Amanda Cocquelet -Master

Table of contents

Introduction

Wild ungulate populations (cervidae and wild boar Sus Scrofa) have dramatically increased in North America and Western Europe during the past century. Many factors seem to be involved and include ongoing reforestation of past farmed areas, changes in agriculture and forestry practices, reduction of hunting pressure, extermination of natural predators, supplementary feeding of wild ungulates, and climate change [START_REF] Fuller | Ecological impacts of increasing numbers of deer in British woodland[END_REF][START_REF] Massei | The environmental impact of wild boar[END_REF][START_REF] Allombert | A natural experiment on the impact of overabundant deer on songbird populations[END_REF][START_REF] Morellet | Indicators of ecological change: new tools for managing populations of large herbivores[END_REF]. Additionally, ungulates have a high reproduction rate under favourable conditions [START_REF] Garrott | Overabundance: an issue for conservation biologists?[END_REF][START_REF] Massei | The environmental impact of wild boar[END_REF]. For instance, over the past 40 years in France, red deer population has experienced a 11-fold increase in numbers, with an average growth of 1 260 individuals per year, and wild boar population has experienced a 16-fold increase in numbers, with an average growth of 13 400 individuals per year (ONCFS 20141 ). This dramatic increase may have huge consequences on forest ecosystems.

Deer and wild boar are generally considered as keystone species in woodlands because they strongly interact with various ecological communities and over very large areas (Waller & Alverson, 1997). These large herbivores have strong impacts on vegetation communities by browsing the herbaceous and shrub layers [START_REF] Massei | The environmental impact of wild boar[END_REF]Boulanger et al., 2010) or by rooting the soil in the case of wild boar [START_REF] Howe | Forage relationships of European wild boar invading northern hardwood forest[END_REF]. All these direct interactions can limit forest regeneration [START_REF] Ballari | A review of wild boar Sus scrofa diet and factors affecting food selection in native and introduced ranges[END_REF][START_REF] Boulanger | Decreasing deer browsing pressure influenced understory vegetation dynamics over 30 years[END_REF], and alter plant species diversity [START_REF] Siemann | Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US[END_REF], tree seedling size [START_REF] Rooney | Factors affecting the regeneration of northern white cedar in lowland forests of the Upper Great Lakes region, USA[END_REF][START_REF] Mitchell | Ecological impacts of feral pig diggings in north Queensland rainforests[END_REF] and soil chemical composition [START_REF] Lacki | Effects of wild pigs on beech growth in Great Smoky Mountains National Park[END_REF]. These impacts on vegetation are known to have cascading effects on habitat quality and resources availability [START_REF] De Vries | Large herbivores and the design of large-scale nature reserves in western Europe[END_REF][START_REF] Rooney | Direct and indirect effects of white-tailed deer in forest ecosystems[END_REF], thus hampering the ability of other species to totally exploit their ecological niches [START_REF] Massei | The environmental impact of wild boar[END_REF]. For instance, changes in plant assemblages can affect insect species diversity, as they are strongly dependent [START_REF] Haddad | Contrasting effects of plant richness and composition on insect communities: a field experiment[END_REF]. Otherwise, competition occurs when ungulates share a common food resource with other animals either herbivores (Alverson & Waller, 1997), frugivores [START_REF] Sargent | Neighborhood effects on fruit removal by birds: a field experiment with Viburnum dentatum (Caprifoliaceae)[END_REF] or pollinators [START_REF] Balgooyen | The use of Clintonia borealis and other indicators to gauge impacts of white-tailed deer on plant communities in northern Wisconsins, USA[END_REF]. Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Woodland birds can be affected by cascading effects resulting from these changes to vegetation structure, or from the availability of invertebrates [START_REF] Fuller | Responses of woodland birds to increasing numbers of deer: a review of evidence and mechanisms[END_REF][START_REF] Allombert | A natural experiment on the impact of overabundant deer on songbird populations[END_REF]. Some authors consider the current increase in ungulate populations as a strong driver of changes in forest bird communities, especially if we consider understory-dependent species [START_REF] Schley | Diet of wild boar Sus scrofa in Western Europe, with particular reference to consumption of agricultural crops[END_REF][START_REF] Holt | Exclusion of deer affects responses of birds to woodland regeneration in winter and summer[END_REF]. Indeed studies have shown that species nesting and/or foraging in ground or in low shrubs are significantly less abundant in browsed areas [START_REF] Fuller | Responses of woodland birds to increasing numbers of deer: a review of evidence and mechanisms[END_REF][START_REF] Vanhinsbergh | A review of possible causes of recent changes in populations of woodland birds in Britain[END_REF]. Moreover, [START_REF] Bressette | Beyond the browse line: complex cascade effects mediated by white-tailed deer[END_REF] have observed deer cascading effects on both low-nesting birds due to the modification of understory structure, and insectivorous birds because of the decrease in food availability. However a recent study in France has shown no influence of ungulate abundances on low-nesting bird densities [START_REF] Baltzinger | Overabundant ungulates in French Sologne? Increasing red deer and wild boar pressure may not threaten woodland birds in mature forest stands[END_REF] questioning the generality of the negative impact of large ungulates on forest songbirds. Similarly, [START_REF] Fuller | Responses of woodland birds to increasing numbers of deer: a review of evidence and mechanisms[END_REF] demonstrated that the ground-nesting wood warbler (Phylloscopus sibilatrix) in England was counterintuitively more abundant in intensively browsed areas. [START_REF] Baltzinger | Overabundant ungulates in French Sologne? Increasing red deer and wild boar pressure may not threaten woodland birds in mature forest stands[END_REF] proposed one alternative explanation to the idea of a lack of negative impact of ungulates on forest birds: browsed areas may actually represent ecological traps for these birds due to increased nest predation directly or indirectly caused by large ungulates but birds may not be able to perceive this predation risk when nesting.

Predation is reported to be the main cause of nest failures among songbirds and so the most important factors influencing avian productivity [START_REF] Schaefer | Video monitoring of shrub-nests reveals nest predators[END_REF]. Two kinds of predation may be considered on songbird nests: direct and indirect predation, depending on the way predators affect bird nest.

