Concept
Download our Ecosystem Services Pictorial presentation: “What are ecosystem services?”
Ecosystem Services can be subdivided into five categories: provisioning such as the production of food and water; regulating, such as the control of climate and disease; supporting, such as nutrient cycles and crop pollination; cultural, such as spiritual and recreational benefits; and preserving, which includes guarding against uncertainty through the maintenance of diversity.
BACKGROUND:
As human populations grow, so do the resource demands imposed on ecosystems and the impacts of our global footprint. Many people have been plagued with the misconception that these ecosystem services are free, invulnerable and infinitely available. However, the impacts of anthropogenic use and abuse are becoming evermore apparent – air and water quality are increasingly compromised, oceans are being over-fished, pests and diseases are extending beyond their historical boundaries, deforestation is eliminating flood control around human settlements. It has been reported that approximately 40-50% of Earth’s ice-free land surface has been heavily transformed or degraded by anthropogenic activities, 66% of marine fisheries are either overexploited or at their limit, atmospheric CO2 has increased more than 30% since the advent of industrialization, and nearly 25% of Earth’s bird species have gone extinct in the last two thousand years. Consequently, society is coming to realize that ecosystem services are not only threatened and limited, but that the pressure to evaluate trade-offs between immediate and long-term human needs is urgent. To help inform decision-makers, economic value is increasingly associated with many ecosystem services and often based on the cost of replacement with anthropogenically-driven alternatives. The on-going challenge of prescribing economic value to nature, such as through processes like biodiversity banking, is prompting transdisciplinary shifts in how we recognize and manage the environment, social responsibility, business opportunities, and our future as a species.
The simple notion of human dependence on Earth’s ecosystems probably reaches to the start of our species’ existence, when as hunter-gatherers we benefited from the products of nature to nourish our bodies and for shelter from harsh climates. Recognition of how ecosystems could provide more complex services to humankind date back to at least Plato (c. 400 BC) who understood that deforestation could lead to soil erosion and the drying of springs. However, modern ideas of ecosystem services probably began with Marsh in 1864 [3] when he challenged the idea that Earth’s natural resources are not infinite by pointing out changes in soil fertility in the Mediterranean. Unfortunately, his observations and cautions passed largely unnoticed at the time and it was not until the late 1940s that society’s attention was again brought to the matter. During this era, three key authors – Osborn, Vogt, and Leopold – awakened and promoted recognition of human dependence on the environment with the idea of ‘natural capital’. In 1956, Sears drew attention to the critical role of the ecosystem in processing wastes and recycling nutrients. An environmental science textbook called attention to “the most subtle and dangerous threat to man’s existence… the potential destruction, by man’s own activities, of those ecological systems upon which the very existence of the human species depends”. The term ‘environmental services’ was finally introduced in a report of the Study of Critical Environmental Problems, which listed services including insect pollination, fisheries, climate regulation and flood control. In following years, variations of the term were used, but eventually ‘ecosystem services’ became the standard in scientific literature.
ECOSYTEM SERVICES CATEGORIES:
Experts currently recognize five categories of ecosystem services.The following lists represent samples of each:
Provisioning services
- foods (including seafood and game) and spices
- precursors to pharmaceutical and industrial products
- energy (hydropower, biomass fuels)
Regulating services
- carbon sequestration and climate regulation
- waste decomposition and detoxification
- nutrient dispersal and cycling
Supporting services
- purification of water and air
- crop pollination and seed dispersal
- pest and disease control
Cultural services
- cultural, intellectual and spiritual inspiration
- recreational experiences (including ecotourism)
- scientific discovery
Preserving services
- genetic and species diversity for future use
- accounting for uncertainty
- protection of options
THE ROOT AND MEANING:
Understanding of ecosystem services requires a strong foundation in ecology, which describes the underlying principles and interactions of organisms and the environment. Since the scales at which these entities interact can vary from microbes to landscapes, milliseconds to millions of years, one of the greatest remaining challenges is the descriptive characterization of energy and material flow between them. For example, the area of a forest floor, the detritus upon it, the microorganisms in the soil and characteristics of the soil itself will all contribute to the abilities of that forest for providing ecosystem services like carbon sequestration, water purification, and erosion prevention to other areas within the watershed. Note that it is often possible for multiple services to be bundled together and when benefits of targeted objectives are secured, there may also be ancillary benefits – the same forest may provide habitat for other organisms as well as human recreation, which are also ecosystem services.
The complexity of Earth’s ecosystems poses a challenge for scientists as they try to understand how relationships are interwoven among organisms, processes and their surroundings. As it relates to human ecology, a suggested research agenda for the study of ecosystem services includes the following steps:
Identification of ecosystem service providers (ESPs) – species or populations that provide specific ecosystem services – and characterization of their functional roles and relationships;
Determination of community structure aspects that influence how ESPs function in their natural landscape, such as compensatory responses that stabilize function and non-random extinction sequences which can erode it;
Assessment of key environmental (abiotic) factors influencing the provision of services;
Measurement of the spatial and temporal scales ESPs and their services operate on.
