作者: Joan Elizabeth Damerow
DOI:
关键词: Historical ecology 、 Endemism 、 Ecology 、 Species richness 、 Habitat 、 Habitat destruction 、 Odonata 、 Geography 、 Species diversity 、 Generalist and specialist species
摘要: Climate and land-use change have altered continue to affect the diversity, composition, distribution of freshwater organisms throughout world. This is particularly true in arid semi-arid regions, where aquatic may experience more pronounced reductions available habitat with declines precipitation, increases water demand, degradation through human land-use. However, documentation changes taxonomic assemblages over long-time periods has been rare because difficulty obtaining historical occurrence data. dissertation used data from previously published literature, a resurvey study, museum specimens, enthusiast sightings document rates California past century.Summary information regarding taxa known occur did not exist central publication. I therefore conducted review several primary groups stream found Mediterranean region statewide. For this work, gathered variety literature sources specimens summarize species composition endemism region, identify gaps conservation priorities for examined groups. The remainder focuses largely on Odonata time California. charismatic group was ideal study their relatively low well-known taxonomy, existence sufficient current specimen records recent odonates.I sites originally sampled by Clarence H. Kennedy 1914-1915. work involved surveys odonates at 81 northwestern Nevada, 45 which were directly comparable Kennedy's original sites. that while site-level richness changed significantly, become homogeneous across Habitat generalists generally expanded extent specialists declined. In examining local regional factors influencing higher during site visits degree-days, especially highly mobile groups, including dragonflies migratory species. probability presence lower urban sites, specialists. Overall, both influenced implications conservation.A large component included development analysis database 33,000 century. museums odonate collections elsewhere, as well statewide years. noted these unstandardized contain biases regards uneven sampling effort, must be addressed analysis. Subsequent analyses before after 1975 indicated shifted northwards temperature warming minimum elevations response increased summer water-availability low-elevation agricultural regions. Similar results concluded combination biases, traits, climate detection last