Direct predation corresponds to the direct eating of eggs or fledglings in nest by the predator. Several studies have shown white-tailed deer (Odocoileus virginianus) predation on eggs in grassland [START_REF] Sealy | Observed acts of egg destruction, egg removal, and predation on nests of passerine birds at Delta Marsh, Manitoba. Canadian field-naturalist[END_REF][START_REF] Pietz | White-tailed deer (Odocoileus virginianus) predation on grassland songbird nestlings[END_REF] and red deer predation on seabird's fledglings [START_REF] Furness | Predation on ground-nesting seabirds by island populations of red deer Cervus elaphus and sheep Ovis[END_REF]. However the relative importance of deer predation compared to other nest predators is badly documented. Wild boar is also known to predate songbird's eggs and nestlings. A study carried out in Slovakia, has shown that 9% of the nest predation was related to wild boar, leading to local extinction of some woodland ground-nesting species like Tetrastes bonasia, Caprimulgus europaeus, Scolopax rusticola (Saniga 2003). In Germany a video-monitoring study on blackcap (Sylvia atricapilla) nests has also identified wild boar among other nest predators [START_REF] Schaefer | Video monitoring of shrub-nests reveals nest predators[END_REF]). However, it is difficult to quantify the Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 part of eggs in wild boar diet because egg shells are not easily detected in stomachs, intestines and faeces [START_REF] Schley | Diet of wild boar Sus scrofa in Western Europe, with particular reference to consumption of agricultural crops[END_REF]. Indirect effects emerge when the impact of one species on another is influenced by one or more intermediate species [START_REF] Abrams | Dynamics and interactions in food webs with adaptive foragers[END_REF]. Ungulates may be involved in two kinds of indirect effects increasing predation risk for birds. First ungulates can attract other nest predators. [START_REF] Kilham | Cleaning/feeding symbioses of Common Crows with cattle and feral hogs[END_REF] reported observations of grooming relationships between wild boar and common crows (Corvus brachyrhynchos), one of the well-known avian predator of birds' eggs. Predators can also be attracted because of environmental perturbations induced by ungulates. For instance, a study has demonstrated a link between white-tailed deer and squirrel (Sciurus sp.). By feeding on oak acorn, white-tailed deer constrains squirrels and other frugivores to forage other resources, and notably leading to an increase in bird nest predation by squirrels [START_REF] Ostfeld | Of mice and mast: ecological connections in eastern deciduous forests[END_REF]. If this kind of example is often mentioned in literature for deer, the role of wild boar in such interspecific effects has rarely been studied.

Indirect predation can also arise when modification in food supplies or habitat structure increase the likelihood of woodland bird populations being exposed to predation [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF][START_REF] Newton | Population limitation in birds[END_REF]. A study in lowland England has shown a large-scale impact on the number of woodland bird species associated with understorey habitats [START_REF] Newson | Modelling large-scale relationships between changes in woodland deer and bird populations[END_REF]. As already mentioned, ungulates have strong impacts on vegetation.

Modifications in habitat may induce both intra-and inter-specific competition. To avoid this phenomenon, birds may be forced to exploit different micro-habitats and micro-niches for nesting or feeding sites where they are possibly more vulnerable [START_REF] Martin | Coexistence in Mediterranean warblers: ecological differences or interspecific territoriality?[END_REF][START_REF] Vanhinsbergh | A review of possible causes of recent changes in populations of woodland birds in Britain[END_REF]. Moreover, we can imagine that the reduction in shrub or forb layer caused by grazing herbivores may decrease the amount of nest cover for some species and increase their vulnerability to predators (Vanhingsbergh, 2003). Indeed, nesting site and nest shape can have an influence on predation risk. Many studies have long demonstrated that ground-nesting birds suffer greater predation than off-ground-nesting birds [START_REF] Slagsvold | Clutch size variation in passerine birds: the nest predation hypothesis[END_REF]Collias & Collias 1984). But this statement is not supported by other studies which have demonstrated the opposite [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF][START_REF] Martin | Breeding productivity considerations: What are the appropriate habitat features for management?[END_REF]. Otherwise, Møller (1989) has shown that nest shape has a strong effect on predation risk: open nests experiencing higher predation rates than nests partially covered by vegetation.

Few studies so far have investigated the potential effects of ungulate density on nest predation of low-nesting birds and bird communities in forest ecosystems. We investigated Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016Monnet - /2017 this through 4 questions: (1) how predation is influenced by the abundance of ungulates, (2) how the predator community (mammal and avian) was related to ungulates abundance, (3) what is the consequence of ungulates abundance and predation rate on bird communities, and

(4) what are variables explaining nest predation. In order to test the impact of red deer and wild boar on nest predation and bird communities, artificial nests were set both in fenced plots excluding ungulates and in unfenced plots, a classical experimental device to study how ungulates impact ecosystems [START_REF] Holt | Breeding and post-breeding responses of woodland birds to modification of habitat structure by deer[END_REF][START_REF] Holt | Exclusion of deer affects responses of birds to woodland regeneration in winter and summer[END_REF][START_REF] Baltzinger | Overabundant ungulates in French Sologne? Increasing red deer and wild boar pressure may not threaten woodland birds in mature forest stands[END_REF]. We selected deciduous, coniferous and mixed stands in two sites and constituted 22 pairs of fenced and unfenced plots where we carried out bird point counts and disposed 528 artificial nests with quail eggs. One part of these artificial nests was monitored with camera traps to identify predators and assess the frequentation of ungulates and other potential predators in each plot.

We first expected nest predation rate to be more important in unfenced where abundance of wild boar and deer is higher. Secondly, we expected a greater abundance of other potential predators (mammal and avian) in unfences. And finally, we assumed that both abundance and richness of the understory-dependent bird species were depleted by the local abundance of predators and in particular ungulates.

Materials and Methods

Study area

The two study sites were located in the Orléans national forest (48° 00′ 28″ N, 2° 09′ 39″E) in Loiret department (45), and in the national estate of Chambord (47° 36′ 59″ N, 1° 31′ 01″ E) in the department of in France. These two forests support populations of wild boar (Sus scrofa) and red deer (Cervus elaphus), as well as roe deer (Capreolus capreolus) and a small population of mouflon (Ovis orientalis) in Chambord. Installation of 2-m high fenced enclosures in these two areas has permitted to exclude (or at least to limit the number of) large ungulates but not others potentials predators such as birds or mustelids (10 cm-x-10cm mesh). In both sites, the sampling has been done by pairing fenced and unfenced plots, in forest stands with tree density and composition as similar as possible. Three types of forest stands have been chosen for this study: (i) oak regular high forests (or in conversion from coppice-with-standards to the regular high forest system) composed of pedunculate (Quercus robur) and sessile oaks (Q. petraea); (ii) pine regular high forests composed of Scots (Pinus sylvestris) or Laricio pines (P. nigra subsp. laricio); (iii) mixed oak-pine high forests. Understory was mostly constituted of bracken fern (Pteridium aquilinum), purple moor-grass (Molinia caerulea), common heather (Calluna vulgaris), associated with acidophilic species due to waterlogged winter conditions.

