Chromosome studies of 8 species of parrots of the families Cacatuidae and Psittacidae (Aves: Psittaciformes)

The karyotypes of 7 species of Psittaciformes new to cytology are described: Cacatua galerita, Calyptorhynchus magnificus and Probosciger aterrimus of the Cacatuidae, and Ara macao, A. ararauna, Amazona viridigenalis and Psittrichas fulgidens of the Psittacidae. For reasons of comparison the karyotype of Melopsittacus undulatus is also described. These karyotypes are compared to 8 psittaciform karyotypes previously recorded. There is a remarkable heterogeneity of karyotypes in the Psittaciformes. Nevertheless, it seems possible to recognize Cacatua, Calyptorhynchus and probably also Probosciger (Cacatuidae) by their karyotypes as a clearly related group. The karyotypes of these cacatuids also bear some resemblance to that of Loriculus (Psittacidae). The psittacid genera Amazona, Ara, Nestor, Melopsittacus, Psittacula, Psittacus and Psittrichas are karyologically heterogeneous, but their karyotypes show certain relationships. The karyotype of Brotogeris is very different from those of other psittacids.     

Biological invasions and scientific objectivity: Reply to Cassey et al. (2005)

Abstract We disagree with the assertion that recent human‐caused invasions differ substantially from historic natural invasions in their magnitudes and impacts on ecological processes. The position that exotic species are inherently ‘bad’ and should be eradicated is an ethical judgement, usually based on the naturalist fallacy or xenophobic prejudice; it is not a scientific judgement. The role of scientists in studying invasive species should be to gather, interpret and communicate information as accurately and objectively as possible.     

Determinants of vertebrate invasion success in Europe and North America

Species that are frequently introduced to an exotic range have a high potential of becoming invasive. Besides propagule pressure, however, no other generally strong determinant of invasion success is known. Although evidence has accumulated that human affiliates (domesticates, pets, human commensals) also have high invasion success, existing studies do not distinguish whether this success can be completely explained by or is partly independent of propagule pressure. Here, we analyze both factors independently, propagule pressure and human affiliation. We also consider a third factor directly related to humans, hunting, and 17 traits on each species' population size and extent, diet, body size, and life history. Our dataset includes all 2362 freshwater fish, mammals, and birds native to Europe or North America. In contrast to most previous studies, we look at the complete invasion process consisting of (1) introduction, (2) establishment, and (3) spread. In this way, we not only consider which of the introduced species became invasive but also which species were introduced. Of the 20 factors tested, propagule pressure and human affiliation were the two strongest determinants of invasion success across all taxa and steps. This was true for multivariate analyses that account for intercorrelations among variables as well as univariate analyses, suggesting that human affiliation influenced invasion success independently of propagule pressure. Some factors affected the different steps of the invasion process antagonistically. For example, game species were much more likely to be introduced to an exotic continent than nonhunted species but tended to be less likely to establish themselves and spread. Such antagonistic effects show the importance of considering the complete invasion process.     

The comparative importance of species traits and introduction characteristics in tropical plant invasions

Aim We used alien plant species introduced to a botanic garden to investigate the relative importance of species traits (leaf traits, dispersal syndrome) and introduction characteristics (propagule pressure, residence time and distance to forest) in explaining establishment success in surrounding tropical forest. We also used invasion scores from a weed risk assessment protocol as an independent measure of invasion risk and assessed differences in variables between high‐ and low‐risk species. Location East Usambara mountains, Tanzania. Methods Forest transect surveys identified species establishing in disturbed and intact forest. Leaf traits (specific leaf area and foliar nutrient concentrations) were measured from leaves sampled in high‐light environments. Results A leaf traits spectrum was apparent, but species succeeding or failing to establish in either disturbed or intact forest were not located in different parts of the spectrum. Species with high invasion risk did not differ in their location on the leaf trait spectrum compared with low‐risk species but were more likely to be bird/primate‐dispersed. For 15 species establishing in forest quadrats, median canopy cover of quadrats where seedlings were present was correlated with a species value along the leaf trait spectrum. Species establishing in disturbed forest were planted in twice as many plantations and were marginally more likely to be bird‐ or primate‐dispersed than species failing to become established in disturbed forest. Establishment in intact forest was more likely for species planted closer to forest edges. Main conclusions Leaf and dispersal traits appear less important in the colonization of tropical forest than introduction characteristics. It appears, given sufficient propagule pressure or proximity to forest, alien species are much more likely to establish independently of leaf traits or dispersal syndrome in continental tropical forests.     

