Papers by Jonathan Jumeau
Ecological Engineering, 2016
A great number of wildlife underpasses are used to mitigate the environmental impact of urbanizat... more A great number of wildlife underpasses are used to mitigate the environmental impact of urbanization and road infrastructure expansion, thus restoring ecological connectivity. However,the simultaneous use
of these structures by small mammals and their predators could result in increased predation rates in these passages or lead small mammals to avoid using them. This would be particularly harmful to small populations or threatened species such as the European hamster (Cricetus cricetus). To overcome this problem and to provide lateral escape opportunities along the length of the underpasses, we developed
an anti-predation tube. We tested the features (shape and size) of this device under laboratory conditions and validated its use by captive European hamsters. Our results reveal that the optimal anti-predation
tube has a diameter of 10 cm, a curved shape and lateral openings. This device will be tested under field conditions to validate its efficiency to protect small mammals using wildlife underpasses. If confirmed,
this system could considerably improve crossing conditions in bigger tunnels and on bridges such as agricultural under- or overpasses, which have been unsuitable for small animals until now.
Sciences Eaux & Territoires, 2018
La fragmentation des habitats causée par les infrastructures linéaires de transport, dont les rou... more La fragmentation des habitats causée par les infrastructures linéaires de transport, dont les routes, isole génétiquement les populations animales et provoque leur déclin. Afin de reconnecter ces populations de chaque côté de la route, des passages à faune sont construits mais leur efficacité à l’échelle individuelle pour les micromammifères n’est pas connue. Un protocole de Capture-Marquage-Recapture a été mené sur le mulot sylvestre (Apodemus sylvaticus) et le campagnol des champs (Microtus arvalis) habitant les dépendances vertes de sections routières équipés ou non de passages à faune. Les probabilités de dispersion entre les deux côtés de la route, avec et sans passage à faune, ont été calculées.
Une restauration partielle par les passages à faune des continuités écologiques pour les micromammifères a été mise en évidence. En effet, les seules sections routières sur lesquelles des individus traversant la route ont été observés étaient celles équipées d’un passage à faune. Cependant, la probabilité de dispersion d’un côté à l’autre de la route serait trop faible pour assurer, à elle-seule, un brassage génétique suffisant. Ainsi, dans un objectif de conservation des espèces, une amélioration des passages à faune pour les micromammifères est nécessaire.
European Journal of Wildlife Research, 2020
During road construction, stormwater ponds are created to address sanitation, water treatment and... more During road construction, stormwater ponds are created to address sanitation, water treatment and the containment of any accidental pollution issues. These environments are not intended to be habitats, so exclosure measures (e.g., fences, barriers…) are implemented to prevent animals to gain access to them. However, the modification of the natural landscape for human needs resulted in the disappearance of most wetlands. Our hypothesis was that depending on the water pollutant concentrations, the stormwater water ponds could serve as refuge habitat for wetlands species like amphibians. Thus, we evaluated the suitability of stormwater ponds as a habitat for amphibians by studying 82 such structures in the agricultural plain of the Bas-Rhin. The proportion of stormwater ponds hosting amphibians and specific species abundances and richness were quantified as community parameters. They were explained using factors such as pond design (e.g., size, depth, slopes...), road-induced pollutants, land use and exclosures measures. Significance of these factors was assessed by Boosted Regression Tree models. Species dependent effects were studied using detrented correspondence analysis. Amphibians were found in 84% of stormwater ponds, with an average of 19.51 adults and 2.44 species per pond. We found 83% of species previously detected in Bas-Rhin, including rare and protected ones. Neither exclosures measures nor pollutants concentration were correlated with community parameters. The best explanatory factors were land use and pond design. For ponds with pollutant concentrations similar to those quantified in this study, we recommend reallocating the efforts made for exclosure to improve pond design and to the creation of semi-natural ponds as additional compensatory measures. Design of stormwater ponds should be systematically validated by a herpetologist to avoid mortal traps. Ponds should be large and have a permanent minimum water level even in droughts.
Urban Ecosystems, 2017
Intensification of agriculture and land consolidation policy induced the removal of most natural ... more Intensification of agriculture and land consolidation policy induced the removal of most natural features from farmland, reducing the habitat of many wild species. Abandoned WWII bunkers, unaffected by land consolidation, are a potential shelter for wildlife and could be used as burrows by carnivores such as European badgers and red foxes.
