In Situ and Ex Situ Conservation: Complementary Approaches for Maintaining Biodiversity

IJRES 4 (2017) 1-12 ISSN 2059-1977

In situ and ex situ conservation: Complementary approaches for maintaining biodiversity

Haileab Zegeye

Department of Biology, Faculty of Natural and Computational Sciences, Debre Tabor University, P. O. Box 272, Debre Tabor, Ethiopia. E-mail: [email protected]; [email protected].

Article History ABSTRACT Received 30 October, 2016 This review highlights the threats to biodiversity and the conservation methods Received in revised form 09 from a global perspective. Biodiversity includes a number of different levels of December, 2016 Accepted 12 December, 2016 variation in the natural world. It can be measured at various levels. The most commonly used measures of biological diversity are genetic diversity, species Keywords: diversity and ecosystem diversity. At spatial scales, biodiversity can be Biodiversity, measured as alpha diversity, beta diversity, gamma diversity and delta diversity. Conservation, Biodiversity also includes cultural diversity (biocultural diversity). Biodiversity Sustainable use, has environmental, cultural, social, economic, medicinal, scientific, educational Threats. and aesthetic values. However, biodiversity is being lost at an alarming rate due to natural and more importantly anthropogenic factors. The threats to biodiversity are agricultural expansion, overexploitation, urbanization and industrialization, pollution, fire incidence, exotic species, genetically modified organisms (GMOs) and global climate change, which are all driven by human population growth. The conservation of biodiversity is achieved by two approaches – in situ and ex situ. In order to ensure the maintenance of biodiversity, there is a need to employ complementary in situ and ex situ conservation. There is also a need to prioritize ecosystems, species and populations for conservation actions. Moreover, promotion of indigenous resource management systems and practices, involvement of local people in conservation planning and endeavours, development of appropriate benefit- sharing mechanisms, awareness creation, promotion of the involvement of all relevant stakeholders and provision of adequate human, financial and physical resources for conservation efforts are important measures that should be taken in order to ensure the conservation, management and sustainable use of Article Type: biodiversity. Above all, biodiversity conservation requires a multidisciplinary Review approach, and needs to be a continuous endeavour. ©2017 BluePen Journals Ltd. All rights reserved

INTRODUCTION

The Earth holds a vast diversity of living organisms natural world. The most commonly used measures of (plants, animals, microorganisms) and an immense biological diversity are genetic diversity, species diversity variety of ecosystems. Biological diversity or biodiversity and ecosystem diversity. These three main components is the variability among living organisms from all sources of biodiversity are inextricably interlinked. including, inter alia, terrestrial, marine and other aquatic Genetic diversity is the variation in the genetic makeup ecosystems and the ecological complexes of which they of organisms (nucleotides, genes, chromosomes). It are part; this includes diversity within species, between refers to the genetic variability between species and species and of ecosystems (CBD, 1992). Biodiversity within species (that is, the genetic variation between includes a number of different levels of variation in the individuals within populations and between populations

