Description of a new species of Mesochaetopterus (Annelida, Polychaeta, Chaetopteridae), with redescription of Mesochaetopterus xerecus and an approach to the phylogeny of the family

Mesochaetopterus rogeri sp. nov. , a new large chaetopterid polychaete from the Mediterranean Sea, is described. The analyses of partial sequences from the nuclear 18S rRNA (643 bp) and the mitochondrial cytochrome oxidase I (577 bp) genes of representative individuals of all known chaetopterid genera indicated the initial assignment of the new species into Mesochaetopterus . These analyses also supported the monophyly of the family and revealed two well-supported clades: Chaetopterus/Mesochaetopterus and Spiochaetopterus/Phyllochaetopterus . Mesochaetopterus rogeri sp. nov. is close to Mesochaetopterus xerecus , which is redescribed here from newly collected material. Mesochaetopterus rogeri sp. nov. was characterized as follows: (1) two long tentacles with dorsal transversal black bands of alternating widths (sometimes with two additional longitudinal light-brown bands); (2) region A with nine chaetigers (up to 12), with 13–19 modified chaetae in the fourth chaetiger; (3) region B with three flat segments, with accessory feeding organs in the second and third segments; (4) sandy straight tubes, 2.5-m long or more, vertically embedded in the sand. In the Bay of Blanes, M. rogeri sp. nov. occurs between 6- and 9-m deep (but also up to 30-m deep), in a patchy distribution (< 1 individual m⁻²), with maximum densities in April/June (likely to be the result of recruitment events), and minimum densities in September/November (likely to be a behavioural response to increasing sediment dynamics). Although it was originally thought that M. rogeri sp. nov. could be an introduced species, we argue that it is probably a native of the Mediterranean that has been overlooked by scientists up to now.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 201–225.     

When dispersal fails: unexpected genetic separation in Gibraltar macaques (Macaca sylvanus)

Barbary macaques (Macaca sylvanus), now restricted in the wild to a few isolated forested areas of Morocco and Algeria, are present in a free‐ranging colony on Gibraltar. For many decades, the Gibraltar colony was exposed to multiple bottlenecks due to highly nonrandom removal of animals, followed by repeated introductions of animals from North Africa. Moreover, because of complete isolation, Gibraltar's several social groups of macaques provide an ideal system to study the genetic consequences of dispersal in cercopithecines in situ. Predictions of genetic consequences due to male‐biased dispersal in cercopithecines will be different for autosomal and maternally inherited genetic markers, such as the control region of the mitochondrial DNA. We used a panel of 14 highly polymorphic microsatellite loci and part of the hypervariable region I of the mitochondrial control region to estimate genetic structure between five social groups in Gibraltar. Surprisingly, for autosomal markers, both classical summary statistics and an individual‐based method using a Bayesian framework detected significant genetic structure between social groups in Gibraltar, despite much closer proximity than wild Algerian and Moroccan populations. Mitochondrial data support this finding, as a very substantial portion of the total genetic variation (70.2%) was found between social groups. Using two Bayesian approaches, we likewise identified not only a small number of male first‐generation immigrants (albeit less than expected for cercopithecines) but also unexpectedly a few females. We hypothesize that the culling of males that are more likely to disperse might slow down genetic homogenization among neighbouring groups, but may also and more perversely produce selection on certain behavioural traits. This may have important repercussions for conservation, as it could lead to evolutionary changes that are not due to inbreeding or genetic drift.     

Systematics of Vitaceae from the viewpoint of plastid rbcL DNA sequence data

A phylogenetic analysis of plastid rbcL DNA sequences for 20 species of Vitaceae s.l. (including Leeaceae) and eight outgroups from Dilleniaceae and Santalales is presented. Patterns of floral and vegetative morphology and ontogeny within the family are compared to the phylogenetic trees produced. Despite the limited sampling of large and variable genera, there is a good correspondence with hypothesized floral and vegetative ontogenetic trends, with Leea and Ampelopsis ancestral, Cissus and Ampelocissus intermediate and Vitis most derived. A clade containing Parthenocissus , Tetrastigma , Cyphostemma and Vitis is found in all shortest trees. Cyphostemma and Parthenocissus are shown to be closely related to Vitis , to which clade Tetrastigma and Cayratia comprise the sister clade. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 421–432.     

