Journal of Earth Science & Climatic Change
Open Access

Ecosystems, in general, contribute a lot more to a lot more individuals than just pristine intrinsic values. They supply us with natural products, food, water, pest and disease control, and soil conservation, among other things (Millennium Ecosystem Assessment, 2005) [1]. On a regional or global scale, they have the potential to have significant impacts on climate and hydrology, as well as serve as important carbon sinks (The REDD desk, 2015). Ecosystems, on the other hand, are under great stress; tropical deforestation, for example, is occurring at an unprecedented rate in history, resulting in a reduction in both biodiversity and ecosystem services, with serious ramifications for civilization [2,3]. The majority of global governments acknowledged at the inaugural Earth Summit in 1992 that human actions were degrading the earth's ecosystems, eradicating species, biological features, and DNA at an alarming rate [4]. Species extinction is not rare in Earth's history; species appear and go at a regular rate (Center for Biological Diversity, 2015). However, complete habitat turnover for the benefit of one species (i.e., humans) is unusual and is currently occurring at worrying rates [5].

Biodiversity loss and deteriorating ecosystem services contribute –directly or indirectly-to worsening health, higher food insecurity, increasing vulnerability, lower material wealth, worsening social relations, and less freedom for choice and action,” according to the Millennium Ecosystem Assessment (2005) findings. Their result is unequivocal: biodiversity loss has a negative impact on human wellbeing. Despite the fact that ecosystem functioning, species richness, species composition, functional group richness, and genetic diversity appear to influence humanity's well-being, we have increased species extinction rates by 1,000 to 10,000 times the normal rates that occurred during Earth's history over the past centuries [6,7]. For birds, mammals, amphibians, and reptiles, current extinction rates are larger than or equal to those that would have occurred during any of the five previous big extinction events [8,9]. Because the drivers of biodiversity loss are either constant, show no signs of reducing in the future, or are even growing in intensity, 30 to 50 percent of all species may be on the verge of extinction by mid-century (Thomas et al.,). People have understood that ecosystem services, biodiversity, and our well-being are all intertwined, hence the recent and past loss of biodiversity is causing concern. This link exists because loss of biodiversity can lead to a reduction or loss of ecosystem services, which can lead to a fall in our well-being (Millennium Ecosystem Assessment, 2005). Over the last few decades, scientists have gained a better understanding of the link between biodiversity and ecosystem services, and people are increasingly appreciating the significance and value of this link (WWF, 2007). “With rising losses of unique species, humanity, far from hedging its risks, is getting progressively closer to the day when we will run out of options on a more unstable planet,” according to Sekercioglu (2010) [10]. As a result, if humanity is to continue surviving and increasing on a planet that essentially provides for all of our basic needs, we must be able to conserve our ecosystems while also learning more about the relationship between biodiversity and ecosystem services.

According to Mace et al. (2012), biodiversity is essential for the generation of ecosystem services; biodiversity can serve as an ecosystem service in and of itself, as a regulator of fundamental ecosystem processes, or as a good. For example, wild crop relatives' genetic diversity can be important for crop strain improvement (biodiversity as a service), diverse biological communities have increased pest resistance (biodiversity as a regulator), and biodiversity has recreational, religious, and educational value (biodiversity as a good) [11]. Ecosystem services can be influenced by biodiversity in both direct and indirect ways. The majority of humanity's food and fibers come directly from plants and animals, but biodiversity has an indirect impact on regulating services (such as seed dispersal and pollination) due to the way energy and materials are exchanged in ecosystems. Hence, changes in biodiversity loss can have a direct impact on an ecosystem's ability to generate and supply important services, and thus on economic, ecological, and social systems' long-term ability to adapt and respond to global influences.

To explain this relationship, the terms biodiversity and ecosystem services will be discussed first, followed by the link between the two. Nutrient cycling, oxygen production, carbon sequestration, water and air purification, and the creation of food, materials, and energy are just a few of these ecosystem services (Millennium Ecosystem Assessment, 2005).Finally, the main aim of this review was compiling the link between biodiversity, and ecosystem function and services.

