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Niv Demalach

The Hebrew University of Jerusalem, Institute of Plant Sciences and genetics in Agriculture, Faculty Member

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Trinity College Dublin

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Papers by Niv Demalach

The effects of ecological selection on species diversity and trait distribution: predictions and an empirical test

arXiv (Cornell University), Aug 21, 2019

Ecological selection is a major driver of community assembly. Selection is classified as stabiliz... more Ecological selection is a major driver of community assembly. Selection is classified as stabilizing when species with intermediate trait values gain the highest reproductive success, whereas selection is considered directional when fitness is highest for species with extreme trait values. Previous studies have investigated the effects of different selection types on trait distribution, but the effects of selection on species diversity have remained unclear. Here, we propose a framework for inferring the type and strength of selection by studying species diversity and trait distribution together against null expectations. We use a simulation model to confirm our prediction that directional selection should lead to lower species diversity than stabilizing selection despite a similar effect on trait community-weighted variance. We apply the framework to a mesocosm system of annual plants to test whether differences in species diversity between two habitats that vary in productivity are related to differences in selection on seed mass. We show that, in both habitats, species diversity was lower than the null expectation, but that species diversity was lower in the more productive habitat. We attribute this difference to strong directional selection for large-seeded species in the productive habitat as indicated by trait community-weighted-mean being higher and community-weighted variance being lower than the null expectations. In the less productive habitat, we found that community-weighted variance was higher than expected by chance, suggesting that seed mass could be a driver of niche partitioning under such conditions. Altogether, our results suggest that viewing species diversity and trait distribution as interrelated patterns driven by the same process, ecological selection, is helpful in understanding community assembly. Ecological selection

Alternative states in plant communities driven by a life-history tradeoff and demographic stochasticity

arXiv (Cornell University), Dec 10, 2018

Life-history tradeoffs among species are major drivers of community assembly. Most studies invest... more Life-history tradeoffs among species are major drivers of community assembly. Most studies investigate how tradeoffs promote deterministic coexistence of species. It remains unclear how tradeoffs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states. Focusing on the establishment-longevity tradeoff, in which high longevity is associated with low competitive ability during establishment, we study the transient dynamics and equilibrium outcomes of competitive interactions in a simulation model of plant community assembly. We show that, in this model, the establishmentlongevity tradeoff is a necessary but not sufficient condition for alternative stable equilibria, which also require low fecundity for both species. An analytical approximation of our simulation model demonstrates that alternative stable equilibria are driven by demographic stochasticity in the number of seeds arriving at each establishment site. This site-scale stochasticity is only affected by fecundity and therefore occurs even in infinitely large communities. In many cases where the establishmentlongevity tradeoff does not cause alternative stable equilibria, it still decreases the rate of convergence toward the single equilibrium, resulting in decades of transient dynamics that can appear indistinguishable from alternative stable equilibria in empirical studies.

Revising the global biogeography of annual and perennial plants

Nature

Review for "Litter accumulation, not light limitation, drives early plant recruitment

Density‐dependent and independent mechanisms jointly reduce species performance under nitrogen enrichment

Oikos

Nitrogen (N) deposition is a primary driver of species loss in plant communities globally. Howeve... more Nitrogen (N) deposition is a primary driver of species loss in plant communities globally. However, the mechanisms by which high N availability causes species loss remain unclear. Many hypotheses for species loss with increasing N availability highlight density‐dependent mechanisms, i.e. changes in species interactions. However, an alternative set of hypotheses highlights density‐independent detrimental effects of nitrogen (e.g. N toxicity). We tested the role of density‐dependent and density‐independent mechanisms in reducing species performance. For this aim, we used 120 experimental plant communities (mesocosms) comprised of annual species growing together in containers under four fertilization treatments: 1) no nutrient addition (control), 2) all nutrients except N (P, K, and micronutrients), 3) low N (3 gN m−2) + other nutrients, and 4) high N (15 gN m−2) + other nutrients. Each fertilization treatment included two sowing densities to differentiate between the effects of compet...

