Complex long-term biodiversity change among invertebrates, bryophytes and lichens

Abstract

Large-scale biodiversity change is measured largely through the responses of a few taxonomic groups. Much less is known about the trends affecting most invertebrates and other neglected taxa, and it is unclear whether well-studied taxa, such as vertebrates, reflect changes in wider biodiversity. Here, we present and analyse trends in the UK distributions of over 5,000 species of invertebrates, bryophytes and lichens, measured as changes in occupancy. Our results reveal substantial variation in both the magnitude, direction and timing of change over the last forty-five years. Just one of the four major groups analysed, terrestrial non-insect invertebrates, exhibit the declining trend reported among vertebrates and butterflies. Both terrestrial insects and bryophytes & lichens increased in average occupancy. A striking pattern is found among freshwater species, which have undergone a strong recovery since the mid-nineties following two decades of decline. We show that, while average occupancy among most groups appears to have been stable or increasing, there has been substantial change in the relative commonness and rarity of individual species, indicating considerable turnover in community composition. Additionally, large numbers of species experienced substantial declines. Our results suggest a more complex pattern of biodiversity change in the UK than previously reported.

Worldwide occurrence records reflect a global decline in bee species richness

“…S3) are the ones showing the clearest 225 signal for decline (Fig. S4); our results agree with several existing reports at local, national 226 and subcontinental level 14,16,17,39,[56][57][58][59][60][61] . Furthermore, none of those biases can explain the noticeable phylogenetic contagion seen in the trends (Fig.…”

Winners and losers over 35 years of dragonfly and damselfly distributional change in Germany

“…Many studies on biodiversity change have focused on the simple long-term mean trend of a species but this approach can mask a diversity of more complex temporal responses (Outhwaite et al 2020). Indeed, recent analyses of invertebrate changes in the UK found both time-periods of increases and time-periods of decreases, which varied among taxa (Macgregor et al 2019;Outhwaite et al 2020). For instance, UK freshwater organisms decreased between 1970 and the mid-1990s but increased from then until 2010 (Outhwaite et al 2020).…”

“…Indeed, recent analyses of invertebrate changes in the UK found both time-periods of increases and time-periods of decreases, which varied among taxa (Macgregor et al 2019;Outhwaite et al 2020). For instance, UK freshwater organisms decreased between 1970 and the mid-1990s but increased from then until 2010 (Outhwaite et al 2020). Moreover, simple trend models can produce trend estimates driven by fluctuations in particular years (Seibold et al 2019).…”

“…We used occupancy-detection models that account for imperfect detection, which have been used in previous studies using opportunistic CS data (van Strien et al 2013;Outhwaite et al 2020) and tested in simulation studies (Isaac et al 2014). Imperfect detection occurs when a species inhabits a site but is not detected by the observer during a visit.…”

Changes in phenology and abundance of suction‐trapped Diptera from a farmland site in the UK over four decades

“…The analysis of long-term phenological and population data is valuable in understanding the effects of climate change on species assemblages (Renner & Zohner, 2018). For insects, such data are often only available for high-profile taxa (Saunders et al, 2020), and it has been shown that these are not always representative of other taxonomic groups (Bell et al, 2020;Outhwaite et al, 2020). Insects form a vital component of most terrestrial and freshwater ecosystems (Hershey et al, 2010;Mooney et al, 2010;Vidal & Murphy, 2019).…”