A damped precipitation‐driven,bottom‐up model for deer mouse population abundance in the northwestern United States

Small‐mammal population densities can be regulated by bottom‐up (food availability) and top‐down (predation) forces. In 1993, an El Niño Southern Oscillation event was followed by a cluster of human hantavirus with pulmonary syndrome in the southwestern United States. An upward trophic cascade hypothesis was proposed as an explanation for the outbreak: Increased plant productivity as a consequence of El Niño precipitations led to an unusual increase in distribution and abundance of deer mice (Peromyscus maniculatus ; reservoir host of Sin Nombre virus). Could such drastic events occur in mesic habitats, where plant productivity in response to climate conditions is likely to be much less dramatic? In this work, we investigate to what extent deer mouse populations follow a precipitation‐driven, bottom‐up model in central and western Montana and discuss important conditions for such a model to be possible. We found positive correlations between deer mouse abundance and on‐the‐ground measured plant productivity with a several‐month lag in three of six study sites. This effect was weaker when deer mouse populations were more abundant, indicating density‐dependent effects. Dispersal resulting from territoriality may be important in attenuating local density increments in spite of high food availability. In addition, there is evidence that population abundance in the study area could respond to other abiotic factors. In particular, precipitation in the form of snow may reduce deer mice survival, thus compensating the benefits of improved plant productivity. Deer mouse populations in Montana study sites follow complex dynamics determined by multiple limiting factors, leading to a damped precipitation‐driven bottom‐up regulation. This prevents dramatic changes in rodent abundances after sudden increments of food availability, such as those observed in other regions.     

Food and feeding habits of Clarias mossambicus from four areas in the Lake Victoria basin,East Africa

Synopsis The food and feeding habits of Clarias mossambicus in four habitat types in the northern Lake Victoria basin were studied. The importance of certain food types to this species varies from area to area. In the lake, rivers and swamps, C. mossambicus fed mainly on fish, particularly Haplochromis species. In the sewage ponds, Crustacea and insects were the main food items. The extent of ingestion by C. mossambicus of a given food type presumably reflects the availability and abundance of the food in the habitat. This constitutes a shift in the food habits which is of vital importance in this migratory fish. By employing several feeding methods, i.e. hunting, bottom feeding, surface feeding and filter feeding, C. mossambicus exploits a broad spectrum of food resources in the various habitats.Many modern workers consider Clarias mossambicus conspecific with C. gariepinus and a junior synonym of the latter (Editor)     

Contrasting Effects of Climate Change on Alpine Chamois

Global climate change can affect animal ecology in numerous ways, but researchers usually emphasize undesirable consequences. Temperature increases, for instance, can induce direct physiological costs and indirect effects via mismatches in resource needs and availability. Species living in mountainous regions, however, could experience beneficial effects because winters might become less severe. We examined the potentially opposing effects of climate change during spring, summer, and winter on recruitment in Alpine chamois (Rupicapra rupicapra). We examined initial recruitment (i.e., the ratio of kids to adult females) and net recruitment (i.e., the ratio of yearlings to adult females) of Alpine chamois through the use of linear mixed effects models and data from block count censuses performed across a 1,500-km² study area in the Italian Alps during summer from 2001 to 2015. Initial recruitment was relatively resistant to the effects of climate change, declining slightly over the study period. We suggest that the effects of increased forage availability and lower snow cover in winter may benefit the reproductive output of adult females, compensating for any negative effects of trophic mismatch and higher temperatures during summer. By contrast, net recruitment strongly declined throughout the study period, consistent with the slight decline of initial recruitment and the negative effects of increasing summer temperatures on the survival of kids during their first winter. These negative effects seemed to outweigh positive effects of climate change, even in a species strongly challenged by winter conditions. These findings provide important information for hunted populations; setting more appropriate hunting bags for yearling chamois should be considered. The ecological plasticity of the chamois, which also inhabits low altitudes, may allow a possible evolutionary escape for the species. © 2020 The Wildlife Society.     

