Wildlife Food Research Articles

High foraging efficiency of Eurasian otters in a shallow Iberian reservoir

The anthropic transformation of the landscape has brought the arrival of novel ecosystems. Since these ecosystems will likely become increasingly common in the future it is important to know if they can provide food for wildlife. Here we test whether European otters Lutra lutra can have high foraging success in human-made reservoirs. Rhythms of daily activity were studied in a small (365 ha) and shallow (6–15 m) reservoir in NW Spain in which otters show diurnal activity and can be observed directly when foraging. We studied time of permanence in the water and fish catch rate during the period in which water levels were kept artificially low (autumn–winter 2015, 2016 and 2017). Results indicate that otters had at least two peaks of diurnal activity (from 10:00 to 11:00 a.m. far from sunrise and from 06:00 to 07:00 p.m. immediately before sunset). Otters spent an average of 74 min (54–94, 95% CI) in the water foraging daily, and had a minimum fish catch rate of ca 600 g h–1 of small fish. According to a pre-existing theoretical model, otters eating at that rate can satisfy their daily energy requirements with just 1.5 h of daily foraging activity, what roughly coincides with the upper confidence limit of the parameter estimate. When considering as well the capture of large fish otters obtained ca 850 g of fish per day in only 1.2 h in the water. Otters in the reservoir satisfy their daily requirements in autumn–winter with the same time investment than Shetland Island otters foraging during the day on marine fish during the summer. This coincidence is most likely due to the fact that winter water temperature in our study site is similar to that in the Shetland Islands in summer.

Urbanization and elevated cholesterol in American Crows

Abstract Although urban areas can be sources of abundant food for wildlife, anthropogenic foods may be lower in quality than natural food sources, with possible consequences for birds. We examined how urbanization and anthropogenic food were linked to cholesterol levels, condition, and survival of American Crows (Corvus brachyrhynchos). We collected cholesterol and landscape data from 140 crow nestlings along an urban-to-rural gradient in Davis, California, USA. We also ran a supplementation experiment with high-cholesterol fast food (McDonald’s cheeseburgers) on 86 nestlings in a rural population in Clinton, New York, USA. Plasma cholesterol increased with percentage of impervious surface along the urban-to-rural gradient. Cholesterol levels were sensitive to anthropogenic foods: crows supplemented with fast food cheeseburgers had higher cholesterol levels than unsupplemented crows. Elevated cholesterol levels had no detectable effects on survival and were associated with higher indices of body condition, although urbanization itself was linked to lower survival. Elevated cholesterol levels could indicate access to high-calorie, high-fat anthropogenic foods, which might, in some contexts, improve body condition, potentially offsetting other negative effects of urbanization. Observations over a longer time scale, assessing additional indices of health and fitness, are needed to evaluate long-term costs or benefits of elevated cholesterol for urban crows.

A Walk on the Wild Side: 2018 Cool-Season Forage Recommendations for Wildlife Food Plots in North Florida

Forage variety recommendation for wildlife. 
 Revised October 2019.
 Previous version: Blount, A., S. Olson, D. Francis, C. Mackowiak, H. Ober, J. Freeman, K. Quesenberry, R. Barnett, T. Wilson, and R. Gornto. 2013. “A Walk on the Wild Side: 2013 Cool-Season Forage Recommendations for Wildlife Food Plots in North Florida”. EDIS 2013 (11). https://journals.flvc.org/edis/article/view/88388.

Habitat selection by the European hare in arable landscapes: The importance of small-scale habitat structure for conservation.

Agricultural land‐use practices have intensified over the last decades, leading to population declines of various farmland species, including the European hare (Lepus europaeus). In many European countries, arable fields dominate agricultural landscapes. Compared to pastures, arable land is highly variable, resulting in a large spatial variation of food and cover for wildlife over the course of the year, which potentially affects habitat selection by hares. Here, we investigated within‐home‐range habitat selection by hares in arable areas in Denmark and Germany to identify habitat requirements for their conservation. We hypothesized that hare habitat selection would depend on local habitat structure, that is, vegetation height, but also on agricultural field size, vegetation type, and proximity to field edges. Active hares generally selected for short vegetation (1–25 cm) and avoided higher vegetation and bare ground, especially when fields were comparatively larger. Vegetation >50 cm potentially restricts hares from entering parts of their home range and does not provide good forage, the latter also being the case on bare ground. The vegetation type was important for habitat selection by inactive hares, with fabaceae, fallow, and maize being selected for, potentially providing both cover and forage. Our results indicate that patches of shorter vegetation could improve the forage quality and habitat accessibility for hares, especially in areas with large monocultures. Thus, policymakers should aim to increase areas with short vegetation throughout the year. Further, permanent set‐asides, like fallow and wildflower areas, would provide year‐round cover for inactive hares. Finally, the reduction in field sizes would increase the density of field margins, and farming different crop types within small areas could improve the habitat for hares and other farmland species.

