Naming, listing and measuring human-induced threats in protected areas are crucial in conservation. Here, we defined a check-list of direct threats in a Mediterranean remnant wetland (central Italy), managed as nature reserve, grouping them according to a taxonomically-oriented nomenclature. We assessed three regime parameters (scope, severity, and magnitude) applying an experience-based method, then comparing the assessments obtained from two different level of expertise: a panel of independent people, upper level ''university students'' in an applied ecology class; and a panel of ''experts'' as nature reserve biologists and managers. Despite observing a significant correlation among values assigned from students and experts for each regime parameter, students underestimated the scope of feral dogs, the severity of fires and the magnitude of feral dogs and water stress. Considering only the magnitude values (sum of scope and severity), students assigned the higher values to alien species, antropophilous species, aircraft, and pollution, while the experts assigned the higher values to antropophilous species, aircraft, alien species, and water stress. In an order of priority, there was an agreement between students and experts with a coincidence for three threats out of four. We suppose that a panel of students with a short academic training could be useful to a get a first order of priority in regard to a set of local selected threats, with much similarity to the assessment obtained from a panel of experts. When threat metrics are difficult to compare, experience-based approach obtained from technicians trained ad hoc (''students'') could be useful to define priorities for management strategies in nature reserves, but data obtained should be
Aspects of coexistence between the dwarf crocodile Osteolaemus tetraspis and the Nile monitor lizard Varanus niloticus were studied in swamp rain forests of south-eastern Nigeria, central Africa. Crocodiles were signi®cantly smaller than monitor lizards. There was no signi®cant sexual size dimorphism in the examined sample of Varanus, whereas the female size exceeded the male size in Osteolaemus. The food niche breadth was narrower in young than in adults of both species, and V. niloticus showed a narrower niche breadth than O. tetraspis. Crabs constituted the main prey type category for both species, whereas vertebrates were more rarely preyed upon. The diet composition of males and females was similar in V. niloticus, but it was different in O. tetraspis. The general diet composition of the two species was similar (78.2% of overlap), and even the habitats where these two species were found were similar. These interspeci®c similarities suggest that O. tetraspis and V. niloticus could be potential competitors in the freshwater ecosystems of the Nigerian rainforest. However, it is suggested that the main prey type for these species (crabs) is not limited in the environment, which may minimize interspeci®c competition. Interference competition can also occur between these species, as suggested by one case of direct predation of the one species (V. niloticus) towards the other species (O. tetraspis). A case of cannibalism was observed in V. niloticus. This could indicate that intraspeci®c competition can be important for regulating the dynamics of monitor populations in the rainforests of south-eastern Nigeria.
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