Faunal Perturbation Effect on Soil Biodiversity-Desert Ecosystems
Investigators (most current known information)
Proposal Abstract
This project compared soil properties and soil biota associated with seed harvesting ant colonies and badger mounds in the Negev Desert, Israel and soil properties, soil biota, and vegetation associated with temporally persistent ant colonies in the Chihuahuan Desert in New Mexico. There is a substantial literature on the effects of seed harvesting ants on arid ecosystems that has failed to provide a conceptual framework for those effects and/or a conceptual model for predicting the effects of ant colonies on soil properties and processes in different topographic positions on landscapes. There are also no conceptual models that incorporate temporal variation in soil biota and how temporal (seasonal) changes may influence the impacts of ants on the soil. Our studies provide data on spatial scales ranging from watersheds to small catenas and temporal scales of several seasons. These data provide a framework for a conceptual model of the effects of species of ants that build nests that persist for more than a decade, on soil properties, soil biota, vegetation, and soil processes.
The Chihuahuan Desert studies focused on nests of (1) a seed harvesting ant, Pogonomyrmex rugosus, (2) nests of a generalist forager, Aphaenogaster cockerelli, and (3) nests of a liquid-feeding honey-pot ant, Myrmecocystus depilis. The nests of these three species persist for more than a decade and all of these species have an effect on soil biota and the species richness, density, cover or biomass of vegetation associated with the nests in comparison to reference sites. These data demonstrate that the effects of ants on soil and soil biota is not a function of the behavior of seed harvesting and accumulation of seed waste around the nests but is a function of the length of time that nests are occupied by ants independent of their trophic status. However the direction of the differences in soil biota and vegetation is not the same for the same ant species in different locations on a catena or different locations on a watershed (Draft Manuscript – Appendix 1). For example, different protozoan morphotypes were more abundant in reference soils associated with P. rugosus nests in one location but more abundant in nest soils in another location {Draft Manuscript – Appendix 2). The studies in the Negev document the effects of seed harvesting ants and the effects of persistent mounds created by the digging activity of porcupines. The Negev studies also document the differences in soil biota associated with topographic position on a watershed and seasonal effects of antecedent rainfall.
Most of the data has been analyzed and manuscripts (which are at different stage) had been prepared. Therefore the detailed analysis and drafts of manuscripts are included here as the bulk of this final report. The draft manuscripts included in the final report are:
- Effect of Temporally Persistent Ant Nests on Soil Protozoan Communities and the Abundance of Morphological Types of Amoebae
- Effect of Ants on Abundance and Structure of Soil Free-living Nematode Communities in an Arid Ecosystem
- Effects of the Nests of Three Species of Chihuahuan Desert Ants on Soil Properties and Spring Annual Plants
- Faunalpedturbation Effects on Soil Microarthropod Population Dynamics in the Negev Desert
- Effects of the Persistent Nests of Chihuahuan Desert Ants on Soil Microbial Community
- Faunalpedturbation Effects on Soil Free-living Nematode Populations in the Negev Desert
Outcome
No outcomes reported