1960- 19thcentury congresses desertecology ecologicalsurveys ecology environmentalconditions environmentalmonitoring grasslandecology grasslandpeople greatplains history human-animalrelationships humanecology humangeography jeffreyalan juvenileliterature kansas lockwood management measurement naturalhistory nebraska northamerica plains prairieanimals prairieplants prairies sandhills spirituality unitedstates wetlands