Tigar, Barbara Jane; (1998) The abundance and diversity of desert invertebrates in Abu Dhabi and their role in the diet of the houbara bustard Chlamydotis undulata macqueeni. Doctoral thesis (Ph.D), UCL (University College London).

Text The_abundance_and_diversity_of.pdf Download (15MB)

Abstract

Invertebrate abundance and diversity were monitored for two years at five sites in Abu Dhabi, and houbara bustard faecal and gizzard contents were examined to establish the role of invertebrates in the diet. Literature on houbara diet was used to calculate a relative citation index for known foods. Invertebrates, particularly Coleoptera, Orthoptera and Formicidae, scored highest; Tenebrionidae were especially important. All houbara subspecies ate plants from the families: Gramineae, Leguminosae, Cruciferae, Compositae and Solanaceae. African and Arabian houbara also ate Zygophyllaceae and Chenopodiaceae. Canary Island birds may have a narrower diet than mainland houbara. Overnight pitfall and light-traps captured 143,397 invertebrates, including 196 new records and ten new species. Pitfalls frequently contained: Formicidae (75.4%), Thysanura (12%), Coleoptera (8.4%), Araneae (1.5%) and Scorpiones (1.1%). Light traps had high catches of Lepidoptera (56.4%) and Coleoptera (19.1%); Coleoptera contributed the highest biomass (42.6%). Fewer invertebrates were caught in winter than in summer, and catches were positively correlated with temperature. There were significant differences in community composition between sites and substrates. Isoptera, Tettigoniidae and Carabidae were rarely captured inland, but more taxa occurred near the coast. Pitfalls captured higher numbers of more diverse predaceous arthropods at new moons than at full moons, suggesting differences in invertebrate predation risk or visual awareness of traps. Similar food remains were recovered from houbara faeces and gizzards. Trials established a calibration for the recovery of prey remains in faeces. Formicidae were the most frequently consumed prey, but Tenebrionidae formed the highest biomass. Plants made a low but frequent contribution to the diet. Estimated Active Metabolic Rate suggested that invertebrates contributed 89-94.6% to houbara energy needs, and the frequency of invertebrates in faeces showed good rank agreement with pitfall catches. Desert invertebrates showed spatial and temporal variation and over-wintering houbara appeared to be non-selective, consuming mainly locally available, ground- dwelling invertebrates.

Download activity - last month

Export as JSONCSVXML

Download activity - last 12 months

Export as XMLCSVJSON

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item