Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the gl... more Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the global biodiversity crisis. Their global decline caused by the fungal agentBatrachochytrium dendrobatidis(Bd) is well known. Declines of Mesoamerican salamanders of the family Plethodontidae, mainly affecting high elevation species, have equally been attributed toBd. Here we report the prevalence ofBdin a population of a high elevationBolitoglossaspecies in Nicaragua, since its description in 1999 until 2011 in the absence of any obvious population declines. Our findings show a low prevalence in an environmental context where pathogen driven declines would be expected to occur.
Spatial variation in habitat riskiness has a major influence on the predator–prey space race. How... more Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objective was to test how prey species spend time among habitats that differ in riskiness, and how shared predation modulates the space use by prey species. We studied a one‐predator, two‐prey system in a coastal dune landscape in the Netherlands with the European hare (Lepus europaeus) and European rabbit (Oryctolagus cuniculus) as sympatric prey species and red fox (Vulpes vulpes) as their main predator. The fine‐scale space use by each species was quantified using camera traps. We quantified residence time as an index of space use. Hares and rabbits spent time differently among habitats that differ in riskiness. Space use by predators and habitat riskiness affected space use by hares more strongly than space use by rabbits. Residence time of hare was shorter in habitats in which the predator was efficient in searching or capturing prey species. However, hares spent more time in edge habitat when foxes were present, even though foxes are considered ambush predators. Shared predation affected the predator–prey space race for hares positively, and more strongly than the predator–prey space race for rabbits, which were not affected. Shared predation reversed the predator–prey space race between foxes and hares, whereas shared predation possibly also released a negative association and promoted a positive association between our two sympatric prey species. Habitat riskiness, species presence, and prey species’ escape mode and foraging mode (i.e., central‐place vs. noncentral‐place forager) affected the prey space race under shared predation
Antipredator responses could affect nutrient intake, which could lead to nutritional deficits. Ho... more Antipredator responses could affect nutrient intake, which could lead to nutritional deficits. However, little is known about the antipredator response of small herbivores because most are nocturnal or crepuscular and therefore very difficult to study in the field. Therefore we experimentally assessed the effect of a reactive response to predation risk on the nutrient (i.e., phosphorous) intake of the European hare (Lepus europaeus) by using three different playback sounds. Additionally, we studied the time spent being costly vigilant, the time spent foraging, and the vegetation height in which the hares were present by using accelerometers and GPS. Our results showed that elevated predation risk from our playback experiment did not affect the 1) phosphorus intake, 2) time spent being costly vigilant, and 3) time spent in tall vegetation. However, elevated predation risk did increase the time spent foraging. Possibly hares spent more time foraging with an increased predation risk be...
1. Camera trap technology has galvanized the study of predator-prey ecology in wild animal commun... more 1. Camera trap technology has galvanized the study of predator-prey ecology in wild animal communities by expanding the scale and diversity of predator-prey interactions that can be analyzed. While observational data from systematic camera arrays have informed inferences on the spatiotemporal outcomes of predator-prey interactions, the capacity for observational studies to identify mechanistic drivers of species interactions is limited. 2. Experimental study designs that utilize camera traps uniquely allow for testing hypothesized mechanisms that drive predator and prey behavior, incorporating environmental realism not possible in the lab while benefiting from the distinct capacity of camera traps to generate large data sets from multiple species with minimal observer interference. However, such pairings of camera traps with experimental methods remain underutilized. 3. We review recent advances in the experimental application of camera traps to investigate fundamental mechanisms un...
