Migration of a Peregrine Falcon Falco peregrinus calidus from Saudi Arabia to Cape Town as revealed by satellite telemetry

In boreal autumn 1995, we tracked a migrating adult Peregrine Falcon Falco peregrinus calidus from the border of Saudi Arabia and Yemen to near Cape Town, South Africa, a distance of 6 346?km. While on migration it covered 288?km d?1, on average. During its migration in Africa it migrated faster than any other Peregrine tracked so far using satellite telemetry. Falco p. calidus is an uncommon, but regular, migrant to southern Africa, where it overlaps with the resident F. p. minor, but no other bird has been tracked so far south.     

The role of chromatic and achromatic signals for fruit detection by birds

Fruit color changes during ripening are typically viewed asan adaptation to increase signal efficacy to seed dispersers.Plants can increase signal efficacy by enhancing chromatic (wavelengthrelated) and/or achromatic (intensity related) contrasts betweenfruit and background. To assess how these contrasts determinethe detectability of fruit signals, we conducted 2 experimentswith free-flying crows (Corvus ossifragus) under seminaturalconditions in a 2025 m² aviary. Crows searched first for artificialred and black fruits and detected red fruits from a larger distance.Because artificial red fruits had higher chromatic and lowerachromatic contrasts against foliage than artificial black fruits,crows apparently prioritized chromatic contrasts. Thus, thecommon change in fruit color from red to black during ripeningdoes not increase signal efficacy to crows. In a second trial,crows searched for UV-reflecting and black blueberries (Vaccinummyrtillus) against backgrounds of foliage and sand. Againstfoliage, UV-reflecting berries had higher chromatic and achromaticcontrasts than black berries, and crows detected them from alarger distance. Against sand, UV-reflecting berries had lowachromatic contrasts and black berries low chromatic contrasts.Crows detected both fruit types equally, suggesting that theyused chromatic contrasts to detect UV-reflecting berries andachromatic contrasts to detect black berries. Birds prioritizedchromatic contrasts when searching for artificial red fruitsin foliage but not when searching for blueberries on sand. Wesuggest that the relative importance of chromatic and achromaticcontrasts is contingent on the chromatic and achromatic varianceof the background. Models of signal perception can be improvedby incorporating background-specific effects.     

A population genetic analysis of migration: the case of the noctule bat (Nyctalus noctula)

Although rarely assessed, the population genetics of hibernating colonies can help to understand some aspects of population structure, even when samples from nursery or mating colonies are not available, or in studies of migration when both types of samples are available and can be compared. Here we illustrate both points in a survey of mitochondrial DNA (mtDNA) control region sequences used to study the population genetics of hibernating colonies of a migrating species, the noctule bat (Nyctalus noctula). Lacking samples from Scandinavian nursery colonies, we use a North European hibernacula to suggest that Scandinavian populations are isolated from Central and East European colonies. Then, we compare genetic diversities of nursery and hibernating colonies. We find a significantly higher haplotype diversity in hibernacula, confirming that they consist of individuals from different nursery colonies. Finally, we show that pairwise comparisons of the haplotype frequencies of nursery and hibernating colonies contain some information on the migration direction of the noctule bat.     

Comparative evolution of flower and fruit morphology

Angiosperm diversification has resulted in a vast array of plant morphologies. Only recently has it been appreciated that diversification might have proceeded quite differently for the two key diagnostic structures of this clade, flowers and fruits. These structures are hypothesized to have experienced different selective pressures via their interactions with animals in dispersal mutualisms, resulting in a greater amount of morphological diversification in animal-pollinated flowers than in animal-dispersed fruits. I tested this idea using size and colour traits for the flowers and fruits of 472 species occurring in three floras (St John, Hawaii and the Great Plains). Phylogenetically controlled analyses of nearest-neighbour distances in multidimensional trait space matched the predicted pattern: in each of the three floras, flowers were more divergent from one another than were fruits. In addition, the spacing of species clusters differed for flowers versus fruits in the flora of St John, with clusters in flower space more divergent than those in fruit space. The results are consistent with the idea that a major driver of angiosperm diversification has been stronger selection for divergent floral morphology than for divergent fruit morphology, although genetic, physiological and ecological constraints may also play a role.     

