Ungulates alter plant cover without consistent effect on soil ecosystem functioning

The Arctic is warming more than twice the global average. Graminoids, deciduous shrubs, and evergreen shrubs have been shown to increase in cover in some regions, but not others. To better understand why plant response varies across regions, we compared change in cover over time with nine functional traits of twelve dominant species at three regions in northern Alaska (Utqiaġvik, Atqasuk, and Toolik Lake). Cover was measured three times from 2008 to 2018. Repeated measures ANOVA found one species showed a significant change in cover over time; Carex aquatilis increased at Atqasuk by 12.7%. Canonical correspondence analysis suggested a relationship between shifts in species cover and traits, but Pearson and Spearman correlations did not find a significant trend for any trait when analyzed individually. Investigation of community-weighted means (CWM) for each trait revealed no significant changes over time for any trait at any region. Whereas, estimated ecosystem values for several traits important to ecosystem functioning showed consistent increases over time at two regions (Utqiaġvik and Atqasuk). Results thus indicate that vascular plant community composition and function have remained consistent over time; however, documented increases in total plant cover have important implications for ecosystem functioning.

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Early warning indicators of changes in soil ecosystem functioning

Ecological Indicators ◽

10.1016/j.ecolind.2014.09.017 ◽

2015 ◽

Vol 48 ◽

pp. 542-549 ◽

Cited By ~ 20

Author(s):

A. Muscolo ◽

G. Settineri ◽

E. Attinà

Keyword(s):

Early Warning ◽

Ecosystem Functioning ◽

Soil Ecosystem ◽

Early Warning Indicators ◽

Warning Indicators

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Restoring wetland prairies: tradeoffs among native plant cover, community composition, and ecosystem functioning

Ecosphere ◽

10.1890/es12-00261.1 ◽

2012 ◽

Vol 3 (12) ◽

pp. art121 ◽

Cited By ~ 12

Author(s):

Laurel Pfeifer-Meister ◽

Bart R. Johnson ◽

Bitty A. Roy ◽

Santiago Carreño ◽

Julie L. Stewart ◽

...

Keyword(s):

Community Composition ◽

Ecosystem Functioning ◽

Plant Cover ◽

Native Plant

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Wildfires decrease the local-scale ecosystem spatial variability of Pinus canariensis forests during the first two decades post fire

International Journal of Wildland Fire ◽

10.1071/wf18145 ◽

2019 ◽

Vol 28 (4) ◽

pp. 288

Author(s):

Jorge Durán ◽

Alexandra Rodríguez ◽

Javier Méndez ◽

Gustavo Morales ◽

José María Fernández-Palacios ◽

...

Keyword(s):

Spatial Variability ◽

Ecosystem Functioning ◽

Environmental Variables ◽

Local Scale ◽

Natural Disturbances ◽

Soil Arthropods ◽

Soil Ecosystem ◽

Pinus Canariensis ◽

Soil Variables ◽

Wide Range

The spatial variability (i.e. heterogeneity) of environmental variables determines a wide range of ecosystem features and plays a key role in regulating key ecosystem services. Wildfires are among the most significant natural disturbances that forests face, but our knowledge about their effect on ecosystem spatial variability is still limited. We used a 19-year fire chronosequence of natural, unmanaged Pinus canariensis C. Sm. ex DC forests to investigate how wildfires affect overall ecosystem spatial variability, as well as that of key faunal, plant and soil ecosystem attributes. The spatial variability of most soil variables and of the overall ecosystem tended to decrease after the fire and remain lower than the unburned plots even after 19 years. The spatial variability of plant-related variables, except for litter decomposition, as well as that of soil arthropods abundance, decreased more gradually than that of soil variables, reaching the lowest values in the plots burned 19 years before the survey. Our study provides evidence that wildfires are capable of significantly decreasing local-scale forest spatial heterogeneity through changes in the spatial variability of their different components, with likely yet unknown consequences for ecosystem functioning.

