If we take a global view, the main problems affecting the world's soils are (in order of apparency) erosion, compaction, reduced infiltration, loss of water holding capacity, loss of nutrients, loss of organic content, loss of biodiversity, change of morphology (sand/silt/clay) and loss of sink capacity (short-term for greenhouse gases and long-term for complex carbon). These properties are related to one another of course, so a significant change in one relative to a control site in a (preferably) pristine state, should be reflected by changes in others. Also, changes in land-use which modify or simplify the above-ground vegetation are likely to be reflected in soil properties, although separating human impact from natural variations and successions is often difficult. Erosion, bulk density, infiltration, water-holding capacity and organic content (%C) are quite easy to determine by standard procedures. Going beyond this requires analyses of soil physics, chemistry and morphology; unfortunately almost 100 parameters are routinely determined when soils are fully characterised, so the choice of those used depends on the issues at hand and access to appropriate laboratories. Similarly, it is estimated that more than 1.5 million species of soil organisms have been described (or at least recognised), such that a complete inventory of any single sample would require the attention of many taxonomists. However, some idea of soil biological health can be obtained by looking for representatives of key functional groups. The current list of such groups is: primary producers, herbivores, ecosystem engineers, litter transformers, lignocellulose degraders, predators, microregulators, microsymbionts, pests and prokaryotic transformers.

In the context of tropical soils, more information can be found in

Anderson JM, Ingram JSI (1993) Tropical Soil Biology and Fertility: a Handbook of Mehods. CAB International.

Moreira, FMS, Huising EJ, Bignell DE (2008) A Handbook of Tropical Soil Biology: Sampling abd Characterization of Below-ground Biodiversity. Earthscan (now Taylor and Francis).

The approach I use is to look at the soil biota because they are integrators of everything happening to the soil. Compare your impacted sites to reference sites to get an idea of the differences. You can also use a gradient approach of "increasing impact". The biota used for this sort of question are usually arthropods (like mites) or nematodes as they tend to be the most abundant and diverse groups.

Microbial biomass (C, N, P) be a variable to be studied. This allows us to observe the transformations of organic matter due to changes in land use. The sampling intensity depends on the type of study. This can be calculated from the number of samples possible in a particular area or defined according to the literature. The ideal is to use the maximum possible samples. However, samples or sample areas can be divided according to the land use. Samples can be obtained from plots with defined area. The use of plots facilitate statistical analysis. The sampling the plots can be made using between 5 and 10 points. These sampling points are then mixed to form one composite sample per plot. In the case of sample depth should use samples every 10 to 20 cm. With the use of different depths must use an analysis using a mixed model.

One suggestion would be to use 5 plots per study area with soil samples at different depths. In this case, make periodic collections and use a mixed model for analysis.

Microbial diversity is critical to the ecosystem functioning as a result of the many processes for which microbes are responsible, such as decomposition and nutrient cycling, soil aggregation, and pathogenicity. I use biochemical- and molecular-based techniques to study the structural and functional diversity of microbes in soils that have been subjected to agricultural chemicals or cultural practices such as minimum tillage, cover cropping and rotation. Fatty acid methyl ester analysis (FAME) and phospholipid fatty acid analysis (PLFA) are utilized to detect functional changes in microbial communities. Denaturing and temperature gradient gel electrophoresis (DGGE and TGGE) are used to follow structural changes in soil microbial populations. Other PCR-based approaches such as t-RFLP analysis are also used in my lab to study microbial diversity based on DNA polymorphisms. Technologies that employ pyrosequencing and metaproteomics are currently being developed in my lab. We use rhizosphere soil as opposed to bulk soil samples since the latter are far less sensitive in terms of the quantitative and qualitative differences that can occur between treatments. Our data are usually subjected to principal component analysis and cluster analysis.

Human impact on soils is very much related to organic matter (OM) content of the soil which in turn drastically determines structural stability as shown by the mean diameter of the soil aggregates. Typically the soil decreases its OM with human intervention. In our experience the most sensitive test for this is the mean diameter of the aggregates. Some of our publications showing this response are on REARCH GATE.They also show how to sample (soil depth and intensity).