Lethal Toxicity and Sublethal Metabolic Interference Effects of Sulfoxaflor on the Earthworm ( Eisenia fetida).

Testing for effects of pesticides on nontarget organisms is an integral part of ecological risk assessment. In the present study, the acute toxicity of sulfoxaflor to earthworms was evaluated using an artificial soil toxicity test, and sublethal effects were assessed through oxidative stress and metabolomics. Sulfoxaflor is a supertoxic pollutant to earthworms that easily bioaccumulates in earthworms, and contains LC2, LC10, and LC50 values of 0.08 (0.04-0.13), 0.19 (0.11-0.25), and 0.54 (0.45-0.65) mg/kg, respectively. Sublethal doses of sulfoxaflor resulted in oxidative damage to earthworms in which antioxidant enzymatic activities including SOD, CAT, and GST were significantly inhibited and MDA content accumulated. Metabolomics analysis suggested that the energy metabolism and the urea cycle in earthworms were significantly activated, while nucleotide metabolism was depressed, which could cause DNA damage. The results suggest earthworms have the potential to be a new entry point for sulfoxaflor into the wildlife food chain. Since earthworms significantly contribute to soil function and ecosystems, the high safety risks of sulfoxaflor to the earthworm could extend to the environment. In view of these findings, more attention should be given to the risks sulfoxaflor poses to the environment through its effects on earthworms.

Forest Fire Severity Affects Host Plant Quality and Insect Herbivore Damage

Abstract Climate change models predict increased forest fire occurrence and severity in the near future. Forest fire disturbance affects multiple ecological interactions, but there is little evidence for how naturally-occurring fires affect plant quality and herbivore damage, which is important because plants and herbivorous insects comprise most of the diversity in natural ecosystems and are responsible for a variety of ecosystem services. We surveyed three fires in the Rocky Mountains to investigate the effects of fire severity on wax currant (Ribes cereum), an important source of food and cover for wildlife in Colorado. We measured plant quality and herbivore damage; we found that fire severity had a significant negative effect on both measures. Notably, high severity fires decreased herbivore damage by about 50%. Furthermore, we found that the effect of fire on insect herbivore damage is mostly direct, but that indirect effects mediated through changes in plant quality are also significant. Our results have important implications for the effects of climate-driven increases in fire severity on plant-insect interactions, illustrating strong direct and weaker indirect negative effects of fire severity in a forest ecosystem.

The proposed algorithm for identifying agricultural problem areas for the needs of their reasonable management under land consolidation works

The development of agriculture in the territory of Poland and its production capacity is considerably differentiated in terms of space. At present, the country under discussion has agricultural areas which in many respects can compete with agriculture in the member states of the European Union. However, in some areas agricultural production run by private farms owned by individuals is on the verge of or falls below the limit of profitability. Such areas are called agricultural problem areas. These areas are increasingly exposed to marginalization and they are referred to as areas without a potential for development. Agriculture in such areas is doomed to failure. Therefore, it justifies promoting the alternative economic functions of problem areas in a rural setting. Such solutions include: allocating land for forest planting, building development, transport infrastructure, agritourism, and leisure, transformation into ecological areas, growing energy crops, wildlife food plots or gardening.Land consolidation is a process improving the spatial structure of rural areas, including problem areas. This geodesic operation makes it possible to describe the specific characteristics of selected agricultural problem areas and propose the most effective alternative methods of managing the described area. Thanks to rural management works, rural areas become competitive and cultivation of crops in such areas generates financial benefits and improves the living standard of their inhabitants.The universal algorithm for identifying problem areas, designed in this paper, can be a useful tool for programming land consolidation works because the results will make it possible to indicate options for the optimum management of such land. This paper takes into account criteria referring to a detailed description of the above-mentioned areas. Its advantage is that it can be used in different regions, no matter where the land consolidation object is located.

