Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: Who first defined ecosystems?
The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley.[fn 1][7] Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment.[8] He later refined the term, describing it as "The whole system, ... including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment".[9] Tansley regarded ecosystems not simply as natural units, but as "mental isolates".[9] Tansley later defined the spatial extent of ecosystems using the term ecotope.[10]
Ecosystem-based adaptation or EbA is an emerging strategy for community development and environmental management that seeks to use an ecosystem services framework to help communities adapt to the effects of climate change. The Convention on Biological Diversity currently defines Ecosystem-Based Adaptation as "the use of biodiversity and ecosystem services to help people adapt to the adverse effects of climate change", which includes the use of "sustainable management, conservation and restoration of ecosystems, as part of an overall adaptation strategy that takes into account the multiple social, economic and cultural co-benefits for local communities".
There are many reasons to restore ecosystems. Some include:There exist considerable differences of opinion in how to set restoration goals and how to define their success among conservation groups. Some urge active restoration (e.g. eradicating invasive animals to allow the native ones to survive) and others who believe that protected areas should have the bare minimum of human interference, such as rewilding. Ecosystem restoration has generated controversy. Skeptics doubt that the benefits justify the economic investment or who point to failed restoration projects and question the feasibility of restoration altogether. It can be difficult to set restoration goals, in part because, as Anthony Bradshaw claims, "ecosystems are not static, but in a state of dynamic equilibrium…. [with restoration] we aim [for a] moving target."
Defining clear and concise goals for ecosystem-based management is one of the most important steps in effective ecosystem-based management implementation. Goals must move beyond science-based or science-defined objectives to include social, cultural, economic and environmental importance. Of equal importance is to make sure that the community and stake-holders are involved throughout the entire process. Slocombe (1998a) also stated that a single, end-all goal cannot be the solution, but instead a combination of goals and their relationships with each other should be the focus.
Ascendency is a quantitative attribute of an ecosystem, defined as a function of the ecosystem's trophic network. Ascendency is derived using mathematical tools from information theory. It is intended to capture in a single index the ability of an ecosystem to prevail against disturbance by virtue of its combined organization and size.
Ecosystem services are defined as the gains acquired by humankind from surroundings ecosystems. Four different types of ecosystem services have been distinguished by the scientific body: regulating services, provisioning services, cultural services and supporting services. An ecosystem does not necessarily offer all four types of services simultaneously; but given the intricate nature of any ecosystem, it is usually assumed that humans benefit from a combination of these services. The services offered by diverse types of ecosystems (forests, seas, coral reefs, mangroves, etc.) differ in nature and in consequence. In fact, some services directly affect the livelihood of neighboring human populations (such as fresh water, food or aesthetic value, etc.) while other services affect general environmental conditions by which humans are indirectly impacted (such as climate change, erosion regulation or natural hazard regulation, etc.).
The concept of ecosystem collapse is used in the IUCN Red List of Ecosystems to establish categories of risk for ecosystems. The category "Collapsed" is used as the end-point of risk assessment. Other categories of threat (Vulnerable, Endangered and Critically Endangered) are defined in terms of the probability or risk of collapse.
Due to the high variety of ecosystems and their individual fluctuation in dependency on groundwater there is some uncertainty when it comes to defining an ecosystem strictly as groundwater-dependent or merely groundwater-using. Each ecosystem expresses a varying degree of dependency. An ecosystem can be directly or indirectly dependent, as well as have a variation in groundwater use throughout the seasons. There are a variety of methods for classifying types of groundwater-dependent ecosystems either by their geomorphological setting and/or by their respective groundwater flow mechanism (deep or shallow).
In the context of software analysis, the term software ecosystem is defined by Lungu as “a collection of software projects, which are developed and co-evolve in the same environment”. The environment can be organizational (a company), social (an open-source community), or technical (the Ruby ecosystem). The ecosystem metaphor is used in order to denote an analysis which takes into account multiple software systems. The most frequent of such analyses is static analysis of the source code of the component systems of the ecosystem.
Shugart (1997) was one of the first authors that used the term EFT as “aggregated components of ecosystems whose interactions with one another and with the environment produce differences in patterns of ecosystem structure and dynamics”. Walker (1997) proposed the use of a similar term, vegetation functional types, for groups of PFTs in sets that constitute the different states of vegetation succession in non-equilibrium ecosystems. The same term was applied by Scholes et al. (1997) in a wider sense for those areas having similar ecological attributes, such as PFTs composition, structure, phenology, biomass or productivity. Several studies have applied hierarchy and patch dynamic theories for the definition of ecosystem and landscape functional types at different spatial scales, by scaling-up emergent structural and functional properties from patches to regions. Valentini et al. (1999) defined land functional units by focusing on patches of the land surface that are able to exchange mass and energy with the atmosphere and show a coordinated and specific response to environmental factors.
Kurt Jax presented an ecosystem assessment format that avoids imposing a preconceived notion of normality, that avoids the muddling of normative and descriptive, and that gives serious attention to ecosystem definition. (1) Societal purposes for the ecosystem are negotiated by stakeholders, (2) a functioning ecosystem is defined with emphasis on phenomena relevant to stakeholder goals, (3) benchmark reference conditions and permissible variation of the system are established, (4) measurement variables are chosen for use as indicators, and (5) the time scale and spatial scale of assessment are decided.
In contrast to purely directive management efforts that attempt either to manage or direct outcomes, knowledge ecosystems espouse that knowledge strategies should focus more on enabling self-organization in response to changing environments. The suitability between knowledge and problems confronted defines the degree of "fitness" of a knowledge ecosystem. Articles discussing such ecological approaches typically incorporate elements of complex adaptive systems theory. Known implementation considerations of knowledge ecosystem include the Canadian Government.
