Generally, the standard about ecosystems health is relative, it is difficult to judge whether the ecosystem is healthy. However, the comparison between the different ecosystem  quality in different temporal state would help judgging the improvement. 

A methodology may be useful for your concern:

Article A state-impact-state methodology for assessing environmental...

In general, ecosystem health can be thought of as a differential of biodiversity. If a particular ecosystem has a biodiversity index of x In the past, this can be a standard to which to compare the current status. Loss of biodiversity is a health reduction, but biodiversity increase isn't necessarily an improvement because some could be invasive species. So, local expertise is needed, especially when records are sparse. Typically they are key indicator species for many ecosystems, e.g., streams and rivers which have a high sensitivity to toxins or disturbance/perturbation. Interesting question.

Thomas McCloughlin that is a useful metric, and I may use it myself in future, but what about cases of apparent inherent low diversity such as hot (or cold) deserts, or perhaps cave systems? I know you said an increase is not necessarily a good thing, but as you indicated biodiversity is taken to be the metric to maximise, without introducing foreign species. It takes no account of abiotic processes, matter and energy cycles etc. Could there/is there any measure of ecosystem health which focuses on or includes these other important elements of the whole system? 

My philosophical reasoning for including such would be that, for example in the arctic, changes in temperature-days (either air or water) may reduce the ice pack or terrestrial glacier mass, changing the volume of matter flow through one species or set of species, e.g. polar bears, but potentially increasing it in others, such as seals (reduced predation possibly). New species coming in with the changing abiotic conditions may complicate the situation also, with locals becoming extinct at roughly the same rate as new introductions, resulting in an apparent steady-state in biodiversity terms.

the best way is to see older studies about your ecosystem...

Yes, Diarmuid, you are right, as much data should be included as possible and I was merely speaking very generally.  Some bioindicators can indicate for specific toxins and their numbers can correlate to toxin concentration but many are too general.  However, if looking at the historical condition of the habitat, one can find biotic records in many places in Europe going back to before 1900, whereas abiotic data is much more recent.  In the case of streams and rivers I always ask students to collect abiotic as well as biotic but I find that the more data sources I introduce, the more unreliable the students consistency in recording! Biotic data recording is also restricted by seasonal changes which relate to energy cycles (daylength, average temperature) or behavioural cycles (reproduction).  Typically, biologists from different fields use a different conceptual lens when examining ecosystems.  I am moving into looking at DNA in soil and water from ecosystems as this might indicate past species no longer present.

Dear Wilbert ,

From the fungal point of view, presence of more saprophytic and parasitic species than the symbiotic or mycorrhizal species indicates that the health of the ecosystem is deteriorating.

However, any point observation regarding ecosystem health is a minuscule part of 'natural cycle' and degradation and amelioration of ecosystem health is a continuous process.

Best wishes,

Prakash

I for myself differentiate between ecology and "nature conservation".

Ecology is the science of interaction between the influencing parameters in nature, and it makes no sense to call a situation "good" or "bad" or "healthy" or not. From a scientific point of view, it is how it is, we want to know why it is so and how it changes or not. Would it be stable or not is a  senseful criteria.

Nature conservation, on the other side, makes a judgement, what is good, what is bad, which situation would we like to stabilize or to establish. And even here there can be different philosophies leading to different results, for example in human influenced areas like  meadows, which exist only with artificial influences. 

So the answer to your question depends on the philosophy of nature, you are sticked to.

Best wishes

Rudi

Personally I would avoid using the term "ecosystem health".  It's one of those phrases that is used without any real thought as to what it means, and once you start pulling it apart means nothing at all.  Any ecosystem that supports its component species could be considered "healthy". but that would include ecosystems that appear very degraded from a human perspective, e.g. a highly eutrophic lake.  It's much better to think in terms of ecosystem functions, flows of energy and nutrients, presence of native species and their interactions, etc.  

Species richness is often considered as the measure of ecosystem health. As ecosystem is the interaction between and amongst its biotic and abiotic components. And its connected through food chains and food webs. This is the how energy is transferred from one trophic level to the other. Hence, species richness provides a stability to the ecosystem as the loss of one genus may not have a negative impact as their may be a replacement of that genus may be present or energy channel (food chain) follows a new path through any other species. 