During times of high activity by predators and competitors, herbivores may be forced to forage in... more During times of high activity by predators and competitors, herbivores may be forced to forage in patches of low-quality food. However, the relative importance in determining where and what herbivores forage still remains unclear, especially for small and intermediate-sized herbivores. Our objective was to test the relative importance of predator and competitor activity, and forage quality and quantity on the proportion of time spent in a vegetation type and the proportion of time spent foraging by the intermediate-sized herbivore European hare (Lepus europaeus). We studied red fox (Vulpes vulpes) as a predator species and European rabbit (Oryctolagus cuniculus) as a competitor. We investigated the time spent at a location and foraging time of hare using GPS with accelerometers. Forage quality and quantity was analysed based on hand-plucked samples of a selection of the locally most important plant species in the diet of hare. Predator and competitor activity was investigated using a network of camera traps. Hares spent a higher proportion of time in vegetation types that contained a higher percentage of fibres (i.e., NDF). Besides, hares spent a higher proportion of time in vegetation types that contained relatively low food quantity and quality of forage (i.e., high percentage of fibres) during days that foxes (Vulpes vulpes) were more active. Also during days that rabbits (Oryctolagus cuniculus) were more active, hares spent a higher proportion of time foraging in vegetation types that contained a relatively low quality of forage. Although predation risk affected space use and foraging behaviour, and competition affected foraging behaviour, our study shows that food quality and quantity more strongly affected space use and foraging behaviour than predation risk or competition. It seems that we need to reconsider the relative importance of the landscape of food in a world of fear and competition
Camera detection data (6 files in csv format). Direct distances and angles of first detection of ... more Camera detection data (6 files in csv format). Direct distances and angles of first detection of hare, rabbit and fox in open and half-open vegetation structur
We assessed the hypothesized negative correlation between the influence of multiple predators and... more We assessed the hypothesized negative correlation between the influence of multiple predators and body condition and fecundity of the European hare, from 13 areas in the Netherlands. Year‐round abundance of predators was estimated by hunters. We quantified predator influence as the sum of their field metabolic rates, as this sum reflects the daily food requirements of multiple individuals. We determined the ratio between body mass and hindfoot length of hares as an index of body condition and the weight of their adrenal gland as a measure of chronic exposure to stress, and we counted the number of placental scars to estimate fecundity of hares. As hypothesized, we found that the sum of field metabolic rate of predators was negatively correlated with body condition and the number of placental scars, whereas it was positively related to the weight of the adrenal glands. In contrast to the sum of the field metabolic rate, the total number of predators did not or weakly affect the inves...
prioritization and performance evaluation of the conservation area network for the Moroccan herpe... more prioritization and performance evaluation of the conservation area network for the Moroccan herpetofauna: a preliminary assessment
Community-based nature management is becoming more common around the world. Nongovernmental natur... more Community-based nature management is becoming more common around the world. Nongovernmental nature organisations in the Netherlands, such as Natuurmonumenten, are responding to this trend by setting up communities. Since Natuurmonumenten has limited experience in this respect, this study aimed to provide insight in the processes and effects of the set-up of a nature community around two newly acquired nature areas in Delfzijl. The processes of the set-up of this community were studied by observing the community group and the Natuurmonumenten delegates, and by subjecting the delegates of Natuurmonumenten to a questionnaire. Further insights were gained by measuring the effects of the processes of the set-up of the community using a preand post-test among the community group and a control group. The observations indicated that the Natuurmonumenten delegates were very dedicated during the set-up of this community, while the community group was hesitant and somewhat non-active during mo...
Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the gl... more Amphibians are the most threatened terrestrial vertebrates on the planet and are iconic in the global biodiversity crisis. Their global decline caused by the fungal agentBatrachochytrium dendrobatidis(Bd) is well known. Declines of Mesoamerican salamanders of the family Plethodontidae, mainly affecting high elevation species, have equally been attributed toBd. Here we report the prevalence ofBdin a population of a high elevationBolitoglossaspecies in Nicaragua, since its description in 1999 until 2011 in the absence of any obvious population declines. Our findings show a low prevalence in an environmental context where pathogen driven declines would be expected to occur.
Spatial variation in habitat riskiness has a major influence on the predator–prey space race. How... more Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objective was to test how prey species spend time among habitats that differ in riskiness, and how shared predation modulates the space use by prey species. We studied a one‐predator, two‐prey system in a coastal dune landscape in the Netherlands with the European hare (Lepus europaeus) and European rabbit (Oryctolagus cuniculus) as sympatric prey species and red fox (Vulpes vulpes) as their main predator. The fine‐scale space use by each species was quantified using camera traps. We quantified residence time as an index of space use. Hares and rabbits spent time differently among habitats that differ in riskiness. Space use by predators and habitat riskiness affected space use by hares more strongly than space use by rabbits. Residence time of hare was shorter in habitats in which the predator was efficient in searching or capturing prey species. However, hares spent more time in edge habitat when foxes were present, even though foxes are considered ambush predators. Shared predation affected the predator–prey space race for hares positively, and more strongly than the predator–prey space race for rabbits, which were not affected. Shared predation reversed the predator–prey space race between foxes and hares, whereas shared predation possibly also released a negative association and promoted a positive association between our two sympatric prey species. Habitat riskiness, species presence, and prey species’ escape mode and foraging mode (i.e., central‐place vs. noncentral‐place forager) affected the prey space race under shared predation
Antipredator responses could affect nutrient intake, which could lead to nutritional deficits. Ho... more Antipredator responses could affect nutrient intake, which could lead to nutritional deficits. However, little is known about the antipredator response of small herbivores because most are nocturnal or crepuscular and therefore very difficult to study in the field. Therefore we experimentally assessed the effect of a reactive response to predation risk on the nutrient (i.e., phosphorous) intake of the European hare (Lepus europaeus) by using three different playback sounds. Additionally, we studied the time spent being costly vigilant, the time spent foraging, and the vegetation height in which the hares were present by using accelerometers and GPS. Our results showed that elevated predation risk from our playback experiment did not affect the 1) phosphorus intake, 2) time spent being costly vigilant, and 3) time spent in tall vegetation. However, elevated predation risk did increase the time spent foraging. Possibly hares spent more time foraging with an increased predation risk be...
