Scholars@Duke
William F. Morris

William F. Morris

Professor of Biology
Biology
wfmorris@duke.edu
Duke Box 90325, Durham, NC 27708-0325
104 Bio Sci Bldg, Durham, NC 27708

Selected Publications

Vital rate responses to temperature lead to butterfly population declines under future warming scenarios

Journal Article Journal of Insect Conservation · October 1, 2024 Due to their dependence on environmental temperatures, ectothermic animals are likely to be particularly sensitive to global climate change. Accurate prediction of ectotherm population responses to climate change requires a mechanistic understanding of eff ... Full text Cite

Inclusive Fitness May Explain Some but Not All Benefits Derived from Helping Behavior in a Cooperatively Breeding Bird.

Journal Article The American naturalist · March 2024 AbstractIn cooperative breeding systems, inclusive fitness theory predicts that nonbreeding helpers more closely related to the breeders should be more willing to provide costly alloparental care and thus have more impact on breeder fitness. In the red-coc ... Full text Cite

Nonlinear life table response experiment analysis: Decomposing nonlinear and nonadditive population growth responses to changes in environmental drivers.

Journal Article Ecology letters · March 2024 Life table response experiments (LTREs) decompose differences in population growth rate between environments into separate contributions from each underlying demographic rate. However, most LTRE analyses make the unrealistic assumption that the relationshi ... Full text Cite

Restoration success varies based on time since restoration in a disturbance-dependent ephemeral wetland ecosystem

Journal Article Restoration Ecology · July 1, 2023 Habitat restoration frequently focuses on reaching an idealized steady state, but this is unrealistic for disturbance-dependent ecosystems where temporal variability is inherent and habitat conditions are expected to fluctuate. Understanding the ways in wh ... Full text Cite

Conflicting constraints on male mating success shape reward size in pollen-rewarding plants.

Journal Article American journal of botany · June 2023 PremisePollen-rewarding plants face two conflicting constraints: They must prevent consumptive emasculation while remaining attractive to pollen-collecting visitors. Small pollen packages (the quantity of pollen available in a single visit) may di ... Full text Cite

Seed type and origin-dependent seedling emergence patterns in Danthonia californica, a species commonly used in grassland restoration.

Journal Article Plant-environment interactions (Hoboken, N.J.) · April 2023 Danthonia californica Bolander (Poaceae)is a native perennial bunchgrass commonly used in the restoration of prairie ecosystems in the western United States. Plants of this species simultaneously produce both chasmogamous (potentially outcrossed) an ... Full text Cite

Shifting precipitation regimes alter the phenology and population dynamics of low latitude ectotherms

Journal Article Climate Change Ecology · December 1, 2022 Predicting how species respond to changes in climate is critical to conserving biodiversity. Modeling efforts to date have largely centered on predicting the effects of warming temperatures on temperate species phenology. In and near the tropics, the effec ... Full text Cite

Climate change weakens the impact of disturbance interval on the growth rate of natural populations of Venus flytrap

Journal Article Ecological Monographs · November 1, 2022 Disturbances elicit both positive and negative effects on organisms; these effects vary in their strength and their timing. Effects of disturbance interval (i.e., the length of time between disturbances) on population growth will depend on both the timing ... Full text Cite

Are genetic variation and demographic performance linked?

Journal Article Evolutionary applications · November 2022 Quantifying relationships between genetic variation and population viability is important from both basic biological and applied conservation perspectives, yet few populations have been monitored with both long-term demographic and population genetics appr ... Full text Cite

Climate warming threatens the persistence of a community of disturbance-adapted native annual plants.

Journal Article Ecology · October 2021 With ongoing climate change, populations are expected to exhibit shifts in demographic performance that will alter where a species can persist. This presents unique challenges for managing plant populations and may require ongoing interventions, including ... Full text Cite

Shifting correlations among multiple aspects of weather complicate predicting future demography of a threatened species

Journal Article Ecosphere · September 1, 2021 Most studies of the ecological effects of climate change consider only a limited number of weather drivers that could affect populations, though we know that multiple weather drivers can simultaneously affect population growth rate. Multiple drivers could ... Full text Cite

A critical comparison of integral projection and matrix projection models for demographic analysis

Journal Article Ecological Monographs · May 1, 2021 Featured Publication Structured demographic models are among the most common and useful tools in population biology. However, the introduction of integral projection models (IPMs) has caused a profound shift in the way many demographic models are conceptualized. Some researche ... Full text Cite

Latitudinal gradients in population growth do not reflect demographic responses to climate.

