Rodent Pests Research Articles

Multi-scale analysis of barn owl nest box selection on Napa Valley vineyards

Abstract Barn owls ( Tyto alba ) have the potential to remove significant numbers of rodent pests in vineyards, which has prompted viticulturists in California to erect artificial nest boxes to attract owls. This study examined the habitat factors influencing barn owl nest box occupancy as well as farmers’ perceptions of barn owls in vineyards in Napa Valley, CA. Nest boxes of variable design and placement were distributed across 65 vineyards that varied in local and landscape habitat composition. We monitored 297 nest boxes in 2015 to develop an occupancy model. We evaluated the performance of the 2015 model by revisiting 150 boxes in 2016 and comparing observed occupancy to the predicted probability of occupancy for each nest box. Barn owls occupied approximately one third of the nest boxes we monitored each year. We used variance decomposition to address cross scale correlations among three nested spatial scales and to analyze the variation in nest box occupancy explained uniquely by predictors at each spatial scale. The home range and nest box scales were the most important spatial scales. At the home range scale, barn owls selected nest boxes surrounded by more hectares of grassland, riparian and mixed forest, and fewer hectares of oak scrub within 1 km of the box. Owls were more likely to occupy nest boxes if they were constructed of wood, facing north and positioned higher off the ground. The model developed in 2015 performed well in 2016, correctly classifying 81.3% of the boxes, and the area under the receiver operating characteristic curve was 0.86. In addition, we surveyed farmers to gauge their perceptions of the utility of barn owls as a component of an integrated pest management scheme in winegrape vineyards. The majority of farmers surveyed installed barn owl nest boxes for the perceived pest management services instead of the potential positive public appeal of improving barn owl habitat.

A method for reducing environmental pollution by using essential oils in rodent pest management program.

Strong-smelling plant extracts, such as essential oils, have a variety of feeding effects on mammals. Considering current concerns over long-term health issues and environmental effects of chemicals, plant-based products with repellent or antifungal activities may represent good solutions for improvement of rodent pest control programs. The present study was therefore focused on examining the effects of bergamot, lavender, and thyme essential oils as additional bait components on daily intakes of cereal-based baits by wild house mice. Lavender essential oil, containing linalool and linalyl acetate as main components, and thyme essential oil with a prevailing thymol component had no effects on house mice diet. Bergamot essential oil, whose main components were linalool, limonene, and linalyl acetate, showed a repellent effect on house mouse diet.

Spatial modelling of non-target exposure to anticoagulant rodenticides can inform mitigation options in two boreal predators inhabiting areas with intensive oil and gas development

Intensive industrial development occurs in the ecologically significant boreal forest, including oil and gas development in northern Alberta, Canada. This forest is home to many highly-valued animal species including fisher (Pekania pennanti; formerly Martes pennanti) and American marten (Martes americana). Second-generation anticoagulant rodenticides (SGARs) are commonly used near human infrastructure in developed areas to control and reduce damage from rodent pests. High body burdens of SGARs in rodent prey pose risks of secondary poisoning for fisher and marten that readily consume rodents. The objective of this research was to determine if fisher and marten living in anthropogenically-disturbed areas of northern Alberta showed evidence of SGAR exposure. Fisher and marten carcasses were collected from the region, aged, sexed, and liver samples were analysed for rodenticides using liquid-chromatography mass spectrometry (LCMS). SGARs were found in the livers of non-target fisher and marten. As SGARs were found in the livers of fisher with sufficient frequency for complete statistical analysis, analyses including ANOVA, linear regression, and spatial cluster analyses were used to assess spatial patterns exhibited by fisher exposure frequencies against potential explanatory variables such as boreal anthropogenic disturbances and land cover classes. Additionally, companies operating in the region were surveyed to identify their current rodent control measures in an effort to verify the results of the spatial analyses. This is the first study to demonstrate non-target SGAR exposure of fisher and marten in Canada. Exposure frequency in fisher exhibited clustering, which showed the strongest relationships to factors including total boreal disturbances, number of oil sands mines, and broadleaf forest cover. The spatial methods used in this paper provide tools to develop local interventions for mitigation and conservation efforts.

