Comparison of Epigeal Beetle Assemblages in

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Comparison of Epigeal Beetle Assemblages
in Remnant and Restored Riparian Forests on the
Middle Sacramento River, California ____ John
W. Hunt USDA Natural Resource Conservation
Service Scott Chamberlain Rice
University David M. Wood CSU, Chico
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• Sampling terrestrial arthropod communities Why?
• Abundant species-rich component of most
  terrestrial habitats
• Sensitive and useful indicators of habitat
  change
• Effects of anthropogenic disturbance poorly
  documented
• Threatened by gt two invasive invertebrate pests
• Argentine ant (Linepithema humile)
• Imported red fire ant (Solenopsis invicta)

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• Sampling of epigeal beetles (Order Coleoptera)
• Manageable component of arthropod diversity
• Taxonomy relatively well known
• Forest floor occurs in all forest types
• Methods widely used and reviewed
• Goals
• Examine community arthropod composition
• Examine utility/feasibility of methodology
  taxa

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• Specific Objectives
• Test for difference amongst forest types for
• Sample assemblages at the order and family level
• Seasonal change in community composition
• Intraspecific abundances Indicator Species
• Examine utility of morphospecies approach
• Implement monitoring of riparian arthropod
  assemblages

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• Study Sites
• Nine sample sites
• Distributed over 70 river miles
• Four geographic locations
• Stratified into 3 treatment types (3 replicates
  each)
• Young restoration sites 2 - 3 years old
• Old restoration sites 6 - 11 years old
• Remnant riparian forest sites gt 30 years old

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Pitfall trap design

• Pitfall trap (left) and transect layout (right)
• Traps opened simultaneously at all sites
  1-week/month for 1-year
• Traps closed between sampling periods

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Sample sorting

• Individuals separated and labeled by
• Date
• Site
• Trap position
• Morphospecies given alphanumeric pseudonym (i.e.
  A1, A2, etc.).
• Individuals pinned or stored in ethanol

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Sample sorting

• Taxonomy determined to lowest level practicable
• Reference texts
• Visiting collections
• Help from other biologists (e.g. Dr. Kirby
  Brown and Scott Chamberlain)
• All data entered into relational database

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• Focal taxa
• Taxa stratified into 3 taxonomic hierarchies for
  analysis
• Order-level (Coleoptera)
• Family-level 3 most abundant and species rich
  families
• Carabidae (ground beetles)
• Staphylinidae (rove beetles)
• Tenebrionidae (darkling beetles)
• Species-level

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Carabidae (Ground beetles)
Calosoma cancellatum Eschscholtz
Pterostichus lustrans, Le Conte

• Typical taxon for pitfall sampling - abundance
  of epigeal species
• Taxonomy relatively well worked out
• Polyphagous primarily scavengers and predators
• Morphology - generally uniform dull colors
  (some iridescent), margined pronotum, and striate
  elytra

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• Staphylinidae (Rove beetles)

Dinothenarus sp.
Subtribe Medonina

• Most species rich family of beetles in North
  America
• Taxonomy and classification exceedingly
  difficult
• Often recognized by elongate bodies and truncate
  elytra

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Tenebrionidae (Darkling beetles)
N. aequicollis
Nyctoporus sponsa
Eleodes dentipes

• Slow-moving, flightless, dark colored, armored,
  antennae attach beneath frontal ridge
• Herbivores, granivores, fungivores and/or
  detritivores.
• Associated with trees and dead wood of
  forests-savannahs or soils in habitats ranging
  from forests to deserts (Aalbu et. al 2001)

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• Order- and Family-level Analyses
• Morphospecies trap totals were
• Standardized - converted to of sample unit
  total
• Arcsine square-root transformed - to reduce
  influence of abundant and rare species
• Cluster analysis performed with group-average
  linking of Bray-Curtis dissimalarities
• Site ordination performed with Nonmetric
  Multidimensional Scaling (NMS)

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• Order- and Family-level Analyses
• NMS Ordinations
• Stress values (0-100) give the reliability of
  the ordination
• lt10 is good
• Monte Carlo test gives probability of that value
  obtained by chance
• Ranked Multi-Response Permutation Procedure
  (MRPP) test of Bray Curtis matrix values to test
  for effect of forest type

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• Statistical Analyses
• Species-level Analyses
• ANOVA or Kruskal-Wallis test for effect of
  forest type on mean monthly abundance
• Tukey (ANOVA) or a Nemenyi test (K-W) pair-wise
  comparisons

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• Results
• Sampling was conducted over the course of one
  calendar year.
• 24,626 individual beetles sorted
• 188 morphospecies
• 87 morphospecies trapped only once
• 25 trapped only twice.

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MRPP A 0.24 p 0.002)
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SV 3.498 Monte Carlo p 0.03 r-value axis 1
0.507, axis 2 0.375)
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SV 12 Monte Carlo p 0.01 r-value axis 1
0.58, axis 2 0.30
MRPP A 0.14 p lt 0.001)
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MRPP A 0.27 p 0.001)
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SV 5.6 Monte Carlo p 0.03 r-value axis 1
0.78, axis 2 0.11
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MRPP A 0.24 p 0.001)
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MRPP A 0.43 p 0.01)
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SV 0.001 Monte Carlo plt0.02 r-value axis 1
0.323, axis 2 0.574
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• Discussion Order-level analysis
• MRPP showed significant effect of forest age
  class at order- and family- level
• Sites generally grouped by age class
• RR sites most similar to one another suggesting
  higher relative stability
• YR site assemblages exhibited highest variation
• Older sites may share stabilizing habitat
  characteristics
• NMS ordination indicates trajectory of
  assemblages based on forest age

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• Discussion Family-level analyses
• Carabidae
• Most species-rich family sampled
• Clear assemblage response to forest age
• Staphylinidae
• Cluster analysis portrayed effect of forest age
• Ordination results poor and ambiguous.
• Tenebrionidae
• Relatively few species sampled
• Cluster analysis indicates grouping by forest
  age
• Forest age classes overlapped in ordination

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• Discussion Species-level analyses
• ANOVA and K-W
• Significant effect of forest type on 37
  morphospecies in 13 families
• 14 morphospecies - OR and RR sites gt YR
• 16 morphospecies - YR sites gt OR and RR
• 7 morphospecies - OR sites gt YR and RR

Eulabis bicarinata Eschscholtz
Bisnius sp.
Poecilus occidentalis Dejean
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• Discussion -Other patterns
• Some species had narrow geographic distributions
  and showed a significant effect of forest type
• Nyctoporis sponsa (Tenebrionidae) Trapped only
  at PH (RR)
• N. aequicollis (Tenebrionidae) Trapped only at
  RV (RR)
• Some species showed strong seasonal abundances
  pattern
• Calosoma cancellatum (Carabidae) trapped from
  Apr - August
• Eleodes dentipes (Tenebrionidae) - trapped from
  May - July

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• Conclusion
• Riparian restoration creating habitat for many
  riparian forest invertebrates
• Features associated with an increase in forest
  age
• Canopy closure and deciduous litter
• Woody debris (Tenebrionidae)
• Decrease in soil bulk density
• Development of forest interior can buffer
• Wind
• Temperature/radiation

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Acknowledgments Kirby Brown - Entomologist
Kristina Schierenbeck CSU, Chico Tom Griggs
River Partners Don Miller CSU, Chico Joe
Silveira - USFWS Greg Golet TNC Eric Hohenstein
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The End