Global-scale latitudinal patterns of plant fine-root nitrogen and phosphorus

© 2019 John Wiley & Sons Ltd Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by human activities. Here, we aim to describe large-scale patterns of species richness and diversity in terrestrial vertebrate scavenger (carrion-consuming) assemblages, which provide key ecosystem functions and services. We used a worldwide dataset comprising 43 sites, where vertebrate scavenger assemblages were identified using 2,485 carcasses monitored between 1991 and 2018. First, we evaluated how scavenger richness (number of species) and diversity (Shannon diversity index) varied among seasons (cold vs. warm, wet vs. dry). Then, we studied the potential effects of human impact and a set of macroecological variables related to climatic conditions on the scavenger assemblages. Vertebrate scavenger richness ranged from species-poor to species rich assemblages (4–30 species). Both scavenger richness and diversity also showed some seasonal variation. However, in general, climatic variables did not drive latitudinal patterns, as scavenger richness and diversity were not affected by temperature or rainfall. Rainfall seasonality slightly increased the number of species in the community, but its effect was weak. Instead, the human impact index included in our study was the main predictor of scavenger richness. Scavenger assemblages in highly human-impacted areas sustained the smallest number of scavenger species, suggesting human activity may be overriding other macroecological processes in shaping scavenger communities. Our results highlight the effect of human impact at a global scale. As species-rich assemblages tend to be more functional, we warn about possible reductions in ecosystem functions and the services provided by scavengers in human-dominated landscapes in the Anthropocene.

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Habitat and leaf habit as determinants of growth, nutrient absorption, and nutrient use by Alaskan taiga forest species

Canadian Journal of Forest Research ◽

10.1139/x83-111 ◽

1983 ◽

Vol 13 (5) ◽

pp. 818-826 ◽

Cited By ~ 28

Author(s):

F. Stuart Chapin III ◽

Peter R. Tryon

Keyword(s):

Seasonal Pattern ◽

Nitrogen Concentration ◽

Leaf Nitrogen ◽

Leaf Biomass ◽

Deciduous Species ◽

Nitrogen And Phosphorus ◽

Leaf Respiration ◽

Phosphate Absorption ◽

Leaf Habit ◽

Root Nitrogen

Four evergreen and four deciduous trees and shrubs were sampled from habitats with differing soil temperature regimes in interior Alaskan forests to examine the relative importance of habitat and leaf habit in determining seasonal patterns of shoot growth, tissue nutrient concentration, respiration rate, and phosphate absorption rate. Leaf habit was the primary determinant of shoot growth, with deciduous species producing leaf area and leaf biomass earlier in the season than evergreens. Deciduous trees produced more biomass per shoot and per unit ground area than did evergreens. The seasonal pattern of leaf nitrogen and phosphorus concentration was correlated closely with patterns of leaf growth, declining through the growing season in deciduous species first as nutrient concentrations were diluted by increasing leaf biomass and later as nutrients were retranslocated from senescing leaves. In evergreens the seasonal decline in nutrient concentration was entirely due to dilution by increasing leaf biomass, and there was no evidence of autumn retranslocation from 1st-year leaves. In contrast to seasonal pattern, the magnitude of leaf phosphorus and root nitrogen and phosphorus concentrations was correlated more closely with habitat than with leaf habit, generally being lower in cold sites. Leaf respiration was highly correlated with leaf nitrogen concentration, so that the seasonal pattern of leaf respiration was determined primarily by leaf habit, whereas the magnitude of respiration was more closely correlated with habitat. Root respiration showed no consistent correlation with either habitat or leaf habit but was lower than leaf respiration, as would be expected from low root nitrogen concentration. Phosphate absorption rate was determined more strongly by habitat than by leaf habit, being lower in cold sites characterized by slow plant growth and consequently low annual nutrient requirement. Evergreen species were more effective at absorbing phosphate at low solution concentrations than were deciduous species. Phosphate absorption was less temperature sensitive than root respiration, so that roots of all species absorbed more phosphorus per unit of carbon respired at low root temperature.

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Fine-root biomass and nutrient cycling in Aristida stricta in a North Carolina coastal plain savanna

Canadian Journal of Botany ◽

10.1139/b84-120 ◽

1984 ◽

Vol 62 (4) ◽

pp. 823-829 ◽

Cited By ~ 18

Author(s):

Kathryn A. Saterson ◽

Peter M. Vitousek

Keyword(s):

North Carolina ◽

Coastal Plain ◽

Root Biomass ◽

Fine Root ◽

Fine Root Biomass ◽

Low Fertility ◽

Root Production ◽

Nitrogen And Phosphorus ◽

Different Tissues ◽

Slow Turnover

Seasonal changes in total fine-root biomass and the allocations of nitrogen and phosphorus to roots, root crowns, and leaves of Aristida stricta were measured on a North Carolina coastal plain savanna. Total fine-root biomass was determined from sequential root cores taken over 12 months. Total root biomass decreased from spring to late fall and then increased in winter. Root production and turnover estimates indicate that this low-fertility savanna has a relatively large root biomass and slow turnover. The pattern of allocation of biomass, nitrogen, and phosphorus to different tissues of Aristida stricta indicates that throughout the year the greatest percentage of biomass and nutrients is in roots.

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Non-mycorrhizal root associated fungi of a tropical montane forest are relatively robust to the long-term addition of moderate rates of nitrogen and phosphorus

10.1101/2021.08.11.455858 ◽

2021 ◽

Author(s):

Juan F. Dueñas ◽

Stefan Hempel ◽

Jürgen Homeier ◽

Juan Pablo Suárez ◽

Matthias C Rillig ◽

...

Keyword(s):

Community Composition ◽

Mycorrhizal Fungi ◽

Fine Root ◽

Montane Forest ◽

Tropical Montane Forest ◽

Nitrogen And Phosphorus ◽

Mycorrhizal Root ◽

Wide Range ◽

Soil Eutrophication

Andean forests are biodiversity hotspots and globally important carbon (C) repositories. This status might be at risk due to increasing rates of atmospheric nutrient deposition. As fungal communities are key in the recirculation of soil nutrients, assessing their responses to soil eutrophication can help establish a link between microbial biodiversity and the sustainability of the C sink status of this region. Beyond mycorrhizal fungi, which have been studied more frequently, a wide range of other fungi associate with the fine root fraction of trees. Monitoring these communities can offer insights into how communities composed of both facultative and obligate root associated fungi are responding to soil eutrophication. Here we document the response of non-mycorrhizal root associated fungal (RAF) communities to a long-term nutrient manipulation experiment. The stand level fine root fraction of an old growth tropical montane forest was sampled after seven years of nitrogen (N) and phosphorus (P) additions. RAF communities were characterized by a deep sequencing approach. As per the resource imbalance model, we expected that asymmetries in the availability of C, N and P elicited by fertilization will lead to mean richness reductions and alterations of the community structure. We recovered moderately diverse fungal assemblages composed by sequence variants classified within a wide set of trophic guilds. While mean richness remained stable, community composition shifted, particularly among Ascomycota and after the addition of P. Fertilization factors, however, only accounted for a minor proportion of the variance in community composition. These findings suggest that, unlike mycorrhizal fungi, RAF communities are less sensitive to shifts in soil nutrient availability. A plausible explanation is that non-mycorrhizal RAF have fundamentally different nutrient acquisition and life history traits, thus allowing them greater stoichiometric plasticity and an array of functional acclimation responses that collectively express as subtle shifts in community level attributes.

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