The efficiency of the technique applied depends on the site characteristics.

Our methodological approach was usefull in the studied context, as described in this article.

Good luck,

Gianni

If the previous human activity is agriculture, then it is likely that there will be increased concentrations of phosphorus at the surface. Also, you can clearly see if the soil has been previously tilled by simply observing the horizonation and morphology (Ap horizon). Obviously it is important to additionally sample areas that you know for a fact had little to no human influence, such as a forest; this can provide somewhat of a "baseline".

Your question is not easy to be answered since many approaches can be used and most of the researcher use the one most familiar to them. These points seem to be important in my point of view:

1) have a look to the species groups which have a high number of species and high number of individuals (e.g. spring tails, mites, earthworms, nematodes, myriapods etc.).

2) try to find out that the selected species groups can be sampled in sufficient numbers throughout the year.

3) choose two of them (if possible, two different feeding guilds.

4) measure addional soil parameters possibly associated with human impact (e.g. soil compaction, soil nitrogen).

5) and be aware that "undisturbed" referecne sites may be differ in many paramters not associatiated with human use.

Without getting into analytical specifics I think you need to consider carefully what it is you actually want to measure, e.g. anthropogenic impact on biodiversity. Even that is a huge topic let alone "human impact on soil". I can't think of a single soil property that can't be affected by humans and the effects can be positive or negative. For example, agriculture usually decreases soil organic matter but there are extreme examples of the opposite, such as the plaggen soils of the Netherlands, the result of centuries of intensive manuring and composting. So, I think that until you narrow it down a little, this sounds more like the title of a book than a diagnostic test.

I agree with Lewis and Thomas, that there are many, many methods that could be applied here and even more different things that you could look at for 'human impacts' in the soil. A little more direction here would be helpful. What type of human impact changes are you looking for? Is it agriculture, or land use, or global change? Are you looking for things like soil fertility, or contamination with heavy metals, etc? This would really help you get relevant answers to your question.

My first reaction is to look for elevated soil N and P levels as an indicator of local agricultural impact or atmospheric deposition. This presumes that you have some understand of what to expect in a natural system of this type. But as others have suggested, there are lots of ways human disturbance might be manifested and more information is needed about the suspected disturbance. Atmospheric pollution? Agriculture? Mining? Habitat fragmentation? Species introductions?

Dear Jeremy,

Regarding your question "How would one test soil for indicators of human impact?" as you can see above there are a lot of ways that you can follow the changes using soil biota indicators. Yourself - work on spiders that can be use as indicators - by comparing with natural system if we are talking about natural reserves. First of all defined the study site, screen the biota components, etc. is the impact seasonal ? In order to help you should defined your question !! be goal oriented.

Wish you a great success.

Human impact is so varied that it seems to me impossible to indicate it without a clearer assessment of what you mean by human impact. Soil pollution by heavy metals and other pollutants which are detrimental to soil biological activity (mostly microbial but not only) results in a accumulation of organic matter, provided vegetation is present on the site. In this case the humus form turns to an organic layer made of an accumulation of undecayed plant debris. Other cases of human impact are compaction, commonly found under intensive agriculture and also now in forests, due to heavy traffic by vehicles. In this case other indicators can be found, for instance in plants or in physical signs of waterlogging. More generally, what could be the manner man impacts the soil (negatively, I suppose), it results in an impoverishment of soil food webs (soil trophic networks), i.e. in a lack of functions: litter decomposition and soil aggregation being the most easy to perceive directly on the field (whatever the climate and the soil type) without any refined and costly laboratory investigations.

I think you launch your task from the most important point, i.e. philospohy of application and sampling techniques.

I think my paper, wich you can see as a full text

https://www.researchgate.net/publication/236880752_Sampling_techniques?ev=prf_pub

will be fine for beginning.

Good luck,

Fedor

Article Sampling techniques

I would like add the following: Look for and quantitate things not natural to soil, lke plastics, bricks, concrete, size stones, metals etc.

