Why are the implications of ecological restoration on microarthropod diversity important to understand?

Soil organisms are phylogenetically diverse, trophically heterogeneous, functionally variable, assorted in size, dissimilar in longevity, variegated in morphology, adapted to different soil horizons, but united in their reliance upon death.  That is, soil organisms are similar in that their foodwebs rely upon the processing of detritus – leaf litter, coarse woody debris, the carcasses of dead animals and so forth (Coleman et al. 2004).  Collectively the action of organisms within detrital-based food webs results in the breakdown of dead organic matter and the mineralization of organic compounds making key nutrients available to the living (Swift et al. 1979).

To illustrate the enormous diversity of soil organisms, I recently calculated that in a typical walk along an Illinois woodland path each and every foot fall lands upon the bodies of 270,000 protozoa, 135 mites, 3 springtails, and one or so large earthworms (Heneghan 2011).  These are representative of 30 soil species of which up to half may be previously undescribed by taxonomists!  Scaled up there can be at least 200 species of soil insects and 1000 species of soil animals in every 1 m² of soil. The calculation is based upon an extensive review of soil biodiversity (Giller 1996)

Since the soil fauna are a major contributor to the diversity of many sites of conservation interest it might be expected that projects targeted at biodiversity conservation would include a consideration of these organisms.  However ecological restoration, that branch of environmental management devoted to the rehabilitating of degraded habitat, has paid scant attention to soil organisms (Callaham et al. 2008, Heneghan et al. 2008).  This gap in knowledge and practice is significant because soil organisms are a very large component of the biological diversity at many sites and because the regulation of nutrient availability exerts a large influence on the diversity in plant communities which in turn influences the diversity of animal species including belowground ones (Anderson 1975, Lussenhop 1992, Coleman and Whitman 2005). 

Concern for the conservation and restoration of decomposers and soil communities is made more urgent because soils are vastly affected by global change (the interrelated problems of climate change, nitrogen pollution, invasive species introduction and so forth).  Invasive species in particular can have dramatic implications for soils, either directly when soil animals (e.g. earthworms and isopods) are introduced into a site or indirectly when plants invade (Wolfe and Klironomos 2005, Heneghan et al. 2006, Heneghan et al. 2012).  Modification of plant communities result in altered assemblages within the soil, and these in turn will have implications for ecosystem processes that can determine the successional trajectories of plant communities.  

Some References

Anderson, J. M. 1975. The enigma of soil animal species diversity. Pages 51-58 in J. Vanek, editor. Progress in Soil Zoology. Akademia Press Prague.

Callaham, M. A., C. C. Rhoades, and L. Heneghan. 2008. A Striking Profile: Soil Ecological Knowledge in Restoration Management and Science. Restoration Ecology 16:604-607.

Coleman, D. C., D. A. Crossley, and P. F. Hendrix. 2004. Fundamentals of Soil Ecology. 2nd edition. Academic Press.

Coleman, D. C. and W. B. Whitman. 2005. Linking species richness, biodiversity and ecosystem function in soil systems. Pedobiologia 49:479-497.

Giller, P. S. 1996. The diversity of soil communities, the 'poor man's tropical rainforest'. Biodiversity and Conservation 5:135-168.

Heneghan, L. 2011. Why Should We Care about Restoring Decay Loving Decomposers? . Restoration News Midwest 4:6-9.

Heneghan, L., F. Fatemi, L. Umek, K. Grady, K. Fagen, and M. Workman. 2006. The invasive shrub European buckthorn (Rhamnus cathartica, L.) alters soil properties in Midwestern US woodlands. Applied Soil Ecology 32:142-148.

Heneghan, L., S. P. Miller, S. Baer, M. A. Callaham, J. Montgomery, M. Pavao-Zuckerman, C. C. Rhoades, and S. Richardson. 2008. Integrating Soil Ecological Knowledge into Restoration Management. Restoration Ecology 16:608-617.

Heneghan, L., C. Mulvaney, K. Ross, L. Umek, C. Watkins, L. M. Westphal, and D. H. Wise. 2012. Lessons Learned from Chicago Wilderness: Implementing and Sustaining Conservation Management in an Urban Setting. Diversity 4:74-93.

Lussenhop, J. 1992. Mechanisms Of Microarthropod Microbial Interactions In Soil. Advances In Ecological Research 23:1-33.

Swift, M. J., O. W. Heal, and J. M. Anderson. 1979. Decomposition in terrestrial ecosystems Blackwell  London.

Wolfe, B. E. and J. N. Klironomos. 2005. Breaking new ground: Soil communities and exotic plant invasion. Bioscience 55:477-487.