Review for "More warm‐adapted species in soil seed banks than in herb layer plant communities across Europe

The soil seed bank reduces density fluctuations with increasing aridity

Datasets and R code used in the paper. To run the code please download all files to the same dire... more

Succession and priority effects between annual and perennial plants

Contrasting dynamics of seed banks and standing vegetation of annuals and perennials along a rainfall gradient

Perspectives in Plant Ecology, Evolution and Systematics

The soil seed bank is a major component of plant communities. However, long-term analyses of the ... more The soil seed bank is a major component of plant communities. However, long-term analyses of the dynamics of the seed bank and the ensuing vegetation are rare. Here, we studied the dynamics in plant communities with high dominance of annuals in Mediterranean, semiarid, and arid ecosystems for nine consecutive years. For annuals, we hypothesized that the density

Review for "Species loss due to nutrient addition increases with spatial scale in global grasslands

Toward a trait-based species pool hypothesis

arXiv: Populations and Evolution, 2019

The species pool hypothesis highlights the effects of historical processes and past adaptation on... more The species pool hypothesis highlights the effects of historical processes and past adaptation on contemporary patterns of species diversity. This hypothesis has been contentious because it is difficult to test. Here we argue that a trait-based approach enables an effective test of this hypothesis where increasing mismatch between community mean trait values (the optimal trait strategy) and the mean of the species pool (representing historical legacy) decreases species diversity. We confirm this prediction using a simulation model and demonstrate its utility using experimental communities of annual plants. Using this case study, we show that our hypothesis is more easily falsifiable than the classical species pool hypothesis and could be applied as a null hypothesis to any system. We also discuss the implications of our framework for the relationship between species diversity and functional diversity and propose additional testable predictions for classical hypotheses invoking past ...

Toward a mechanistic understanding of the effects of nitrogen and phosphorus additions on grassland diversity

Perspectives in Plant Ecology, Evolution and Systematics, 2018

Highlights  While N additions decrease species richness, the effects of P additions are mainly n... more Highlights  While N additions decrease species richness, the effects of P additions are mainly neutral.  The difference is partly explained by differences in biomass production, litter production and light availability.  There are additional resource-specific effects.  A graphical model for testing the various resource-specific mechanisms is proposed.

Revising the global biogeography of plant life cycles

Plants exhibit two primary life cycles – annual and perennial – which vary in their effects on ec... more Plants exhibit two primary life cycles – annual and perennial – which vary in their effects on ecosystem functioning. Here, we assembled a database of 235,000 species to assess the worldwide distribution of plant life cycles. We found that annuals are half as common as previously thought (6% of all plant species). Furthermore, our analysis demonstrates that annuals are favored under hot and dry conditions, especially under a prolonged dry season. Strikingly, this pattern remains consistent among different families, indicating convergent evolution. Moreover, we show that increasing climate variability and anthropogenic disturbance further increase the favorability of annuals. Overall, our analysis raises concerns for the future of ecosystem services provided by perennials because the ongoing climate and land-use changes are leading to an annuals-dominated world.One-Sentence SummaryThis extensive update to plant life cycle biogeography deciphers their dependence on temperature, rainfa...

Depositus and Depositio in Early Christian Epitaphs as Evidence of Belief That the Dead Will Rise

Abstract not availabl

Assessing the roles of nitrogen, biomass, and niche dimensionality as drivers of species loss in grassland communities

Proceedings of the National Academy of Sciences, 2022

Significance Nutrient enrichment of natural ecosystems is a primary characteristic of the Anthrop... more Significance Nutrient enrichment of natural ecosystems is a primary characteristic of the Anthropocene and a known cause of biodiversity loss, particularly in grasslands. In a global meta-analysis of 630 resource addition experiments, we conduct a simultaneous test of the three most prominent explanations of this phenomenon. Our results conclusively indicate that nitrogen is the leading cause of species loss. This result is important because of the increase in nitrogen deposition and the frequent use of nitrogen-based fertilizers worldwide. Our findings provide global-scale, experimental evidence that minimizing nitrogen inputs to ecological systems may help to conserve the diversity of grassland ecosystems.

