A demographic analysis of mice population response to manipulation of adult males.

GOMEZ DANIELA; PRIOTTO JOSÉ; POLOP JAIME

Mendoza

Congreso; The 10 th International Mammalogical Congress; 2009

<!-- /* Font Definitions */ @font-face {font-family:Helvetica-Narrow; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-alt:"Arial Narrow"; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-format:other; mso-font-pitch:auto; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Adults play an important role influencing the survival and/or reproduction of juvenile in many species of mammals. We provide a demographic analysis of the effect the experimental removal of adult males has on population growth rates of Calomys venustus enclosed populations. The study was carried out in four 0.25-ha enclosures (two controls and two experimentals), each situated on natural pastures. This study was conducted between September 1997 and May 1998. Adult males were removed after offspring from the first litter were born. Weekly trapping sessions were carried out from November (Spring) to May (Autumn). In order to estimate population growth rates (?), apparent survival (?) and recruitment rates (1-?) were estimated using capture-mark-recapture models. Several models were constructed with these two parameters and the recapture probability (p) constrained to vary as a function of time, enclosure and/or treatment. We derive estimates of population growth rates through the estimates of ? and ?. The best models did not show treatment effect. Variability between the four enclosures was greater than between both control and both experimental enclosures. Survival was constrained only by enclosures. Although recruitment varied by time and enclosures, an earlier peak (late spring) in recruitment rates was observed in control enclosures. In experimental enclosures recruitment rates were higher in summer. Enclosures had different growth rates at the beginning but were equalled at the end of the study. Temporal variation in population growth rates was a result of temporal variation of recruitment rates. The two control enclosures showed the highest growth rates earlier in time. The effect of the onset of reproductive activity of juvenile female on population growth patterns is discussed. A more controlled study should be conducted using greater sample sizes in order to reduce the variability among replicates.