Interactions between shrub encroachment and nitrogen addition on nematode community and functional traits on Qingzang Plateau

doi:10.17521/cjpe.2025.0119

Abstract

Abstract:

Aims Nematodes are a key component of belowground communities that maintain ecosystem structure and function. Global environmental changes, such as shrub encroachment and nitrogen deposition, have become key drivers of changes in belowground community structure and function. While multiple environmental factors may jointly influence biodiversity, the interactive effects of shrub encroachment and nitrogen deposition on soil nematode functional diversity remain poorly understood.

Methods In this study, we conducted a controlled experiment involving shrub removal and nitrogen addition on the eastern edge of Qingzang Plateau. We used the kernel density N-dimensional hypervolumes method to calculate nematode functional diversity and explore the response of nematodes to shrubs, nitrogen deposition, and their interactions.

Important findings Shrubs significantly increased nematode taxonomic diversity and altered their community composition, but these effects were less affected by nitrogen addition. Shrubs significantly increased nematode functional diversity, while nitrogen addition mitigated this positive effect. Shrubs altered the abundance proportion of nematodes with different diets, significantly increasing the proportion of herbivorous, bacterivorous, and fungivorous nematodes, but significantly decreasing the proportion of predatory nematodes. Moreover, nitrogen addition exacerbated the positive effects of shrub on lower trophic level nematodes and the negative effects on higher trophic level nematodes. Correlation and redundancy analysis (RDA) indicated that plant biomass and soil moisture were key factors driving nematode community composition and functional traits. Our findings suggest that under future nitrogen deposition and shrub encroachment, nematode functional diversity will become more homogenized.

Key words: soil nematode, functional diversity, functional trait, shrub effect, nitrogen addition, Qingzang Plateau

ZHANG An-Ning, XIAO Ya-Ning, ZHAO Xia, ZHANG Miao, CUI Han-Wen, CHEN Shu-Yan, AN Li-Zhe. Interactions between shrub encroachment and nitrogen addition on nematode community and functional traits on Qingzang Plateau[J]. Chin J Plant Ecol, 2026, 50(4): 859-869.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2025.0119

https://www.plant-ecology.com/EN/Y2026/V50/I4/859

Figures/Tables 9

References 30

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线虫属 Nematode	对照 Control		氮添加 Nitrogen addition		p
线虫属 Nematode	灌木存在 With shrub	灌木移除 Shrub removal	灌木存在 With shrub	灌木移除 Shrub removal	灌木效应 Shrub	氮效应 Nitrogen	交互作用 Shrub × nitrogen
拟丽突属 Acrobeloides	12.44 ± 3.69^a	23.43 ± 4.99^a	15.64 ± 4.16^a	2.40 ± 1.17^b	0.075	<0.001	<0.001
中杆属 Mesorhabditis	10.31 ± 4.30^ab	1.94 ± 1.16^b	10.94 ± 24.45^a	3.08 ± 1.82^ab	0.012	0.464	0.635
原矛属 Prodorylaimium	4.82 ± 2.28^b	1.82 ± 1.04^b	0.91 ± 0.53^b	15.21 ± 4.37^a	0.946	0.076	0.002
垫刃属 Tylenchus	7.95 ± 3.44^a	2.81 ± 1.68^a	9.27 ± 3.63^a	2.50 ± 1.36^a	0.167	0.864	0.746
真矛属 Eudorylaimus	3.47 ± 1.91^ab	0.84 ± 0.58^b	3.51 ± 1.92^ab	9.45 ± 4.45^a	0.034	<0.001	0.004
类滑刃属 Aphelenchoides	4.26 ± 2.87^a	4.30 ± 2.57^a	3.66 ± 2.31^a	1.58 ± 1.10^a	0.986	0.083	0.279
滑刃属 Aphelenchus	7.04 ± 1.86^a	0.46 ± 0.26^b	9.86 ± 2.21^a	0.22 ± 0.13^b	<0.001	0.258	0.138
盘旋属 Rotylenchus	8.72 ± 3.55^a	1.38 ± 0.82^b	2.98 ± 1.62^ab	2.57 ± 1.43^ab	0.002	0.318	0.045
单齿属 Mononchus	1.26 ± 0.76^b	1.27 ± 0.76^b	2.42 ± 1.35^ab	10.08 ± 3.73^a	0.998	<0.001	0.086
盆咽属 Panagrolaimus	2.77 ± 1.52^a	2.66 ± 1.36^a	1.80 ± 0.97^a	4.30 ± 2.21^a	0.937	0.341	0.246
异头叶属 Pseudacrobeles	5.80 ± 1.36^a	0.57 ± 0.29^b	7.61 ± 1.56^a	0.11 ± 0.07^c	<0.001	0.010	0.007
锉齿属 Mylonchulus	1.81 ± 1.16^a	5.50 ± 2.83^a	2.27 ± 1.25^a	2.36 ± 1.30^a	0.097	0.184	0.219
钵盘属 Mylodiscus	2.12 ± 1.19^ab	7.22 ± 2.95^a	1.13 ± 0.69^b	1.22 ± 0.73^b	0.035	0.003	0.167
大矛属 Enchodelus	0.33 ± 0.22^b	0.41 ± 0.28^b	0.41 ± 0.28^b	10.51 ± 3.12^a	0.733	<0.001	<0.001
绕线属 Plectus	5.01 ± 1.00^a	0.12 ± 0.07^b	6.42 ± 1.14^a	0.07 ± 0.04^b	<0.001	0.373	0.231

