Insights on plant interaction between dominating species from patterns of plant association: expected covariance of pin-point cover measurements of two species

TY - JOUR

T1 - Insights on plant interaction between dominating species from patterns of plant association: expected covariance of pin-point cover measurements of two species

AU - Damgaard, Christian Frølund

AU - Ehlers, Bodil

AU - Ransijn, Johannes C. G.

AU - Schmidt, Inger Kappel

AU - Svenning, Jens-Christian

PY - 2018

Y1 - 2018

N2 - It has been suggested that in order to infer ecological processes from observed patterns of species abundance we need to investigate the covariance in species abundance. Consequently, an expression for the expected covariance of pin-point cover measurements of two species is developed. By comparing the observed covariance with the expected covariance we get a new type of information on the spatial arrangement of two species. Here the discrepancy between the observed and expected covariance may be thought of as a measure of the spatial configuration of the two species that may indicate underling ecological processes. The method is applied in a case study of Calluna vulgaris and Deschampsia flexuosa on dry heathland sites. The observed covariance of Calluna and Deschampsia at the level of the sites was positively and significantly correlated with the expected covariance. Negative covariance was observed on sites where both Calluna and Deschampsia had a high cover, which is in agreement with the notion that both species form distinct patches. Oppositely, at sites where both species have a low cover, we found that both the expected and observed covariance were positive. The proposed measure for the expected covariance of two species does capture information on the combined spatial configuration of the two species if the species are common. We show how this may be relevant for understanding the underlying ecological processes leading to the observed covariance.

AB - It has been suggested that in order to infer ecological processes from observed patterns of species abundance we need to investigate the covariance in species abundance. Consequently, an expression for the expected covariance of pin-point cover measurements of two species is developed. By comparing the observed covariance with the expected covariance we get a new type of information on the spatial arrangement of two species. Here the discrepancy between the observed and expected covariance may be thought of as a measure of the spatial configuration of the two species that may indicate underling ecological processes. The method is applied in a case study of Calluna vulgaris and Deschampsia flexuosa on dry heathland sites. The observed covariance of Calluna and Deschampsia at the level of the sites was positively and significantly correlated with the expected covariance. Negative covariance was observed on sites where both Calluna and Deschampsia had a high cover, which is in agreement with the notion that both species form distinct patches. Oppositely, at sites where both species have a low cover, we found that both the expected and observed covariance were positive. The proposed measure for the expected covariance of two species does capture information on the combined spatial configuration of the two species if the species are common. We show how this may be relevant for understanding the underlying ecological processes leading to the observed covariance.

KW - Covariance

KW - Distribution of plant abundance

KW - Ecological processes

KW - Pin-point cover

KW - Plant associations

KW - Spatial dynamics

UR - http://www.scopus.com/inward/record.url?scp=85045067088&partnerID=8YFLogxK

U2 - 10.1007/s10651-018-0400-z

DO - 10.1007/s10651-018-0400-z

M3 - Journal article

SN - 1352-8505

VL - 25

SP - 221

EP - 235

JO - Environmental and Ecological Statistics

JF - Environmental and Ecological Statistics

IS - 2

ER -