scholarly journals Bottom-up effects on arthropod communities in Platycyamus regnellii (Fabaceae) fertilized with dehydrated sewage sludge

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Gezilene Fernandes de Souza ◽  
Germano Leão Demolin Leite ◽  
Farley William Souza Silva ◽  
Regynaldo Arruda Sampaio ◽  
Júlia Letícia Silva ◽  
...  

Sewage sludge is a nitrogen-rich organic compound, which can be used to aid development in plants such as Platycyamus regnellii (Fabaceae), in the recovery of degraded areas. This study aimed to assess the bottom-up effects on leaf mass and percentage ofground cover (leaf litter, herbaceous plants, and grasses) in P. regnellii trees fertilized (or not) with dehydrated sewage sludge and arthropod communities over 24 months. Platycyamus regnellii trees fertilized with dehydrated sewage sludge presented significantly more leavesper branch, branches per tree, and a higher percentage of ground cover compared to unfertilized trees. Phenacoccus sp. (Pseudococcidae) was the most abundant phytophagous insect associated with P. regnellii trees. Fertilization did not affect the abundance, diversity, and species richness of Hemiptera phytophagous on P. regnellii trees. However, fertilizedtrees presented higher abundance and species richness of trophobiont-tending ants compared to unfertilized trees, with Camponotus sp. being the most abundant regardless of the treatment. Fertilized P. regnellii trees also presented higher species richness of natural enemies compared to unfertilized ones, with Aranae and Dolichopodidae being the most abundant. We concluded that fertilization with dehydrated sewage sludge improved P. regnellii trees leafmass and ground cover and increased the diversity of trophobiont-tending ants and natural enemies. To our knowledge, this is the first study on the arthropods community associated withthis tree species. This suggests that upon fertilization, P. renellii trees are useful for ecological restoration in severely disturbed areas.

Author(s):  
Huan Zhao ◽  
Jiahuan Li ◽  
Lizhu Guo ◽  
Kun Wang

The expansion of agriculture and intensive mechanized production have resulted in the loss of habitats and biodiversity, which has led to the loss of ecological services such as the biological control of pests and diseases, and insect-borne pollination. Current studies mainly focus on the impact of small-scale crop diversity (such as intercropping) on ecological service but lack research on the effects of crop diversity at the landscape scale. In this study, vegetation-dwelling arthropods in naked oat (Avena chinensis) fields under different planting patterns were collected at different growth stages by standardized sweep netting sampling, and the differences in arthropod communities and temporal dynamics were analyzed. Taking this information as an example, the effects of crop diversity at the landscape scale caused by different planting patterns on arthropod communities were studied. It was found that herbivores were the most abundant functional group in the arthropod community in naked oat fields, accounting for 70.13% of the total abundance, followed by natural enemies, accounting for 23.45%, and, finally, other insects. The abundance and species richness of natural enemies in naked oat fields under diversified planting pattern were significantly higher than those under intensive planting pattern, while the abundance and species richness of herbivorous pests showed no significant difference between the two planting patterns. Planting patterns significantly affected the composition and structure of arthropod communities in naked oat fields. Significantly higher ratio of natural enemy to pest and more diverse natural enemies under the diversified planting pattern have shown better biological control potential and the significance of biodiversity protection.


2011 ◽  
Vol 59 (2) ◽  
pp. 158-170 ◽  
Author(s):  
E. Aguilar-Fenollosa ◽  
M.V. Ibáñez-Gual ◽  
S. Pascual-Ruiz ◽  
M. Hurtado ◽  
J.A. Jacas

1992 ◽  
Vol 70 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Gisela Cuenca ◽  
Milagros Lovera

Savannas growing on stony, old and nutrient-poor soils of southern Venezuela were severely disturbed by removal of the soil organic layers with bulldozers for road building. Introduced species Brachiaria decumbens, Brachiaria humidicola, Pueraria phaseoloides, and Calopogonium sp. were sown. The substrate was fertilized and limed. Plant cover, vesicular – arbuscular mycorrhizae colonization, spore number, and most probable number of propagulels in undisturbed savanna, disturbed nonrevegetated savanna, and six revegetated savannas were assessed. The perturbation reduced the mycorrhizal propagule number in comparison with the undisturbed savanna. In the nonrevegetated areas the mean percent ground cover 2 years after disturbance was low (0.04%). In revegetated areas an increase in mycorrhizal propagule number occurred and the mycorrhizal colonization of the sown species was high. In restored areas there was an increase in species of nonmycotrophic Amaranthaceae. The results support other predictions on the mycorrhizae in successional biomes, because in the extremely nutrient-poor soils studied the colonizing species were mainly mycotrophic. The reclamation program applied in disturbed areas was useful because it has allowed the recovery of vesicular – arbuscular mycorrhizal inoculum and there was an increase in the recolonization of native plants. Key words: disturbance, endomycorrhizae, revegetation, savanna, vesicular – arbuscular mycorrhizae.


2021 ◽  
Author(s):  
Malte Jochum ◽  
Lise Thouvenot ◽  
Olga Ferlian ◽  
Romy Zeiss ◽  
Bernhard Klarner ◽  
...  