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within species). In a broader sense, genetic diversity this is associated with the uneven distribution of exists at various taxonomic levels such as subspecies, environmental factors, human population and disturbance species, genera, families, orders, phyla, kingdoms and regimes. As a result, some areas are rich in biodiversity domains. Species diversity is the diversity of species in a while others are poor. Those areas with spectacularly given area. Species diversity contains two quite distinct high species diversity and endemism have been concepts – richness and evenness (Krebs, 1989; Begon regarded as biodiversity hotspots (Myers et al., 2000; et al., 1996; Barnes et al., 1998). Species richness refers Gaston, 2010; Laurance, 2010). Myers et al. (2000) to the number of species in a given area. It is the most identified 25 biodiversity hotspots worldwide, which they fundamental component and commonly used measure of proposed for conservation priorities. These have been biological diversity. Species evenness or equitability is revisited, and today there are 34 biodiversity hotspots in the relative abundance of species in an area. Relative the world. abundance can be measured by number of individuals, Biodiversity has environmental, cultural, social, cover, biomass, productivity, or any measure that economic, medicinal, scientific, educational and aesthetic quantifies the importance of the species. Ecosystem values. Ecosystems provide diverse goods and services: diversity is the diversity of ecosystems in an area. It repository of genetic resources; soil formation and refers to the variety of terrestrial and aquatic ecosystems. fertility; erosion control; nutrient cycling; hydrological Biodiversity is dynamic; it varies in space and time. At cycle regulation; drought and flood mitigation; watershed spatial scales, biodiversity can be measured as alpha protection; carbon sequestration; climate regulation; diversity, beta diversity, gamma diversity and delta siltation prevention; pollination and seed dispersal; pest diversity (Bisby, 1995; Rosenzweig, 1995; Ricklefs and and disease control; pollution control; products (food, Miller, 2000; Lomolino et al., 2006). Alpha diversity (local medicines, fodder, wood, fibers, etc.); and recreation diversity) is the diversity of species at local spatial scales. (Troy and Bagstad, 2009; Gaston, 2010; Sekercioglu, It refers to the number of species in a single site or 2010; FAO, 2014). As such, biodiversity has fundamental habitat (WCMC, 1992; Rosenzweig, 1995; Ricklefs and importance in maintaining environmental stability and Miller, 2000), or the number of species occurring within improving human wellbeing. an area of a given size (Bisby, 1995). It is a measure of within-area diversity. Beta diversity, also known as species turnover or differentiation diversity, is the degree THREATS TO BIODIVERSITY of change in species composition across a region or landscape along major environmental gradients such as The world human population is increasing at a faster rate. latitudinal, altitudinal and ecological gradients (WCMC, The world population reached about 7.4 billion by 2015, 1992; Bisby, 1995). It is a measure of the difference in and is projected to reach about 11.2 billion by 2100 diversity from one habitat or area to the next. Beta (Ortiz-Ospina and Roser, 2016). More people means diversity is a measure of between-area diversity. Gamma more resources are depleted, more land is developed, diversity (regional diversity) is the species diversity at and more pollution is created. The demand for resources regional spatial scales. It is the total number of species in rises with increasing human population. Human all habitats within a region (Rosenzweig, 1995; Ricklefs population growth causes changes in land and water use and Miller, 2000). Like alpha diversity, gamma diversity is patterns, which directly or indirectly affect biodiversity. also a measure of within-area diversity. However, it most Habitat destruction and overexploitation of resources are often refers to overall diversity within a large region associated with increase in human population, and (Bisby, 1995). Delta diversity is the degree of change in constitute a major threat to biodiversity (Mooney et al., species composition between large geographical areas 1995a). Overexploitation causes loss of populations, (Lomolino et al., 2006). Like beta diversity, delta diversity species and ecosystems. Human population growth and is between-area diversity. the increasing consumption of natural resources are the Biodiversity also includes the human dimension and main forces driving the global transformation of the this aspect of biodiversity is referred to as cultural biosphere (Heywood and Baste, 1995). Human use of diversity (Heywood and Baste, 1995), or more recently resources has led to simplification of ecological systems biocultural diversity (Loh and Harmon, 2014). Most and reduction in biodiversity. The highest rate of human biodiversity and landscapes are the products of nature population growth on Earth prevails in Sub-Saharan and culture. There are innumerable interactions between Africa, and the region is plagued by overexploitation of humans and biodiversity. Indeed, humans interact with all natural resources (Ricklefs and Miller, 2000). levels of biodiversity. The different cultural dimensions in Globally, humans (Homo sapiens) are the dominant various parts of the world have played a major role in the species influencing biodiversity. The influence of humans conservation, management and sustainable use of on the Earth’s biological systems is increasing biodiversity. exponentially (Heywood and Baste, 1995). The world’s Biodiversity is unevenly distributed on Earth. In fact, terrestrial and aquatic ecosystems have been so

