Morphometric identification of small mammal footprints from ink tracking tunnels in the Brazilian Cerrado

Abstract

An alternative method for identifying and inventorying rodents and marsupials inhabiting forests and grasslands of Brazilian Cerrado is presented and discussed. Ink tracking tunnels were designed according to the size of target species and used to build a reference collection of small mammal footprints composed of 1408 footprints belonging to 251 individuals from 30 species (21 rodents and nine marsupials). Sherman traps and ink tracking tunnels were used to conduct inventories in gallery forests. Footprints obtained in ink tracking tunnels were digitalized and compared with those in reference collection using Discriminant Analysis (DFA). DFA allowed good footprint differentiation, even among congeneric species. In DFA analysis, the first two axis were related to size and arboreality. The efficiency of ink tracking tunnels was higher (track-success = 31%) than conventional trapping (trap-success = 14%) in inventories. Ink tracking tunnels gave a good description of the small mammal community of gallery forest by detecting rodents and marsupials of different habits, including trap-shy species. This paper also discusses advantages and limitations of ink tracking tunnels use in inventories and ecological studies, and concludes that this technique can be efficient in long-term studies and in rapid inventories as a complementary technique for trapping.

WSN in Conservation Management

“…The tunnels (Figure 1) are inexpensive and reasonably sensitive to the presence of rodents (particularly rats) when they are present at low densities less so with mustelids (weasels, ferrets and stoats) and possum. Wet weather and overtracking are key limitations of tracking tunnels, which can lead to data loss [11]. High population densities can lead to overtracking making identification of discrete footprints difficult.…”

“…These nodes are constrained by limited storage and power, similar to embedded systems. Numerous applications have been developed employing WSN technologies in many fields, including agricultural monitoring [7,11] and animal behaviour studies [8,13,14]. Figure 5 illustrates one of the commonly used WSN architecture in monitoring applications with sensor nodes, a sink node, a base station and a server.…”

Variação morfológica de pegadas de roedores arborícolas e cursoriais do Cerrado

“…As análises de morfometria geométrica foram realizadas utilizando a mesma coleção de referência de pegadas de pequenos mamíferos do Cerrado utilizada e identificada por PALMA & GURGEL-GONÇALVES (2007). Foram selecionadas as espécies de roedores com diferentes modos de locomoção e que apresentavam maior quantidade de pegadas para viabilizar a análise morfométrica (Tab.…”

“…Uma das formas dos roedores explorarem essa complexidade é por meio da segregação vertical, apresentando diferentes graus de arborealidade (NITIKMAN & MARES 1987). Entre as especializações para exploração de nichos arbóreos e terrestres, estão as modificações nas patas, que podem ser avaliadas estudando as pegadas (PALMA & GURGEL-GONÇALVES 2007).…”

“…O estudo das pegadas vem sendo feito nas últimas déca-das e representa uma ferramenta importante para inventários e estudos ecológicos de populações de mamíferos de maneira menos invasiva (MARTEN 1972, TAYLOR & RAPHAEL 1988, BECKER & DALPONTE 1991, CAREY & WITT 1991, BOONSTRA et al 1992, ALPEDOORN et al 1993, RATZ 1997, PALMA & GURGEL-GONÇALVES 2007. Em alguns desses estudos, a discriminação de pegadas entre espécies foi feita usando a morfometria tradicional como ferramenta, ou seja, a medição e quantificação de distâncias e/ou ângulos (MONTEIRO & REIS 1999).…”