I think one of the most effective ways to assess the "health" of an environment is study it comparatively to ecosystems of a certain region. Draw up a matrix with various metrics allows you to assign a note to biological integrity, creating a measurable index. Higher grades, greater "health" of the ecosystem

Dear Herzog, I do agree with your explanation. But, ecosystem stability correlates with species richness and that too with the ecosystem health. "Ecosystem health" is an ambiguous term. But in general term health means "the state of being free from illness or injury". So, the ecosystem with more of diversity have more stability. When you give a reference of an Arctic ecosystem with that of tropical rain forest, they stand opposite to each other in species richness, biomass production, stability, as one being the least and the other as the highest respectively. Arctic ecosystem is more prone to disturbances than that of Tropical ecosystem. So, biodiversity is common factor for measuring an "ecosystem health", but it may not be equatable to all the ecosystems. 

Aldo Leopold's concept of "land health" is helpful in this context.  In a 1944 essay he offered this:  "Conservation is a state of health in the land.  The land consists of soil, water, plants, and animals, but health is more than a sufficiency of these components. It is a state of vigorous self-renewal in each of them, and in all collectively. Such collective functioning of interdependent parts for the maintenance of the whole is characteristic of an organism. In this sense [emphasis added] land is an organism, and conservation deals with its functional integrity, or health."

These publications could be useful:

http://link.springer.com/article/10.1007%2FBF01873258#page-1

https://books.google.bg/books?id=kcncBwAAQBAJ&printsec=frontcover&hl=bg#v=onepage&q&f=false

I agree that "ecosystem health" is a very anthropocentric and fuzzy term, and as such I think that if you are going to use it then the human side of the equation needs to be considered. Many other responders have given good suggestions for use in systems where human interests are not involved or of primary concern, but I don't think these measures can be the only measures if we are talking system "health". As an anthropocentric concept, I think the most important question to ask when you want to evaluate "ecosystem health" is the question "Healthy for what?" Biodiversity preservation? Nursery system? Food production? Transportation? None or all of the above? That means there needs to be some indication of the goals for that ecosystem (ecological and human {to use a division of convenience}, and hopefully compatible) in order to give a reference against which to evaluate "health". Otherwise, I think the statement that a particular system is or is not healthy will have little practical or value-added meaning.

For example, by most ecological measures a location such as Baltimore (Maryland) Harbor is not particularly "healthy" in an ecological sense compared to other coastal areas without harbors, but that is exactly the point: those other locations are not major commercial ports. We probably would not expect a "healthy" port and a "healthy" saltmarsh reserve to be ecologically similar, nor would all our goals for those systems be the same. Or a spring run could be classified "unhealthy" for having a higher nitrogen load than other springs. But if that load is coming from the groundwater in aquifers flowing from urban areas far away from the manager's influence, the critical populations the manager oversees have been present in approrpiate numbers for years, and people are still able to use the spring run for recreation safely, of what significance to the manager is declaring the spring "unhealthy"?  Rather, for "health" measures we certainly could and should set ecological, social, etc. goals for those systems with an eye toward maintaining at least some minimal levels in all of them and then determine whether or not we are meeting those goals. As long as we don't sell out the ecological requirements to the others (a VERY important caveat), that would at least give us a meaningful target to shoot for, and would make a declaration of a system as being "unhealthy" a useful exercise. Otherwise, all we end up saying in the word "unhealthy" is that ecosystems are ecologically impacted by human activities, which we already know. The question is how far we are willing to go in exchange for what other benefits. While "ecosystem health" is an anthropocentric approach, given our increasing impacts on all kinds of ecosystems I think the approach will probably become more important as time goes on.

We need ecosystem-level reference points, analogous to the ones used in fisheries management or toxicology LD50s. 

There are many such thresholds under development; can provide a list if you like.

Mostly these are emergent, often integrative properties of the salient components of an ecosystem that are responding to some multivariate suite of pressures.

FYI, although understand the gestalt of the term and it is useful in broader communications, really ecosystem health is referring to ecosystem status against some a priori determination of threshold.

Dear Shreya,

species richness allone can not be a criteria. Moors are known to have less species richness. Are they not healthy? The species richness in mountains decrease with the height. How do you evaluate this?

Often it happens, that the species richness increases throughout invasive animals and plants, for example on islands like on Teneriffa. I think, this is good (for the invasive species!). It depends on point of view!

And you can go on: A lot of species richness once was originated by separating parts of a species or by invading new territories of a species. Is separating good or bad? Are invasive species good or bad? Is the extinction of the dinosaurs good or bad?

Best wishes

Rudi

Dear Wilbert,

This theme is very current and has been studied by several research groups, giving rise to scientific journals and various publications.