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significantly modified by human activities. The increased expansion (farmland expansion, overgrazing) has human interference has resulted in destruction of the resulted in the conversion of forests, woodlands, environment and, consequently, disruption of evolu- savannahs, grasslands and wetlands into farming and tionary and ecological processes. Tropical regions, which grazing lands. The increased demand for agricultural harbor the greatest species diversity and are the richest lands has caused habitat loss and fragmentation, and centres of endemism and thereby possess many consequently reduction in biodiversity. Overgrazing has biodiversity hotspots, are manifesting the highest rates of resulted in severe degradation of rangelands and bush habitat loss (Laurance, 2010; Sodhi and Ehrlich, 2010). encroachment (Mooney et al., 1995a). Therefore, it is Tropical forests are disappearing at up to 130,000 km2 important to take measures that reduce agricultural per year (Laurance, 2010). The Atlantic forests of Brazil expansion into natural ecosystems. and rainforests of West Africa, both of which are examples of biodiversity hotspots, have been severely reduced and degraded. The most rapid decline in Overexploitation biodiversity is now happening in the tropics, the part of the world with the greatest diversity (Loh and Harmon, Biodiversity is under heavy threat from anthropogenic 2014). overexploitation. In an increasingly human-dominated As a result of heedless human actions, biodiversity is world, where most of us seem oblivious to the liquidation being lost at an alarming rate (Heywood and Baste, 1995; of Earth’s natural resource capital, exploitation of Jeffries, 1997; Engels and Engelmann, 2002). There is a biological populations has become one of the most rapidly accelerating loss of populations, species and important threats to the persistence of global biodiversity ecosystems. The vast majority of populations and (Peres, 2010). Humans assess the surface of the Earth species of plants and animals are in decline, and many and even probe into the inner strata to remove resources are already extinct. For instance, of the known 400,000 or for use, which is unsustainable. The economies of both so higher plant species, 148,000 (37 %) are threatened developing and developed nations still depend heavily on (Pimm and Jenkins, 2010). Escalating human population primary extractive industries, such as logging, hunting growth and consumption of resources have precipitated and fishing. Human exploitation of biological commodities an extinction crisis – the “six mass extinction,” which is involves resource extraction from the land, freshwater comparable to past extinction events such as the bodies or oceans, so that wild plants, animals or their Cretaceous-Tertiary mass extinction 65 million years ago products are used for a wide variety of purposes ranging that wiped out all the dinosaurs (Sodhi and Ehrlich, from food to medicines, fuel, shelter, fiber, construction 2010). They pointed out that unlike the previous materials, household and garden items, pets and extinction events, which were attributed to natural cosmetics. Overexploitation occurs when the harvest rate catastrophes including volcanic eruptions, meteorite of any given population exceeds its natural replacement impact and global cooling, the current mass extinction is rate, either through reproduction alone in closed exclusively humanity’s fault. Recent and current rates of populations or through both reproduction and immigration extinction are 100 times faster than the background rate, from other populations. while future rates may be 1,000 times faster (Pimm and Many species are relatively insensitive to harvesting, Jenkins, 2010). remaining abundant under relatively high rates of offtake, The Earth has been taking care of us while most of us whereas others can be driven to local extinction by even admit that we have not been too kind to our planet the lightest levels of offtake (Peres, 2010). A number of recently. Human damage to the Earth is wide in scope. species are threatened by unsustainable logging in forest The threats to biodiversity (that is, drivers of biodiversity regions, overhunting of wildlife in many terrestrial loss) are agricultural expansion, overexploitation, ecosystems, overfishing in aquatic ecosystems, or many urbanization and industrialization, pollution, fire other forms of unsustainable extraction. Humans are incidence, exotic species, GMOs and global climate depleting the Earth’s biodiversity at a faster rate than change. before and thereby depriving future generations.

Agricultural expansion Urbanization and industrialization

Globally, agriculture is the biggest cause of habitat Urbanization, industrial development and road construc- destruction (Barlow and Tzotzos, 1995; Laurance, 2010). tion affect biodiversity. The loss of habitat due to The soil on farmlands has been eroded away or paved development of infrastructure causes reduction in over, and farmers increasingly are forced to turn to biodiversity. Urbanization results in loss of natural marginal lands to grow more food. There is agricultural vegetation and thereby decline in wildlife. An important expansion into ecologically fragile areas. Agricultural consequence of urbanization is the increased demand on

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food production to feed the urban population. Further Here it is important to note that native species can also more, urban areas are the major sources of pollutants become invasive. (McNeely et al., 1995). Exotic species disrupt evolutionary and ecological processes. They often have major impacts on native species and ecosystems, and may be considered Pollution ecological disasters (McNeely et al., 1995; Mooney et al., 1995b). Exotic species compete aggressively for local Discharge of domestic and industrial wastes and unwise resources and affect the growth and reproduction of use of agricultural chemicals (fertilizers, insecticides, native species. pesticides, herbicides) have caused pollution of air, water Ecosystems with relatively low species richness such and soil. As a result of discharge of wastes from heavily as island and temperate ecosystems are vulnerable to populated and industrialized areas, the nutrient content of introduced species. Introduced species can be disastrous marine and other aquatic ecosystems has increased to island flora and fauna. Hawaiian Islands have lost significantly (Mooney et al., 1995a). The increased more than half of their original endemic species due to nutrient load has caused changes in their physical, introduced plants and animals (IUCN/UNEP, 1986). For chemical and biological properties. Pollution reduces or the Hawaiian Islands, almost 50% of the plant species, eliminates populations of sensitive species (Kaya and 40% of birds, most freshwater fishes, and 25% of insects Raynal, 2001). The negative impacts of pollution on are introduced (Simberloff, 2010). Islands of Africa like biotas can be considerable (McNeely et al., 1995). Mauritius, Reunion and Rodrigues have suffered from a devastating wave of extinctions in historic times, much of which can be attributed to introduced species (IUCN, Wildfires 1990). The introduction of new species into aquatic Fire is both an ecological and anthropogenic factor. Fire ecosystems, especially freshwater ecosystems, can has both positive and negative impacts on the produce considerable effects (Mooney et al., 1995b). For environment. Many species in fire-prone ecosystems are example, the introduction of the Nile perch (Lates not only fire-tolerant, but depend on fire to complete their niloticus) into Lake Victoria has severely affected the life cycles and to retain a competitive edge in their Lake’s entire fishery (Ricklefs and Miller, 2000). It was a environment. The benefits of fire to the species include purposeful introduction for subsistence and sports fishing, increased resource availability associated with the and has become a great disaster. destruction of both living and dead biomass, nutrient-rich Many exotic species have significant impacts on the ash, high light conditions, and seed germination. For environment, economy and human health. Invasive alien instance, the seeds of Acacia species and other legumes species cause myriad sorts of conservation problems. are stimulated to germinate by fire. On the other hand, Therefore, there is a need for a careful assessment of there are fire-sensitive species and ecosystems. Fire has past experiences to provide general, scientifically based caused great devastation of ecosystems in various parts policies and guidelines about species introductions, of the world, for example, Australia. In recent years, taking into account ecological and economic considera- climate change has increased the risk of fire. The effects tions. of fire on biodiversity have been highlighted by Bowman and Murphy (2010). Genetically modified organisms (GMOs)