Changes in species interactions across a 2.5 km elevation gradient: effects on plant migration in response to climate change

Predicted climate change in the Andes will require plant species to migrate upslope to avoid extinction. Central to predictions of species responses to climate change is an understanding of species distributions along environmental gradients. Environmental gradients are frequently modelled as abiotic, but biotic interactions can play important roles in setting species distributions, abundances, and life history traits. Biotic interactions also have the potential to influence species responses to climate change, yet they remain mostly unquantified. An important interaction long studied in tropical forests is postdispersal seed predation which has been shown to affect the population dynamics, community structure, and diversity of plant species in time and space. This paper presents a comparative seed predation study of 24 species of tropical trees across a 2.5 km elevation gradient in the Peruvian Andes and quantifies seed predation variation across the elevational gradient. We then use demographic modelling to assess effects of the observed variation in seed predation on population growth rates in response to observed increasing temperatures in the area. We found marked variation among species in total seed predation depending on the major seed predator of the species and consistent changes in seed predation across the gradient. There was a significant increase in seed survival with increasing elevation, a trend that appears to be driven by regulation of seed predators via top–down forces in the lowlands giving way to bottom–up (productivity) regulation at mid‐ to high elevations, resulting in a ninefold increase in effective fecundity for trees at high elevations. This potential increase in seed crop size strongly affects modelled plant population growth and seed dispersal distances, increasing population migration potential in the face of climate change. These results also indicate that species interactions can have effects on par with climate in species responses to global change.     

Migration, wintering and breeding of a lesser spotted eagle ( Aquila pomarina) from Slovakia tracked by satellite

In northern Slovakia an adult male Lesser Spotted Eagle (Aquila pomarina) occupied the same nest site for 11 years running (1992–2002), where it was ringed and fitted with two satellite transmitters. In six of these years it successfully reared a young. In 1994 and 2000–2002 its behaviour during migration could be followed in detail by means of satellite telemetry. The eagle took the known route for this species to South Africa. In 2001, it spent 43% of the year at its breeding site, 33% in its winter quarters, the remaining 24% being spent on migration. In three cases the autumn migration took 40, 48 and 61 days respectively. In two cases the spring migration took 49 days. All five recorded autumn and spring migrations averaged a daily flight distance of 178 km. In spring the daily flight distance was in general slightly greater than in autumn. The longest was recorded from 30 March to 2 April 2001, between Uganda and the Red Sea, during which the bird covered a total of 1,650 km, averaging 412 km per day. In 2001, the spring migration from the wintering grounds was 2 weeks later than in 2002. The wintering grounds, where in 2 years the bird spent around 3.5 months, covering at least 1,666 and 2,269 km, respectively, comprised a large part of Zimbabwe together with the Kruger National Park in South Africa and neighbouring parts of Mozambique. The annual journeys flown, including movements around the wintering grounds, amounted in 2000-2001 to at least 20,396 km and in 2001-2002 to 19,041 km. Except during its crossing of the Sahara, the eagle must have taken food on nearly all its days of migration.     

A spatially interactive simulation of climate change, harvesting, wind, and tree species migration and projected changes to forest composition and biomass in northern Wisconsin, USA

In the coming century, forecast climate changes caused by increasing greenhouse gases may produce dramatic shifts in tree species distributions and the rates at which individual tree species sequester carbon or release carbon back to the atmosphere. The species composition and carbon storage capacity of northern Wisconsin (USA) forests are expected to change significantly as a result. Projected temperature changes are relatively large (up to a 5.8°C increase in mean annual temperature) and these forests encompass a broad ecotone that may be particularly sensitive to climate change. Our objective was to estimate the combined effects of climate change, common disturbances, and species migrations on regional forests using spatially interactive simulations. Multiple scenarios were simulated for 200 years to estimate aboveground live biomass and tree species composition. We used a spatially interactive forest landscape model (LANDIS‐II) that includes individual tree species, biomass accumulation and decomposition, windthrow, harvesting, and seed dispersal. We used data from two global circulation models, the Hadley Climate Centre (version 2) and the Canadian Climate Center (version 1) to generate transient growth and decomposition parameters for 23 species. The two climate change scenarios were compared with a control scenario of continuing current climate conditions. The results demonstrate how important spatially interactive processes will affect the aboveground live biomass and species composition of northern Wisconsin forests. Forest composition, including species richness, is strongly affected by harvesting, windthrow, and climate change, although five northern species (Abies balsamea, Betula papyrifera, Picea glauca, Pinus banksiana, P. resinosa) are lost in both climate scenarios regardless of disturbance scenario. Changes in aboveground live biomass over time are nonlinear and vary among ecoregions. Aboveground live biomass will be significantly reduced because of species dispersal and migration limitations. The expected shift towards southern oaks and hickory is delayed because of seed dispersal limitations.     

