Intensive management fails to promote recruitment in the last large population of Juniperus communis (L.) in Flanders (Belgium)

In this study, the effectiveness of management measures aimed at promoting recruitment in the last large Flemish juniper population at Heiderbos is evaluated. We resurveyed demographic plots 23 years after their establishment in 1980 and linked the population changes with detailed records of the intensive management during the same period. Between 1980 and 2003 the population size has decreased by 36% and has changed from a relatively immature to a mature population with very few young individuals. Based on a simple model that simulated height growth between 1980 and 2003, the recruitment and mortality rates were estimated to be 5 and 24 ha⁻¹ yr⁻¹, respectively. Intensive management has thus not been able to promote recruitment and the population might go extinct within 40 years if these rates remain unchanged. Furthermore, some measures, notably the working of the soil, have increased mortality of established junipers. The reasons for the limited recruitment are not entirely clear yet, but it may be due to a combination of the limited availability of bare ground for germination and the extremely low viability of juniper seeds. The latter fact may be a common characteristic of many threatened juniper populations in northwestern Europe.     

Small forest patches as pollinator habitat: oases in an agricultural desert?

Landscape Ecology - Small forest fragments are often the most abundant type of semi-natural habitat in intensive agricultural landscapes. Wild pollinators can use these forest patches as nesting or...     

The effect of mass-flowering orchards and semi-natural habitat on bumblebee colony performance

Landscape Ecology - Bumblebees are important pollinators for agricultural crops and wild plants. However, agricultural intensification and loss of semi-natural habitat may have adverse effects on...     

Increased cartilage oligomeric matrix protein concentrations in equine digital flexor tendon sheath synovial fluid predicts intrathecal tendon damage

Objectives: To evaluate digital flexor tendon sheath (DFTS) synovial fluid cartilage oligomeric matrix protein (COMP) concentrations as a molecular marker for intrathecal pathology. Study Design: Case control study. Animals: Horses (n=46) with DFTS tenosynovitis; 23 fresh cadaver horses. Methods: DFTS synovial fluid samples were collected from clinical cases with noninfected DFTS tenosynovitis and from control DFTS. Clinical and surgical findings were recorded, and dissection of control limbs was performed to confirm the DFTS to be grossly normal. Synovial fluid COMP was quantified using a homologous competitive inhibition ELISA. Results: Abnormalities were identified tenoscopically: intrathecal tendon/ligament tearing was identified in 37 cases and 9 had other lesions. In control horses, synovial fluid COMP was higher in younger horses. Clinical cases with intrathecal tendon/ligament tearing had higher synovial fluid COMP than either clinical cases with other lesions, or controls. In horses ≥5 years old, the sensitivity and specificity of the assay was high for diagnosing intrathecal tendon/ligament tearing. Conclusions: COMP concentrations in DFTS synovial fluid were significantly greater than those in normal horses with noninfected tenosynovitis caused by intrathecal tendon/ligament tearing, but not by other lesions.     

Quantification of left ventricular longitudinal strain, strain rate, velocity, and displacement in healthy horses by 2-dimensional speckle tracking

Background: The quantification of equine left ventricular (LV) function is generally limited to short‐axis M‐mode measurements. However, LV deformation is 3‐dimensional (3D) and consists of longitudinal shortening, circumferential shortening, and radial thickening. In human medicine, longitudinal motion is the best marker of subtle myocardial dysfunction. Objectives: To evaluate the feasibility and reliability of 2‐dimensional speckle tracking (2DST) for quantifying equine LV longitudinal function. Animals: Ten healthy untrained trotter horses; 9.6 ± 4.4 years; 509 ± 58 kg. Methods: Prospective study. Repeated echocardiographic examinations were performed by 2 observers from a modified 4‐chamber view. Global, segmental, and averaged peak values and timing of longitudinal strain (SL), strain rate (SrL), velocity (VL), and displacement (DL) were measured in 4 LV wall segments. The inter‐ and intraobserver within‐ and between‐day variability was assessed by calculating the coefficients of variation for repeated measurements. Results: 2DST analysis was feasible in each exam. The variability of peak systolic values and peak timing was low to moderate, whereas peak diastolic values showed a higher variability. Significant segmental differences were demonstrated. DL and VL presented a prominent base‐to‐midwall gradient. SL and SrL values were similar in all segments except the basal septal segment, which showed a significantly lower peak SL occurring about 60 ms later compared with the other segments. Conclusions and Clinical Importance: 2DST is a reliable technique for measuring systolic LV longitudinal motion in healthy horses. This study provides preliminary reference values, which can be used when evaluating the technique in a clinical setting.