Exotic species Biotechnology has wide applications in agriculture, health, industry and the environment. Biotechnology Exotic species are species that are introduced to an area provides a variety of applications for understanding of outside their normal range through intentional or biodiversity. It has also become important for unintentional human assistance (Hawksworth and Kalin- conservation and sustainable use of biodiversity. Arroyo, 1995). Exotic species are also known as alien However, modern biotechnology can affect biodiversity in species, introduced species and non-native species. various ways. GMOs that result from genetic engineering Most exotic species are harmless or beneficial in their may have adverse impacts on biodiversity and human new environments. However, some exotic species health (Barlow and Tzotzos, 1995). GMOs affect become invasive and disrupt the functioning of evolutionary and ecological processes. The splicing of ecosystems. Not all introduced species become invasive, genes into other organisms from unrelated species however (Simberloff, 2010). Many plant species causes genetic pollution (Barlow and Tzotzos, 1995). introduced as ornamentals persist in gardens with human Furthermore, the transgene may transfer to other related assistance but cannot establish in less modified habitats. species, and this can have significant impacts on the

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genetic makeup of the species (McNeely et al., 1995). climate change will significantly threaten levels of GMOs may become weeds, competitors of native biodiversity with concerns over the subsequent loss of species, produce pathogenic or toxic agents, or disrupt genetic resources and ecosystem goods and services. It energy flow and nutrient cycling. Enhanced ability of brings complex changes in species composition and GMOs to invade natural habitats may lead to loss of interactions, and may result in a significant reduction in populations and species, thereby reducing biodiversity. biodiversity (Heywood and Baste, 1995; Mooney et al., Furthermore, the widespread monoculture of genetically 1995a; Ricklefs and Miller, 2000). Ecosystems are improved crops leads to replacement of traditional crop vulnerable to climate change with the risk of extinction of varieties and landraces and presents a potential threat to certain species. agrobiodiversity. The most recent models based on a temperature rise of Therefore, there is a need for appropriate safeguards to 2-3°C over the next 100 years suggest that up to 50% of ensure safe applications of biotechnology. The use and the 400,000 or so higher plant species will be threatened release of GMOs require appropriate policy, regulation, with extinction (Bramwell, 2007). Prediction models have management, control and monitoring in order to ensure shown that the humid tropical ecosystems will be under adequate safety regarding the potential impacts on the severe threat from climate change. The wet tropical environment and human health. It requires risk forests of the Amazon Basin will all but disappear with assessment. Risk reduction is achieved mainly by huge losses of biodiversity (Nobre, 2004). The tropical confinement (Barlow and Tzotzos, 1995). Past forests of West and Central Africa will be seriously experience with GMOs is often a good guide for best affected and that between 50 and 80% of species will management and practice. have their range severely reduced, many to the point of extinction (Lovett et al., 2005). The impact of climate change on biodiversity of the tropical rainforests of Global climate change northern Queensland, Australia is likely to be very serious and could be catastrophic under some scenarios; many The Earth’s climate is rapidly changing as a result of species of plants and animals are at highly increased risk increases in the concentrations of greenhouse gases of extinction (Krockenberger et al., 2004). All boreal (GHGs) in the atmosphere mainly caused by human ecosystems are vulnerable to climate change, and boreal activities, particularly burning of fossil fuels, agriculture, forests in particular could decline if climatic conditions deforestation and other land use changes (Wigley, 1999; become significantly warmer or drier (Laurance, 2010). Stern, 2006; IPCC, 2007). Since 1900, the global Climate change models also predict that there will be average surface temperature has risen by 0.76°C (IPCC, drastic, rapid and chaotic shifts in the distribution of 2007; Deeb et al., 2011). The Intergovernmental Panel species and habitats across the globe (Pritchard and on Climate Change (IPCC) asserts that continued Harrop, 2010). For instance, the Quiver tree (Aloe emissions of GHGs at or above the current rates would dichotoma) – the iconic desert species – is