Forest-Range Environmental Study Ecosystems, known as FRES, is a system for the classification of ecosystems developed by the United States Forest Service as a management tool for the entire lower 48. Thirty four ecosystems were defined for grasslands, forests and woodlands.
II. People
Startups and startup ecosystems are defined by the kind of people who form the startups or the ecosystem. In Hyderabad, with government support and infrastructural elements in place, it is now up to the entrepreneurs to build and develop this ecosystem.
There are several key conditions that typically define a healthy ecosystem. The ecosystem:
The Millennium Ecosystem Assessment (MA) report 2005 defines "Ecosystem services" as benefits people obtain from ecosystems and distinguishes four categories of ecosystem services, where the so-called supporting services are regarded as the basis for the services of the other three categories.
There is no single definition of what constitutes an ecosystem.[29] German ecologist Ernst-Detlef Schulze and coauthors defined an ecosystem as an area which is "uniform regarding the biological turnover, and contains all the fluxes above and below the ground area under consideration." They explicitly reject Gene Likens' use of entire river catchments as "too wide a demarcation" to be a single ecosystem, given the level of heterogeneity within such an area.[30] Other authors have suggested that an ecosystem can encompass a much larger area, even the whole planet.[31] Schulze and coauthors also rejected the idea that a single rotting log could be studied as an ecosystem because the size of the flows between the log and its surroundings are too large, relative to the proportion cycles within the log.[30] Philosopher of science Mark Sagoff considers the failure to define "the kind of object it studies" to be an obstacle to the development of theory in ecosystem ecology.[29]
(1) Patch characteristics: The characteristics of a freshwater ecosystem include its physical morphometry, chemical, and biological features, as well as its boundaries. These boundaries are often more easily defined for aquatic ecosystems than for terrestrial ecosystems (e.g., shoreline, riparian zones, and emergent vegetation zone) and are often a focal-point for important ecosystem processes linking terrestrial and aquatic components.
The relationship between systems ecology and ecosystem ecology is complex. Much of systems ecology can be considered a subset of ecosystem ecology. Ecosystem ecology also utilizes methods that have little to do with the holistic approach of systems ecology. However, systems ecology more actively considers external influences such as economics that usually fall outside the bounds of ecosystem ecology. Whereas ecosystem ecology can be defined as the scientific study of ecosystems, systems ecology is more of a particular approach to the study of ecological systems and phenomena that interact with these systems.
Ecosystem Functional Type (EFT) (Fig.1) is a new ecological concept to characterize ecosystem functioning. Ecosystem Functional Types are defined as groups of ecosystems or patches of the land surface that share similar dynamics of matter and energy exchanges between the biota and the physical environment. The EFT concept is analogous to the Plant Functional Types (PFTs) concept, but defined at a higher level of the biological organization. As plant species can be grouped according to common functional characteristics, ecosystems can be grouped according to their common functional behavior.
Certainly, 'landscape' is a central concept in landscape ecology. It is, however, defined in quite different ways. For example: Carl Troll conceives of landscape not as a mental construct but as an objectively given 'organic entity', a "harmonic individuum of space". 
Ernst Neef defines landscapes as sections within the uninterrupted earth-wide interconnection of geofactors which are defined as such on the basis of their uniformity in terms of a specific land use, and are thus defined in an anthropocentric and relativistic way.
According to Richard Forman and Michael Godron, a landscape is a heterogeneous land area composed of a cluster of interacting ecosystems that is repeated in similar form throughout, whereby they list woods, meadows, marshes and villages as examples of a landscape's ecosystems, and state that a landscape is an area at least a few kilometres wide. 
John A. Wiens opposes the traditional view expounded by Carl Troll, Isaak S. Zonneveld, Zev Naveh, Richard T. T. Forman/Michel Godron and others that landscapes are arenas in which humans interact with their environments on a kilometre-wide scale; instead, he defines 'landscape'—regardless of scale—as "the template on which spatial patterns influence ecological processes".
Some define 'landscape' as an area containing two or more ecosystems in close proximity.
There is discussion as to how the concept of cultural ecosystem services can be operationalized. A good review of approaches in landscape aesthetics, cultural heritage, outdoor recreation, and spiritual significance to define and assess cultural values of our environment so that they fit into the ecosystem services approach is given by Daniel et al. who vote for models that explicitly link ecological structures and functions with cultural values and benefits.
There also is a fundamental "critique" of the concept of cultural ecosystem services that builds on three arguments:The following examples illustrate the relationships between humans and natural ecosystems through the services derived from them:
By 2010, there had evolved various working definitions and descriptions of ecosystem services in the literature. To prevent double counting in ecosystem services audits, for instance, The Economics of Ecosystems and Biodiversity (TEEB) replaced "Supporting Services" in the MA with "Habitat Services" and "ecosystem functions", defined as "a subset of the interactions between ecosystem structure and processes that underpin the capacity of an ecosystem to provide goods and services".
The theoretical ecologist Robert Ulanowicz has used information theory tools to describe the structure of ecosystems, emphasizing mutual information (correlations) in studied systems. Drawing on this methodology and prior observations of complex ecosystems, Ulanowicz depicts approaches to determining the stress levels on ecosystems and predicting system reactions to defined types of alteration in their settings (such as increased or reduced energy flow, and eutrophication.
The issue of what exactly defines a vacant niche, also known as empty niche, and whether they exist in ecosystems is controversial. The subject is intimately tied into a much broader debate on whether ecosystems can reach equilibrium, where they could theoretically become maximally saturated with species. Given that saturation is a measure of the number of species per resource axis per ecosystem, the question becomes: is it useful to define unused resource clusters as niche 'vacancies'?