Bird Use of Fields Treated Postharvest With Two Types of Flooding in Tulare Basin, California

作者：Fleskes Joseph P^*; Skalos Daniel A; Farinha Melissa A

来源：Journal of Fish and Wildlife Management, 2012, 3(1): 164-174.

DOI：10.3996/092011-JFWM-056

• agriculture
• California
• Central Valley
• density
• postharvest flooding
• Tulare Basin
• waterfowl

We surveyed birds on grain and nongrain fields in the Tulare Basin of California treated postharvest with two types of flooding that varied in duration and depth of water applied (flooded-type [FLD] fields: <1 cm-1.5 m for >1 wk; irrigated-type [IRG] fields: <1-15 cm water for <1 wk at a time). Our goal was to compare use of these field types by birds to guide habitat conservation in the region. During 19 August-6 December 2005, we counted a total of 80,316 birds during 23 surveys of 5 FLD fields (four wheat, one alfalfa) and 8,225 birds during 38 surveys of 33 IRG fields (23 cotton, 4 tomato, 3 wheat, 1 alfalfa, 1 oat, 1 fallow). We recorded 14 waterfowl (13 duck, 1 goose), 29 other waterbird (coots, shorebirds, grebes, pelicans, herons, egrets, gulls, terns), and 14 nonwaterbird (passerines, raptors, and vultures) species on FLD fields compared to 5 duck, 14 other waterbird, and 9 nonwaterbird species on IRG fields. Species composition differed by field type; waterfowl comprised a greater percentage (FLD vs. IRG, 16.2% vs. 1.3%), other waterbirds a similar percentage (80.4% vs. 71.6%), and nonwaterbirds a lower percentage (3.5% vs. 27.1%) of birds on FLD than on IRG fields. The modeled density estimate of waterfowl was 108 times greater on FLD than IRG fields and 7.4 times greater on grain than nongrain fields. The density estimate of other waterbirds was 11.8 times greater on FLD than IRG fields and 4.4 times greater on grain than nongrain fields. The density estimate of nonwaterbirds was 14.3 times greater on grain than nongrain fields but did not differ by flood type. Long duration (i.e., >1 wk) flooding increased waterbird use of grain fields in the Tulare Basin more than in the northern Central Valley. Thus, even though water costs are high in the Tulare Basin, if net benefit to waterbirds is considered, management programs that increase availability of FLD fields (especially grain) in the Tulare Basin may be a cost-effective option to help meet waterbird habitat conservation goals in the Central Valley of California.

• 出版日期2012-6