Journal Article Ecological applications : a publication of the Ecological Society of America · March 2021 Featured Publication Spatial gradients in population growth, such as across latitudinal or elevational gradients, are often assumed to primarily be driven by variation in climate, and are frequently used to infer species' responses to climate change. Here, we use a novel demog ... Full text Cite

Climate manipulations differentially affect plant population dynamics within versus beyond northern range limits

Journal Article Journal of Ecology · February 1, 2021 Featured Publication Predicting species' range shifts under future climate is a central goal of conservation ecology. Studying populations within and beyond multiple species' current ranges can help identify whether demographic responses to climate change exhibit directionalit ... Full text Cite

Climate change impacts on population growth across a species' range differ due to nonlinear responses of populations to climate and variation in rates of climate change.

Journal Article PloS one · January 2021 Impacts of climate change can differ substantially across species' geographic ranges, and impacts on a given population can be difficult to predict accurately. A commonly used approximation for the impacts of climate change on the population growth rate is ... Full text Cite

Correction for Morris et al., Biotic and anthropogenic forces rival climatic/abiotic factors in determining global plant population growth and fitness.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · March 2020 Full text Cite

Biotic and anthropogenic forces rival climatic/abiotic factors in determining global plant population growth and fitness.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · January 2020 Multiple, simultaneous environmental changes, in climatic/abiotic factors, interacting species, and direct human influences, are impacting natural populations and thus biodiversity, ecosystem services, and evolutionary trajectories. Determining whether the ... Full text Cite

Improving structured population models with more realistic representations of non-normal growth

Journal Article Methods in Ecology and Evolution · September 1, 2019 Structured population models are among the most widely used tools in ecology and evolution. Integral projection models (IPMs) use continuous representations of how survival, reproduction and growth change as functions of state variables such as size, requi ... Full text Cite

Asynchrony in individual and subpopulation fecundity stabilizes reproductive output of an alpine plant population.

Journal Article Ecology · April 2019 Population-wide outcomes such as abundance, reproductive output, or mean survival can be stabilized by non-synchronous variation in the performance of individuals or subpopulations. Such "portfolio effects" have been increasingly documented at the scale of ... Full text Cite

Incorporating local adaptation into forecasts of species' distribution and abundance under climate change.

Journal Article Global change biology · March 2019 Populations of many species are genetically adapted to local historical climate conditions. Yet most forecasts of species' distributions under climate change have ignored local adaptation (LA), which may paint a false picture of how species will respond ac ... Full text Cite

Geographic location, local environment, and individual size mediate the effects of climate warming and neighbors on a benefactor plant.

Journal Article Oecologia · January 2019 Predictions of plant responses to global warming frequently ignore biotic interactions and intraspecific variation across geographical ranges. Benefactor species play an important role in plant communities by protecting other taxa from harsh environments, ... Full text Cite

Both life-history plasticity and local adaptation will shape range-wide responses to climate warming in the tundra plant Silene acaulis.

Journal Article Global change biology · April 2018 Many predictions of how climate change will impact biodiversity have focused on range shifts using species-wide climate tolerances, an approach that ignores the demographic mechanisms that enable species to attain broad geographic distributions. But these ... Full text Cite

Mechanism matters: the cause of fluctuations in boom-bust populations governs optimal habitat restoration strategy.