English

The paper examines gender-based strategies to fill income gaps in Adi E’re, Ethiopia. In the parish, crop production is vulnerable to a multitude of challenges. Shortage of rainfall, locust plagues and rodent pests are seriously damaged a potential good harvest. In addition, farming activities is underperforming due to a relatively low technological level. For details on the factors associated to low crop production in the rural Tigray, see the work of Bauer. These are some of the factors that are affecting income generation in many households. As a result, they are often tried to address temporal deficits in grain production through strong gender-oriented strategies. The findings reveal that women have long played and continue to play an important role in the course of annual crop management and food security. Contrary to general perception, women in Adi E’re are not merely circumscribed in processing and preparing food, collecting fuel and water, and caring for family but they are part of the wider practice of resource management and socio-economic interdependency. They are not merely contributing to stretch grain supply as far as possible, but also to maintain the household from economic bankruptcy and dispersal. The present study is, therefore, not only aimed to affirm the indispensable contribution of women in filling income gaps, but also to devalue prejudicial works. The study attempts to consult a plethora of primary and secondary sources. Both men and women living in the parish are extensively interviewed. The sources are significantly collected, scrutinized and analyzed. The validities of the sources are cross-checked one against the other. Key words: Gender, income gaps, survival strategy, interdependency.

Recovery of fertility in quinestrol-treated or diethylstilbestrol-treated mice: Implications for rodent management.

Fertility control is an alternative strategy to traditional culling for the management of rodent pests. Previous studies have demonstrated that quinestrol is a potential contraceptive for male rodents, but the recovery of fertility in quinestrol-treated rodents has not been evaluated. This study used C57BL/6J mice to evaluate the recovery rate of male fertility after the administration of quinestrol. Diethylstilbestrol (DES), a non-steroid estrogenic compound, was used for comparison. Different groups of mice were treated with 1 mg/kg quinestrol, 1 mg/kg DES, or castor oil separately for 7 days. These mice were then killed on days 8, 22 and 50 respectively. Our results indicated that the weight of epididymides and seminal vesicles decreased significantly on days 8 and 22 in quinestrol/DES-treated mice, with extensive histological changes in the seminiferous tubules. Sperm concentrations in the cauda epididymal fluid were significantly reduced on days 8 and 22 in both quinestrol and DES treatment groups and on day 50 for the DES, but not the quinestrol group. Further analysis revealed that DES-treated mice exhibited a higher proportion of abnormal sperm accumulation in the epididymis, indicating that the normal sperm transportation to the cauda epididymis was blocked. Our results indicate that the anti-fertility effects on male mice given quinestrol were of shorter duration than for those receiving DES at the dose of 1 mg/kg body weight.

A systematic review of rodent pest research in Afro-Malagasy small-holder farming systems: Are we asking the right questions?

Rodent pests are especially problematic in terms of agriculture and public health since they can inflict considerable economic damage associated with their abundance, diversity, generalist feeding habits and high reproductive rates. To quantify rodent pest impacts and identify trends in rodent pest research impacting on small-holder agriculture in the Afro-Malagasy region we did a systematic review of research outputs from 1910 to 2015, by developing an a priori defined set of criteria to allow for replication of the review process. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We reviewed 162 publications, and while rodent pest research was spatially distributed across Africa (32 countries, including Madagascar), there was a disparity in number of studies per country with research biased towards four countries (Tanzania [25%], Nigeria [9%], Ethiopia [9%], Kenya [8%]) accounting for 51% of all rodent pest research in the Afro-Malagasy region. There was a disparity in the research themes addressed by Tanzanian publications compared to publications from the rest of the Afro-Malagasy region where research in Tanzania had a much more applied focus (50%) compared to a more basic research approach (92%) in the rest of the Afro-Malagasy region. We found that pest rodents have a significant negative effect on the Afro-Malagasy small-holder farming communities. Crop losses varied between cropping stages, storage and crops and the highest losses occurred during early cropping stages (46% median loss during seedling stage) and the mature stage (15% median loss). There was a scarcity of studies investigating the effectiveness of various management actions on rodent pest damage and population abundance. Our analysis highlights that there are inadequate empirical studies focused on developing sustainable control methods for rodent pests and rodent pests in the Africa-Malagasy context is generally ignored as a research topic.

Adaptative evolution of the Vkorc1 gene in Mus musculus domesticus is influenced by the selective pressure of anticoagulant rodenticides.