河南省绿盲蝽和中黑盲蝽春季迁移能力的铷标记研究

利用铷标记方法对河南省绿盲蝽Apolygus lucorum(Meyer-Dür)和中黑盲蝽Adelphocoris suturalis Jakovlev的春季迁移现象进行了研究。结果表明:在河南省2种棉盲蝽均有较强的迁移能力。绿盲蝽2 d内可迁移2 560m(试验最远回捕距离),中黑盲蝽6 d内可迁移5 120 m(试验最远回捕距离)。本文提供了春季绿盲蝽和中黑盲蝽由越冬场所向棉田转移的直接证据。     

The fossil bat assemblage of Sima del Elefante Lower Red Unit (Atapuerca,Spain): First results and contribution to the palaeoenvironmental approach to the site

The fossil bat assemblage from the Lower Red Unit of Sima del Elefante (TELRU) in Atapuerca (Burgos, Spain) has been exhaustively analysed for the first time. Bat fossil assemblages are of particular relevance to palaeoenvironmental approaches to sites. Here we integrate our new data on the chiropteran fauna with the data provided previously by other authors on the basis of the small-vertebrate assemblages and the palynology of the site. Our results are consistent with the earlier results in that they indicate a generally warmer climate than at present in the area and stable environmental conditions throughout the major part of the TELRU sequence. However, fossil bat assemblages sometimes lead to problems when they are used in landscape reconstruction. These problems are discussed here and should be taken into account in future works.     

The migration syndrome in the African armyworm moth, Spodoptera exempts: allocation of resources to flight and reproduction

Abstract. Selection for the capacity for prolonged tethered flight in Spodoptera exempta resulted in heavier moths, with significantly larger abdominal glyceride glycerol contents in females of two flight-selected strains (87% and 49% higher than in the comparable non-selected strain) and in males of one of them (80% higher). All flight-selected strains contained individuals of both sexes with very high abdominal glyceride levels. There was no significant relationship between abdominal total glyceride glycerol after flight and flight duration for non-selected moths, but an inverse linear relationship was evident in both sexes from a flight-selected strain. Oxygen consumption during tethered flights by flight-selected moths ranged from 28.2 to 56.6 ml O₂g^-1h^-1.
Using these and previous data, notional energy budgets were calculated to account for flight, reproduction and resting metabolism for non-selected and flight-selected S. exempta flown on the flight balances and provided thereafter with distilled water. The results confirm the trade-off between flight and reproduction reported by Gunn et al. (1989). A similar approach using data for two non-selected strains from the field in Kenya indicated genetic variation in migratory potential, reflected both in pre-reproductive period and resources available for flight. We conclude that elevated glyceride levels are a component of the migratory syndrome in S. exempta and that this is the major factor underlying the curvilinear relationship between flight duration and fecundity obtained by Gunn et al. (1989).     

Intraspecific variation in seed dispersal of a Neotropical tree and its relationship to fruit and tree traits

The distribution of wind‐dispersed seeds around a parent tree depends on diaspore and tree traits, as well as wind conditions and surrounding vegetation. This study of a neotropical canopy tree, Platypodium elegans, explored the extent to which parental variation in diaspore and tree traits explained (1) rate of diaspore descent in still air, (2) distributions of diaspores dispersed from a 40‐m tower in the forest, and (3) natural diaspore distributions around the parent tree. The geometric mean rate of descent in still air among 20 parents was highly correlated with geometric mean wing loading^1/2 (r = 0.84). However, diaspore traits and rate of descent predicted less variation in dispersal distance from the tower, although descent rate⁻¹ consistently correlated with dispersal distance. Measured seed shadows, particularly their distribution edges, differed significantly among six parents (DBH range 62–181 cm) and were best fit by six separate anisotropic dispersal kernels and surveyed fecundities. Measured rate of descent and tree traits, combined in a mechanistic seed dispersal model, did not significantly explain variation among parents in natural seed dispersal distances, perhaps due to the limited power to detect effects with only six trees. Seedling and sapling distributions were at a greater mean distance from the parents than seed distributions; saplings were heavily concentrated at far distances. Variation among parents in the distribution tails so critical for recruitment could not be explained by measured diaspore or tree traits with this sample size, and may be determined more by wind patterns and the timing of abscission in relation to wind conditions. Studies of wind dispersal need to devote greater field efforts at recording the “rare” dispersal events that contribute to far dispersal distances, following their consequences, and in understanding the mechanisms that generate them.