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«Dime lo que comes y te diré lo que eres»

[Dis-moi ce que tu manges, je te dirai ce que tu es] Jean Anthelme Brillat-Savarin (1755-1826)

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Landscape complexity and US crop production  

Katherine S. Nelson & Emily K. Burchfield, 2021.

Agricultural expansion and intensification have simplified Earth’s landscapes, thereby adversely affecting the biodiversity and ecosystem services that support agricultural production. Field-scale research suggests that increased landcover complexity can improve crop productivity, but less is known about how complexity and crop productivity interact at broader landscape scales. This study evaluates the relationship between landscape complexity and crop yields for counties in the conterminous United States from 2008 to 2018. Our results suggest that the number and quantity of landcover categories on a landscape has a stronger influence on yields than how these landcover categories are arranged on the landscape. Specifically, increased landcover diversity is associated with yield increases for corn and wheat of more than 10%—an effect strength similar to the impact of seasonal precipitation and soil suitability. Notably, landscape configurations that are both moderately complex and also highly diverse are associated with yield increases of more than 20% for corn and wheat. Our findings suggest that increasing the complexity of landcover may provide a way to improve crop productivity in the United States without further extensification or intensification of agriculture.

https://www.nature.com/articles/s43016-021-00281-1

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Foto: Bruno Réquillart

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Individual‐based plant‐pollinator networks are structured by phenotypic and microsite plant traits 

Arroyo‐Correa et al., 2021

1. The biotic and abiotic context of individual plants within animal‐pollinated plant populations can influence pollinator foraging behavior. Pollinator movements regulate pollen flow among plant individuals, and ultimately determine individual plant reproductive success. Yet the underlying drivers of this context‐dependency of interactions at the population level and their functional consequences for individuals remain poorly known.
2. Here we used a well‐characterised population of Halimium halimifolium (Cistaceae), a Mediterranean shrub species, in combination with exponential random graph models (ERGMs) to evaluate how the intrapopulation variation in plant attributes configures individual‐based plant‐pollinator networks and determines their reproductive outcomes. Specifically, we assessed (i) how the intrinsic (i.e., phenotype and phenology) and extrinsic (i.e., microsite) plant attributes influenced the emerging configuration of the bipartite plant‐pollinator network and the unipartite plant‐plant network derived from pollinator sharing, and (ii) how these plant attributes combined with the network topological position of individual plants affect their female fitness, measured as the total seed weight per plant.
3. We found that both intrinsic and extrinsic plant attributes contributed substantially to explain the configuration of both the bipartite and the unipartite pollination network. Besides the effects of plant attributes, the functional group to which pollinator species belonged was also important to determine the variance in plant‐pollinator interaction odds, while the probability of plants to share more pollinator species was additionally influenced by the spatial distance between those plants. Further, our results showed that these influences of plant attributes on network structure can be translated into functional outcomes at the plant individual level, with direct consequences for intrapopulation fitness variation.
4. Synthesis. This study builds towards a better understanding of the multiple drivers underlying the context‐dependency of plant‐pollinator interactions and how they mediate the reproductive outputs for individual plants within a population. The application of our analytical framework allows a conceptual shift from descriptive to predictive research on the evolutionary and ecological processes that give rise to complex ecological networks at the population level. 
   

 

https://doi.org/10.1111/1365-2745.13694 

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May Flower

Emily Dickinson 

Pink, small, and punctual,

Aromatic, low,

Covert in April,

Candid in May,



Dear to the moss,

Known by the knoll,

Next to the robin

In every human soul.



Bold little beauty,

Bedecked with thee,

Nature forswears

Antiquity.

 

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Network motifs involving both competition and facilitation predict biodiversity in alpine plant communities 

Losapio et al., 2021

Biological diversity depends on multiple, cooccurring ecological interactions. However, most studies focus on one interaction type at a time, leaving community ecologists unsure of how positive and negative associations among species combine to influence biodiversity patterns. Using surveys of plant populations in alpine communities worldwide, we explore patterns of positive and negative associations among triads of species (modules) and their relationship to local biodiversity. Three modules, each incorporating both positive and negative associations, were overrepresented, thus acting as "network motifs." Furthermore, the overrepresentation of these network motifs is positively linked to species diversity globally. A theoretical model illustrates that these network motifs, based on competition between facilitated species or facilitation between inferior competitors, increase local persistence. Our findings suggest that the interplay of competition and facilitation is crucial for maintaining biodiversity.

 

Global map of alpine plant networks studied here. Red dots on the map indicate the spatial location of the networks, with a few networks plotted for reference. In the networks, green dots represent plant species, and blue and red arrows represent negative- and positive species associations, respectively. Dot size is proportional to species abundance. The four network modules analyzed here are represented at the bottom of the figure, from left to right: intransitive competition, facilitation-driven competition, and competition-driven facilitation 1 and 2.

https://bit.ly/3d2JvAC

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How do plants engage with beneficial microorganisms while at the same time restricting pathogens? 

 Cara Haney and David Thoms