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APPLICATION OF A DROPLET-PIXE SYSTEM TO STUDY RADIATION EFFECTS ON ECOSYSTEM FUNCTIONING

International Journal of PIXE ◽

10.1142/s0129083507001216 ◽

2007 ◽

Vol 17 (03n04) ◽

pp. 161-167 ◽

Cited By ~ 3

Author(s):

N. ISHII ◽

S. HOMMA-TAKEDA ◽

K. TAGAMI ◽

S. FUMA ◽

H. TAKEDA

Keyword(s):

Liquid Phase ◽

Gamma Rays ◽

Ecosystem Functioning ◽

Radiation Effects ◽

Soil Ecosystem ◽

Pixe Analysis ◽

Dissolved Iron ◽

Liquid Phases ◽

Solid Soil

Droplet PIXE analysis was applied to the study of radiation effects on soil ecosystem functioning. A paddy soil sample was flooded with well water to prepare soil ecosystem specimens (microcosms), and then the microcosms were chronically exposed to gamma rays at a dose rate of 1 Gy day−1 for 5 days. After the final irradiation, a brownish discoloration was observed in the liquid phases of the irradiated microcosms.To clarify the factors causing the discoloration, minerals in the solutions of the microcosms were analyzed by the droplet PIXE system.Elemental profiles from the XRF spectrum showed marked iron peaks. Exposure of microcosms to gamma rays resulted in a decrease in the iron levels. Since iron is released in the form of Fe(II) from the solid soil to the liquid phase, further determination of the Fe (II) levels was performed. The percentages of Fe (II) to the total iron in the liquid phase of the irradiated microcosms were lower than those of the controls. This result may be caused by the change of Fe species from soluble Fe (II) to insoluble Fe (III) during gamma irradiation, and the Fe (III) species with a brownish color may be associated with the discoloration of the irradiated samples. The conversion from soluble to insoluble forms may also contribute the small amount of dissolved iron in the irradiated microcosms. Iron is an essential trace nutrient for plants, and thus the amount of dissolved iron is one aspect of ecosystem functioning. Effects of gamma radiation on the dissolved iron could involve a change in the soil ecosystem through the depression of iron flux in the long term.

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Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

Brazilian Journal of Biology ◽

10.1590/1519-6984.24814 ◽

2016 ◽

Vol 76 (3) ◽

pp. 686-691

Author(s):

F. Ospina-Bautista ◽

J. V. Estévez Varón

Keyword(s):

Species Richness ◽

Multiple Regression ◽

Leaf Litter ◽

Akaike Information Criterion ◽

Ecosystem Functioning ◽

Plant Cover ◽

Information Criterion ◽

Plant Structure ◽

Litter Accumulation ◽

The Relationship

Abstract Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.

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The interplay between facilitation and habitat type drive spatial vegetation patterns in global drylands

10.1101/227330 ◽

2017 ◽

Author(s):

Miguel Berdugo ◽

Santiago Soliveres ◽

Sonia Kéfi ◽

Fernando T. Maestre

Keyword(s):

Spatial Patterns ◽

Power Law ◽

Ecosystem Functioning ◽

Dominant Species ◽

Abiotic Factors ◽

Plant Cover ◽

Habitat Type ◽

Relative Importance ◽

Habitat Types ◽

Geographical Regions

ABSTRACTThe size distribution of discrete plant patches (PSD), a common descriptor of the spatial patterns of vascular vegetation, has been linked to variations in land degradation and ecosystem functioning in drylands. However, most studies on PSDs conducted to date have focused on a single or a few study sites within a particular region. Therefore, little is know on the general typology and distribution of PSDs at the global scale, and on the relative importance of biotic and abiotic factors as drivers of their variation across geographical regions and habitat types. We analyzed 115 dryland plant communities from all continents except Antarctica to investigate the general typology of PSDs, and to assess the relative importance of biotic (plant cover, frequency of facilitation, soil amelioration, height of the dominant species) and abiotic (aridity and sand content) factors as drivers of PSDs across contrasting habitat types (shrublands and grasslands). We found that both power-law and lognormal PSDs were generally distributed regardless of the region of the world considered. The percentage of facilitated species in the community drives the emergence of power-law like spatial patterns in both shrublands and grasslands, although mediated by different mechanisms (soil and climatic amelioration, respectively). Other drivers of PSDs were habitat-specific: height of the dominant species and total cover were particularly strong drivers in shrublands and grasslands, respectively. The importance of biotic attributes as drivers of PSDs declined under the most arid conditions in both habitats. We observed that PSDs deviated from power law functions not only due to the loss of large, but also of small patches. Our results expand our knowledge about patch formation in drylands and the habitat-dependency of their drivers. They also highlight different ways in which facilitation may act on ecosystem functioning through the formation of plant spatial patterns.

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