Removal of an apex predator initiates a trophic cascade that extends from herbivores to vegetation and the soil nutrient pool

It is widely assumed that organisms at low trophic levels, particularly microbes and plants, are essential to basic services in ecosystems, such as nutrient cycling. In theory, apex predators' effects on ecosystems could extend to nutrient cycling and the soil nutrient pool by influencing the intensity and spatial organization of herbivory. Here, we take advantage of a long-term manipulation of dingo abundance across Australia's dingo-proof fence in the Strzelecki Desert to investigate the effects that removal of an apex predator has on herbivore abundance, vegetation and the soil nutrient pool. Results showed that kangaroos were more abundant where dingoes were rare, and effects of kangaroo exclusion on vegetation, and total carbon, total nitrogen and available phosphorus in the soil were marked where dingoes were rare, but negligible where dingoes were common. By showing that a trophic cascade resulting from an apex predator's lethal effects on herbivores extends to the soil nutrient pool, we demonstrate a hitherto unappreciated pathway via which predators can influence nutrient dynamics. A key implication of our study is the vast spatial scale across which apex predators' effects on herbivore populations operate and, in turn, effects on the soil nutrient pool and ecosystem productivity could become manifest.

Download Full-text

Faculty Opinions recommendation of Removal of an apex predator initiates a trophic cascade that extends from herbivores to vegetation and the soil nutrient pool.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727610910.793550704 ◽

2018 ◽

Author(s):

Lauri Oksanen

Keyword(s):

Trophic Cascade ◽

Soil Nutrient ◽

Apex Predator ◽

Nutrient Pool

Download Full-text

Mesopredator suppression by an apex predator alleviates the risk of predation perceived by small prey

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.2870 ◽

2015 ◽

Vol 282 (1802) ◽

pp. 20142870 ◽

Cited By ~ 34

Author(s):

Christopher E. Gordon ◽

Anna Feit ◽

Jennifer Grüber ◽

Mike Letnic

Keyword(s):

Population Level ◽

Trophic Levels ◽

Foraging Efficiency ◽

Apex Predator ◽

Apex Predators ◽

Small Prey ◽

Positive Effects ◽

Risk Of Predation ◽

Habitat Breadth ◽

Access To Food

Predators can impact their prey via consumptive effects that occur through direct killing, and via non-consumptive effects that arise when the behaviour and phenotypes of prey shift in response to the risk of predation. Although predators' consumptive effects can have cascading population-level effects on species at lower trophic levels there is less evidence that predators' non-consumptive effects propagate through ecosystems. Here we provide evidence that suppression of abundance and activity of a mesopredator (the feral cat) by an apex predator (the dingo) has positive effects on both abundance and foraging efficiency of a desert rodent. Then by manipulating predators' access to food patches we further the idea that apex predators provide small prey with refuge from predation by showing that rodents increased their habitat breadth and use of ‘risky′ food patches where an apex predator was common but mesopredators rare. Our study suggests that apex predators' suppressive effects on mesopredators extend to alleviate both mesopredators' consumptive and non-consumptive effects on prey.

Download Full-text

Effects of Detritivores on Nutrient Dynamics and Corn Biomass in Mesocosms

Insects ◽

10.3390/insects10120453 ◽

2019 ◽

Vol 10 (12) ◽

pp. 453

Author(s):

Josephine Lindsey-Robbins ◽

Angélica Vázquez-Ortega ◽

Kevin McCluney ◽

Shannon Pelini

Keyword(s):

Nutrient Cycling ◽

Soil Solution ◽

Nutrient Dynamics ◽

Nutrient Management ◽

Soil Health ◽

Soil Nutrient ◽

Freshwater Ecosystems ◽

Significant Interaction Effect ◽

Total N ◽

Soil Nutrient Cycling

(1) Background: Strategies aimed at managing freshwater eutrophication should be based on practices that consider cropland invertebrates, climatic change, and soil nutrient cycling. Specifically, detritivores play a crucial role in the biogeochemical processes of soil through their consumptive and burrowing activities. Here, we evaluated the effectiveness of increasing detritivore abundance as a strategy for nutrient management under varied rainfall. (2) Methods: We manipulated soil macroinvertebrate abundance and rainfall amount in an agricultural mesocosms. We then measured the phosphorus, nitrogen, and carbon levels within the soil, corn, invertebrates, and soil solution. (3) Results: Increasing detritivore abundance in our soil significantly increased corn biomass by 2.49 g (p < 0.001), reduced weed growth by 18.2% (p < 0.001), and decreased soil solution nitrogen and total organic carbon (p < 0.05) and volume by 31.03 mL (p < 0.001). Detritivore abundance also displayed a significant interaction effect with rainfall treatment to influence soil total P (p = 0.0019), total N (p < 0.001), and total C (p = 0.0146). (4) Conclusions: Soil detritivores play an important role in soil nutrient cycling and soil health. Incorporating soil macroinvertebrate abundance into management strategies for agricultural soil may increase soil health of agroecosystems, preserve freshwater ecosystems, and protect the valuable services they both provide for humans.

