Populations at the warm edge of distribution are more genetically diverse, and at the same time are more susceptible to climate change. Between 1987–1996, we studied Tawny Owls in Israel, the species’ global southern edge of distribution and a country undergoing a rapid land cover transformation for over a century. To assess the potential impacts of land cover transformation, we modelled the species’ most suitable habitat and climate and analyzed how climate and habitat affected the nesting success and prey selection. Moreover, we monitored Tawny Owl juveniles’ survival and ontogeny from eggs to dietary independent young, to find out whether the Israeli population is a sink. While the species distribution model correctly predicted the Tawny Owl’s densest areas of occurrence, it failed to predict its occurrence in adjacent regions. The model also predicted that areas included in the species’ historical range remained suitable habitats. The number of fledglings increased with precipitation and in rural settings but was adversely affected by extreme temperatures. While voles dominated the diet in all habitats, the Tawny Owl’s diet is considerably more variable than other Israeli owls. Our results suggest that the Tawny Owl can adapt to rural-agricultural environments, but is susceptible to climate change.
The Endangered mountain gazelle Gazella gazella was once widespread throughout the Levant. Over the past 100 years its population fluctuated greatly as a result of various anthropogenic threats and disturbances. We review the dynamics of the mountain gazelle throughout this period in Israel, its last remaining stronghold, with c. 5,000 individuals. During the 20th century Israel's human population increased steadily at an annual rate of 2%; the population density is currently 430 persons per km(2) and is forecast to increase further. This presents an array of threats to the mountain gazelle, including habitat change, fragmentation and isolation by roads, railways and fences, poaching, road kills and predation by increasing populations of natural predators and feral dogs, sustained partly by anthropogenic food waste. These threats may act in synergy to amplify their effects. We present an overview of how these factors acted in the past and are currently threatening the survival of this species. We also review the policy and management actions, both implemented and still required, to ensure the persistence of the mountain gazelle. In addition, we analyse connectivity in the landscape, highlighting highly fragmented gazelle populations, and suggest potential interventions. The mountain gazelle exemplifies an ungulate with both great vulnerability to human pressures and a large breeding potential. As more regions, in Israel and elsewhere, are converted to human dominated landscapes, pressures on wildlife are increasing, and lessons from the mountain gazelle could prove valuable.
The Mediterranean coastal dune habitat of Israel is diminishing rapidly, mostly due to massive urbanization, changes in habitat characteristics caused by dune stabilization and the presence of Acacia saligna, an invasive species brought to Israel for the purpose of dune stabilization. In this study we document the effect of sand stabilization on the composition of small mammal communities in the Ashdod-Nizzanim sands, Israel. We analyzed differences in species diversity and abundance for species of rodents in four types of habitat: unstable (mobile) sand dune, semi-stabilized dune, inter-dune depression and a plot of the invasive Acacia saligna. Rodent communities were found to undergo gradual changes concurrently with the stabilization of the sands. The mobile dune was the only habitat in which the strict psammophiles Jaculus jaculus and Gerbillus pyramidum were captured in abundance. No species commensal with human were captured neither in the mobile nor in the semi-stabilized dunes. However, in the inter-dune depression there was quite a large representation of Mus musculus, a rodent commensal with humans. The Acacia saligna plot had the lowest number of captures and the lowest rodent biomass calculated, with Mus musculus composing nearly half of the captures. The results of this study demonstrate that stabilization of the sands in Ashdod-Nizzanim area is associated with the disappearance of psammophile rodents and the appearance of species commensal with humans. In order to preserve the habitat for psammophile rodents, measures should be taken to halt the spread of acacia and the continuing stabilization of the sands.
The kiore (Rattus exulans) was introduced by Polynesians to many Pacific islands (hence the name Polynesian rat) in the past 3000 years. In the Pacific region, this species is known to vary in size in relation to latitude, island size and number of competing rat species. In this study, we use recently estimated settlement dates of Pacific islands to re-assess the spatial and temporal factors that determine body size (represented by greatest length of the skull) and the length of the upper tooth row (UTR) of the kiore. The relationship between skull size and UTR and their predictors are shown to be complex due to several significant interactions. In any environment, an organism is faced by many factors, each of which may produce a selection pressure whose effect may combine and interact with other factors. The significant interactions we detected indicate shifting trends in the morphology of the kiore under different geographical (i.e. latitude and island size), climatic and other conditions. We suggest that only a comprehensive consideration of all the relevant parameters and their interactions will provide a realistic understanding of how body parameters of an organism are affected by its local environment and settlement history.