undergoing cause an increase in the global average surface population collapse in the northern part of its geographic temperature by 1.8 to 4.0°C by 2100 (IPCC, 2007). On range, in Namibia, and active expansion in the cooler the other hand, precipitation has showed different spatial southern parts, in Namaqualand (Foden, 2002). and temporal patterns (increases or decreases) in Therefore, there is a need to take an urgent action to different regions of the world. protect biodiversity from the threats of climate change. Global climate change is one of the greatest challenges Steps to mitigate and adapt to new and often dramatic the world is facing today. Climate change has led to sea climatic conditions are being widely debated and level rise (due to melting of ice and glaciers and encouraged by politicians and the media. Environmen- expansion of sea water resulting from rising talism is fashionable but still the value of maintaining temperatures), changes in global precipitation patterns, biodiversity is not given the attention it deserves. increased frequency and intensity of extreme weather events (droughts, floods, heat waves, cold snaps, storms/hurricanes, etc.), shifts in the distribution of CONSERVATION APPROACHES species and ecosystems, expansion of desertification, increased intensity and frequency of wildfires, decline in There are several methods for conservation of or loss of biodiversity, increased environmental pollution, biodiversity. The different conservation methods can be decline in agricultural production and productivity, water broadly divided into two approaches – in situ and ex situ. scarcity, increased incidence of pests and diseases, and In situ (on-site) conservation is the conservation of human migration and conflict. There are observed and genetic resources within the natural ecosystem in which expected impacts of climate change. they occur, while ex situ (off-site) conservation is the Climate change is quickly emerging as a key issue in conservation of genetic resources outside the natural the battle to preserve biodiversity. Human-induced ecosystem in which they occur. Each of in situ and ex situ

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2 Most effective Single use wildland ____ Scientific reserves/strict nature reserves management

In situ Multiple use ____ National parks, natural monuments, wildland managed nature reserves, protected management landscapes, resource reserves, anthropological reserves, multiple use management areas

Areas other than ____ Converted land managed for genetic wildlands diversity

Whole organism ____ Botanical gardens, zoos Ex situ Organism parts ____ Sperm, egg and embryo banks; organ banks; seed and pollen banks; genebanks; tissue culture 3 Least effective

Figure 1. The roles of in situ and ex situ conservation. Source: Whitmore (1990).

conservation can be subdivided as shown in Figure 1. costs, risks and research needs of ex situ conservation In situ and ex situ conservation are mutually reinforcing are significantly higher than that of in situ conservation. and complementary approaches (Miller et al., 1995; Due to the complexity of biodiversity, rapid loss of Jeffries, 1997; Wolf, 1999; Wyse Jackson and biodiversity, and increased realization of the importance Sutherland, 2000; Pritchard and Harrop, 2010). In order of undertaking cost-effective programmes, developing to ensure the conservation of the widest possible range realistic and viable strategies and setting priorities for of biodiversity and minimize the risk of genetic erosion, effective conservation and management of genetic the various conservation methods should be combined in resources will always be necessary (IPGRI, 1993; Miller an integrated approach (that is, integrated biodiversity et al., 1995; Kigomo, 1999; Wolf, 1999; Coates and conservation). Indeed, there is no universal method that Atkins, 2001; Engels and Engelmann, 2002). There is a can cover all conservation purposes. The development of need for identification of action priorities both in complementary conservation strategies in which different geographical space and biological importance (Jarvis et conservation approaches and methods are being al., 2002). Indeed, the choice of suitable conservation combined helps to achieve the most stable and cost- methods depends on the objectives of the envisaged effective conservation effort for a given genepool under genetic conservation and the ecological requirements of locally prevailing conditions (Wyse Jackson, 1998). Here the species in question. Conservation is a dynamic it is important to note that both in situ and ex situ process, and requires continuous evaluation based on conservation have merits and demerits. Furthermore, the emerging issues and newly acquired research findings.

