Outline of Essay: Being Unseen: the Gift of Oppiella nova

I

A strange gift from John Lussenhop – small colony of O nova

Commonest animal in terrestrial ecosystems

My first encounter with this animal 20 years earlier

Common but rarely analyzed.

Introducing main themes of essay: necessity, minute inspection of nature, amplified connection between humans and nature, commonplace rather than rarity.  Connection with Thoreau!

II

Classification of mites

Morphology

Predation on mites (ghoulish story of beetles feeding on mites)

Diversity of community

            Poor man’s tropical rainforest

            Illustration of temperate zone diversity

            Enigma/Enigma resolved

Ecological role of mites

III

Specifics on Oppiella

Diagnostic characteristics

List of exotic locations where it’s found

List of less exotic locations

What is known ecologically

Aggregation patterns

A lone O nova shows up at the mall!

IV

Association with people

No comprehensive studies of urban populations

Project with Amanda Henderson :Great Oppiella nova census 2013

22 billion O nova in Lincoln Park?

Hypothesis: diminished population because of leaf removal

V

Conclusions

Necessity: means essential but also intimately connected, rendering of serves

Broader concept of necessary

~3000 words

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

Being Unseen: The Commonest Animal You Have Never Seen

See details of this project over at City Creatures Blog.

In The Kingdom of Decay: How a Motley Team of Subterranean Dwellers Ransacks the Dead and Liberates Nutrients for the Living

The recently dead rot much like money accumulates in banks (until recently, at least), only, of course, in reverse.  A sage great-great-ancestor who had, for instance, set aside a few shillings for a distant descendant would, through the plausible alchemy of compound interest, have made that great-great-offspring a wealthy person indeed.  In contrast, after death a body-heft of matter accumulated over the course of a lifetime is hustled away, rapidly at first, but leaving increasingly minute scraps of the carcass to linger on nature’s banquet table.  It is as if Zeno had not shot an arrow but instead had ghoulishly slobbered down upon the departed, progressively diminishing the cadavers but never quite finishing his noisome meal.  The soils of the world contain in tiny form, scraps of formerly living things going back many thousands of years.  Perhaps these are the ghosts we sense when we are alone in the woods.

Before you rake away the final leaves of the autumn season, hold one up to the early winter light.  Those patches where you see sky rather than leaf are the parts that had been consumed live, nibbled away by insects or occasionally browsed by mammals.  But you may have to pick up several leaves to see any consumption at all!  The eating of live plant material is rarer than one might suspect.  It is almost as if most creatures, unlike us of course, have the decency to wait for other beings to die before they consume them.  Ecologists have wondered why this is the case, asking in one formulation of the problem “why is the world green?”  At the peak of the summer season the world is mysteriously like a large bowl of uneaten salad.  The world it turns out is green for many reasons but a compelling one is that plants generally defend themselves quite resourcefully.  The thorn upon the rose provides more than a pretty metaphor – this shrub knows exactly what to do with its aggressive pricks.  And if one can neither run nor hide nor protrude a thorn, you might manufacture chemical weapons.  Crush a cherry laurel leaf in your hand, wait a moment or so, and then inhale that aroma like toasted almond.  It’s hydrogen cyanide, of course.  “Don’t fuck with me” is one of the shrubbery’s less lovely messages.


Read on at 3quarksdaily

Four Conjectures on Soil Microarthropods and Ecological Restoration

In what follows I conjecture about soil organisms in the context of restoration projects.  This are listed below as C1-C4.  I concentrate here on soil microarthropods (primarily free-living soil mites and springtails), since these are the groups that my lab are most interested in.  I also have Midwestern systems in mind, but the remarks can probably be generalized.  These are for the most part empirically-based conjectures (a "empirijecture, if you will!)": there is not enough work done to be emphatic, but there is data emerging that supports each contention.

