Plant controls on Late Quaternary whole ecosystem structure and function

Abstract

Plants and animals influence biomass production and nutrient cycling in terrestrial ecosystems; however, their relative importance remains unclear. We assessed the extent to which mega-herbivore species controlled plant community composition and nutrient cycling, relative to other factors during and after the Late Quaternary extinction event in Britain and Ireland, when two-thirds of the region's mega-herbivore species went extinct. Warmer temperatures, plant-soil and plant-plant interactions, and reduced burning contributed to the expansion of woody plants and declining nitrogen availability in our five study ecosystems. Shrub biomass was consistently one of the strongest predictors of ecosystem change, equalling or exceeding the effects of other biotic and abiotic factors. In contrast, there was relatively little evidence for mega-herbivore control on plant community composition and nitrogen availability. The ability of plants to determine the fate of terrestrial ecosystems during periods of global environmental change may therefore be greater than previously thought.

Unprecedented herbivory threatens rear‐edge populations of Betula in southwestern Eurasia

“…This main conclusion complements previous research showing that under natural conditions herbivory did not pose relevant constraints to vegetation dynamics (Jeffers et al. ).…”

“…Thus, herbivory can significantly contribute to defining long-term vegetation composition and structure in ecosystems where the natural equilibrium is disrupted by human activities (e.g., lack of predators). This main conclusion complements previous research showing that under natural conditions herbivory did not pose relevant constraints to vegetation dynamics (Jeffers et al 2018).…”

Using paleo-archives to safeguard biodiversity under climate change

“…Although in many biogeographic regions, these events are comparable in pace and magnitude to 21 st century forecasts (16), they do not offer a direct analog for future global warming from recent anthropogenic climate forcing (17). Nevertheless, they can reveal actual species-and ecosystem-level responses to previous rapid changes in climate (11,12,18,19). Indeed, one of the most powerful features of the paleo record is its heuristic nature (20), providing concrete narratives, scenarios, and other thinking tools to better anticipate and visualize the potential ecological and evolutionary consequences of future climate change, enhancing knowledge of principles and mechanisms for conserving biodiversity and ecosystem services (6,7).…”

Fir expansion not controlled by moderate densities of large herbivores: a Mediterranean mountain grassland conservation issue

“…Generally speaking, a lowdensity presence of herbivores in forests does not prevent tree encroachment and expansion as long as other disturbances (e.g. fire, windthrow, clear-cut) are not associated with it (Peringer et al 2017;Boulanger et al 2018;Jeffers et al 2018), whilst high-density of herbivores can be extremely efficient, including on unpalatable species like pines (e.g. Chauchard et al 2006).…”