We studied the effect of the two environmental indices, the sub‐polar gyre (SPG), and winter and summer North Atlantic Oscillation (NAO), together with mean annual winter and summer temperatures and geographic location on mandible size and body mass of Arctic foxes in Iceland (6345 and 2732 specimens, respectively) during the year of their death. We predicted that when favorable conditions prevailed, large specimens would be selected for, and vice versa. Body size and body mass were significantly affected by the environmental parameters (i.e. SPG, NAO, ambient temperature and cloud cover) prevailing during the year of death. The effect of environmental conditions on body size was much stronger in the less productive region of eastern Iceland, apparently because in areas where food availability is meager, even a small difference in climate may tilt the balance from food sufficiency to food shortage. Western Iceland comprises only a quarter of the total surface area of the country, but its productive seashores are twice as long as those of all the rest of the country combined. It is interesting to note that the effect of the SPG, a marine phenomenon in the oceans surrounding Iceland, is reflected in the condition of the foxes more than the other climatic variables we used in this study, which are largely land‐related. Because Arctic foxes in Iceland feed largely on marine birds and invertebrates, the SPG seems to encompass more accurate information regarding the direct ocean forces that affect food availability to the foxes.
Greenland is one of the coldest areas on earth that are inhabited by animals. In this study, we sought to examine the effect of several environmental factors on skull size of Arctic hares (Lepus arcticus). We measured 263 skulls of Arctic hares, collected in Greenland between 1906 and 1971. We employed two full models: one that includes latitude, longitude, and seasonal surface temperature during collection year and a second that includes the two spatial axes and the North Atlantic Oscillation (NAO) index during collection year. We found complex relationships between the examined parameters and hare skull size, which resemble the trends reported by Post & Forchhammer (2002) between the NAO index and the population dynamics of caribou and musk oxen in Greenland. Our two models provided a similar picture of opposite trends in skull size across Greenland, as reflected by the two-or three-way interactions (between latitude, longitude, and temperature in the first model, and latitude, longitude, and NAO in the second model). This complex picture, in which during both summer and winter the pattern of change in skull size toward north-east Greenland is an inverse of that observed in its south-west, is illustrated in Figure 3. The first and second models explained c. 31% and c. 25%, respectively, of the variation in skull size in both winter and summer. We discuss several possible mechanisms that could affect skull size in such an opposite way across Greenland.
Studies in Passerines have found that migrating species recruit more new neurons into brain regions that process spatial information, compared with resident species. This was explained by the greater exposure of migrants to spatial information, indicating that this phenomenon enables enhanced navigational abilities. The aim of the current study was to test this hypothesis in another order-the Columbiformes - using two closely-related dove species-the migrant turtle-dove (Streptopelia turtur) and the resident laughing dove (S. senegalensis), during spring, summer, and autumn. Wild birds were caught, treated with BrdU, and sacrificed 5 weeks later. New neurons were recorded in the hyperpallium apicale, hippocampus and nidopallium caudolaterale regions. We found that in doves, unlike passerines, neuronal recruitment was lower in brains of the migratory species compared with the resident one. This might be due to the high sociality of doves, which forage and migrate in flocks, and therefore can rely on communal spatial knowledge that might enable a reduction in individual navigation efforts. This, in turn, might enable reduced levels of neuronal recruitment. Additionally, we found that unlike in passerines, seasonality does not affect neuronal recruitment in doves. This might be due to their non-territorial and explorative behavior, which exposes them to substantial spatial information all year round. Finally, we discuss the differences in neuronal recruitment between Columbiformes and Passeriformes and their possible evolutionary explanations. Our study emphasizes the need to further investigate this phenomenon in other avian orders and in additional species.
We updated the list of species for which conspecific brood parasitism (CBP) has been reported, and it contained 256 species. We used this list to examine the effects of four factors on the rate of CBP (defined as the percentage of species where CBP was observed in a family), namely, phylogeny, geographic distribution, mode of reproduction (i.e. altricial/precocial) and diversification rate (mean number of species per genus in a family). CBP is influenced by phylogeny, appears to have multiple origins and has evolved many times in various branches of the avian phylogeny tree. As already well known, it is much more prominent among precocial than altricial birds, in which in some families of the former, most species (around 60% among Anatidae) and in some small families, even all species engage in CBP. In contrast, among altricial birds the highest levels of CBP are much lower and are found in the Ploceidae (14.5% of species) and Turdidae (12.8%). Of the three other examined parameters, only the mode of reproduction was significantly related to the rate of CBP, but accounted for only similar to 2% of the variation. Diversification rate and geographic distribution area were not correlated with CBP. These results further confirm that CBP is influenced by phylogeny and mode of reproduction. Literature searches revealed that the rate of appearance of articles on CBP typically increased for several years, starting in the late 1970s and early 1980s, levelled off during the first decade of the twenty-first century and then declined. This would seem to represent a recent decline in interest in the CBP phenomenon.