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In situ conservation 1995; Jeffries, 1997; Wolf, 1999). It is necessary to provide adequate human and financial resources in order In situ conservation maintains species in dynamic to ensure the effectiveness of protected areas for relationships with the habitat and allows gene flow and maintaining biodiversity. In addition, the development and geographical distribution (Edwards and Kelbessa, 1999). management of protected areas needs the participation Ecosystems, species and populations are dynamic; they of the local people in making decisions and undertaking are variable in space and time. In situ conservation conservation measures. The conservation of biodiversity allows evolutionary and ecological processes to take in protected areas requires the generation of appropriate place and promotes genetic variability and adaptability of incentives from international, regional and national species to changing environmental conditions. Therefore, agencies for resource users both in and around the the conservation of biodiversity is best achieved in protected areas. It is important to provide incentives of natural ecosystems (WCMC, 1992; Heywood and Baste, various forms (for example, tax breaks, subsidies) for the 1995). The in situ conservation approach allows the local people in order to ensure the sustainability of conservation of a large amount of genetic diversity, protected areas. There is a need to have appropriate species diversity and ecosystem diversity in a very mechanisms for sharing benefits that are generated from extensive and cost-effective manner (Wolf, 1999). The the conservation and sustainable use of biodiversity costs, risks and research needs of in situ conservation within protected areas. For instance, in Cameroon and are generally low. However, in situ conservation is not Zimbabwe, the involvement of local people in feasible in areas with high environmental and human conservation activities and sharing of benefits derived pressures. The reconciliation of the conservation from the protected areas have been found most effective activities with immediate and basic human needs, for (Jeffries, 1997). However, in many African countries, example, for agricultural land, is often difficult. Species or protected areas have failed to meet their conservation populations conserved in situ may be susceptible to objectives mainly because of the exclusion of local calamities or deliberate damages (for example, fire) people from participation and lack of appropriate depending on the level of disturbance. As such, in situ mechanisms to provide incentives (Jeffries, 1997; conservation is not feasible for threatened species due to Zegeye, 2004). escalating human pressure. Moreover, in situ In many developing countries with rich tropical conservation may be impaired by lack of direct influence biodiversity, government agencies responsible for the due to ownership. In situ conservation methods include management of protected areas lack the necessary the different protected area systems, and on-farm technical capacity to stem biodiversity loss effectively conservation in which cultivated plants and domesticated (Rao and Ginsberg, 2010). Managers of protected areas animals are conserved in the agroecosystems where they often have limited access to the vast and dynamic body have been developed and utilized. of knowledge and tools in conservation science. There is an urgent and critical need to transfer the advances in conservation science to individuals and institutions in Protected area systems biodiversity-rich countries.

Biodiversity conservation is most often achieved by establishment and management of protected areas. On-farm conservation Protected areas are geographically delineated areas that are designated or regulated and managed to achieve On-farm conservation is the conservation of crops and specific conservation objectives (Miller et al., 1995). their wild relatives, livestock, and the agroecosystems in Protected areas should have sufficient size that can allow which they occur. Agroecosystems include homegardens, the maintenance of a given ecosystem or species (IUCN, crop fields, agroforestry systems, fallow fields and 1990; Jeffries, 1997; Wolf, 1999). In addition, there is a grazing lands. Agricultural biodiversity, or agrobiodiver- need to have protected area systems that are sity, is that component of biodiversity that contributes to representative of major landforms and ecosystems. food and agricultural production. In situ conservation on- Protected areas play a great role in the conservation of farm is important for maintenance of agrobiodiversity. biodiversity. They have environmental, social, economic, Indigenous resource management systems and scientific, educational and aesthetic values. There are agricultural practices play an important role in the different forms of protected areas based upon maintenance and diversification of domesticated plants management objectives (for details refer to IUCN, 1992; and animals (McNeely et al., 1995). Low-input agricultural WCMC, 1992; Hawksworth, 1995; Miller et al., 1995). systems are important sources and custodians of The sustainability of in situ conservation in protected agrobiodiversity. Farmers and pastoralists maintain a areas depends on the long-term protection and effective- tremendous diversity of crop and livestock varieties ness of management (IUCN, 1990, 1992; Miller et al., around the world. Indigenous knowledge, skills and