We explored 182 abandoned bunkers in a farmland area in eastern France in summer 2016. Bunkers were located in crops, forests, or groves. Over a three-month period, signs of presence, the number and type of burrows inside the bunkers and in their immediate vicinity were noted. Environmental variables were obtained using GIS, and binomial models were created to reveal parameters influencing bunker use by badgers and foxes. The degree of bunkers burrowing was used as a co-variable. Twenty-one groves without bunkers were also studied in order to estimate the added value of bunkers in groves.
Badger and fox tracks were found on 34% of the sites, and burrows on 24% of them with similar rates for badgers and foxes. Animals used partially buried bunkers more than underground or overground bunkers. The sizes of annual crops and urban areas around the bunker were positively correlated with bunker use. The presence of a bunker in groves was positively correlated with the presence of burrows in groves.
Basic and Applied Ecology, 2017
Road construction creates new habitats for a variety of species. In intensive farming landscapes,... more Road construction creates new habitats for a variety of species. In intensive farming landscapes, road verges may be the only suitable habitat for rodents. However, little attention has been paid to other road-related landscape elements (RRLEs), such as excavation slopes or the central islands of roundabouts, and their importance in a rodent territory. This study investigated all types of RRLE in terms of rodent abundances and habitat quality. RRLEs were compared with the semi-natural elements of the studied landscape using a capture-mark-recapture protocol. Four species and 3,154 individuals were captured over a period of four months. Relative abundance and habitat quality were higher in RRLEs than in semi-natural elements. Mapping of the landscape showed that 86% of crop fields are accessible to Microtus arvalis (and almost 100% for Apodemus sylvaticus) from road verges. Our results highlight the importance of road verges and all other RRLEs in the conservation of species diversity in intensive farming landscapes.
Ecology and Evolution, 2017
In the current context of biodiversity loss through habitat fragmentation, the effectiveness of w... more In the current context of biodiversity loss through habitat fragmentation, the effectiveness of wildlife crossings, installed at great expense as compensatory measures, is of vital importance for ecological and socioeconomic actors. The evaluation of these structures is directly impacted by the efficiency of monitoring tools (camera traps…), which are used to assess the effectiveness of these crossings by observing the animals that use them. The aim of this study was to quantify the efficiency of camera traps in a wildlife crossing evaluation. Six permanent recording video systems sharing the same field of view as six Reconyx HC600 camera traps installed in three wildlife underpasses were used to assess the exact proportion of missed events (event being the presence of an animal within the field of view), and the error rate concerning underpass crossing behavior (defined as either Entry or Refusal). A sequence of photographs was triggered by either animals (true trigger) or artefacts (false trigger). We quantified the number of false triggers that had actually been caused by animals that were not visible on the images ("false" false triggers). Camera traps failed to record 43.6% of small mammal events (voles, mice, shrews, etc.) and 17% of medium-sized mammal events. The type of crossing behavior (Entry or Refusal) was incorrectly assessed in 40.1% of events, with a higher error rate for entries than for refusals. Among the 3.8% of false triggers, 85% of them were "false" false triggers. This study indicates a global underestimation of the effectiveness of wildlife crossings for small mammals. Means to improve the efficiency are discussed.
K E Y W O R D S camera trapping, false trigger, monitoring study, small mammals, triggered cameras, wildlife crossings
Thesis Chapters by Jonathan Jumeau
Université de Strasbourg, 2017
Habitats and landscape fragmentation, caused by linear land transports infrastructures, is one of... more Habitats and landscape fragmentation, caused by linear land transports infrastructures, is one of the major cause for the current loss of biodiversity. Among those infrastructures, road is a major cause of fragmentation, especially as it possess specific traffic-linked effects, which induces wildlife-vehicles collisions and landscape pollution. In order to decrease those negative effects, mitigation measures are taken, among which wildlife crossings, enabling wildlife to cross the road. Road also creates new potential habitats for small wildlife species in anthropogenic and fragmented landscapes.
In this essay are shown (1) the potential as habitat of different road-linked elements; (2) the possibility to anticipate wildlife-vehicles collisions in order to improve the position of mitigation measures; (3) the importance of methodology in the evaluation of wildlife crossings effectiveness; and (4) the possibility to improve existing wildlife crossings.
