DOI: 10.5061/dryad.mpg4f4r0q
title: Predation risk can modify the foraging behaviour of frugivorous carnivores: implications of rewilding apex predators for plant-animal mutualisms

description: Apex predators play key roles in food webs and their recovery can trigger
 trophic cascades in some ecosystems. Intra-guild competition can reduce
 the abundances of smaller predators and perceived predation risk can alter
 their foraging behaviour thereby limiting seed dispersal by frugivorous
 carnivores. However, little is known about how plant-frugivore mutualism
 could be disturbed in the presence of larger predators. We evaluated the
 top-down effect of the regional superpredator, the Iberian lynx (Lynx
 pardinus), on the number of visits and fruits consumed by medium-sized
 frugivorous carnivores, as well as the foraging behaviour of identified
 individuals, by examining the consumption likelihood and the foraging
 time. We carried out a field experiment in which we placed Iberian pear
 (Pyrus bourgaeana) fruits beneath fruiting trees and monitored pear
 removal by frugivorous carnivores, both inside and outside of lynx ranges.
 Using camera traps, we recorded the presence of the red fox (Vulpes
 vulpes), the Eurasian badger (Meles meles) and the stone marten (Martes
 foina), as well as the number of fruits they consumed and their time spent
 foraging. Red fox was the most frequent fruit consumer carnivore. We found
 there were fewer visits and less fruit consumed by foxes inside of lynx
 ranges, but lynx presence did not seem to affect badgers. We did not
 observe any stone marten visits inside of lynx territories. The foraging
 behaviour of red foxes was also altered when inside of lynx ranges whereby
 foxes were less efficient, consuming less fruit per unit of time and
 having shorter visits. Local availability of fruit resources, forest
 coverage and individual personality also were important variables to
 understand visitation and foraging in a landscape of fear. 5. Our results
 show a potential trophic cascade from apex predators to primary producers.
 The presence of lynx can reduce frugivorous carnivore numbers and induce
 shifts in their feeding behaviour that may modify the seed dispersal
 patterns with likely consequences for the demography of many
 fleshy-fruited plant species. We conclude that knowledge of the ecological
 interactions making up trophic webs is anasset to design effective
 conservation strategies, particularly in rewilding programs.
description: Our experimental design compared the foraging of pear fruits in
 areas where the Iberian lynx was present or absent. We placed depots of 30
 fruits beneath 30 Iberian pear adult trees. Fifteen fruit depots were
 located beneath pear trees inside the home ranges of two lynx couples, and
 the remaining 15 fruit depots were located at least 4.6 km away from any
 lynx home range and used as controls. We placed a camera trap (Scoutguard
 SG562-C; white led) in front of each fruit depot to record the species
 that visited the trees, the number of fruits consumed, and the time spent.
 The experiment lasted 15 consecutive days. We visited each camera trap
 site every 5-days to refill the fruit depots. We reached an overall effort
 of 437 days in which cameras were working and offered 2700 fruits of
 Iberian pear during the experiment.  We processed all
 images taken by camera-traps in the fruit depots (n = 130269) and recorded
 the species, the date, and each event's hour. The number of fruits
 consumed in each visit was estimated by comparing each image with the
 previous one to count the number of fruits left. The time spent per visit
 was calculated as the difference between the time of the first image and
 the last one of each independent event, considering records separated by
 longer than 30 min as independent events (Linkie & Ridout, 2011).
 We considered one event per individual of the red fox when more than one
 was recorded in the same image because we could identify them
 individually. Foxes have particular fur marks that make them easily
 recognizable, mainly in legs, face and tail. Two experts identified the
 fox individuals independently and individualized more than 75% of images
 recorded by consensus.  We counted the number of
 individual fruiting trees in the patches and visually estimated the
 individual crop size. We transformed our data on crop size into a
 logarithmic fruit abundance index (FAI): 0 = no fruits; 1 = 1–10 fruits; 2
 = 11–100; 3 = 101–1,000; 4 = 1001–10,000; 5 &gt; 10,000. (see Saracco,
 Collazo, & Groom, 2004). The overall crop size was calculated by
 adding the number of fruits on the canopy to the number of ripe fruits
 fallen on the ground every time we replenish the fruits in the depots
 (three times in total). We also recorded the forest cover inside a 100 m
 circular buffer around each isolated tree and around each MCP including
 all pear trees within the patch. We digitized the surface covered by
 forest from a high-resolution (0.5 m) orthophotography and calculated the
 percentage of forest cover within buffers (IGN, 2016).
 References IGN. (2016). Historical digital aerial orthophotographs of the Spanish National Orthophoto Program (PNOA). <em>Available from: </em>http://centrodedescargas.cnig.es/CentroDescargas/linkUnMD.<em> [Accessed 15 Sept 2020]. Spanish</em>. Linkie, M., & Ridout, M. S. (2011). Assessing tiger-prey interactions in Sumatran rainforests. <em>Journal of Zoology</em>, <em>284</em>(3), 224–229. doi: 10.1111/j.1469-7998.2011.00801.x Saracco, J. F., Collazo, J. A., & Groom, M. J. (2004). How do frugivores track resources? Insights from spatial analyses of bird foraging in a tropical forest. <em>Oecologia</em>, <em>139</em>(2), 235–245. doi: 10.1007/s00442-004-1493-7