in plant biology require the accurate... more Background A variety of basic and applied research programs in plant biology require the accurate and reliable determination of plant tissue cold hardiness. Over the past 50 years, the electrolyte leakage method has emerged as a popular and practical method for quantifying the amount of damage inflicted on plant tissue by exposure to freezing temperatures. Numerous approaches for carrying out this method and analyzing the resultant data have emerged. These include multiple systems for standardizing and modeling raw electrolyte leakage data and multiple protocols for boiling or autoclaving samples in order to maximize leakage as a positive control. We compare four different routines for standardization of leakage data and assess a novel control method—immersion in liquid nitrogen in lieu of traditional autoclaving—and apply them to woody twigs collected from 12 maple (Acer) species in early spring. We compare leakage data from these samples using each of four previously published for...
SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical,... more SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical, and architectural traits. We posit that the degree to which plants differentiate in n-dimensional spectral space is a measure of niche differentiation and reveals functional complementarity.In both experimentally and naturally assembled communities, we quantified plant niches using hypervolumes delineated by either plant spectra or 10 functional traits. We compared the niche fraction unique to each species in spectral and trait spaces with increasing dimensionality, and investigated the association between the spectral space occupied, plant growth and community productivity.We show that spectral niches differentiated species better than their functional trait niches. The amount of spectral space occupied by individuals and plant communities increased with plant growth and community productivity, respectively. Further, community productivity was better explained by inter-individual spect...
While the relationship between plant and microbial diversity has been well studied in grasslands,... more While the relationship between plant and microbial diversity has been well studied in grasslands, less is known about similar relationships in forests, especially for obligately symbiotic arbuscular mycorrhizal (AM) fungi. To assess the effect of varying tree diversity on microbial alpha- and beta-diversity, we sampled soil from plots in a high-density tree diversity experiment in Minnesota, USA three years after establishment. Three of 12 tree species are AM hosts; the other nine primarily associate with ectomycorrhizal fungi. We used phospho- and neutral lipid fatty acid analysis to characterize the biomass and functional identity of the whole soil bacterial and fungal community and high throughput sequencing to identify the species-level richness and composition of the AM fungal community. We found that plots of differing tree composition had different bacterial and fungal communities; plots with conifers, and especially Juniperus virginiana, had lower densities of several bacter...
Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to... more Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to morphological differences from nearby remnant populations. Pleistocene hybridization between and has been proposed, but the nearest populations are currently several hundred kilometers east. We tested the hybrid-origin hypothesis using genetic data and characterized putative hybrids phenotypically. We compared nuclear microsatellite loci and chloroplast sequences of Niobrara River aspens to their putative parental species. Parental species and putative hybrids were also grown in a common garden for phenotypic comparison. On the common garden plants, we measured leaf morphological traits and leaf-level spectral reflectance profiles, from which chemical traits were derived. The genetic composition of the three unique Niobrara aspen genotypes is consistent with the hybridization hypothesis and with maternal chloroplast inheritance from . Leaf margin dentition and abaxial pubescence differe...
Over the last two decades, empirical work has established that higher biodiversity can lead to gr... more Over the last two decades, empirical work has established that higher biodiversity can lead to greater primary productivity; however, the importance of different aspects of biodiversity in contributing to such relationships is rarely elucidated. We assessed the relative importance of species richness, phylogenetic diversity, functional diversity, and identity of neighbors for stem growth three years after seedling establishment in a tree diversity experiment in eastern Minnesota. Generally, we found that community-weighted means of key functional traits (including mycorrhizal association, leaf nitrogen and calcium, and waterlogging tolerance) as well as species richness were strong, independent predictors of stem biomass growth. More phylogenetically diverse communities did not consistently produce more biomass than expected, and the trait values or diversity of individual functional traits better predicted biomass production than did a multidimensional functional diversity metric. ...
SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical,... more SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical, and architectural traits. We posit that the degree to which plants differentiate in n-dimensional spectral space is a measure of niche differentiation and reveals functional complementarity.In both experimentally and naturally assembled communities, we quantified plant niches using hypervolumes delineated by either plant spectra or 10 functional traits. We compared the niche fraction unique to each species in spectral and trait spaces with increasing dimensionality, and investigated the association between the spectral space occupied, plant growth and community productivity.We show that spectral niches differentiated species better than their functional trait niches. The amount of spectral space occupied by individuals and plant communities increased with plant growth and community productivity, respectively. Further, community productivity was better explained by inter-individual spect...