Inferring the Demographic History of African Farmers and Pygmy Hunter–Gatherers Using a Multilocus Resequencing Data Set

The transition from hunting and gathering to farming involved a major cultural innovation that has spread rapidly over most of the globe in the last ten millennia. In sub-Saharan Africa, hunter–gatherers have begun to shift toward an agriculture-based lifestyle over the last 5,000 years. Only a few populations still base their mode of subsistence on hunting and gathering. The Pygmies are considered to be the largest group of mobile hunter–gatherers of Africa. They dwell in equatorial rainforests and are characterized by their short mean stature. However, little is known about the chronology of the demographic events—size changes, population splits, and gene flow—ultimately giving rise to contemporary Pygmy (Western and Eastern) groups and neighboring agricultural populations. We studied the branching history of Pygmy hunter–gatherers and agricultural populations from Africa and estimated separation times and gene flow between these populations. We resequenced 24 independent noncoding regions across the genome, corresponding to a total of ~33 kb per individual, in 236 samples from seven Pygmy and five agricultural populations dispersed over the African continent. We used simulation-based inference to identify the historical model best fitting our data. The model identified included the early divergence of the ancestors of Pygmy hunter–gatherers and farming populations ~60,000 years ago, followed by a split of the Pygmies' ancestors into the Western and Eastern Pygmy groups ~20,000 years ago. Our findings increase knowledge of the history of the peopling of the African continent in a region lacking archaeological data. An appreciation of the demographic and adaptive history of African populations with different modes of subsistence should improve our understanding of the influence of human lifestyles on genome diversity.     

Migration patterns of pronghorn in southwestern North Dakota

Wildlife managers need empirical data about pronghorn (Antilocapra americana) movements in North Dakota to assess whether mid-summer surveys represent occupancy of pronghorn in hunting units during the fall hunting season. Using data from 121 radiocollared pronghorn we evaluated patterns of pronghorn migrations in southwestern North Dakota from 2004 to 2007. Pronghorn exhibited 2 primary movement patterns between summer and winter ranges: migrations >15 km (45%) and movement <15 km (55%). Most migratory pronghorn moved northeast or east in the spring and southwest or west in the fall. Average distance moved for migratory pronghorn was 70.6 km (range = 17.4–253 km). Mean date of pronghorn migration in spring was 20 March (SD = 20 days) and in fall was 22 October (SD = 17 days). Nearly all migratory pronghorn (97%) returned to within 15 km of their previous summer range, whereas only 61% of pronghorn returned to within 15 km of their previous winter range. Most pronghorn moved across hunting and survey unit boundaries; however, only 7 fall migrations occurred between the aerial survey and the hunting season. During years of our study, the mid-summer survey provided representative information about hunting unit occupancy of radiocollared pronghorn for the fall hunting season. © 2011 The Wildlife Society     

Small trees,big problems: Comparative leaf function under extreme edaphic stress

Premise of the Study

The pygmy forest, a plant community of severely stunted conifers and ericaceous angiosperms, occurs on patches of highly acidic, nutrient‐poor soils along the coast of Northern California, USA. This system is an excellent opportunity to study the effect of severe nutrient deficiency on leaf physiology in a naturally‐occurring ecosystem. In this study, we seek to understand the physiological mechanisms stunting the plants' growth and their implications for whole plant function.

Methods

We measured 14 traits pertaining to leaf photosynthetic function or physical structure on seven species. Samples were taken from the pygmy forest community and from conspecifics growing on higher‐nutrient soils, where trees may grow over 30 m tall.

Key Results

Pygmy plants of most species maintained similar area‐based photosynthetic and stomatal conductance rates to conspecific controls, but had lower specific leaf area (leaf area divided by dry weight), lower percent nitrogen, and less leaf area relative to xylem growth. Sequoia sempervirens, a species rare in the pygmy forest, had a categorically different response from the more common plants and had remarkably low photosynthetic rates.

Conclusions

Pygmy plants were not stunted by low photosynthetic rates on a leaf‐area basis; instead, several species had restricted whole‐plant photosynthesis due to low leaf area production. Pygmy plants of all species showed signs of greater carbon investment in their leaves and higher production of nonphotosynthetic leaf tissue, further contributing to slow growth rates.     

The Economic Importance of Communal Net Hunting Among the BaAka of the Central African Republic

This article examines current net hunting practice by BaAka Pygmies of central Africa. In terms of time allocation, net hunting remains the single most important activity for the BaAka, But net hunting is only one in a range of subsistence and economic activities among which individuals switch on a daily basis. Returns from net hunting are roughly equivalent to those from competing activities. Several factors encourage the decline of net hunting and its replacement with snare hunting: enforcement of park regulations, higher individual returns to snare hunting, and greater involvement in formal employment and agriculture. However, net hunting has not been abandoned completely for several reasons: the local market demand for bushmeat is growing, numerous forest products besides meat are collected on net hunts, and economic alternatives remain irregular and unreliable.     

Public Access for Pheasant Hunters: Understanding an Emerging Need

Ring-necked pheasant (Phasianus colchicus; i.e., pheasant) hunting participation is declining across North America, reflecting a larger downward trend in American hunting participation and threatening benefits to grassland conservation and rural economies. To stabilize and expand the pheasant hunting population, we must first identify factors that influence pheasant hunter participation. We used an extensive in-person hunter survey to test the hypothesis that hunter demographics interact with social-ecological traits of hunting locations to affect hunter decisions, outcomes, and perceptions. We built a series of Bayesian mixed effects models to parse variation in demographics, perceptions, and hunt outcomes of pheasant hunters interviewed at public access hunting sites across 3 regions in Nebraska, USA, that varied in pheasant abundance and proximity to urban population centers. Among pheasant hunters in Nebraska, access to private lands was negatively related to the human population density of a pheasant hunter's home ZIP code and the distance a hunter had traveled to reach a hunting location. Pheasant hunters interviewed closer to metropolitan areas tended to be more urban and travel shorter distances, and their parties were more likely to include youth but less likely to include dogs. Hunter satisfaction was positively associated with seeing and harvesting pheasants and hunting with youth. Whereas youth participation and the number of pheasants seen varied by study region, hunter satisfaction did not differ across regions, suggesting that hunters may calibrate their expectations and build their parties based on where they plan to hunt. The variation in hunter demographics across hunting locations and disconnects between social and ecological correlates of hunter satisfaction suggests that diverse pheasant hunting constituencies will be best served by diverse pheasant hunting opportunities. © 2019 The Wildlife Society.     

Aerial hunting behaviour and predation success by peregrine falcons Falco peregrinus on starling flocks Sturnus vulgaris

Predators use diverse hunting strategies to maximize hunting success, while preys adopt anti‐predator strategies to maximize escape chances, among which flocking, communal roosting, and the related collective responses are a common pattern in gregarious species. Prey‐predator interactions involving a single predator and flocks, a common situation in birds, have received little attention. We studied predation behaviour and success of peregrine falcons Falco peregrinus on starlings Sturnus vulgaris, a highly gregarious species, in proximity of two winter roosts. A total of 328 hunting sequences, with an overall success of 23.1% were recorded. They usually consisted of several attacks, predation success being higher when hunting sequences lasted less than 1.5 min, included less than 3 attacks and no other falcons were hunting simultaneously. Predation success was higher when hunts were directed on singletons than on flocks. However, most hunting sequences were directed towards flocks. Nine hunting strategies on flocks were identified. The most frequent was the ‘surprise attack’, which was also the most successful. We suggest that this strategy minimizes the amount of anti‐predator display elicited by flocks and economizes energy spent in hunting. The constant predation pressure did not seem to affect the use of roosts by starlings, consistent with the ‘dilution’ hypothesis, while falcons captured at least one prey item every evening. Communal roosting may benefit predator and prey, as both sides could have reached a mutual local equilibrium.     

Subsistence productivity and hunting effort in native South America

The question of why people work more or less at various activities is an old one in anthropology and recently has surfaced in studies of native South American societies. Growing out of debates about protein scarcity, arguments have arisen over the reasons why people spend time on hunting and fishing. Some authors suggest that labor allocation and other societal features can be explained with reference to absolute minimum requirements for specific nutrients (e.g., protein). This study presents data from four native Central Brazilian societies on the time spent at various subsistence tasks and the productivity of those tasks. The evidence suggests that decisions to allocate labor to hunting and fishing are influenced more by the overall possibilities for production in an area than by the availability of animal proteins alone. Satisfaction of calorie requirements appears to take precedence over satisfaction of protein requirements. In those societies in which gardening is highly productive, people can spend more time on hunting and fishing and improve the overall quality of their diet.     

Climate change and perishable food hoards of an avian predator: Is the freezer still working?

Changing climate can modify predator–prey interactions and induce declines or local extinctions of species due to reductions in food availability. Species hoarding perishable food for overwinter survival, like predators, are predicted to be particularly susceptible to increasing temperatures. We analysed the influence of autumn and winter weather, and abundance of main prey (voles), on the food‐hoarding behaviour of a generalist predator, the Eurasian pygmy owl (Glaucidium passerinum), across 16 years in Finland. Fewer freeze–thaw events in early autumn delayed the initiation of food hoarding. Pygmy owls consumed more hoarded food with more frequent freeze–thaw events and deeper snow cover in autumn and in winter, and lower precipitation in winter. In autumn, the rotting of food hoards increased with precipitation. Hoards already present in early autumn were much more likely to rot than the ones initiated in late autumn. Rotten food hoards were used more in years of low food abundance than in years of high food abundance. Having rotten food hoards in autumn resulted in a lower future recapture probability of female owls. These results indicate that pygmy owls might be partly able to adapt to climate change by delaying food hoarding, but changes in the snow cover, precipitation and frequency of freeze–thaw events might impair their foraging and ultimately decrease local overwinter survival. Long‐term trends and future predictions, therefore, suggest that impacts of climate change on wintering food‐hoarding species could be substantial, because their ‘freezers’ may no longer work properly. Altered usability and poorer quality of hoarded food may further modify the foraging needs of food‐hoarding predators and thus their overall predation pressure on prey species. This raises concerns about the impacts of climate change on boreal food webs, in which ecological interactions have evolved under cold winter conditions.     

Dietary shifts,niche relationships and reproductive output of coexisting Kestrels and Long-eared Owls

Summary Food samples of breeding Kestrels (Falco tinnunculus) and Long-eared Owls (Asio otus) were collected in the peak and low phase of their preferred prey (Microtus voles) in western Finland. Diets of pairs that bred as neighbours (1 km) with interspecifics were compared with those of non-neighbours. In both species, neighbouring pairs fed less on Microtus voles and more on alternative prey than did non-neighbours. Competition theory predicts that diet overlap should be lower during prey shortage and that diet similarity should be especially reduced in neighbouring pairs. Observations were consistent with expectations: diet similarity was lower in the low vole years and neighbouring pairs showed less diet overlap that non-neighbours. Differences in habitat composition and prey availability at the sample sites should not confuse the results. In addition to the high diet similarity, hunting habitats and nest sites of the species overlapped almost completely; they only showed clear temporal segregation in hunting. Probably because of food competition, the neighbouring pairs of both species produced significantly fewer young than the non-neighbours. These results contrast with the view that the diet composition and dietary shift of rodent-feeding predatory birds can be interpreted in terms of simple opportunistic foraging. In the breeding season, interspecific competition for food seems to be an important factor that affects the niches of these species, especially in northern areas, where the seasonal low phase of voles in spring and the number of alternative prey are lower than in more southern areas.     

Spring snow goose hunting influences body composition of waterfowl staging in Nebraska

A spring hunt was instituted in North America to reduce abundance of snow geese (Chen caerulescens) by increasing mortality of adults directly, yet disturbance from hunting activities can indirectly influence body condition and ultimately, reproductive success. We estimated effects of hunting disturbance by comparing body composition of snow geese and non-target species, greater white-fronted geese (Anser albifrons) and northern pintails (Anas acuta) collected in portions of south-central Nebraska that were open (eastern Rainwater Basin, ERB) and closed (western Rainwater Basin, WRB; and central Platte River Valley, CPRV) to snow goose hunting during springs 1998 and 1999. Lipid content of 170 snow geese was 25% (57 g) less in areas open to hunting compared to areas closed during hunting season but similar in all areas after hunting was concluded in the ERB. Protein content of snow geese was 3% (14 g) less in the region open to hunting. Greater white-fronted geese had 24% (76 g; n = 129) less lipids in the hunted portion of the study area during hunting season, and this difference persisted after conclusion of hunting season. We found little difference in lipid or protein content of northern pintails in relation to spring hunting. Indirect effects of spring hunting may be considered a collateral benefit regarding efforts to reduce overabundant snow goose populations. Disrupted nutrient storage observed in greater white-fronted geese represents an unintended consequence of spring hunting that has potential to adversely affect reproduction for this and other species of waterbirds staging in the region. © 2012 The Wildlife Society.     

Trophy hunting and perceived risk in closed ecosystems: Flight behaviour of three gregarious African ungulates in a semi‐arid tropical savanna

Although being an important conservation tool in Africa, trophy hunting is known to influence risk perception in wildlife species, thus affecting the behaviour and fitness of most targeted species. We studied the effects of trophy hunting on the flight behaviour of impala (Aepyceros melampus), greater kudu (Tragelaphus strepsiceros) and sable (Hippotragus niger) in two closed ecosystems, Cawston Ranch (hunting area) and Stanley and Livingstone Private Game Reserve (tourist area), western Zimbabwe. Using standardized field procedures, we assessed the flight behavioural responses of the three species in two seasons: non‐hunting (December–March) and hunting (April–November) between March 2013 and November 2014. We tested the effect of habitat, group size, sex, season, start distance and alert distance on flight initiation distance using linear mixed models. Habitat, group size sex and alert distance did not have any effect on flight initiation distance for the three species. The three species were more alert and displayed longer flight initiation distances in the hunting area compared with the tourist area. Flight initiation distances for the three species were higher during the hunting season for the hunting area and low during the non‐hunting season. Flight distances of the three species did not differ between the hunting area and the tourist area. We concluded that trophy hunting increased perceived risk of wild ungulates in closed hunting areas, whereas ungulates in non‐hunting areas are less responsive and somehow habituated to human presence. Management plans should include minimum approach distances by tourists as well as establishing seasonal restrictions on special zones to promote species viability. Research aimed at integrating behavioural responses with physiological aspects of target species should be promoted to ensure that managers are able to deal with the behavioural trade‐offs of trophy hunting at local and regional scale.     

Ka'apor ritual hunting

Several investigators cite population control, frequent settlement relocation, trekking, expansion of diet breadth, and food taboos as strategic responses to game depletion by indigenous populations living in interfluvial zones of lowland South America. The Ka'apor Indians of the interfluvial forest of northern Maranhão, Brazil, employ other means of optimizing hunting efficiency, partly based on ritual. Menstruating women, pubescent girls, and parents of newborns can consume meat only of the tortoise (Gochelone denticulata), the first prey species to be hunted out of an area. Tortoise capture requires, on average, one full day of hunting. This means that the full potential of hunting pressure does not materialize near the settlement. Meat productivity is unusually high even near old settlements. I argue that ritual tortoise hunting helps to regulate environmental utilization, to maintain a sustained yield of meat protein, and to expand the catchment area gradually.     

Large Mammal Distribution in a Transfrontier Landscape: Trade‐offs Between Resource Availability and Human Disturbance

Understanding factors that affect the persistence of charismatic megafauna in human‐dominated landscapes is crucial to inform conservation decision‐making and reduce human‐wildlife conflict. We assessed the effect of environmental and anthropogenic factors at different landscape and management scales in predicting the distribution of African elephant (Loxodonta africana) within the Greater Mapungubwe Transfrontier Conservation Area in Southern Africa. We combined aerial distribution counts over a 12‐yr period with 14 variables, representing food availability, landscape, and anthropogenic effects, into generalized linear models. Generalized linear models were run for the broader landscape, as well as three separate management units within the broader landscape, namely ecotourism, trophy hunting, and a combination of hunting and ecotourism. Human activities within different management units forced elephant to trade‐off between disturbance avoidance, and good food and water availability. In addition, the important predictors of elephant distribution within each of the management units differed from the predictors at the broader landscape. Overall, our results suggest that at the fine scale, elephant are constraint by factors that may be masked at the broader landscape scale. We suggest that accounting for anthropogenic disturbance is important in determining the distribution of large, wide‐ranging, mammal species in increasingly human‐dominated landscapes, and that modeling needs to be done at the spatial scales at which conservation decisions are made.     

Relationship Between Small-game Hunting and Carnivore Diversity in Central Spain

Small-game hunting plays an important economic role in central Spain and some game species are key food resources for threatened predators. Small carnivores may reduce numbers of important game species. To alleviate predation pressure on game populations, management is often focused on predator control. Control methods can be non-selective, and so could potentially have a negative impact on non-target carnivore species, affecting carnivore guild composition and diversity. Using data on carnivore diversity in 70 quadrants (5 × 5 km) in a large area of central Spain with two main land uses (small-game hunting and a mixture of big-game hunting and forestry), we assessed how game management was related to carnivore diversity. Carnivore species richness was significantly lower in those areas managed for small-game hunting than in areas where other land uses predominated. The apparently least affected species by predator control was the red fox (Vulpes vulpes), the main target species of predator control. Results suggested that low carnivore species richness was linked to small-game hunting activities, which was probably associated with non-selective predator control practices. Therefore, in order to reconcile carnivore conservation and economic goals it is imperative to develop and to evaluate selective predator control techniques.     

Contrasting phenotypic correlations in food provision of male Tengmalm's owls (Aegolius funereus) in a temporally heterogenous environment

Summary We examined the food provision rate of male Tengmalm's owls,Aegolius funereus, during one 3 year vole cycle consisting of consecutive low, increase and peake vole years. The data were collected in the midnestling period when males provisioned the whole family. In the low vole year, males with a low loading index (g/cm²) of flying area fed their offspring more often than did males with a high loading index, whereas in the peak vole year the opposite trend was evident. Similar relationships were found in the food mass provisioned to the nest. In the increase vole year, male body size had no effect on feeding efficiency. In the peak vole year, when large voles are abundant, heavy males preyed on larger voles than were generally available in their territories, indicating that largeness may increase strike power in hunting attempts. In the low vole year, when breeding is costly due to food scarcity and extensive hunting area, small males are more economical fliers and efficient hunters than large males. The contrasting trends in correlations between male size and feeding efficiency in years of vole abundance versus scarcity suggest that no fixed phenotype may most efficiently cope with variable food supply.     

Badger <Emphasis Type="Italic">Meles meles</Emphasis> feeding ecology in dry Mediterranean environments of the southwest edge of its distribution range

The dietary preference of badgers Meles meles (Linnaeus, 1758) for earthworms and other food resources has been widely discussed. In the Mediterranean area, rabbits Oryctolagus cuniculus, fruits (mainly olives Olea europaea) and arthropods are the most important foods. We describe badger dietary habits in a xeric Mediterranean area, comparing use and availability of olives and rabbits. Our results indicated that olives and rabbits are the predominant resources consumed, however we did not detect any evidence of specialisation when we compared consumption versus field availability. In the case of olives we found that their consumption is reduced when juvenile rabbits or figs Ficus carica are widely available, which is evidence against any specialisation in this resource. Figs appear to be a key food item for badgers; they were consumed in large amounts when available. Badgers in this xeric area can be viewed as generalist or facultative specialists, using the most profitable resource when available but shifting its preferences to other less profitable food resources when availability of other primary food resource are reduced. Our results also indicated the high suitability of some human agricultural uses (eg fruit orchards) for this species, especially in the otherwise harsh Mediterranean environments.     

Sex effect on habitat selection in response to hunting disturbance: the study of wild boar

Spatial variation of the ‘predation risk’ due to human activities or distribution may increase the sexual difference in habitat selection. Indeed, females with offspring are usually more risk adverse than males. Based on a long-term wild boar study, we analysed the diurnal distribution of female and male wild boar before, during and after the hunting period. Hunting, food and foliation were investigated as factors affecting patterns of forest parcel selection. As expected, dense vegetative covers were selected during resting periods, but wild boar decreased this pattern of habitat selection in response to hunting disturbance. Moreover, the habitat selection of wild boar did not fit with the variation of food availability (presence or absence of mast) and the vegetation cycle. As expected, sows responded more to the hunting disturbance than males, leading to a more pronounced sexual difference during the riskier season. The unexpected decrease of bush use may be explained either by the increased hunting effort in this habitat or by the increased movements between resting sites due to disturbance, leading to a more random habitat selection pattern. The observed difference between sexes could result from a higher response of females with offspring to hunting, leading to an increased frequentation of secondary habitats, whereas males can tolerate more risks and remain hidden in thicket plots. Our results highlight how hunting disturbance can lead game species to change their patterns of refuge habitat selection and may affect the habitat segregation between the sexes.