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# Wolves on the hunt in sheep depredation hotspots: what are the effects of the presence of livestock guarding dogs (LGDs) and fences?

Ricardo N. Simon, Clément Calenge, Nolwenn Drouet-Hoguet, Nicolas Jean, Pierre-Yves Quenette

► To cite this version:

Ricardo N. Simon, Clément Calenge, Nolwenn Drouet-Hoguet, Nicolas Jean, Pierre-Yves Quenette. "Wolves on the hunt in sheep depredation hotspots: what are the effects of the presence of livestock guarding dogs (LGDs) and fences?". Predator-Prey Interactions, Oct 2022, Lucca (Barga), Italy. hal-04381623

HAL Id: hal-04381623

https://ofb.hal.science/hal-04381623v1

Submitted on 9 Jan 2024

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# WOLVES ON THE HUNT IN SHEEP DEPREDATION HOTSPOTS

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OFB
OFFICE FRANÇAIS
DE LA BIODIVERSITÉ

## WHAT ARE THE EFFECTS OF THE PRESENCE OF LIVESTOCK GUARDING DOGS (LGD) AND FENCES?

R. N. SIMON, C. CALENGE, N. DROUET-HOGUET, N. JEAN & P.-Y. QUENETTE

ricardo.simon@ofb.gouv.fr

## FIELD OBSERVATIONS MADE DURING LETHAL CONTROL INTERVENTIONS TO PROTECT LIVESTOCK

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**BAYESIAN ANALYSIS:** sequence of mixed effects models to estimate the conditional probability of each behavioural phase and the conditional probability of shots being fired after each phase.

$$ \text{Logit}(\text{Prob.}) = \text{weather} + \text{habitat} + \text{depredation pressure} + \text{LDG} + \text{fences} + \text{random observer and year effects} $$

**A posteriori POWER ANALYSIS:** given the uncertainty in the data, LGD or fences should have **divided P(approach) by 2** and **P(attack) by 3** for their effects to have had 80% chance of being detected.

**RESULTS:** NO OBSERVED EFFECT OF LGD OR FENCES IN HOTSPOTS EVALUATED WHEN OBSERVERS PRESENT

- LGD ON APPROACH: $\beta = 0.34 [-0.55 - 1.3]$

- LGD ON ATTACK: $\beta = 0.18 [-1.1 - 1.4]$

- FENCES ON APPROACH: $\beta = 0.28 [-0.63 - 1.24]$

- FENCES ON ATTACK: $\beta = -0.1 [-1.3 - 1.1]$

$\beta$ = estimated coefficient
[90% credible interval]

**UNCERTAINTY DUE TO LARGE BETWEEN-OBSERVER AND BETWEEN-YEAR VARIABILITY**

**ARE THESE EFFECT SIZES REASONABLE EXPECTATIONS?**

In any case, greater efforts are needed to measure other parameters **beyond the mere presence of preventive measures** to protect livestock.