Assessing African Vultures as Biomonitors and Umbrella Species

African vulture populations are rapidly declining, yet funding and other resources available for their conservation are limited. Improving our understanding of which African vulture species could best serve as an umbrella species for the entire suite of African vultures could help conservationists save time, money, and resources by focusing their efforts on a single vulture species. Furthermore, improving our understanding of the suitability of African vultures as biomonitors for detecting environmental toxins could help conservation authorities to detect changes in ecosystem health. We used a systematic approach based on criteria selected a priori to objectively evaluate the potential of each of the 10 resident African vulture species as (i) an umbrella species for all of the African vulture species, and (ii) an avian biomonitor. For each criterion, we scored the respective African vulture species and summed the scores to determine which species was best suited as an umbrella species and as an avian biomonitor. Our results showed that, overall, certain aspects of vulture ecology (large population sizes, large body sizes, long lifespans, and their ability to be monitored over numerous seasons) support their suitability as biomonitors, while other ecological traits, including their diets and the public's perceptions of vultures, could diminish their suitability. The White-backed Vulture (Gyps africanus) was the best fit of the 10 vulture species in our assessment as both an avian biomonitor and an umbrella species for all African vulture species. Meanwhile, significant knowledge gaps for other species inhibit their utility as biomonitors. Due to their large home-range sizes, African vultures may only be useful as biomonitors at a regional scale. However, there could be value in using the White-backed Vulture as an umbrella species, as an aid to conserve the entire suite of African vulture species.

Movement patterns and home range in Diplomystes camposensis (Siluriformes: Diplomystidae), an endemic and threatened species from Chile

ABSTRACT We document movement patterns and home range of Diplomystes camposensis, an endemic and threatened freshwater catfish from Chile. We tracked the movements of seven individuals of different body size (13.5 to 19 cm SL) using portable radio telemetry equipment to investigate movement patterns in relation to day/night activity and habitat use in the San Pedro River (Valdivia Basin). Tracked movements and model-based analyses revealed that D. camposensis has a large home range and high mobility. The average home range was 0.068163 ± 0.033313 km2, and the average area of higher activity was 0.005646 ± 0.011386 km2. The mean linear home range was 387.4 m. The results also showed that movements were longer during the night, supporting nocturnal habits. Movements tended to be in an upstream direction for some individuals, although these differences were not significant when data was pooled. Large home range and movements suggest that the species may require large river areas to meet ecological demands, an aspect that could be severely affected by fragmentation. These results, along with previously published genetic data, suggest that the conservation of D. camposensis would be seriously threatened by hydromorphological alterations (e.g. lack of connectivity), such as those resulting from dam building.

Socio-spatial organization and spatial ecology

Home ranges of males (1204 km2) and females (1510 km2) were similar. Female home range size was positively related to the dispersion of prey and generally, but not exclusively, they displayed home range fidelity. Overlap between female home ranges was extensive, although they rarely met up. Male home ranges overlapped extensively and there was no difference in size between coalition and single males. Males overcame the problem of scent marking a large home range by concentrating scent marks in core areas. Generally female cheetah home range size is affected by resource productivity, although where prey are migratory, or in fenced reserves where movements are constricted, and areas where disturbance is severe, this may be different. Southern Kalahari males apparently need large home ranges to increase the likelihood of locating wide-ranging and sporadically receptive females. Mean dispersal distance for subadult males (96 km) was further than for females (39 km).

Short-term tracking of three red foxes in the Simpson Desert reveals large home-range sizes

The red fox (Vulpes vulpes) is probably the most intensively studied introduced predator in Australia, but little is known about its movements in arid areas. Here, we report on the home-range sizes of one male and two female red foxes that were tracked for 2–8 months using collars fitted with ARGOS transmitters in the Simpson Desert, central Australia. Based on the 100% Minimum Convex Polygon method, home-range sizes were 5723 ha, 50 158 ha, and 12 481 ha, respectively. Based on the 95% kernel contour method, home-range sizes were 3930 ha, 26 954 ha, and 12 142 ha, respectively. These home-range sizes are much larger than any recorded previously from elsewhere in Australia, suggesting that red foxes in the Simpson Desert need to roam over extensive areas to find enough resources to meet their energetic needs. Given that predation by red foxes poses a key threat to many small and medium-sized native mammals, we suggest that red fox control operations may need to be undertaken at very large spatial scales to be effective in arid areas.