Those results will allow improving landscape defragmentation strategies
Conference Presentations by Jonathan Jumeau
IENE2016, 2016
Monitoring wildlife passages allow scientists to improve effectiveness of these structures by ada... more Monitoring wildlife passages allow scientists to improve effectiveness of these structures by adapting their conception, location and planning. To perform the surveys, infrared triggered cameras are probably the most used technique. Indeed, these small photographic cameras with an invisible flash are well adapted to capture a wide variety of species, even when used inside the narrowest underpass.
However, few studies have investigated the efficiency of these devices to systematically and automatically capture a majority of the passage events (PE), or their impact on wildlife passages frequentation. How many animals are missed by the device? Is the reliability dependent on type of species ? What are the best sensors’ parameters? Is there an impact of the devices on animals’ behavior? How many days are needed to make a sufficient survey of an underpass? These are the questions we asked to improve the knowledge in triggered camera utilization.
From April 2012 to June 2013, we monitored 12 underpasses located in Alsace (East France) with both triggered photographic cameras (Reconyx HC600) and video cameras. Video cameras recorded 24 hours a day and 7 days per week in order to observe all PE of all species and identify every event missed by triggered cameras configured in 5 different motion/thermal ratios. The behavior of carnivores was recorded in order to assess possible disturbance by the devices on the animals. Finally, we performed a correlation between the number of monitoring days and the diversity of species observed.
We found that in small box culverts, 47% of small mammals (voles, mice, shrews) PE and 17% of medium-sized mammals PE (foxes, badgers and other mustelids) are missed by triggered cameras. Moreover, we demonstrated that whatever the season, motion/thermal ratios favoring the motion sensor missed less events than ratios favoring the thermal sensor. Despite every species likely to use our culverts are detected, we found that a minimum of five months were needed to detect 90% of the overall specific diversity over the study period, 3 months more than the duration recommended in previous studies. Monitoring devices disrupted medium-sized mammals during the first five weeks after their installation. There were also fewer carnivores the night after our presence on the field to replace batteries and memory cards.
Even by using the latest technologies, our results point out a significant underestimation of wildlife passage utilization which can introduce an important bias to conclusions about effectiveness of faunal passage structures.
IENE2016, 2016
Since the 1970’s the intensive farming has led to shape new landscapes of huge single-crops field... more Since the 1970’s the intensive farming has led to shape new landscapes of huge single-crops fields, often to the detriment of natural refuges for small mammals and birds, like hedgerows or groves. This type of landscape is frequent in Alsace (France) where hectares are only covered by corn and wheat without interruption leading us to speak about biological desert or unstable ecosystem. Indeed, about the few species living there like rodents, wheat fields are mown during the breeding season in July and corn fields cannot be considered as habitat for these species. They therefore have to survive from July to April without refuges, but few survive more than a few weeks.
When a road is built, potential substitution environments (named road bound landscape elements or RBLE) appear like (1) road verges, (2) storm-water basins, (3) excavation slopes or even (4) middle of roundabouts. Indeed, road verges are for example well known to be habitats for some butterflies, orchids or rodents and storm-water basins are frequently occupied by amphibians or birds. However, the habitat potentiality of all RBLE is not known and even if they could be beneficial for the environment, such hypothesis is not considered during current road environmental studies. Thus, to study the ability of RBLE to be suitable habitats, we have compared these 4 RBLE to two different usual crops fields of corn and wheat. Four replicates of these 6 different habitats were selected in an intensive farming landscape.
To characterize differences in habitat quality, indexes of rodents populations abundance (capture-mark-recapture) and qualities (body condition and survival based on Huggin’s Robust Design model) have been investigated. The study was conducted from May 2015 to August 2015 with 4 captures sessions of 4 consecutive days.
We captured 3166 micromammals with an average of 66 individuals per day. These individuals were distributed in four different species: wood mouse (Apodemus sylvaticus), bank vole (Myodes glareolus), commun vole (Microtus arvalis) and Greater white-toothed shrew (Crocidura russula). Following results concern Microtus arvalis only. We found a greater abundance of individuals in every RBLE than in controls (7.5 times more in average), with almost no individuals in corn crops (< 2 per studied crop). This effect is even stronger in July when wheat crops are mown (0,2 individuals/m² in RLBE vs 0,006 individuals/m² in controls). There is also no significant difference in terms of survival and body condition index between sites with sufficient captured individuals (RLBE and wheat corn only).
