How often are ecosystems top‐down controlled? Experiments in grassland, grasshopper, and bird systems over time and space DOI Creative Commons
Gary E. Belovsky, Jennifer B. Slade

Ecosphere, Journal Year: 2024, Volume and Issue: 15(11)

Published: Nov. 1, 2024

Abstract Ecosystems are frequently considered to be controlled by predation (top‐down). Experiments examined this in four bird/spider/grasshopper/prairie habitats over 34 years, employing each habitat three 100 m 2 bird exclosures and controls (121 habitat/year cases) where plant, grasshopper, spider abundances were measured. Top‐down control (plants decrease grasshoppers increase with exclusion) was observed only 13.2% of cases, while plants increased decreased 33.1% 25.6% 28.1% cases. Therefore, top‐down not common system responses constant, but varied among sites, directionally time climate change. This diversity is expected given the variety underlying processes complex ecosystems. For example, decision tree/discriminant analysis found that plant decreases increases exclusion correctly identified 78.3% cases grasshopper hatchling abundance, cover, annual net primary production (ANPP), 76.7% edible biomass per hatchling, large abundance. Analysis other system‐wide terrestrial trophic experiments indicates us space may so may, general, more variable than either or bottom‐up as often considered.

Language: Английский

How often are ecosystems top‐down controlled? Experiments in grassland, grasshopper, and bird systems over time and space DOI Creative Commons
Gary E. Belovsky, Jennifer B. Slade

Ecosphere, Journal Year: 2024, Volume and Issue: 15(11)

Published: Nov. 1, 2024

Abstract Ecosystems are frequently considered to be controlled by predation (top‐down). Experiments examined this in four bird/spider/grasshopper/prairie habitats over 34 years, employing each habitat three 100 m 2 bird exclosures and controls (121 habitat/year cases) where plant, grasshopper, spider abundances were measured. Top‐down control (plants decrease grasshoppers increase with exclusion) was observed only 13.2% of cases, while plants increased decreased 33.1% 25.6% 28.1% cases. Therefore, top‐down not common system responses constant, but varied among sites, directionally time climate change. This diversity is expected given the variety underlying processes complex ecosystems. For example, decision tree/discriminant analysis found that plant decreases increases exclusion correctly identified 78.3% cases grasshopper hatchling abundance, cover, annual net primary production (ANPP), 76.7% edible biomass per hatchling, large abundance. Analysis other system‐wide terrestrial trophic experiments indicates us space may so may, general, more variable than either or bottom‐up as often considered.

Language: Английский

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