If we take a global view, the main problems affecting the world's soils are (in order of apparency) erosion, compaction, reduced infiltration, loss of water holding capacity, loss of nutrients, loss of organic content, loss of biodiversity, change of morphology (sand/silt/clay) and loss of sink capacity (short-term for greenhouse gases and long-term for complex carbon). These properties are related to one another of course, so a significant change in one relative to a control site in a (preferably) pristine state, should be reflected by changes in others. Also, changes in land-use which modify or simplify the above-ground vegetation are likely to be reflected in soil properties, although separating human impact from natural variations and successions is often difficult. Erosion, bulk density, infiltration, water-holding capacity and organic content (%C) are quite easy to determine by standard procedures. Going beyond this requires analyses of soil physics, chemistry and morphology; unfortunately almost 100 parameters are routinely determined when soils are fully characterised, so the choice of those used depends on the issues at hand and access to appropriate laboratories. Similarly, it is estimated that more than 1.5 million species of soil organisms have been described (or at least recognised), such that a complete inventory of any single sample would require the attention of many taxonomists. However, some idea of soil biological health can be obtained by looking for representatives of key functional groups. The current list of such groups is: primary producers, herbivores, ecosystem engineers, litter transformers, lignocellulose degraders, predators, microregulators, microsymbionts, pests and prokaryotic transformers.

In the context of tropical soils, more information can be found in

Anderson JM, Ingram JSI (1993) Tropical Soil Biology and Fertility: a Handbook of Mehods. CAB International.

Moreira, FMS, Huising EJ, Bignell DE (2008) A Handbook of Tropical Soil Biology: Sampling abd Characterization of Below-ground Biodiversity. Earthscan (now Taylor and Francis).

Look around your study sites and nearby areas carefully and through visual observation try to identify places that are undisturbed or rarely disturbed. Now, take soil samples from both disturbed and un-disturbed land and compare depthwise (0-15 cm, 15-30 cm) particle distribution. In case of disturbed land particle distribution in two different soil depth may not be so much different as in undisturbed land.

For sampling size and pattern you must go through a standard book on soil sampling (e.g. Soil samping and methods of analysis, Eds, Martin Carter, Lewis publishers) and decide accordingly.

One human impact in soil is fecal pathogens and facal bacteria in general. To test for them, you would extract DNA and test for the presence of various specific DNA markers using PCR. The soil samples could be kept in a cooler during transport to a lab, or frozen, or small samples could be stored in extraction buffer--depending on available facilities, distance and temperature. Extracting DNA quantitatively from soil is challenging--your results would not be reliably quantitative. Also, it's not well known how long DNA markers from human feces last. If you wanted to test for very old contamination, you could assay for sterols, bile acids, and the like (bile acids have been used to identify Roman latrines). Chemical markers such as caffeine and laundry brighteners are also used to indicate human sewage.

I completely agree with Noa Lincoln. You must first clarify the scope of your test or else we're just "shooting from the hip" with potential answers and methodologies. "Indicators of human impact" is too ambiguous and may be interpreted differently as seen by the comments.

If you're talking about interpretation via statistical methods you may consider using R, bays net, etc...for analysis. As for sampling, that's relative to the geology of the area, which can change aquifer flow, soil composition, soil chemistry, etc... Furthermore, does the client want matrix duplicates to test for interference, what is your budget, etc... All these things will define your procedures and project.

Again, more information the better.

I checked the soil microbiota before and after pesticide application and also u can use the heavy metals uptake by plants.

From my experience, the most reliable way to assess and to take decisions is performing a multidimensional analysis. First step: to tailor a scale of significance of all your parameters you need to analyze. Scale is suggested to go from 1 to 5, being 5 the top of the characteristic. Characteristics may be, for example: (abundance, reactivity, potential of pollution, etc.)

Second step: multiply all the values (marks you've given) from each element you want to assess (if you got 8 characteristics with assessments like 3, 2, 4, 5, 3, 2, 1, 4, then the multiplication will yield a figure like 2880 ). Then take the Log 10 of this figure and plot it. Do the same with every element you need to asses.

thirth. and final. compare all the values plotted and decide the order of significance of the elements to assess in your research. If it is still difficult to decide, you can also multiply every characteristic for a factor (significance factor is the sum of all the fractions of 1, and 1 is the total sum of the characteristics assessed by each element) This artifact will modulate the previous result, so you can decide not only by an absolute criteria, but also a relative one.