These results lead us to consider all road bund landscapes elements (not only road verges) as sustainable habitats which can favor both rodents (and probably shrews too) and predators communities. However, the respective advantages (rodent vs predators) may be difficult to consider in the light of the Predation Release Hypothesis: i.e. a small number of predators will profit of these RBL habitats.
We recommend taking account damages these rodents can cause to nearest crops (financial compensations to farmers), road hedgerows (plants protections, fences) and structures like basins during roads environmental impact studies and road conception, particularly in years of great rodent abundance. Finally, if the rodents’ abundances in RBLE have to be decreased, the employed methods need to be considered in the light of other RBLE taxa such as butterflies and orchids.
SFE2016, 2016
With roads construction, stormwater ponds are created in a sanitation purpose, water treatment, a... more With roads construction, stormwater ponds are created in a sanitation purpose, water treatment, and containment of any accidental pollution. These environments are not intended to serve as habitats; hence
partitioning measures are installed to prevent animals to access to them. In a context of intensive farming landscape, land consolidation has led to the removal of most wetlands. Moreover, as basins are potential habitats for species deprived of their environments, it is not rare to find animal communities into the basins, including amphibian, particularly sensitive to pollutants. The effectiveness and relevance of partitioning measures designed to stop amphibians from
entering the basins is thus questioned regarding their impact on amphibians development. The richness and abundance of amphibians were collected using POPamphibian protocol on more than eighty stormwater and natural ponds. Explanatory variables are water physicochemical parameters including levels of pollution, surrounding land use (like suitable habitats and corridors) and characteristics of basin including partitioning measures. Amphibians have been found in most basins at different stages of development, so partitioning measures do not seem effective. No effect of pollution level was observed. The surrounding environment is the best predictive variable of presence of breeding. However, it is difficult to attribute the decline of the offspring to pollution or natural predation pressure. In conclusion, partitioning measures are neither effective nor relevant in the context of an intensive farming landscape. We invite roads manager to remove partitioning measures from stormwater ponds or/and to create substitution puddles close to them.
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Papers by Jonathan Jumeau
of these structures by small mammals and their predators could result in increased predation rates in these passages or lead small mammals to avoid using them. This would be particularly harmful to small populations or threatened species such as the European hamster (Cricetus cricetus). To overcome this problem and to provide lateral escape opportunities along the length of the underpasses, we developed
an anti-predation tube. We tested the features (shape and size) of this device under laboratory conditions and validated its use by captive European hamsters. Our results reveal that the optimal anti-predation
tube has a diameter of 10 cm, a curved shape and lateral openings. This device will be tested under field conditions to validate its efficiency to protect small mammals using wildlife underpasses. If confirmed,
this system could considerably improve crossing conditions in bigger tunnels and on bridges such as agricultural under- or overpasses, which have been unsuitable for small animals until now.
Une restauration partielle par les passages à faune des continuités écologiques pour les micromammifères a été mise en évidence. En effet, les seules sections routières sur lesquelles des individus traversant la route ont été observés étaient celles équipées d’un passage à faune. Cependant, la probabilité de dispersion d’un côté à l’autre de la route serait trop faible pour assurer, à elle-seule, un brassage génétique suffisant. Ainsi, dans un objectif de conservation des espèces, une amélioration des passages à faune pour les micromammifères est nécessaire.
We explored 182 abandoned bunkers in a farmland area in eastern France in summer 2016. Bunkers were located in crops, forests, or groves. Over a three-month period, signs of presence, the number and type of burrows inside the bunkers and in their immediate vicinity were noted. Environmental variables were obtained using GIS, and binomial models were created to reveal parameters influencing bunker use by badgers and foxes. The degree of bunkers burrowing was used as a co-variable. Twenty-one groves without bunkers were also studied in order to estimate the added value of bunkers in groves.
Badger and fox tracks were found on 34% of the sites, and burrows on 24% of them with similar rates for badgers and foxes. Animals used partially buried bunkers more than underground or overground bunkers. The sizes of annual crops and urban areas around the bunker were positively correlated with bunker use. The presence of a bunker in groves was positively correlated with the presence of burrows in groves.
