Presence-absence of marine macrozoobenthos does not generally predict abundance and biomass

Allert I Bijleveld,Anne Dekinga,Tanya J Compton,Sander Holthuijsen,Anita Koolhaas,Job Ten Horn,Jaap Van Der Meer,Henk W Van Der Veer,Lise Klunder

doi:10.1038/s41598-018-21285-1

Allert I Bijleveld, Anne Dekinga + Show 7 more

Open Access

https://doi.org/10.1038/s41598-018-21285-1

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Abstract

Many monitoring programmes of species abundance and biomass increasingly face financial pressures. Occupancy is often easier and cheaper to measure than abundance or biomass. We, therefore, explored whether measuring occupancy is a viable alternative to measuring abundance and biomass. Abundance- or biomass-occupancy relationships were studied for sixteen macrozoobenthos species collected across the entire Dutch Wadden Sea in eight consecutive summers. Because the form and strength of these relationships are scale-dependent, the analysis was completed at different spatiotemporal scales. Large differences in intercept and slope of abundance- or biomass-occupancy relationships were found. Abundance, not biomass, was generally positively correlated with occupancy. Only at the largest scale, seven species showed reasonably strong abundance-occupancy relationships with large coefficients of determination and small differences in observed and predicted values (RMSE). Otherwise, and at all the other scales, intraspecific abundance and biomass relationships were poor. Our results showed that there is no generic relationship between a species’ abundance or biomass and its occupancy. We discuss how ecological differences between species could cause such large variation in these relationships. Future technologies might allow estimating a species’ abundance or biomass directly from eDNA sampling data, but for now, we need to rely on traditional sampling technology.

Highlights

Most conservation efforts depend on monitoring different species to obtain estimates of spatial distributions and population sizes[1]
Positive interspecific abundance-occupancy relationships are reported for many different taxa at different spatial scales and in a wide variety of ecosystems[8,9,10,11,12]
Intraspecific spatial relationships are rarely studied and there is no agreement whether the shape of spatial intraspecific relationships should be positive[10]

Summary

Introduction

Most conservation efforts depend on monitoring different species to obtain estimates of spatial distributions and population sizes[1]. Because measures of occupancy are often much easier and cheaper to measure than abundance or biomass[5], the question arises whether occupancy is a reliable predictor of a species abundance or biomass, and whether occupancy sampling could reduce the cost of long-term monitoring programmes. Occupancy-abundance relationships are among the most widespread empirical patterns described in macroecological studies[6,7,8,9]. Abundance-occupancy relationships have been studied within species[18,19,20,21] Such intraspecific relationships are divided into temporal and spatial relationships. The intraspecific temporal relationship describes the correlation between abundance and occupancy of a single species across time. Compared to between-species abundance-occupancy relationships, there have been fewer studies on intraspecific relationships. The intraspecific spatial relationship describes the correlation between abundance and occupancy of a species at a single point in time across space. We analysed intraspecific abundance-occupancy relationships[8], called distribution-abundance relationships[10], for sixteen marine macrozoobenthos species that were collected across the Dutch Wadden Sea over a period of eight years[27,28]: the Species

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