Download Full-text

Linking Biogeochemical Cycles to Cattle Pasture Management and Sustainability in The Amazon Basin

The Biogeochemistry of the Amazon Basin ◽

10.1093/oso/9780195114317.003.0009 ◽

2001 ◽

Cited By ~ 1

Author(s):

Moacyr B. Dias-Filho ◽

Eric A. Davidson

Keyword(s):

Nutrient Cycling ◽

Soil Fertility ◽

Amazon Basin ◽

Nutrient Dynamics ◽

Soil Nutrient ◽

Biogeochemical Cycles ◽

Rapid Decline ◽

Forest Land ◽

Cattle Pasture ◽

Degraded Pasture

Pasture development has become the largest anthropogenic disturbance of forest land in the Amazon basin (Skole et al. 1994, Serrão and Toledo 1990). The area of forests converted to cattle pasture in Amazonia is currently estimated at approximately 20 million hectares. In the Brazilian Amazon basin, most of the conversion of forest land to pasture began during the early 1960s to the late 1980s, as a consequence of the opening of Amazon highways and government policies aimed at regional development (Hecht 1982, Nepstad et al. 1991, Serrão et al. 1979). Pasture productivity and longevity in the Amazon basin seem to be closely related to soil fertility and nutrient cycling (e.g., Dias Filho and Serrão 1987, Serrão et al. 1979). Thus, understanding the major biogeochemical cycles that influence soil fertility under pasture is vital for predicting the consequences of continued conversion of tropical forests to cattle pastures. This understanding is also important for devising management technologies that enhance the sustainability of these areas and thus slow further deforestation. Although during the first three to five years after establishment, the productivity of pastures is often good, after that period a rapid decline in productivity of the planted grasses associated with an increased presence of herbaceous and woody invaders is generally observed (reviewed by Serrão and Toledo 1990). If left uncontrolled, these invader species slowly become dominant and lead to “pasture degradation,” a condition characterized by a complete dominance of the weedy community. If left to secondary succession, forest vegetation usually becomes reestablished on these degraded pasture lands in the Amazon, although the species composition is usually different than that of the primary forest (Nepstad 1989). The nutrient status of the degraded pasture soils is among the factors that affect the rate of regrowth of the secondary forests. One of the first attempts to study soil nutrient dynamics under cultivated pastures in the Amazon basin was conducted in the early 1970s by Falesi (1976). The results of that chronosequence study in different soil types suggested that soil nutrient cycling in pastures differed from that of the traditional slash-and-burn agriculture.

Download Full-text

Return of an apex predator to a suburban preserve triggers a rapid trophic cascade

10.1101/564294 ◽

2019 ◽

Cited By ~ 3

Author(s):

Kevin Leempoel ◽

Jordana Meyer ◽

Trevor Hebert ◽

Nicole Nova ◽

Elizabeth A. Hadly

Keyword(s):

Trophic Cascade ◽

Puma Concolor ◽

Activity Patterns ◽

Diel Activity ◽

Urban Landscapes ◽

Apex Predator ◽

Apex Predators ◽

Non Invasive ◽

And Behavior ◽

Fecal Sampling

ABSTRACTAbsence of apex predators simplifies food chains, leading to trophic degradation of ecosystems and diminution of the services they provide1. However, most predators do not coexist well with humans, which has resulted in a decline of carnivores and functional ecosystems worldwide2. In some instances, cryptic carnivores manage to survive amidst human settlements, finding refuge in small biological islands surrounded by urban landscapes. In such a system, we used two non-invasive data collection methods (camera trapping and fecal sampling) to investigate the multiannual relationship between predators and prey, and between competitors, through analysis of: (1) relative abundance and detection probability of species over time, (2) causal interactions via empirical dynamic modeling, (3) diet, and (4) diel activity patterns. All approaches show concordance in the results: the natural return of an apex predator, the puma (Puma concolor), triggered a trophic cascade, affecting the abundance and behavior of its main prey, subordinate predators and other prey in the studied system. Our study demonstrates that trophic recovery can occur rapidly following the return of a top predator, even in small protected areas in increasingly urbanized landscapes.

Download Full-text

Using Knowledge of Soil Nutrient Cycling Processes to Design Sustainable Agriculture

Journal of Sustainable Agriculture ◽

10.1300/j064v02n03_06 ◽

1992 ◽

Vol 2 (3) ◽

pp. 63-82 ◽

Cited By ~ 34

Author(s):

P. F. Hendrix ◽

D. C. Coleman ◽

D. A. Crossley

Keyword(s):

Nutrient Cycling ◽

Sustainable Agriculture ◽

Soil Nutrient ◽

Soil Nutrient Cycling

Download Full-text

Whole-tree Harvesting Depletes Soil Nutrients

Canadian Journal of Forest Research ◽

10.1139/x74-077 ◽

1974 ◽

Vol 4 (4) ◽

pp. 530-535 ◽

Cited By ~ 39

Author(s):

Edwin H. White

Keyword(s):

Soil Nutrients ◽

Nutrient Removal ◽

Cropping Systems ◽

Soil Nutrient ◽

Site Conditions ◽

Nutrient Pool ◽

Whole Tree Harvesting ◽

The Impact ◽

Whole Tree ◽

Tree Harvesting

This paper reports the effects of whole-tree harvesting of eight cottonwood stands on the soil nutrient pool. The data indicate possible site degradation by depletion of soil reserves of N, P, and K but not Ca and Mg on a range of alluvial site conditions in Alabama. Foresters must establish the rate of nutrient removal in intensive tree cropping systems for a variety of species and sites and develop prescriptions to minimize the impact.

Download Full-text

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

10.5194/egusphere-egu21-15676 ◽

2021 ◽

Author(s):

Victor Burgeon ◽

Julien Fouché ◽

Sarah Garré ◽

Ramin Heidarian-Dehkordi ◽

Gilles Colinet ◽

...

Keyword(s):

Nutrient Cycling ◽

Soil Solution ◽

Nutrient Dynamics ◽

Chemical Properties ◽

Crop Productivity ◽

Nutrient Concentrations ◽

Soil Productivity ◽

Long Term Effects ◽

Mitigation And Adaptation

The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short&#8201;and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.

Download Full-text