A new species of the feather mite genus Titanolichus Gaud & Atyeo, 1996 (Acari: Astigmata: Pterolichidae) from the endangered orange-bellied parrot Neophema chrysogaster (Aves: Psittaciformes) from Australia

Abstract  Titanolichus seemani sp. n., a new species of the genus Titanolichus Gaud & Atyeo, 1996, is described from a museum skin of the endangered orange-bellied parrot Neophema chrysogaster (Latham) (Aves: Psittaciformes) from Australia. We also redescribe the type species Titanolichus chiragricus (Mégnin & Trouessart) from the ground parrot Pezoporus wallicus (Kerr), provide a key for all known species of Titanolichus and point out some problems in the systematics of this genus.     

The parrots (Aves: Psittaciformes) from the Middle Miocene of Sansan (Gers,Southern France)

The occurrence of Archaeopsittacus sp. (Psittaciformes) in the fossil deposits of Sansan (France) is reported, testifying to a survival of this genus in the Middle Miocene, as Archaeopsittacus verreauxi was described from the Early Miocene of Saint-Gérand-le-Puy (France) and was recorded only from its type locality. The data discussed here indicate the presence of two parrot species from Sansan, as it is the type locality of another parrot species, Pararallus dispar, only known from this locality. The differences between the humeri of these two taxa are described in detail, together with the differences from the other European fossil parrot species. The presence of more than one species of parrot in the same locality is not rare, but in Europe it is recorded in Sansan for the second time. Evidence for parrots also confirms the paleoenvironmental reconstruction of Sansan, as parrots are primarily arboreal species. Archaeopsittacus also represents one of the few common elements between the Early and Middle Miocene European bird assemblages.     

The evolution of the Indian Ocean parrots (Psittaciformes): extinction, adaptive radiation and eustacy

Parrots are among the most recognisable and widely distributed of all bird groups occupying major parts of the tropics. The evolution of the genera that are found in and around the Indian Ocean region is particularly interesting as they show a high degree of heterogeneity in distribution and levels of speciation. Here we present a molecular phylogenetic analysis of Indian Ocean parrots, identifying the possible geological and geographical factors that influenced their evolution. We hypothesise that the Indian Ocean islands acted as stepping stones in the radiation of the Old-World parrots, and that sea-level changes may have been an important determinant of current distributions and differences in speciation. A multi-locus phylogeny showing the evolutionary relationships among genera highlights the interesting position of the monotypic Psittrichas, which shares a common ancestor with the geographically distant Coracopsis. An extensive species-level molecular phylogeny indicates a complex pattern of radiation including evidence for colonisation of Africa, Asia and the Indian Ocean islands from Australasia via multiple routes, and of island populations ‘seeding’ continents. Moreover, comparison of estimated divergence dates and sea-level changes points to the latter as a factor in parrot speciation. This is the first study to include the extinct parrot taxa, Mascarinus mascarinus and Psittacula wardi which, respectively, appear closely related to Coracopsis nigra and Psittacula eupatria.     

New feather mites of the family Pterolichidae (Acari: Pterolichoidea) from parrots (Aves: Psittaciformes) in Australia

Abstract Seven new feather mite species of the family Pterolichidae are described from various Australian parrots: Apexolichus lathami sp. n. from the swift parrot, Lathamus discolor (Shaw); Titanolichus platycerci sp. n. and Rhytidelasma punctata sp. n. from the pale-headed rosella, Platycercus adscitus (Latham); R. striata sp. n. from the Australian king-parrot, Alisterus scapularis (Lichtenstein); Lorilichus stenolobus sp. n. and Lorilichus curvilobus sp. n. from the rainbow lorikeet, Trichoglossus haematodus (Linnaeus); Psittophagus galahi sp. n. from the galah, Eolophus roseicapillus (Vieillot). We give a brief overview of taxonomic studies of pterolichid mites living on Psittaciformes, and discuss the main diagnostic characters of different generic groups of these mites.     