Results of a small-scale clipping experiment mimicking the effect of biomass removal by the cattle on the vegetation in the study area (removal of all shoots higher than 7 cm)

<p>The experiment was conducted within experimental units of 0.16m<sup>2</sup> ... more

Coexistence under Hierarchical Resource Exploitation: The Role of the R*-Preemption Trade-Off

The American Naturalist

Resource competition theory predicts coexistence and exclusion patterns based on species' R * s, ... more Resource competition theory predicts coexistence and exclusion patterns based on species' R * s, the minimum resource values required for a species to persist. A central assumption of the theory is that all species have equal access to resources. However, many systems are characterized by preemption exploitation, where some species deplete resources before their competitors can access them (e.g., asymmetric light competition, contest competition among animals). We hypothesized that coexistence under preemption requires an R *-preemption trade-off-that is, the species with the priority access should have a higher R * (lower "efficiency"). Thus, we developed an extension of resource competition theory to investigate partial and total preemption (in the latter, the preemptor is unaffected by species with lower preemption rank). We found that an R *-preemption trade-off is a necessary condition for coexistence in all models. Moreover, under total preemption, the trade-off alone is sufficient for coexistence. In contrast, under partial preemption, more conditions are needed, which restricts the parameter space of coexistence. Finally, we discuss the implications of our finding for seemingly distinct trade-offs, which we view as special cases of the R *-preemption trade-off. These trade-offs include the digger-grazer trade-off, the competition-colonization trade-off, and trade-offs related to light competition between trees and understories.

Assessing the roles of nitrogen, biomass, and niche dimensionality as drivers of species loss in grassland communities

by Nir Band and Niv Demalach

Proceedings of the National Academy of Sciences, 2022

Eutrophication is a major driver of species loss in plant communities worldwide. However, the und... more Eutrophication is a major driver of species loss in plant communities worldwide. However, the underlying mechanisms of this phenomenon are controversial. Previous studies have raised three main explanations: 1) High levels of soil resources increase standing biomass, thereby intensifying competitive interactions (the “biomass-driven competition hypothesis”). 2) High levels of soil resources reduce the potential for resource-based niche partitioning (the “niche dimension hypothesis”). 3) Increasing soil nitrogen causes stress by changing the abiotic or biotic conditions (the “nitrogen detriment hypothesis”). Despite several syntheses of resource addition experiments, so far, no study has tested all of the hypotheses together. This is a major shortcoming, since the mechanisms underlying the three hypotheses are not independent. Here, we conduct a simultaneous test of the three hypotheses by integrating data from 630 resource addition experiments located in 99 sites worldwide. Our results provide strong support for the nitrogen detriment hypothesis, weaker support for the biomass-driven competition hypothesis, and negligible support for the niche dimension hypothesis. The results further show that the indirect effect of nitrogen through its effect on biomass is minor compared to its direct effect and is much larger than that of all other resources (phosphorus, potassium, and water). Thus, we conclude that nitrogen-specific mechanisms are more important than biomass or niche dimensionality as drivers of species loss under high levels of soil resources. This conclusion is highly relevant for future attempts to reduce biodiversity loss caused by global eutrophication.

Alternative stable states driven by a life-history tradeoff

Matlab Codes for the paper 'Alternative stable states driven by a life-history tradeoff'.... more Matlab Codes for the paper 'Alternative stable states driven by a life-history tradeoff'. These files include the models from the main text and the appendix. I recommend downloading all the files into the same directory before running them because the scripts are using functions which are located in different files. <br>please read the file 'matlab codes for the paper' for brief description of the codes

Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity

The American Naturalist, 2021

Life-history tradeoffs among species are major drivers of community assembly. Most studies invest... more Life-history tradeoffs among species are major drivers of community assembly. Most studies investigate how tradeoffs promote deterministic coexistence of species. It remains unclear how tradeoffs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states. Focusing on the establishment-longevity tradeoff, in which high longevity is associated with low competitive ability during establishment, we study the transient dynamics and equilibrium outcomes of competitive interactions in a simulation model of plant community assembly. We show that, in this model, the establishmentlongevity tradeoff is a necessary but not sufficient condition for alternative stable equilibria, which also require low fecundity for both species. An analytical approximation of our simulation model demonstrates that alternative stable equilibria are driven by demographic stochasticity in the number of seeds arriving at each establishment site. This site-scale stochasticity is only affected by fecundity and therefore occurs even in infinitely large communities. In many cases where the establishmentlongevity tradeoff does not cause alternative stable equilibria, it still decreases the rate of convergence toward the single equilibrium, resulting in decades of transient dynamics that can appear indistinguishable from alternative stable equilibria in empirical studies.

