{"id":583,"date":"2021-09-17T01:52:19","date_gmt":"2021-09-17T01:52:19","guid":{"rendered":"https:\/\/esa.org\/vegetation\/?page_id=583"},"modified":"2025-08-18T16:55:19","modified_gmt":"2025-08-18T16:55:19","slug":"mcintosh-award-winners","status":"publish","type":"page","link":"https:\/\/esa.org\/vegetation\/awards\/robert-p-mcintosh-award\/mcintosh-award-winners\/","title":{"rendered":"McIntosh Award Winners"},"content":{"rendered":"\n

2025 McIntosh Award for best paper in vegetation ecology<\/strong><\/span><\/p>\n\n\n\n

LaMontagne, J.M., Greene, D.F., Holland, E.P., Johnstone, J.F., Schulze, M., Zimmerman, J.K., Lyon, N.J., Chen, A., Miller, T.E.X., Nigro, K.M., Snell, R.S., Barton, J.H., Chaudhary, V.B., Cleavitt, N.L., Crone, E.E., Koenig, W.D., Macias, D., Pearse, I.S. and Redmond, M.D. (2024) Community Synchrony in Seed Production is Associated With Trait Similarity and Climate Across North America. Ecology Letters<\/em>\u00a027: e14498. https:\/\/doi.org\/10.1111\/ele.14498<\/a>\u00a0<\/p>\n\n\n\n

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Jalene LaMontagne and coauthors<\/figcaption><\/figure>\n\n\n\n

Mast seeding, the synchronous and highly variable production of seed crops by perennial plants, is a population-level phenomenon and has cascading effects in ecosystems. Mast seeding studies are typically conducted at the population\/species level. Much less is known about synchrony in mast seeding between co-occurring species because the necessary long-term data are rarely available. To investigate synchrony between species within communities, we used long-term data from seven forest communities in the U.S. Long-Term Ecological Research (LTER) network, ranging across 46.5\u00b0 of latitude and 82\u00b0 of longitude, from tropical rainforest to boreal forest. These LTER sites included H.J. Andrews Experimental Forest (AND), Bonanza Creek (BNZ), Cedar Creek (CDR), Coweeta (CWT), Hubbard Brook Experimental Forest (HBR), Luquillo (LUQ) and Seviletta (SEV). We focused on levels of temporal synchrony in seed production between co-occurring species (\u201ccross-species synchrony\u201d) and (i) quantified synchrony in reproduction overall and within LTER sites, (ii) tested for relationships between synchrony with trait and phylogenetic similarity and (iii) investigated how climate conditions at sites are related to levels of synchrony. Overall, reproductive synchrony between woody plant species was greater than expected by chance, but it also spanned a wide range of values between co-occurring species within LTER sites. Based on 11 functional and reproductive traits for 103 species (plus phylogenetic relatedness), cross-species synchrony in reproduction over at least 10 years (max = 58 years) was higher for species pairs with greater trait similarity, however, phylogenic similarity between species pairs was largely unimportant. Synchrony was also higher in sites with greater climatic water deficit. Community-level synchrony in mast seeding has consequences for understanding forest regeneration dynamics and for considering the role of mast seeding of single plant species in consumer-resource dynamics.<\/p>\n\n\n\n

This paper was published as a synthesis article in an Ecology Letters special issue entitled, \u201cEcological and Evolutionary Insights from Very Long-Term Studies\u201d. It is a product of the Long-Term Ecological Research (LTER) Synthesis Working Group \u2018Identifying Environmental Drivers of Plant Reproduction across LTER sites\u2019 led by J.M.L., E.E.C. and M.D.R, and funded by the LTER Network Office, National Center for Ecological Analysis and Synthesis through the U.S. National Science Foundation (NSF). The authors comprise a diverse group including across a range of career stages, from post-BSc, graduate students, to mid- and senior-career scientists. All field sites were part of the LTER network, supported by NSF, with some network sites additionally supported by the USDA Forest Service and National Forests.<\/p>\n\n\n\n

2024 McIntosh Award for best paper in vegetation ecology<\/strong><\/span><\/p>\n\n\n\n

\"Tesa
Tesa Madsen-Hepp, University of California, Riverside<\/figcaption><\/figure>\n\n\n\n