Anticoagulant rodenticides are commonly used to control rodent pests worldwide. They specifically inhibit the vitamin K epoxide reductase (VKORC1), which is an enzyme encoded by the Vkorc1 gene, involved in the recycling of vitamin K. Therefore, they prevent blood clotting. Numerous mutations of Vkorc1 gene were reported in rodents, and some are involved in the resistant to rodenticides phenotype. Two hundred and sixty‐six mice tails were received from 65 different locations in France. Coding sequences of Vkorc1 gene were sequenced in order to detect mutations. Consequences of the observed mutations were evaluated by the use of recombinant VKORC1. More than 70% of mice presented Vkorc1 mutations. Among these mice, 80% were homozygous. Contrary to brown rats for which only one predominant Vkorc1 genotype was found in France, nine missense single mutations and four double mutations were observed in house mice. The single mutations lead to resistance to first‐generation antivitamin K (AVKs) only and are certainly associated with the use of these first‐generation molecules by nonprofessionals for the control of mice populations. The double mutations, probably obtained by genetic recombination, lead to in vitro resistance to all AVKs. They must be regarded as an adaptive evolution to the current use of second‐generation AVKs. The intensive use of first‐generation anticoagulants probably allowed the selection of a high diversity of mutations, which makes possible the genetic recombination and consequently provokes the emergence of the more resistant mutated Vkorc1 described to date.

Domestic cats and dogs create a landscape of fear for pest rodents around rural homesteads.

Using domestic predators such as cats to control rodent pest problems around farms and homesteads is common across the world. However, practical scientific evidence on the impact of such biological control in agricultural settings is often lacking. We tested whether the presence of domestic cats and/or dogs in rural homesteads would affect the foraging behaviour of pest rodents. We estimated giving up densities (GUDs) from established feeding patches and estimated relative rodent activity using tracking tiles at 40 homesteads across four agricultural communities. We found that the presence of cats and dogs at the same homestead significantly reduced activity and increased GUDs (i.e. increased perception of foraging cost) of pest rodent species. However, if only cats or dogs alone were present at the homestead there was no observed difference in rodent foraging activity in comparison to homesteads with no cats or dogs. Our results suggest that pest rodent activity can be discouraged through the presence of domestic predators. When different types of predator are present together they likely create a heightened landscape of fear for foraging rodents.

Perceptions of rodent-associated problems: an experience in urban and rural areas of Yucatan, Mexico

Rodents are a threat to agriculture and homes, and are a public health risk. Local perceptions about rodents and the damage they cause are vital, as a first step, to the design and implementation of rodent control or educational programs. A total of 111 interviews were conducted in two urban neighborhoods and two rural villages in Yucatan, Mexico. More than 90% of the interviewed inhabitants perceived rodents as a problem. The fear of rodents (57%), damage to food and stocks (56%), and damage to clothes (34%), were the most cited problems. In the urban neighborhoods, the use of rodent control methods was more frequent (57%) than in the villages (33%) in this study. In addition, the percentage of damage to domestic appliances was lower in villages (10%) than in neighborhoods (33%). Our preliminary results suggest that rodent pests represent a threat to human health and to human food security in the studied sites.

Rodent management issues in South Pacific islands: a review with case studies from Papua New Guinea and Vanuatu

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers. The rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.

Ecology of phlebotomine sandflies and putative reservoir hosts of leishmaniasis in a border area in Northeastern Mexico: implications for the risk of transmission of Leishmania mexicana in Mexico and the USA.

Leishmaniases are a group of important diseases transmitted to humans through the bite of sandfly vectors. Several forms of leishmaniases are endemic in Mexico and especially in the Southeast region. In the Northeastern region, however, there have only been isolated reports of cases and scanty records of sandfly vectors. The main objective of this study was to analyze the diversity of sandflies and potential reservoir hosts of Leishmania spp. in the states of Nuevo León and Tamaulipas. Species richness and abundances of sandflies and rodents were recorded. A fraction of the caught sandflies was analyzed by PCR to detect Leishmania spp. Tissues from captured rodents were also screened for infection. Ecological Niche Models (ENMs) were computed for species of rodent and their association with crop-growing areas. We found 13 species of sandflies, several of which are first records for this region. Medically important species such as Lutzomyia anthophora, Lutzomyia diabolica, Lutzomyia cruciata, and Lutzomyia shannoni were documented. Leishmania spp. infection was not detected in sandflies. Nine species of rodents were recorded, and Leishmania (Leishmania) mexicana infection was found in four species of Peromyscus and Sigmodon. ENMs showed that potential distribution of rodent pest species overlaps with allocated crop areas. This shows that Leishmania (L.) mexicana infection is present in the Northeastern region of Mexico, and that previously unrecorded sandfly species occur in the same areas. These findings suggest a potential risk of transmission of Leishmania (L.) mexicana.