Great Oppiella nova Census 2012: Kerosene Extractions

Sample Kit (these are available at the Env Science desk if any DePaul students want to help us sample for this project.)  Please contact me at lhenegha at gmail.  Or drop by 203 McGowan S.

DePaul Undergraduate Amanda Henderson taking sample in DePaul Urban Garden

Sample transferred into contained in lab (stored in 70% alcohol until critters can be extracted)

Sample is sieved in 150 u sieve - retaining mites but getting rid of small particles.

Small amount of kerosene added to sample - the soil critters float in kerosene.  Other parts of sample settle out

Rotating sample to mix the kerosene throughout the sample

Kerosene and arthropods are pipetted into sieve and rinsed in ethanol and placed in petri dish 

Amanda inspects sample under binocular microscope.

Oppiella nova - pictures taken in a previous photo shoot in the Heneghan lab.

For more on this project please visit here

A Note on the Extinction of Fire in Chicago

When they occurred, fires on the Midwestern prairies were so great that the conflagrations both terrified and exulted witnesses. Albert, Prince of Wales, who would later become King Edward VII of England saw one when he visited Dwight, a small Illinois town located in Livingston County in the center of the state, in 1860. It provided an excellent supplement to the pleasures of the hunt. On his first full day of hunting Prince Albert bagged eleven and a half brace of prairie hens thus winning a bet for him against the Duke of Newcastle who killed three fewer. The prince had previously dispatched a screech owl. In his account of the visit Nicholas Woods reported that during the visit His Royal Highness not only had great sport with the prairie wildlife but he had been fortunate enough to see a prairie thunderstorm, a tremendous prairie fire and a prairie sunset.

The fire started during an evening thunderstorm before the hunters could return to the town. The fire started in three different places and though it seemed at first that the heavy downpour would quench the flames, nevertheless the fire moved on until the three fires joined together to create a great infernal wall. Close to the fire it was as bright as noon even though by then it was nightfall. The prairie wolves howled as they sped from the flame and the prairie chickens rose and fell back again upon the flames. Since the winds were heading away from Dwight the prince was in no danger and the company watched the flames indifferently.

Though the royal party was safe, not all have been so lucky in their encounters with prairie fire. David Turpie (1828-1909), a US senator for Indiana, describes how he became familiar with prairies in the 1850s.  Commenting on the natural history of the prairie “blue stem grass” he noted that as a consequence of how dry it became in fall, thousands of acres surrounding the farms of the region became combustible. To protect the farms, neighbors formed fire-brigades which rushed to the protect the most vulnerable properties.  They set carefully managed fires close to the places to be protected thus depriving the wild fire of its fuel.

The strategy of setting a fire line was standard advice for protection against a prairie fire even if one was heading towards you when you were traveling across the prairie. The smoke of such a fire darkens the sun and roars as it moves across the land. This is what you must do: ride your horse ten miles in advance of the fire lighting the prairie at a couple of points as you ride. As the fire takes off you can follow after on the scorched ground. The fire from which you are fleeing will hopefully not cross that ground.

At the height of the growing season when the grass may be taller than the horse upon which you ride, the fires are ever more dangerous and out-riding it will not be possible. The solution: you can slaughter your horse and climb into his disembowel carcass. If you are not cooked within the dead animal you can emerge some time later after the fire has passed.

Nicholas Woods described the sunset that so delighted the prince in 1860 in almost supernatural tones. It had a “glory which can never be described or understood by whose who have not seen it”. The prairie turned to gold, the sky pink and red, the clouds crimson and all was still. And then the color left the sky and the embers of that great fire could then be seen. So supernaturally unnerving did it seem to Woods that it was as if the sun had gone forever. For all of this, it was nevertheless the prairie that was about to be gone forever, and with it the vast conflagrations that had arrested a King-to-be.

Husserl as Systems Thinker: Machines, Intentionality and Emergence

In distinguishing between simple and complex intentional acts Husserl refers to machines.  “A compound machine”, he says, “is a machine compounded out of machines, but so compounded, that it has a total performance into which the performances of the partial machines flow, and the like is the case in regard to compounded acts.”  (LI V §18, p115).  It seems to me that it would be useful to extend the analogy further by referring to the property of "emergence" known in systems thinking.  The function of a machine (“a combination of rigid or resistant bodies having definite motions and capable of performing useful work.”) is often not entirely predictable based upon an inspection of its parts.  One might look for quite some time at the interdigitating cogs of a watch before one surmised that the telling of time was the function.  Perhaps a clearer example is that of water where its properties of flow and the properties of its states seem not to be predicable from an examination of the chemical properties of hydrogen and oxygen.  One wonders in a parallel fashion if something of emergence is at play in intentionality?  Husserl insists upon the unity of the intentional act in a manner that seems to be more than just a mere summing up of partial acts. 

