1
|
van Klink R, Bowler DE, Gongalsky KB, Shen M, Swengel SR, Chase JM. Disproportionate declines of formerly abundant species underlie insect loss. Nature 2024; 628:359-364. [PMID: 38123681 PMCID: PMC11006610 DOI: 10.1038/s41586-023-06861-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/10/2023] [Indexed: 12/23/2023]
Abstract
Studies have reported widespread declines in terrestrial insect abundances in recent years1-4, but trends in other biodiversity metrics are less clear-cut5-7. Here we examined long-term trends in 923 terrestrial insect assemblages monitored in 106 studies, and found concomitant declines in abundance and species richness. For studies that were resolved to species level (551 sites in 57 studies), we observed a decline in the number of initially abundant species through time, but not in the number of very rare species. At the population level, we found that species that were most abundant at the start of the time series showed the strongest average declines (corrected for regression-to-the-mean effects). Rarer species were, on average, also declining, but these were offset by increases of other species. Our results suggest that the observed decreases in total insect abundance2 can mostly be explained by widespread declines of formerly abundant species. This counters the common narrative that biodiversity loss is mostly characterized by declines of rare species8,9. Although our results suggest that fundamental changes are occurring in insect assemblages, it is important to recognize that they represent only trends from those locations for which sufficient long-term data are available. Nevertheless, given the importance of abundant species in ecosystems10, their general declines are likely to have broad repercussions for food webs and ecosystem functioning.
Collapse
Affiliation(s)
- Roel van Klink
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
- Department of Computer Science, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
| | - Diana E Bowler
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
- Department of Ecosystem Services, Helmholtz-Centre for Environmental Research (UFZ), Leipzig, Germany
- UK Centre for Ecology & Hydrology, Crowmarsh Gifford, UK
| | - Konstantin B Gongalsky
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation
| | - Minghua Shen
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department of Computer Science, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | | | - Jonathan M Chase
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department of Computer Science, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| |
Collapse
|
2
|
van Klink R, Bowler DE, Gongalsky KB, Chase JM. Long-term abundance trends of insect taxa are only weakly correlated. Biol Lett 2022; 18:20210554. [PMID: 35193369 PMCID: PMC8864342 DOI: 10.1098/rsbl.2021.0554] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Changes in the abundances of animals, such as with the ongoing concern about insect declines, are often assumed to be general across taxa. However, this assumption is largely untested. Here, we used a database of assemblage-wide long-term insect and arachnid monitoring to compare abundance trends among co-occurring pairs of taxa. We show that 60% of co-occurring taxa qualitatively showed long-term trends in the same direction-either both increasing or both decreasing. However, in terms of magnitude, temporal trends were only weakly correlated (mean freshwater r = 0.05 (±0.03), mean terrestrial r = 0.12 (±0.09)). The strongest correlation was between trends of beetles and those of moths/butterflies (r = 0.26). Overall, even though there is some support for directional similarity in temporal trends, we find that changes in the abundance of one taxon provide little information on the changes of other taxa. No clear candidate for umbrella or indicator taxa emerged from our analysis. We conclude that obtaining a better picture of changes in insect abundances will require monitoring of multiple taxa, which remains uncommon, especially in the terrestrial realm.