Defining Biodiversity

The Convention on Biological Diversity (2015) defines biological diversity as "the variability among living organisms from all sources, including, inter alia, terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and among ecosystems; this includes diversity within species, between species, and among ecosystems." Biodiversity, as defined by Gaston & Spicer (2004), is “the diversity of life in all its numerous expressions, a wide unifying notion covering all forms, levels, and combinations of natural variation, at all levels of biological organization. From E. coli bacteria under your shoes to eyeless shrimps dwelling near hydrothermal vents (>400 °C) at 5000 meters depth in the Caribbean Sea, biodiversity is fundamentally cosmopolitan (Maxwell & Gerba, Connelly et al.,) Some habitats, on the other hand, have more species (i.e. are more species rich). Coral reefs, tropical rainforests, deciduous woods, vast tropical lakes, and the deep oceans are among the most speciesrich ecosystems [12].

The most biologically varied ecosystems on the planet include tropical rain forests and coral reefs, according to the Millennium Ecosystem Assessment (Millennium Ecosystem Assessment, 2005), while little is known about a number of ecosystems, such as deep marine habitats. The world's tropical rainforests, for example, cover only 7% of the planet's geographical area yet are home to more than half of the world's species (Corlett & Primack). These statistics, however, are based on the current number of described species, which is over 1.5 million, with insects being one of the most characterized taxonomic groupings. However, it is believed that 3 to 5 million species remain undescribed (Figure 1), and roughly 20,000 new species are described each year, with the majority of these still being insects or other arthropods (Gaston & Spicer, 2004). Today’s biodiversity is made up of currently identified taxa, yet biodiversity evolves over time, and the biological diversity we see today is neither what it was previously nor what it will be in the future. Approximately four billion species have evolved on Earth during the last 3.5 billion years, since the estimated origin of sustained, self-producing life [13]. Over 99 percent of these four billion species are now extinct [14]. Although these figures appear large, according to IUCN standards, between 10% and 50% of the world's species are currently endangered with extinction (Millennium Ecosystem Assessment, 2005).

Figure 1: Per category, the number of recognized species and an estimate of the number of undescribed species (Primack, 2010).

Furthermore, because the majority of species on the planet have yet to be properly described, documented numbers are likely to be grossly underestimated [15]. Species extinction rates have surged 1,000 to 10,000 times faster in the last few decades than they were in the past [6]. This shows that we are on the verge of a sixth mass extinction event, which might be triggered by human actions such as global climate change, habitat fragmentation, the introduction of non-native species, and pathogen expansion [16]. Due to the fact that the evolution of new species can take hundreds of thousands of years and the recovery from major extinction events can take millions of years [17,18], this poses a serious danger to ecosystem functioning. Nonetheless, the drivers of biodiversity loss and changes in ecosystem services are either constant, show no signs of diminishing in the future, or are intensifying (Millennium Ecosystem Assessment, 2005). According to Barnosky et al., [9], “if existing dangers to many species are not mitigated, the globe could achieve dramatic diversity loss that marked the five major extinctions within just a few centuries.” The loss of species diversity should be cause for concern, not only because of the loss itself, but also because of the impact on ecosystem services and ecosystem functioning, which will be examined further in the next chapters.

Components of Biodiversity

Several studies have shown that ecosystems are highly dependent on a variety of biodiversity components, which will be discussed in further depth in the following chapters. Species richness, species composition, and functional group richness are some of these components, and ecosystems can also be influenced by genetic diversity and species evenness [7]. Species composition is the relative abundance of each species in an ecological community, whereas species richness is the number of different species in an ecological community. The number of groups of species with similar functional trait qualities is called functional group richness, genetic diversity is called diversity within species, and species evenness is a measure of the relative abundance of the different species that make up the richness. Functional diversity, defined as the kind, relative abundance, and range of functional features present in a community, appears to be a key component in preserving ecological integrity and, as a result, providing ecosystem services [19,20]. Functional diversity affects and is affected by major drivers of global change, such as changes in land use, atmospheric composition, climate, and biotic interactions [2]. Several recent studies have demonstrated the relevance of functional diversity as the primary supplier of ecosystem services [2,21,22]. As functional diversity declines, the ecosystem becomes more susceptible, and tiny external events become more likely to cause alterations. This could lead to simpler ecosystems that are more vulnerable to perturbations in their ability to develop service-providing functions” (Martn-López et al.,).

