Ecology

ABSTRACT This study evaluated the relationship between body size and digestive tract characteristics of the important predatory freshwater fish Hoplias malabaricus, which is widely distributed in South America. The allometric coefficients were calculated for the mass and standard length (LS) relationships for two different LS groups: (1) between 20 and 100 mm (characterized as insectivores) and (2) >100 mm (characterized as piscivores). Differential growth measured from the allometric coefficient, b, between the insectivore (b < 3) and the piscivore (b > 3) groups was detected. Anterior intestine length and pyloric caeca zone length showed significant differences between groups. Two complementary hypotheses were developed to explain the differential growth: (1) H. malabaricus has a digestive tract adapted to a piscivorous diet, which is independent of its ontogenetic stage of development, and (2) the negative allometry observed in group 1 individuals agrees with a general behavioural strategy, allowing individuals to grow in LS during a shorter period of time.

We assessed the impacts of crop raiding by wild mammals on the livelihoods of smallholding farmers in south-western Ethiopia. Data were generated through participatory field mapping, interviews and focus groups. The results indicated that wild mammals, mainly olive baboons Papio anubis and bush pigs Potamochoerus larvatus, were raiding most crops cultivated in villages close to forests. In addition to the loss of crops, farmers incurred indirect costs in having to guard and cultivate plots far from their residences, sometimes at the expense of their children's schooling. Raiding also undermined farmers’ willingness to invest in modern agricultural technologies. Various coping strategies, including guarding crops and adapting existing local institutions, were insufficient to reduce raiding and its indirect impacts on household economies to tolerable levels, and were undermined by existing policies and government institutions. It is essential to recognize wild mammal pests as a cr...

Basic information required to conserve wild tigers Panthera tigris is lacking for the Bangladesh Sundarbans. The objectives of this study were therefore to estimate tiger home range size and obtain information on movement. Two adult female tigers were captured in the south-east of the Sundarbans and fitted with global positioning system collars. Mean home range sizes for the two tigers estimated with 95% minimum convex polygon and fixed kernel methods were 12.3 and 14.2 km2, respectively. A mean female home range size of 14.2 km2 would indicate a density for the south-east Sundarbans of seven adult females per 100 km2. The maximum distance moved by a tiger in 1 day was 11.3 km. Although preliminary these home range estimates indicate that the Sundarbans of Bangladesh has good quality tiger habitat relative to other tiger landscapes, highlighting the value of this mangrove ecosystem for the survival of this Endangered species.