Recently, a technique has been developed to improve and standardize the evaluation of ESP functionality by quantifying the relative importance of different species in terms of their efficiency and abundance. Such parameters provide indications of how species respond to changes in the environment (i.e. predators, resource availability, climate) and are useful for identifying species that are disproportionately important at providing ecosystem services. However, a critical drawback is that the technique does not account for the effects of interactions, which are often both complex and fundamental in maintaining an ecosystem and can involve species that are not readily detected as a priority. Even so, estimating the functional structure of an ecosystem and combining it with information about individual species traits can help us understand the resilience of an ecosystem amidst environmental change.
Many ecologists also believe that the provision of ecosystem services can be stabilized with biodiversity. Increasing biodiversity also benefits the variety of ecosystem services available to society. Understanding the relationship between biodiversity and an ecosystem’s stability is essential to the management of natural resources and their services.
The Redundancy Hypothesis: The concept of ecological redundancy is sometimes referred to as functional compensation and assumes that more than one species performs a given role within an ecosystem. More specifically, it is characterized by a particular species increasing its efficiency at providing a service when conditions are stressed in order to maintain aggregate stability in the ecosystem. However, such increased dependence on a compensating species places additional stress on the ecosystem and often enhances its susceptibility to subsequent disturbance. The redundancy hypothesis can be summarized as “species redundancy enhances ecosystem resilience”.
The Rivet Hypothesis: Another idea uses the analogy of rivets in an airplane wing to compare the exponential effect the loss of each species will have on the function of an ecosystem; this is sometimes referred to as rivet popping. If only one species disappears, the efficiency of the ecosystem as a whole is relatively small; however if several species are lost, the system essentially collapses as an airplane wing were it to lose too many rivets. The hypothesis assumes that species are relatively specialized in their roles and that their ability to compensate for one another is less than in the redundancy hypothesis. As a result, the loss of any species is critical to the performance of the ecosystem. The key difference is the rate at which the loss of species affects total ecosystem function.
The Portfolio Effect: A third explanation, known as the portfolio effect, compares biodiversity to stock holdings, where diversification minimizes the volatility of the investment, or in this case, the risk in stability of ecosystem services. This is related to the idea of response diversity where a suite of species will exhibit differential responses to a given environmental perturbation and therefore when considered together, they create a stabilizing function that preserves the integrity of a service.
Several experiments have tested these hypotheses in both the field and the lab. In ECOTRON, a laboratory in the UK where many of the biotic and abiotic factors of nature can be simulated, studies have focused on the effects of earthworms and symbiotic bacteria on plant roots. These laboratory experiments seem to favor the rivet hypothesis. However, a study on grasslands at Cedar Creek Reserve in Minnesota seems to support the redundancy hypothesis, as have many other field studies.
Management and policy
Although monetary pricing continues with respect to the valuation of ecosystem services, the challenges in policy implementation and management are enormous. The administration of common pool resources is a subject of extensive academic pursuit.[From defining the problems to finding solutions that can be applied in practical and sustainable ways, there is much to overcome. Considering options must balance present and future human needs, and decision-makers must frequently work from valid but incomplete information. Existing legal policies are often considered insufficient since they typically pertain to human health-based standards that are mismatched with necessary means to protect ecosystem health and services. To improve the information available, one suggestion has involved the implementation of an Ecosystem Services Framework , which integrates the biophysical and socio-economic dimensions of protecting the environment and is designed to guide institutions through multidisciplinary information and jargon, helping to direct strategic choices.
Novel and expedient methods are needed to deal with managing Earth’s ecosystem services. Local to regional collective management efforts might be considered appropriate for services like crop pollination or resources like water.[ Another approach that has become increasingly popular over the last decade is the marketing of ecosystem services protection. Payment and trading of services is an emerging world-wide small-scale solution where one can acquire credits for activities such as sponsoring the protection of carbon sequestration sources or the restoration of ecosystem service providers. In some cases, banks for handling such credits have been established and conservation companies have even gone public on stock exchanges, defining an evermore parallel link with economic endeavors and opportunities for tying into social perceptions.However, concerns for such global transactions include inconsistent compensation for services or resources sacrificed elsewhere and misconceived warrants for irresponsible use. Another approach has been focused on protecting ecosystem service ‘hotspots’. Recognition that the conservation of many ecosystem services aligns with more traditional conservation goals (i.e. biodiversity) has led to the suggested merging of objectives for maximizing their mutual success. This may be particularly strategic when employing networks that permit the flow of services across landscapes, and might also facilitate securing the financial means to protect services through a diversification of investors.
Definition: “To understand and value the critical functions natural systems provide to humankind, as a means to insuring a mutually sustainable future.”