Journal Article Ecological applications : a publication of the Ecological Society of America · March 2018 Many populations exhibit boom-bust dynamics in which abundance fluctuates dramatically over time. Past research has focused on identifying whether the cause of fluctuations is primarily exogenous, e.g., environmental stochasticity coupled with weak density ... Full text Cite

Environmental stress effects on reproduction and sexual dimorphism in the gynodioecious species Silene acaulis

Journal Article Environmental and Experimental Botany · February 1, 2018 In gynodioecious species, hermaphrodite plants invest both in seed and pollen production, whereas female plants only produce fruits. For both sexes to coexist, such unbalanced investment is expected to translate in some kind of reproductive compensation, p ... Full text Cite

Aridity weakens population-level effects of multiple species interactions on Hibiscus meyeri.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · January 2018 Predicting how species' abundances and ranges will shift in response to climate change requires a mechanistic understanding of how multiple factors interact to limit population growth. Both abiotic stress and species interactions can limit populations and ... Full text Cite

Does climate variability influence the demography of wild primates? Evidence from long-term life-history data in seven species.

Journal Article Global change biology · November 2017 Earth's rapidly changing climate creates a growing need to understand how demographic processes in natural populations are affected by climate variability, particularly among organisms threatened by extinction. Long-term, large-scale, and cross-taxon studi ... Full text Cite

How effective are buffer zones in managing invasive beavers in Patagonia? A simulation study

Journal Article Biodiversity and Conservation · October 1, 2017 In an age of invasions, it is critical to design and test management strategies to more efficiently control foreign species. Spatially explicit individual based models (SEIBMs) are a powerful tool to explore different management scenarios to control invade ... Full text Cite

Ecological and evolutionary impacts of changing climatic variability.

Journal Article Biological reviews of the Cambridge Philosophical Society · February 2017 While average temperature is likely to increase in most locations on Earth, many places will simultaneously experience higher variability in temperature, precipitation, and other climate variables. Although ecologists and evolutionary biologists widely rec ... Full text Cite

Habitat restoration alters adult butterfly morphology and potential fecundity through effects on host plant quality

Journal Article Ecosphere · November 1, 2016 Conservation strategies for threatened species frequently include habitat restoration, but the success of such recovery efforts has been mixed. When the target is an insect herbivore, restoration efforts have traditionally attempted to increase the abundan ... Full text Cite

Demography and population growth rate of the tree Prosopis flexuosa with contrasting grazing regimes in the Central Monte Desert

Journal Article Forest Ecology and Management · June 1, 2016 One of the most important current challenges for ecologists is to evaluate how human-induced changes in ecosystems would impact viability of populations. Demographic response to anthropogenic impact could help us to understand how to manage those impacts. ... Full text Cite

Female and male life tables for seven wild primate species.

Journal Article Scientific data · March 2016 We provide male and female census count data, age-specific survivorship, and female age-specific fertility estimates for populations of seven wild primates that have been continuously monitored for at least 29 years: sifaka (Propithecus verreauxi) in Madag ... Full text Cite

Advancing environmentally explicit structured population models of plants

Journal Article Journal of Ecology · March 1, 2016 The relationship between the performance of individuals and the surrounding environment is fundamental in ecology and evolutionary biology. Assessing how abiotic and biotic environmental factors influence demographic processes is necessary to understand an ... Full text Cite

Demographic compensation among populations: what is it, how does it arise and what are its implications?

Journal Article Ecology letters · November 2015 Most species are exposed to significant environmental gradients across their ranges, but vital rates (survival, growth, reproduction and recruitment) need not respond in the same direction to those gradients. Opposing vital rate trends across environments, ... Full text Cite

The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth.

Journal Article Oecologia · October 2015 The impact of mutualists on a partner's demography depends on how they affect the partner's multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or inte ... Full text Cite

Habitat restoration affects immature stages of a wetland butterfly through indirect effects on predation.

Journal Article Ecology · July 2015 Habitat loss worldwide has led to the widespread use of restoration practices for the recovery of imperiled species. However, recovery success may be hampered by focusing on plant communities, rather than the complex suite of direct and indirect interactio ... Full text Cite

Do geographic, climatic or historical ranges differentiate the performance of central versus peripheral populations?

Journal Article Global Ecology and Biogeography · June 1, 2015 Aim: The 'centre-periphery hypothesis' (CPH) predicts that species performance (genetics, physiology, morphology, demography) will decline gradually from the centre towards the periphery of the geographic range. This hypothesis has been subjected to contin ... Full text Cite

Predicting changes in the distribution and abundance of species under environmental change.