In addition to the link between biodiversity and ecosystem services, ecological stability (a natural system's ability to return to a steady state after a disturbance) is also highly connected. For example, the effects of biodiversity loss on ecological processes could be as significant as the effects of many other global sources of environmental change. The effects of species loss on primary productivity are similar to those of ozone, UV radiation, fire, global warming, drought, herbivory, acidification, high CO₂, and nutrient pollution, according to recent research by Tilman et al., and Hooper et al. As a result, a decline in biodiversity and ecosystem functioning will almost certainly result in a reduction in ecological service provision. Ecosystems maintain a natural, steady state of functioning, and they have the ability to recover when they are disturbed or perturbed. However, an unbalanced ecosystem that is unable to operate correctly, for example owing to a loss of diversity, will not be able to recover, let alone provide any services useful to humans (Constanza et al.,).

To summarize, biodiversity has changed over time and will continue to do so; nevertheless, the rate at which it is changing currently is unparalleled in Earth's history and is a result of human activity. Our health, monetary prosperity, food security, vulnerability, social interactions, and freedom of choice and action all suffer as a result of the loss of biodiversity, ecosystem functions, and services (Millennium Ecosystem Assessment, 2005). The value of biodiversity, as well as the accompanying ecosystem functions and services, is critical to humanity's survival and should be our primary conservation goal. The term biodiversity will be used throughout this review to refer to all types of life on Earth.

Ecosystem functions and services

Over one billion people living in extreme poverty rely on ecosystem services (World Bank, 2006). Furthermore, 80 percent of the world's population relies on natural-source medicines (Ecological Society of America, 2006), and crop pollination by bees is responsible for 15-30 percent of the United States' food output [23]. Ecosystem functions supply us with valuable services and goods, and these services and goods are necessary for our survival [24]. According to Daily, ecosystem functions are "the capacity of natural processes and components to provide goods and services that directly or indirectly satisfy human needs," and ecosystem services are "the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life" (1997).

Many of these functions and services are not just useful but also necessary for our survival (air purification, temperature regulation, crop pollination), while others may only serve to improve it (aesthetics). Ecosystem services, according to Kremen (2005) are "the set of ecosystem functions that are helpful to humans." As a result of this definition, it is evident that if ecosystems do not function properly, we will have fewer, if not no, ecosystem services. The dominance of humans over the biosphere has resulted in major changes in ecosystem structure, composition, and function [25]. These alterations may have such a significant impact on ecosystem function that their ability to function correctly and offer services has already been harmed [26]. Over 60% of ecosystem services are deteriorating or already overused, according to the Millennium Ecosystem Assessment (2005). Although people have long recognized that natural ecosystems support human cultures, ecosystem services have only recently been recognized explicitly (Mooney & Ehrlich).

Regulation, habitat, production, and information functions are the four general kinds of ecosystem functions [24], which will be discussed more below. Regulation functions refer to ecosystems' ability to control life support systems and ecological processes via biogeochemical cycles and other biospheric processes including nutrient cycling and climate regulation. These functions support various services that benefit humans, including as clean water, soil, and air, and biological control services, in addition to preserving ecosystem health. Through the provision of reproduction habitat and refuge for flora and wildlife, habitat functions contribute to evolutionary processes and the maintenance of genetic and biological variety. Autotrophs convert water, energy, nutrients, and carbon dioxide into a variety of carbohydrate structures, which are then utilized by secondary producers to form a wider range of living biomass. Food, energy resources, raw materials, and genetic materials are among the numerous goods that this variety provides for humanity. The information functions that contribute to human health by giving possibilities for spiritual enrichment, reflection, recreation, aesthetic experience, and cognitive development are known as information functions [24].

These ecosystem functions are essential for ecosystems to function properly and deliver services to humans. Provisioning, regulatory, cultural, and supporting services are the four categories of ecosystem services that are delivered to humankind. Provisioning services supply us with actual ecosystem items like fuel, food, fibers, and fresh water. The benefits from the regulation of ecological processes that have a more indirect impact, such as climate regulation, water regulation, erosion control, and air quality maintenance, are known as regulating services. The non-material advantages acquired from ecosystems through recreation, spiritual enrichment, and aesthetic experiences are known as cultural services. Supporting services help mankind indirectly or over time, and are part of the complex structures and processes that provide other benefits. Nutrient cycling and soil formation are examples of supporting services [27].

