1. Biodiversity Trends Within the Holocene John Birks, Vivian Felde, and Alistair Seddon University of Bergen BO8031 Trondheim May 2016

2. ‘Anthropocene’ has suddenly become a buzzword in ecology and biogeography in the last few years, despite no clear definition for its lower boundary Recent publications on temporal trends of different units or interest in biodiversity across in the ‘Anthropocene’ Alien species Conservation Coral growth Temporal ecology Forestry Defaunation Plant biodiversity Island biogeography Archaeogenomics & ancient DNA Observational tech- niques for biodiversity Biological control Biodiversity changes Speciation ‘Anthropocene’ now well established in vocabulary and research agenda of ecologists, conservationists, and biogeographers even though there is no agreed definition. Band-wagon effect!

3. Already a review!

4. McGill et al. (2015) identify four measures of biodiversity, two trends, and four spatial scales Type of diversity Alpha (α) diversityThe number of taxa present in an assemblage (richness) α-diversity trendChanges in α-diversity through time Spatial beta (β) diversity Changes in assemblage composition across space (e.g. comparing dissimilarity between the composition of several assemblages for one time period) (compositional differentiation) Spatial β-diversity trend Changes in spatial β-diversity through time (e.g. decreases through time leading to biotic homogenisation (Sax and Gaines 2003) ) Temporal β-diversity Changes in assemblage composition through time, usually quantified as the dissimilarity between each time step (compositional turnover) BiomassA robust measure of abundance that is often correlated with various ecosystem functions

5. Spatial scale Global The entire planet within which extinction and speciation are the dominant processes Meta- community A scale that includes spatial heterogeneity and within which dispersal is the dominant ecological process LocalA scale that is dominated by interactions between taxa and by environmental constraints Also define a fourth spatial scale of organisation “biogeographical – a scale within which speciation and global extinctions are the dominant processes (Rosenweig 1995)” Do not see how this differs from global spatial scale or how to make it operational. Prefer the simple Sax and Gaines (2003) three spatial scales – global, regional, and local.

6. McGill et al. (2015) Four spatial scales, four aspects of biodiversity, 15 trends  hypothetical trend  evidence-based trend ? little or no evidence Suggest at meta-community (regional) scale increase in α -diversity (richness) and decrease in N or biomass in the ‘Anthropocene’

7. In McGill et al. (2015) and the other 13 papers on biodiversity and ecology in the ‘Anthropocene’ no mention of 1.The onset of the ‘Anthropocene’ - ?50, 100, 200, 500, 2000, or even the last 5000–7000 years (‘early Anthropocene’) 2.Biodiversity in the preceding Holocene Obvious questions that follow McGill et al. (2015) are What were the biodiversity trends in the Holocene? Are the ‘Anthropocene’ trends a continuation of trends in the Holocene and are they contingent on these trends or are they unique relative to Holocene trends?

8. Holocene Biodiversity Trends 1.Global scale – few data except for mammals, birds, and marine mega-fauna. Mainly human-induced extinctions 2.Meta-community (‘regional’) scale – pollen assemblages from lakes and bogs provide inferences about floristic and landscape richness and diversity 3.Local scale – less data available from local-scale pollen assemblages. Little change in biodiversity trends

9. To study modern pollen-floristic richness and diversity relationships today, need 1.high-quality modern pollen data from small lakes (top 1 cm sediment) 2.reliable modern vegetation data for the relevant pollen- source area for the lakes 3.detailed pollen-plant ‘translation tables’ where plant species are converted into their ‘pollen equivalents’ 4.quantification of the covariation between modern pollen and modern vegetation compositional data

10. Felde et al. 2016 Setesdal52 lakes10–1318 m elevation low-alpinenorthern-borealmiddle-boreal southern-boreal boreonemoralnemoral

11. Co-correspondence analysis (ter Braak & Schaffers 2004) Felde et al. (2014)

12. Modern pollen richness (Hill N0) and diversity (Hill N1, N2) are, in part, a function of contemporary floristic richness and diversity (  -diversity) (Felde et al. 2016) and of landscape mosaic structure (Matthias et al. 2015)