K E Y W O R D S camera trapping, false trigger, monitoring study, small mammals, triggered cameras, wildlife crossings
Thesis Chapters by Jonathan Jumeau
In this essay are shown (1) the potential as habitat of different road-linked elements; (2) the possibility to anticipate wildlife-vehicles collisions in order to improve the position of mitigation measures; (3) the importance of methodology in the evaluation of wildlife crossings effectiveness; and (4) the possibility to improve existing wildlife crossings.
Those results will allow improving landscape defragmentation strategies
Conference Presentations by Jonathan Jumeau
However, few studies have investigated the efficiency of these devices to systematically and automatically capture a majority of the passage events (PE), or their impact on wildlife passages frequentation. How many animals are missed by the device? Is the reliability dependent on type of species ? What are the best sensors’ parameters? Is there an impact of the devices on animals’ behavior? How many days are needed to make a sufficient survey of an underpass? These are the questions we asked to improve the knowledge in triggered camera utilization.
From April 2012 to June 2013, we monitored 12 underpasses located in Alsace (East France) with both triggered photographic cameras (Reconyx HC600) and video cameras. Video cameras recorded 24 hours a day and 7 days per week in order to observe all PE of all species and identify every event missed by triggered cameras configured in 5 different motion/thermal ratios. The behavior of carnivores was recorded in order to assess possible disturbance by the devices on the animals. Finally, we performed a correlation between the number of monitoring days and the diversity of species observed.
We found that in small box culverts, 47% of small mammals (voles, mice, shrews) PE and 17% of medium-sized mammals PE (foxes, badgers and other mustelids) are missed by triggered cameras. Moreover, we demonstrated that whatever the season, motion/thermal ratios favoring the motion sensor missed less events than ratios favoring the thermal sensor. Despite every species likely to use our culverts are detected, we found that a minimum of five months were needed to detect 90% of the overall specific diversity over the study period, 3 months more than the duration recommended in previous studies. Monitoring devices disrupted medium-sized mammals during the first five weeks after their installation. There were also fewer carnivores the night after our presence on the field to replace batteries and memory cards.
Even by using the latest technologies, our results point out a significant underestimation of wildlife passage utilization which can introduce an important bias to conclusions about effectiveness of faunal passage structures.
When a road is built, potential substitution environments (named road bound landscape elements or RBLE) appear like (1) road verges, (2) storm-water basins, (3) excavation slopes or even (4) middle of roundabouts. Indeed, road verges are for example well known to be habitats for some butterflies, orchids or rodents and storm-water basins are frequently occupied by amphibians or birds. However, the habitat potentiality of all RBLE is not known and even if they could be beneficial for the environment, such hypothesis is not considered during current road environmental studies. Thus, to study the ability of RBLE to be suitable habitats, we have compared these 4 RBLE to two different usual crops fields of corn and wheat. Four replicates of these 6 different habitats were selected in an intensive farming landscape.
To characterize differences in habitat quality, indexes of rodents populations abundance (capture-mark-recapture) and qualities (body condition and survival based on Huggin’s Robust Design model) have been investigated. The study was conducted from May 2015 to August 2015 with 4 captures sessions of 4 consecutive days.
We captured 3166 micromammals with an average of 66 individuals per day. These individuals were distributed in four different species: wood mouse (Apodemus sylvaticus), bank vole (Myodes glareolus), commun vole (Microtus arvalis) and Greater white-toothed shrew (Crocidura russula). Following results concern Microtus arvalis only. We found a greater abundance of individuals in every RBLE than in controls (7.5 times more in average), with almost no individuals in corn crops (< 2 per studied crop). This effect is even stronger in July when wheat crops are mown (0,2 individuals/m² in RLBE vs 0,006 individuals/m² in controls). There is also no significant difference in terms of survival and body condition index between sites with sufficient captured individuals (RLBE and wheat corn only).
These results lead us to consider all road bund landscapes elements (not only road verges) as sustainable habitats which can favor both rodents (and probably shrews too) and predators communities. However, the respective advantages (rodent vs predators) may be difficult to consider in the light of the Predation Release Hypothesis: i.e. a small number of predators will profit of these RBL habitats.