线虫属 Nematode	对照 Control		氮添加 Nitrogen addition		p
线虫属 Nematode	灌木存在 With shrub	灌木移除 Shrub removal	灌木存在 With shrub	灌木移除 Shrub removal	灌木效应 Shrub	氮效应 Nitrogen	交互作用 Shrub × nitrogen
拟丽突属 Acrobeloides	12.44 ± 3.69^a	23.43 ± 4.99^a	15.64 ± 4.16^a	2.40 ± 1.17^b	0.075	<0.001	<0.001
中杆属 Mesorhabditis	10.31 ± 4.30^ab	1.94 ± 1.16^b	10.94 ± 24.45^a	3.08 ± 1.82^ab	0.012	0.464	0.635
原矛属 Prodorylaimium	4.82 ± 2.28^b	1.82 ± 1.04^b	0.91 ± 0.53^b	15.21 ± 4.37^a	0.946	0.076	0.002
垫刃属 Tylenchus	7.95 ± 3.44^a	2.81 ± 1.68^a	9.27 ± 3.63^a	2.50 ± 1.36^a	0.167	0.864	0.746
真矛属 Eudorylaimus	3.47 ± 1.91^ab	0.84 ± 0.58^b	3.51 ± 1.92^ab	9.45 ± 4.45^a	0.034	<0.001	0.004
类滑刃属 Aphelenchoides	4.26 ± 2.87^a	4.30 ± 2.57^a	3.66 ± 2.31^a	1.58 ± 1.10^a	0.986	0.083	0.279
滑刃属 Aphelenchus	7.04 ± 1.86^a	0.46 ± 0.26^b	9.86 ± 2.21^a	0.22 ± 0.13^b	<0.001	0.258	0.138
盘旋属 Rotylenchus	8.72 ± 3.55^a	1.38 ± 0.82^b	2.98 ± 1.62^ab	2.57 ± 1.43^ab	0.002	0.318	0.045
单齿属 Mononchus	1.26 ± 0.76^b	1.27 ± 0.76^b	2.42 ± 1.35^ab	10.08 ± 3.73^a	0.998	<0.001	0.086
盆咽属 Panagrolaimus	2.77 ± 1.52^a	2.66 ± 1.36^a	1.80 ± 0.97^a	4.30 ± 2.21^a	0.937	0.341	0.246
异头叶属 Pseudacrobeles	5.80 ± 1.36^a	0.57 ± 0.29^b	7.61 ± 1.56^a	0.11 ± 0.07^c	<0.001	0.010	0.007
锉齿属 Mylonchulus	1.81 ± 1.16^a	5.50 ± 2.83^a	2.27 ± 1.25^a	2.36 ± 1.30^a	0.097	0.184	0.219
钵盘属 Mylodiscus	2.12 ± 1.19^ab	7.22 ± 2.95^a	1.13 ± 0.69^b	1.22 ± 0.73^b	0.035	0.003	0.167
大矛属 Enchodelus	0.33 ± 0.22^b	0.41 ± 0.28^b	0.41 ± 0.28^b	10.51 ± 3.12^a	0.733	<0.001	<0.001
绕线属 Plectus	5.01 ± 1.00^a	0.12 ± 0.07^b	6.42 ± 1.14^a	0.07 ± 0.04^b	<0.001	0.373	0.231