Good luck

Dear Jeremy. I think that when you ask for human impact, the question is very general. My suggestions are: 1. Take a look to the landscape and find places that present different degrees of perturbation, think about a gradient of perturbation, from the must perturbed place to the must preserved one. How many samples? Good question because it depends on the extension of the area (you can use maps). You need to think, for a good comparison, in the same number of samples along the gradient, lets think about 20 samples in each place, from 0-60 cm depth. 2. It is very important, if we are talking about landscape management, that you make observations about indicators like vegetation cover in each place you sample; soil erosion and compaction. 3. Very important too, what inhabitants think about the deterioration of the landscape? So I think is a good idea to applying a short questionary to know this things. Good luck.

Hi Jeremy,

What specifically are you looking for - historical input and early human activity, or more recent activity of local and regional anthropogenic input? Is there a particular site of interest or is is a broader survey of a large area? With suitable control sites and statistical analysis of a suite of chemical marker compounds you could quite easily address this issue. Specific Polyaromatic hydrocarbons indicate human input and can distinguish between petroleum or combustion origins. Modern sewage and effluent, as well as historical human settlements, can be traced using the analysis of a suite of faecal marker compounds such as bile acids and faecal sterols. With suitable negative (and positive) control sites and sufficient samples for correlation analysis and multivariate statistical analysis such as principal component analysis and hierarchical cluster analysis, you would be in a strong position to assess human impact from soil samples. Heavy metal analysis using a benchtop or even portable XRF analyser may also be appropriate. Bulk parameters such as PSA, TOC, TN etc are always good back up data to explain and possibly normalise your analytes of interest.

If it is simply soils you are looking at and depending on the time period you are interested in you will want to core or excavate, and fully log, the various soil horizons and sample from these. The sampling intensity depends on the specific question and amount of analysis/labour. For a spatial analysis I would suggest a minimum of 20 sampling stations, while if you plan in-depth analysis down a soil horizon, this would I assume have to be decreased unless you have a considerable amount of time. For a polluted site for example, a number of replicates in and outside the site may be suitable.

For trace organic analysis - solvent washed (ideally furnaced at 450 deg Cel) glassware and sampling equipment is recommended. As Katherine mentioned above soil bacterial diversity and abundance could also be helpful and sterile storage either frozen or at 4 degrees (if culturing is intended) would be needed. For PCR work frozen soil samples in sterile and furnaced containers would be suitable but usually separate samples are easiest and less risk. You could also consider more straightforward phosplipid fatty acid analysis to look at bacterial biomass abundance and diversity, and changes thereof due to human input.

Good luck.

Good question. Actually there are many indicators of the impact of contaminants in soil. However it is difficult to say that one of them can represent the impact on humans.

The results with sentinel organisms are not a guarantee.

In my view the best indicators of impact are the most complex, such as decomposition of organic matter, biodiversity, soil enzymes, respirometry, among others. In general these parameters are related to functions and processes that involve many variables and are more difficult to analyze. The most simplest indicators must accompany this data for better interpretation.

There are some qualitative measures that would give you a sense of potential impact - presence of roads, trails, loss of understory, reduced or missing litter layer, reduced or missing A horizon. Often in a landscape context you can find gradients of high to low disturbance or impact and use these to contrast and compare. Professor Bignell's suggestions then clearly move one from a qualitative description or evaluation to a quantitative and perhaps even an understanding of how to prioritize restoration.

Many of the previous researchers have provided good answers to your question! Indeed the most prominent impacts to soil by humans result from agriculture or forest clearing (in rural areas), where as, in urban or periurban areas these may be pollution and contamination with various toxic compounds and heavy metals. So, first you need to identify the scope of your research and select potential indicators appropriately.

If you are interested in agricultural or land use change impacts, you could consider key parameters like, pH (acidification due to use of fertilizers), SOC (reduced organic matter content due to intensive cultivation or changes in vegetation density), porosity and available water content (changes due to compaction and cultivation as well as organic matter), and so on.

Dear Jeremy,

Please give us more details about the types of human impact you are suspecting to occur in the Caribbean sites you are investigating, in order to avoid blind answers of any kind...