Reliability of methods used to estimate rodent pest densities in agricultural systems: the case of common vole (Microtus arvalis) in NW Spain

For pest management strategies to effectively prevent crop damage while at the same time causing the least environmental collateral damage, reliable abundance monitoring tools are required. The common vole is a major agricultural pest in Castilla y León (NW Spain). In this study we compared common vole density estimates provided by two indirect indices, the Presence Signs per Square (PSpS) index, previously evaluated by a comparison with the trapping methodology most accepted to estimate rodent densities, and another one (MI), proposed by the Spanish Ministry of Agriculture Food and Environment, which is currently recommended as main monitoring tool for this pest, but that apparently has not been evaluated in a similar way. We found that at low vole abundance, MI generated much larger vole density estimates (on average 14 times) as compared to PSpS, although both indices were highly correlated. These results strongly support that abundance estimates provided by MI must be considered potential overestimates of real vole density and must be corrected accordingly in the future, if the method is to be kept as a main monitoring tool of vole density. Our results reinforce the importance of evaluating this kind of monitoring tools in different density scenarios to prevent the start or continuation of control campaigns when they are unnecessary, thus reducing their associated economic and environmental costs.

Yield and Income Effects of Ecologically-based Rodent Management in Mekong River Delta, Vietnam

Regression-based strategies along with propensity score matching (PSM) were used to assess the farm-level economic impact of community action (CA) strategies associated with ecologically based rodent management (EBRM). The paddy yield and real net income of rice farmer beneficiaries of the EBRM approach in An Giang Province, Mekong River Delta, Vietnam, were analyzed using panel data from 151 rice farmers. PSM along with the difference-indifference framework using the fixed-effect approach were found to be the most appropriate methods to evaluate the farm-level economic impact of the adoption of the CA strategies. The EBRM through CA did not replace what the farmers were doing, but rather built on their practices and incorporated a scientific basis by encouraging farmers to work together at key times of a cropping season. In terms of labor use for rodent control, CA only entailed an additional 0.3 man-days/ha for every CA. Normally, for a 40-hectare (ha) rice field, around 30 persons participated in each CA including men, women, and children. With two to three times done in a season, a total of 1 man-day/ha is as an additional labor for the whole season. The adoption of the EBRM through CA had a significant and positive impact on paddy yield and real net income of rice farmers. The mean paddy yield increased by 0.43-0.45 ton per ha and real net income of the beneficiaries increased by VND1.16–1.19 million/ha (approximately USD65-67/ha). These findings imply that the adoption of the CA strategies in rodent pest management as part of EBRM may not only have partly contributed to food security and increased household income of the rice farmer-beneficiaries but also to environmental improvement in these communities.

Behavioral Response of Multimammate Rat (Mastomys Natalensis, Smith 1834) on Selected Crude Pesticidal Plant Extracts

A plus maze arrangement was set at the Rodent Control Centre, Morogoro, Tanzania to investigate the rat behavior when subjected to maize seeds dressed with crude extracts of Lantana camara leaves (200 g), Ricinus communis seeds (150 g) and Euphorbia candelabrum latex (300 ml). The choice and no-choice test were set using a group of ten rats (5M+ 5F) in five plastic buckets. Each plastic bucket was fixed with RECONIX camera trap on top for picture capturing. Animals were provided with drinking water at the center bucket. In each experiment observation was made for four consecutive days where maize damaged seed, rat activities type (feeding, walking, resting, playing, sentry, grooming, biting others and approaching food) data were daily recorded. Results revealed that there was significant difference (p=0.00001) in maize damaged seed between treatments. With regards to nocturnal behavior, significant difference between treated and control on L. camara leaf (p=0.01301) and R. communis seed (p less than 0.00001) with no significant effect on E. candelabrum latex (p=0.93254) was observed. “Authors are grateful to the financial support provided by the Commission for Science and Technology (COSTECH), Tanzania that enabled accomplishment of this work.” No significant difference between treatments on the proportion of rat pictures approaching food (p=0.64821), biting each other (p = 0.91205), grooming (p=0.59964), feeding (p=0.27042), playing (p=0.36140), sentry (p=0.819821) and walking (p=0.06749). However, there was a significant difference on resting (p=0.02998). In general, this study recommends the use of R. communis for management of M. natalensis in maize farming system due low number of maize damaged seeds. However, several key questions remain, the most urgent being to extract the active compounds responsible for efficacy against rodent pest.

