Functional responses of understory vegetation to ungulate exclusion in temperate forest ecosystems—a comparative trait-based approach
Abstract
Key messageAn extensive exclosure-control experiment examining functional responses of forest understory vegetation revealed that ungulate exclusion favored plant traits associated with herbivory vulnerability and competitive ability, while ungulate access promoted rather disturbance-indicating communities with more acquisitive, fast-growing characteristics. This functional ecology perspective on plant-herbivore-interactions offers novel insights for both forest management and biodiversity conservation.ContextWild ungulates significantly impact temperate forest understory dynamics by affecting plant composition, diversity, and structure through their foraging strategies and movement behaviors, and can thus trigger cascading effects on ecosystem functioning. However, the functional responses of plant communities to ungulate impact remain poorly understood.AimsWe aimed (i) to test how ungulates affect plant community traits and (ii) to identify indicator species along gradients of ungulate influence (approximated as browsing percentage of woody species) and light availability (approximated as canopy coverage) during vegetation dynamics (2016–2023).MethodsBased on an extensive vegetation survey dataset of 248 paired ungulate exclosures (fenced) and control plots (unfenced), which were examined in 2016 and 2023, we assessed species-specific and functional responses of understory vegetation to ungulate exclusion via a trait-based approach, applying different plant community-weighting methods (i.e., presence/absence vs. coverage data).ResultsIn ungulate exclosures, disturbance indicator values decreased more than in unfenced controls, indicating understory recovery from browsing, grazing, and trampling. Exclosures exhibited greater reductions in specific leaf area and ruderal species proportions, but larger increases in seed mass, plant height, and forest species proportions, reflecting a shift toward traits associated with herbivory susceptibility and competitive ability. Conversely, ungulate access promoted communities with more acquisitive, fast-growing traits. Presence/absence data proved more sensitive in detecting community trait shifts than cover-weighted analyses, as dominant species may have masked changes among less abundant species. Indicator species analysis along environmental gradients revealed that ungulate feeding preferences and light availability jointly shape understory dynamics and plant–herbivore interactions.ConclusionOur findings highlight ungulates as important drivers of forest understory dynamics and underline the importance of using multiple methods to accurately assess functional responses of plant communities to herbivory.
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BibTeX
@article{seliger2026functional,
title = {{Functional responses of understory vegetation to ungulate exclusion in temperate forest ecosystems—a comparative trait-based approach}},
author = {Alexander Seliger and Jan Zäh and Steffi Heinrichs and Christian Ammer and Torsten Vor},
journal = {Annals of Forest Science},
year = {2026},
month = sep,
doi = {10.1186/s13595-026-01364-4},
url = {https://hal.science/hal-05766447v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Functional responses of understory vegetation to ungulate exclusion in temperate forest ecosystems—a comparative trait-based approach
AU - Alexander Seliger
AU - Jan Zäh
AU - Steffi Heinrichs
AU - Christian Ammer
AU - Torsten Vor
PY - 2026
DA - 2026/09/28
JO - Annals of Forest Science
DO - 10.1186/s13595-026-01364-4
UR - https://hal.science/hal-05766447v1
AB - Key messageAn extensive exclosure-control experiment examining functional responses of forest understory vegetation revealed that ungulate exclusion favored plant traits associated with herbivory vulnerability and competitive ability, while ungulate access promoted rather disturbance-indicating communities with more acquisitive, fast-growing characteristics. This functional ecology perspective on plant-herbivore-interactions offers novel insights for both forest management and biodiversity conservation.ContextWild ungulates significantly impact temperate forest understory dynamics by affecting plant composition, diversity, and structure through their foraging strategies and movement behaviors, and can thus trigger cascading effects on ecosystem functioning. However, the functional responses of plant communities to ungulate impact remain poorly understood.AimsWe aimed (i) to test how ungulates affect plant community traits and (ii) to identify indicator species along gradients of ungulate influence (approximated as browsing percentage of woody species) and light availability (approximated as canopy coverage) during vegetation dynamics (2016–2023).MethodsBased on an extensive vegetation survey dataset of 248 paired ungulate exclosures (fenced) and control plots (unfenced), which were examined in 2016 and 2023, we assessed species-specific and functional responses of understory vegetation to ungulate exclusion via a trait-based approach, applying different plant community-weighting methods (i.e., presence/absence vs. coverage data).ResultsIn ungulate exclosures, disturbance indicator values decreased more than in unfenced controls, indicating understory recovery from browsing, grazing, and trampling. Exclosures exhibited greater reductions in specific leaf area and ruderal species proportions, but larger increases in seed mass, plant height, and forest species proportions, reflecting a shift toward traits associated with herbivory susceptibility and competitive ability. Conversely, ungulate access promoted communities with more acquisitive, fast-growing traits. Presence/absence data proved more sensitive in detecting community trait shifts than cover-weighted analyses, as dominant species may have masked changes among less abundant species. Indicator species analysis along environmental gradients revealed that ungulate feeding preferences and light availability jointly shape understory dynamics and plant–herbivore interactions.ConclusionOur findings highlight ungulates as important drivers of forest understory dynamics and underline the importance of using multiple methods to accurately assess functional responses of plant communities to herbivory.
SN - 1286-4560
SN - 1297-966X
ER -