scholarly journals Changes in plant-herbivore network structure and robustness along land-use intensity gradients in grasslands and forests

2021 ◽  
Vol 7 (20) ◽  
pp. eabf3985
Author(s):  
Felix Neff ◽  
Martin Brändle ◽  
Didem Ambarlı ◽  
Christian Ammer ◽  
Jürgen Bauhus ◽  
...  

Land-use intensification poses major threats to biodiversity, such as to insect herbivore communities. The stability of these communities depends on interactions linking herbivores and host plants. How interaction network structure begets robustness, and thus stability, in different ecosystems and how network structure and robustness are altered along land-use intensity gradients are unclear. We analyzed plant-herbivore networks based on literature-derived interactions and long-term sampling from 289 grasslands and forests in three regions of Germany. Network size and nestedness were the most important determinants of network robustness in both ecosystems. Along land-use intensity gradients, networks in moderately grazed grasslands were more robust than in those managed by frequent mowing or fertilization. In forests, changes of network robustness along land-use intensity gradients relied on changes in plant species richness. Our results expand our knowledge of the stability of plant-herbivore networks and indicate options for management aimed at stabilizing herbivore communities.

2018 ◽  
Vol 24 (7) ◽  
pp. 2828-2840 ◽  
Author(s):  
Valentin H. Klaus ◽  
Till Kleinebecker ◽  
Verena Busch ◽  
Markus Fischer ◽  
Norbert Hölzel ◽  
...  

Author(s):  
Patricia Landaverde-González ◽  
Eunice Enríquez ◽  
Juan Núñez-Farfán

AbstractIn recent years, evidence has been found that plant-pollinator interactions are altered by land-use and that genetic diversity also plays a role. However, how land-use and genetic diversity influence plant–pollinator interactions, particularly in the Neotropics, where many endemic plants exist is still an open question. Cucurbita pepo is a monoecious plant and traditional crop wide distributed, with high rates of molecular evolution, landraces associated with human cultural management and a history of coevolution with bees, which makes this species a promising model for studying the effect of landscape and genetic diversity on plant-pollinator interactions. Here, we assess (1) whether female and male flowers differences have an effect on the interaction network, (2) how C. pepo genetic diversity affects flower-bee visitation network structure, and (3) what is the effect that land-use, accounting for C. pepo genetic variability, has on pumpkin-bee interaction network structure. Our results indicate that female and male flowers presented the same pollinator community composition and interaction network structure suggesting that female/male differences do not have a significant effect on network evolution. Genetic diversity has a positive effect on modularity, nestedness and number of interactions. Further, the effect of semi-natural areas on nestedness could be buffered when genetic diversity is high. Our results suggest that considering genetic diversity is relevant for a better understanding of the effect of land-use on interaction networks. Additionally, this understanding has great value in conserving biodiversity and enhancing the stability of interaction networks in a world facing great challenges of habitat and diversity loss.


2008 ◽  
Vol 276 (1658) ◽  
pp. 903-909 ◽  
Author(s):  
D Kleijn ◽  
F Kohler ◽  
A Báldi ◽  
P Batáry ◽  
E.D Concepción ◽  
...  

Worldwide agriculture is one of the main drivers of biodiversity decline. Effective conservation strategies depend on the type of relationship between biodiversity and land-use intensity, but to date the shape of this relationship is unknown. We linked plant species richness with nitrogen (N) input as an indicator of land-use intensity on 130 grasslands and 141 arable fields in six European countries. Using Poisson regression, we found that plant species richness was significantly negatively related to N input on both field types after the effects of confounding environmental factors had been accounted for. Subsequent analyses showed that exponentially declining relationships provided a better fit than linear or unimodal relationships and that this was largely the result of the response of rare species (relative cover less than 1%). Our results indicate that conservation benefits are disproportionally more costly on high-intensity than on low-intensity farmland. For example, reducing N inputs from 75 to 0 and 400 to 60 kg ha −1  yr −1 resulted in about the same estimated species gain for arable plants. Conservation initiatives are most (cost-)effective if they are preferentially implemented in extensively farmed areas that still support high levels of biodiversity.


PLoS ONE ◽  
2015 ◽  
Vol 10 (1) ◽  
pp. e0115606 ◽  
Author(s):  
Walter Santos de Araújo ◽  
Marcos Costa Vieira ◽  
Thomas M. Lewinsohn ◽  
Mário Almeida-Neto

2019 ◽  
Vol 107 (6) ◽  
pp. 2635-2649 ◽  
Author(s):  
Deborah Schäfer ◽  
Valentin H. Klaus ◽  
Till Kleinebecker ◽  
Runa S. Boeddinghaus ◽  
Judith Hinderling ◽  
...  

Author(s):  
A.C.C. Coolen ◽  
A. Annibale ◽  
E.S. Roberts

This chapter reviews graph generation techniques in the context of applications. The first case study is power grids, where proposed strategies to prevent blackouts have been tested on tailored random graphs. The second case study is in social networks. Applications of random graphs to social networks are extremely wide ranging – the particular aspect looked at here is modelling the spread of disease on a social network – and how a particular construction based on projecting from a bipartite graph successfully captures some of the clustering observed in real social networks. The third case study is on null models of food webs, discussing the specific constraints relevant to this application, and the topological features which may contribute to the stability of an ecosystem. The final case study is taken from molecular biology, discussing the importance of unbiased graph sampling when considering if motifs are over-represented in a protein–protein interaction network.


2016 ◽  
pp. rtw062 ◽  
Author(s):  
Valentin H. Klaus ◽  
Deborah Schäfer ◽  
Till Kleinebecker ◽  
Markus Fischer ◽  
Daniel Prati ◽  
...  

2021 ◽  
Author(s):  
Anna Kirschbaum ◽  
Oliver Bossdorf ◽  
J F Scheepens

Abstract Aims Plant populations in managed grasslands are subject to strong selection exerted by grazing, mowing and fertilization. Many previous studies showed that this can cause evolutionary changes in mean trait values, but little is known about the evolution of phenotypic plasticity in response to land use. In this study, we aimed to elucidate the relationships between phenotypic plasticity – specifically, regrowth ability after biomass removal – and the intensity of grassland management and levels of temporal variation therein. Methods We conducted an outdoor common garden experiment to test if plants from more intensively mown and grazed sites showed an increased ability to regrow after biomass removal. We used three common plant species from temperate European grasslands, with seed material from 58 – 68 populations along gradients of land-use intensity, ranging from extensive (only light grazing) to very intensive management (up to four cuts per year). Important findings In two out of three species, we found significant population differentiation in regrowth ability after clipping. While variation in regrowth ability was unrelated to the mean land-use intensity of populations of origin, we found a relationship with its temporal variation in P. lanceolata, where plants experiencing less variable environmental conditions over the last 11 years showed stronger regrowth in reproductive biomass after clipping. Therefore, while mean grazing and mowing intensity may not select for regrowth ability, the temporal stability of the environmental heterogeneity created by land use may have caused its evolution in some species.


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