Nematode community responses to range‐expanding and native plant communities in original and new range soils

Abstract

Many plant species expand their range to higher latitudes in response to climate change. However, it is poorly understood how biotic interactions in the new range differ from interactions in the original range. Here, in a mesocosm experiment, we analyze nematode community responses in original and new range soils to plant communities with either (a) species native in both the original and new range, (b) range‐expanding species related to these natives (related range expanders), or (c) range expanders without native congeneric species in the new range (unrelated range expanders). We hypothesized that nematode community shifts between ranges are strongest for unrelated range expanders and minimal for plant species that are native in both ranges. As a part of these community shifts, we hypothesized that range expanders, but not natives, would accumulate fewer root‐feeding nematodes in their new range compared to their original range. Analyses of responses of nematodes from both original and new ranges and comparison between range expanders with and without close relatives have not been made before. Our study reveals that none of the plant communities experienced evident nematode community shifts between the original and new range. However, in soils from the new range, root‐feeding nematode communities of natives and related range expanders were more similar than in soils from the original range, whereas the nematode community of unrelated range expanders was distinct from the communities of natives and related range expanders in soils from both ranges. The abundances of root‐feeding nematodes were comparable between the original and new range for all plant communities. Unexpectedly, unrelated range expanders overall accumulated most root‐feeding nematodes, whereas related range expanders accumulated fewest. We conclude that nematode communities associated with native and range‐expanding plant species differ between the original and the new range, but that range‐expanding plant species do not accumulate fewer root‐feeding nematodes in their new than in their original range.

Nematodes as Drivers of Plant Performance in Natural Systems

“…Yet also generalist root-feeding nematodes may differently affect plant species they attack. First, fast-growing annual species may accumulate higher numbers of generalist rootfeeding nematodes than longer lived plant species, which typically invest more resources in defense [38], possibly explaining the contribution of nematodes to the turnover from ephemeral to more stable grassland communities [22] (Figure 2). Second, inoculation studies show that common generalist root-feeding nematodes, such as Meloidogyne hapla, significantly vary in their multiplication among grassland plant species, even when these are closely related [18,24,26,39].…”

“…Research on plant-nematode interactions of non-native plant species has also focused on the question as to whether decreases in root-feeding nematode diversity and abundance between the original and non-native range of alien plant species contribute to the increased performance of some non-native plants outside their native range (enemy release hypothesis) [84]. Indeed, some non-native plant species accumulate fewer root-feeding nematodes in their non-native range than in their native range, although these effects may be limited to (semi-) endoparasitic taxa and are only found for a couple of plant species [38,85,86]. Such reductions of root-feeding nematode numbers in the non-native range may be caused by the release from hostspecific taxa [86].…”

Latitudinal variation in soil nematode communities under climate warming‐related range‐expanding and native plants

“…Among soil biota, nematodes are the most abundant animals and perform key functions as bacterivores, fungivores, omnivores, predators and root herbivores (de Ruiter, Neutel, & Moore, 1995;Ferris, Bongers, & De Goede, 2001;Yeates, Bongers, Degoede, Freckman, & Georgieva, 1993), but their potential role in the success of rangeexpanding plant species is not yet fully understood (Morriën, Duyts, & van der Putten, 2012;Wilschut, Kostenko, Koorem, & van der Putten, 2018). Moreover, while root-feeding nematodes are well studied with respect to their role as agricultural pests (Nicol et al, 2011), their role in natural ecosystems has received less attention (De Deyn et al, 2003).…”

Range-expansion effects on the belowground plant microbiome

“…We targeted the microbiome of three plant groups: unrelated range-expanders - plant species without native species from the same genus in their new range; related range-expanders - plant species that have native species from the same genus in their new range (Supplementary Table 1 and Supplementary Figure 1); and native plant species, which are congeneric to the related range expanders and native throughout the entire gradient. All range expanding plants either arrived to or had greatly expanded within the Netherlands in the late 20 th and early 21 st centuries44. In an effort to minimize variation in abiotic factors, we selected 11 plant species grown on similar parent soil ( see methods).…”