线虫指标 Nematode indicator	土壤 pH	电导率 Electrical conductivity	含水量 Soil moisture	土壤总磷含量 Total phosphorus content	土壤硝态氮含量 Ammonium nitrogen content	土壤铵态氮含量 Nitrate nitrogen content	植物生物量 Plant biomass	植物丰富度 Plant richness
物种多样性 Taxonomic diversity	-0.096	0.168	0.083	-0.535^*	0.043	0.025	-0.253	-0.032
功能多样性 Functional diversity	-0.001	0.090	0.184	-0.342	0.072	-0.145	-0.171	-0.020
C-P值 C-P value	0.139	-0.125	0.412	0.108	-0.498^*	0.089	0.350	0.275
线虫生物量 Biomass	0.233	0.195	0.554^*	-0.458^*	-0.394	0.060	-0.055	0.094
食细菌性占比 Bacterivore proportion	-0.068	0.199	-0.341	-0.044	0.462^*	-0.131	-0.301	-0.154
食真菌性占比 Fungivore proportion	-0.047	0.072	-0.175	-0.321	0.216	0.063	0.486^*	-0.356
植食性占比 Herbivore proportion	-0.136	0.136	-0.372	-0.134	0.168	0.013	-0.278	-0.227
杂食性占比 Omnivore proportion	-0.103	-0.170	0.165	0.091	-0.226	0.206	0.397	0.078
捕食性占比 Predator proportion	0.269	-0.191	0.546^*	0.224	-0.522^*	-0.076	0.415	0.427

线虫指标 Nematode indicator	土壤 pH	电导率 Electrical conductivity	含水量 Soil moisture	土壤总磷含量 Total phosphorus content	土壤硝态氮含量 Ammonium nitrogen content	土壤铵态氮含量 Nitrate nitrogen content	植物生物量 Plant biomass	植物丰富度 Plant richness
物种多样性 Taxonomic diversity	-0.096	0.168	0.083	-0.535^*	0.043	0.025	-0.253	-0.032
功能多样性 Functional diversity	-0.001	0.090	0.184	-0.342	0.072	-0.145	-0.171	-0.020
C-P值 C-P value	0.139	-0.125	0.412	0.108	-0.498^*	0.089	0.350	0.275
线虫生物量 Biomass	0.233	0.195	0.554^*	-0.458^*	-0.394	0.060	-0.055	0.094
食细菌性占比 Bacterivore proportion	-0.068	0.199	-0.341	-0.044	0.462^*	-0.131	-0.301	-0.154
食真菌性占比 Fungivore proportion	-0.047	0.072	-0.175	-0.321	0.216	0.063	0.486^*	-0.356
植食性占比 Herbivore proportion	-0.136	0.136	-0.372	-0.134	0.168	0.013	-0.278	-0.227
杂食性占比 Omnivore proportion	-0.103	-0.170	0.165	0.091	-0.226	0.206	0.397	0.078
捕食性占比 Predator proportion	0.269	-0.191	0.546^*	0.224	-0.522^*	-0.076	0.415	0.427

变量 Variable	df	F	p
土壤含水量 Soil moisture	1	2.505	0.010
植物生物量 Plant biomass	1	2.180	0.027
土壤总磷含量 Soil total phosphorus content	1	1.622	0.092
电导率 Electrical conductivity	1	1.211	0.247
土壤pH Soil pH	1	0.891	0.547
土壤硝态氮含量 Soil ammonium nitrogen content	1	1.313	0.191
土壤铵态氮含量 Soil nitrate nitrogen content	1	1.254	0.223
植物丰富度 Plant richness	1	0.838	0.581
残差 Residual	11