Red deer (Cervus elaphus) in the Chornobyl biosphere reserve: monitoring, ecology, and behaviour

Abstract

Data on the number, monitoring system, ecology, and behaviour of red deer are presented. The most effective survey methods of the number and spatial distribution of deer turned out to be the survey of the number per roar (during the mating season) and transect survey for piles of faeces. The most significant factors limiting the population were established: wolf predation, the spread of invasive tree species, clonal marten grass, weak recovery of heather on the fires, and changes in behaviour (digging wells-watering holes). Under the conditions of the Chernobyl Reserve, the species is an effective ecosystem engineer able to a certain extent to restrain undesirable phenomena of ecosystem development. But this species is not able to independently restore degraded ecosystems, and in the Chernobyl Reserve, special projects are needed to restore natural forests, grazing areas for ungulates, and degraded ecosystems. Photos of antlers of adult deer makes it possible to reliably identify them. The specific shape of the antlers is preserved in the following year with the possibility of identification. The process of deer reintroduction in the Chornobyl Reserve, after the phase of intensive population growth, entered a state of dynamic equilibrium of the predator-prey system. After the fall in the number of wild boars (Sus scrofa) in 2015 the pressure of wolf predation probably increased. The current abundance of deer in the exclusion zone fluctuates around 30% throughout the year and is 3.8–2.6 thousand individuals with a population of about 3.4 thousand individuals during rut. Foraging conditions for deer and other herbivores slowly deteriorate over time due to the overgrowth of fallows with pine (Pinus sylvestris), expansion of invasive trees and clonal marten grass (Calamagrostis epigejos). Fires on a large area with piles of wood do not contribute to the creation of mosaic productive biotopes for deer. In the future, the number of deer and other herbivores may increase in the case of successful implementation of re-wilding projects, restoration of heather wastelands, natural forests, reduction of the spread of martens, introduction of a system of targeted fires to create patches of early successional vegetation. The creation of a scientific hub in the Chernobyl Exclusion Zone, the involvement of volunteers in monitoring work, and the development of ecotourism will contribute to the strengthening of technical capabilities of conducting fieldwork, attracting volunteers and funding for restoration projects.