EVALUATING THE EFFICACY OF THE MALE CHEMOSTERILANT ALPHA-CHLOROHYDRIN ON THREE EGYPTIAN WILD RODENT PESTS UNDER LABORATORY CONDITIONS

The current study was designed to evaluate the efficacy of the male chemosterilant alpha-chlorohydrin (ACH) in the control of three Egyptian wild rodent pests (Order: Rodentia, Family: Muridae), namely; the Cairo spiny mouse, Acomys cahirinus (Desmarest, 1819) the lesser Egyptian gerbil, Gerbillus gerbillus (Olivier, 1801) and Shaw’s jird, Meriones shawi Rozet, 1833. The effect of ACH was tested by the examination of the relative weights of the reproductive organs, the sperm parameters, as well as the histological alterations in the testis and epididymis. The results of this study showed that ACH has no significant antifertility effect when given to A. cahirinus at doses of 50 mg/kg body weight for 5 days, 70 mg/kg for 4 days; to G. gerbillus at doses of 50 mg/kg for 3 days, and 60 mg/kg for 4 days; and to M. shawi at doses of 50 mg/kg for 5 days, and 80 mg/kg for 3 days. Taken together, it could be concluded that ACH has a species-specific action, and is not recommended to be used in the control of the rodent pests of the present study.

English

A quantitative study was conducted in the Eastern zone of Tanzania, from May to September 2012 to assess farmers’ knowledge, altitude and practice on the use of locally available plant materials for controlling rodent damage in maize fields and stores. Three villages in three districts were purposively selected with a total of 270 farmers randomly selected for the interview. A semi structured questionnaire was used to assess maize production constraints. Rodent pests were ranked higher (56%) than other pests with their crop losses estimated to be 64 and 36% in fields and stores, respectively. Use of rodenticides for rodent control was reported as the common single method. However, 85% of farmers use rodenticides with inadequate knowledge on application and their effects on the environment and health. It was further revealed that only 15% of the respondents reported to have attained training on how to apply rodenticides. With regard to the use of locally available plants, 4% of respondents reported to use them for rodent control, while 96% were not aware of any plant that was effective against rodents. However, most (97%) respondents expressed their willingness to use plant materials if provided with evidence that they are effective. Therefore, evaluation of plant materials and consequent development of plant products which can be safely used by poor resource farmers and subsequently reduce health and environmental risks associate with chemical rodenticides was recommended.   Key words: Rodents, plant materials, maize, Tanzania.

Analisis Perbandingan Pendapatan Petani Pola Tanam Monokultur Dan Polikultur Di Kecamatan Meureudu Kabupaten Pidie Jaya

In the District Meureudu, there are two types of cropping farming in paddy fields, namely Monoculture cropping pattern and cropping patterns poly. Monoculture is planting only one crop a year, namely rice, whereas polyculture cropping is planting more than one plant within a year, namely rice and soybeans. The method used in this research is survey method. The sampling technique is cluster sampling and data used are primary data and secondary data. Average - Average area of land that did monoculture is 0.22 hectares, while the area of land on the cropping pattern polyculture is 0.15. Average - Average harvests of farmers practicing monoculture of 3.2 ton / year, while the average - average yields in cropping patterns polyculture 1.9 ton / year for rice and 0.48 Kg / year for soybeans. Comparison of farmers using monoculture and polyculture in District Meureudu is 65: 35. In general, farmers in Sub Meureudu that uses monoculture earn 42 million / ha / year, while the use of polyculture cropping patterns to earn 58 million / ha / Year. Constraints faced by farmers practicing monoculture of the interview that the pest rodents, sparrows and waterways, while the polyculture cropping patterns from the interviews that the pest rodents, sparrows, waterways and livestock citizens. Keywords: Income, monoculture, and poly

