The effect of shrub clearing and grazing on the composition of a Mediterranean plant community: functional groups versus species

1999 ◽  
Vol 10 (5) ◽  
pp. 673-682 ◽  
Author(s):  
Liat Hadar ◽  
Imanuel Noy‐Meir ◽  
Avi Perevolotsky
2021 ◽  
Vol 162 ◽  
pp. 106179
Author(s):  
Zhiying Ning ◽  
Xueyong Zhao ◽  
Yulin Li ◽  
Lilong Wang ◽  
Jie Lian ◽  
...  

2015 ◽  
Vol 23 (6) ◽  
pp. 760-767 ◽  
Author(s):  
Joaquim S. Silva ◽  
Filipe X. Catry ◽  
Francisco Moreira ◽  
Miguel N. Bugalho

2021 ◽  
Vol 12 ◽  
Author(s):  
Lise Thouvenot ◽  
Olga Ferlian ◽  
Rémy Beugnon ◽  
Tom Künne ◽  
Alfred Lochner ◽  
...  

As ecosystem engineers, invasive earthworms are one of the main drivers of plant community changes in North American forests previously devoid of earthworms. One explanation for these community changes is the effects of earthworms on the reproduction, recruitment, and development of plant species. However, few studies have investigated functional trait responses of native plants to earthworm invasion to explain the mechanisms underlying community changes. In a mesocosm (Ecotron) experiment, we set up a plant community composed of two herb and two grass species commonly found in northern North American forests under two earthworm treatments (presence vs. absence). We measured earthworm effects on above- and belowground plant biomass and functional traits after 3 months of experiment. Our results showed that earthworm presence did not significantly affect plant community biomass and cover. Furthermore, only four out of the fifteen above- and belowground traits measured were affected by earthworm presence. While some traits, such as the production of ramets, the carbon and nitrogen content of leaves, responded similarly between and within functional groups in the presence or absence of earthworms, we observed opposite responses for other traits, such as height, specific leaf area, and root length within some functional groups in the presence of earthworms. Plant trait responses were thus species-specific, although the two grass species showed a more pronounced response to earthworm presence with changes in their leaf traits than herb species. Overall, earthworms affected some functional traits related to resource uptake abilities of plants and thus could change plant competition outcomes over time, which could be an explanation of plant community changes observed in invaded ecosystems.


2002 ◽  
Vol 82 (4) ◽  
pp. 403-411 ◽  
Author(s):  
A. Faz Cano ◽  
A R Mermut ◽  
R. Ortiz ◽  
M B Benke ◽  
B. Chatson

Soils in southern Spain are low in organic matter (OM) and nutrients. Understanding the nature and dynamics of OM has potential to improve soil management technologies for sustainable crop production. The objective of this work was to establish the distribution of functional groups in organic-C from these soils using 13C CP/MAS-NMR spectroscopy and to investigate the influence of vegetation, climatic conditions, soil parameters, parent material, and soil order on these functional groups. No statistically significant variability in the distribution of organic-C groups was found as a result of the influence of either soil order or parent material. The content of O-alkyl-C in the soils under the Rhamno-Quercetum plant community was higher (95% probability) than in the soils under the Paronychio-Sideritidetum plant community. Soils located in the mesomediterranean climatic zone displayed a higher content of O-alkyl-C and a lower content of aromatic-C compared to the soils located in the thermomediterranean zone. These differences were statistically significant at 95% of probability. Vegetation and climatic conditions appear to play a major role in the OM decomposition processes in this region. Statistically significant and positive correlations were found between alkyl-C and both cation exchange capacity (CEC) and clay content indicating the recalcitrant nature of these organic compounds. Key words: Organic matter composition, Spanish soils, 13C CP/MAS-NMR spectra, Mediterranean soils, Alfisols, Mollisols, Aridisols


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1432
Author(s):  
Alon Ornai ◽  
Tamar Keasar

Despite intensive research, predicting pairwise species associations in pollination networks remains a challenge. The morphological fit between flowers and pollinators acts as a filter that allows only some species within the network to interact. Previous studies emphasized the depth of floral tubes as a key shape trait that explains the composition of their animal visitors. Yet, additional shape-related parameters, related to the handling difficulty of flowers, may be important as well. We analyzed a dataset of 2288 visits by six bee genera to 53 flowering species in a Mediterranean plant community. We characterized the plant species by five discrete shape parameters, which potentially affect their accessibility to insects: floral shape class, tube depth, symmetry, corolla segmentation and type of reproductive unit. We then trained a random forest machine-learning model to predict visitor identities, based on the shape traits. The model’s predictor variables also included the Julian date on which each bee visit was observed and the year of observation, as proxies for within- and between-season variation in flower and bee abundance. The model attained a classification accuracy of 0.86 (AUC = 0.96). Using only shape parameters as predictors reduced its classification accuracy to 0.76 (AUC = 0.86), while using only the date and year variables resulted in a prediction accuracy of 0.69 (AUC = 0.80). Among the shape-related variables considered, flower shape class was the most important predictor of visitor identity in a logistic regression model. Our study demonstrates the power of machine-learning algorithms for understanding pollination interactions in a species-rich plant community, based on multiple features of flower morphology.


2021 ◽  
Author(s):  
Kamrul Hassan ◽  
Yolima Carrillo ◽  
Uffe N. Nielsen

Abstract Background Climate changes can shift plant-soil feedbacks (PSFs) causing unexpected knock-on effects on plant community dynamics. We test the hypothesis that prolonged drought legacies cause shifts in PSFs due to changes in plant-soil biotic interactions.Methods PSFs of twelve plant species representing four functional groups (C3 and C4 grasses, forbs, and legumes) were assessed in monocultures, and communities composed of one species from each of the four functional groups, in soils collected from plots with a five-year legacy of ambient rainfall or drought conditions under laboratory conditions. Plants were grown under well-watered conditions, with observed effects, therefore, being related to field drought legacies rather than experimental drought. Sterile soil conditioning was included to assess shifts in plant-soil biotic interactions associated with field rainfall legacies explicitly.Results C3 and C4 grasses displayed negative and positive PSFs, respectively, in both rainfall legacies treatments. PSFs of Plantago lanceolata shifted from positive to negative in drought legacies, while Cichorium intybus showed neutral PSFs in both soils. PSFs of Medicago sativa shifted from negative to positive, while Biserrula pelecinus and Trifolium repens showed neutral PSFs, in prolonged drought legacies. PSFs at the community level showed a trend to shift from near-positive to neutral PSFs in soils with a drought legacy, with significant negative PSFs observed when comparing home versus sterile soils, suggesting that drought may destabilise plant communities. Conclusion Our results provide evidence that prolonged drought legacies can modify plant community dynamics due to species-specific changes in PSFs that persist after droughts are alleviated.


2014 ◽  
Vol 19 (2) ◽  
pp. 276-284 ◽  
Author(s):  
Joaquim S. Silva ◽  
Filipe X. Catry ◽  
Francisco Moreira ◽  
Tito Lopes ◽  
Tiago Forte ◽  
...  

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