Applications of transition matrix models in forest dynamics: Araucaria in Papua New Guinea and Nothofagus in New Zealand

This paper describes the application of the Leslie matrix model to single species populations, and a similar transition matrix model to communities of more than one species. Examples are drawn from populations of Araucaria spp. in tropical rainforest in Papua New Guinea, and from Nothofagus fusca stands in temperate montane forest in New Zealand. Both species generally had λ values close to 1.0 (r, the intrinsic rate of natural increase ? 0) and in both cases predicted trends were consistent with other ecological information from the stands or elsewhere. Various possible sources of error and empirical tests of the sensitivity of the single species model and the accuracy of its predictions are described. It is concluded that, despite certain limitations, with careful interpretation these models constitute an important tool for the investigation of forest dynamics. The basic model may be modified in various ways, for example, to include vegetative reproduction, or put to use in practical problems such as defining a harvesting strategy for a forest tree species. In studies of succession involving long-lived species these models are particularly valuable, not only for predicting the magnitude and direction of future changes, but also because they suggest a time scale for the trends, and this can then be evaluated in the light of other knowledge about the communities in question. Moreover, the variability of λ values obtained for differen species relates to their life cycle strategies, so that by the use of Leslie matrices it may be possible objectively to rank the species of a community along the continuum of r to k strategies.     

Development of 19 microsatellite loci for Swainson's hawks (Buteo swainsoni) and other buteos

We developed 26 Swainson's hawk (Buteo swainsoni) microsatellite primers from CA, AAT, CATC and GAGAA enriched genomic libraries. Primers were tested in 357 Swainson's hawks from western North America as well as seven other Buteo species. These markers will have broad application in investigations of Buteo population structure and genetic diversity.     

Evidence of a Minimum Patch Size Threshold of Reproductive Success in an Endangered Songbird

ABSTRACT That area-sensitive songbirds breed only in relatively large patches suggests that there may be a minimum patch size threshold in which they will breed, even when controlling for the total amount of habitat in the landscape. We searched for minimum patch size thresholds of presence, territory establishment by males, pairing success, and reproductive success for 2 migratory songbirds that differed in sensitivity to patch size: golden-cheeked warblers (Dendroica chrysoparia) and white-eyed vireos (Vireo griseus). We assessed 2 potential limiting factors: brown-headed cowbird (Molothrus ater) parasitism and arthropod biomass (food resource). We determined whether either factor was related to patch size and compared measurements of each above and below the observed thresholds. We monitored 24 golden-cheeked warbler and 47 white-eyed vireo territories in 12 patches. We found evidence of a minimum patch size threshold (between 15.0 ha and 20.1 ha) of reproductive success for golden-cheeked warblers, but not for white-eyed vireos. We found no minimum patch size thresholds for presence, territory establishment by males, or pair formation for either species. Conservation practices based on thresholds of presence, territory establishment, or pair formation might not address issues of reproduction for golden-cheeked warblers. We failed to find evidence that cowbird parasitism or arthropod biomass were limiting factors. The ability to identify patch size thresholds of reproductive success for target species could be useful in conservation and management for setting goals for retention and restoration of target species’ habitat patch size.     

Monitoring Golden-Cheeked Warblers on Private Lands in Texas

ABSTRACT A majority of North American breeding habitat for neotropical migrants exists on private lands, requiring monitoring strategies focused on habitat in these private holdings. We outline study designs and protocols using repeated Presence-Absence surveys across a gradient of patch sizes to develop a range-wide monitoring program for the endangered golden-cheeked warbler (Dendroica chrysoparia) in Texas, USA. We surveyed 200–400 point-count locations across approximately 30 private properties annually from 2005 to 2008. We used data from our surveyed patches (n = 147) and the Ψ (occupancy), p (detection), and γ = 1 - ɛ parameterization to estimate patch dynamics and associated detection probabilities for golden-cheeked warblers. Patch size had a strong association with patch occupancy, and all patches >160 ha were predicted to be occupied. We found no evidence that large golden-cheeked warbler populations located on public lands in the vicinity of our study area influenced occupancy dynamics. We conducted simulations across a range of detection probabilities to evaluate potential sample sizes for both standard- and removal-based occupancy modeling. Simulations using parameter estimates from our analysis indicated that removal-based sampling is superior to standard sampling. Based on our results, surveying golden-cheeked warbler presence in oak-juniper (Quercus-Juniperus) patches under a removal modeling framework should be considered as one alternative for range-wide monitoring programs because patch-level monitoring would be necessary to estimate proportion of range occupied. Large contiguous patches are rare across the species’ range; hence, conservation and management of the mosaic of smaller patches within a landscape context would be required for maintaining species viability. Thus, we recommend the identification of areas where smaller, contiguous patches represent a significant portion of the available habitat within the local landscape and targeting these areas for habitat maintenance and improvement.     

ELECTRICAL STIMULATION OF HUMAN FUNGIFORM PAPILLAE

The experiment by Békésy (1964) on electricalstimulation of single, human, fungiform papillae was repeated.Békésy's results were confirmed, that each papillagives rise to only one gustatory quality, and that only thequalities of bitter, salty, sour, and sweet are reported. Inaddition, maps of the distribution of the papilla types weremade for two male and two female Ss. Data to support the existenceof quality groupings were found in only one S.     

The helminth parasites of the badger (Meles meles) in Cornwall

The helminth parasites of 118 badgers from Cornwall are recorded. Nematode infestations are common. The five species found are Capillaria? erinacei, Molineus patens, Uncinaria stenocephala, Aelurostrongylus falciformis and Strongyloides sp. Cestode infestations appear to be rare, the species recorded being Mesocestoides lineatus and Dilepis undula. Similarly only a single trematode, Ityogonimus lorum, is recorded.     

Honeybees and the nectar of Echium plantagineum L. in southeastern Australia

An account is given of the flower of Echium plantagineum in south-eastern Australia, including stages and timing of flowering, behaviour of raindrops in the flower and aspects of floral microclimate. The concentration of nectar solutes varied with time and site, with means varying from 2 to 62% (as g sucrose/100 g solution). There was a significant negative correlation between nectar solute concentration and ambient relative humidity: the drier the air, the more concentrated the nectar. Rates of nectar secretion per flower varied with the bagging method, with long-term bagging reducing net secretion rates, possibly because of re-absorption. Rates varied with time, day and site, with a temporal pattern of change suggesting a link between rates of photosynthesis and secretion. Maximum nectar secretion rates in short-term bagging experiments were ca. 300 μg sugar/flower/hr (equivalent to > 2 mglflower/24 hr). Secretion rate was correlated with flower density. As flower density increased, secretion rate per flower decreased; rate of sugar production per unit area increased relatively more slowly than flower density. E. plantagineum could produce > 500 mg sugar/m²/day. Honeybees foraged on E. plantagineum only at ambient air temperatures above ca. 17°C unless irradiance exceeded ca. 750 W m^-2. Foragers collected nectar or pollen alone, or both, with the type of visit significantly correlated with nectar solute concentration. Below 35% (as g sucrose/100 g solution) most bees took pollen only; above 40%, most took nectar. Mean standing crop of nectar was generally < 100 μg/flower when most bees were taking nectar, but could exceed 1000 μg/flower when bees were absent or foraging mainly for pollen. Honeybees did not always remove all nectar from flowers they probed. Reabsorption of residual nectar may augment the following day's secretion.