Patterns of Pseudacris sierra Abundances within a Commercial Rice Ecosystem: Advancing Sustainable Rice Solutions

Abstract

Ecosystem services (ES) are the natural services provided by organisms and ecosystems that benefit humanity and have been proposed as a strategy to more sustainably produce agricultural goods by reducing the externalized environmental costs of agricultural production. Identifying how specific cultivation practices affect species that inhabit agricultural ecosystems has the potential to establish modified agricultural practices that promote ES. Rice fields are dynamic agricultural ecosystems that can support a high degree of biodiversity and can serve as critical wetland habitats for a diversity of species, including anuran amphibians. We sought to determine how conventional and organic rice cultivation practices within the Central Valley of California influence anuran populations among commercially operating farms. In addition, we tested whether behavioral mechanisms could possibly be shaping abundance patterns between types of rice cultivation. The Sierran treefrog (Pseudacris sierra) was the most common anuran detected among surveyed California rice fields, and there were significantly more P. sierra detected in organic relative to conventional rice fields. Interestingly, P. sierra abundances varied across individual fields, possibly because of adjacent field effects, vegetation heterogeneity, or behavioral factors. In a dichotomous choice test, we observed that male frogs spent more time on substrate soaked with water sourced from organic fields, while females were indifferent, suggesting that male P. sierra may be actively seeking organic rice fields for reproduction. These findings may be used as the initial steps to develop strategies that promote anurans and their intrinsic ES within rice agricultural ecosystems, advancing sustainable rice cultivation.