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practices of farmers play an important role in the genebanks with the aim of preserving rare and conservation and management of agricultural bio- threatened plants and making the material available for diversity. They are better options for building the scientific research. In addition, many botanic gardens are involved basis of in situ conservation of agrobiodiversity on-farm in the conservation of plants of importance for food and (Deribe et al., 2002). For instance, the farmers’ agriculture, as well as those used for many other indigenous knowledge and practices in germplasm economic purposes. selection, storage and exchange are major elements in Botanic gardens worldwide maintain approximately the conservation of agricultural biodiversity through 80,000 species as living plants (nearly 30% of the known community genebanks. vascular plant species of the world) represented by more The expansion of large-scale/modern agricultural than 4 million living accessions (individual plant systems, in which relatively a few improved varieties collections), and keep 250,000 seedbank accessions have replaced many farmers’ varieties, has caused (Hawksworth, 1995; Wyse Jackson, 1999). Many botanic erosion of agricultural biodiversity. Therefore, there is a gardens around the world have developed effective need for basing the rural development strategy on seedbanks for conserving germplasm of wild plant traditional farming systems, knowledge and agro- species. Perhaps the most important one to date is the ecological techniques in order to ensure the maintenance Millennium Seed Bank (MSB) at the Royal Botanic and continual use of the diverse genetic resources Gardens, Kew, UK, a major investment for the long-term associated with traditional agricultural systems (Miller et future of plant diversity (Smith et al., 2007). The two al., 1995). Farmer-based on-farm conservation of agro- principal aims of the project are to: i) collect and conserve biodiversity has been found a more successful approach. the world’s wild seed-bearing flora; and ii) develop bilateral research, training and capacity-building relationships worldwide in order to support and advance Ex situ conservation the seed conservation effort. The emphasis is on threatened and endemic species. A reserve of If in situ conservation is not feasible due to various germplasm of wild plants will be vital for reintroduction of reasons, threatened species can only be conserved ex threatened species and restoration of ecosystems. situ (Jeffries, 1997; Wolf, 1999). Moreover, ex situ Germplasm banks will also be a source of plants and conservation serves as a source of material for research genetic diversity for the development of new crops and and ecosystem restoration. However, ex situ conser- for the adaptation of old ones, for medicinal plants, and vation interrupts evolutionary and ecological processes other uses. If, as currently predicted, large numbers of and limits genetic variability and adaptability of species to species do become extinct in the wild, then the world’s changing environmental conditions. Furthermore, the seedbanks will become the only source to human kind of costs, risks and research needs of ex situ conservation those species and their germplasm in the future are significantly higher than that of in situ conservation. (Bramwell, 2007). Ex situ conservation methods include botanic gardens Botanic gardens, in cooperation with other bodies, are and arboreta, zoos, field genebanks and genebanks. increasingly involved in the in situ conservation of plant resources (Hawksworth, 1995; Heywood, 1999; Wyse Jackson and Sutherland, 2000; Bramwell, 2007). They Botanic gardens are involved in habitat management and restoration, plant reintroduction, control of invasive species and environ- Botanic gardens are institutions holding documented mental education. For instance, the Central Siberian collections of living plants for the purposes of scientific Botanical Garden, Novosibirsk, Russia is working with the research, conservation, display and education (Wyse managers of strictly protected scientific reserves to assist Jackson, 1999). Botanic gardens have played a vital role in management and restoration of rare and endangered in the conservation of the world’s plant diversity. Many of species for their own region. The Gladstone Tondoon the world’s threatened plant species are represented in Botanic Gardens, Queensland, Australia are collaborating their living collections or seedbanks which collectively with the Queensland National Park and Wildlife Service provide an insurance policy supporting the maintenance to manage and restore degraded areas of the forest. The of global biodiversity (Waylen, 2006). In fact, botanic Aburi Botanical Garden, Aburi, Ghana is involved in gardens have a strong focus on wild species which are complementary activities, such as promotion of some endangered in their natural habitat (Heywood, 1999; traditional medicinal plant management systems, Wyse Jackson, 1998). In more recent years, some management of protected areas and habitat restoration. botanic gardens started to accept new responsibilities Botanic gardens worldwide are also ideally placed to and were designed to be broadly based botanical raise awareness on the values of and threats to forests. resource centres (Wyse Jackson, 1998). They have been Over 400 botanic gardens worldwide manage areas of and still are ideal institutions for managing wild species natural vegetation or have natural areas within their

