Volumes 521–522, 15 July 2015, Pages 315–325
Quantification of potential exposure of gray partridge (Perdix perdix) to pesticide active substances in farmlands
- Under a Creative Commons license
Open Access
Highlights
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- 71% of clutches and 13% of coveys are exposed to active substances.
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- Partridge clutches/coveys are mostly exposed to 32/3 substances.
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- Fungicides (53%), herbicides (25%), and insecticides (16%) dominate.
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- Some substances have the potential to present a risk for bird reproduction.
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- Complex patterns of exposure emerge from bird habitat use and farming practices.
Abstract
Estimating
exposure of wild birds to plant protection products is of key
importance in the risk assessment process evaluating their harmful
potential.
In this paper, we propose an
ecologically-relevant methodology to estimate potential exposure to
active substances (ASs) of a farmland focal bird, the gray partridge Perdix perdix.
It is based on bird habitat use of fields at the time of pesticide
applications. It accounts for spatio-temporal heterogeneity at
population and landscape scales.
We identify and
quantify the potential exposure to 179 ASs of 140 clutches during
pre-laying, laying, and incubation phases, and of 75 coveys. The data
come from a large scale field study combining radiotelemetry and a
farmer survey. They were collected in 12 different representative sites.
The
proportion of clutches potentially exposed to a given chemical was ≥ 5%
for 32 ASs; prothioconazole and epoxiconazole ranking first. 71% of
clutches were potentially exposed to ≥ 1 AS and 67% to ≥ 2 ASs. Mixtures
involved 2 to 22 ASs. They emerged from commercial formulations, tank
mixtures, bird habitat use, and combinations. ASs were fungicides (53%),
herbicides (25%), and insecticides (16%) used on a variety of crops in
April–June, when ground-nesting birds are breeding. The European Food
Safety Authority conclusions report a long-term first-tier
toxicity-to-exposure ratio (TERlt) < 5 for 11 out of 19 documented ASs, and higher-tier TERlt < 5 for 5 out of 10 ASs. This suggests a potential risk for bird reproduction in farmlands.
Globally 13% of coveys were potentially exposed to 18 ASs during the first month (1–4 coveys per AS).
The use of our field data in future research and risk assessment is discussed.
Abbreviations
- AS, active substance;
- NO(A)EL, no observed (adverse) effect level;
- TERlt, long-term toxicity-to-exposure ratio
Keywords
- Farmland;
- Mixtures;
- Pesticide;
- Potential exposure;
- Reproduction;
- Wildlife
1. Introduction
Evaluation
of the reproductive risk of plant protection products (hereafter termed
“pesticides”) to wild birds is part of the requirements to register
active substances (ASs) (Regulation 2009/1107/EC). Risk assessment combines toxicity and exposure characterization, in the so-called “long-term toxicity-to-exposure ratio” (TERlt) (Crocker, 2005, European Food Safety Authority (EFSA), 2009, Hart and Thompson, 2005, Mineau, 2005 and Shore et al., 2005).
Toxicity estimates are the lowest no-observed-effect concentrations
from standard laboratory tests. Exposure is an estimated theoretical
exposure, calculated for different AS/crop and bird scenarios (EFSA, 2009).
Exposure is mainly based on diet, and modeled using AS application
rate, residue levels in food items and daily food intake rates. In the
first-tier assessment, exposure is estimated for a fictive species. A
series of refinements have been proposed in exposure calculations in
higher-tier assessment to gain ecological realism, including habitat
use, dietary composition, and other behavioral aspects (Crocker, 2005 and European Food Safety Authority (EFSA), 2009). A phase-specific reproductive assessment (Bennett et al., 2005 and Shore et al., 2005) is an additional refinement option recommended in a case-by-case approach (EFSA, 2009).
Indeed, the birds and their embryos may differ in their sensitivity to
ASs depending upon the phases of reproduction. Furthermore, only a
proportion of birds/embryos may be exposed. However, such realistic
calculation is data-intensive, needing spatio-temporal data both of bird
habitat use and pesticide use. This issue can be overcome by using
models (Roelofs et al., 2005).
This convenient tool, that can be applied to a series of
species/pesticides, requires, however, detailed data on pesticide use (USGS for United States; Engelman et al., 2012),
that may not be available depending upon the member states. It is of
key importance to identify and quantify exposure of some focal bird
species to pesticides. This provides post-authorization safety
information to assess population effects — which is challenging (Köhler and Triebskorn, 2013). This issue seems especially essential for bird conservation. Indeed some recent studies (Geiger et al., 2010, Gibbons et al., 2015, Hallmann et al., 2014 and Mineau and Whiteside, 2013) suggest that pesticide use would be more involved in the ongoing decline of farmland birds (PECBMS, 2014) than previously reported.
In
this context, we collected field data to identify and quantify the
potential exposure of farmland birds to ASs. Data were retrieved from a
large scale auto-ecological study on the gray partridge Perdix perdix ( Bro et al., 2013), with a focus on non intentional effects of pesticide use on mortality ( Millot et al., 2013 and Millot et al., in press)
and reproduction. The study was carried out in France in 12 sites
representing a range of environmental conditions in order to ensure a
robust data set.
The gray partridge is both a typical farmland bird (Aebischer and Kavanagh, 1997) and a representative focal species (Andrade et al., 2012, European Food Safety Authority (EFSA), 2009 and Petersen, 2013). Its numbers have dramatically declined during the XXth century (BirdLife International, 2013, Kuijper et al., 2009 and Pan-European Common Bird Monitoring Schemes (PECBMS), 2013). This species is highly exposed to pesticides. Birds forage in crops (Birkan and Jacob, 1988 and Green, 1984).
Adults have an opportunistic omnivorous diet. They feed on leaves,
buds, crop grains, weed seeds of wild and cultivated species and a
variety of invertebrates. Chicks feed almost exclusively on
invertebrates during their first two weeks of life (Bro and Ponce-Boutin, 2004, Green, 1984 and Potts, 2012). Three quarters of clutches are laid in crops, mainly in winter cereals but also in peas, sugar beets, potatoes or alfalfa (Bro et al., 2000 and Bro et al., 2013).
The
study was conducted in France, where agriculture is one of the most
intensive in Europe, both in terms of yields and tonnages of pesticides
used (FAOSTATS, 2014).
The annual production of wheat ranged between 35 and 40 million tons in
2010–2012, with mean yields ranging between 6.2 and 7.6 t/ha.
This
paper is the first of a series analyzing our field data in a
“step-stair” approach. It has two main objectives. First, propose a
field methodology, scientifically robust and ecologically relevant, to
better characterize bird exposure at the population level. The approach
combines (i) an intensive radiotracking survey of breeding females, (ii)
a farmer questionnaire to record pesticide use, and (iii) a
spatio-temporal analysis using a GIS to cross-check bird habitat use and
pesticide application. Second, quantify clutch and chick potential
exposure to a series of actual ASs. Correlations between exposure and
endpoints related to demographic parameters and egg characteristics will
be reported later, as well as modeling refinements.
