A new study published in the journal Ecology presents biogeochemical evidence to address the question of whether ecosystem nutrient limitation patterns shift from N-limitation to P-limitation under anthropogenic N enrichment. Figure: Wang, et al. Ecology, 2021
Nitrogen
enrichment buffers phosphorus limitation by mobilizing mineral-bound soil
phosphorus in grasslands. Phosphorus (P) limitation is expected to increase due
to nitrogen (N)-induced terrestrial eutrophication, although most soils contain
large P pools immobilized in minerals (Pi) and organic matter (Po).
In a new
study published in the journal Ecology
authors assessed whether transformations of these P pools can increase plant
available pools alleviating P limitation under enhanced N availability.
The
mechanisms underlying these possible transformations were explored by combining
results from a 10-year field N-addition experiment and a 3700-km transect
covering wide ranges in soil pH, soil N, aridity, leaching, and weathering that
can affect soil P status in grasslands.
“Nitrogen
addition promoted dissolution of immobile Pi (mainly Ca-bound recalcitrant P)
to more available forms of Pi (including Al- and Fe-bound P fractions and Olsen
P) by decreasing soil pH from 7.6 to 4.7, but did not affect Po”, explain Dr. Wang
from State Key Laboratory of Vegetation and Environmental Change, Institute of
Botany, Chinese Academy of Sciences, Beijing, China.
According to
this study, soil total P declined by 10% from 385±6.8 to 346±9.5 mg kg-1, while
available-P increased by 546% from 3.5±0.3 to 22.6±2.4 mg kg-1 after 10-year N
addition experiment, associated with an increase in Pi mobilization, plant uptake,
and leaching. Similar to the N-addition experiment, the drop in soil pH from 7.5
to 5.6 and increase in soil N concentration along the grassland transect were associated
with an increased ratio between relatively mobile Pi and immobile Pi.
These results
provide a new mechanistic understanding of the important role of soil Pi mobilization
in maintaining plant P supply and accelerating biogeochemical P cycles under
anthropogenic N enrichment. This mobilization process temporarily buffers ecosystem
P-limitation or even causes P eutrophication but will extensively deplete soil
P pools in the long run
“Our results
also suggest that ecosystem P cycling model predictions should incorporate the
interactions of N and P cycles by considering N enrichment effects on accelerating
soil P cycling rates, that models can be further refined via delineating the
dependence of Pi transformation on precipitation, and the ubiquitous role of
soil pH in driving the biogeochemical pathways of Pi transformation”, concludes
Prof. Josep Penuelas from CREAF-CSIC Barcelona.
A new study published in Nature Ecology and Evolution presents the first global quantification of how interactions of climate and soil drive variation in plant form and function. Map shows the ecoregions (30) included in the study, the number of species per ecoregion is colour-coded (from white= few, yellow= medium to red=many measurements). Source: Joswig et al. Nat. Ecol. Evol. (2021)
Summary:
An international research team succeeded in
identifying global factors that explain the diversity of form and function in
plants. Led by the University of Zurich, the Max Planck Institute for
Biogeochemistry in Jena and the University of Leipzig, the researchers
collected and analyzed plant data from around the world. For the first time,
they showed for characteristics such as plant size, structure, and life span
how strongly these are determined by climate and soil properties. Insights
derived from this could be crucial to improving Earth system models with regard
to the role of plant diversity.
(max. 700 chars)
At first glance,
the diversity of plant form and function seems difficult to comprehend.
However, it can be described in terms of morphological, physiological, and
biochemical characteristics. It has been shown previously that traits across
species fall into two main categories within which each plant must maintain a
balance: first, size and second, economy of metabolism. In a recent study in
Nature Ecology and Evolution, a team of researchers has now confirmed for the
first time, using a greatly enlarged global dataset for 17 different plant
traits, that these two main categories apply to all plants studied worldwide.
In the size category, plants balance height, leaf size, and seed size, among
other traits. These traits are also influenced by hydraulic components of water
transport in plants. The economics category describes how quickly and
effectively the plant gains energy and biomass through photosynthesis, balanced
against how long it survives. This category is determined by measurable
characteristics such as the structure and composition of the leaves in terms of
leaf area, as well as their elemental composition (nitrogen, phosphorus and
carbon). The team showed that life strategies of the plant species collected
worldwide in the TRY database are well explained by these two main categories.
Plant traits are
influenced by a wide variety of external factors, such as climate, soil
conditions, and human intervention. It has not yet been possible to determine
which factors are decisive at the global level. To answer this question, the
research team, led by Julia Joswig at the University of Zurich and the Max
Planck Institute for Biogeochemistry in Jena, analyzed the characteristics of
over 20,000 species. Information on climate and soil conditions at the location
of each plant was included in the analysis.
“Our study
clearly demonstrates that plant traits worldwide can be explained by joint
effects of climate and soil,” Joswig said, adding, “This suggests
that aspects of climate change and soil erosion, both of which occur as a
result of land use change, for example, should be researched together.”
Many of the
relationships described here were already known from small-scale, local
studies. “But the fact that these processes could now be shown globally
and their significance quantified is an important milestone,” adds Prof.
Miguel Mahecha of the University of Leipzig. “Studies of this kind can
guide global Earth system models to represent the complex interaction of
climate, soil and biodiversity, which is an important prerequisite for future
predictions,” Mahecha adds.
As expected, the
study shows how the height of plant species changes along latitudes, due to
differences in climate. However, the economic traits of plants do not show this
gradient. Similarly, soil quality is only partially affected by climate, so
there is a latitude-independent component in information about soil. Joswig and
her colleagues show that this soil information is also relevant for the economic
traits. Besides climate, soil-forming factors include organisms living in the
soil, geology and topography, and of course time. Global change affects
climate, organisms, and to some extent topography. Therefore, the study
suggests that global risks to plant life should be explored especially in
relation to climate change and soil erosion.
“In conclusion, our study
contribute to the advance of our understanding of broad scale plant functional
patterns. In particular, we highlight the combination of independent and
particularly joint effects of climate and soil on trait variation, an interaction
which has to date been neglected because few studies include both in a single
analysis, at the global scale as we have done here”, concludes Prof. Josep
Peñuelas from CREAF-CSIC.
Acknowledgments: This study used plant trait
data from a collection of datasets made available in the TRY database at
MPI-BGC.
Original publication:
Climatic and soil factors explain the two-dimensional spectrum of
global plant trait variation
Julia S. Joswig, Christian Wirth, Meredith C.
Schuman, Jens Kattge, Björn Reu, Ian J. Wright, Sebastian D. Sippel, Nadja
Rüger, Ronny Richter, Michael E. Schaepman, Peter M. van Bodegom, J. H. C.
Cornelissen, Sandra Díaz, Wesley N. Hattingh, Koen Kramer, Frederic Lens, Ülo
Niinemets, Peter B. Reich, Markus Reichstein, Christine Römermann, Franziska
Schrodt, Madhur Anand, Michael Bahn, Chaeho Byun, Giandiego Campetella, Bruno
E. L. Cerabolini, Joseph M. Craine, Andres Gonzalez-Melo, Alvaro G. Gutierrez,
Tianhua He, Pedro Higuchi, Herve Jactel, Nathan J. B. Kraft, Vanessa Minden, Vladimir
Onipchenko, Josep Penuelas, Valerio D. Pillar, Enio Sosinski, Nadejda A.
Soudzilovskaia, Evan Weiher, Miguel D. Mahecha. Nature Ecology and Evolution
(2021) DOI 10.1038/s41559-021-01616-8