Abundance and frugivory of the toco toucan (Ramphastos toco) in a gallery forest in Brazil's Southern Pantanal

Unlike other toucan species, the Toco toucan (Ramphastos toco) - the largest Ramphastidae - usually inhabits dry semi-open areas. This conspicuous canopy frugivore uses a large home range that includes a variety of vegetation types, among which gallery forests are widely cited as important to this species. However, the factors relating to the occurrence of Toco toucans in such habitats are unclear. I studied the abundance of Toco toucans as well as the availability of fleshy fruit in a gallery forest in the southern Pantanal (sub-region of Miranda, Brazil), in order to assess the relationship between these parameters. Also, I examined toucan foraging activity to analyze its relationship with both toucan abundance and fruit availability. The presence of the Toco toucan was more common in the gallery forest from the middle to the end of the dry season and during the middle of the wet season. Toucans foraged for fleshy fruits, mainly Genipa americana, Ficus luschnatiana, and Cecropia pachystachya fruits, feeding mostly on G. americana (by far the favorite food resource) and F. luschnatiana fruits during the dry season, while C. pachystachya fruits were important in the wet season. Toco toucans foraged particularly heavily (> 80% of foraging activity) on G. americana fruits during the latter part of the dry season, when fleshy fruit availability declined sharply. Toco toucan abundance in the gallery forest was associated with the availability of the most commonly consumed fleshy fruits, and also with its foraging activity. This finding suggests that the Toco toucan moved to the gallery forest periodically in response to the availability of abundant food resources, especially the G. americana fruits widely available and exploited during the severely dry season. Therefore, these fruits potentially contribute to Toco toucan persistence in the South Pantanal during the harshest period of the year.

Activity and home range of Testudo hermanni in Northern Italy

We describe the behavioral adaptations of a population of Hermann's tortoise to the climate of a northern sector of its range, and to a wooded biotope that is uncommon for the species. The activity, the home range, and the thermal relations along the daily and the yearly cycle are described. In contrast to other populations that have bimodal activity peaking in spring and in autumn, the tortoises in our study area had unimodal seasonal activity that can be related to lower summer temperatures. Home range size, 7.4 ha for females and 4.6 ha for males in our study area, was from three to seven times larger than that of all other populations. The large home range, and the low population density of the tortoises in our study area, may be due to food scarcity in the wooded habitat.

Movement patterns of female feral camels in central and northern Australia

Movement patterns of female feral camels were studied over four years (February 1993 to December 1996) in central and northern Australia using satellite telemetry. Areas used over 12-month periods (calculated using the fixed kernel method) were large (449–4933 km 2 ) and increased with increasing aridity as measured by long-term mean annual rainfall. No consistent pattern of variation was detected in movement rates of camels across seasons. Data collected over several years are needed to classify movements in feral camels. The only telemetered camel that has been monitored for longer than two years (this study) appeared to move within a large home range over the concluding 3.5 years that it was tracked. Because the areas used are large, extensive buffer zones will be needed in arid regions to protect environmentally sensitive areas from the impacts of feral camels.

Differential scaling of home-range area to daily movement distance in two African tortoises

Movements of the tortoises Geochelone pardalis (mean body mass 4.0 kg) and Kinixys spekii (0.62 kg) were studied by thread-trailing. The mean daily movement distance of G. pardalis was 435 m, and the short-term home-range area was 26 ha. The values for K. spekii were 172 m and 1.9 ha, respectively. The area used by G. pardalis was significantly larger than would be produced by scaling up the movements of K. spekii in the same geometric pattern. Home-range areas were about the same size (K. spekii) or several times as large (G. pardalis) as those predicted for mammals of equal body mass. Ingestion of soil for sodium may be a factor determining the large home range of the purely herbivorous G. pardalis. These tortoises frequented a small area of strongly sodic soil from which they dispersed over long distances.