The effects of ecological selection on species diversity and trait distribution: predictions and an empirical test

arXiv (Cornell University), Aug 21, 2019

Ecological selection is a major driver of community assembly. Selection is classified as stabiliz... more Ecological selection is a major driver of community assembly. Selection is classified as stabilizing when species with intermediate trait values gain the highest reproductive success, whereas selection is considered directional when fitness is highest for species with extreme trait values. Previous studies have investigated the effects of different selection types on trait distribution, but the effects of selection on species diversity have remained unclear. Here, we propose a framework for inferring the type and strength of selection by studying species diversity and trait distribution together against null expectations. We use a simulation model to confirm our prediction that directional selection should lead to lower species diversity than stabilizing selection despite a similar effect on trait community-weighted variance. We apply the framework to a mesocosm system of annual plants to test whether differences in species diversity between two habitats that vary in productivity are related to differences in selection on seed mass. We show that, in both habitats, species diversity was lower than the null expectation, but that species diversity was lower in the more productive habitat. We attribute this difference to strong directional selection for large-seeded species in the productive habitat as indicated by trait community-weighted-mean being higher and community-weighted variance being lower than the null expectations. In the less productive habitat, we found that community-weighted variance was higher than expected by chance, suggesting that seed mass could be a driver of niche partitioning under such conditions. Altogether, our results suggest that viewing species diversity and trait distribution as interrelated patterns driven by the same process, ecological selection, is helpful in understanding community assembly. Ecological selection

Alternative states in plant communities driven by a life-history tradeoff and demographic stochasticity

arXiv (Cornell University), Dec 10, 2018

Life-history tradeoffs among species are major drivers of community assembly. Most studies invest... more Life-history tradeoffs among species are major drivers of community assembly. Most studies investigate how tradeoffs promote deterministic coexistence of species. It remains unclear how tradeoffs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states. Focusing on the establishment-longevity tradeoff, in which high longevity is associated with low competitive ability during establishment, we study the transient dynamics and equilibrium outcomes of competitive interactions in a simulation model of plant community assembly. We show that, in this model, the establishmentlongevity tradeoff is a necessary but not sufficient condition for alternative stable equilibria, which also require low fecundity for both species. An analytical approximation of our simulation model demonstrates that alternative stable equilibria are driven by demographic stochasticity in the number of seeds arriving at each establishment site. This site-scale stochasticity is only affected by fecundity and therefore occurs even in infinitely large communities. In many cases where the establishmentlongevity tradeoff does not cause alternative stable equilibria, it still decreases the rate of convergence toward the single equilibrium, resulting in decades of transient dynamics that can appear indistinguishable from alternative stable equilibria in empirical studies.

Revising the global biogeography of annual and perennial plants

Nature

Review for "Litter accumulation, not light limitation, drives early plant recruitment

Density‐dependent and independent mechanisms jointly reduce species performance under nitrogen enrichment

Oikos

Nitrogen (N) deposition is a primary driver of species loss in plant communities globally. Howeve... more Nitrogen (N) deposition is a primary driver of species loss in plant communities globally. However, the mechanisms by which high N availability causes species loss remain unclear. Many hypotheses for species loss with increasing N availability highlight density‐dependent mechanisms, i.e. changes in species interactions. However, an alternative set of hypotheses highlights density‐independent detrimental effects of nitrogen (e.g. N toxicity). We tested the role of density‐dependent and density‐independent mechanisms in reducing species performance. For this aim, we used 120 experimental plant communities (mesocosms) comprised of annual species growing together in containers under four fertilization treatments: 1) no nutrient addition (control), 2) all nutrients except N (P, K, and micronutrients), 3) low N (3 gN m−2) + other nutrients, and 4) high N (15 gN m−2) + other nutrients. Each fertilization treatment included two sowing densities to differentiate between the effects of compet...