C1.       Soil microarthropods are hyperdiverse at most restoration sites.  This may be true even those that are considered to be in poor ecological health.  The number of described mite species globally is 45,000 or so and this may represent less than 10% of the total diversity.  To put this is perspective: if mite diversity got proportionate attention there would be over 100 consecutive "Mite Weeks" on Discovery for every one 'Shark Week”.  In the coming years we will get some real numbers at a variety of sites.  Expect no fewer than 200 species per hectare.

C2.       Factors that negatively affect plant diversity will also have adverse affects on soil organismal diversity.  Invasive species, fragmentation, nitrogen deposition, altered hydrology, climate change and so forth have implications for the soil environment.  In particular, factors that elevate decomposition rates may have devastating implications for soil animals.  This is because the decomposing litter, hosts the greatest diversity of soil arthropods.  I conjecture that in habitats where the litter layer has been reduced diversity is greatly diminished.  This may represent a vast unnoticed local extinction crisis.

Should We Care about the Conservation and Restoration of Decomposer Assemblages?

Soil organisms are phylogenetically diverse, trophically heterogeneous, highly variable in size, dissimilar in longevity, variegated in morphology, behaviorally divergent, adapted to different soil horizons, disparately pigmented, but united in their reliance on death.

By this, I mean to imply that an adequate study of soil ecology calls for interdisciplinarity on a scale that we are not especially good at.  That being said, the fact that dead things provide a foundation for these complex foodwebs has been enough for them to be functionally lumped together despite their multifarious attributes.  For the purpose of examining the fate of detritus this makes good sense.  Collectively the action of detrital-based foodwebs results in the breakdown of dead organic matter and the mineralization of organic compounds making them key nutrient available to the living. 

Restorationists need to pay attention to soil organisms both because they are a very large component of the diversity of most sites, and because the regulation of nutrient availability exerts a large influence on the diversity of plants and other components of the biotic community.  We all live in the shadow of the kingdom of decay.  Concern for the conservation of soil communities is made all the more urgent because soils are vastly affected by global change.  A warmer earth implies generally more rapid decomposition rates (when other factors such as moisture content of the soil remain constant).  Invasive species can also have dramatic implications for soils, either directly when soil animals (earthworms and isopods, for instance) are moved around, or indirectly when plants invade.

Soil Microarthropod Contributions to Decomposition Dynamics turns 100

According to a recent Google scholar alert (emails I receive when others have found use in their work for my publications), a paper I wrote with a number of colleagues connected with the Institute of Ecology at University of Georgia over a decade ago has now been cited in other works more than a hundred time.  This is not a huge number of course (citation classics in ecology are cited thousands of time) but nonetheless it is gratifying.  A lot of work went into the paper, and it involved fun but sweaty times in Costa Rica, Puerto Rico, and the Southern Appalachians where I examined decomposition rates of leaf litter (there was one common substrate - Quercus prinus - across all sites).  I can measure out the cost of this paper in bot-flies in my flesh, but that's another story!

As far as I can tell when people want support from the literature to support the overwhelmingly obvious statement that decomposition rates are higher in the tropics than in the temperate zone they cite Heneghan et al 1999.  Another less obvious outcome of the work has rarely been discussed and that is the observation that in warmer and wetter parts of the world the influence of soil critters can becomes quite important in determining decomposition rates.  Small differences in the assemblage structure of soil biota at different sites can have an influence on decomposition rates and on the rate at which nutrients become available in the soil.  In the graph above the CWT site is a temperate one (Coweeta), that LUQ site is Luquillo Forest in Puerto Rico and the LAS is La Selva in Costa.  When soil microarthropods (mites, springtails, coneheads etc) were excluded there is a difference between the temperate and tropical sites in the rate of litter breakdown, but no difference between the two tropical sites (upper panel).  In the lower panel the soil critters had access to the litter and a fairly pronounced difference emerged between the two tropical sites (expressing the influence of unique soil faunal assemblages on each site).