Journal Article Ecology letters · March 2015 Environmental changes are expected to alter both the distribution and the abundance of organisms. A disproportionate amount of past work has focused on distribution only, either documenting historical range shifts or predicting future occurrence patterns. ... Full text Cite

Predicting changes in the distribution and abundance of species under environmental change

Journal Article Ecology Letters · March 1, 2015 Environmental changes are expected to alter both the distribution and the abundance of organisms. A disproportionate amount of past work has focused on distribution only, either documenting historical range shifts or predicting future occurrence patterns. ... Full text Cite

Recommendations for improving recovery criteria under the US Endangered Species Act

Journal Article BioScience · January 28, 2015 Recovery criteria, the thresholds mandated by the Endangered Species Act that define when species may be considered for downlisting or removal from the endangered species list, are a key component of conservation planning in the United States. We recommend ... Full text Cite

Defining and evaluating the umbrella species concept for conserving and restoring landscape connectivity.

Journal Article Conservation biology : the journal of the Society for Conservation Biology · December 2014 Conserving or restoring landscape connectivity between patches of breeding habitat is a common strategy to protect threatened species from habitat fragmentation. By managing connectivity for some species, usually charismatic vertebrates, it is often assume ... Full text Cite

Ability of matrix models to explain the past and predict the future of plant populations.

Journal Article Conservation biology : the journal of the Society for Conservation Biology · October 2013 Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynam ... Full text Cite

Reproductive aging patterns in primates reveal that humans are distinct.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · August 2013 Women rarely give birth after ∼45 y of age, and they experience the cessation of reproductive cycles, menopause, at ∼50 y of age after a fertility decline lasting almost two decades. Such reproductive senescence in mid-lifespan is an evolutionary puzzle of ... Full text Cite

Variation in stochastic demography between and within central and peripheral regions in a widespread short-lived herb.

Journal Article Ecology · June 2013 Analyzing intraspecific variation in population dynamics in relation to environmental factors is crucial to understand the current and future distributions of plant species. Across ranges, peripheral populations are often expected to show lower and more te ... Full text Cite

Empirical estimation of dispersal resistance surfaces: A case study with red-cockaded woodpeckers

Journal Article Landscape Ecology · April 1, 2013 Persistence of wildlife populations depends on the degree to which landscape features facilitate animal movements between isolated habitat patches. Due to limited data availability, the effect of landscape features on animal dispersal is typically estimate ... Full text Cite

How complex do models need to be to predict dispersal of threatened species through matrix habitats?

Journal Article Ecological applications : a publication of the Ecological Society of America · July 2012 Persistence of species in fragmented landscapes depends on dispersal among suitable breeding sites, and dispersal is often influenced by the "matrix" habitats that lie between breeding sites. However, measuring effects of different matrix habitats on movem ... Full text Cite

The geography of demography: long-term demographic studies and species distribution models reveal a species border limited by adaptation.

Journal Article The American naturalist · October 2011 Potential causes of species' geographic distribution limits fall into two broad classes: (1) limited adaptation across spatially variable environments and (2) limited opportunities to colonize unoccupied areas. Combining demographic studies, analyses of de ... Full text Cite

Higher survival at low density counteracts lower fecundity to obviate Allee effects in a perennial plant

Journal Article Journal of Ecology · September 1, 2011 1.At low densities, plants may produce fewer seeds than at high densities, due to reduced pollinator visits or reduced receipt of compatible pollen. In principle, lower seed production could lead to an Allee effect (a decline in the population growth rate ... Full text Cite

Aging in the natural world: comparative data reveal similar mortality patterns across primates.

Journal Article Science (New York, N.Y.) · March 2011 Human senescence patterns-late onset of mortality increase, slow mortality acceleration, and exceptional longevity-are often described as unique in the animal world. Using an individual-based data set from longitudinal studies of wild populations of seven ... Full text Cite

How do plant ecologists use matrix population models?

