TY - JOUR

T1 - Developing robust field survey protocols in landscape ecology

T2 - a case study on birds, plants and butterflies

AU - Loos, Jacqueline

AU - Hanspach, Jan

AU - von Wehrden, Henrik

AU - Beldean, Monica

AU - Moga, Cosmin Ioan

AU - Fischer, Joern

N1 - Funding Information: The study was funded through a Sofja Kovalevskaja Award by the Alexander von Humboldt Foundation to Joern Fischer, financed by the German Ministry for Research and Education. We are grateful for help with fieldwork to Kimberlie Rawlings, Pascal Fust and Doreen Hoffmann. Levente Székely and Kuno Martini provided helpful information on local species. Izabela Hartel and Caroline Fernolend provided valuable logistical support. We thank Elise Zipkin for providing R and WinBUGS code and Marc Kéry for useful comments on the hierarchical models. We appreciate numerous discussions with Tibor Hartel. Thanks to Ine Dorresteijn and two anonymous reviewers for helpful comments on the manuscript. Publisher Copyright: © 2014, The Author(s).

PY - 2015/1

Y1 - 2015/1

N2 - Sustainable land management requires scientists to provide reliable data on diversity distribution patterns. Resource restrictions limit the affordable sampling effort, both with respect to number of survey sites and amount of effort per site. We compared different levels of survey effort in a case study in Central Romania, varying the number of repeats per site and number of survey sites. Target taxa were plants, birds and butterflies. For plants, we surveyed three 10 m2 plots and ten plots of 1 m2 at each site. For birds, we used point counts and for butterflies Pollard walks, in both cases with four repeats. We fitted hierarchical community models to estimate true species richness per site. Estimates of true species richness per site strongly correlated with observed species richness. However, hierarchical community models yielded unrealistically high estimates of true species richness per site, hence we used observed richness for further analyses. For each species group, we compared diversity indices from subsets of the dataset with the full dataset. Findings obtained with a reduced survey effort reflected well those obtained with full effort. Moreover, we conducted a power analysis to assess how the number of survey sites affected the minimum detectable effect of landscape heterogeneity on species richness, and found there was an exponential decrease in the minimum detectable effect with increasing number of sites. In combination, our findings suggest that assessing broad diversity patterns in abundant and readily detectable organisms may be possible with relatively low survey effort per site. Our study demonstrates the utility of conducting pilot studies prior to designing large-scale studies on diversity distribution patterns.

AB - Sustainable land management requires scientists to provide reliable data on diversity distribution patterns. Resource restrictions limit the affordable sampling effort, both with respect to number of survey sites and amount of effort per site. We compared different levels of survey effort in a case study in Central Romania, varying the number of repeats per site and number of survey sites. Target taxa were plants, birds and butterflies. For plants, we surveyed three 10 m2 plots and ten plots of 1 m2 at each site. For birds, we used point counts and for butterflies Pollard walks, in both cases with four repeats. We fitted hierarchical community models to estimate true species richness per site. Estimates of true species richness per site strongly correlated with observed species richness. However, hierarchical community models yielded unrealistically high estimates of true species richness per site, hence we used observed richness for further analyses. For each species group, we compared diversity indices from subsets of the dataset with the full dataset. Findings obtained with a reduced survey effort reflected well those obtained with full effort. Moreover, we conducted a power analysis to assess how the number of survey sites affected the minimum detectable effect of landscape heterogeneity on species richness, and found there was an exponential decrease in the minimum detectable effect with increasing number of sites. In combination, our findings suggest that assessing broad diversity patterns in abundant and readily detectable organisms may be possible with relatively low survey effort per site. Our study demonstrates the utility of conducting pilot studies prior to designing large-scale studies on diversity distribution patterns.

KW - Environmental planning

KW - Detectability

KW - Hierarchical model

KW - Landscape heterogeneity

KW - Species distribution

KW - Species richness

KW - Statistical power

KW - Study design

KW - Detectability

KW - Hierarchical model

KW - Landscape heterogeneity

KW - Species distribution

KW - Species richness

KW - Statistical power

KW - Study design

UR - http://www.scopus.com/inward/record.url?scp=85027921578&partnerID=8YFLogxK

U2 - 10.1007/s10531-014-0786-3

DO - 10.1007/s10531-014-0786-3

M3 - Journal articles

VL - 24

SP - 33

EP - 46

JO - Biodiversity and Conservation

JF - Biodiversity and Conservation

SN - 0960-3115

IS - 1

ER -