Out of the Bassian province: historical biogeography of the Australasian platycercine parrots (Aves,Psittaciformes)

Schweizer, M., Güntert, M. & Hertwig, S. T. (2012). Out of the Bassian province: historical biogeography of the Australasian platycercine parrots (Aves, Psittaciformes). —Zoologica Scripta, 42, 13–27. Aridification from mid‐Miocene onwards led to a fragmentation of mesic biomes in Australia and an expansion of arid habitats. This influenced the diversification of terrestrial organisms, and the general direction of their radiations is supposed to have been from mesic into drier habitats. We tested this hypothesis in the platycercine parrots that occur in different habitats in Australia and also colonized Pacific islands. We inferred their temporal and spatial diversification patterns using a Bayesian relaxed molecular clock approach based on three nuclear and two mitochondrial genes and model‐based biogeographic reconstructions. The Bassian biota was found to be the centre of origin of platycercine parrots and diversification within two of their three clades coincided with the beginning of aridification of Australia. The associated habitat changes may have catalysed their radiation through adaptation to arid environments and vicariance because of the fragmentation of non‐arid habitats. The small oceanic islands of Melanesia contributed as stepping stones for the colonization of New Zealand from Australia.     

A multilocus molecular phylogeny of the parrots (Psittaciformes): support for a Gondwanan origin during the cretaceous

The question of when modern birds (Neornithes) first diversified has generated much debate among avian systematists. Fossil evidence generally supports a Tertiary diversification, whereas estimates based on molecular dating favor an earlier diversification in the Cretaceous period. In this study, we used an alternate approach, the inference of historical biogeographic patterns, to test the hypothesis that the initial radiation of the Order Psittaciformes (the parrots and cockatoos) originated on the Gondwana supercontinent during the Cretaceous. We utilized broad taxonomic sampling (representatives of 69 of the 82 extant genera and 8 outgroup taxa) and multilocus molecular character sampling (3,941 bp from mitochondrial DNA (mtDNA) genes cytochrome oxidase I and NADH dehydrogenase 2 and nuclear introns of rhodopsin intron 1, tropomyosin alpha-subunit intron 5, and transforming growth factor ss-2) to generate phylogenetic hypotheses for the Psittaciformes. Analyses of the combined character partitions using maximum parsimony, maximum likelihood, and Bayesian criteria produced well-resolved and topologically similar trees in which the New Zealand taxa Strigops and Nestor (Psittacidae) were sister to all other psittaciforms and the cockatoo clade (Cacatuidae) was sister to a clade containing all remaining parrots (Psittacidae). Within this large clade of Psittacidae, some traditionally recognized tribes and subfamilies were monophyletic (e.g., Arini, Psittacini, and Loriinae), whereas several others were polyphyletic (e.g., Cyclopsittacini, Platycercini, Psittaculini, and Psittacinae). Ancestral area reconstructions using our Bayesian phylogenetic hypothesis and current distributions of genera supported the hypothesis of an Australasian origin for the Psittaciformes. Separate analyses of the timing of parrot diversification constructed with both Bayesian relaxed-clock and penalized likelihood approaches showed better agreement between geologic and diversification events in the chronograms based on a Cretaceous dating of the basal split within parrots than the chronograms based on a Tertiary dating of this split, although these data are more equivocal. Taken together, our results support a Cretaceous origin of Psittaciformes in Gondwana after the separation of Africa and the India/Madagascar block with subsequent diversification through both vicariance and dispersal. These well-resolved molecular phylogenies will be of value for comparative studies of behavior, ecology, and life history in parrots.     

Phylogenetic relationships and historical biogeography of neotropical parrots (Psittaciformes: Psittacidae: Arini) inferred from mitochondrial and nuclear DNA sequences

Previous hypotheses of phylogenetic relationships among Neotropical parrots were based on limited taxon sampling and lacked support for most internal nodes. In this study we increased the number of taxa (29 species belonging to 25 of the 30 genera) and gene sequences (6388 base pairs of RAG-1, cyt b, NADH2, ATPase 6, ATPase 8, COIII, 12S rDNA, and 16S rDNA) to obtain a stronger molecular phylogenetic hypothesis for this group of birds. Analyses of the combined gene sequences using maximum likelihood and Bayesian methods resulted in a well-supported phylogeny and indicated that amazons and allies are a sister clade to macaws, conures, and relatives, and these two clades are in turn a sister group to parrotlets. Key morphological and behavioral characters used in previous classifications were mapped on the molecular tree and were phylogenetically uninformative. We estimated divergence times of taxa using the molecular tree and Bayesian and penalized likelihood methods that allow for rate variation in DNA substitutions among sites and taxa. Our estimates suggest that the Neotropical parrots shared a common ancestor with Australian parrots 59 Mya (million of years ago; 95% credibility interval (CrI) 66, 51 Mya), well before Australia separated from Antarctica and South America, implying that ancestral parrots were widespread in Gondwanaland. Thus, the divergence of Australian and Neotropical parrots could be attributed to vicariance. The three major clades of Neotropical parrots originated about 50 Mya (95% CrI 57, 41 Mya), coinciding with periods of higher sea level when both Antarctica and South America were fragmented with transcontinental seaways, and likely isolated the ancestors of modern Neotropical parrots in different regions in these continents. The correspondence between major paleoenvironmental changes in South America and the diversification of genera in the clade of amazons and allies between 46 and 16 Mya suggests they diversified exclusively in South America. Conversely, ancestors of parrotlets and of macaws, conures, and allies may have been isolated in Antarctica and/or the southern cone of South America, and only dispersed out of these southern regions when climate cooled and Antarctica became ice-encrusted about 35 Mya. The subsequent radiation of macaws and their allies in South America beginning about 28 Mya (95% CrI 22, 35 Mya) coincides with the uplift of the Andes and the subsequent formation of dry, open grassland habitats that would have facilitated ecological speciation via niche expansion from forested habitats.     