Regulation functions

Natural ecosystems are essential for the proper functioning of life support systems and ecological processes. “The survival of the earth's biosphere as humanity's only life support system in an otherwise hostile cosmic environment is contingent on a careful balance between various ecological processes” [24]. The storage and transfer of energy and minerals in food chains, the mineralization of organic matter in sediments and soils, the translation of energy into biomass, biogeochemical cycles, and the regulation of the physical climate system are just a few examples of these processes. Regulation functions are critical to human survival on Earth, but they're generally only discovered after they've been badly disrupted or gone. We must protect the integrity and existence of natural ecosystems and processes in order for humanity to continue to benefit from these functions [28].

Habitat functions

All plants and fauna have a place to live in the earth's ecosystems. Because most of the world's ecosystem functions are provided by the diversity of species and their roles in ecosystems (Batker et al.,) maintaining healthy habitats is essential for the provision of all ecosystem services and products. Nursery and refugium functions are the two sub-functions of habitat functions. Many ecosystems across the world provide nursery and breeding habitats for species that are both crucial for humanity's survival and profitable. Natural ecosystems are also necessary for the preservation of genetic and biological variety on the planet since they provide living space. These ecosystems can be thought of as a genetic library, and maintaining their viability necessitates the preservation of natural ecosystems (De Groot et al., 2002; Batker et al., 2005).

Production functions

Water, food, oxygen, medical and genetic resources, energy, and raw materials are just a few of the resources that the Earth supplies. Humans have discovered how to alter ecosystem productivity to give greater than natural quantities of resources (De Groot et al., 2002; Batker et al., 2005). These production functions can be further subdivided into the following categories:

Food and raw materials

Although most foods are now sourced from crops and animals, natural flora and fauna still provide a significant portion of the diet. Natural ecosystems provide an almost limitless supply of edible plants and animals, including fruits, vegetables, fungus, game, fish, and fowl. Wood, biochemicals, fibers, and organic matter are among the renewable resources they supply. Alcamo et al., 2003; Verweij et al., 2009; Haines-Young & Potschin, 2010) use these resources for construction, fuel, handicrafts, and apparel [27,28].

Genetic Resources

Without the genetic diversity of their wild relatives, humans would be unable to sustain many commercial crops. Regular inputs of genetic material from wild relatives are required to improve a crop's quality (e.g., size, taste, and disease resistance) or sustain its productivity [24].

Medicinal Resources

Chemicals found in nature can be employed as medications and therapies. Epibatidine, a chemical derived from the skin of the Phantasmal poison frog, is one example (Epipedobates tricolor). This chemical's derivative has the power to kill pain 200 times more effectively than morphine while avoiding the undesirable side effects [29]. Animals are also employed as medical equipment, student specimens, or to test novel medications [30].

Information functions

Natural ecosystems offer a wide range of recreational, educational, spiritual, and mental growth opportunities. Nature is a crucial source of inspiration for art, science, and culture, as well as a wealth of research and educational opportunities (Batker et al., 2005). Environmental environments provide a highly inspirational and instructional kind of recreative experience, with potential for spiritual enrichment, cognitive development, and contemplation through exposure to living processes and natural systems, as Forster (1973) stated 40 years ago.

Valuing ecosystem functions and services

Ecosystem valuation is a notion that can help us comprehend and quantify the value of the functions and services offered by nature. These roles and services must be valued in order to guide future human actions in a sustainable manner. The economic, ecological, and socio-cultural values of an ecosystem's functioning and services can be classified into three categories, as stated below.

Economic value: Direct market value, indirect market value, group value, and contingent value are all methods for determining the economic value of an ecosystem. The exchange value of an ecosystem service in commerce, namely production (e.g., food), regulation (e.g., water filtration), and information functions, is known as direct market value (e.g., recreation). When an ecosystem lacks explicit market values, indirect market values are used. Indirect valuation strategies include people's willingness to accept compensation and pay for the availability or loss of ecosystem services. Contingent valuation entails polling people to determine how much they are prepared to pay for specific ecosystem services, as well as how much compensation they are willing to take in exchange for those services. Social justice, fairness, and non-human values are among the value kinds captured by group valuation, which are not included in contingent valuation approaches [31,32]. Unfortunately, the value of ecosystem services is not completely reflected in commercial markets, and expressing their worth in monetary terms is challenging, thus they are frequently overlooked in key policy choices. As a result, Constanza et al., [33] calculated the value of 17 ecosystem services on a global scale. The computation only took into account renewable ecosystem services; non-renewable minerals and fuels, as well as the atmosphere, were left out. Ecosystems are expected to produce at least $33 trillion in annual services, and possibly as much as $54 trillion. In 1997, its annual value was about 1.8 times the worldwide Gross National Product. The value of ecosystem services is only likely to rise as these services become more stressed and scarcer [32].