In 2016, four fenced/unfenced pairs had been set up (a total of 8 plots) in the national estate of Chambord only, one pair in oak high forests, and three pairs in pine high forests. In 2017, the study was extended to the Orléans forest and in each site, 9 pairs have been established (a total of 18 plots) with 3 replicates in each different forest stands presented above. For more information about each study site see Table 1. in annexes.

The two sites differed in several aspects. In the Orléans forest, we benefitted from stands whose tree composition and density are experimentally controlled and where all fenced and unfenced plots are 0.5ha in area. Enclosed plots are free of ungulate. In Chambord, enclosures are set up over much larger area (1 to 40 ha) during forest stands regeneration, in order to exclude a maximum number of large herbivores. In that case, a few ungulates may still be present in the enclosures, especially roe deer but also wild boar. We established our fenced plots in these enclosures by delimiting an area of 50 meters of radius. Finally, in order to maintain Chambord's hunting reputation, ungulates populations are kept at a high density level in unfenced areas. In comparison, the ungulate density in the forest of Orléans is much lower to allow a balance with sylviculture activities.

Experimental design

Artificial nests

Ungulates in forests are expected to impact most woodland ground nesting birds like Phylloscopus warblers and tree pipit (Anthus trivialis), and birds nesting in shrub layers like Sylvia warblers, Eurasian wren (Troglodytes troglodytes), European robin (Erithacus rubecula) and the Common nightingale (Luscinia megarhynchos) [START_REF] Géroudet | Les passereaux d'Europe : Des Coucous aux merles[END_REF][START_REF] Géroudet | Les passereaux d'Europe : De la Bouscarle aux Bruants[END_REF].These species build either opened nests with a bowl shape (Warblers), or closed nests (Eurasian wren) with a spherical shapefor the others species - [START_REF] Géroudet | Les passereaux d'Europe : Des Coucous aux merles[END_REF][START_REF] Géroudet | Les passereaux d'Europe : De la Bouscarle aux Bruants[END_REF]. In order to represent these different nestling strategies (height of support and shape of nest), artificial 7-cm-diameter nests made of coco fibres and baited with two fresh Japanese quail eggs (Coturnix japonica) have been set up on each plots according to four modalities: (1) ground open-nest, ( 2) shrub open-nest, (3) ground close-nest, and (4) shrub close-nest, each modality being replicated 3 times in a plot. The "shrub-nests" have been installed between 25 and 50 cm aboveground. Otherwise, to respect natural hidden place used by woodland birds to build their nest [START_REF] Géroudet | Les passereaux d'Europe : Des Coucous aux merles[END_REF][START_REF] Géroudet | Les passereaux d'Europe : De la Bouscarle aux Bruants[END_REF], BWPi 2.0.2 2 ), we concealed our nest Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 either within the vegetation (Molinia caerulea, Rubus fruticosus and other shrubs), or in dead wood trunksand tree stumps.

Exposition to predation

Our experiment was carried out in 2016 and 2017 in Chambord forest and only in 2017 in Orléans forest. In 2016, artificial nests were exposed to predation during two successive 2-week periods in Chambord during the main bird breeding period from middle of April to middle of June [START_REF] Géroudet | Les passereaux d'Europe : Des Coucous aux merles[END_REF][START_REF] Géroudet | Les passereaux d'Europe : De la Bouscarle aux Bruants[END_REF]. Eggs were replaced after two weeks without changing the location of the nests, being predated or not during the first period. However, this first year of experimentation showed that nest predated during the first period tended to suffer a higher risk of predation during the second period in comparison with nests not predated during the first period, suggesting a memory effect of predators. To avoid this undesired side effect, in 2017 artificial nests were exposed to predation during a single two-week period of exposure in both forests. The average distance between nests was 14.7±3.5m in Orléans, and 16.7±4.2m in Chambord. Nests were placed so that neighbouring nests either differed in their vertical position or in their shape. (Table 1. in annexes).

In order to limit observer disturbance potentially providing sensitive cues for predators about nest location, all nests were checked only once and 14 days after set up. We noted for each nest the number of missing eggs, the state of remaining ones and the nest state. A nest has been considered as predated when it was missing, destroyed or clearly actively displaced from its original place, and/or when at least one egg was missing or damaged.

Camera traps

To identify nests predators and to estimate animal frequentation on each study plot during the exposition period, part of the nests were equipped with camera traps (24 Primos® Hunting, Primos Proof Cam, and model no.63056 used in Chambord in 2016 and 2017 and in Orléans in 2017 and 12 Moultrie®, GameSpy model M-80XT used in 2017 in Orléans; see Table 1 in annexes). Cameras were programmed to take sequences of three pictures separated by one second of moving animals. For each sequence, we identified the species and its abundance. All sequences within 15 min from each others were considered as a single sequence referring to the same animal (or group of animals). A calculation of the maximum of animals recorded among the sequences allowed us to estimate the abundance of each animal species during the two weeks of active camera traps. From these species abundance values per camera, we derived abundance and species richness indices at the plot scale (Table 2. in annexes). We distinguished different classes of predators: ungulates predators (wild boar and Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 red deer), mammal predators (red fox, european badger, european wildcat, hedgehog and marten), and avian predator (great spotted woodpecker, jay, and carrion crow). Wild boar and red deer were considered separately in order to analyze their respective effect. Marten was also considered separately because it was an identified predator of our nest and so we wanted to analyze its proper effect. As Red fox, European badger, European wildcat, and Hedgehog were not clearly identified as predators of our nests, we considered them together to improve statistical power. Birds (Great spotted woodpecker, Jay, and Carrion crow) were also observed as predators of our nests, and again we combined them to reinforce statistical power.

Vegetation survey

On each plot, vegetation structure was described in three (in 2016) or four (in 2017) cardinal directions 20m away from the plot center by taking the following measures: (1) basal area of deciduous and coniferous trees using a relascope,, (2) bare ground cover including intact tree litter and bryophytes, (3) bare ground cover due to wild boar rooting, (4) cover of the herbaceous layer (all species below 50cm in height) and ( 5) cover of the shrub layer (vegetation between 50cm and 2m in height). All cover measurements were visually estimated (in percentage) in a radius of 3.57m (sub-plot of 40m²) (Table 2. in annexes).