Groundwater Pollution Threats in the Republic of Macedonia due to Uncontrolled Landfills

AbstractWaste management practices are among the most important environmental issues in the Republic of Macedonia. Reusing, recycling, recovery and treatment of municipal solid waste are very limited. Nearly all municipal solid wastes in the country are disposed on landfills, out of which some are sanitary, while most are uncontrolled landfills/dumps and do not comply with the Directive 99/31/EC of 26 April 1999 set by the European Commission. This is a major environmental concern due to pollution of surrounding soil, ground and surface waters, human and wildlife food sources, animal habitat patterns and aesthetic impacts in the countryside. Available data about uncontrolled landfills locations are mapped and compared to the geology, hydrogeology, groundwater vulnerability as well as rainfall maps, upon which appropriate analysis is performed related to the groundwater contamination potential. The uncontrolled landfill sites and surrounding regions are then ranked according to their threats for groundwater contamination and prioritized for sustainable remediation.

Effects of Mowing and Tebuthiuron on the Nutritional Quality of Wyoming Big Sagebrush

Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) is the most abundant and widely distributed subspecies of big sagebrush and has been treated through chemical application, mechanical treatments, and prescribed burning in efforts thought to improve habitat conditions for species such as greater sage-grouse (Centrocercus urophasianus) and mule deer (Odocoileus hemionus). Although the response of structural attributes of sagebrush communities to treatments is well understood, there is a need to identify how treatments influence the quality of sagebrush as winter food for wildlife. Our purpose was to identify how mowing and tebuthiuron treatments influenced dietary quality of Wyoming big sagebrush in central Wyoming. Two study areas were mowed in January and February 2014, and tebuthiuron was applied in two study areas in May 2014. We constructed 6 exclosures in each of these four study areas (24 total), which encompassed 30 × 30 m areas of treated and untreated sagebrush within each exclosure. Samples of current annual growth were collected from 18 sagebrush plants from treated and 12 plants from control portions of mowing exclosures during November 2013–2015 and tebuthiuron exclosures during November 2014–2015. Samples were analyzed for crude protein and plant secondary metabolites known to influence dietary selection of sagebrush by sage-grouse and other sagebrush-occurring herbivores. Our results suggest mowing and tebuthiuron treatments may slightly increase crude protein concentrations directly after treatments without immediate changes in plant secondary metabolites. Slight increases in dietary quality of sagebrush following treatments coupled with potential trade-offs with loss of biomass associated with treatments corroborates previous research that treating Wyoming big sagebrush may have little benefit for sage-grouse and other sagebrush-dependent wildlife. Future work should evaluate not only how treatments influence sage-grouse habitat use and reproductive success but also how treatments influence other wildlife species in fragile sagebrush ecosystems.

Diversidad de macroinvertebrados fitófilos en arroyos de cabecera en pastizales de altura en Córdoba, Argentina

Macrophytes play an important role in lotic systems increasing habitat heterogeneity and providing food and shelter for wildlife. The aim of the study was to analyze the structure and composition of the invertebrate community associated with macrophytes in headwater streams in mountain grasslands (Ctalamochita sub-basin, Córdoba, Argentina) in two hydrological periods. The structure of the invertebrate assemblages in different macrophyte species (Hydrocotyle spp., Rorippa nasturtium-aquaticum and Ranunculus flagelliformis) was also evaluated. Three streams were sampled during high water (March 2012) and low water (August 2012) period. In each period, samples of invertebrates associated with the dominant macrophyte in each stream were collected. Seventy-two taxa of phytophilous macroinvertebrates were identified. The most frequent and abundant taxa were Naidinae, Hyalella curvispina, Americabaetis spp., Corynoneura spp. and Rheotanytarsus spp. Assemblages composition differed between hydrological periods and greater abundance of invertebrates was detected in R. nasturtium-aquaticum. The results showed that macrophyte patches in grassland headwater streams harbor an abundant and diverse invertebrate fauna and provide important base information for biomonitoring.

A Spanner in the Works: Human–Elephant Conflict Complicates the Food–Water–Energy Nexus in Drylands of Africa

The two major conservation issues for drylands of Africa are habitat loss or degradation and habitat fragmentation, largely from agriculture, charcoal production, and infrastructural development. A key question for management is how these landscapes can retain their critical ecological functions and services, while simultaneously supporting resilient livelihoods. It is a clear nexus question involving food (agriculture), water and energy (fuelwood), which is complicated by human-wildlife conflicts. While these could appear disparate issues, they are closely connected in dryland forest landscapes of Africa where elephants occur close to areas of human habitation. For instance, crop failure, whether due to weather or wildlife damage, is a key driver for rural farmers seeking alternative livelihoods and incomes, one of the commonest being charcoal production. Similarly, heavy reliance on wood-based energy often leads to degradation of wildlife habitat, which heightens competition with wildlife for food and water, increasing the possibility of crop-raiding. So, for multifunctional landscapes where elephants occur in close proximity with humans, any food-water-energy nexus activities towards achieving sustainability and resilience should consider human-elephant conflicts. Here, we broach these food-water-energy nexus issues with a focus on dryland areas of Africa and human-elephant conflicts. We highlight an ongoing study attempting to address this nexus holistically by employing a climate-smart agriculture and agro-forestry based design, augmented by an elephant deterrent study and an eco-charcoal production venture.

Who Should Read This Journal?

Human interactions with wildlife are a defining experience of human existence. These interactions can be positive or negative. People compete with wildlife for food and resources, and have eradicated dangerous species; co-opted and domesticated valuable ...Read More

Neglected effects of transport corridors: attractiveness to wildlife and role in conservation planning

Neglected effects of transport corridors: attractiveness to wildlife and role in conservation planning

Disentangling the effects of seminatural forestry on an ecosystem good: Bilberry (Vaccinium myrtillus) in Estonia

Abstract Management impacts on dominant and keystone species form a major sustainability issue in forests, because such impacts can affect production of ecosystem goods and trigger extinction cascades. On acidic soils in northern forests, bilberry ( Vaccinium myrtillus L.) is a well-known field-layer plant that is important culturally and as food for wildlife and humans, and is affected negatively by intensive forestry. In this paper, we analyse bilberry performance in a semi-natural forestry system (based on multiple native tree species and largely natural regeneration); specifically in relation to two major silvicultural activities—timber harvest and wetland drainage. We combined plot- and landscape-scale data from a range of forest types varying in soil moisture and nutrient richness in Estonia, and compiled a landscape retrospective of bilberry abundance. Clear-cutting sharply reduced bilberry abundance on mineral soils and green-tree retention only slightly mitigated that impact; however, in drier sites, some recovery had started in 10 years. By the mature stage of production forests (60–80 years post clear-cutting), bilberry cover had recovered to the levels observed in old growth. Artificial drainage increased bilberry cover on poor peat soils, and partial cutting of drained pine forests further enhanced it. A retrospective analysis of these patterns in a forest-wetland landscape revealed a net increase in bilberry cover and berry production during the past 70 years. We conclude that the studied forestry system has increased bilberry cover in boggy areas with likely benefits to some herbivores (e.g. grouse) at the expense of wetland species; however, negative effects of clear-cutting prevail in dry pine forests that are the preferred berry-picking sites for humans.

Biomonitoring of 2,4,6-trinitrotoluene and degradation products in the marine environment with transplanted blue mussels (M. edulis)

Since World War I considerable amounts of warfare material have been dumped at sea worldwide, but little is known about the fate of the explosive components in the marine environment. Sea dumped munitions are able to contaminate the surroundings because of the release of explosive chemicals due to corrosion and breaching or by detonation after blast-operations. This implies the risk of accumulation of toxic compounds in human and wildlife food chains. With the help of divers, we performed an active biomonitoring study with transplanted blue mussels (M. edulis) in a burdened area (Kolberger Heide, Germany) with explosive compounds near blast craters over an exposure time of 93days. With this biomonitoring system, we could show that blue mussels accumulate 2,4,6-trinitrotoluene (TNT) and its metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) in their tissues. In all mussels deployed at the ground, we found a body burden with 2-ADNT of 103.75±12.77ng/g wet weight and with 4-ADNT of 131.31±9.53ng/g wet weight. TNT itself has been found in six mussels with an average concentration of 31.04±3.26ng/g mussel wet weight. In the mussels positioned at one meter above the ground no TNT nor 2-ADNT could be detected, but 4-ADNT was found in all samples with an average concentration of 8.71±2.88ng/g mussel wet weight. To the best of our knowledge, this is the first study using blue mussels M. edulis as an active biomonitoring system for TNT and its metabolites 2-ADNT and 4-ADNT in a free field experiment in a burdened area. Moreover, with this system, we unequivocally proved that these toxic explosives accumulate in the marine biota resp. in the marine food chain, thereby posing a possible risk to the marine ecosphere and human health.

Changing Wild Meat Consumption: An Experiment in the Central Amazon, Brazil

AbstractMillions of people across the tropics rely on wildlife for food and income. However, overhunting to satisfy this demand is causing the decline of many species; an issue known as the wild meat crisis. We applied a before‐after control‐intervention design to assess the effects of social marketing (an information campaign and community engagement) with and without an economic incentive (discount coupons for chicken) on wild meat consumption. Coupons increased chicken consumption, as expected, but did not reduce wild meat consumption. In contrast, social marketing without the price incentive reduced wild meat consumption by ∼62%. This study demonstrates how social marketing and price incentives may be effective at reducing demand for meat and other wildlife products.

Selective bioaccumulation of neonicotinoids and sub-lethal effects in the earthworm Eisenia andrei exposed to environmental concentrations in an artificial soil

In this study, we evaluated the bioaccumulation of neonicotinoid insecticides in the earthworm Eisenia andrei exposed to environmental concentrations (<200 ng g−1 dry weight, nominal concentration) in an artificial soil. We tested the selectivity for neonicotinoids by exposing earthworms to 7 neonicotinoids alone and in more complex mixtures of 54 pesticides then 69 organic contaminants (OCs) (54 pesticides and 15 pharmaceuticals). We applied long-term (56-day) toxicity tests to further evaluate the effect of OCs on earthworms. We monitored adult survival, adult DNA damage using a comet assay on earthworm coelomocyte cells, and reproduction performance (i.e. number of cocoons and number and dry weight of juveniles). A selective bioaccumulation of neonicotinoid insecticides in adult and juvenile earthworms was found. This bioaccumulation is concomitant with a significant increase in adult DNA damage and significant effects on reproduction when earthworms were exposed to neonicotinoid insecticides alone. This study reveals a new potential point of entry of neonicotinoid insecticides into the wildlife food chain and also shows that E. andrei reproduction could be affected by long-term exposure to environmental concentrations of OCs.

Predictive framework for estimating exposure of birds to pharmaceuticals.

We present and evaluate a framework for estimating concentrations of pharmaceuticals over time in wildlife feeding at wastewater treatment plants (WWTPs). The framework is composed of a series of predictive steps involving the estimation of pharmaceutical concentration in wastewater, accumulation into wildlife food items, and uptake by wildlife with subsequent distribution into, and elimination from, tissues. Because many pharmacokinetic parameters for wildlife are unavailable for the majority of drugs in use, a read-across approach was employed using either rodent or human data on absorption, distribution, metabolism, and excretion. Comparison of the different steps in the framework against experimental data for the scenario where birds are feeding on a WWTP contaminated with fluoxetine showed that estimated concentrations in wastewater treatment works were lower than measured concentrations; concentrations in food could be reasonably estimated if experimental bioaccumulation data are available; and read-across from rodent data worked better than human to bird read-across. The framework provides adequate predictions of plasma concentrations and of elimination behavior in birds but yields poor predictions of distribution in tissues. The approach holds promise, but it is important that we improve our understanding of the physiological similarities and differences between wild birds and domesticated laboratory mammals used in pharmaceutical efficacy/safety trials, so that the wealth of data available can be applied more effectively in ecological risk assessments. Environ Toxicol Chem 2017;36:2335-2344. © 2017 SETAC.

Abundance of Insect Fauna Associated withAmaranthus hypochondriacusL. Crop, in Relation to Natural Living Fences

Abstract. Abundance of insect fauna associated with Amaranthus hypochondriacus L. in small-holder farm conditions, in terms of field complexity was studied. Agroecology theory suggests that natural fence rows reinforce good microclimatic conditions in a crop field, and provide food and cover for wildlife that could benefit the crop. However, organisms respond differently to the presence of an edge which could be positive or negative, and the response is driven by the form of the edge. In total, 1,621 specimens were collected in the insect orders Coleoptera, Diptera, Hymenoptera, Lepidoptera, Neuroptera, Orthoptera, the suborders Heteroptera, Homoptera, superfamily Mantodea, family Aleyrodidae, and class Arachnida. Results revealed that even when abundance of Heteroptera and Homoptera differ between sample areas of living fences, no fences, and natural vegetation, overall abundance was not related with field complexity. Response of arthropods to the presence of a natural living fence was neutral. However, ...

Importance of depth in soil to corm survival inErythronium americanum(Liliaceae)

Abstract Erythronium americanum (Trout Lily) is a common spring ephemeral in northeast forests. It is important to nutrient retention in the spring, serves as food for wildlife and has aesthetic value with its early visibility and attractive flower. Corms of E. americanum survive the winter and summer in a dormant state, and the plants expend energy using droppers to send corms deeper at the end of their active period in the spring. I investigated the importance of depth in soil to corm survival by planting ten corms at 1, 5 and 10 cm depth for both the summer of 2014 and the winter of 2014–2015 in a hardwood forest in southeastern New York State. In the winter, a second treatment was added in which snow was removed after each storm for the first and last four weeks of snow cover. During the summer, corms at 5 and 10 cm depth had a significantly greater chance of survival to fall than those at 1 cm. During the winter, corm survival to spring was higher at 10 cm depth than at 1 or 5 cm depth in the control...