Estimating the abundance of mouse populations of known size: promises and pitfalls of new methods.

Knowledge of animal abundance is fundamental to many ecological studies. Frequently, researchers cannot determine true abundance, and so must estimate it using a method such as mark-recapture or distance sampling. Recent advances in abundance estimation allow one to model heterogeneity with individual covariates or mixture distributions and to derive multimodel abundance estimators that explicitly address uncertainty about which model parameterization best represents truth. Further, it is possible to borrow information on detection probability across several populations when data are sparse. While promising, these methods have not been evaluated using mark-recapture data from populations of known abundance, and thus far have largely been overlooked by ecologists. In this paper, we explored the utility of newly developed mark-recapture methods for estimating the abundance of 12 captive populations of wild house mice (Mus musculus). We found that mark-recapture methods employing individual covariates yielded satisfactory abundance estimates for most populations. In contrast, model sets with heterogeneity formulations consisting solely of mixture distributions did not perform well for several of the populations. We show through simulation that a higher number of trapping occasions would have been necessary to achieve good estimator performance in this case. Finally, we show that simultaneous analysis of data from low abundance populations can yield viable abundance estimates.     

Achondrogenesis type II (Langer–Saldino) in association with jugular lymphatic obstruction sequence

The prenatal diagnosis of achondrogenesis in association with cystic hygroma is described. Ultrasound findings of severe short-limbed dwarfism, decreased vertebral ossification, and normal ossification of the calvarium were all consistent with achondrogenesis type II. Although the unusual finding of associated cystic hygroma raised the suspicion of a concurrent chromosome abnormality, the karyotype of both fetal lymphocytes and fetal fibroblasts was normal. Autopsy confirmed dilated lymphatic channels in the basal endothelial layer of the skin, cystic hygroma, and coarctation of the aorta. Although previously unreported, we suggest that the features of this case of achondrogenesis indicate an association with lymphatic stasis and jugular lymphatic obstruction sequence in this syndrome.     

Plant Succession, Landscape Management, and the Ecology of Frugivorous Birds in Abandoned Amazonian Pastures

From towers constructed at the interface between second-growth forest and an active and an abandoned pasture, we observed inter-habitat movements of fruit-eating birds in eastern Amazônia. The abandoned pasture was composed of grasses and forbs with a scattering of shrubs and small trees. The active pasture contained a low, uniform bed of grass. A total of 47 frugivorous bird species was recorded in the second-growth forest. We observed that 18 of these species frequented the adjacent abandoned pasture but only 3 were found in the adjacent active pasture. Fruit-eating birds flying from second-growth forest typically spent only a few minutes in the abandoned pasture, and their movements were generally restricted to a pasture belt of 1–80 m along the border with the second-growth forest. Most inter-habitat movement occurred during the rainy season, which coincided with a peak in fruit availability in the abandoned pasture. Just three bird species, Ramphocelus carbo, Tachyphonus rufus , and Thraupis episcopus , accounted for an estimated 70% of the total movement of frugivores between the second-growth forest and the abandoned pasture. All three species spent most of their time in the abandoned pasture foraging on shrubs and trees but exhibited differences in their preference for specific habitat elements and in their seed-defecation habits. An understanding of bird behaviors in altered landscapes provides important information to planners and policy makers concerned with protecting regional biodiversity and maintaining landscape integrity. This research provides a rationale for placing limits on the size of clearings in the Brazilian Amazon.     

Adaptive Management and Climate Change Adaptation: Two Mutually Beneficial Areas of Practice

Adaptive management (AM) is a rigorous approach to implementing, monitoring, and evaluating actions, so as to learn and adjust those actions. Existing AM projects are at risk from climate change, and current AM guidance does not provide adequate methods to deal with this risk. Climate change adaptation (CCA) is an approach to plan and implement actions to reduce risks from climate variability and climate change, and to exploit beneficial opportunities. AM projects could be made more resilient to extreme climate events by applying the principles and procedures of CCA. To test this idea, we analyze the effects of extreme climatic events on five existing AM projects focused on ecosystem restoration and species recovery, in the Russian, Trinity, Okanagan, Platte, and Missouri River Basins. We examine these five case studies together to generate insights on how integrating CCA principles and practices into their design and implementation could improve their sustainability, despite significant technical and institutional challenges, particularly at larger scales. Although climate change brings substantial risks to AM projects, it may also provide opportunities, including creating new habitats, increasing the ability to quickly test flow‐habitat hypotheses, stimulating improvements in watershed management and water conservation, expanding the use of real‐time tools for flow management, and catalyzing creative application of CCA principles and procedures.     