Caffeine is a good indicator. Ogunseitan wrote a paper about it.

Unless the question is more specific its difficult to give suitable answers.

Its very important to find a "pristine soil" of the same type and texture (or preferably from the same region...may be hard to find) and analyze it alongside the spatially and temporally resolved contaminated soil samples. the spatial and temporal resolution will be site specific and the best judge is the sampler himself...in this case depending on the intensity and nature of anthropogenic influence. Depth of sampling is important if you are trying to analyze heavy metal leachability...or soil-profile...you may find many literature on these aspects.

If you are wanting to measure organic matter then I guess you will have to have proper storage facilities. For...elemental analysis only (like with XRF) you just have to air dry....grind...make pellet or put in cup and analyze.

If the main motivation is anthropogenic influence...you can compare the data of contaminated soil with that of the pristine soil...and also refer to EcoSSL of the USEPA at their website...just google for EcoSSL...(Ecological soil screening limits).

Dear Dr. J. Miller:

I have sent you message about your question.

Best regards.

Ma. Teresa Rodríguez-Salazar

One more guess: harmonised human biomonitoring surveys in Europe

http://www.eu-hbm.info/democophes

Human impact on soils can be positive or negative. Positive is e.g. good agricultural management, negative is soil degradation, mainly: erosion, compaction, salinisation, loss of biodiversity, carbon content, etc. All these degradation types create in soil typical (not natural) properties, e.g. compacted soils have high bulk density (higher than typical for them in natural status) - it has to be always evaluated in context with soil texture -e.g. bulk density of 1.4 g.cm-3 is fine for loamy soil and critical for clayey soils, ... Typical for human impact can be changes in soil profile - e.g. sharp horizontal line between A and B or deeper horizons due to ploughing, in some cases, e.g. dumping places the particle density can be higher than typical for natural soils, etc.

I would check what kind of human influences are on the assessed place (agricultural, soil degradation...) and the typical performance for them.

Dear Miller

I've sent you a message with some answers.

Best regards

Ricardo

Measure soil compaction.

Frank

Yes, this is an attractive synthetic indicator of soil biological activity

We are developing easy test for distinction tillage and no-tillage soils (see attach).

We are developing easy test for distinction tillage and no-tillage soils (see attach).

...

As a historical perspective and an interdisciplinary approach soil formation under different land use shows the impacts of past land managment on soil formation process therefor soil formation is a good indicator.

According to my knowledge - soil biota community, composition, diversity and trophic relation etc.- could be one of the best bioindicator.

I agree that to achieve such a goal a interdisciplinary and a holistic approach is necessary.

Sometimes, measuring Cs-137 (Cesium-137) or any other unnatural radioactive isotopes in appropriate conditions and in special depths of the soil profiles, can be used to study some time dependent impacts of human in the recent decades, but not for all kinds of human impacts.

I attach some cites about scientific articles regarding this topic. I hope this helps.

.-Seybold, C.A., M.J. Mausbach, D.L. Karlen, and H.H. Rogers. 1998. Quantification of soil quality. In Soil Processes and the Carbon Cycle. R. Lal, J.M. Kimble, R.F. Follett, and B.A. Stewart, eds. CRC Press, Boca Raton, FL.

.-Karlen, D.L., M.J. Mausbach, J.W. Doran, R.G. Cline, R.F. Harris, and G.E. Schuman. 1997. Soil quality: a concept, definition and framework for evaluation.

Soil Sci. Soc. Am. J. 61:4–10.

.-Andrews, S.S., D.L. Karlen, and J.P. Mitchell. 2002. A comparison of soil quality indexing methods for vegetable production systems in Northern California.

Agric. Ecosyst. Environ. 90:25-45.

Dear Jeremy,

Thank you for your good question. Unfortunately the information you have given is not complete. Data interpretation will depend on what you are looking for in your research questions i.e If you are looking for soil fertility, then you will need to measure both chemical and physical properties of your soil. The sampling intensity will also be dictated by the land size and the agro-ecological zone of the area where you are carrying out your study. The more diverse your study area the more samples you need to take. As I mentioned, why you are carrying out the study will influence the sample size, replications and the data to be collected.