Madsen\u2010Hepp, Tesa R., Janet Franklin, Shane McFaul, Lisa Schauer, and Marko J. Spasojevic. (2023) Plant functional traits predict heterogeneous distributional shifts in response to climate change<\/a>. Functional Ecology<\/em> 37: 1449-1462.<\/p>\n\n\n\n

Abstract<\/em>:<\/p>\n\n\n\n

    \n
  1. Climate change is causing the rapid redistribution of vegetation as plant species move to track their climatic optima. Despite a global trend of upward movement in latitude and elevation, there is extensive heterogeneity among species and locations, with few emerging generalizations. Greater generalization may be achieved from considering multidimensional changes in species\u2019 distributions as well as incorporating ecologically relevant functional traits into studies of range shifts.<\/li>\n\n\n\n
  2. To better understand how recent changes in climate are influencing the elevational distribution of plant species and how species\u2019 functional traits mediate distributional changes, we resampled a 2438\u2009m elevation transect spanning a distance of 16\u2009km which encompasses desert scrub, pinyon-juniper woodland, chaparral and coniferous forest plant communities.<\/li>\n\n\n\n
  3. Over the last 42\u2009years, total perennial cover and species\u2019 average cover increased at lower elevations and decreased at higher elevations while average elevational leading-edge increased 116\u2009m and elevational rear edge decreased 84\u2009m. Notably, these changes were mediated by species\u2019 functional traits, where species exhibiting more conservative traits (lower specific leaf area [SLA], greater \u03b413<\/sup>C, larger seed mass) and taller height shifted upward in their leading-edge range limit, average elevation and trailing edge range limit, while declining in abundance at the median and trailing edge of their range. Species possessing more acquisitive traits (higher SLA, lower \u03b413<\/sup>C, smaller seed mass) and shorter height shifted downward and increased in abundance at their trailing edge, with increases in their total range size.<\/li>\n\n\n\n
  4. Our results provide clear evidence that heterogeneous range dynamics under recent climate change can be generalized by considering ecologically relevant plant functional traits, and how they respond to localized climate exposure. Furthermore, by documenting changes across a steep elevational gradient comprising a large aridity gradient, we show divergent patterns for plants occupying contrasting positions along the global spectrum of plant form and function, which provides critical insight into how trait-mediated changes under increasing aridity will impact ecosystem functioning.<\/li>\n<\/ol>\n\n\n\n

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    2023 McIntosh Award for best paper in vegetation ecology<\/strong><\/span><\/p>\n\n\n\n

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    Alyssa Young, Univ. North Carolina Greensboro<\/span><\/figcaption><\/figure>\n\n\n\n

    Young, A.L., Bloodworth, K.J., Frost, M.D.T. et al.<\/i> (2022) Heatwave implications for the future of longleaf pine savanna understory restoration<\/a>. Plant Ecology<\/i> 223:<\/b>339\u2013351.<\/p>\n\n\n\n

    The longleaf pine (LLP) savanna ecosystem once covered ~92 million acres of the Southeast USA, but due to anthropogenic activities such as logging and fire suppression, only 3% of its once widespread historic range remains. While many restoration efforts are underway to conserve this biodiverse ecosystem, restoration must be done in the context of climate change. In the last few decades, heatwaves have increased in frequency and intensity across the Southeastern USA with further increases predicted. To expand our understanding of LLP savanna restoration in light of these changes, we ran a series of three simulated heatwave greenhouse experiments through a Course-based Undergraduate Research Experience (CURE) incorporating ~150 undergraduate researchers per experiment. We measured plant growth metrics for four understory grasses commonly used in LLP savanna restoration efforts. We found that while most grass plug individuals survived heatwave conditions, above ground production was reduced due to heatwaves. This productivity decrease could result in less biomass available for the essential vegetation fire feedback loop, where fire increases grass biomass, and in turn, more grass provides more fuel for fire. These results imply that land managers can proactively compensate for biomass loss due to heatwaves by planting more grass plugs during initial restoration.<\/p>\n\n\n\n

    2022 McIntosh Award for best paper in vegetation ecology<\/span><\/strong><\/p>\n\n\n\n

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    Meghna Krishnadas @MeghnaSrishti<\/span><\/figcaption><\/figure>\n\n\n\n