Journal Article Ecology letters · January 2011 Matrix projection models are among the most widely used tools in plant ecology. However, the way in which plant ecologists use and interpret these models differs from the way in which they are presented in the broader academic literature. In contrast to ca ... Full text Cite

Low demographic variability in wild primate populations: fitness impacts of variation, covariation, and serial correlation in vital rates.

Journal Article The American naturalist · January 2011 In a stochastic environment, long-term fitness can be influenced by variation, covariation, and serial correlation in vital rates (survival and fertility). Yet no study of an animal population has parsed the contributions of these three aspects of variabil ... Full text Open Access Cite

Demographic compensation and tipping points in climate-induced range shifts.

Journal Article Nature · October 2010 To persist, species are expected to shift their geographical ranges polewards or to higher elevations as the Earth's climate warms. However, although many species' ranges have shifted in historical times, many others have not, or have shifted only at the h ... Full text Cite

The Primate Life History Database: A unique shared ecological data resource.

Journal Article Methods in ecology and evolution · June 2010 The importance of data archiving, data sharing, and public access to data has received considerable attention. Awareness is growing among scientists that collaborative databases can facilitate these activities.We provide a detailed description of the colla ... Full text Cite

Benefit and cost curves for typical pollination mutualisms.

Journal Article Ecology · May 2010 Mutualisms provide benefits to interacting species, but they also involve costs. If costs come to exceed benefits as population density or the frequency of encounters between species increases, the interaction will no longer be mutualistic. Thus curves tha ... Full text Cite

The conflicting role of matrix habitats as conduits and barriers for dispersal.

Journal Article Ecology · April 2010 Determining connectivity within complex landscapes is difficult if habitats that facilitate dispersal differ from habitats where animals normally are found or enter. We addressed the question of how landscape features affect dispersal by quantifying two cr ... Full text Cite

For ant-protected plants, the best defense is a hungry offense.

Journal Article Ecology · October 2009 Animal foraging has been characterized as an attempt to maximize the intake of carbon and nitrogen at appropriate ratios. Plant species in over 90 families produce carbohydrate-rich extrafloral nectar (EFN), a resource attractive to ants and other omnivoro ... Full text Cite

Allee dynamics generated by protection mutualisms can drive oscillations in trophic cascades

Journal Article Theoretical Ecology · June 1, 2008 Understanding the relative effect of top predators and primary producers on intermediate trophic levels is a key question in ecology. Most previous work, however, has not considered either realistic nonlinearities in feedback between trophic levels or the ... Full text Cite

Simultaneous effects of food limitation and inducible resistance on herbivore population dynamics.

Journal Article Theoretical population biology · February 2008 Many herbivore populations fluctuate temporally, but the causes of those fluctuations remain unclear. Plant inducible resistance can theoretically cause herbivore population fluctuations, because herbivory may induce plant changes that reduce the survival ... Full text Cite

Longevity can buffer plant and animal populations against changing climatic variability.

Journal Article Ecology · January 2008 Both means and year-to-year variances of climate variables such as temperature and precipitation are predicted to change. However, the potential impact of changing climatic variability on the fate of populations has been largely unexamined. We analyzed mul ... Full text Cite

Direct and interactive effects of enemies and mutualists on plant performance: a meta-analysis.

Journal Article Ecology · April 2007 Plants engage in multiple, simultaneous interactions with other species; some (enemies) reduce and others (mutualists) enhance plant performance. Moreover, effects of different species may not be independent of one another; for example, enemies may compete ... Full text Cite

Sensitivity of the population growth rate to demographic variability within and between phases of the disturbance cycle.

Journal Article Ecology letters · December 2006 For species in disturbance-prone ecosystems, vital rates (survival, growth and reproduction) often vary both between and within phases of the cycle of disturbance and recovery; some of this variation is imposed by the environment, but some may represent ad ... Full text Cite

CO2-enrichment and nutrient availability alter ectomycorrhizal fungal communities.

Journal Article Ecology · September 2006 Ectomycorrhizal fungi (EMF), a phylogenetically and physiologically diverse guild, form symbiotic associations with many trees and greatly enhance their uptake of nutrients and water. Elevated CO2, which increases plant carbon supply and demand for mineral ... Full text Cite

Biotic interactions and plant invasions.