Thanks to all for your comments, insights, and references. It's probably high time for me to add some details to perhaps focus the discussion. The aim of this project is to integrate the biodiversity data (which I'm familiar with) with an assessment of human activity (which is new to me). The islands support a range of human activities, including industrial, agricultural, and residential areas, plus protected park lands including cloud forests. From the soil analysis, we want to derive an index quantifying human impact. With both biodiversity and human impact data from all these sites, we will be able to address some interesting questions about sustainability and development, and investigate some specific responses of biodiversity to human activity. So what we want from the soil data is an honest indicator that quantifies human impact. I think of this like a forensic detective. How deep is the human footprint in each sample site? So the first thing to consider is what evidence might humans leave around the landscape? There are roads, cars, and a petroleum way point for oil tankers, all of which I imagine might produce hydrocarbon particles that will settle across the landscape with concentrations on average higher near the source. Heavy metals like lead might also be detectable. There is crop and livestock agriculture. Fertilizers and animals wastes might be associated with high levels of nitrogen, phosphorus, carbon, and other nutrients. I have also heard that bacterial and fungal biomass might be useful for this (high levels of bacteria associated with high nutrient environments like farms and high levels of fungi associated with low available nutrient environments like forests). Also associated with agriculture might be pesticide residues, which must leave some particular chemical signatures behind. That's about as far as I've got so far. The next step might be to convert this narrative into a technical and specific list of compounds that can be quantified in the laboratory.

Dr. Heitkamp suggested I take on a collaborator with experience in soil science. Indeed! If you are or know of a soil scientist with the expertise and motivation to join this project, please contact me for further details and discussion.

I do believe that the most important thing affected by human activities is soil biomass. Biomass is affected by all physical and chemical applications. Changes of soil biomass over time is the indicator of how good we are dealing with soil.

Following your further clarification, i think it is important to consider the depth of sampling when quantifying soil properties that are sensitive to anthropogenic activities. Usually the human impact can be observed in the first 20 cm without confounding factors inherent to the soil, e.g. soil series. So you might need to quantify properties such as bulk density, infiltration rate, hydraulic conductivity, soil organic carbon, nittrate, phosphorus etc at depths of up to 20 cm. Regarding the number of samples, it depends on the size of the field,but the more you can get, the better.

Dear Dr. Jeremy,

Going by your scheme, it seems you might need some temporal resolution for the sampling activities....to see the anthropogenic effect on the soil over time....since you will start sampling with the soil already affected to some degree, i.e. if you want a fair index.

From the geophysical and petrophysical points of view soil samples may contain many indicators of human activity: radionucleids, different kinds of industrial pollutions, particles of various metals, garbage of different composition, etc. For detection of the concrete type of contamination (pollution) different geophysical (physical, chemical) methods are applied.

Legacy and current pesticide use in agricultural lands have had a major impact. There are numerous papers documenting this.

It sounds as though you are looking at two issues. The first is the impact of human activities on biodiversity, soil productivity and so on. The second is actually linking it to human activity. In other words, there is the need for information on soil "quality", which can be impacted on by human activities and natural events.

Human activity would also leave chemical tracers which could then be used to identify it. Typically good tracers are compounds, elements and isotopes which have no natural origin and are persistent in the medium being analysed. Pesticides have been suggested. Other possibilities include artificial radionuclides - distributed by atmospheric weapons tests and nuclear accident, CFCs and pharmaceutical products (both therapeutic and recreational). The choice depends on the environment that you are working in.

There are more researchers give much important ideas about your quesition. I am also very interesting your question. I think you can get samples from the place and extract pollen form the soil. If there is very high percentage Gramineae in the pollen spectrum, and there are much Gramineae grain size more than 40 μm, mybe where was disturbed by human. And the another question is when the human beginning live or rehabilitate the place , we can get the age by Pb210 or AMS 14C. Anyway, if you want get more specific suggestion about than, I think more specific information about your research aim are need.

human activity like mining is a serious threat as it leads to development of waste lands;

Total waste land in a country itself is a indicator of impact

developing waste lands is all together a different aspect