Wild ungulate overabundance in Europe: contexts, causes, monitoring and management recommendations

Abstract

High‐density populations of large ungulates are now widespread. However, the perception of overabundance only appears when it produces a problem for humans, such as a loss of plant diversity, damage to agricultural crops and forestry, ungulate‐vehicle collisions, a nuisance to humans, disease transmission to livestock or changes in habitat for other species. The admissible level of density depends on the ecological and socio‐economic context in which the population is located, and defining this level is important, in order to determine management strategies and actions. We describe the main contexts in which ungulate overabundance occurs in Europe, record the causes of overabundance and evaluate which set of indicators of ecological change is the most appropriate for monitoring and diagnosing overabundance in each scenario. Our review of 318 published papers revealed six contexts of wild ungulate overabundance in Europe (protected areas, hunting areas, forestry, arable farming, livestock farming and [peri]urban areas). In addition to population abundance, four sets of indicators of environmental change could be used to monitor overabundance within these contexts (impacts on habitats, impact on animal performance, increments in diseases and parasite loads, and increments in nuisance to humans). Nine species of ungulate were found to be overabundant. Red deer Cervus elaphus was the species most likely to be overabundant in the contexts of protected areas (detailed in 27% of papers on that context) and hunting areas (38%); roe deer Capreolus capreolus in forestry (28%); wild boar Sus scrofa in arable farming (60%), livestock farming (29%) and (peri)urban areas (38%). Our evidence shows that the diagnosis and monitoring of ungulate population overabundance via indicators of ecological change, and the management actions required to control these undesirable situations, are strongly context‐dependent.

Analysis of Roadkill on the Korean Expressways from 2004 to 2019

“…Korea is continuously expanding its road infrastructure to accommodate the growth of the population and industry. Ungulate populations are also increasing in many countries because of changes in the number of large predators, hunting and wildlife management practices [ 17 ], and landscape structure [ 18 , 19 , 20 ]. As this is thought to be a general trend, the frequency of roadkill in Korea is likely to increase.…”

Assessing red deer hunting management in the Iberian Peninsula: the importance of longitudinal studies

“…Current management schemes of big game in Europe normally lack proactive policies based on the understanding of population dynamics ( Vicente et al, 2019 ), which is essential to make ecological and socio-economic aspects compatible when exploiting the resource. Long-term hunting strategies that are not proactive may lead to high population densities and undesirable overabundance situations, causing adverse effects on the population itself as well as on other species and even on the economy as the use of the resource may become unsustainable ( Carpio, Apollonio & Acevedo, 2021 ; Valente et al, 2020 ).…”

Complementary Differences in Primary Production and Phenology among Vegetation Types Increase Ecosystem Resilience to Climate Change and Grazing Pressure in an Iconic Mediterranean Ecosystem

“…Free-ranging livestock breeding (ranching hereafter) is a widely used farming system in many areas around the world, often within natural areas of high conservation value, including protected areas. In ranching exploitations, livestock coexist with wild ungulate populations, which often show high population densities due to concomitant factors, such as hunting limitations and predator removal [16,17]. In these cases, understanding the combined effect of plant-herbivore interactions with both groups of grazers (wild and domestic) is essential if we are to understand their impacts on ecosystem structure, functioning, and resilience [18,19].…”