New neuronal recruitment in an adult animal's brain is presumed to contribute to brain plasticity and increase the animal's ability to contend with new and changing environments. During long-distance migration, birds migrating greater distances are exposed to more diverse spatial information. Thus, we hypothesized that greater migration distance in birds would correlate with the recruitment of new neurons into the brain regions involved with migratory navigation. We tested this hypothesis on two Palearctic migrants - reed warblers (Acrocephalus scirpaceus) and turtle doves (Streptopelia turtur), caught in Israel while returning from Africa in spring and summer. Birds were injected with a neuronal birth marker and later inspected for new neurons in brain regions known to play a role in navigation - the hippocampus and nidopallium caudolateral. We calculated the migration distance of each individual by matching feather isotopic values (δ(2)H and δ(13)C) to winter base-maps of these isotopes in Africa. Our findings suggest a positive correlation between migration distance and new neuronal recruitment in two brain regions - the hippocampus in reed warblers and nidopallium caudolateral in turtle doves. This multidisciplinary approach provides new insights into the ability of the avian brain to adapt to different migration challenges.
We report that two species of mouse-tailed bats (Rhinopoma microphyllum and R. cystops) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures (Ta, 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O2 g−1 h−1 for R. microphyllum and R. cystops, respectively) and aroused from torpor when Ta fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.
Aim In this paper we explore global links between tree canopy height and species richness of amphibians, birds and mammals. We follow the ideas first laid out by MacArthur and MacArthur in 1961 who found that in the eastern USA higher tree canopies supported more bird species, which they attributed to an increase of available niches as forests grow taller. We test if their findings can be generalized over large regions and other taxa by employing novel methods and using current datasets. Location Global Methods We used the global distribution maps of the three above taxa to infer species richness. Our tree canopy height information was derived from remotely sensed LiDAR data. The analysis was conducted globally and within biogeographical realms. We modeled richness, using tree canopy height and other environmental correlates, with generalized additive models and geographically weighted regressions. Results Globally, tree canopy height proved to be of lesser importance in explaining species richness patterns compared to other environmental drivers. Within biogeographical realms, tree canopy height was found to be a more important predictor of diversity in the N eotropic and A ustralian realms. Regional patterns show that tree canopy height has an important effect on diversity of amphibians throughout the world and in several tropical regions across taxa. N et P rimary P roductivity ( NPP ) explains more of the variation in richness both globally and within most regions. Main Conclusions Overall, tree canopy height is not an important predictor of diversity. However we highlight its relative importance in particular locations and settings.
We develop a model to evaluate the profitability of controlling rodent damage by placing barn owl nesting boxes in agricultural areas. The model incorporates the spatial patterns of barn owl predation pressure on rodents, and the impact of this predation pressure on nesting choices and agricultural output. We apply the model to data collected in Israel and find the installation of nesting boxes profitable. While this finding indicates that economic policy instruments to enhance the adoption of this biological control method are redundant, it does support stricter regulations on rodent control using rodenticides.
In monogamous species, conspecific aggression is a primary tactic to deter intruders. Alternative reproductive strategies, such as extra-pair copulations or intra-specific brood parasitism that peak at the pre-egg laying period and are practised by intruders, pose a significant threat to the monogamous pair. Here, we addressed the question whether male and female Palestine Sunbirds (Nectarinia osea) demonstrate different aggression levels toward conspecific intruders during the pre-egg laying period. We further asked whether indirect measures of certainty of paternity affect male aggression toward such intruders. For that, we measured the aggression of both partners toward intruders while using stuffed birds. We conducted two experiments on a monogamous and territorial Palestine Sunbird population. In the first experiment, we exposed breeding pairs to a conspecific or a heterospecific intruder and measured their aggression toward it. During the second experiment, we exposed breeding pairs to an intruder, before and after temporarily removing the local male. The local male demonstrated higher aggression than the local female toward a male decoy. Toward a female decoy, the local male demonstrated lower aggression than the local female. Following their release, the removed males did not change their aggression toward the male decoy, but rather they decreased their aggression toward the female decoy. These results suggest that the indirect male’s certainty of paternity may be an important factor of the male’s interests when he faces a risk of potential intra-specific brood parasitism. Furthermore, these findings suggest that each gender is more sensitive to its similar intruder gender, and acts according to its interests in terms of its aggression toward the intruder.