Birds surveys

Bird abundance was estimated from 10-min point counts repeated twice during the breeding season (10 th May to 24 th May in 2016, 26 th April to 9 th June in 2017), and during the four first hours after sunrise in calm weather conditions. Bird distance to plot center was measured with a laser telemeter to nearest meter and only birds within 50m from the center were kept to define bird species abundance and richness. In addition, we considered the presence with no limitation of distance of well-known egg avian predators, Eurasian jay (Garrulus glandarius), crow (Corvus corone) and great-spotted woodpeckers (Dendrocopos major) [START_REF] Cramp | Birds of the Western Palearctic[END_REF][START_REF] Baillie | Breeding Birds in the Wider Countryside: their conservation status 2001[END_REF][START_REF] Weidinger | Nest predators of woodland open-nesting songbirds in central Europe[END_REF]. We classified all recorded species according to the main nesting and foraging layers (ground/shrub versus canopy) following [START_REF] Baltzinger | Overabundant ungulates in French Sologne? Increasing red deer and wild boar pressure may not threaten woodland birds in mature forest stands[END_REF] and BWPi 2.0.23 (Table 3. in annexes). For analyses, we only calculated the abundance for all species without distinction, for "ground" and "shrub" nesting birds, and for "ground" and "ground/foliage" foraging birds. Species richness indices were also estimated at the plot scale (see Table 2. in annexes for details on bird variables) for all species taken together and for each foraging and nesting guild. Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Data analysis

According to our four hypotheses, we have defined three classes of variables for our analyses: predator communities (assessed from camera traps' surveys), bird communities (composed of variables from bird surveys), and vegetation structure (composed of variables from vegetation surveys). A total of 25 variables have been calculated and used as explained or explanatory variables depending on the ecological significance of the modelling approach (Table.2 in Annexes). To account for our sampling design characteristics, we fitted mixed models to be able to include nested "geographical" effects (nest/plot/pair/forest site). The "temporal" effects with "year" (2016 or 2017) and "period" (as nest exposures occurred at three different periods from April to June and as in 2016 the same nests were exposed to predation during two periods) have been fitted as fixed effects. According to the type of variable and its distribution, we used either linear mixed models in case of Gaussian distribution, or generalized linear mixed effect models (GLMM) for either binomial (predation rate, vegetation cover) or Poisson (abundance and richness) distributions using the glmer() function of the R lme4 package (R Development Core Team-3.4.0). In order to correct the abundance of predators at plot scale by the number of camera set up on each plot, the glmer() function's argument offset() with the log(camera number). For each variable that had to be explained, most influential explanatory variables were identified using a forward variable-selection approach based on Akaike information criterion corrected for small sample size (AICc). Closely related variables (eg abundance/richness of predators) were never put simultaneously in the same model. Error risk α is always determined at 0.05%. Throughout the rest of this report, results are always presented as mean ± standard error. Data analysis primarily aimed at identifying effect of ungulate density on nest predation and bird communities. From this standpoint, we investigated (1) how predation was influenced by fencing and ungulate abundance, (2) how predator community (mammal and avian) was related to fencing or ungulate abundance, (3) how the bird communities were related to predation risk, predator abundances, vegetation features, fencing and study site (4) which variables explained spatio-temporal variation in nest predation rate among those related to plot type (fenced/unfenced), ungulates and other egg predators, bird communities and plot vegetal features.

Throughout the rest of the document, final models in terms of selected variables and their results are detailed in annexes in R language. Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Results

Effect of fencing on predation

Density of ungulate being controlled by fencing, we tested predation according to type of plot (Fig. 1). Predation is significantly higher in unfences than within fences with a predation rate of 0.39 and 0.32 respectively (linear mixed effect models: coefficient = 0.6225±0.3047, p-value = 0.041). Moreover, a pair effect is observed, with an increase of predation within fences when predation in unfences is high .We noticed a site effect with a dramatic increase of predation in Chambord compared to Orléans in 2017 with a predation rate of 0.08 and 0.55 respectively. Finally, the period when nests are exposed has a significant effect on predation rate. In Chambord 2016, the same nests were exposed twice during 2 successive periods of 2 weeks on the same plot (without relocation). Predation rate has increased of 31% between these two successive periods of exposition (linear mixed effect models: coefficient =2.3522, ±0.8805, p-value = 0.008) (Fig. 2).

Effect of fencing on nest predator abundances

Nest predator abundances have been explained according to fencing and study site (Table 1.).

Table. 1. Variation of predator abundance between study sites and fencing. Total abundance is calculated at the plot scale. Comparison of species abundances between study sites (Chambord and Orléans

) and between fences and unfences, and interaction between study site and fencing is obtained from generalized linear mixed effect models, , with a year fixed effect, and a geographical (Site-Pairs-Plot), a random effects. Abundance of all predators taken together is significantly higher in unfences with 5.2 times predators in unfenced plots. Ungulates were more abundant in unfences as abundance wild boar is significantly higher outside fences (7.5 times more than within) and as red deer is totally absent within fences. The abundance of neither mammal predators nor avian predator differs according to fencing.

Fencing effect

A huge site effect has been observed previously (Fig. 1.), thus we tested whether predator abundance according to study site. Abundance of all predators taken together is significantly higher in Chambord with 5.6 times predators in Chambord with a predation rate significantly higher in this site with 6.9 times more predation. Nevertheless, in predators taken separately, only wild boar was significantly higher in Chambord with 8.7 times wild boar in Chambord. Red deer is completely absent in Orléans.

No significant interaction has significantly observed, it means that fencing difference of predator abundance in Chambord isn't significantly different to the fencing difference of predator abundance in Orléans.

Finally, no predator abundance (mammal and avian) were significantly related to ungulates abundance. Forty one bird species were recorded during 52 point counts made during two breeding season on the 44 studied plots with an average of 5.9±2.9 birds recorded per plot. Their relation with fencing design and study site has been analyzed (Table .3). Bird species richness and abundance (and similarly for guilds) did not differ according to fencing but were higher in Chambord compared to Orléans (1.7time abundant, 1.8time richness). Abundance of corvids and woodpeckers is significantly higher in Chambord with 1.04 times corvids and woodpeckers. There was no significant interaction between site and fencing design. Finally no variable related to predation risk, predator abundances, and vegetation features explained significantly bird communities.