AbstractDeclining arthropod communities have recently gained a lot of attention with climate and land-use change among the most-frequently discussed drivers. Here, we focus on a seemingly underrepresented driver of arthropod-community decline: biological invasions. For ∼12,000 years, earthworms have been absent from wide parts of northern North America, but they have been re-introduced with dramatic consequences. Most studies investigating earthworm-invasion impacts focus on the belowground world, resulting in limited knowledge on aboveground-community changes. We present observational data on earthworm, plant, and aboveground-arthropod communities in 60 plots, distributed across areas with increasing invasion status (low, medium, high) in a Canadian forest. We analyzed how earthworm-invasion status and biomass impact aboveground arthropod community abundance, biomass, and species richness, and how earthworm impacts cascade across trophic levels. We sampled ∼13,000 arthropods, dominated by Hemiptera, Diptera, Araneae, Thysanoptera, and Hymenoptera. Total arthropod abundance, biomass, and species richness declined significantly from areas of low to those with high invasion status with reductions of 61, 27, and 18%, respectively. Structural Equation Models unraveled that earthworms directly and indirectly impact arthropods across trophic levels. We show that earthworm invasion can alter aboveground multitrophic arthropod communities and suggest that belowground invasions can be important drivers of aboveground-arthropod decline.


2021 ◽  
Author(s):  
Li-Lin Chen ◽  
Gabor Pozsgai ◽  
Xiang-Yu Li ◽  
Lei Li ◽  
Gadi V.P. Reddy ◽  
...  

AbstractBeetles are visible members of food webs in tea plantations, with high species richness and abundance. Many tea pests, as well as natural enemies, are members of this order, so a knowledge of how groundcovers affect beetles can aid pest management. We collected beetles in a replicated field experiment in the Wuyi Mountains, Fujian Province China. Tea was intercropped with Paspalum notatum or Chamaecrista rotundifolia, or rows were cleared to bare ground, or in the control they were left unmanaged to allow weeds to grow naturally. Sampling, done by sweep netting and vegetation beating, was conducted monthly, between May 2006 and April 2008, and Coleoptera abundance, biomass, species richness and assemblage structures were compared between groundcover treatments. Total beetle abundance and species richness were significantly higher in tea intercropped with C. rotundifolia and bare ground than in naturally grown weedy control. Whilst there was no difference between predator assemblages among treatments for any measure, herbivores were more abundant, weighed more, and were more diverse in C. rotundifolia treatments than in weedy control. Biomass and species richness were also greater in plots with P. notatum groundcover than those in weedy control. We found that beetle assemblages varied both seasonally and with ground cover treatment, but the potential pest control impact of more species-rich beetle assemblages was mixed, and further work is needed to gain information on trophic groups with potential benefits for use in non-insecticidal pest management.


PLoS ONE ◽  
2020 ◽  
Vol 15 (8) ◽  
pp. e0237261
Author(s):  
Luan Rocha Dourado ◽  
Germano Leão Demolin-Leite ◽  
Marcus Alvarenga Soares ◽  
Gustavo Leal Teixeira ◽  
Farley William Souza Silva ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jó Cássio Nascimento Carvalho ◽  
Farley William Souza Silva ◽  
Germano Leão Demolin Leite ◽  
Alcinei Mistico Azevedo ◽  
Gustavo Leal Teixeira ◽  
...  

2020 ◽  
Vol 6 (4) ◽  
pp. 243-259 ◽  
Author(s):  
Michael Staab ◽  
Andreas Schuldt

Abstract Purpose of Review Natural enemies are an important component for forest functioning. By consuming herbivores, they can be effective top-down regulators of potential pest species. Tree mixtures are generally expected to have larger predator and parasitoid populations compared to monocultures. This assumption is based on the “enemies” hypothesis, a classical ecological concept predicting a positive relationship between plant diversity (and complexity) and natural enemies, which, in turn, should increase top-down control in more diverse environments. However, the “enemies” hypothesis has mostly been tested and supported in relatively simple agricultural ecosystems. Until recently, research in forests was sparse. We summarize the upcoming knowledge-base for forests and identify forest characteristics likely shaping relationships between tree diversity, natural enemies (abundance, species richness, diversity), and top-down control. We further identify possible implications for mixed species forestry and key knowledge gaps. Recent Findings Tree diversity (almost exclusively quantified as tree species richness) does not consistently increase enemy abundance, diversity, or result in herbivore control. Tests of the “enemies” hypothesis are largely based on aboveground natural enemies (mainly generalists) and have highly variable outcomes across taxa and study systems, sometimes even finding a decrease in predator diversity with increasing tree diversity. Recurrent effects of tree species identity and composition indicate that a closer focus on tree functional and phylogenetic diversity might help to foster a mechanistic understanding of the specific circumstances under which tree diversity can promote top-down control. Summary Our review suggests that the “enemies” hypothesis may not unambiguously apply to forests. With trees as structurally complex organisms, even low-diversity forests can maintain a high degree of habitat heterogeneity and may provide niches for many predator and parasitoid species, possibly blurring correlations between tree and natural enemy diversity. Several further factors, such as latitude, identity effects, intraguild predation, or functional and phylogenetic components of biodiversity, may confound the predictions of the “enemies” hypothesis. We identify topics needing more research to fully understand under which conditions tree diversity increases natural enemy diversity and top-down control—knowledge that will be crucial for forest management.


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