Disparate responses of above‐ and belowground properties to soil disturbance by an invasive mammal

Abstract

Abstract. Introduced mammalian herbivores can negatively affect ecosystem structure and function if they introduce a novel disturbance to an ecosystem. For example, belowground foraging herbivores that bioturbate the soil, may alter process rates and community composition in ecosystems that lack native belowground mammalian foragers. Wild boar (Sus scrofa) disturb the soil system and plant community via their rooting behavior in their native range. Given their size and the numbers in their populations, this disturbance can be significant in forested ecosystems. Recently, wild boar were introduced to Patagonian forests lacking native mammalian herbivores that forage belowground. To explore how introduced wild boar might alter forested ecosystems, we conducted a large-scale wild boar exclusion experiment in three different forest types (Austroducedrus chilensis forest, Nothofagus dombeyi forest, and shrublands). Wild boar presence altered plant composition and structure, reducing plant biomass 3.8-fold and decreasing both grass and herb cover relative to areas where wild boar were excluded. Decomposition rates and soil compaction also declined by 5% in areas where boar had access; however, rooting had no effect on soil nutrient stocks and cycling. Interestingly, there were no differences in wild boar impacts on different forest types. We found that after 3-years of exclusion, belowground foraging by wild boar had a larger impact on plant community structure and biomass than it did on soil nutrient processes.

Mycophagy by invasive wild boar (Sus scrofa) facilitates dispersal of native and introduced mycorrhizal fungi in Patagonia, Argentina

“…Los Alerces, Lago Puelo, Nahuel Huapi, Lanín, Lihue-Calel, Sierra de las Quijadas, El Palmar, and Reserva El Leoncito) (Novillo and Ojeda, 2008;Schiaffini and Vila, 2012). In Patagonia, its presence has been confirmed by direct observation and by the presence of feces and rooted patches produced as a consequence of the feeding habit (Barrios-Garcia et al, 2014).…”

Soil biological responses to, and feedbacks on, trophic rewilding

“…Whether this scales up to landscape-level effects is unclear. Short-term exclusion studies on invasive boars and feral pigs showed weak effects on soil properties [48,49], but studies of longer duration showed strong effects on nutrient cycling and uptake by plants [50] and on soil microarthropod populations [51]. In fact, in European ecosystems in which they occur naturally, boars significantly affect soil properties [52] and fauna [53,54].…”

Towards a more holistic research approach to plant conservation: the case of rare plants on oceanic islands

“…2003 ; Garzón-Machado et al . 2010 , Barrios-Garcia et al . 2014 ); (vi) species distribution models (SDMs) to determine environmental constraints and potentially favourable areas, possible impacts of climate change and of other anthropogenic alterations ( Costa et al 2012 , 2013 a ; Marcer et al .…”