Effect of fencing on bird communities

Nest predation risk

A total of 528 nests have been set up during the two years of experiment. 35% (n=188)

have been predated, 64% (n = 339) have not been predated and a single nest was not relocated. Fourteen percent of the nests were monitored by camera traps (n = 77), allowing to clearly identify nest predator in 5 cases (6%) and to suggest predator identity in 21 cases (27%) (Table 2.). Four predators have been clearly identified, an egg in the mouth. In 21 cases, the act of predation was not captured by the camera traps, but pictures of predators in the vicinity of the nest allowed us to suspect some animal species. In the last 51 cases, either predator has not been identified or nest was not predated. with shrub nests significantly more predated than ground nests (41% and 31% respectively), and shrub cover (linear mixed effect models: coefficient = -0.07867, se = 0.03373, p-value = 0.01970) with a significant decrease of predation when shrub cover increases (Fig. 3). Neither variables related to bird communities nor to ungulate or other predator abundances explained predation. Moreover, and contrary to our expectation, the fencing effect was not retained in the final model. In order to check a possible correlation between fencing and shrub cover we have tested whether fencing explained shrub cover. Shrub cover appears significantly higher in fenced plots (linear mixed effect models: coefficient = -0.2970, se = 0.1129, p-value = 0.009) (Fig. 4).

-0 0-7 0-7 Marten 0-1 4-5 4-6 Carrion Crow 0-1 0-0 0-1 Jay 2-0 1-1 3-1 Great spotted woodpecker 0-1 1-2 1-3 Total 2-3 6-
Some wild boars have been enclosed in 3 fences in Chambord (13% of the total of pairs, one in 2016 and two others in 2017) (Table .1). In order to test possible impact of these pairs on predation rate, we removed them from the modelling approach. The results then revealed no significant differences within fences and outside fences (linear mixed effect models: coefficient = 0.5054, ±0.3433, p-value = 0.14).

Otherwise, in both sites the sampling has been done by pairing fenced and unfenced plots, in forest stands with tree density and composition as similar as possible. However we have observed four pairs (including one pair with wild boars enclosed) with a deviation of 30% in the basal area within fences and unfences (7.81 ± 2.05 m²/ha and 21.09 ± 5.43 m²/ha respectively). To test for possible effect of these pairs on predation rate, we removed them and those with fenced wild boars in our modelling approach. The results showed no significant differences within fences and unfences outside fences (linear mixed effect models: coefficient = 0.3270, ± = 0.4148, p-value = 0.43).

Discussion

Our study investigated the potential effects of ungulates on predation of woodland songbird nests using artificial nests in fences (absence of ungulates) and unfences (presence of ungulates). Our results indicated strong spatial and temporal variation in predation rates.

Predation risk depended on nest height and shrub cover but we failed to demonstrate any link with ungulate abundances, nor with of other predators.

Nest predation risk related to fences

Coherent with the higher abundance of ungulates and other predators in unfences, predation rate was also significantly higher in unfences but the difference was much lower than expected. While abundance of ungulates and of most predators was several times higher in unfences, the predation rate was only 7% higher in unfences. Furthermore, we cannot exclude that this difference in predation rate may not be mainly due to sampling defaults.

When these defaults were taken into account (presence of wild boars in some fences, marked stand differences between some paired fence/unfence), the difference in predation between fences and unfences became marginal. This idea was reinforced by our variable selection approach with the best model which not includes ungulate abundance variables. These results

Fences

Unfences Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 question our first hypothesis and thus the nest predation threat associated with ungulates density that has been expected.

Otherwise, type of plot wasn't selected as an explanatory variable of the predation.

Shrub cover was negatively correlated to the predation rate and was significantly correlated with type of plot. We are not able here to discern respective effects of shrub cover and type of plot. After exclusion of pairs presenting big deviation in stands compositions between fences and unfences, our analysis haven't shown anymore difference in predation rate between fences and unfences, contrarily that was expected. These defaulted pairs were associated with a high rate of predation: average of predation rate with all pairs taken is 0.36±0.48, whereas the average without defaulted pairs is 0.29±0.45. It seems that the similarity in stand features in pairs is important to control in experimental design. Otherwise, neither ungulates abundance nor predators abundance (mammal and avian) seem to impact risk of predation on contrary to what was expected.

Over the two study years and sites, the nest predation rate of 528 nests monitored during two weeks was 35.6%. Predation rates are often difficult to compare between studies because they are measured among different experimental conditions and over different periods of exposure [START_REF] Major | The contribution of artificial nest experiments to understanding avian reproductive success: a review of methods and conclusions[END_REF]. However, in this latter review, authors have standardized measures of reproductive success by calculating a daily survival probability for all studies providing comparative data. Then they estimated the average nesting predation over a generalized 14-day incubation period which was about 59% for artificial nests.

Deviation of our results from this estimation is not that surprising as we observed strong difference in predation rate between sites, among plot, between year and even within season.

Several studies have also reported much variable nest predation rates among study forest sites [START_REF] Møller | Nest predation and nest site choice in passerine birds in habitat patches of different size: a study of magpies and blackbirds[END_REF]Burk et al., 2004). Burk et al. (2004) suggested that this spatial heterogeneity reflected a difference in predator assemblages and their relative effects on bird species. This idea seems to be consistent with the difference observed in the total predator abundance between our study sites, with 5.6 times predators in Chambord compared to Orléans. Future analyses of predation rate may be considered at a forest scale. We expected ungulates and wild boar in particular to predate eggs. Indeed, wild boar has already been identified as a bird nest predators in several studies [START_REF] Saniga | Nest loss and chick mortality in capercaillie (Tetrao urogallus) and hazel grouse (Bonasa bonasia) in West Carpathians[END_REF][START_REF] Schaefer | Video monitoring of shrub-nests reveals nest predators[END_REF], and deer has been observed ingesting eggs or fledglings during browsing [START_REF] Sealy | Observed acts of egg destruction, egg removal, and predation on nests of passerine birds at Delta Marsh, Manitoba. Canadian field-naturalist[END_REF][START_REF] Pietz | White-tailed deer (Odocoileus virginianus) predation on grassland songbird nestlings[END_REF][START_REF] Furness | Predation on ground-nesting seabirds by island populations of red deer Cervus elaphus and sheep Ovis[END_REF]. However, relative importance of wild boar and deer in nest predation compare to other predators (like marten, avian predators, rodents or fox) isn't clear in literature [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF][START_REF] Saniga | Nest loss and chick mortality in capercaillie (Tetrao urogallus) and hazel grouse (Bonasa bonasia) in West Carpathians[END_REF][START_REF] Vanhinsbergh | A review of possible causes of recent changes in populations of woodland birds in Britain[END_REF][START_REF] Schaefer | Video monitoring of shrub-nests reveals nest predators[END_REF]. Our camera traps did not document any direct wild boar or deer predation, although an extension of our experimental design (not presented here ) allowed us to detect one case of red deer ingestion of two quail eggs. However, our camera traps unfortunately helped rarely revealing predator's identity (only in 6% of the cases). Therefore, we cannot estimate properly the relative contribution of all potential egg predators to nest predation, including ungulates.

