* Corresponding author
1 These authors contributed equally to
this work
Correspondence: Minghai Zhang Email:
zhangminghai2004@126.com
Abstract: The foraging strategies of sympatric ungulates with
similar ecological niches are important for understanding ecological
niche differentiation, resource utilization, competition, and
coexistence and for understanding the ecological impacts on plant
communities in the ecosystem. The behavior of the wapiti (Cervus
elaphus ) and Siberian roe deer (Capreolus pygargus ) foraging on
Japanese yew (Taxus cuspidata ) has affected its succession and
renewal in the northeastern forests of China, which has become an urgent
problem for the relevant departments. This study analyzed the foraging
strategies of the wapiti and Siberian roe deer on Japanese yew from July
2021 to January 2024 using field investigations and infrared camera
monitoring in the Muling National Nature Reserve, Heilongjiang Province,
China. It was found that the wapiti and Siberian roe deer have different
foraging strategies in terms of time, space, and behavior. Temporally,
they both preferred to forage for the saplings of the Japanese yew
during the winter season, the degree of overlap in foraging rhythms was
medium (Dhat1=0.67), and the diurnal foraging activity index
(D RAI) of the wapiti was larger than that of the
Siberian roe deer. Spatially, the suitable foraging habitat of the
Siberian roe deer was twice that of the wapiti, and their overlap was
low in the location and direction of saplings and the distance of the
seed tree. Behaviorally, the foraging intensity of the wapiti was heavy,
and Siberian roe deer was low. Foraging reduced the average primary
branch height, number of new branches, and length of lateral branches of
saplings, and the influence of the wapiti was significantly greater than
that of the Siberian roe deer. This study provides a scientific basis
for solving the conservation and management problems of the deer animals
foraging on Japanese yew and contributes to further understanding of the
competition-coexistence mechanism of sympatric species.
Keywords: Cervus elaphus ; Capreolus pygargus ;Taxus cuspidata ; foraging strategy; Kernel Density Estimation;
Maximum Entropy Model
INTRODUCTIONThe foraging strategy of ungulates is a key link between primary
production and food webs (Elsayed and Din, 2019). It influences the
structure and trends of changes in the biome (Shoener, 1987; Wang et
al., 2001), species distribution, resource utilization, and population
dynamics (Heleno et al., 2012; Tylianakis et al., 2010; Zanni et al.,
2021), and plays a major role in maintaining structural integrity and
balance (Ge et al., 2012; Kasiringua et al., 2020; Wang et al.,
2019a). Studies have found that the foraging of ungulates affects the
growth of plants, seriously leads to the failure of renewal, and has a
negative effect on interspecific competition (Bödeker et al., 2021;
Konôpka et al., 2021; Kamler et al., 2010; Klopcic et al., 2010;
Vacek, 2017), and spruce (Picea abies ) seedlings grow slowly
when foraged by roe deer (Capreolus capreolus ) (Bergquist et
al., 2003). Faced with this situation, plants will develop defense
mechanisms; for example, sheep (Ovis aries ) reduce their intake
when the flavonoid content of their food is too high (Sun, 2008).
Interactions between sympatrically distributed animals and plants have
been a classic proposition in evolutionary ecology, and the ecological
impacts produced by animals on plants have been a popular topic of
discussion in conservation biology and biodiversity conservation
(Feng, 2022). In northeastern China, Japanese yew (Taxus
cuspidata ) is a tertiary relict plant (Liu, 2007), which is a wild
and endangered class I national protected plant. The wapiti
(Cervus elaphus ) and Siberian roe deer (Capreolus
pygargus ) are both protected animals and are the main prey of the
Amur tiger (Panthera tigris ) and Amur leopard (Panthera
pardus orientalis ). The wapiti, Siberian roe deer, and Japanese yew
are, therefore, all the main protection species that need to be
focused on for the protection and management of national parks and
nature reserves. Previous studies have found that both the wapiti and
Siberian roe deer foraged on Japanese yew under environmental stresses
such as low temperatures, snow cover, and lack of food resources in
winter (Feng, 2022). The Japanese yew accounts for 13% of the winter
food composition of the wapiti, which leads to significant damage to
the saplings (Zhu et al., 2019). As a result, their number and
distribution range has declined sharply (Diao et al., 2020; Yang,
2018). On the other hand, the number of ungulates, such as the wapiti,
is also decreasing in reserves due to human activities such as
long-term forest logging, illegal poaching, and road construction in
the past (Dixon et al., 2021; Sarula et al., 2019). Protecting
wildlife like the wapiti, without affecting the succession and renewal
of the Japanese yew forests has become an urgent problem for the
management department of nature reserves. This study, therefore,
analyzed the impacts of these two ungulates on Japanese yew by
comparing their temporal and spatial strategies, and behavioral
characteristics, to provide a scientific basis for solving the problem
of their protection and management. The results not only contribute to
further understanding of the competition-coexistence mechanism of
sympatric species but also enrich the study of animal and plant
interaction and co-evolution.
MATERIALS AND METHODS2.1 Study areaThe study area is located in the Muling National Nature Reserve, in
the southern part of the Laoyeling, in the northern part of the
Changbai Mountain (130°00′–130°28′E, 43°49′-44°06′N). The south is
bordered by the Tianqiaoling Forestry Bureau of Jilin Province, the
east is bordered by the Suiyang Forestry Bureau of Heilongjiang
Province, and the west, north, and northeast are connected with the
Gonghe Management Office, Shuangning Forest Farm, and Yangmuqiao
Forest Farm of Muling Forestry Bureau, with a total area of 356.48
km2 (Feng, 2022). The mountains in this area are
low, with altitudes ranging from 500m to 900m, and the landforms are
distributed in bands. The climate is the typical temperate continental
climate with an average annual temperature of approximately -2℃. The
rainy season is short, and precipitation is concentrated, with an
average annual rainfall of 514 mm and an annual frost-free period of
130 d (Tian et al., 2022). The forests in the reserve are primarily
coniferous, broad-leaved forests, mixed coniferous and broad-leaved
forests, and thickets, with 839 plant species belonging to 113
families and 373 genera. The dominant species are red pine
(Pinus koraiensis ), purple linden (Tilia amurensis ), and
red-barked spruce (Picea koraiensis ). There are 42 vertebrate
species belonging to six orders and 14 families, represented by the
Amur tiger, Amur leopard, wapiti, sika deer (Cervus nippon ),
Asian black bear (Ursus thibetanus ), and wild boar (Sus
scrofa ).2.2 Methods2.2.1 Field investigation
Areas with a relatively concentrated distribution of Japanese yew were
selected for field investigations every winter from 2021 to 2024. The
saplings were divided into foraging and control groups. During the
survey, the saplings that were foraged on were labeled and their height,
length of lateral branches, number of branches foraged, total number of
branches, and information about the surrounding environment were
recorded. Normal saplings were selected as controls in the corresponding
areas, and the plant height and number of branches were recorded. The
height of the primary branch growth, the number of new branches, and the
length of lateral branch growth for each sapling were recorded every
summer from 2021 to 2024.
The footprints and foraging traces were combined to distinguish saplings
foraged by the wapiti or the Siberian roe deer. A total of 1947 foraging
traces were observed. Among them, 1,235 were of the wapiti and 712 of
the Siberian roe deer.
2.2.2 Infrared camera monitoring