I’ll be working on this over the coming weeks for the Husserl Logical Investigations seminar I am taking with Frédéric Seyler.  Primarily I will be reading Logical Investigation III On the Theory of Wholes and Parts and LI V On Intentional Experiences and Their Contents.  Any thoughts on resources? Robert Sokolowski has some useful papers on LI III onwards from the 1960s.

The homeostasis of happy and unhappy families

From Love and Other Catastrophes.

A characteristic of families is that they stick around.  Even the shitty ones.  Men and women may clamor and fret to find life partners – there are apparently industries based upon facilitating this endeavor.  And sure enough some are sundered very rapidly.  But most families do not fall apart, at least not immediately.  The endurance of coupled humans can be attributed to the set of homeostatic feedbacks that develop to stabilize them.  The uxoriousness of men, the doting of women, the clandestineness of their intimacies, the inextricability of their shared tasks, the loftiness of their originary vows, and the damp conjugations of the bedroom: all helming the established couple along the straight and narrow.  And when the satisfactions have stopped, heedfulness of the pocketbook, solicitude for the kids and maybe even the steely comforts of a dependable foe can keep the relationship on the tracks even as the furnace of love sputters out.  Of course, in the worst circumstances unhappy families are maintained by unspeakable acts being perpetrated upon those who dare not speak of them.  Read more of the essay here. 

Elephant Attack in Western Ghats

Excerpt from a piece of mine in Aeon Magazine 

A few years ago, this time with my friend and colleague Randall Honold, I travelled to a remote ecological reserve at the confluence of the Western and Eastern Ghats in south India. We were there primarily to look at wildlife, for these mountain ranges are exceptionally rich in species, many of which are found nowhere else on earth. The Western Ghats are one of the world’s dozen or so global hot spots for biodiversity. They were declared a World Heritage Site earlier this summer, around the time of my visit back to Ireland’s yew woods.

The Biligiriranga Hills Reserve is a day’s drive from Bangalore. As a place, Bangalore is all people, buildings, blatant smells, and phonic surprise. The Ghats, by contrast, are calm and subtle. Their demeanour is patient, abiding. It was months after the monsoon. The soils were dry and the air was clear when we travelled with three Soliga tribal guides into the heart of the reserve. The mammals of this reserve include deer — barking deer, sambar, and chital — as well as tigers and, famously, a herd of elephants.

We were made aware of the elephant population in an especially terrifying way. An agitated female charged us. She broke from the brush at dust-billowing speed, her ears flaring. Just when impact seemed inevitable, she swerved behind our white jeep. Before us was a lake. Behind us was an irate animal. The forest was hushed. With nowhere to go, we waited.

The elephant, viewed in the rear-view mirror, was all but motionless, although a tiny swaying of her body suggested that she was trying to resurrect an anger requisite to finish what she had started. Randall snapped a picture: ‘Objects in the mirror are closer than they appear.’ We sat more or less frozen, for this was the advice of our guides, one of whom later said that this was the closest he’d come to death-by-elephant in 40 years. Perhaps it says unflattering things about me that I felt bored, impatient even, in these minutes waiting for my demise. I cast a minuscule glance around the forest and noticed that the wall of vegetation from which the animal had exploded was made up ofLantana camara. This is an especially aggressive exotic shrub which has become a management nuisance throughout the Western Ghats. Spanish Flag, as it is commonly known, is native to the American tropics and is regarded as one of the world’s most invasive plants. Its flowers, as I noticed then, are exceptionally pretty. Having spent half a lifetime combating non-native shrubby vegetation in Ireland and in the American Midwest, it seemed fitting, though ultimately a little dispiriting, that a non-native shrub had just disgorged the raging agent of my death.

'She broke from the brush at dust-billowing speed, her ears flaring.' Photo by Liam Heneghan

After 30 minutes, the elephant retreated, as did we. Later, how we laughed. A leading hypothesis of our Soliga friends was that my hair, an outmoded snowy-white hank, had enraged the animal. A year later, when we revisited the field station at the Biligiriranga Hills Reserve with a group of students, the ‘elephant and the hair’ story was still going strong.

Stories persist. Ecosystems, however, do not. By this time the elephants had left this part of the reserve and were seen neither that second year nor the year after. The walls of Lantana had become even more pronounced. Vigorous before, the invasion had reached that critical point where, in some places at least, the plant was occupying so much space that wildlife was being crowded out. Along with the spread of the invasion, the diversity of plants is changing as well. And perhaps, if we embrace an ecological paradigm of disturbance and change, this is simply the way nature works, and nothing to be done about it. Or is there? 

Full piece is at Aeon Magazine