Although 90 % of all bird species are monogamous, many species practice alternative reproductive strategies as extra-pair copulations, intra-specific brood parasitism, and quasi-parasitism. In territorial monogamous species, both partners hold and defend the territory from intruders. Often, the intruders are males and usually the local male banishes the intruders. Indeed, many studies focused on the response of the local male toward intruder males. However, the benefits and costs associated with the responses of the local male toward intruder females have been largely overlooked. Focusing mainly on alternative reproductive strategies, we developed a model to predict the aggression a monogamous male may demonstrate toward an intruder female during the pre-egg laying stage of his local female partner. This model demonstrates that the intensity of aggression that the local male shows toward an intruder female depends on the extra-pair copulations that his local female partner may perform. Further, the aggression also depends upon intra-specific brood parasitism and quasi-parasitism that might be carried out by the intruder female. Our approach suggests that when considering mating strategies, there is a need to assess how these three alternative reproductive strategies may affect the local male's aggression toward intruder females.
Evidence suggests a possible correlation between learning abilities of adults and new neuronal recruitment into their brains. The hypothesis is that this brain plasticity enables animals to adapt to environmental changes. We examined whether there are differences in neuronal recruitment between resident and migrant birds. We predicted that migrants, which are more exposed to spatial changes than residents, will recruit more new neurons. To test this, we compared neuronal recruitment in two closely related bird species - the migrant reed warbler (Acrocephalus scirpaceus), and the resident Clamorous warbler (A. Stentoreus) - during spring, summer, and autumn. Wild birds were caught, treated with BrdU and sacrificed five weeks later. New neurons were recorded in the Hippocampus and Nidopallium caudolateral. The results support our hypothesis, as more new neurons were found in the migrant species, in both brain regions and all seasons. We suggest that this phenomenon enables enhanced navigational abilities, which are required for the migratory lifestyle. However, in contrast to our hypothesis, in spring we found less new neurons in adults of both species, as compared to other seasons. We suggest that in spring, when birds settle in breeding territories, they require less spatial skills, and this might enable to reduce the cost of neuronal recruitment, as reflected by less new neurons in their brains. We also found age differences, with overall higher neuronal recruitment in juveniles. Finally, we advocate the importance of studying wild populations, for a better understanding of the adaptive significance of neuronal replacement in the vertebrate brain.
•Bird species diversity is positively related to shrubs species richness.•Richness of trees and shrubs, small lawns and tree cover invite most bird species.•Native birds prefer to forage on native trees, while alien birds – on alien trees.•Bird species diversity changes with migrating seasons.•Presence of people and dogs has a negative effect on birds’ presence.
Migratory passerines were mist-netted during the spring and autumn migrations at two localities in Israel: fin Fashkha, a desert oasis near the Dead Sea, and Elon, a maquis vegetation area in the western Galilee. In both localities, mean body mass of the blackcap (Sylvia atricapilla) was significantly heavier in autumn, and heavier in the Galilee than in the oasis. More blackcaps were netted in spring at both sites. The robin (Erithacus rubecula) had heavier body mass in spring, and its capture rate was higher in autumn. In autumn, the blackcap passes through Israel loaded with fat on its way south to its winter quarters in East Africa. In spring, it arrives in relatively poor body condition after crossing the Sahara. A higher capture rate during springtime could be explained by the poor condition of the birds. The robin winters in Israel, and birds captured in autumn have just completed their migration, and carry little fat reserves, while those caught in spring are loaded with fat for their northward migration. Mean wing length of the reed warbler (Acrocephalus scirpaceus) was significantly longer in spring than in autumn. This is consistent with the species completing its moult in winter quarters and arriving in Israel in spring with relatively fresh feathers. Species composition at each locality indicates that most migrant species examined prefer habitats similar to those used during the breeding season.
ABSTRACT Species richness in Israel was studied by correlating the number of species of mammals, birds, and reptiles in 30 × 30 km squares with several environmental factors. The most diverse areas in Israel (in terms of number of species) were transition zones between the Mediterranean, Irano-Turanian, and Saharo-Arabian regions. For mammals and birds, the factors best correlated with species richness were, in decreasing order: number of isohyets per square, mean annual precipitation, and number of plant communities. These factors are highly correlated with latitude, hence a very high correlation exists between latitude and species richness. For reptiles, species richness was significantly correlated with the number of soil types, followed by mean annual evaporation and mean August temperature. Most environmental factors examined were highly correlated among themselves, hence no definite conclusion as to the most important factor can be drawn. For terrestrial vertebrates within Israel, species richness d...