Bioindicators of the Soil Food Web maturity structure
Bioindicators of the Soil Food Web • maturity • structure • function • resources • stress • recovery • management • assessment Howard Ferris Department of Nematology University of California, Davis hferris@ucdavis. edu
Soil food web structure - disturbance and recovery
Effects of minor disturbance
Effects of greater disturbance
Stress
Basal condition
Basal condition - what’s missing?
Effects of Enrichment
Recovery
Maturity
Structure
Evaluation of the Soil Food Web Structural Analysis u. Complete biotic analysis: sample, extract, identify, enumerate bacteria, fungi, protozoa, nematodes, arthropods, annelids, rodents……. . , etc. . u. Indicator guilds, faunal analysis Functional Analysis u. Rates of decomposition, mineralization, respiration, suppressiveness……. . , etc. .
Nematode Faunal Structure as a Soil Food Web Indicator Herbivores Bacterivores Fungivores Omnivores Predators
Why nematodes? • • • The most abundant of the metazoa Occupy key positions in soil food webs Standard extraction procedures Identification based on morphology Clear relationship between structure and function • Each sample has high intrinsic information value
Enrichment Indicators Rhabditidae Panagrolaimidae etc. ¨Short lifecycle ¨Small/ Mod. body size ¨High fecundity ¨Small eggs ¨Dauer stages ¨Wide amplitude ¨Opportunists ¨Disturbed conditions Structure Indicators Aporcelaimidae Nygolaimidae etc. Basal Fauna Cephalobidae Aphelenchidae, etc. ¨Moderate lifecycle ¨Small body size ¨Stress tolerant ¨Feeding adaptations ¨Present in all soils ¨Long lifecycle ¨Large body size ¨Low fecundity ¨Large eggs ¨Stress intolerant ¨Narrow amplitude ¨Undisturbed conditions
Nematode Guild Analysis Structured Basal h ric En B ed E M Ba 1 ric En 3. 2 cp-1 y tor c aje tr nt e hm Fu 2 0. 8 cp-2 Om 4 Om 5 3. 2 5. 0 Ca 2 Ca 3 Ca 4 Ca 5 0. 8 1. 8 3. 2 5. 0 Fu 2 Fu 3 Fu 4 Fu 5 0. 8 1. 8 3. 2 5. 0 Ba 2 Ba 3 Ba 4 Ba 5 0. 8 1. 8 3. 2 5. 0 cp-2 cp-3 cp-4 cp-5 Structure trajectory omnivores carnivores fungivores bacterivores
Testable Hypotheses of Foodweb Structure and Function Ba 1 Enriched • Maturing • N-enriched • Low C: N • Bacterial • Regulated En ric hm en t tr aje cto ry • Disturbed • N-enriched • Low C: N • Bacterial • Conducive Fu 2 Basal condition Ba 2 Structured Fu 2 • Degraded • Depleted • High C: N • Fungal Basal • Conducive Ca 3 Fu 3 Ba 3 Om 4 Ca 4 Fu 4 Ba 4 Structure trajectory Om 5 Ca 5 Fu 5 Ba 5 • Matured • Fertile • Mod. C: N • Bact. /Fungal • Suppressive
Basal Component: BI = 100 x S Guild(B) x Weight(B) / S Guild(B, ES) x Weight(B, ES) Enrichment Component: EI =100 x S Guild(E) x Weight(E) / S Guild(B, E. ) x Weight(B, E) Structure Component: SI = 100 x S Guild(S) x Weight(S) / S Guild(B, S) x Weight(B, S)
Annual System Averages
Annual crop agriculture Data from Ferris, et al
Annual crop agriculture
Perennial tree and vine crops
Forests
Stressed environments
Soil contamination Dmowska (1998) in De Goede and Bongers, Nematode communities of northern temperate grasslands
Soil contamination
Higher resolution
References Bongers, T. , M. Bongers. 1998. Functional diversity of nematodes. Applied Soil Ecology 10: 239 -251. Bongers, T. , H. Ferris. 1999. Nematode community structure as a bioindicator in environmental monitoring. Trends in Ecology and Evolution 14: 224 -228. Ferris, H. , T. Bongers, R. G. M. de Goede. 2001. A framework for soil food web diagnostics: extension of the nematode faunal analysis concept. Applied Soil Ecology 18: 3 -29. Ferris, H. and Bongers, T. 2009. Indices for analysis of nematode assemblages. Chapter 5 in: "Nematodes as Environmental Bioindicators". Editors: M. J. Wilson and T. Kakouli-Duarte. CAB International, Wallingford, UK, pp 124 -145. Ferris H. 2010. Form and function: metabolic footprints of nematodes in the soil food web. European Journal of Soil Biology 46: 97 -104. More information: http: //plpnemweb. ucdavis. edu/nemaplex
- Slides: 35