1. Camera trap technology has galvanized the study of predator-prey ecology in wild animal commun... more 1. Camera trap technology has galvanized the study of predator-prey ecology in wild animal communities by expanding the scale and diversity of predator-prey interactions that can be analyzed. While observational data from systematic camera arrays have informed inferences on the spatiotemporal outcomes of predator-prey interactions, the capacity for observational studies to identify mechanistic drivers of species interactions is limited. 2. Experimental study designs that utilize camera traps uniquely allow for testing hypothesized mechanisms that drive predator and prey behavior, incorporating environmental realism not possible in the lab while benefiting from the distinct capacity of camera traps to generate large data sets from multiple species with minimal observer interference. However, such pairings of camera traps with experimental methods remain underutilized. 3. We review recent advances in the experimental application of camera traps to investigate fundamental mechanisms un...
During times of high activity by predators and competitors, herbivores may be forced to forage in... more During times of high activity by predators and competitors, herbivores may be forced to forage in patches of low-quality food. However, the relative importance in determining where and what herbivores forage still remains unclear, especially for small and intermediate-sized herbivores. Our objective was to test the relative importance of predator and competitor activity, and forage quality and quantity on the proportion of time spent in a vegetation type and the proportion of time spent foraging by the intermediate-sized herbivore European hare (Lepus europaeus). We studied red fox (Vulpes vulpes) as a predator species and European rabbit (Oryctolagus cuniculus) as a competitor. We investigated the time spent at a location and foraging time of hare using GPS with accelerometers. Forage quality and quantity was analysed based on hand-plucked samples of a selection of the locally most important plant species in the diet of hare. Predator and competitor activity was investigated using a network of camera traps. Hares spent a higher proportion of time in vegetation types that contained a higher percentage of fibres (i.e., NDF). Besides, hares spent a higher proportion of time in vegetation types that contained relatively low food quantity and quality of forage (i.e., high percentage of fibres) during days that foxes (Vulpes vulpes) were more active. Also during days that rabbits (Oryctolagus cuniculus) were more active, hares spent a higher proportion of time foraging in vegetation types that contained a relatively low quality of forage. Although predation risk affected space use and foraging behaviour, and competition affected foraging behaviour, our study shows that food quality and quantity more strongly affected space use and foraging behaviour than predation risk or competition. It seems that we need to reconsider the relative importance of the landscape of food in a world of fear and competition
Camera detection data (6 files in csv format). Direct distances and angles of first detection of ... more Camera detection data (6 files in csv format). Direct distances and angles of first detection of hare, rabbit and fox in open and half-open vegetation structur
We assessed the hypothesized negative correlation between the influence of multiple predators and... more We assessed the hypothesized negative correlation between the influence of multiple predators and body condition and fecundity of the European hare, from 13 areas in the Netherlands. Year‐round abundance of predators was estimated by hunters. We quantified predator influence as the sum of their field metabolic rates, as this sum reflects the daily food requirements of multiple individuals. We determined the ratio between body mass and hindfoot length of hares as an index of body condition and the weight of their adrenal gland as a measure of chronic exposure to stress, and we counted the number of placental scars to estimate fecundity of hares. As hypothesized, we found that the sum of field metabolic rate of predators was negatively correlated with body condition and the number of placental scars, whereas it was positively related to the weight of the adrenal glands. In contrast to the sum of the field metabolic rate, the total number of predators did not or weakly affect the inves...
prioritization and performance evaluation of the conservation area network for the Moroccan herpe... more prioritization and performance evaluation of the conservation area network for the Moroccan herpetofauna: a preliminary assessment
Community-based nature management is becoming more common around the world. Nongovernmental natur... more Community-based nature management is becoming more common around the world. Nongovernmental nature organisations in the Netherlands, such as Natuurmonumenten, are responding to this trend by setting up communities. Since Natuurmonumenten has limited experience in this respect, this study aimed to provide insight in the processes and effects of the set-up of a nature community around two newly acquired nature areas in Delfzijl. The processes of the set-up of this community were studied by observing the community group and the Natuurmonumenten delegates, and by subjecting the delegates of Natuurmonumenten to a questionnaire. Further insights were gained by measuring the effects of the processes of the set-up of the community using a preand post-test among the community group and a control group. The observations indicated that the Natuurmonumenten delegates were very dedicated during the set-up of this community, while the community group was hesitant and somewhat non-active during mo...
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Papers by Martijn Weterings