We recommend taking account damages these rodents can cause to nearest crops (financial compensations to farmers), road hedgerows (plants protections, fences) and structures like basins during roads environmental impact studies and road conception, particularly in years of great rodent abundance. Finally, if the rodents’ abundances in RBLE have to be decreased, the employed methods need to be considered in the light of other RBLE taxa such as butterflies and orchids.
partitioning measures are installed to prevent animals to access to them. In a context of intensive farming landscape, land consolidation has led to the removal of most wetlands. Moreover, as basins are potential habitats for species deprived of their environments, it is not rare to find animal communities into the basins, including amphibian, particularly sensitive to pollutants. The effectiveness and relevance of partitioning measures designed to stop amphibians from
entering the basins is thus questioned regarding their impact on amphibians development. The richness and abundance of amphibians were collected using POPamphibian protocol on more than eighty stormwater and natural ponds. Explanatory variables are water physicochemical parameters including levels of pollution, surrounding land use (like suitable habitats and corridors) and characteristics of basin including partitioning measures. Amphibians have been found in most basins at different stages of development, so partitioning measures do not seem effective. No effect of pollution level was observed. The surrounding environment is the best predictive variable of presence of breeding. However, it is difficult to attribute the decline of the offspring to pollution or natural predation pressure. In conclusion, partitioning measures are neither effective nor relevant in the context of an intensive farming landscape. We invite roads manager to remove partitioning measures from stormwater ponds or/and to create substitution puddles close to them.
of these structures by small mammals and their predators could result in increased predation rates in these passages or lead small mammals to avoid using them. This would be particularly harmful to small populations or threatened species such as the European hamster (Cricetus cricetus). To overcome this problem and to provide lateral escape opportunities along the length of the underpasses, we developed
an anti-predation tube. We tested the features (shape and size) of this device under laboratory conditions and validated its use by captive European hamsters. Our results reveal that the optimal anti-predation
tube has a diameter of 10 cm, a curved shape and lateral openings. This device will be tested under field conditions to validate its efficiency to protect small mammals using wildlife underpasses. If confirmed,
this system could considerably improve crossing conditions in bigger tunnels and on bridges such as agricultural under- or overpasses, which have been unsuitable for small animals until now.
Une restauration partielle par les passages à faune des continuités écologiques pour les micromammifères a été mise en évidence. En effet, les seules sections routières sur lesquelles des individus traversant la route ont été observés étaient celles équipées d’un passage à faune. Cependant, la probabilité de dispersion d’un côté à l’autre de la route serait trop faible pour assurer, à elle-seule, un brassage génétique suffisant. Ainsi, dans un objectif de conservation des espèces, une amélioration des passages à faune pour les micromammifères est nécessaire.
We explored 182 abandoned bunkers in a farmland area in eastern France in summer 2016. Bunkers were located in crops, forests, or groves. Over a three-month period, signs of presence, the number and type of burrows inside the bunkers and in their immediate vicinity were noted. Environmental variables were obtained using GIS, and binomial models were created to reveal parameters influencing bunker use by badgers and foxes. The degree of bunkers burrowing was used as a co-variable. Twenty-one groves without bunkers were also studied in order to estimate the added value of bunkers in groves.
Badger and fox tracks were found on 34% of the sites, and burrows on 24% of them with similar rates for badgers and foxes. Animals used partially buried bunkers more than underground or overground bunkers. The sizes of annual crops and urban areas around the bunker were positively correlated with bunker use. The presence of a bunker in groves was positively correlated with the presence of burrows in groves.
K E Y W O R D S camera trapping, false trigger, monitoring study, small mammals, triggered cameras, wildlife crossings
In this essay are shown (1) the potential as habitat of different road-linked elements; (2) the possibility to anticipate wildlife-vehicles collisions in order to improve the position of mitigation measures; (3) the importance of methodology in the evaluation of wildlife crossings effectiveness; and (4) the possibility to improve existing wildlife crossings.
Those results will allow improving landscape defragmentation strategies
However, few studies have investigated the efficiency of these devices to systematically and automatically capture a majority of the passage events (PE), or their impact on wildlife passages frequentation. How many animals are missed by the device? Is the reliability dependent on type of species ? What are the best sensors’ parameters? Is there an impact of the devices on animals’ behavior? How many days are needed to make a sufficient survey of an underpass? These are the questions we asked to improve the knowledge in triggered camera utilization.
From April 2012 to June 2013, we monitored 12 underpasses located in Alsace (East France) with both triggered photographic cameras (Reconyx HC600) and video cameras. Video cameras recorded 24 hours a day and 7 days per week in order to observe all PE of all species and identify every event missed by triggered cameras configured in 5 different motion/thermal ratios. The behavior of carnivores was recorded in order to assess possible disturbance by the devices on the animals. Finally, we performed a correlation between the number of monitoring days and the diversity of species observed.
