Variation in Surrogate Breeding Habitat Quality Between Continuously Grazed Rangelands and Late-Cut Hayfields for a Threatened Grassland Birds

Rangelands and hayfields provide a large portion of remaining surrogate habitat for many species of declining grassland birds in North America. We compared late-cut hayfields and continuously grazed pastures at low to moderate cattle densities for providing suitable breeding habitat in eastern Canada for the nationally threatened Bobolink (Dolichonyx oryzivorus). To examine the quality of both habitats, we conducted point counts and monitored 87 nests during the 2015 and 2016 breeding seasons. Bobolink abundance and daily survival rate (DSR) of nests were modeled sequentially by habitat and sex as a function of vegetation structure, prey availability, and agricultural management. Year and habitat were the strongest predictors of abundance. When analyzed separately for pastures and hayfields, vegetation height was most important for female abundance in pastures while pasture size was most important for males. Nests in hayfields had significantly higher daily survival (DSR = 0.98 ± 0.01) than nests in pastures (DSR = 0.94 ± 0.01). Nesting success was highest in hayfields with taller vegetation, while in pastures, no microhabitat variable showed a clear relationship with DSR. Within pastures, cattle stocking densities of ≤ 1 animal units (AU) · ha^? 1 were not related to DSR. This study provides evidence that late-cut hay is of highest quality, but that small-scale beef farms with low to moderate stocking densities are suitable targets for conservation efforts of Bobolinks in eastern North America.     

The impact of land use/land cover scale on modelling urban ecosystem services

Context

Urbanisation places increasing stress on ecosystem services; however existing methods and data for testing relationships between service delivery and urban landscapes remain imprecise and uncertain. Unknown impacts of scale are among several factors that complicate research. This study models ecosystem services in the urban area comprising the towns of Milton Keynes, Bedford and Luton which together represent a wide range of the urban forms present in the UK.

Objectives

The objectives of this study were to test (1) the sensitivity of ecosystem service model outputs to the spatial resolution of input data, and (2) whether any resultant scale dependency is constant across different ecosystem services and model approaches (e.g. stock- versus flow-based).

Methods

Carbon storage, sediment erosion, and pollination were modelled with the InVEST framework using input data representative of common coarse (25 m) and fine (5 m) spatial resolutions.

Results

Fine scale analysis generated higher estimates of total carbon storage (9.32 vs. 7.17 kg m^?2) and much lower potential sediment erosion estimates (6.4 vs. 18.1 Mg km^?2 year^?1) than analyses conducted at coarser resolutions; however coarse-scale analysis estimated more abundant pollination service provision.

Conclusions

Scale sensitivities depend on the type of service being modelled; stock estimates (e.g. carbon storage) are most sensitive to aggregation across scales, dynamic flow models (e.g. sediment erosion) are most sensitive to spatial resolution, and ecological process models involving both stocks and dynamics (e.g. pollination) are sensitive to both. Care must be taken to select model data appropriate to the scale of inquiry.

     

Habitat functional response mitigates reduced foraging opportunity: implications for animal fitness and space use

Context

Animals selectively use landscapes to meet their energetic needs, and trade-offs in habitat use may depend on availability and environmental conditions. For example, habitat selection at high temperatures may favor thermal cover at the cost of reduced foraging efficiency under consistently warm conditions.

Objective

Our objective was to examine habitat selection and space use in distinct populations of moose (Alces alces). Hypothesizing that endotherm fitness is constrained by heat dissipation efficiency, we predicted that southerly populations would exhibit greater selection for thermal cover and reduced selection for foraging habitat.

Methods

We estimated individual step selection functions with shrinkage for 134 adult female moose in Minnesota, USA, and 64 in Ontario, Canada, to assess habitat selection with variation in temperature, time of day, and habitat availability. We averaged model coefficients within each site to quantify selection strength for habitats differing in forage availability and thermal cover.

Results

Moose in Ontario favored deciduous and mixedwood forest, indicating selection for foraging habitat across both diel and temperature. Habitat selection patterns of moose in Minnesota were more dynamic and indicated time- and temperature-dependent trade-offs between use of foraging habitat and thermal cover.

Conclusions

We detected a scale-dependent functional response in habitat selection driven by the trade-off between selection for foraging habitat and thermal cover. Landscape composition and internal state interact to produce complex patterns of space use, and animals exposed to increasingly high temperatures may mitigate fitness losses from reduced foraging efficiency by increasing selection for foraging habitat in sub-prime foraging landscapes.

     

Book reviews

Food Quality Control, Foods of Animal Origin, by H. V. Hagstad and W. T. Hubbert, 1986. viii+148 pp. illustrated. Ames, The Iowa State University Press. £12.95. ISBN 0 8138 0702 6.

Animal Nutrition, by A. A. Bond, 1987. English edition. 540 pp, illustrated. Chichester, John Wiley & Sons. ISBN 0 471 90375 2.

Egg Quality—Current Problems and Recent Advances—Poultry Science Symposium 20, Edited by R. G. Wells and C. G. Belyavin, 1987. 302 pp. illustrated. London, Butterworths. £35.00. ISBN 0 470 00470 X.

The Microbiology of Poultry Meat Products, Edited by F. E. Cunningham and N. A. Cox, 1987. ix+359 pp. illustrated. Orlando, Florida, Academic Press. £54.00, $65.00. ISBN 0 12 199880 0.     

The use of the Objective Structured Clinical Examination (OSCE) in small-animal internal medicine and surgery

The Objective Structured Clinical Examination (OSCE) has been used extensively to evaluate clinical skill of medical students. This article reports on its adaptation to veterinary medicine.     

Altered homeostasis of extracellular matrix proteins in joints of standardbred trotters during a long-term training programme

This study evaluates how strenuous training, age and lameness influence the release of cartilage oligomeric matrix protein (sf-COMP), aggrecan and collagen type II into synovial fluid in 28 (19.5-40 months) Standardbred trotters (STB), during a long-term training programme (24 months). All the horses were trained by the same trainer and were healthy on entering the training programme. Synovial fluid (sf) from the left middle carpal joint in each subject was sampled every third month. Enzyme-linked immunosorbent assay was used to determine the concentrations of sf-COMP, sf-aggrecan and sf-collagen type II. Concentration of sf-COMP decreased with increasing age and total days of training. The concentration of sf-COMP was found similarly related to both age and total days of training, so they could not be differentiated. It was also shown that the concentration of collagen type II degradation products increased with total days of training. The study shows that extensive and long-term training programme induces metabolic changes in articular cartilage exemplified by reduced release and synthesis of COMP. This is most likely due to strenuous training leading to inappropriate load on the articular cartilage.     

Comment on "Ancient DNA from the first European farmers in 7500-year-old Neolithic sites"

On the basis of analysis of ancient DNA from early European farmers, Haak et al. (Reports, 11 November 2005, p. 1016) argued for the Paleolithic ancestry of modern Europeans. We stress that the study is more limited in scope than the authors claim, in part because not all of the skeletal samples date to the time of the Neolithic transition in a given area of Europe.