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Contrasting latitudinal patterns in diversity and stability in a high-latitude species-rich moth community

Citation

Antão, Laura; Pöyry, Juha; Leinonen, Reima; Roslin, Tomas (2020), Contrasting latitudinal patterns in diversity and stability in a high-latitude species-rich moth community, Dryad, Dataset, https://doi.org/10.5061/dryad.905qfttgj

Abstract

Aim

Biodiversity is currently undergoing rapid restructuring across the globe. However, the nature of biodiversity change is not well understood, as community‐level changes may hide differential responses in individual population trajectories. Here, we quantify spatio‐temporal community and stability dynamics using a long‐term high‐quality moth monitoring dataset.

Location

Finland, Northern Europe.

Time period

1993–2012.

Major taxa studied

Nocturnal moths (Lepidoptera).

Methods

We quantified patterns of change in species richness, total abundance, dominance and temporal variability at different organizational levels over a 20 year period and along a latitudinal gradient of 1,100 km. We used mixed‐effects and linear models to quantify temporal trends for the different community and stability metrics and to test for latitudinal (or longitudinal) effects.

Results

We found contrasting patterns for different community metrics, and strong latitudinal patterns. While total moth abundance has declined, species richness has simultaneously increased over the study period, but with rates accelerating with latitude. In addition, we revealed a latitudinal pattern in temporal variability—the northernmost locations exhibited higher variability over time, as quantified by both metrics of richness and aggregated species population trends.

Main conclusions

When combined, our findings likely reflect an influx of species expanding their ranges poleward in response to warming. The overall decline in abundance and the latitudinal effect on temporal variability highlight potentially severe consequences of global change for community structure and integrity across high‐latitude regions. Importantly, our results underscore that increases in species richness may be paralleled by a loss of individuals, which in turn might affect higher trophic levels. Our findings suggest that the ongoing global species redistribution is affecting both community structure and stability over time, leading to compounded and partly opposing effects of global change depending on which biodiversity dimension we focus on.

Methods

The National Moth Monitoring scheme is coordinated by the Finnish Environment Institute (SYKE), running annually since 1993 (Leinonen et al., 2016, 2017). Nocturnal moths were sampled using “Jalas” light traps (Jalas, 1960) equipped with Hg vapour bulbs, located mainly in forested areas across Finland (66% of the traps). The traps were located in the same location from year to year and usually emptied weekly. Sampling occurs every night from early spring (after snowmelt) to late autumn (night frosts and at least one empty trapping period, i.e. one week). Sampling effort is constant across years for each trap, but as sampling aims to cover the entire moth activity period at each location, the trapping period is longer in more southern traps. Voluntary observers identified the specimens (Leinonen et al., 2016), with variable number of traps being sampled per year.

The data used here consists of records of abundance per species collected from 65 traps (unique Trap Code, with unique coordinates) with at least 8 years of sampling between 1993 and 2012. We used data sampled between April and October (sparse records outside this period were excluded). The data included observations of over 4 million individuals and 782 taxa, and specifically 734 moth species. For the species richness and stability metrics, records not identified to the species level were excluded, but such records were included for measures of abundance.

 

Leinonen, R., Pöyry, J., Söderman, G. & Tuominen-Roto, L. (2016) Suomen yöperhosseuranta (Nocturna) 1993-2012 [The Finnish moth monitoring scheme (Nocturna) 1993-2012], Suomen ympäristökeskuksen raportteja, 15/2016.

Leinonen, R., Pöyry, J., Söderman, G. & Tuominen-Roto, L. (2017) Suomen yöperhosyhteisöt muutoksessa – valtakunnallisen yöperhosseurannan keskeisiä tuloksia 1993–2012. Baptria, 42, 74–92.

Usage Notes

Data files contain the necessary data to perform the analyses in the linked manuscript. For each Trap, we report their unique location coordinates and bioclimatic zone within Finland (from south to north: HB= Hemi-Boreal; SB= South-Boreal; MB= Mid-Boreal; NB= North-Boreal).

File "Trap_Year_diversity.csv" contains the number of species, total abundance (i.e. total number of individuals) and dominance (i.e. number of individuals of the most abundant species) sampled in each Trap and Year.

File "Trap_stability_synchrony.csv" contains stability and synchrony values per Trap.

Funding

Jane and Aatos Erkko Foundation

Finnish Ministry of the Environment