Eltonian niche width determines range expansion success in ectomycorrhizal conifers

Niche and Range Shifts of the Fall Webworm (Hyphantria cunea Dury) in Europe Imply Its Huge Invasion Potential in the Future

The fall webworm (Hyphantria cunea Dury) has a strong impact on agricultural systems in Europe. However, its invasive potential, which was inherited from its native niche in North America, remains unknown. Here, we investigated the climatic niche and range shifts of the fall webworm in Europe and compared them with those in native North America, then assessed the worms' invasive potential in Europe. Compared with the fall webworm in Europe, those in North America survived in more diverse climatic conditions, which was closely associated with their broader niche and larger potential ranges in Europe. If the fall webworm in Europe could exploit the native niche inherited from those in North America to adapt to climatic conditions in Europe, their potential ranges in Europe could be 5.5-fold those based on the niche as introduced in Europe. The potentially unfilled ranges of the fall webworm in Europe were mainly detected in vast regions of Europe, excluding Norway, Sweden, Finland, North Russia, Hungary, Croatia, Romania, and Ukraine, suggesting that, without strict control, these vast regions might be preferably invaded by the fall webworm in Europe in the future. Therefore, strict control against its invasion is needed. Given that small niche shifts in this invasive insect could result in large range shifts, the niche shifts represent a more sensitive indicator of invasion risk than range shifts.

Global niche and range shifts of Batrachochytrium dendrobatidis, a highly virulent amphibian-killing fungus

Batrachochytrium dendrobatidis (Bd) is one of the world's most invasive species, and is responsible for chytridiomycosis, an emerging infectious disease that has caused huge losses of global amphibian biodiversity. Few studies have investigated invasive Bd's niche and range relative to those of native Bd. In the present study, we applied niche and range dynamic models to investigate global niche and range dynamics between native and invasive Bd. Invasive Bd occupied wider and different niche positions than did native Bd. Additionally, invasive Bd was observed in hotter, colder, wetter, drier, and more labile climatic conditions. Contrast to most relevant studies presuming Bd's niche remaining stable, we found that invasive Bd rejected niche conservatism hypotheses, suggesting its high lability in niche, and huge invasion potential. Bd's niche non-conservatism may result in range lability, and small niche expansions could induce large increases in range. Niche shifts may therefore be a more sensitive indicator of invasion than are range shifts. Our findings indicate that Bd is a high-risk invasive fungus not only due to its high infection and mortality rates, but also due to its high niche and range lability, which enhance its ability to adapt to novel climatic conditions. Therefore, invasive Bd should be a high-priority focus species in strategizing against biological invasions.

Light availability and light demand of plants shape the arbuscular mycorrhizal fungal communities in their roots

Plants involved in the arbuscular mycorrhizal (AM) symbiosis trade photosynthetically derived carbon for fungal-provided soil nutrients. However, little is known about how plant light demand and ambient light conditions influence root-associating AM fungal communities. We conducted a manipulative field experiment to test whether plants' shade-tolerance influences their root AM fungal communities in open and shaded grassland sites. We found similar light-dependent shifts in AM fungal community structure for experimental bait plant roots and the surrounding soil. Yet, deviation from the surrounding soil towards lower AM fungal beta-diversity in the roots of shade-intolerant plants in shade suggested preferential carbon allocation to specific AM fungi in conditions where plant-assimilated carbon available to fungi was limited. We conclude that favourable environmental conditions widen the plant biotic niche, as demonstrated here with optimal light availability reducing plants' selectivity for specific AM fungi, and promote compatibility with a larger number of AM fungal taxa.

Fungal functional ecology: bringing a trait-based approach to plant-associated fungi

Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro-organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function. Trait-based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and -omics-based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (Fun^Fun ). Fun^Fun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait-based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology.