Title
Group Size Dynamics over 15+ Years in an African Forest Primate Community
Author(s)
Gogarten, J. F.;Jacob, A. L.;Ghai, R. R.;Rothman, J. M.;Twinomugisha, D.;Wasserman, M. D.;Chapman, C. A.
Published
2015
Publisher
Biotropica
Abstract
Group size affects many aspects of the ecology and social organization of animals. We investigated group size stability for five primate species in Kibale National Park, Uganda from 1996 to 2011 at three nested spatial scales. Survey data indicated that group sizes did not change for most species, with the exception of red colobus monkeys (Procolobus rufomitratus), in which group size increased at all spatial scales. Mangabey (Lophocebus albigena) group size increased in old-growth forest, but the sample size and increase were small. To augment this survey data, we collected several years of demographic data on three habituated groups of redtail monkeys (Cercopithecus ascanius), eight groups of black-and-white colobus (Colobus guereza), and one red colobus group. The red colobus group increased from 59 to 104 individuals, while redtail monkey and black-and-white colobus group sizes were stable, mirroring our survey results. To understand mechanisms behind group size changes in red colobus versus stability in other primates, we monitored forest dynamics at two spatial scales between 1990 and 2013, considered changes in predator population, and explored evidence of disease dynamics. The cumulative size of all trees and red colobus food trees increased over 24yr, suggesting that changing food availability was driving group size changes for red colobus, while predation and disease played lesser roles. Overall, our results and evidence of changing primate densities suggest that the Kibale primate community is in a non-equilibrium state. We suggest future conservation and management efforts take this into consideration. Muhtasari Idadi ya wanyama katika kundi inaweza kubadilisha ikolojia na jamii yao. Tulitaka kujua mabadiliko ya aina saba ya nyani katika hifadhi ya taifa Kibale, Uganda kuanzia mwaka 1996-2011. Tulihesabuukubwa wa makundi ya nyanikatika hifadhi na msitu uliokatwa na isuokatwa. Pia tulitaka kufahamu kama chakula kinacholiwa na nyani kinaelezea ukubwa wa kundi na mabadiliko ya ukubwawaaina ya miti katika maeneoya misitu isiyokatwa kuanzia 1990 mpaka 2013. Hakuna mabadiliko katika ukubwa wa makundi isipo kuwa mbega wekundu(Procolobus rufomitratus) ambao: waliongezeka kwa kawaida. Ukubwa wa makundi ya mangabey (Lophocebus albigena) iliongezeka katika msitu usiokatwa, lakini hakuwawa na wanyama wengi na ongezeko lilikuwa dogo. Kwa miaka kadhaa idadi ya wanyama imekuwa ikihesabiwa katika makundi mbalimbali ya nyani wasio ogopa watafiti: makundi matatu ya nyani wenye mkia mwekundu (Cercopithecus ascanius), makundi nane ya mbega wenye weusi na weupe (Colobus guereza) na kundi moja la mbega wekundu. Kundi la mbega wekundu liliongezeka mara mbili kwa ukubwa lakini makundi ya nyaniwenye mkia mwekundu na mbega wenye weusi na weupe hayakubadilika (kama matokeo ya jumla). Kwa ujumla, chakula cha tumbili katika msitu usiokatwa kiliongezeka kwa muda lakini ongezeko lilitofautiana kwa kila aina ya nyani.Kufahamu kwa nini makundi ya mbega wekundu yanakuwa makubwa wakati makundi ya nyani wengine hayawi makubwa, tulijadili madhara ya magonjwa na wanyama wanaokula nyama. Tunafikiri mabadiliko katika chakula yanaweza kuwa muhimu zaidi.Ni vigumu kuelewa ikolojia changamani ya kibale, hivyo utafiti zaidi unaitajika katika siku zijazo.
Keywords
forest dynamics;Kibale National Park;Uganda;non-equilibrium;Procolobus rufomitratus;red colobus;stability;kibale-national-park;red colobus monkeys;crowned hawk-eagles;old-growth forest;rain-forest;ecological constraints;chimpanzee;predation;cercopithecus-mitis;species composition;folivorous primate;Environmental Sciences & Ecology
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PUB15506