Journal Article Ecology letters · June 2006 Introduced plant populations lose interactions with enemies, mutualists and competitors from their native ranges, and gain interactions with new species, under new abiotic conditions. From a biogeographical perspective, differences in the assemblage of int ... Full text Cite

Integrating quality and quantity of mutualistic service to contrast ant species protecting Ferocactus wislizeni.

Journal Article Ecology · April 2006 Generalized, facultative mutualisms are often characterized by great variation in the benefits provided by different partner species. This variation may be due to differences among species in the quality and quantity of their interactions, as well as their ... Full text Cite

Demography in an increasingly variable world.

Journal Article Trends in ecology & evolution · March 2006 Recent advances in stochastic demography provide unique insights into the probable effects of increasing environmental variability on population dynamics, and these insights can be substantially different compared with those from deterministic models. Stoc ... Full text Cite

Modeling vital rates improves estimation of population projection matrices

Journal Article Population Ecology · January 1, 2006 Population projection matrices are commonly used by ecologists and managers to analyze the dynamics of stage-structured populations. Building projection matrices from data requires estimating transition rates among stages, a task that often entails estimat ... Full text Cite

On testing for a tradeoff between constitutive and induced resistance

Journal Article Oikos · January 1, 2006 Plants possess two types of resistance against herbivores: ever-present constitutive resistance and induced resistance triggered by attack. As the production of both resistance types entails a metabolic cost, a tradeoff between them has frequently been hyp ... Full text Cite

Environmental forcing and the competitive dynamics of a guild of cactus-tending ant mutualists

Journal Article Ecology · December 1, 2005 In generalized, multispecies mutualisms, competition among members of one guild can influence the net benefits that each species in the other guild receives. Hence seasonal factors that affect the dynamics of competition can also affect net benefits, espec ... Full text Cite

Interaction frequency as a surrogate for the total effect of animal mutualists on plants

Journal Article Ecology Letters · October 1, 2005 We evaluate whether species interaction frequency can be used as a surrogate for the total effect of a species on another. Because interaction frequency is easier to estimate than per-interaction effect, using interaction frequency as a surrogate of total ... Full text Cite

Correctly estimating how environmental stochasticity influences fitness and population growth.

Journal Article The American naturalist · July 2005 Increased temporal variance in life-history traits is generally predicted to decrease individual fitness and population growth. We show that a widely used result of stochastic sensitivity analysis that bolsters this generality is flawed because it ignores ... Full text Cite

How general are the determinants of the stochastic population growth rate across nearby sites?

Journal Article Ecological Monographs · January 1, 2005 A key question in both life history evolution and conservation biology is how much the contributions of different demographic processes to the rate of population growth vary from place to place. Using data from a six-year demographic study of five nearby p ... Full text Cite

Understanding and predicting the effects of sparse data on demographic analyses

Journal Article Ecology · January 1, 2005 Demographic models are an increasingly important tool in population biology. However, these models, especially stochastic matrix models, are based upon a multitude of parameters that must usually be estimated with only a few years of data and limited sampl ... Full text Cite

Buffering of life histories against environmental stochasticity: accounting for a spurious correlation between the variabilities of vital rates and their contributions to fitness.

Journal Article The American naturalist · April 2004 Life-history theory predicts vital rates that on average make large contributions to the annual multiplication rate of a lineage should be highly buffered against environmental variability. This prediction has been tested by looking for a negative correlat ... Full text Cite

When can two plant species facilitate each other's pollination?

Journal Article Oikos · April 1, 2004 Facilitation occurs when an increase in the density of one species causes an increase in the population growth rate or the density of a second species. In plants, ample evidence demonstrates that one species can facilitate another by ameliorating abiotic c ... Full text Cite

Conservation genetics in the recovery of endangered animal species: A review of US endangered species recovery plans (1977-1998)

Journal Article Animal Biodiversity and Conservation · December 1, 2003 The utility of genetic data in conservation efforts, particularly in comparison to demographic information, is the subject of ongoing debate. Using a database of information surveyed from 181 US endangered and threatened species recovery plans, we addresse ... Cite

Ecological dynamics of mutualist/antagonist communities.