Comparative analysis of microsatellite variability in five macaw species (Psittaciformes, Psittacidae): Application for conservation

Cross-amplification was tested and variability in microsatellite primers (designed for Neotropical parrots) compared, in five macaw species, viz., three endangered blue macaws (Cyanopsitta spixii [extinct in the wild], Anodorhynchus leari [endangered] and Anodorhynchus hyacinthinus [vulnerable]), and two unthreatened red macaws (Ara chloropterus and Ara macao). Among the primers tested, 84.6% successfully amplified products in C. spixii, 83.3% in A. leari, 76.4% in A. hyacinthinus, 78.6% in A. chloropterus and 71.4% in A. macao. The mean expected heterozygosity estimated for each species, and based on loci analyzed in all the five, ranged from 0.33 (A. hyacinthinus) to 0.85 (A. macao). As expected, the results revealed lower levels of genetic variability in threatened macaw species than in unthreatened. The low combined probability of genetic identity and the moderate to high potential for paternity exclusion, indicate the utility of the microsatellite loci set selected for each macaw species in kinship and population studies, thus constituting an aid in planning in-situ and ex-situ conservation.     

沙地樟子松天然分布与引种栽培

樟子松以其抗寒、抗旱和较速生等优良特性成为我国北方干旱、半干旱风沙区防护林和用材林造林的主要树种 ,但自 2 0世纪 90年代以来 ,沙地樟子松人工林出现了不同程度的衰退现象 ;更为严重的是目前我国樟子松人工造林仍在北方干旱、半干旱地区大面积推广 ,因此 ,探明沙地樟子松人工林产生衰退的原因 ,并更好地经营管理该树种人工林 ,对我国北方防护林/人工林建设具有重大意义。本文在广泛收集国内外有关樟子松研究结果的基础上 ,详述了樟子松在我国的天然分布概况 ,对沙地樟子松在引种栽培方面 ,即沙地樟子松的种源区划、种子品质的比较、种子的遗传特性及适应性等研究进展进行了综述 ,提出了在沙地樟子松引种栽培研究中亟待解决的一些问题和建议 ,对今后该树种沙地人工林经营研究具有参考价值。     

Competition, predation and nest niche shifts among tropical cavity nesters: phylogeny and natural history evolution of parrots (Psittaciformes) and trogons (Trogoniformes)

Nest site selection by birds is a critically important life history trait as competition for suitable sites can be intense, and because birds are at their most vulnerable to predators during nesting. Previous studies show that the clutch size and nestling period evolve in response to competition for nest sites and nest predation, respectively. This provides the opportunity to study the relative contribution of competition and predation to the evolution of nesting niche. Using previously published phylogenies for parrots and trogons, I found evidence for at least 13 independent evolutionary transitions from tree cavities to alternative nesting niches (including termitaria, cliffs, and burrows). I analyzed variations in clutch size, incubation period and nestling period for 16 phylogenetically controlled pairs of species to test the relative roles of competition for tree cavities and nest predation, in favoring evolutionary switches to alternative nest sites. Tree cavity nesting species did not have larger clutch sizes as predicted if competition for tree cavities leads birds to invest heavily in nesting once they obtain a nest site (the limited breeding opportunities hypothesis). Instead I found that shifts to alternative nesting niches were accompanied by an increase in nestling period. As nestling period is a surrogate measure for long-term nest predation rates, this finding suggests that nest predation has been more important than competition in niche diversification among cavity nesting parrots and trogons. The timing of events in South America suggests that the explosive radiation of mammalian nest predators during the Upper-Oligocene, Lower-Miocene (20–30 million years ago) corresponded with the radiation of parrot and trogon taxa that exploit novel nesting niches.