Collapse
Affiliation(s)
- Roel van Klink
- German Centre for Integrative Biodiversity research – iDiv - Halle-Jena-Leipzig, Puschstrasse 4, 04103 Leipzig, Germany,Department of Computer Science, Martin Luther University-Halle Wittenberg, 06099 Halle (Saale), Germany
| | - Diana E. Bowler
- German Centre for Integrative Biodiversity research – iDiv - Halle-Jena-Leipzig, Puschstrasse 4, 04103 Leipzig, Germany,Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Str. 159, 07743 Jena, Germany,Helmholtz - Centre for Environmental Research – UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Konstantin B. Gongalsky
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky pr., 33, Moscow 119071, Russia
| | - Jonathan M. Chase
- German Centre for Integrative Biodiversity research – iDiv - Halle-Jena-Leipzig, Puschstrasse 4, 04103 Leipzig, Germany,Department of Computer Science, Martin Luther University-Halle Wittenberg, 06099 Halle (Saale), Germany
| |
Collapse
|
3
|
van Klink R, Bowler DE, Gongalsky KB, Swengel AB, Gentile A, Chase JM. Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances. Science 2020; 368:417-420. [PMID: 32327596 DOI: 10.1126/science.aax9931] [Citation(s) in RCA: 372] [Impact Index Per Article: 93.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 03/03/2020] [Indexed: 01/16/2023]
Abstract
Recent case studies showing substantial declines of insect abundances have raised alarm, but how widespread such patterns are remains unclear. We compiled data from 166 long-term surveys of insect assemblages across 1676 sites to investigate trends in insect abundances over time. Overall, we found considerable variation in trends even among adjacent sites but an average decline of terrestrial insect abundance by ~9% per decade and an increase of freshwater insect abundance by ~11% per decade. Both patterns were largely driven by strong trends in North America and some European regions. We found some associations with potential drivers (e.g., land-use drivers), and trends in protected areas tended to be weaker. Our findings provide a more nuanced view of spatiotemporal patterns of insect abundance trends than previously suggested.
Collapse
Affiliation(s)
- Roel van Klink
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany. .,Leipzig University, 04109 Leipzig, Germany.,WBBS Foundation, 9409 TV, Loon, Netherlands
| | - Diana E Bowler
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany.,Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany.,Helmholtz Centre for Environmental Research (UFZ), 04318 Leipzig, Germany
| | - Konstantin B Gongalsky
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071, Russia.,M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | | | - Alessandro Gentile
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany
| | - Jonathan M Chase
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany.,Department of Computer Science, Martin Luther University-Halle Wittenberg, 06099 Halle (Saale), Germany
| |
Collapse
|
4
|
Ekholm A, Tack AJM, Pulkkinen P, Roslin T. Host plant phenology, insect outbreaks and herbivore communities - The importance of timing. J Anim Ecol 2019; 89:829-841. [PMID: 31769502 DOI: 10.1111/1365-2656.13151] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 10/27/2019] [Indexed: 01/19/2023]
Abstract
Climate change may alter the dynamics of outbreak species by changing the phenological synchrony between herbivores and their host plants. As host plant phenology has a genotypic component that may interact with climate, infestation levels among genotypes might change accordingly. When the outbreaking herbivore is active early in the season, its infestation levels may also leave a detectable imprint on herbivores colonizing the plant later in the season. In this study, we first investigated how the spring phenology and genotype of Quercus robur influenced the density of the spring-active, outbreaking leaf miner Acrocercops brongniardellus. We then assessed how intraspecific density affected the performance of A. brongniardellus and how oak genotype and density of A. brongniardellus affected the insect herbivore community. We found that Q. robur individuals of late spring phenology were more strongly infested by A. brongniardellus. Conspecific pupae on heavily infested oaks tended to be lighter, and fewer heterospecific insect herbivores colonized the oak later in the season. Beyond its effects through phenology, plant genotype left an imprint on herbivore species richness and on two insect herbivores. Our results suggest a chain of knock-on effects from plant phenology, through the outbreaking species to the insect herbivore community. Given the finding of how phenological synchrony between the outbreak species and its host plant influences infestation levels, a shift in synchrony may then change outbreak dynamics and cause cascading effects on the insect community.
Collapse
Affiliation(s)
- Adam Ekholm
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ayco J M Tack
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | | | - Tomas Roslin
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| |
Collapse
|
5
|
Obertegger U, Pindo M, Flaim G. Multifaceted aspects of synchrony between freshwater prokaryotes and protists. Mol Ecol 2019; 28:4500-4512. [DOI: 10.1111/mec.15228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/29/2019] [Accepted: 08/12/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Ulrike Obertegger
- Research and Innovation Centre Fondazione Edmund Mach San Michele all'Adige Italy
| | - Massimo Pindo
- Research and Innovation Centre Fondazione Edmund Mach San Michele all'Adige Italy
| | - Giovanna Flaim
- Research and Innovation Centre Fondazione Edmund Mach San Michele all'Adige Italy
| |
Collapse
|