Journal Article The American naturalist · October 2003 One approach to understanding how mutualisms function in community settings is to model well-studied pairwise interactions in the presence of the few species with which they interact most strongly. In nature, such species are often specialized antagonists ... Full text Cite

Coexistence of mutualists and exploiters on spatial landscapes

Journal Article Ecological Monographs · August 1, 2003 Mutualisms are almost ubiquitously exploited by species that gain the benefits that mutualists offer to each other, but that offer nothing in return. This paper investigates the possible dynamical outcomes of a mechanistically formulated model system, invo ... Full text Cite

Three-way coexistence in obligate mutualist-exploiter interactions: the potential role of competition.

Journal Article The American naturalist · June 2003 Many mutualisms host "exploiter" species that consume the benefits provided by one or both mutualists without reciprocating. Exploiters have been widely assumed to destabilize mutualisms, yet they are common. We develop models to explore conditions for loc ... Full text Cite

Conservation genetics in the recovery of endangered animal species: A review of US endangered species recovery plans (1977-1998)

Journal Article Animal Biodiversity and Conservation · 2003 The utility of genetic data in conservation efforts, particularly in comparison to demographic information, is the subject of ongoing debate. Using a database of information surveyed from 181 US endangered and threatened species recovery plans, we addresse ... Cite

The influence of the academic conservation biology literature on endangered species recovery planning

Journal Article Conservation Ecology · December 2002 Despite the volume of the academic conservation biology literature, there is little evidence as to what effect this work is having on endangered species recovery efforts. Using data collected from a national review of 136 endangered and threatened species ... Cite

Population viability analysis in endangered species recovery plans: Past use and future improvements

Journal Article Ecological Applications · January 1, 2002 Using the results of a survey of recovery plans for threatened and endangered species, we evaluated the role that Population Viability Analysis (PVA) has played in recovery planning and management of rare species in the United States. Although there was a ... Full text Cite

The influence of the academic conservation biology literature on endangered species recovery planning

Journal Article Ecology and Society · January 1, 2002 Despite the volume of the academic conservation biology literature, there is little evidence as to what effect this work is having on endangered species recovery efforts. Using data collected from a national review of 136 endangered and threatened species ... Full text Cite

Induced resistance to Mexican bean beetles in soybean: Variation among genotypes and lack of correlation with constitutive resistance

Journal Article Oecologia · January 1, 2000 Fourteen genotypes (varieties) of soybean (Glycine max) were screened for levels of induced resistance to Mexican bean beetle (Epilachna varivestis) damage, and a subset of 6 of those varieties was screened for levels of constitutive resistance to Mexican ... Full text Cite

Detecting population-level consequences of ongoing environmental change without long-term monitoring

Journal Article Ecology · January 1, 1999 The frequent lack of correspondence between measured population stage structures and those predicted from demographic models has usually been seen as an embarrassment, resulting from poor data, or a testimony to the failings of overly simplistic models. Ho ... Full text Cite

Life history of the long-lived gynodioecious cushion plant Silene acaulis (Caryophyllaceae), inferred from size-based population projection matrices.

Journal Article American journal of botany · June 1998 Alpine plants often appear to have long life-spans as an adaptation to harsh and unpredictable environmental conditions, yet many lack reliable indicators of age that would make it possible to determine their true longevity. Their extended life-spans also ... Full text Cite

Modeling controlled burning and trampling reduction for conservation of Hudsonia montana

Journal Article Conservation Biology · January 1, 1998 Populations of mountain golden heather (Hudsonia montana), a threatened North Carolina shrub, are declining due to the suppression of natural fires and increased trampling by hikers and campers. Consequently, proposed management strategies have focused on ... Full text Cite

Disentangling effects of induced plant defenses and food quantity on herbivores by fitting nonlinear models.

Journal Article The American naturalist · September 1997 Plants can respond to herbivore damage through both broad-scale (systemic) and localized induced responses. While many studies have quantified the impact of systemic responses on herbivores, measuring the impact of localized changes is difficult because pl ... Full text Cite

Population consequences of constitutive and inducible plant resistance: herbivore spatial spread.