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boundaries (Wyse Jackson and Sutherland, 2000). For species in question. It needs area of sufficient size and example, the Rio de Janeiro Botanical Garden, Brazil has site conditions similar to that of the original population but an in situ conservation area of forest which is contiguous with a lower environmental load or pressure (Wolf, 1999). with the National Park of Tijuca in the Atlantic Rainforest – one of the world’s biodiversity hotspots (Guedes-Bruni and Pereira, 2008). All the National Botanical Gardens Genebanks (NBGs) in South Africa conserve an area of natural vegetation (Willis and Morkel, 2008). Botanic gardens Genebanks are important for the conservation of can be directed towards promoting integrated biodiversity germplasm or genetic material. Germplasms that can be conservation, combining and utilizing ex situ and in situ stored in genebanks include seeds, pollen, spores, techniques (Wyse Jackson and Sutherland, 2000). semen (sperms), eggs, embryos, cells and tissues. More Therefore, ex situ and in situ conservation are merging in recently, DNA sequences are also being kept in the world’s botanic gardens. specialized banks (Smith et al., 2007). In any case, Botanic gardens are living laboratories. They undertake representative sampling is necessary. Approximately 6 and promote scientific research on plants in particular million accessions of plants are maintained in genebanks and biological diversity in general. The research areas worldwide (Engels and Engelmann, 2002; Frison et al., include botany, taxonomy/systematics, ecology, horti- 2002). Germplasm conserved in genebanks serves for culture, plant breeding, evolutionary biology, conservation research and restoration purposes. biology, population genetics, molecular biology, In vitro conservation methods (storage of germplasm in biotechnology, invasive species biology and control, laboratory conditions) such as tissue culture storage climate change and environmental education. Many (micropropagation, that is, in slow growth condition) and botanic gardens maintain extensive collections and cryopreservation (storage of germplasm in dormant state) undertake research on useful plants of actual or potential are important for preservation of germplasm. value for agriculture, healthcare, horticulture, forestry, Cryopreservation of biological material using liquid habitat management and restoration, amenity and many nitrogen (-196°C) has a good potential for long-term other purposes. However, most botanic gardens do not storage of germplasm (Santos and Stushnoff, 2002). have sufficient human, financial and physical resources Increasingly, the difficult-to-conserve species are being to be able to achieve much effective conservation and maintained as in vitro collections. research into biodiversity. Therefore, there is a need to Based on their storage behaviour, seeds are provide the necessary resources so that botanic gardens categorized into three groups – orthodox, intermediate play important roles in the assessment and conservation and recalcitrant. Orthodox seeds are seeds which can of biodiversity. withstand conventional storage conditions (5% moisture content and -20°C) without viability loss, while recalcitrant seeds are seeds which cannot be stored below 20% Zoos moisture content and 0°C (Balcha, 1999; Allem, 2002; Santos and Stushnoff, 2002). Generally, recalcitrant Zoos have become increasingly important in the seeds do not show dormancy because they are in conservation of threatened wildlife. They are also continuous growth, that is, there is no resting period. important for educational and recreational purposes. Seeds are generally used for long-term storage of plant However, zoos generally are poorly developed and lack germplasm provided they are orthodox seeds (about 90% adequate funding. Therefore, there is a need for of plant species). Storage of orthodox seeds is not a high providing adequate human, financial and physical technology procedure. Seeds need to be dried down to 5- resources so that zoos can play an important role in the 7% moisture content and then stored in a cold room, conservation of threatened wild animals. usually at 4°C for short-term storage or -20°C for long- term storage (Smith et al., 2007). The drying stage is particularly critical because if a seed is not dry when Field genebanks frozen, it will be killed. Many countries lack the resources and technologies to Field genebanks are important for conservation of plant maintain germplasm in genebanks. Therefore, there is a species that do not produce seeds and propagate need for regional and international collaboration for vegetatively or produce the so-called recalcitrant seeds sharing of human, financial and physical resources and (seeds which cannot be stored at low temperature). technology development. The key areas where Usually these difficult-to-conserve species can be collaboration in germplasm management should be maintained as living collections in field genebanks. On encouraged are: germplasm collection, documentation, the other hand, conservation in field genebanks requires conservation, characterization, evaluation and rege- sound information on the ecological requirements of the neration; exchange of germplasm and information;

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identification of core collections (representative samples need to work closely for conserving biodiversity and of accessions); and research and training. improving human wellbeing.

CONCLUSION AND RECOMMENDATIONS ACKNOWLEDGEMENTS

Biodiversity includes a number of different levels of I would like to thank the National Herbarium (ETH) of the variation in the natural world. It can be measured at Addis Ababa University, Ethiopian Biodiversity Institute various levels. The most commonly used measures of (EBI), Ethiopian Institute of Agricultural Research (EIAR) biological diversity are genetic diversity, species diversity and the National Archives and Library Agency (NALA) of and ecosystem diversity. At spatial scales, biodiversity the Ministry of Culture and Tourism (MoCT) for allowing can be measured as alpha diversity, beta diversity, me to use their library. I also thank my relatives, friends gamma diversity and delta diversity. Biodiversity also and colleagues for their help and encouragement during includes cultural diversity (biocultural diversity). Bio- the writeup of the review. 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