In recent years, keeping animals indoors has become a popular rearing system in many countries where there is a high population density and lack of land to graze animals. However, this frustrates animals by depriving them of opportunities for many behaviors. To solve these problems, environmental enrichment was introduced to animal welfare science. It is thought to be an alternative means to contribute to animal welfare. It focuses on the biological functions of the animals and helps them to cope with stressors in their surroundings, prevent frustration, and express more normal behaviors. In this review, several elements of environmental enrichment and how they affect animal welfare are discussed. First, we discuss natural suckling and group rearing, both of which allow animals to perform social behaviors with other individuals. Second, we summarize behavior-stimulating tools such as brushing, scratching/rubbing arch devices, and bedding materials. Finally, space allowance as physical enrichment is discussed. Now that animal welfare science focuses on how to improve animal welfare and prevent stress, rather than reducing stress when animals have already suffered, therefore more attentions should be paid to studies on environmental enrichment. Introduction In recent years, keeping animals indoors has become a leading rearing system in many countries where there is a high population density and lack of land to graze animals. Rearing animals indoors provides many advantages, such as protecting animals from extreme weather conditions and parasite infections and reducing environmental pollution. However, it also frustrates animals, resulting in a change in behavioral and physiological indicators. For example, disturbed behavior, such as repeated tail-biting (Schrøder-Petersen and Simonsen, 2001) in pigs, and severe feather-pecking and vacuum nest-building in chickens (Jensen, 1993), occurs during unnatural life conditions. As to physiology, it has been reported that cortisol concentration is increased by social disruption (Adeyemo and Heath, 1982), restraint (Lefebvre et al., 1990), and transport (Palme et al., 2000). Cattle with high levels of serum cortisol spend less time ruminating and vocalize more than those with low levels of cortisol (Bristow and Holmes, 2007). Until recently, most welfare assessments were conducted when animals were already under stressful conditions. However, studies of how to improve welfare and keep animals in a comfortable condition and prevent stress should be paid more attentions than studies on how to reduce stress after it has occurred. Duncan and Olsson (2001) argued that freedom from the state of suffering is assured by providing for environmental requirements, while the establishment of pleasurable states requires environmental enrichment. Environmental enrichment is widely used to help animals cope with stress in indoor rearing. On the other hand, environmental enrichment is an alternative way to contribute to animal welfare. It focuses on the animals’ biological functions, helps animals to cope with stressors in their surroundings, prevents frustration, and allows animals to express more normal behaviors (Newberry, 1995). Bloomsmith et al. (1991) stated that environmental enrichment can be divided into ve categories: social, occupational, physical, sensory, and nutritional. Therefore, environmental enrichment can improve animal welfare from
Decayed wood provides regeneration microsites for a variety of tree seedlings, whereas the mechanisms of species-specific preferences for decayed wood, their decay types, and soil are poorly known. To evaluate the effects of chemical and biological characteristics of the substrates on seedling preference, I investigated the biotic and abiotic effects of different substrates on the aboveand belowground growth of seedlings of 4 tree species commonly occurring in post-Pine Wilt Disease (PWD) forests. Seedlings were grown in microcosms including autoclaved or non-autoclaved substrates (3 types: white-rotted wood, brown-rotted wood, and soil) for 4 months. After retrieval, the aboveand belowground growth of the seedlings was measured. Pinus densi ora seedlings experienced greater growth in nons-autoclaved rather than autoclaved substrates; however, growth was affected to a lesser extent by the differences in substrates. In contrast, Cryptomeria japonica seedlings experienced greater growth in soil than in woods; however, growth was not affected by autoclaving. Aboveground growth of Clethra barbinervis seedlings was greater in soil and autoclaved brownrotted wood than in other wood substrates. The growth of Eurya japonica seedlings was greater in soil than in woods. Seedlings of the 3 species, excluding C. barbinervis, showed plasticity in the shoot/root ratio against substrate difference. The relative importance of biotic and abiotic factors for the aboveand belowground growth of seedlings differ among tree species, which may partly explain species-dependent preferences for different microsites on the forest oor when regenerating in post-PWD forests. Introduction Microsite heterogeneity plays an important role in plant population dynamics and species diversity maintenance in forest ecosystems (Harmon and Franklin 1989; Nakashizuka 2001). Different tree species favor speci c microsites for seedling regeneration, reflecting their life-history traits associated with physiological and morphological responses to abiotic and biotic environmental conditions (Leck and Outred 2008). Allocation to aboveand belowground growth is one of the most conspicuous traits characterizing the initial responses of seedlings to their environments (Kohyama and Grubb 1994; Doi et al. 2008). Thus, it is important to determine allocations of seedlings to aboveand belowground growth for understanding their preferences pertaining to forest microsites. Among the microsites on forest floors, coarse woody debris (CWD) provides important refuges for seedling establishment in various forest ecosystems (Fukasawa 2012). Although CWD generally contains relatively lower concentrations of nutrients compared with soil (Goodman and Trofymow 1998; Baier et al. 2006), it can contain greater concentrations of nutrients compared with soil in some cases (Takahashi et al. 2000; Fukasawa 2015a). Furthermore, the nature of microbial communities inhabiting CWD, particularly the low level of soil-borne pathogens, often contributes to good growth performances of pathogen-susceptible
The current status of conservation activities on the Korean rare and endemic species was reviewed with a special reference to the Korea National Arboretum (KNA). In the Korean peninsula, there are 4,172 plant taxa including 360 endemics and 571 rare plants categorized at the national level by the IUCN criteria: EW 4, CR 112, EN 199, LC 70, and DD 112. The KNA has established various in- and ex-situ conservation programs in practice for GSPC goals since 2010. In order to improve the conservation activities, the KNA has managed specialized research projects as well as networking programs with other local governmental arboreta and NGOs in Korea. The main purposes of the research projects are to (1) survey, update, and evaluate the conservation and genetic status of Korean populations of rare endemic plants; (2) formulate an urgent conservation strategy; and (3) monitor the endangered populations based on the latest and accurate ecological and biological information. For the ex-situ conservation, the KNA has secured and propagated seeds and living collections of rare and endemic plants, and as a result, the KNA conserves about 70% of Korean rare plants as living collection and propagules. A total of nine conservation fences have been installed and monitored by the KNA as part of in-situ conservation. In addition, the KNA has carried out a re-introduction program for rare plants such as epiphytic orchids in natural habitats by developing propagation techniques with accurate genetic tags. The KNA also promotes training and international cooperation programs for the in-and ex-situ conservation activities for the East Asian biodiversity.