Structural elucidation of estrus urinary lipocalin protein (EULP) and evaluating binding affinity with pheromones using molecular docking and fluorescence study

Transportation of pheromones bound with carrier proteins belonging to lipocalin superfamily is known to prolong chemo-signal communication between individuals belonging to the same species. Members of lipocalin family (MLF) proteins have three structurally conserved motifs for delivery of hydrophobic molecules to the specific recognizer. However, computational analyses are critically required to validate and emphasize the sequence and structural annotation of MLF. This study focused to elucidate the evolution, structural documentation, stability and binding efficiency of estrus urinary lipocalin protein (EULP) with endogenous pheromones adopting in-silico and fluorescence study. The results revealed that: (i) EULP perhaps originated from fatty acid binding protein (FABP) revealed in evolutionary analysis; (ii) Dynamic simulation study shows that EULP is highly stable at below 0.45 Å of root mean square deviation (RMSD); (iii) Docking evaluation shows that EULP has higher binding energy with farnesol and 2-iso-butyl-3-methoxypyrazine (IBMP) than 2-naphthol; and (iv) Competitive binding and quenching assay revealed that purified EULP has good binding interaction with farnesol. Both, In-silico and experimental studies showed that EULP is an efficient binding partner to pheromones. The present study provides impetus to create a point mutation for increasing longevity of EULP to develop pheromone trap for rodent pest management.

Rate of exposure of a sentinel species, invasive American mink (Neovison vison) in Scotland, to anticoagulant rodenticides

Anticoagulant rodenticides (ARs) are highly toxic compounds that are exclusively used for the control of rodent pests. Despite their defined use, they are nonetheless found in a large number of non-target species indicating widespread penetration of wildlife. Attempts to quantify the scale of problem are complicated by non-random sampling of individuals tested for AR contamination. The American mink (Neovison vison) is a wide ranging, non-native, generalist predator that is subject to wide scale control efforts in the UK. Exposure to eight ARs was determined in 99 mink trapped in NE Scotland, most of which were of known age. A high percentage (79%) of the animals had detectable residues of at least one AR, and more than 50% of the positive animals had two or more ARs. The most frequently detected compound was bromadiolone (75% of all animals tested), followed by difenacoum (53% of all mink), coumatetralyl (22%) and brodifacoum (9%). The probability of mink exposure to ARs increased by 4.5% per month of life, and was 1.7 times higher for mink caught in areas with a high, as opposed to a low, density of farms. The number of AR compounds acquired also increased with age and with farm density. No evidence was found for sexual differences in the concentration and number of ARs. The wide niche and dietary overlap of mink with several native carnivore species, and the fact that American mink are culled for conservation throughout Europe, suggest that this species may act as a sentinel species, and the application of these data to other native carnivores is discussed.

Landscape determinants of fine-scale genetic structure of a small rodent in a heterogeneous landscape (Hluhluwe-iMfolozi Park, South Africa)

Small mammals provide ecosystem services, acting, for example, as pollinators and seed dispersers. In addition, they are also disease reservoirs that can be detrimental to human health and they can also act as crop pests. Knowledge of their dispersal preferences is therefore useful for population management and landscape planning. Genetic data were used alongside landscape data to examine the influence of the landscape on the demographic connectedness of the Natal multimammate mouse (Mastomys natalensis) and to identify landscape characteristics that influence the genetic structure of this species across a spatially and temporally varying environment. The most significant landscape features shaping gene flow were aspect, vegetation cover, topographic complexity (TC) and rivers, with western facing slopes, topographic complexity and rivers restricting gene flow. In general, thicket vegetation was correlated with increased gene flow. Identifying features of the landscape that facilitate movement/dispersal in M. natalensis potentially has application for other small mammals in similar ecosystems. As the primary reservoir host of the zoonotic Lassa virus, a landscape genetics approach may have applications in determining areas of high disease risk to humans. Identifying these landscape features may also be important in crop management due to damage by rodent pests.