☯ These authors contributed equally to this work. ‡ These authors are joint senior authors on thi... more ☯ These authors contributed equally to this work. ‡ These authors are joint senior authors on this work.
Despite claims that plantations both enhance and undermine the quality, valuation and protection ... more Despite claims that plantations both enhance and undermine the quality, valuation and protection of natural forests, plantation forestry continues to expand worldwide. In Paraguay, changes in environmental policy, extension practices, and public perception of eucalypts (Eucalyptus spp.) have promoted a boom in plantation production of these species over the last 20 years. Smallholders, faced with the dilemma of accelerating environmental degradation juxtaposed with persistent economic need, have widely adopted eucalypt forestry due to the quick growth, low establishment cost and high commercial value of eucalypt plantations. The consequences of this recent, rapid change for smallholder land management remain uncharacterized. Mixed methods analysis of a multiple-case study of 45 families was employed to describe the evolving ecological context of small-scale eucalypt forestry in Eastern Paraguay. This study suggests that eucalypts play a complex, potentially sustainable role in the study area. Producers have integrated agroforestry into eucalypt management and report replacing crop and cattle production with eucalypts in the mosaic of regional land-use. Eucalypts are also integral to participants’ views on reforestation of deforested land and fit ambiguously into their concepts of reforestation and species’ nativeness. Understanding the evolving role of eucalypts in Eastern Paraguay is of critical importance to policymakers and foresters promoting sustainable management.
Smallholder eucalyptus (Eucalyptus species) plantation forestry is common among rural farmers in ... more Smallholder eucalyptus (Eucalyptus species) plantation forestry is common among rural farmers in Eastern Paraguay. Yet there has been no systematic study of the silvicultural practices utilized by smallholder plantation owners in the region. In response, I conducted a case study of semi-structured interviews with 45 eucalyptus-owning smallholders. My study characterizes the households that have adopted eucalyptus forestry and the management of these plantations. Silvicultural practices varied among households and, for some parameters, among regions. Improved extension efforts could enable eucalyptus plantation owners in the study population to improve production both for commercial sale and domestic use.
Research highlights: The availability of global distribution data and new, fossil-calibrated phyl... more Research highlights: The availability of global distribution data and new, fossil-calibrated phylogenies has made it possible to compare the climatic niches of the temperate maple (Acer L.) taxa and assess phylogenetic and continental patterns in niche overlap. Background and Objectives: The maples have radiated from East Asia into two other temperate continental bioregions, North America and Eurasia (Europe and West Asia), over a roughly 60-million-year period. During this time, the Earth’s climate experienced pronounced cooling and drying, culminating in cyclic periods of widespread temperate glaciation in the Pliocene to Pleistocene. The objective of this study is to use newly available data to model the climatic niches of 60% of the temperate maples and assess patterns of niche divergence, constraint, and conservatism in the genus’s radiation out of East Asia. Materials and Methods: I assembled global occurrence data and associated climatic information for 71 maple taxa, includi...
Reflecting on the state of community ecology, John Lawton rendered a famously uncharitable verdic... more Reflecting on the state of community ecology, John Lawton rendered a famously uncharitable verdict. Community ecology ‘‘is a mess,’’ riddled with ‘‘so much contingency that useful generalisations are hard to find’’ (Lawton 1999, 178). Nearly two decades later, the field presents a similar aspect. Community ecology is ‘‘widely perceived as...a theoretical and conceptual bucket case,’’ Mark Vellend observes (42). Over the past century, its practitioners have devised literally hundreds of conceptual and theoretical models intended to explain patterns of diversity, abundance, and composition in ecological communities. However, because nearly all these models are ‘‘relevant to at least one type of community somewhere on earth, the list of explanations... only ever gets longer, never shorter’’ (2). Vellend’s new book, The Theory of Ecological Communities, sets out to reframe this tangle of models in a way that highlights linkages between various extant theoretical ideas. In it, he brings ...