Deer diet essentially comprises plant species [START_REF] Groot Bruinderink | Ingestion and diet composition of red deer (Cervus elaphus L.) in the Netherlands from 1954 till 1992[END_REF][START_REF] Gebert | Variations of diet composition of red deer (Cervus elaphus L.) in Europe[END_REF], which may lead to think that egg or fledgling ingestions in deer is mainly accidental. Concerning wild boar diet, Schley & Roper reported in their review (2003) that occurrence of vegetables in stomach is about 99% to 100% and animal items range from 47% to 88% according to the study. In this latter category, invertebrates and small rodents are the commonest. Unfortunately the part of eggs in wild boar diet is very difficult to quantify as egg shells are not easily detected in stomachs, intestines and faeces [START_REF] Schley | Diet of wild boar Sus scrofa in Western Europe, with particular reference to consumption of agricultural crops[END_REF].

Indirect impact: attraction of other predators

Camera traps revealed the presence of well-known nest predators in our study site [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF][START_REF] Vanhinsbergh | A review of possible causes of recent changes in populations of woodland birds in Britain[END_REF][START_REF] Schaefer | Video monitoring of shrub-nests reveals nest predators[END_REF]. As expected, abundance of ungulates was much higher in unfences than in fences. Among other predators, only

Marten and avian predators (corvids and great-spotted woodpecker) were apparently as abundant within fences that in unfences, whereas we expected greater abundance of mammal and avian predators in unfences, where ungulate abundance is higher (2 nd Hypothesis).

According to this result we may suspect marten and avian as the main predators in fences. We also suspected that a number of nest predators may be attracted by the presence of ungulates benefiting from their soil and ground vegetation disturbances. Indeed functional links between ungulates and other predators have already been evidenced by several studies.

For instance, common crow seems to have established a symbiosis relationship with wild boar through grooming behavior [START_REF] Kilham | Cleaning/feeding symbioses of Common Crows with cattle and feral hogs[END_REF]. Ecological links between habitat quality, predator density and intensity of nest predation may also be considered [START_REF] Major | The contribution of artificial nest experiments to understanding avian reproductive success: a review of methods and conclusions[END_REF] as different predators can share same environmental preferences. This latter phenomenon was observed in the red squirrel [START_REF] Martin | Nest predation in forest birds: influence of predator type and predator's habitat quality[END_REF]: areas with high nest predation by squirrel & Joron, coincided with the proximity of zones used by corvids for foraging. Nevertheless, our observations do not allow us to assess whether this correlation is due to a functional link between the other predators and wild boar or simply shared preferences for the same habitats.

Otherwise, ungulates exclusion by fencing seems to have no effect on abundance of mammal and avian nest predators. Moreover, thorough analyses have shown that marten is the only predator significantly more abundant in fences in Orléans forest. Otherwise, abundance of avian predators is marginally higher in fences. According to these results, we may suspect marten and avian to be the main predators in fences. By the way, marten, jay and great spotted woodpecker were the only predators clearly identified in our study. Yet, none of the many variables based on predator abundance and diversity proved to be related to nest predation rate in our study. This is contradictory with [START_REF] Piper | Effects of edge type and nest height on predation of artificial nests within subtropical Australian eucalypt forests[END_REF], who have shown a high nest predation rates related to high predator abundances on edges.

In our case, predator abundance at a plot-scale may not have been reliably estimated with a single (or two) camera traps. An alternative explanation is that predators may exhibit strong among-individual variability in searching for nests: in that case, predator abundance would be a poor proxy of the predation risk, and possibly a single or very few animals were responsible for all predation events at the plot scale or even at the pair of plot scale. The fact that many nests were predated following the same strategy (nest or eggs removal, holed eggs) in several plots supports this view. Although our nest density was in line with previous studies [START_REF] Andren | Corvid density and nest predation in relation to forest fragmentation: a landscape perspective[END_REF][START_REF] Carpio | Effects of wild boar predation on nests of wading birds in various Swedish habitats[END_REF], it is possible that it was sufficiently high for local predators to specialise on artificial nests. Indeed, it has been shown that predators modify their search behaviour in response to the frequency of occupied nests that they encounter [START_REF] Martin | On the advantage of being different: nest predation and the coexistence of bird species[END_REF]. Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Indirect impact: modification of environment

Beside direct nest predation by ungulates, we expected possible cascading effect of ungulates via herbivory of the lower vegetation strata, reducing available space for building nests while increasing their detectability by predators [START_REF] Vanhinsbergh | A review of possible causes of recent changes in populations of woodland birds in Britain[END_REF][START_REF] Fuller | Recent declines in populations of woodland birds in Britain[END_REF]. Indeed, it has showed in aquatic systems that dense foliage and increased structural heterogeneity can affect bird habitat choice by reducing risk of predation [START_REF] Werner | Ontogenetic habitat shifts in bluegill: the foraging ratepredation risk trade-off[END_REF]. In particular, the foliage cover surrounding the nest leads to a reduction of predation probability by concealing the nest [START_REF] Martin | Nest predation and nest sites[END_REF]. Moreover, predation rates are lower at nests with greater concealment [START_REF] Martin | Breeding productivity considerations: What are the appropriate habitat features for management?[END_REF]. [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF] suggested that dense ground cover may affect the ease of predator to access and to detect eggs in nest. Indeed dense vegetation may inhibit transmission of visual, olfactory or acoustic cues for predators [START_REF] Martin | Nest predation and nest sites[END_REF]. Our results seem to be consistent with this mechanism as predation rate decreased when shrub cover increased. This cascading effect has also been showed by [START_REF] Martin | Nest predation in forest birds: influence of predator type and predator's habitat quality[END_REF], who studied natural nests predation on islands with and without introduced deer. They have shown a decrease in nest survival with the decreasing shrub layer around the nest in response to browsing. In our case, we could not properly demonstrate such a cascade effect as our synchronic study was based on recently fenced plots where lower vegetation strata had not recovered yet from previous browsing pressure. It would be necessary to reproduce our experiment in a few years to prove it formally.

