Oncocercosis and its control in Equatorial Guinea: 1997-2010

BAN EK, 199

Data from: Spatial mismatch between management units and movement ecology of a partially migratory ungulate

1. Population-level management is difficult to achieve if wildlife routinely crosses administrative boundaries, as is particularly frequent for migratory populations. However, the degree of mismatch between management units and scales at which ecological processes operate has rarely been quantified. Such insight is vital for delimiting functional population units of partially migratory species common in northern forest ecosystems. 2. We combined an extensive dataset of 412 GPS-marked red deer (Cervus elaphus) across Norway with information on the size and borders of two administrative levels, the governmental level (municipality) and landowner level (local management units; LMUs) to determine the timing and scale of mismatch between animal space use and management units. We analysed how landscape characteristics affected use of management units and the timing and likelihood of crossing borders between them, in an effort to delineate more appropriate units in various landscapes. 3. Median municipality size could potentially cover 70% of female and 62% of male annual ranges, while only 12% and 4% of LMUs were expansive enough to accommodate migratory routes in females and males, respectively. Red deer migrate along elevational gradients and are more likely to find both suitable lowland winter habitat and higher summer habitat within management units with variable topography. Consistent with this, the likelihood of border crossing decreased with increasing diversity of elevations. 4. Synthesis and applications. We demonstrate a considerable mismatch between animal space use and management units. Far-ranging movements and frequent administrative border crossings during autumn migration coincides with the period of active management (hunting season). Our study also highlights that, due to extensive movements of males, coordination of management aims may provide a more realistic avenue than increasing sizes of local management units. A more general insight is that the degree of mismatch between range use and management units depends on the season and landscape type. This needs to be accounted for when delimitating functional population units of migratory populations

Effect of wind, thermal convection, and variation in flight strategies on the daily rhythm and flight paths of migrating raptors at Georgia's Black Sea coast

Every autumn, large numbers of raptors migrate through geographical convergence zones to avoid crossing large bodies of water. At coastal convergence zones, raptors may aggregate along coastlines because of convective or wind conditions. However, the effect of wind and thermal convection on migrating raptors may vary depending on local landscapes and weather, and on the flight strategies of different raptors. From 20 August to 14 October 2008 and 2009, we studied the effect of cloud development and crosswinds on the flight paths of raptors migrating through the eastern Black Sea convergence zone, where coastal lowlands at the foothills of the Pontic Mountains form a geographical bottleneck 5-km-wide near Batumi, the capital of the Independent Republic of Ajaria in southwestern Georgia. To identify key correlates of local aggregation, we examined diurnal variation in migration intensity and coastal aggregation of 11 species of raptors categorized based on size and flight strategies. As reported at other convergence zones, migration intensity of large obligate-soaring species peaked during the core period of thermal activity at mid-day. When clouds developed over interior mountains and limited thermal convection, these large obligate-soaring species aggregated near the coast. However, medium-sized soaring migrants that occasionally use flapping flight did not aggregate at the coast when clouds over the mountains weakened thermal convection. Numbers of alternate soaring-flapping harriers (Circus spp.) peaked during early morning, with these raptors depending more on flapping flight during a time of day with poor thermal convection. Small sparrowhawks (Accipiter spp.) aggregated at the coast during periods when winds blew offshore, suggesting aggregation caused by wind drift. Thus, weather conditions, including cloud cover and wind speed and direction, can influence the daily rhythm and flight paths of migrating raptors and, therefore, should be accounted for before inferring population trends from migration counts

Data from: Do migratory and resident birds differ in their responses to interacting effects of climate, weather and vegetation?

Aim: Knowledge of the individual and collective effects of habitat, weather variability, and climate on bird populations is limited, with the result that species vulnerability to the collective impacts of global change is poorly understood. We quantified the effects of interactions between these potential drivers on the occurrence of resident, migratory, and nomadic birds in Australian temperate woodlands. Location: A 1.8 million hectare temperate woodland belt in south-eastern Australia. Time period: 2002-2015. Major taxa studied: Temperate woodland birds. Methods: We used logistic mixed models to quantify the factors affecting the occurrence of three groups of birds (residents, partial migrants, nomads) at 203 long-term field sites located in three vegetation types (restoration plantings, natural regrowth woodland, old growth woodland) surveyed repeatedly between 2002 and 2015. Potential explanatory variables included vegetation type, three long-term climate variables (mean annual rainfall, maximum temperature, minimum temperature), and the three corresponding weather variables for 12 months preceding each survey. Results: We found four-way interactions between bird movement category, type of vegetation cover, and rainfall (both as a long-term climate variable and a short-term weather variable). Increased occurrence of nomads and partial migrants, but not resident species, was associated with high short-term rainfall. The effects were more marked in long-term climatically-wet areas, and also differed between vegetation types. Models for maximum and minimum temperature were simpler than those for rainfall, but showed evidence of partial migrants and nomadic species avoiding low minimum or high maximum temperatures in some vegetation types. Main conclusions: Our analyses revealed that birds with different movement patterns exhibit different responses to weather and long-term climate. Nomadic species in particular respond to rainfall strongly in climatically-wet locations (presumably because of large pulses in resources). Drying conditions resulting from climate change may therefore create problems for the future persistence of nomadic bird species