    Meghna Krishnadas and Simon Maccracken Stump (2021). Dispersal limitation and weaker stabilizing mechanisms mediate loss of diversity with edge effects in forest fragments<\/a>. Journal of Ecology <\/em>109:2137\u20132151.<\/p>\n\n\n\n

    Abstract:<\/em> (1) Whether fragmented ecosystems can maintain diversity is a key ecological question. The ability of fragmented forests to support diversity is determined by both landscape-scale metapopulation dynamics and within-patch mechanisms that govern species coexistence. Within-patch dynamics can be affected by proximity to forest edges. Edge effects on abiotic and biotic processes can alter species\u2019 performance and species interactions, but it is unclear how edge effects bear upon the long-term ability of fragmented forests to maintain diversity. (2) We apply modern coexistence theory as a framework to predict the impact of edge effects on species coexistence. Using field data for a tropical tree community, we parameterized a spatially explicit simulation model to quantify how habitat and density dependence during seedling establishment affect diversity of later life stages. We matched simulated future communities to observed patterns of diversity and community structure for established seedlings and adults, coupled with sensitivity analysis of simulated effects. (3) We found that early recruitment dynamics contributed to community structure at older life stages, corroborating empirical work on the importance of early life-stage dynamics for diversity. Edge effects reduced the diversity maintained in patches. The progressive loss of diversity was not due to changes in relative competitive ability (fitness differences), but due to weaker stabilization via density-dependent seed mortality. Results were robust to wide changes in the absolute values of model parameters, suggesting that variation in the strength of individual processes did not change their relative importance for diversity. (4) Synthesis. Weakening of stabilizing processes that promote species self-limitation in ecological communities could compromise the ability of habitat fragments to maintain diversity. Quantifying the relative importance of intraspecific versus interspecific interactions\u2014to assess stabilizing mechanisms and fitness differences\u2014can help evaluate when habitat amount versus quality plays a larger role in maintaining diversity of fragments.<\/p>\n\n\n\n

    2021 McIntosh Award for best paper in vegetation ecology<\/span><\/strong><\/p>\n\n\n\n

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    Goel N., Van Vleck, E.S., Aleman, J.C., and Staver, A.C. 2020. Dispersal limitation and fire feedbacks maintain mesic savannas in Madagascar<\/a>. Ecology<\/em> 101(12):e03177.<\/p>\n\n\n\n

    Abstract:\u00a0<\/em>Madagascar is regarded by some as one of the most degraded landscapes on Earth, with estimates suggesting that 90% of forests have been lost to indigenous Tavy farming. However, the extent of this degradation has been challenged: paleoecological data, phylogeographic analysis, and species richness indicate that pyrogenic savannas in central Madagascar predate human arrival, even though rainfall is sufficient to allow forest expansion into central Madagascar. These observations raise a question\u2014if savannas in Madagascar are not anthropogenic, how then are they maintained in regions where the climate can support forest? Observation reveals that the savanna\u2013forest boundary coincides with a dispersal barrier\u2014the escarpment of the Central Plateau. Using a stepping\u2010stone model, we show that in a limited dispersal landscape, a stable savanna\u2013forest boundary can form because of fire\u2013vegetation feedbacks. This phenomenon, referred to as range pinning, could explain why eastern lowland forests have not expanded into the mesic savannas of the Central Highlands. This work challenges the view that highland savannas in Madagascar are derived by human\u2010lit fires and, more importantly, suggests that partial dispersal barriers and strong nonlinear feedbacks can pin biogeographical boundaries over a wide range of environmental conditions, providing a temporary buffer against climate change.<\/p>\n\n\n\n

    2020 McIntosh Award for best paper in vegetation ecology<\/span><\/strong><\/p>\n\n\n\n

    Alba C, Fahey C, Flory SL. 2019. Global change stressors alter resources and shift plant interactions from facilitation to competition over time.<\/a> Ecology<\/i> 100(12): e02859.<\/p>\n\n\n\n