Impacts of ungulates on bird communities

Vegetation modifications induced by ungulates have strong impacts on woodland bird community assemblage [START_REF] Allombert | A natural experiment on the impact of overabundant deer on songbird populations[END_REF]. Particularly understory-dependent bird species are known to be less abundant in highly browsing areas [START_REF] Fuller | Responses of woodland birds to increasing numbers of deer: a review of evidence and mechanisms[END_REF][START_REF] Newson | Modelling large-scale relationships between changes in woodland deer and bird populations[END_REF], due to indirect effect on availability of food and nesting sites [START_REF] Allombert | A natural experiment on the impact of overabundant deer on songbird populations[END_REF][START_REF] Holt | Breeding and post-breeding responses of woodland birds to modification of habitat structure by deer[END_REF]. Accordingly, we assumed that these species would be depleted by the local abundance of predators and in particular ungulates (3 rd hypothesis). Alternatively, predators may be attracted to areas with high bird densities, leading in that case to a positive correlation between the predation rate and bird density. Notably, bird understory-dependent foragers and/or nesters might provide a visual clue for predators by their flies at the ground or shrub level, as it has already been suggested [START_REF] Erikstad | Territorial hooded crows as predators on willow ptarmigan nests[END_REF].

Bird responses to ungulate activities vary according species [START_REF] Fuller | Ecological impacts of increasing numbers of deer in British woodland[END_REF]. In some cases, wild boar high density may be favourable to a limited number of bird species, those become dominant in the community [START_REF] Rousteau | Influence des dynamiques de populations de sangliers (Sus scrofa L.1758) sur la dynamique spatio-temporelle des communautés d'oiseaux forestiers : a field study[END_REF]. Thus, wild boar may promote Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 canopy-dependent or medium tree-layer dependent species as Phylloscopus sibilatrix, Phoenicurus phoenicurus, and by the same time decreasing the abundance of ground forager or ground nester species. Nevertheless, we found neither difference in bird communities between fences and unfences, nor relationship between bird and predators communities. An explanation to that may be woodland birds are mainly influenced by other interactions like habitat and climatic preferences [START_REF] Newton | Population limitation in birds[END_REF]. This is congruent with our observation as 1.7 times bird species in Chambord compared to Orléans. We may suspect the influence of the differences in forest management between them. Indeed in Orléans forest, our experiment was set up in an experimental device, where stand age and density are highly controlled. In comparison, our experiment in Chambord was set up in regeneration stands. This strong local effect due to difference in woodland age structure on bird communities has also been shown by [START_REF] Fuller | Bird Life of Woodland and Forest[END_REF] as many species show strong associations with particular stages.

Influence of nest height in predation rate

Bird communities don't seem to be influenced by ungulate densities and their impacts on forest ecosystem. However, the height of their nest seems to have a significant effect on predation rate, shrub nest being more predated than ground nests. Yet, ground nesting species have long been assumed to suffer greater nest predation than shrub nests species [START_REF] Loiselle | Nest predation in insular and mainland lowland rainforest in Panama[END_REF][START_REF] Wilcove | Nest predation in forest tracts and the decline of migratory songbirds[END_REF]. However, this statement is largely contested by other studies which show the opposite [START_REF] Martin | Artificial nest experiments: effects of nest appearance and type of predator[END_REF][START_REF] Yahner | Effects of forest fragmentation on depredation of artificial nests[END_REF]. According to [START_REF] Seitz | An experimental study of nest predation in adjacent deciduous, coniferous and successional habitats[END_REF], this discrepancy may result from differences of the relative influence of different predator (avian vs mammal) in each study site. She also questioned the realism of artificial nest camouflage which may artificially allow predators to develop a search image for the experimental nests. In our case, our results may be influenced by the fact we met more difficulties to conceal nests in shrub cover than on the ground. Another explanation could concern the ease of avian predators, like Jay, or Great spotted woodpecker, to detect shrub nests from high perches in trees. In the reverse situation, the difficulty for avian predators to find hiding nests in grass could be favourable to terrain mammals like marten or fox. This predation gradient through nesting height may be a selective pressure shaping nest-site use by songbird birds. Wesolowski (2002) assumed that the patterns of nest-site use are best explained as anti-nest predator adaptations, which have been conserved through species evolution because of nest predator pressures. Otherwise, several studies have shown that choice of nesting site can be influenced by among-species competition in the occupation of different vegetation strata [START_REF] Guterrez | Winter foraging behaviour of blackcap and sardinian warbler in a mediterranean scrubland[END_REF][START_REF] Garcia | An experimental test of competition for space between blackcaps Sylvia atricapilla and garden warblers Sylvia borin in the breeding season[END_REF]. We also expected similar effect of Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 the nest shape, with closed nest less predated than open nest like it was shown by Møller (1989). However, contrary to our intuition, nest shape (closed versus open nests) had less influence than nest height in predation rate.

Conclusion

The goal of our study was to investigate the potential effects of ungulate density on nest predation of low-nesting birds and bird communities in forest ecosystems. In order to test this impact, 528 artificial nests with quail eggs were set in 22 pairs of fenced plots excluding ungulates and unfenced plots. One part of these artificial nests was monitored with camera traps to identify predators and assess the frequentation of ungulates and other potential predators in each plot. Bird point counts were also carried out to estimate composition of bird communities in each plot. Our study failed to demonstrate a noticeable egg predation effect of deer and even wild boar. Otherwise no attractive effect on alternative avian or mammalian predators by ungulates was shown. Yet ungulates browsing of low vegetation may facilitate the detection of nests in these layers by these predators. Moreover, a high predation rate seems to be explained by a low shrub cover and nests concealed in shrubs. Finally, bird communities are influenced by neither local abundance of predators, nor those of ungulates.

Our study speaks in favour of conducting further research to better determine the cascading ecological roles of overabundant ungulates on nest predation.