Ecological value: The ecological value of an ecosystem's services and functions can be described as the capacity of an ecosystem to deliver these services and commodities based on the ecosystem processes and components that provide them. To ensure the continuous availability of ecosystem functions, the use of these services and goods should be limited to sustainable levels. If we continue to use services and things in an unsustainable way, the pressure on ecosystems will grow until they collapse. An ecosystem will be unable to fulfill its potential services at this time. Ecological guidelines establish the limits of sustainable use (e.g., resistance, resilience, and integrity). Ecosystem metrics such as diversity, rarity, and complexity, as well as the integrity of the regulation and habitat functions, are ecological measurements of ecosystem worth [1,24,32].

Socio-cultural value: Many people consider biodiversity and natural ecosystems to be important sources of non-material wellbeing because of their impact on people's national, historical, religious, ethical, and spiritual values. Environmental functions, education, physical and mental health, independence, and cultural diversity and identity are all influenced by social factors (English Nature, 1994). As a result, natural systems are critical for a sustainable civilization and a source of non-material wellbeing [24,32,34].

Links between biodiversity, ecosystems functions and services

The role of biodiversity in ecosystem delivery has been hotly discussed in recent years, and supporting and implementing the ecosystem services framework is one of the most important ways to improve the case for biodiversity protection (MEA 2005; TEEB 2011). The framework serves as a foundation for defining, tracking, and valuing ESs. It also contributes to raising awareness about the importance of biodiversity, natural habitats, and ecosystems conservation. Although some studies treated biodiversity as an ecosystem service itself (Egoh et al. 2010, 2009) [35], the general idea that biodiversity in a particular ecosystem sustains most of the services delivered by that ecosystem is accepted [4,7,36]. Although some studies treated biodiversity as an ecosystem service itself (Egoh et al. 2010, 2009), the general idea that biodiversity in a particular ecosystem sustains most of the services [7,37].

Ecosystem functioning, and the extent to which species contribute to that functioning, are required for the delivery of ecosystem services [37]. As a result, the concept of ecosystem function is extremely difficult to grasp. Currently, two widely debated mechanisms have been proposed to explain the role of biodiversity in ecosystem functioning: selection effects or sampling effects (Huston 1997) [38] and niche complementarity/facilitation effects [39]. The selection effect hypothesis assumes that in ecosystems with greater diversity, dominant species or traits are more likely to occur. According to the niche complementarity hypothesis, highly diverse ecosystems allow for a wider range of functional features and more effective resource utilization, resulting in increased ecosystem functions. Because it is difficult to discern between niche complementarity and facilitation in reality, both are commonly referred to as the "complementarity effect" (Loreau and Hector 2001) [40]. Forest biomass and productivity can rise as a result of a few highly productive and dominating species (Finegan et al. 2015), or as a result of improved performance of all species present through facilitation and higher resource use efficiency [41,42].

The ongoing decline in ecosystem service delivery [24,43-45] combined with the alarming rate of ecosystem degradation [30,46,47] has pushed the issue of the links between biodiversity and ecosystem function and services to the forefront of research agendas [23,48]. Understanding these interactions is critical not only for proving theoretical predictions (niche complementarity and selection impacts), but also for developing biodiversity and ecosystem service conservation strategies [36,48].