The health of ecosystems is closely linked to the survival of human beings on our planet, using the natural resources necessary for survival.

Sending down the link to an article on the subject.

http://www.esajournals.org/doi/pdf/10.1890/EHS14-0013.1

Good job,

Claudio de Moura

Agree on the fuzziness of the term. Recently, it gets even more crazy when it is used as a metaphor in the One Health/EcoHealth and What Health (!) concepts along with Human and Animal (domestic and wildlife) Health... It's catchy but people don't know what they are talking about and what they imply. My gut ecosystem is more or less healthy I would say... not sure if my bacteria agree (especially during christmas).

I tend to like this article:

https://www.pdx.edu/sites/www.pdx.edu.sustainability/files/Rapport%20et%20al.%201998.pdf

Different groups may define it differently. Māori researchers in New Zealand have worked on a Cultural Health Index approach, and the Māori language has a term for the life force of an area, "mauri", which can be in good condition or poor condition, and is judged by a number of factors including things like bird song. This pdf will give you a sense of it. Here's the definition of "mauri" given.

Mauri: the three components of the Cultural Health Index collectively represent a means by which Māori will measure the present health of the river in a holistic manner, thus enabling them to assess the extent to which contemporary resource management protects the mauri of the resource.

https://www.mfe.govt.nz/sites/default/files/cultural-health-index-for-streams-and-waterways-tech-report-apr06.pdf

Hi,

I am also not a big fan of the word "health" in this context, yet it is commonly used in ecology and described as the co-occurrence of all, or most, of the following ecosystem properties: 

1. Homeostasis

2. Absence of disease

3. Diversity or complexity

4. Stability or resilience

5. Vigor or scope for growth

6. Balance between system components

The issue of bioindication to assess ecosystem properties is quite relevant to your question, so I would recommend reading the following text:

Jørgensen et al. (2010). Handbook of Ecological Indicators for Assessment of

Ecosystem Health. CRC Press 

freely available at: 

http://190.11.224.74:8080/jspui/bitstream/123456789/1225/2/ebooksclub.org__Handbook_of_ecological_indicators_for_assessment_of_ecosystem_health.pdf

I hope this helps

Best

Danilo

I agree with Sven and Jeff. I don't like this and other new ecological? new , fashionable terms generally without a clear ecological meaning, but that are used and abused by journalists and politicians. And unfortunately by some researchers too.

When it supports a diversity of species.

I agree with Sven, Jeff, Danilo and M. Alcaraz, about the problems in Ecology related to the use (and abuse), of misleading terminology, several times derived from economical, engineering or medical disciplines, as for example in the case of the ecosystems services paradigm.

The detailed explanation provided by Danilo is excellent to define the status of a system, in terms of resilience, complexity and interactions balance: 1. Homeostasis; 2. Absence of disease; 3. Diversity or complexity; 4. Stability or resilience; 5. Vigor or scope for growth; 6. Balance between system components. And this definition could be enough in Ecology to assess the status of one ecosystem. However, if you try to assess the same ecosystem in terms of "benefits provided only for human species" the assessment could be totally different, and, of course, totally biased.

As principle, I don't like the indiscriminate use of words coined in one discipline, to evaluate components described by other different disciplines. The philosophical issues, already underlined by Wittgenstein, are always present in all disciplines of Sciences.

I would consider alien invasive species as well..

Hi, It is very difficult to assess the health of an ecosystem and defining a healthy ecosystem.........However, personally I feel a healthy ecosystem is the one which ensures normality in production and productivity with no sign of conflicts in and around.

Hi, It is very difficult to assess the health of an ecosystem and defining a healthy ecosystem.........However, personally I feel a healthy ecosystem is the one which ensures normality in production and productivity with no sign of conflicts in and around.

Living in California which is perhaps the sickest ecosystem on the planet with an almost 100% conversion of the native understory to over 1,000 European weeds.  From my perspective, it is the absence or presence and diversity of the non-forest understory.  

Grasslands  world-wide usually get damaged first by humans, so if your native grasslands are in good shape, that could be a first measure.  What you want to see is 100% native cover, zero exotic cover, and as few bare-soil areas as possible, with species diversity comprised of about 50% perennial grass cover and 50% broadleaf herbaceous plant cover.  

Surprisingly, if you look at the photos at http://www.confluence.org by 2015, the grasslands worldwide have been truncated to only a few grass species, and the wildflowers and non-grass plants are largely missing.    

