Domestic dogs as an edge effect in the Brasília National Park, Brazil: interactions with native mammals

Abstract

Edge effects are a well-known result of habitat fragmentation. However, little has been published on fragmentation, isolation and the intrusive influence from the surrounding matrix at the landscape level. The objectives of the present study are to evaluate the presence of dogs in the Bras´ılia National Park (BNP) in relation to habitat type and the influence from the surrounding matrix. In addition, this study examines the response of the native mammal fauna to the presence of dogs. Track stations were built along dirt roads in the BNP and subsequently examined for the presence or absence of tracks. We used a stepwise logistic regression to model the occurrence of five mammal species relative to habitat variables, with an a = 0.05 to determine whether to enter and retain a variable in the model. A simulation of each species occurrence probability was conducted using a combination of selected habitat variables in a resource selection probability function. Results indicate a negative relationship between distance from the BNP edge and the probability of dog occurrences. From an ecological perspective, the presence of dogs inside the BNP indicates an edge effect. The occurrence of the maned wolf was positively associated with distance from a garbage dump site and negatively associated with the presence of dog tracks. The maned wolf and giant anteater seem to avoid areas near the garbage dump as well as areas with dog tracks. There is no support for the possible existence of a feral dog population inside the BNP, but the effects of freeranging dogs on the wildlife population in such an isolated protected area must not be neglected. Domestic dog Canis familiaris populations and disease control programs should be established in the urban, sub-urban and rural areas surrounding the BNP, along with the complete removal of the garbage dump from the BNP surroundings.

Assemblage of medium and large size mammals in an urban Semideciduous Seasonal Forest fragment in Cerrado biome

“…Aside from these factors, there are also factors present related to the proximity of households and urban centers. Edge effects are present especially in urban fragments such as invasion of exotic and domestic species (Crooks & Soulé 1999, Crooks 2002, Lacerda et al 2009) and the existence of adverse effects to the fauna arising from human contact. Adverse effects include waste disposal, hunting increase, and transit of people (Chiarello 1999, Peres 2001, Michalski & Peres 2005.…”

“…The fragmentation processes have also caused the formation of vegetation fragments in urban areas in many places of the world (e.g. Crooks 2002, Fernández-Juricic 2002, Lacerda et al 2009). The impacts of habitat fragmentation limit the presence of various species in the fragment because they restrict the area of the fragment (Chiarello 1999, Michalski & Peres 2007.…”

“…In this scenario the fragments are important to conserve despite their size or location, because although they are small, they may have conservation value in increasing connectivity (e.g. Crooks 2002, Lacerda et al 2009, Sampaio et al 2010.…”

Threats to and viability of the giant anteater, Myrmecophaga tridactyla (Pilosa: Myrmecophagidae), in a protected Cerrado remnant encroached by urban expansion in central Brazil

“…The predictions derived from our simulations might be viewed as optimistic because we did not model scenarios evaluating other known threats to the giant anteater population in the study area, such as feral dogs (LACERDA et al 2009). It has been demonstrated that feral dogs cause an edge effect in the Brasília Parque Nacional de Brasília, and giant anteaters avoid the outer skirts of the park (LACERDA et al 2009).…”

“…It has been demonstrated that feral dogs cause an edge effect in the Brasília Parque Nacional de Brasília, and giant anteaters avoid the outer skirts of the park (LACERDA et al 2009). Dogs come from urban and suburban areas close to the park: stray dogs enter the park through a garbage dump located in the vicinity of the protected area (LACERDA et al 2009). Even though giant anteaters are hunted in certain areas (e.g., KOSTER 2008) there is no evidence of that they are hunted [by wild dogs] in the Parque Nacional de Brasília.…”