Dipodomys spectabilis: Ecosystem Engineers A look at Invertebrate Richness and Abundance By: Scott Johnson Mentor: Andrew Edelman

Dipodomys spectabilis Banner-tailed Kangaroo Rat Granivorous rodent Desert Grassland Ecosystem Ecosystem Engineers

Building Microhabitats Construct Mounds Earth slightly raised off the Ground Several entrances scattered across the mound Usually One K-rat per Mound

Supporting Evidence Thomas J. Valone, 1997 – Ant Correlation Hawkins and Nicolleto, 1992 – Mounds effect spatial organization of ground dwelling animals Shawn Whiteman, 2007 – Reptile Diversity (Whiteman 2007) Unoccupied

Research Questions How do mounds built by Dipodomys spectabilis influence invertebrate diversity? – Is overall richness and abundance at both occupied and unoccupied mounds higher than away from the mounds at the random grass sites? – Is overall richness and abundance at occupied mounds higher than unoccupied mounds?

Methods Set up pitfall traps to catch mainly terrestrial invertebrates 45 sites; 15 occupied mounds, 15 random sites, and 15 unoccupied mounds Random Sites set up at least 20m away Two pitfall traps at each site, totaling 90 traps, opposite each other at random directions Traps opened for five to six day periods Five total collections on 7-2, 7-9, 7-16, 7-23, 7-30 Traps open a total of 27 days

Occupied Random Unoccupied

Methods, cont. Two Solo Cups ¼ full with Propylene Glycol Pitfalls covered with ceramic tile to keep out debris and rain One meter plot around each trap measured for percent cover of grass, forbes, detritus, and bare ground Mound diameter measured and holes counted The invertebrates identified at the UNM arthropod museum by Dr. Brantley

Results Eleodes sp.ElateridaeScolopendra polymorpha Edrotes rotundusDasymutilla vestitaEremobates sp. SphecidaeVaejovis coahuilaeLycosidae Eleodes longicollisArenivaga erraticaMyrmeleontidae Ceuthophilus pallidusPsilochorus imitatusPasimachus sp. Psoloessa sp.Ophryastes globularisSphaeropthalma sp. Cicindela punctulataPompilidaeMelanastus sp. TyphoctinaeScutellaridaeAmphitornus coloradus Gryllus sp.TachinidaeEmblethis vicarious Cymatodera neomexicanaUnknown Fly 1 CicadellidaeEpicauta sp.Chloropidae NoctuidaeUnknown MothTachinidae LygaeidaeChrysopidaeAraeoschizus sp. Trombidium sp.Efferia sp.Dactylotum bicolor Reticulitermes tibialisPhyllophaga sp.Xanthippus corallipes Cremastocheilus sp.TingidaeOmorgus sp. Litaneutra minorNicrophorus guttulusTrimerotropis pallidipennis Melanoplus sp.Trachyrhinus marmoratus SyrphidaePhrynotettix robustusOrthoporus ornatus Latrodectus hesperusParabacillus coloradusTropidolophus formosus Helluomorphoides sp.Dasymutilla sp.Unknown Fly 2 All three typesOccupied onlyOccupied and UnoccupiedUnoccupied Only Unoccupied and RandomRandom OnlyOccupied and Random Invertebrate List

F = 3.2, P = 0.05 abb

F = 12.8, P < abb

t = 1.9, P = 0.06 ab aa

grassforbesdetritusbare ground a b c aaa aa b a bb

Discussion Statistically, Occupied mounds had significantly more diversity in average richness and average abundance than Unoccupied mounds or Random grass sites. Occupied and Unoccupied mounds were similar in size, but Occupied mounds had more openings. The type of vegetation cover over Occupied mounds differed from Unoccupied mounds and the Random Grass Sites.

Discussion How do mounds built by Dipodomys spectabilis influence invertebrate diversity? – Is overall richness and abundance at both occupied and unoccupied mounds higher than away from the mounds at the random grass sites? No. Richness and Abundance at Occupied mounds are significantly higher. Unoccupied mound diversity is similar to diversity at the Random site, though the components of the diversity differs. Unoccupied mound data tends toward an intermediate trend.

Discussion How do mounds built by Dipodomys spectabilis influence invertebrate diversity? – Is overall richness and abundance at occupied mounds higher than unoccupied mounds? YES.

Conclusion: The Why Dipodomys spectabilis altered their surroundings creating microhabitats for invertebrates. Microhabitat – Unique nutrient, water, and light levels – Soil disturbances on and near the mounds (Guo 1996) These microhabitats are important to the biodiversity of invertebrates in both abundance and richness

Acknowledgments University of New Mexico Sevilleta National Wildlife Refuge National Science Foundation US Fish and Wildlife Services Andrew Edelman Jennifer Johnson Dr. Scott Collins Dr. Sandra Brantley The UNM Arthropod Museum Shawn Whiteman Cathy McQueen Mike Friggens John DeWitt Andrew Rominger 2007 Sevilleta REUs 2007 Sevilleta Interns

References Best, Troy L (1988) Mammalian species dipodomys spectabilis. American Society of Mammologist 311:1-10 Guo, Qinfeng (1996) Effects of bannertail kangaroo rat mounds on small-scale plant community structure. Oecologia 106: Hawkins LK, Nicoletto PF (1992) Kangaroo rat burrows structure the spatial organization of ground-dwelling animals in a semi arid grassland. Arid Environment 20:199–208 Valone, Thomas J (1994) Interactions between rodents and ants in the chihuahuan desert: an update. Ecology 75: Whiteman, Shawn (2007) [enter thesis] Senior thesis