Scaling the linkage between environmental niches and functional traits for improved spatial predictions of biological communities

Heidi K Mod,Tamara Münkemüller,Manuela D'Amen,Julien Pottier,Antoine Guisan,Jake M Alexander,Arndt Hampe,Daniel Scherrer

doi:10.1111/geb.12967

Abstract

AbstractIssueApproaches to predicting species assemblages through stacking individual niche‐based species distribution models (S‐SDMs) need to account for community processes other than abiotic filtering. Such constraints have been introduced by implementing ecological assembly rules (EARs) into S‐SDMs, and can be based on patterns of functional traits in communities. Despite being logically valid, this approach has led to a limited improvement in prediction, possibly because of mismatches between the scales of measurement of niche and trait data.EvidenceS‐SDM studies have often related single values of a species’ traits to environmental niches that are captured by abiotic conditions measured at a much finer spatial scale, without accounting for intraspecific trait variation along environmental gradients. Many pieces of evidence show that omitting intraspecific trait variation can hinder the proper inference of EARs from trait patterns, and we further argue that it can therefore also affect our capacity to spatially predict functional properties of communities. In addition, estimates of environmental niches and trait envelopes may vary depending on the scale at which environmental and trait measurements are made.ConclusionWe suggest that to overcome these limitations, surveys sampling both niche and trait measurements should be conducted at fine scales along wide environmental gradients, and integrated at the same scale to test and improve a new generation of spatial community models and their functional properties.

Highlights

We address two challenges related to such niche‐trait scale mismatches and the need to account for ITV when complementing niche‐based species distribution models (S‐SDMs) by trait‐based ecological assembly rules (EARs) (Figure 3): (a) deriving trait‐based EARs from field‐measured data on species’ occurrences and species’ traits within communities, accounting for ITV (Figure 3a); and (b) predicting trait distributions in space and along environmental gradients, and using these through the previously developed trait‐based EARs to constrain, and improve, the raw S‐SDM predictions of functional and structural properties of com‐ munities in space (Figure 3b)
To tackle these chal‐ lenges, we must: (a) collect fine‐scale data on species assemblages, species traits and abiotichabitat characteristics along key environmental gradients, and (b) harmonize scales between environmen‐ tal niche and trait measurements for subsequent analyses
We mainly discussed ITV as an evolutionary component of species that needs to be accounted for through new sampling strategies when analysing and predicting community pat‐ terns in space and time, ITV has an ecological component that can modulate population dynamics and buffer potential extinctions in the context of future climate or other environmen‐ tal change (Bolnick et al, 2011), and has implica‐ tions for predicting future community patterns, deserving future investigations

Summary

CONCEPT PAPER

Mod1 | Daniel Scherrer1,3 | Tamara Münkemüller4 | Julien Pottier5 | Jake M. Funding information FP7 People: Marie‐Curie Actions, Grant/ Award Number: 327987 (SESAM-ZOOL); H2020 European Research Council, Grant/ Award Number: 678841; Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Grant/ Award Number: 31003A-1528661 (SESAM’ALP) CR23I2-162754

Environmental conditions

Functional signatures of assembly rules