13. Which is the primary determinant – landscape mosaic structure, landscape and associated vegetation mosaic structure, vegetation richness? In other words, which comes first? (chicken or the egg?) Landscape alone Vegetation alone Landscape  Vegetation 

14. Alpha-diversity – rarefaction (analytical or repeated resampling) to estimate N0, N1, and N2 (Birks et al. 2016) Compositional turnover (temporal  -diversity) – rate- of-change or turnover metric (Birks 2007) Spatial  -diversity – diversity partitioning or spatio- temporal analysis of pollen assemblages (Blarquez et al. 2014) Biomass – pollen-accumulation rates in ‘well-behaved’ simple lakes approximate catchment biomass (Seppä et al. 2009)

15. Using 50+ pollen diagrams from Fennoscandia, Britain, and Ireland, can derive generalised trends for these four biodiversity components. However, Holocene is not ecologically uniform, so we have produced biodiversity trends for four phases (Iversen 1958; Birks 1986) Protocratic – early-Holocene forest development Mesocratic – mid-Holocene forest maximum Homo sapiens – human impact (on fertile soils) Oligocratic – acid heath and bog phase (on infertile soils)

16. Interglacial–glacial cycle (Iversen 1958; Birks 1986; Birks & Birks 2004)

17. Protocratic – diversity , biomass  Mesocratic – diversity –, biomass – Homo sapiens – diversity , biomass  Oligocratic – diversity , biomass  Last 200 years ‘Anthropocene’ – little change Birks et al. (2016)

18. In last 200 years in Homo sapiens phase sites, small decrease in  - and spatial  - diversity and biomass, and small increase in temporal  -diversity Oligocratic sites show little change in  - and temporal  -diversity, small decrease in spatial  -diversity, and slight rise in biomass (?N deposition)

19. Meta-community ‘regional’ scale Differences between palaeodata and McGill et al. (2015) for trends in  -diversity (richness) Palaeodata Homo sapiens OligocraticMcGill et al.  -diversity  –  Spatial  -diversity  (very small)  Temporal  -diversity  –? Biomass  (very small) 

20. See that at this regional scale, and sites on fertile soils in NW Europe, changes in last 200 years are not a simple continuation of trends initiated in the Homo sapiens phase. At oligocratic acid sites, recent trends in  - and  -diversity are primarily a continuation of trends started in the oligocratic phase, with the exception of small decrease in spatial  -diversity (‘biotic homogenisation’) and small increase in biomass.

21. Do not expect same biodiversity trends in the Holocene in, for example, central Europe, Alps, Mediterranean, the tropics, or North America – different modern biota and environments, Holocene biotic and vegetational histories, and environmental and ecological changes. Potentially interesting to explore Holocene and ‘Anthropocene’ trends in biodiversity in aquatic systems In terrestrial systems in NW Europe, main changes are in Homo sapiens or oligocratic phases. In aquatic systems, main changes are in the last 200 years (acid rain, cultural eutrophication, other forms of pollution).

22. Biodiversity trends in the Holocene and ‘Anthropocene’ relevant to discussions about planetary boundaries especially the Dearing et al. (2014) ‘safe’ and ‘just- operating’ spaces or boundaries for regional socio- ecological systems. Palaeoecological data can provide an evidence-base for defining environmental limits to ensure sustainability and human well-being at the regional or local scale. Encourage the increasing number of ecologists and biogeographers writing about ‘Anthropocene’ biodiversity to extend their time-scales to include trends in the Quaternary (Q-time). Biodiversity trends simply did not begin in the ‘Anthropocene’. Birks et al. 2016. The Holocene 10.1177/0959683615622568

23. Acknowledgements Hilary Birks Anne Bjune Thomas Giesecke John-Arvid Grytnes Cathy Jenks Triin Reitalu Willy Tinner Rick Battarbee