Abstract
● Nematode abundance and footprint show unimodal patterns with precipitation levels. ● MAP governed nematode diversity along the precipitation gradient of agroecosystem. ● Soil pH determined nematode abundance and footprint in low precipitation levels.
Precipitation plays a crucial role in global biodiversity change across terrestrial ecosystems. Precipitation is proven to affect soil organism diversity in natural ecosystems. However, how precipitation change affects the function of the soil nematode community remains unclear in cropland ecosystems. Here, we tested soil nematode communities from different precipitation sites (300 mm to 900 mm) of the agricultural ecosystem. The abundance of total nematodes, fungivores, and plant parasites, together with the footprint of fungivores was significantly affected by mean annual precipitation (MAP) in cropland ecosystem. Plant parasites diversity and footprint showed negative relationships with MAP. The random forest suggested plant parasite footprint was the most responsive to MAP. The structural equation model revealed that MAP affected nematode abundance and footprint indirectly via soil pH; nematode diversity was affected by MAP directly. We conclude that precipitation could act as the main selection stress for nematode diversity among the large gradient of agricultural ecosystems. However, the soil pH may act as a stress factor in determining nematode community and carbon flow in the soil food web. Our study emphasized that using nematode value by trophic group would provide a deep understanding of nematode response to precipitation in cropland ecosystems.