Background A variety of basic and applied research programs in plant biology require the accurate... more Background A variety of basic and applied research programs in plant biology require the accurate and reliable determination of plant tissue cold hardiness. Over the past 50 years, the electrolyte leakage method has emerged as a popular and practical method for quantifying the amount of damage inflicted on plant tissue by exposure to freezing temperatures. Numerous approaches for carrying out this method and analyzing the resultant data have emerged. These include multiple systems for standardizing and modeling raw electrolyte leakage data and multiple protocols for boiling or autoclaving samples in order to maximize leakage as a positive control. We compare four different routines for standardization of leakage data and assess a novel control method—immersion in liquid nitrogen in lieu of traditional autoclaving—and apply them to woody twigs collected from 12 maple (Acer) species in early spring. We compare leakage data from these samples using each of four previously published for...
SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical,... more SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical, and architectural traits. We posit that the degree to which plants differentiate in n-dimensional spectral space is a measure of niche differentiation and reveals functional complementarity.In both experimentally and naturally assembled communities, we quantified plant niches using hypervolumes delineated by either plant spectra or 10 functional traits. We compared the niche fraction unique to each species in spectral and trait spaces with increasing dimensionality, and investigated the association between the spectral space occupied, plant growth and community productivity.We show that spectral niches differentiated species better than their functional trait niches. The amount of spectral space occupied by individuals and plant communities increased with plant growth and community productivity, respectively. Further, community productivity was better explained by inter-individual spect...
While the relationship between plant and microbial diversity has been well studied in grasslands,... more While the relationship between plant and microbial diversity has been well studied in grasslands, less is known about similar relationships in forests, especially for obligately symbiotic arbuscular mycorrhizal (AM) fungi. To assess the effect of varying tree diversity on microbial alpha- and beta-diversity, we sampled soil from plots in a high-density tree diversity experiment in Minnesota, USA three years after establishment. Three of 12 tree species are AM hosts; the other nine primarily associate with ectomycorrhizal fungi. We used phospho- and neutral lipid fatty acid analysis to characterize the biomass and functional identity of the whole soil bacterial and fungal community and high throughput sequencing to identify the species-level richness and composition of the AM fungal community. We found that plots of differing tree composition had different bacterial and fungal communities; plots with conifers, and especially Juniperus virginiana, had lower densities of several bacter...
Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to... more Aspen groves along the Niobrara River in Nebraska have long been a biogeographic curiosity due to morphological differences from nearby remnant populations. Pleistocene hybridization between and has been proposed, but the nearest populations are currently several hundred kilometers east. We tested the hybrid-origin hypothesis using genetic data and characterized putative hybrids phenotypically. We compared nuclear microsatellite loci and chloroplast sequences of Niobrara River aspens to their putative parental species. Parental species and putative hybrids were also grown in a common garden for phenotypic comparison. On the common garden plants, we measured leaf morphological traits and leaf-level spectral reflectance profiles, from which chemical traits were derived. The genetic composition of the three unique Niobrara aspen genotypes is consistent with the hybridization hypothesis and with maternal chloroplast inheritance from . Leaf margin dentition and abaxial pubescence differe...
Over the last two decades, empirical work has established that higher biodiversity can lead to gr... more Over the last two decades, empirical work has established that higher biodiversity can lead to greater primary productivity; however, the importance of different aspects of biodiversity in contributing to such relationships is rarely elucidated. We assessed the relative importance of species richness, phylogenetic diversity, functional diversity, and identity of neighbors for stem growth three years after seedling establishment in a tree diversity experiment in eastern Minnesota. Generally, we found that community-weighted means of key functional traits (including mycorrhizal association, leaf nitrogen and calcium, and waterlogging tolerance) as well as species richness were strong, independent predictors of stem biomass growth. More phylogenetically diverse communities did not consistently produce more biomass than expected, and the trait values or diversity of individual functional traits better predicted biomass production than did a multidimensional functional diversity metric. ...
SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical,... more SummaryPlants’ spectra provide integrative measures of their chemical, morphological, anatomical, and architectural traits. We posit that the degree to which plants differentiate in n-dimensional spectral space is a measure of niche differentiation and reveals functional complementarity.In both experimentally and naturally assembled communities, we quantified plant niches using hypervolumes delineated by either plant spectra or 10 functional traits. We compared the niche fraction unique to each species in spectral and trait spaces with increasing dimensionality, and investigated the association between the spectral space occupied, plant growth and community productivity.We show that spectral niches differentiated species better than their functional trait niches. The amount of spectral space occupied by individuals and plant communities increased with plant growth and community productivity, respectively. Further, community productivity was better explained by inter-individual spect...
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