Journal Article The American naturalist · June 1997 Little attention has been paid to the impact that constitutive and inducible plant resistance traits will have on herbivore spatial dynamics. We investigate mathematical models in which herbivore demographic rates and movement rates respond to host plant q ... Full text Cite

Mutualism denied? Nectar-robbing bumble bees do not reduce female or male success of bluebells

Journal Article Ecology · January 1, 1996 Although mutualisms are often viewed as fragile constructs, subject to invasion by "cheaters" that gain from the mutualism without providing compensating benefits, few studies have explored whether or not apparent cheating behavior by one player actually d ... Full text Cite

Mechanisms of pollen deposition by insect pollinators

Journal Article Evolutionary Ecology · May 1, 1995 Studies of pollen dispersal in insect-pollinated plants have often documented highly leptokurtic patterns of pollen deposition that can increase the likelihood of long-distance mating. To examine potential causes of highly leptokurtic deposition, we introd ... Full text Cite

Studying and managing the risk of cross‐fertilization between transgenic crops and wild relatives

Journal Article Molecular Ecology · January 1, 1994 Drawing on field studies of pollen dispersal, we identify features of the hybridization process that need quantification. Our emphasis is on standardized measures, as opposed to the idiosyncratic and often anecdotal methods with which gene flow or out‐cros ... Full text Cite

Do barren zones and pollen traps reduce gene escape from transgenic crops?

Journal Article Ecological Applications · January 1, 1994 Full text Cite

A general test for interaction modification

Journal Article Ecology · January 1, 1994 Full text Cite

Predicting the consequences of plant spacing and biased movement for pollen dispersal by honey bees

Journal Article Ecology · January 1, 1993 Easily measured characteristics of pollinator movement and pollen deposition can be used to build models that generate quantitative predictions about pollen dispersal distance. Honey bees Apis mellifera foraged on one-dimensional arrays of mustard plants B ... Full text Cite

The effects of natural enemies, competition, and host plant water availability on an aphid population

Journal Article Oecologia · June 1, 1992 I used a factorial experiment repeated in two years to assess the relative effects of natural enemy attack, interspecific competition, and water availability to the host plant, and of interactions among these factors, on the population dynamics of the aphi ... Full text Cite

Causes and consequences of spatial aggregation in the phytophagous beetle Altica tombacina

Journal Article Journal of Animal Ecology · January 1, 1992 Eggs, larvae and adults of the flea beetle Altica tombacina were consistently aggregated among stems of fireweed Epilobium angustifolium in a 3-yr census. Aggregation was due in part to the fact that flea beetle eggs are laid in clutches. Adult beetles rem ... Full text Cite

Problems in detecting chaotic behavior in natural populations by fitting simple discrete models

Journal Article Ecology · January 1, 1990 In order to predict the long-term qualitative dynamics of natural populations with discrete generations, ecologists have used short-term field data to estimate the parameters of simple difference-equation models whose behaviors are then examined. Three pro ... Full text Cite

Ecological constraints to seedling establishment on the Pumice Plains, Mount St Helens, Washington

Journal Article American Journal of Botany · January 1, 1990 For both Epilobium angustifolium and Anaphalis margaritacea, the dominant species in primary succession on the Pumice Plains, density of the seed rain far exceeds the density of colonists. A. margaritacea established under a wider range of conditions than ... Full text Cite

The role of lupine in succession on Mount St. Helens: facilitation or inhibition

Journal Article Ecology · January 1, 1989 Investigated the influence of Lupinus lepidus, a nitrogen-fixing pioneer species, on 2 invading species, Anaphalis margaritacea and Epilobium angustifolium. Patches of L. lepidus exerted both facilitative and inhibitory effects on the other species. First ... Full text Cite

Seed dispersal and seedling emergence in an old field community in central New York (USA)

Journal Article Oecologia · August 1, 1986 Seed dispersal and seedling emergence of common taxa growing in a Solidago-dominated old field in central New York (USA) were monitored from May 1982 to June 1984. Over 3.5x104 seeds per m2 were captured on seed traps in each of the two years, with peaks o ... Full text Cite