The importance of biodiversity in ecosystem functioning and service delivery has been extensively studied over the last two decades [4,49]. Cardinale et al. (2011) found that plant litter diversity improved breakdown and recycling of components after organism death in a metaanalysis. Stand productivity and/or biomass is another example, and by far the most prevalent of ecosystem functions in plant communities. In some previous research [39], stand biomass was utilized as a major productivity parameter; however, increment of biomass, basal area, or carbon could be more relevant metrics for aboveground biomass productivity [41,42]. Based on data from [50], an investigation of the connection between mean biomass and gross primary production revealed a positive correlation across diverse forest ecosystems (Figure 2), implying that biomass can be used as a proxy for productivity. Only 14 percent of the biodiversity-productivity connections detailed by [51] really examined productivity, while 34.4 percent of the studies employed biomass as a proxy [52]. Jenkins (2015), who typically cautioned against using biomass to forecast productivity carelessly, pointed out that log-log productivity-biomass data revealed models, implying a strong relationship between productivity and biomass. Most biodiversity and ecosystem function studies based on productivity or biomass have focused on natural and experimental grasslands systems (Feßel et al. 2016; Hector et al. 1999; Tilman et al. 1996), mixed temperate forest stands, and less diverse forest ecosystems [53,54], while less effort has gone into tropi (Paquette and Messier 2011; [55,56]. With a few exceptions [57] evidence is emerging that increasing biodiversity effects ecosystem functioning positively in grasslands (Adler et al. 2011; Feßel et al. 2016; mová et al. 2013). In contrast, there is minimal consensus among research that have looked at the relationship between biodiversity and production in natural forests [58].

Figure 2: Relationship between mean biomass and gross primary production across different forest ecosystems (Stiling, 1996).

If it is assumed that increasing plant diversity in forest ecosystems increases ecosystem functions, and that biodiversity loss has a negative impact on ecosystem functioning and services provided [4,37,59] it must be stated that current knowledge of the mechanisms 7is limited (Paquette and Messier) [36,60]. Ruiz-Jaen and Potvin (2011) found a negative relationship between species diversity and biomass production in natural forests of Barro Colorado Island in Central Panama, Szwagrzyk and Gazda (2007) [61] in natural forests of Central Europe, and An-ning et al. (2008) in natural forest communities in Northwest China. In other investigations, such connections were shown to be insignificant [62]. While the contradictory results, particularly in forest ecosystems, may suggest that the mechanisms that drive the biodiversity-ecosystem function relationship are environmentdependent, an important conclusion emerging from the available literature is that natural tropical forests are largely under-represented. This is true despite the fact that these forests can house hundreds of species with a variety of functional features, and studies from temperate mixed species or less diverse forest ecosystems may not apply.

It's also worth noting that, for years, richness (species richness) has been used to explain the relationship between biodiversity and ecological services as a basic metric of biodiversity. The current trend is to investigate how functional diversity, phylogenetic diversity, and functional dominance have a major role in ecosystem functioning [53,60, 63,64]. (Baraloto et al. 2012; Clark et al. 2012; Ouyang et al. 2016; Ruiz Jaen and Potvin 2011) [54,65,66] . The value and range of functional qualities of the organisms present in a particular ecosystem is known as functional diversity (Diaz and Cabido, 2001) [67], and it may be more significant to forecast the functional contribution of individual species in ecosystem level processes. Functional diversity can be used as a proxy to assess niche space and niche differentiation among species, as Mouchet et al. (2010) [68] point out, and so can be used to evaluate the niche complementarity hypothesis. Functional dominance (Figure 3) is a measure of how dominant a functional feature is over other qualities. It's widely used to examine dominance patterns and selection impact hypotheses [41,69]. Phylogenetic diversity, often known as a community's evolutionary history, has also been presented as a method for predicting ecological functions [70,71]. Understanding whether and how functional diversity, functional dominance, and/or phylogenetic diversity transmit the full impacts of diversity on ecosystem function will aid in determining which mechanism is the most important [72-80].

Figure 3: Relationship between ecosystem function and species richness for each functional group species (Wu et al. 2015).

Most ecological services are directly linked to biodiversity, but not always in a straightforward way. For most ecosystem services, the nature of the link between biodiversity and ecosystem service delivery is largely unknown. Relationships are highly variable and can be positive, negative, or non-linear for those that are known. The number, identity, functional qualities, and evenness of species all have a role in ecosystem functioning and, as a result, the supply of various services. We now have a better knowledge of these interconnections because to concepts and methodologies like ecosystem service providers and traitbased approaches, as well as a better understanding of the mechanisms by which variety affects ecosystem function. At numerous spatial scales, biodiversity is likely to influence the long-term sustainability of functional social-ecological systems and the flow of benefits from nature to societies. Multi-scale, multidisciplinary research in partnership with stakeholders is required to comprehend these longer and larger-scale dynamics. Long-term studies and assessments of numerous ecosystem services show that the extinction of a few species can have a negative impact on service availability and, as a result, human well-being.