  Acknowledgements ................................................................................................................................... 1. Introduction ......................................................................................................................................... 2. Materials and Methods ....................................................................................................................... 2.1. Study area ................................................................................................................................. 2.2. Experimental design ................................................................................................................. 2.2.1. Artificial nests .................................................................................................................... 2.2.2. Exposition to predation ..................................................................................................... 2.2.3. Camera traps ..................................................................................................................... 2.2.3. Vegetation survey .............................................................................................................. 2.2.4. Birds surveys ...................................................................................................................... 2.3. Data analysis ............................................................................................................................. 3. Results ............................................................................................................................................... 3.1. Effect of fencing on predation ................................................................................................ 3.2. Effect of fencing on nest predator abundances ..................................................................... 3.3. Effect of fencing on bird communities ................................................................................... 3.4. Nest predation risk ................................................................................................................. 4. Discussion .......................................................................................................................................... 4.1. Nest predation risk related to fences ..................................................................................... 4.2. Impacts of ungulates on nest predation ................................................................................ 4.2.1. Direct impact: nest predation ......................................................................................... 4.2.2. Indirect impact: attraction of other predators ................................................................ 4.2.3. Indirect impact: modification of environment ................................................................ 4.3. Impacts of ungulates on bird communities ............................................................................ 4.4. Influence of nest height in predation rate ............................................................................. 5. Conclusion ......................................................................................................................................... Bibliography ........................................................................................................................................... Annexes ................................................................................................................................................. Abstract .....................................................................................................................................................

Fig. 1 .

 1 Fig. 1. Paired representation of predation rate within fences relative to unfences. 1 st period: nest exposition on April; 2 nd period: nest exposition on May; 3 rd period: nest exposition on July

Fig. 2 .

 2 Fig. 2. Averaged (within and outside fences) predation rate according to the 1 st and 2 nd period of exposition in Chambord 2016, suggesting a memory effect. (Mean of predation rate of each pair was calculated between fences and unfences).

  hereafter called "model 1") was retained to explain predation rate (linear mixed effect models: model null deviance = 439.03 with 8 df; model 1 deviance = 422.93 with 10 df; Chi-square test p-value = 0.00003194). Explanatory variables are the height of nest (linear mixed effect models: coefficient = -0.82687, se = 0.26560, p-value = 0.00185)

Fig. 3 .

 3 Fig. 3. Variation in predation rate according to nest height (A) and shrub cover in % (B). Mixed model with a random nested geographical effects, a year and a period of nest exposition fixed effects, indicated that : (A) shrub nests are significantly more predated than ground nests (p-value = 0.002); (B) predation rate significantly decreases when shrub cover increase (p-value =0.020).

Fig. 4 .

 4 Fig. 4. Variation of shrub cover (in %) according to type of plot (fences/unfences). Mixed model with a random geographical effects and a year fixed effects, indicated that shrub cover is higher in fenced than unfenced plots (p-value = 0.009).

Table 1 . Effect of the fencing on bird communities. Bird's richness and abundance were averaged at the plot scale. p-value is obtained from linear mixed effect models, and with geographical (Site and Pairs) and year random effects for comparison between fencing, and with geographical (Pairs and Plots) and a year random effects for comparison between study site.

 1

			Fencing effect	Study site effect	Interaction
		Total in	Total in	p-value of	Total in	Total in	p-value of	p-value
		fences	unfences	difference	Chambord	Orléans	difference	interaction
	Species richness	5.27±0.49 5.50±0.62	0.74	6.42±0.51 3.89±0.40	0.01	0.10
	Abundance of all species	5.77±0.56 5.95±0.68	0.80	7.11±0.56 4.06±0.42	0.02	0.09
	Species richness of ground nester	0.50±0.13 0.60±0.16	0.68	0.50±0.13 0.61±0.16	0.24	0.43
	Species richness of shrub nester	1.73±0.34 1.13±0.14	0.10	2.08±0.27 0.50±0.17	0.44	0.67
	Species richness of ground and foliage forager	1.59±0.16 1.73±0.23	0.73	1.08±0.18 1.44±0.22	0.644	0.45
	Abundance of corvids and woodpeckers	0.86±0.21 1.18±0.23	0.30	1.04±0.23 1.0±0.20	0.02	0.

14 Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Table 2 . Nest predators identified by camera traps' photos. Identification is considered as certain if predator was seen with eggs in mouth and as possible when predator was seen nearby the nest.

 2

		Number of predated nests
		(within fences-unfences)
	Predator identity	Certain	Probable	Total
	Wild boar	0

Impacts of ungulates on nest predation 4.2.1. Direct impact: nest predation

Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 4.2.

  This is congruent with Ivan & Murphy's results showing that exclusion fences are ineffective against avian predators and mammal species (2005). Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017

Table 1 . Characteristics of study sites, study plots and experimental design. * two periods of nest exposure combined

 1 Amanda Cocquelet -Master 2 Ecologie Ethologie -Université Jean Monnet -2016/2017 Annexes

	Site

Nest Mean shrub layer estimation per plot (%) (standard error)

			4,3(2,5)	6,5(3,0)	11,3(2,5)		4,3(1,7)	6,9(3,0)		7,7(4,6)
		Number of nests per plot	12*	12*		12			12
	Camera	Total number of nests Total number of camera traps to monitor nests	48* 6*	48* 12*	9	216	14	9	216	27
		Total number of camera traps to monitor animal frequentation	8*	16*	9		14	9

http://www.oncfs.gouv.fr

Birds of the Western Palearctic Interactive DVD-ROM Version 2.0.2

3 Birds of the Western Palearctic Interactive DVD-ROM Version 2.0.2

Acknowledgements

First and foremost, I am very grateful to my supervisor Frédéric Archaux who, even with a very busy schedule, has always been available (even during his holydays!) to give me precious advice and to supervise me. Thank you for your kindness, your patience and your daily good mood. I really enjoyed working with you on this crazy subject!

Details of models and summaries

All variable abbreviations used in models below are listed in the table 2 in annexes. forest ecosystem are notably known to impact negatively woodland bird communities. In this study we investigated the potential effects of ungulate density on nest predation of lownesting birds and bird communities in forest ecosystems. In order to test this impact, 528 artificial nests monitored with camera traps were set both in fenced plots excluding ungulates and in unfenced plots. We used (generalized) linear mixed models to explain (1) impact of ungulates on predation, on other potential predators and on bird communities, and (2) to know which variables explained spatio-temporal variation in nest predation rate among those related to plot type (fenced/unfenced), ungulates and other egg predators, bird communities and plot vegetal features. Our study failed to demonstrate a noticeable egg predation effect of deer and even wild boar, as well as any attractive effect on alternative avian or mammalian predators.

Yet ungulates browsing of low vegetation may facilitate the detection of nests in these layers by these predators. Finally, bird communities are influenced by neither local abundance of predators, nor those of ungulates.