We found that in small box culverts, 47% of small mammals (voles, mice, shrews) PE and 17% of medium-sized mammals PE (foxes, badgers and other mustelids) are missed by triggered cameras. Moreover, we demonstrated that whatever the season, motion/thermal ratios favoring the motion sensor missed less events than ratios favoring the thermal sensor. Despite every species likely to use our culverts are detected, we found that a minimum of five months were needed to detect 90% of the overall specific diversity over the study period, 3 months more than the duration recommended in previous studies. Monitoring devices disrupted medium-sized mammals during the first five weeks after their installation. There were also fewer carnivores the night after our presence on the field to replace batteries and memory cards.
Even by using the latest technologies, our results point out a significant underestimation of wildlife passage utilization which can introduce an important bias to conclusions about effectiveness of faunal passage structures.
When a road is built, potential substitution environments (named road bound landscape elements or RBLE) appear like (1) road verges, (2) storm-water basins, (3) excavation slopes or even (4) middle of roundabouts. Indeed, road verges are for example well known to be habitats for some butterflies, orchids or rodents and storm-water basins are frequently occupied by amphibians or birds. However, the habitat potentiality of all RBLE is not known and even if they could be beneficial for the environment, such hypothesis is not considered during current road environmental studies. Thus, to study the ability of RBLE to be suitable habitats, we have compared these 4 RBLE to two different usual crops fields of corn and wheat. Four replicates of these 6 different habitats were selected in an intensive farming landscape.
To characterize differences in habitat quality, indexes of rodents populations abundance (capture-mark-recapture) and qualities (body condition and survival based on Huggin’s Robust Design model) have been investigated. The study was conducted from May 2015 to August 2015 with 4 captures sessions of 4 consecutive days.
We captured 3166 micromammals with an average of 66 individuals per day. These individuals were distributed in four different species: wood mouse (Apodemus sylvaticus), bank vole (Myodes glareolus), commun vole (Microtus arvalis) and Greater white-toothed shrew (Crocidura russula). Following results concern Microtus arvalis only. We found a greater abundance of individuals in every RBLE than in controls (7.5 times more in average), with almost no individuals in corn crops (< 2 per studied crop). This effect is even stronger in July when wheat crops are mown (0,2 individuals/m² in RLBE vs 0,006 individuals/m² in controls). There is also no significant difference in terms of survival and body condition index between sites with sufficient captured individuals (RLBE and wheat corn only).
These results lead us to consider all road bund landscapes elements (not only road verges) as sustainable habitats which can favor both rodents (and probably shrews too) and predators communities. However, the respective advantages (rodent vs predators) may be difficult to consider in the light of the Predation Release Hypothesis: i.e. a small number of predators will profit of these RBL habitats.
We recommend taking account damages these rodents can cause to nearest crops (financial compensations to farmers), road hedgerows (plants protections, fences) and structures like basins during roads environmental impact studies and road conception, particularly in years of great rodent abundance. Finally, if the rodents’ abundances in RBLE have to be decreased, the employed methods need to be considered in the light of other RBLE taxa such as butterflies and orchids.
partitioning measures are installed to prevent animals to access to them. In a context of intensive farming landscape, land consolidation has led to the removal of most wetlands. Moreover, as basins are potential habitats for species deprived of their environments, it is not rare to find animal communities into the basins, including amphibian, particularly sensitive to pollutants. The effectiveness and relevance of partitioning measures designed to stop amphibians from
entering the basins is thus questioned regarding their impact on amphibians development. The richness and abundance of amphibians were collected using POPamphibian protocol on more than eighty stormwater and natural ponds. Explanatory variables are water physicochemical parameters including levels of pollution, surrounding land use (like suitable habitats and corridors) and characteristics of basin including partitioning measures. Amphibians have been found in most basins at different stages of development, so partitioning measures do not seem effective. No effect of pollution level was observed. The surrounding environment is the best predictive variable of presence of breeding. However, it is difficult to attribute the decline of the offspring to pollution or natural predation pressure. In conclusion, partitioning measures are neither effective nor relevant in the context of an intensive farming landscape. We invite roads manager to remove partitioning measures from stormwater ponds or/and to create substitution puddles close to them.