Behavioral Ecology and Interindividual Distance of Woolly Monkeys (Lagothrix lagothricha) in a Rainforest Fragment in Colombia

Abstract

Woolly monkeys have been considered vulnerable to forest fragmentation. However, we found a population of woolly monkeys that has been living in a small forest remnant in Colombian Amazonia, raising questions about which factors determine the persistence or extinction of woolly monkeys in fragmented forests. The main purpose of this investigation was to describe the behavioral ecology of woolly monkeys (Lagothrix lagothricha) in a 136-ha forest fragment in Guaviare, Colombia. We recorded activity patterns, diet, and use of space for three monkey troops by instantaneous sampling on focal animals, and we quantified interindividual distance, between January and December 2008. This group of woolly monkeys spent on average 31.7 % of their time feeding, 32.4 % resting, 34.2 % moving, and 1.8 % in social interactions. Their main feeding items were fruits (57.2 %), followed by leaves (15.5 %), arthropods (15.8 %), seeds (5.2 %), flowers (5.1 %), and others (1.2 %). The three most used plant families for fruit consumption were Moraceae (23.4 %), Fabaceae (16.3 %), and Ulmaceae (8.3 %), and the most important species was Ampelocera edentula (Ulmaceae). We estimated an average daily travel distance of 2,339 m and a home range of 126 ha. We found a negative relationship between the degree of interindividual distance and group size. Most of the studied ecological parameters were within the reported ranges for woolly monkeys in undisturbed habitats. Thus, our evidence indicates that their persistence in fragments does not require drastic behavioral changes. We suggest that fragmentation represents a threat to woolly monkeys when (1) fragments are not productive enough to sustain the population and/or (2) when it leads to a higher hunting pressure on the population.

Appendix 13.1

Statistical comparisons of activity (a), and diet (b), between different age/sex classes in three groups of woolly monkeys inhabiting a fragment in Colombian Amazonia. The monthly variation in diet is also shown (c; adult male = AM; adult female = AF; adult female dependent infant = AFI)

	L group	M group	S group
Activity budgets among age/sex classes (Z test for two proportions: ANOVA and Kruskal–Wallis test)
Feeding
AM vs. AF	Z = 0.657; P = 0.453	Z = 0.495; P = 0.582	Z = − 0.207; P = 0.802
AM vs. AFI	Z = 2.689; P = 0.006*	Z = 0.385; P = 0.652	Z = 0.129; P = 0.880
AF vs. AFI	Z = 2.085; P = 0.031*	Z = 0.892; P = 0.395	Z = 0.369; P = 0.652
Resting
AM vs. AF	Z = − 0.061; P = 0.960	Z = 0.644; P = 0.515	Z = 0.866; P = 0.342
AM vs. AFI	Z = 1.857; P = 0.062	Z = − 0.178 P = 0.802	Z = 0.173; P = 0.802
AF vs. AFI	Z = 1.86; P = 0.051	Z = 0.46; P = 0.582	Z = 0.424; P = 0.652
Moving
AM vs. AF	Z = 0.657; P = 0.453	Z = 0.579; P = 0.515	Z = 0.489; P = 0.582
AM vs. AFI	Z = − 0.076; P = 0.960	Z = − 0.429; P = 0.0.652	Z = 0.138; P = 0.880
AF vs. AFI	Z = 0.514; P = 0.582	Z = − 0.116; P = 0.880	Z = 0.138; P = 0.880
I. Socials	F = 0.26; df = 2; P = 0.26	F = 1.13; df = 2; P = 0.36	X2 = 1.50; df = 2; P = 0.17
Diet composition between the age/sex classes (Z test for two proportions)
Mature fruits
AM vs. AF	Z = 0.416; P = 0.652	Z = 0.396; P = 0.652	Z = 0.730; P = 0.453
AM vs. AFI	Z = 1.32; P = 0.177	Z = 0.261; P = 0.726	Z = 0.591; P = 0.582
AF vs. AFI	Z = 1.759; P = 0.080	Z = − 0.166; P = 0.802	Z = − 0.139; P = 0.880
Seeds
AM vs. AF	Z = 0.626; P = 0.515	–	–
AM vs. AFI	Z = 0.844; P = 0.359	–	–
AF vs. AFI	Z = 0.301; P = 0.726	–	–
Young leaves
AM vs. AF	Z = 0.147; P = 0.880	Z = − 0.339; P = 0.726	Z = 0.148; P = 0.880
AM vs. AFI	Z = 1.112; P = 0.250	Z = − 0.198; P = 0.802	Z = 0.460; P = 0.582
AF vs. AFI	Z = 1.436; P = 0.147	Z = − 0.259; P = 0.726	Z = 0.075; P = 0.880
Arthropods
AM vs. AF	Z = − 0.293; P = 0.802	Z = 0.199; P = 0.802	Z = − 0.187; P = 0.802
AM vs. AFI	Z = 0.185; P = 0.802	Z = 0.075; P = 0.880	Z = − 0.144; P = 0.880
AF vs. AFI	Z = 0.2; P = 0.802	Z = − 0.262; P = 0.726	Z = − 0.366; P = 0.652
Flowers
MA vs. FA	Z = 0.207; P = 0.802	–	Z = − 0.380; P = 0.652
MA vs. FAI	Z = 0.123; P = 0.0.880	–	Z = − 0.545; P = 0.582
FA vs. FAI	Z = − 0.382; P = 0.726	–	Z = − 0.435; P = 0.652
Temporal variation in diet composition (ANOVA and Kruskal–Wallis test)
Mature fruits	F = 4.678; df = 11; P = 0.001*	F = 2.778; df = 3; P = 0.075	F = 4.351; df = 7; P = 0.002*
Seeds	F = 4.703; df = 11; P > 0.001*	–	X2 = 11.865; df = 7; P = 0.105
Young leaves	F = 2.351; df = 11; P = 0.021*	F = 1.232; df = 3; P = 0.331	F = 1.679; df = 7; P = 0.150
Arthropods	F = 3.418; df = 11; P = 0.001*	F = 1.039; df = 3; P = 0.402	F = 0.580; df = 7; P = 0.767
Flowers	F = 4.309; df = 11; P > 0.001*	–	F = 2.956; df = 7; P = 0.017*

1. * Significant differences