We produced DNA sequence data from two mitochondrial genes (cytochrome b and the NADH dehydrogenase subunit 2) to reconstruct the phylogenetic relationships among 121 species of the Anseriformes (waterfowls including ducks, geese, swans, the magpie goose and screamers). Phylogenetic analyses converged into a congruent topology and defined several well-supported clades. We calibrated a molecular clock and reconstructed ancestral biogeographical areas using Bayesian inference supporting an austral continental (Gondwanaland) origin of the waterfowls. Ducks, swans and geese might have diversified during the Miocene (23-5 Myr ago) reaching northern distributions in Holarctic and Afrotropical regions. The evolution of hybridization patterns in Anseriformes has been investigated using a cladistic analysis (morphology), which may underestimate or overestimate the phylogenetic divergence among species, or restricted only to ducks. Using a phylogenetic framework, genetic-based distances and a Bayesian time calibration, our data support the hypothesis based on immunological distances of slow rate of appearance of reproductive incompatibilities in waterfowls compared with other vertebrates and the view that these birds may be like frogs in having lost their interspecific hybridization potential more slowly than mammals.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

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BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Reed die-back affects breeding biology of the Great Crested Grebe (Podiceps cristatus) at Lake Diimmer (Lower Saxony, Germany)In the beginning of the 90s the breeding population of the Great Crested Grebe on the hypertrophic shallow Lake Dtimmer decreased from almost 400 pairs to about 40-120 pairs. We addressed the question of whether this decrease was due to changes in prey availability or to changes in nesting sites. Fishing catches by gillnet and electrical fishing gear throughout the breeding season indicated that prey availability was not a limiting factor. In particular, lake whitefish were found to occur in high densities. In the pre-laying period the whitefish stock consisted of individuals with 17.1 cm total length on average. In the following periods of hatching and rearing the young, the fish stock was dominated by juveniles of small size. Observations of breeding pairs and parents feeding their young support the hypothesis that prey availability was high: (1) We found no evidence that nowadays clutches are smaller than in the 80s. In 1998 clutch size did not decrease with laying date and first clutches were not significantly larger than second clutches. (2) In hunting for prey fishes for their chicks, adults grebes were very successful. The mode time interval between two feedings did not exceed 20 seconds. With regard to prey size we found no evidence for active or passive selection by the Grebes. Obvious changes in reproductive behaviour were related to the nesting sites. In the 80s most pairs nested in flooded reed beds, whereas in more recently most clutches have been found in water-lilies and flooded beds of calamus and bulrush. This change in nesting sites was apparently caused by the dying off of large areas of flooded reed beds in the last 30 years. In some inlets flooded reed beds completely disappeared. In 1998 the start of laying was clearly related to the nesting site: reed-breeders started significantly earlier than birds breeding in water-lilies and beds of calamus and bulrush. O~ving to the change in nesting sites during the last 10 years, we observed a time-shift in the reproduction: today Grebes start laying almost 50 days later than in the 80s. Moreover, we recorded a significant difference in the stability of nests related to the nesting site: nests in reed beds and bulrush had a higher stability than those in water-lilies and beds of calamus. The present findings are discussed in the light of reproductive decisions and reproductive successes. ZusammenfassungAm Dfimmer, einem hypertrophen Flachsee in Nordwestdeutschland, sank der Brutbestand des Haubentauchers von fast 400 Paaren Mitte der 80er Jahre auf 40-120 Paare in den 90er Jahren ab. In der vorliegenden Studie wurde der Frage nachgegangen, ob dieser Rtickgang auf Ver~inderungen im Nahrungsangebot oder einem Mangel an geeigneten Nistpl~itzen zurtickzuffihren ist. Sowohl Kiemennetzf~inge als auch Elektrobefischungen w~ihrend der Brutzeit lassen den Schluss zu, dass an Nahrungsfischen kein Mangel besteht. Es wurden insgesamt 13 F...

Escalating conflicts between grassland farming and wintering geese in northern Germany stimulated a long‐term study in order to promote a fair and workable system of compensation of harvest loss. Between 1996 and 2018 standardized experiments were carried out to quantify changes in yield loss and herbage quality. Simultaneously, we weekly monitored the number of geese to relate yield losses to goose numbers and to identify the impact of the different species. Exclosure experiments were established on conventionally managed grasslands. The number of investigated fields differed over the study period (1990s: n = 6, 2000s: n = 14, 2010s: n = 2–18). On each field, we established 12 marked plots (4.5 m2), six with exclosures from early November until the first cut of grass in May and six with access for the geese. In all plots dry biomass and the quality of herbage (contents of energy, crude protein, crude fibre and ash) were determined at first and second harvest. The total goose‐dependent yield losses at first harvest increased from 15% in the year 1996/97 to 50% at the end of the 2010s. The increase corresponds with changes in the maximum numbers and the migratory behaviour of the barnacle goose Branta leucopsis. Yield reductions correlated positively with densities of barnacle geese present in April. In contrast, we found no decline in grassland yields with increasing numbers of greater white‐fronted geese Anser albifrons. In all periods second harvest was not affected. The combined maximum number of both geese which were counted over approximately 23,000 ha of grasslands increased until 2002/03 but levelled off with numbers around 100,000 birds thereafter. While the maximum wintering population of greater white‐fronted geese dropped since 2007/08, the maximum number of barnacle geese increased until mid of 2010s. An increasing proportion of barnacle geese delayed their departure until May. Within each year grazed plots possessed higher energy and crude protein contents than ungrazed controls, suggesting that the geese maximize their potential nutrient intake rate by grazing. Synthesis and applications. The present study reveals a significant increase in goose‐related loss of grassland yields which form the basis for a fair and comprehensible system of compensation payments to affected farmers.

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