Soil organic matter determines the distribution and abundance of nematodes on alluvial fans in Death Valley, California

Abstract

Death Valley, located within the Mojave Desert of the United States, is one of the most extreme terrestrial environments on Earth. We studied free‐living soil nematode abundance and community structure in soil samples collected from alluvial fans in Death Valley between 2013 and 2018. Our objective was to establish the distribution and abundance of soil nematodes on alluvial fans with respect to soil properties, vegetation, and channels that reflect past and future water flows. The study period spanned an extreme drought for the region but also included a 2016 superbloom of spring annual plants that followed a strong El Niño event. We found that nematode communities were dominated by bacterial‐feeding species and had higher densities under shrub canopies than in adjacent interplant soils. Nematode abundance was similar between areas on alluvial fans that were channelized by past water flows and adjacent desert pavement and does not appear to be linked to how water distributes on the fans following rainfall events. Nematode abundance increased during the superbloom in soils around annual plants. Across the study period, soil organic matter content was the only soil variable measured that was significantly and positively correlated to nematode abundance. Overall, nematodes in this extreme environment are adapted to drought, but they are highly dependent on the growth and distribution of both perennial and annual plants to supply the soil organic matter that their microbial food sources rely upon.

Efecto de la deposición de N y P atmosférico en la microfauna edáfica de sistemas de alta montaña de la red de Parques Nacionales

“…En general, y en concordancia con los resultados esperados, las abundancias de nematodos fueron más altas en los PPNN con una menor aridez y un mayor contenido de carbono orgánico en el suelo, con valores máximos en el PN Picos de Europa y mínimos en el PN del Teide, y valores intermedios en los PPNN de Guadarrama y Sierra Nevada. En todos ellos, el taxón más abundante fue Acrobeloides, un bacterívoro ubicuo resistente a las perturbaciones ambientales y común en numerosos tipos de ecosistemas (Hu et al 2015;Treonis et al 2019). En los tres PPNN peninsulares, los siguientes taxones más abundantes se correspondieron con organismos fungívoros, mientras que el herbívoro Gracilacus fue muy abundante en el PN del Teide, con unas abundancias muy variables.…”

Diversity of soil invertebrates in mixed grass communities adjacent to the Iska-Shor stream of Adak Nature Reserve, Komi Republic, Russia

“…Предположительно, ведущую роль в формировании их сообществ играют физико-химические свойства почвы, особенности растительного покрова, толерантность самих организмов к различным нарушениям. Полученные результаты подтверждают устойчивость нематод к воздействию всевозможных абиотических факторов: к низким и высоким температурам [Nicholas, 1984], недостатку влаги [Treonis et al, 2019], повышенной солёности и даже к токсическому действию тяжёлых металлов [Shih et al, 2019]. Коллемболы, напротив, чутко реагируют на изменения температуры и влажности почвы, непосредственно влияющие на их активность, плодовитость и смертность [Hopkin, 1997].…”

Using Nematode Community to Evaluate Banana Soil Food Web in Mekargalih, Cianjur, West Java

“…Sci. 44 (2): 465 -483 (2021) abundance has a negative correlation with soil moisture (Nielsen et al, 2014;Treonis et al, 2019). The abundance of the bacterivore and fungivore groups in Agr1 was higher than Agr2 and Agr3 (Table 3).…”

“…Soil organic matter (SOM) content correlated positively with the bacterivore and fungivore groups due to microbial activity (Treonis et al, 2019). Otherwise, Barros et al (2017) reported that SOM negatively correlated with herbivore groups.…”