Review for "More warm‐adapted species in soil seed banks than in herb layer plant communities across Europe

The soil seed bank reduces density fluctuations with increasing aridity

Datasets and R code used in the paper. To run the code please download all files to the same dire... more

Succession and priority effects between annual and perennial plants

Contrasting dynamics of seed banks and standing vegetation of annuals and perennials along a rainfall gradient

Perspectives in Plant Ecology, Evolution and Systematics

The soil seed bank is a major component of plant communities. However, long-term analyses of the ... more The soil seed bank is a major component of plant communities. However, long-term analyses of the dynamics of the seed bank and the ensuing vegetation are rare. Here, we studied the dynamics in plant communities with high dominance of annuals in Mediterranean, semiarid, and arid ecosystems for nine consecutive years. For annuals, we hypothesized that the density

Review for "Species loss due to nutrient addition increases with spatial scale in global grasslands

Toward a trait-based species pool hypothesis

arXiv: Populations and Evolution, 2019

The species pool hypothesis highlights the effects of historical processes and past adaptation on... more The species pool hypothesis highlights the effects of historical processes and past adaptation on contemporary patterns of species diversity. This hypothesis has been contentious because it is difficult to test. Here we argue that a trait-based approach enables an effective test of this hypothesis where increasing mismatch between community mean trait values (the optimal trait strategy) and the mean of the species pool (representing historical legacy) decreases species diversity. We confirm this prediction using a simulation model and demonstrate its utility using experimental communities of annual plants. Using this case study, we show that our hypothesis is more easily falsifiable than the classical species pool hypothesis and could be applied as a null hypothesis to any system. We also discuss the implications of our framework for the relationship between species diversity and functional diversity and propose additional testable predictions for classical hypotheses invoking past ...

Toward a mechanistic understanding of the effects of nitrogen and phosphorus additions on grassland diversity

Perspectives in Plant Ecology, Evolution and Systematics, 2018

Highlights  While N additions decrease species richness, the effects of P additions are mainly n... more Highlights  While N additions decrease species richness, the effects of P additions are mainly neutral.  The difference is partly explained by differences in biomass production, litter production and light availability.  There are additional resource-specific effects.  A graphical model for testing the various resource-specific mechanisms is proposed.

Revising the global biogeography of plant life cycles

Plants exhibit two primary life cycles – annual and perennial – which vary in their effects on ec... more Plants exhibit two primary life cycles – annual and perennial – which vary in their effects on ecosystem functioning. Here, we assembled a database of 235,000 species to assess the worldwide distribution of plant life cycles. We found that annuals are half as common as previously thought (6% of all plant species). Furthermore, our analysis demonstrates that annuals are favored under hot and dry conditions, especially under a prolonged dry season. Strikingly, this pattern remains consistent among different families, indicating convergent evolution. Moreover, we show that increasing climate variability and anthropogenic disturbance further increase the favorability of annuals. Overall, our analysis raises concerns for the future of ecosystem services provided by perennials because the ongoing climate and land-use changes are leading to an annuals-dominated world.One-Sentence SummaryThis extensive update to plant life cycle biogeography deciphers their dependence on temperature, rainfa...

Depositus and Depositio in Early Christian Epitaphs as Evidence of Belief That the Dead Will Rise

Abstract not availabl

Assessing the roles of nitrogen, biomass, and niche dimensionality as drivers of species loss in grassland communities

Proceedings of the National Academy of Sciences, 2022

Significance Nutrient enrichment of natural ecosystems is a primary characteristic of the Anthrop... more Significance Nutrient enrichment of natural ecosystems is a primary characteristic of the Anthropocene and a known cause of biodiversity loss, particularly in grasslands. In a global meta-analysis of 630 resource addition experiments, we conduct a simultaneous test of the three most prominent explanations of this phenomenon. Our results conclusively indicate that nitrogen is the leading cause of species loss. This result is important because of the increase in nitrogen deposition and the frequent use of nitrogen-based fertilizers worldwide. Our findings provide global-scale, experimental evidence that minimizing nitrogen inputs to ecological systems may help to conserve the diversity of grassland ecosystems.