Dear Wilbert,

This theme is very current and has been studied by several research groups, giving rise to scientific journals and various publications.

The health of ecosystems is closely linked to the survival of human beings on our planet, using the natural resources necessary for survival.

Sending down the link to an article on the subject.

http://www.esajournals.org/doi/pdf/10.1890/EHS14-0013.1

Good job,

An ecosystem is said to be healthy, or in other words which is more preferably in Ecological studies "stable" when all the ecosystem processes such as net primary productivity and nutrient cycling are well functioning. But also plant , animal and microbial species diversity at all spatial scales, and the proportion of invasive species.  

Before deciding on what criteria are necessary to determine the healthiness of an ecosystem it is important to first define the parameters of your definition of ecosystem health. A healthy ecosystem may include different factors depending on the scope of the question and type of ecosystem. Are we looking solely at the ecological functions being met? Or do we assess the stability and sustainability of a system to weather different environmental stresses? Are species within the system functioning in their role to their full potential? What is the role of the ecosystem in the biome in which it resides? Ecological health assessments can be conducted to give a general assessment of an ecosystem’s status, but these assessments are highly subjective and, depending on the size of the ecosystem you are considering, very difficult to accurately survey. Ecosystem health is a challenging concept with no real right or wrong approach.

In a nutshell - complexity - measured in as many ways as possible: eg biodiversity, using several different indices, and as many taxa as possible.  Also structural complexity (layering, etc).  Plus the flows of  matter and energy, as suggested by several other correspondents.

Dear Wilbert,

Even if it's note exactely the subject, may be some papers of Jame Aronson on restoration ecology could be useful for you

Best wishes

PS: Alexandre my bacteria are agree with yours!

That really depends very much on the perspective. Overall it would be much better to look at ecosystem function, i.e. does the ecosystem provide / maintain a certain function. "Healthy" is most often used from an anthropogenic perspective, and often is used to refer to "undisturbed" ecosystems. However, most ecosystems on the globe have for a long time been under anthropogenic impact, so "healthy" never should be used synonymous to "undisturbed" or "pristine," since even "pristine" humid forests or cloud-forests, e.g. in South America, at a closer look, show distinct human influence, especially pre-Columbian influence. Even "ecosystem function" has an anthropocentric undertone. So lastly, "ecosystem stability" or "ecosystem resilience" would be better to look at, and this should include disturbance and its effects, because disturbed systems often in fact show a higher diversity than systems that appear to be stable.

Here is a piece from the Resilience Institute:

ECOLOGICAL RESILIENCE

There is agreement in the literature that Crawford (Buzz) Holling first introduced the concept of resilience to ecology and the environment.  He promoted the use of systems theory and modelling, and is credited with the introduction of ecological economics, the adaptive cycle, panarchy (understanding transformations in human and natural systems) and resilience to ecology and evolution.

In his 1973 paper, Resilience and Stability of Ecological Systems, Holling defined the resilience of an ecosystem as the measure of its ability to absorb changes and still exist. He compared and contrasted the concept of resilience with the notion of stability, which he defined as the ability of a system to return to its equilibrium state after a temporary disturbance; that is the more rapidly the system returns to its equilibrium, the more stable it is. He concluded that resilience and stability are two important properties of an ecological system.

Some ecologists, such as Richard Klein, argue that ecosystems are dynamic and evolve continuously in response to external influences taking place over a period of time. In a conceptual study of the resilience of the Dutch coastline, Klein points out that coastal systems are continually changing, so no original or equilibrium state exists. Moreover, the changes are not isolated events from which the coastal systems may not recover, but are ever-present and occur at different times and in different ways.

In spite of its lack of specificity, the concept of resilience is considered useful in understanding the behaviour and improving the management of ecosystems. Academic networks and organisations such as the Resilience Alliance and the Stockholm Resilience Centre aim to advance our understanding of complex social-ecological systems and generate new insights and tools to improve the management practices and long-term sustainability of ecosystems.

The Resilience Alliance (www.resalliance.org) is a global network of scientists and practitioners from a wide range of disciplines who collaborate to explore the dynamics of social-ecological systems. The Stockholm Resilience Centre (www.stockholmresilience.org) is a joint initiative between Stockholm University, the Stockholm Environment Institute, and the Beijer International Institute of Ecological Economics at the Royal Swedish Academy of Sciences.