    Abstract: <\/em>Global change stressors such as drought and plant invasion can affect ecosystem structure and function via mediation of resource availability and plant competition outcomes. Yet, it remains uncertain how native plants respond to drought stress that co\u2010occurs with potentially novel resource conditions created by a nonnative invader. Further, there is likely to be temporal variation in competition outcomes between native and nonnative plant species depending on which resources are most limiting at a given time. Interacting stressors coupled with temporal variation make it difficult to predict how global change will impact native plant communities. To address this knowledge gap, we conducted a 5\u2010yr factorial field experiment to quantify how simulated drought, plant invasion (by cogongrass,\u00a0Imperata cylindrica<\/em>), and these stressors combined, affected resource availability (soil moisture and light) and competition dynamics between the invader and native longleaf pine (Pinus palustris<\/em>), a foundation species in southeast U.S. forests. Drought and invasion mediated the survival and performance of pine seedlings in temporally dynamic and unexpected ways. Drought and invasion alone each significantly reduced pine seedling survival. However, when the stressors occurred together, the invader offset drought stress for pine seedlings by maintaining high levels of soil moisture, humidity, and shade compared to uninvaded vegetation. This facilitative effect was pronounced for 2 yr, yet shifted to strong competitive exclusion as the invasion progressed and the limiting resource switched from soil moisture to light. After 3 yr, pine tree survival was low except for pines growing with uninvaded vegetation under ambient precipitation conditions. After 5 yr, pines experiencing a single stressor were taller and had greater height to diameter ratios than pines under no stress or both stressors. This outcome revealed a filtering effect where poorly performing trees were culled under stressful conditions, especially when pines were growing with the invader. Together, these results demonstrate that although drought and invasion suppressed a foundation tree species, the invader temporarily moderated stressful drought conditions, and at least some trees were able to survive despite increasingly strong competition. Such unpredictable effects of interacting global change stressors on native plant species highlight the need for additional long\u2010term studies.<\/p>\n\n\n\n

    2019 McIntosh Award for best paper in veg<\/span><\/strong>etation ecology (inaugural award)<\/span><\/strong><\/p>\n\n\n\n

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    <\/p>\n\n\n\n

    Case, M.F. & A.C. Staver. Soil texture mediates tree responses to rainfall intensity in African savannas.<\/a> New Phytologist<\/em> 219: 1363-1372.<\/p>\n\n\n\n

    Abstract: \u2022\u00a0<\/em>Rainfall variability is a major determinant of soil moisture, but its influence on vegetation structure has been challenging to generalize. This presents a major source of uncertainty in predicting vegetation responses to potentially widespread shifts in rainfall frequency and intensity. In savannas, where trees and grasses coexist, conflicting lines of evidence have suggested, variously, that tree cover can either increase or decrease in response to less frequent, more intense rainfall. \u2022 Here, we use remote sensing products and continent\u2010wide soil maps for sub\u2010Saharan Africa to analyze how soil texture and fire mediate the response of savanna tree cover to rainfall climatology. \u2022 Tree cover increased with mean wet\u2010season rainfall and decreased with fire frequency, consistent with previous analyses. However, responses to rainfall intensity varied: tree cover dramatically decreased with rainfall intensity on clayey soils, at high rainfall, and with rainfall spread over longer wet seasons; conversely, on sandy soils, at low rainfall, and with shorter wet seasons, tree cover instead increased with rainfall intensity. \u2022 Tree cover responses to rainfall climatology depend on soil texture, accounting for substantial variation in tree cover across African savannas. Differences in underlying soils may lead to divergent responses of savannas to global change.<\/p>\n","protected":false},"excerpt":{"rendered":"

    2025 McIntosh Award for best paper in vegetation ecology LaMontagne, J.M., Greene, D.F., Holland, E.P., Johnstone, J.F., Schulze, M., Zimmerman, J.K., Lyon, N.J., Chen, A., Miller, T.E.X., Nigro, K.M., Snell, R.S., Barton, J.H., Chaudhary, V.B., Cleavitt, N.L., Crone, E.E., Koenig, W.D., Macias, D., Pearse, I.S. and Redmond, M.D. (2024) Community Synchrony in Seed Production is Associated With Trait Similarity and…<\/p>\n","protected":false},"author":1326,"featured_media":0,"parent":241,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-583","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/pages\/583","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/users\/1326"}],"replies":[{"embeddable":true,"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/comments?post=583"}],"version-history":[{"count":2,"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/pages\/583\/revisions"}],"predecessor-version":[{"id":903,"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/pages\/583\/revisions\/903"}],"up":[{"embeddable":true,"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/pages\/241"}],"wp:attachment":[{"href":"https:\/\/esa.org\/vegetation\/wp-json\/wp\/v2\/media?parent=583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}