Results of a small-scale clipping experiment mimicking the effect of biomass removal by the cattle on the vegetation in the study area (removal of all shoots higher than 7 cm)

<p>The experiment was conducted within experimental units of 0.16m<sup>2</sup> ... more

Coexistence under Hierarchical Resource Exploitation: The Role of the R*-Preemption Trade-Off

The American Naturalist

Resource competition theory predicts coexistence and exclusion patterns based on species' R * s, ... more Resource competition theory predicts coexistence and exclusion patterns based on species' R * s, the minimum resource values required for a species to persist. A central assumption of the theory is that all species have equal access to resources. However, many systems are characterized by preemption exploitation, where some species deplete resources before their competitors can access them (e.g., asymmetric light competition, contest competition among animals). We hypothesized that coexistence under preemption requires an R *-preemption trade-off-that is, the species with the priority access should have a higher R * (lower "efficiency"). Thus, we developed an extension of resource competition theory to investigate partial and total preemption (in the latter, the preemptor is unaffected by species with lower preemption rank). We found that an R *-preemption trade-off is a necessary condition for coexistence in all models. Moreover, under total preemption, the trade-off alone is sufficient for coexistence. In contrast, under partial preemption, more conditions are needed, which restricts the parameter space of coexistence. Finally, we discuss the implications of our finding for seemingly distinct trade-offs, which we view as special cases of the R *-preemption trade-off. These trade-offs include the digger-grazer trade-off, the competition-colonization trade-off, and trade-offs related to light competition between trees and understories.

Assessing the roles of nitrogen, biomass, and niche dimensionality as drivers of species loss in grassland communities

by Nir Band and Niv Demalach

Proceedings of the National Academy of Sciences, 2022

Eutrophication is a major driver of species loss in plant communities worldwide. However, the und... more Eutrophication is a major driver of species loss in plant communities worldwide. However, the underlying mechanisms of this phenomenon are controversial. Previous studies have raised three main explanations: 1) High levels of soil resources increase standing biomass, thereby intensifying competitive interactions (the “biomass-driven competition hypothesis”). 2) High levels of soil resources reduce the potential for resource-based niche partitioning (the “niche dimension hypothesis”). 3) Increasing soil nitrogen causes stress by changing the abiotic or biotic conditions (the “nitrogen detriment hypothesis”). Despite several syntheses of resource addition experiments, so far, no study has tested all of the hypotheses together. This is a major shortcoming, since the mechanisms underlying the three hypotheses are not independent. Here, we conduct a simultaneous test of the three hypotheses by integrating data from 630 resource addition experiments located in 99 sites worldwide. Our results provide strong support for the nitrogen detriment hypothesis, weaker support for the biomass-driven competition hypothesis, and negligible support for the niche dimension hypothesis. The results further show that the indirect effect of nitrogen through its effect on biomass is minor compared to its direct effect and is much larger than that of all other resources (phosphorus, potassium, and water). Thus, we conclude that nitrogen-specific mechanisms are more important than biomass or niche dimensionality as drivers of species loss under high levels of soil resources. This conclusion is highly relevant for future attempts to reduce biodiversity loss caused by global eutrophication.

Alternative stable states driven by a life-history tradeoff

Matlab Codes for the paper 'Alternative stable states driven by a life-history tradeoff'.... more Matlab Codes for the paper 'Alternative stable states driven by a life-history tradeoff'. These files include the models from the main text and the appendix. I recommend downloading all the files into the same directory before running them because the scripts are using functions which are located in different files. <br>please read the file 'matlab codes for the paper' for brief description of the codes

Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity

The American Naturalist, 2021

Life-history tradeoffs among species are major drivers of community assembly. Most studies invest... more Life-history tradeoffs among species are major drivers of community assembly. Most studies investigate how tradeoffs promote deterministic coexistence of species. It remains unclear how tradeoffs may instead promote historically contingent exclusion of species, where species dominance is affected by initial abundances, causing alternative community states. Focusing on the establishment-longevity tradeoff, in which high longevity is associated with low competitive ability during establishment, we study the transient dynamics and equilibrium outcomes of competitive interactions in a simulation model of plant community assembly. We show that, in this model, the establishmentlongevity tradeoff is a necessary but not sufficient condition for alternative stable equilibria, which also require low fecundity for both species. An analytical approximation of our simulation model demonstrates that alternative stable equilibria are driven by demographic stochasticity in the number of seeds arriving at each establishment site. This site-scale stochasticity is only affected by fecundity and therefore occurs even in infinitely large communities. In many cases where the establishmentlongevity tradeoff does not cause alternative stable equilibria, it still decreases the rate of convergence toward the single equilibrium, resulting in decades of transient dynamics that can appear indistinguishable from alternative stable equilibria in empirical studies.