With human dominance on earth, we might think of virtually all ecosystems as coupled human-environmental systems (CHES) both dynamic and resilient and containing some degree of human footprint.  So as many have said above, its the dynamacism and functionality that count, with resilience of the CHES as the center piece.  What I quickly said here is just a bare touch of what is emerging in the new field of sustainability science.  The term, as some have alluded to here, should probably be abandoned.  Regards,

Mike Weinstein

Who is going to use the assessment of "health" and for what purpose?

If the assessment is for academic research then there are already plenty of good answers; if you want to use the assessment as "leverage" in discussions on policy, management, conservation - then you might want to think in terms of ecosystem services. I'm not a fan of ES, but for the right audience in the right context they can be a useful tool.

Hello,

I'm not sure what I can add! However if you are asking what constitutes a healthy (naturally functioning) ecosystem, using indicators should help quantify the more cryptic questions being posed. e.g. for a forest - primary productivity, fragmentation and heterogeneity, species occurrence... Remote sensing and analysis in GIS are useful in assessing change that can effect the complex cycles, dynamics, fluxes and interactions that drive ecosystem functions. Skidmore et al., 2015 discuss these "essential biodiversity variables" that, using satellite remote sensing, can be measured in their paper 'Agree on biodiversity metrics to track from space' in Nature, vol. 523, 403-405.

It is important to identify the individual components

A healthy ecosystem is that possess ecological balance in between the trophic levels in terms of energy flow( functional aspect) and interactions between the biotic and abiotic factors (structural aspect).

This article can be useful.

For non-riparian terrestrial systems:

1.) SOIL NUTRIENTS. Adequate soil nutrients levels and soil carbon for local native plant seedlings survival.  Many places on the planet, the domesticated grazing animals have robbed the soils to the point that native seedlings of some species cannot survive after germination.  

2.) NUMBERS OF SPECIES. A fecund-diversity of local native species.  In many places on the planet, the arid and mountain grasslands have had their species "truncated" where the diversity of wildflower has been eliminated, to favor only a few of the desirable forage species.  It may go from over 100 species in an undistrubed relict area down to only a few dozen or less.   Or forested areas converted to grasslands and farm fields, like  the temperate and tropical parts of the planet.  North Africa, central and southern Europe, the UK, India for example.

3.) BARE SPACES & EXOTICS. Lack of bare spaces and bare soil, and exotic plants.  When I look at the images from the http://www.confluence.org project, it is now very difficult to find good examples of "healthy" ecosystems anywhere where there are humans with grazing animals, or farming?  

I just flew from New Mexico to California yesterday, and I felt like the Greek Diogenes looking out the window, searching for a healthy ecosystem over thousands of square miles of the Southwest?

Dear Wilbert Aureo

I dont know this questions. my filed is mineral processing and mine environment.

Best Regards, Sajjad

An ecosystem is healthy if it is rich in biodiversity.

 Dear Wilbert,

The health of ecosystems is very complex, but I believe we have well-maintained environments in order to default and allow comparison with other areas.

I found that this area of research has been widely studied, however, I am sending you the link to some older works that are the basis of this research area.

1 - Concepts of forest health: utilitarian and ecosystem perspectives 1994.

2 - Healthy Ecosystems: An Evolving Paradigm David J. Rapport, 2006

I hope I have helped you.

Claudio 

Dear Wilbert,

I also send the link of an older work underlying this research area.

Assessing ecosystem health, DJ Rapport et al., 1998

I hope I have helped you.

Claudio

Ecosystem health encompasses species richness as well as species evenness, both of these are results of the  disturbance regime a particular site faces and varies as per locality factors. Their are multiple indicators through which one can check . For example; Natural regeneration of forest tree species and number of healthy juveniles of wild animals in that forest , presence of diverse microbes, VAM diversity and soil fauna could be counted as  indicator of ecosystem health. 

The list is long.

First a particular "ecosystem" must be defined first, and then intact or pristine examples must be measured as to the number of species and the species cover for each, to provide a physical constant.  Let's call that the "Golden Ecosystem Constant".  Then when working in other areas of that same ecosystem, you can do the same measurements, and gauge it against the Golden Constant.  

It is like when we go and get a blood test, for humans there are constants for a healthy human that our own individual tests are measured against.  Without a "healthy" constant for a particular ecosystem, there is no way to accurantly judge the health of any other part of the same ecosystem.

This also gives us a measurable way to judge health, instead of arbitrary judgement calls, like those that have been made for decades in the past.