Rubisco Activity: Effects of Drought Stress

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activityis modulated in vivo either by reaction with CO₂ and Mg²⁺ tocarbamylate a lysine residue in the catalytic site, or by thebinding of inhibitors within the catalytic site. Binding ofinhibitors blocks either activity or the carbamylation of thelysine residue that is essential for activity. At night, inmany species, 2-carboxyarabinitol-1-phosphate (CA1P) is formedwhich binds tightly to Rubisco, inhibiting catalytic activity.Recent work has shown that tight-binding inhibitors can alsodecrease Rubisco activity in the light and contribute to theregulation of Rubisco activity. Here we determine the influencethat such inhibitors of Rubisco exert on catalytic activityduring drought stress. In tobacco plants, ‘total Rubiscoactivity’, i.e. the activity following pre-incubationwith CO₂ and Mg²⁺, was positively correlated with leaf relativewater content. However, ‘total Rubisco activity’in extracts from leaves with low water potential increased markedlywhen tightly bound inhibitors were removed, thus increasingthe number of catalytic sites available. This suggests thatin tobacco the decrease of Rubisco activity under drought stressis not primarily the result of changes in activation by CO₂and Mg²⁺ but due rather to the presence of tight-binding inhibitors.The amounts of inhibitor present in leaves of droughted tobaccobased on the decrease in Rubisco activity per mg soluble proteinwere usually much greater than the amounts of the known inhibitors(CA1P and ‘daytime inhibitor’) that can be recoveredin acid extracts. Alternative explanations for the differencebetween maximal and total activities are discussed.     

Species richness estimation of bird communities: how to control for sampling effort?

Since estimates of total species richness increase with sampling effort, methods to control for this sampling effect need to be tested and used. We present seven non-parametric and 12 accumulation curve methods that have been used recently in the ecological literature. To test their performance, we used data from bird communities in the Queen Charlotte Islands, Canada. The performance of each method was evaluated by calculating the bias and precision of its estimates against the known total species richness. For our data set, the two Chao estimators were the overall least biased and most precise estimation methods, followed by the two jackknife estimators, thus supporting results of previous studies. Nonparametric estimators tended to perform better than accumulation curve models. Most estimation methods had the problem that they tended to underestimate species richness for early samples, but slightly overestimated it for late samples. We briefly discuss the practical use of these methods which may greatly increase our ability to answer ecological questions and to guide conservation decisions, especially for species-rich tropical bird communities.     

The potential of seed‐eating birds to spread viable seeds of weeds and other undesirable plants

The potential for seed‐eating birds to spread viable seeds was investigated using captive‐feeding trials to determine seed preference, passage time through the gut, and viability of passed seeds for bronzewing pigeons (Phaps chalcoptera), peaceful doves (Geopelia striata), crested pigeons (Ocyphaps lophotes), Senegal doves (Streptopelia senegalensis), zebra finches (Taeniopygia guttata), black ducks (Anas superciliosa) and wood ducks (Chenonetta jubata). Test seeds were bladder clover (Trifolium spumosum), crimson clover (Trifolium incarnatum), gorse (Ulex europaeus), canola (Brassica napus) and red panicum (Setaria italica). Their consumption was compared with that of commercial seed mixes. Although all test seeds were recognizable foods, their consumption usually decreased in the presence of other foods, except for canola, where consumption rates were maintained. Hard‐seeded bladder clover was the only species where viable seeds were passed by obligate seedeaters. In contrast, viable seeds of canola and gorse were passed by seed‐eating omnivorous/herbivorous ducks, although the germination of passed seeds (42%) was reduced significantly compared with that of untreated control seed (67%). Field validation with wild, urban bronzewings and Australian magpies (Gymnorhina tibicen) offered canola and commercial seed yielded similar outcomes, with a range of viable seeds recovered from magpie soft pellets. Mean seed passage time in captive birds ranged from 0.5 to 4.3 h for all test seeds and commercial seed mixes, suggesting that these bird species may potentially disperse seed over moderate distances. Despite the low probability of individual birds spreading viable seed, the high number of birds feeding in the wild suggests that the potential for granivorous and seed‐eating omnivorous birds to disperse viable seeds cannot be discounted, particularly if exozoochorous dispersal is also considered.