The Optimization of Methods for the Collection of Aerosolized Murine Norovirus

Globally, norovirus is the most common gastroenteritis causing pathogen. Annually, norovirus causes 685 million cases of acute gastroenteritis and 200,000     

Simple models of massive epidemics of herpesvirus in Australian (and New Zealand) pilchards.

In March 1995, a mass mortality of pilchard started to occur in South Australia. This spread very rapidly throughout the Australian pilchard's range, later reaching New Zealand. In November 1998, a similar mass mortality broke out in South Australia and also spread, at a slower rate, throughout the Australian range. The mortality appeared to be caused by a herpesvirus. The mortality spread as a classical epidemic front, but its speed of progress and the brief duration of mortalities at a given location are extreme. We apply simple epidemic modelling techniques, SIR and SEIR modelling, to examine the factors behind the spread of this mortality and the differences between the 1995 and 1998/9 epidemics. We discuss biological factors influencing the critical processes of long-distance (D) and local (beta) transmission of infection.     

State-Space Modeling of the Relationship between Air Quality and Mortality

ABSTRACT

A portion of a population is assumed to be at risk, with the mortality hazard varying with atmospheric conditions including total suspended particulates (TSP). This at-risk population is not observed and the hazard function is unknown; we wish to estimate these from mortality count and atmospheric variables. Consideration of population dynamics leads to a state-space representation, allowing the Kalman Filter (KF) to be used for estimation. A harvesting effect is thus implied; high mortality is followed by lower mortality until the population is replenished by new arrivals.

The model is applied to daily data for Philadelphia, PA, 1973-1990. The estimated hazard function rises with the level of TSP and at extremes of temperature and also reflects a positive interaction between TSP and temperature. The estimated at-risk population averages about 480 and varies seasonally. We find that lags of TSP are statistically significant, but the presence of negative coefficients suggests their role may be partially statistical rather than biological. In the population dynamics framework, the natural metric for health damage from air pollution is its impact on life expectancy. The range of hazard rates over the sample period is 0.07 to 0.085, corresponding to life expectancies of 14.3 and 11.8 days, respectively.     

Identification of Conservation-Worthy Areas in Northern Zululand, South Africa

Abstract: We used spatial and statistical analyses to identify and prioritize broad areas for conservation attention in the northern Zululand region of KwaZulu-Natal, South Africa. We attempted to identify conservation-worthy areas based on species, vegetation types, ecological processes, and threats to biodiversity. Information on species was limited and so could not form the basis of the analysis. Priority vegetation types were identified by degree of endemicity, extent of protection and transformation, and degree of fragmentation. These priority vegetation types and threats to biodiversity were used to define broad linkages between existing protected areas. We set a goal of 10% protection for each vegetation type and 25% for each species. We identified several important (endemic or threatened) animal species and predicted their ranges using a simple model. Species ranges and their hotspots were compared with the distribution of protected areas and the suggested linkages to evaluate increased species representation. Generally, the eastern part of the study area was well protected. Unprotected conservation-worthy areas under greatest threat lay in the west, and protecting these areas is a priority. Furthermore, several vegetation types were not protected by provincial authorities, a situation that also needs to be addressed. The findings of our study need to be reassessed at a finer land-parcel scale, and implementation of a range of land-use options considered.     

Evaluating Post-wildfire Vegetation Regeneration as a Response to Multiple Environmental Determinants

Vegetation regeneration in post-fire environments varies across the landscape of a burned area. Variations are caused by interacting factors, including soil properties, vegetation characteristics, hydrology, land management history, and burn severity. While many of these factors have been explored previously, few studies have investigated the combination of multiple factors. A time-series of the remotely sensed enhanced vegetation index data has been analyzed to estimate rates of regeneration across a burn in central Arizona. We used regression trees to evaluate post-fire vegetation response as a function of multiple factors. Regeneration was a function of elevation (likely a proxy for moisture availability), burn severity, pre-burn vegetation, and post-burn management activities. Both time-series vegetation data and regression trees were valuable tools for determining dominant interacting factors responsible for variations in post-fire regeneration. Evaluation of the time-series data and modeled post-fire vegetation permitted the interpretation of management actions across the burned area.     

Dam Design can Impede Adaptive Management of Environmental Flows: A Case Study from the Opuha Dam, New Zealand

The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m³ s^?1 only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m³ s^?1 (compared to 19 times >100 m³ s^?1 and 6 times >203 m³ s^?1 in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows.