DOI: 10.5061/dryad.fn2z34tvd
title: Using retrospective life-tables to assess the effect of extreme climatic conditions on ungulate demography

description: In Mediterranean areas, severe drought events are expected to intensify in
 forthcoming years as a consequence of climate change. These events may
 increase physiological and reproductive stress of wild populations
 producing demographic changes and distribution shifts. We used
 retrospective life tables to understand demographic changes on a wild
 population after severe drought events. We studied the impact of two
 extreme events (2003 and 2005) on the population dynamics of our model
 species, the red deer (Cervus elaphus). During both years, population
 density was high (40 and 36 ind/100 hectares, respectively). Thus, we
 reconstructed retrospectively the age-structure of the female part of the
 population for the period 2000-2010 by using data of known-age individuals
 culled during the period 2000 to 2019 (n = 4176). Also, based on previous
 studies results, we aimed to validate this methodology. Both extremely dry
 years, 2003 and 2005, produced marked and lasting cohort effects on
 population demography. Age pyramid the following years (2004 and 2006)
 revealed that the extreme drought caused the female fawn cohort to be
 similar or even smaller than the yearling cohort. Furthermore, these
 cohort effects were still perceptible 3 years after theses severe events.
 Results agree with previous findings that showed a negative effect of
 severe drought events on female pregnancy rates and conception dates.
 Although simple, this study provides an empirical
 quantification of the demographic effects of severe drought
 events for a wild population which might be useful to understand future
 demographic changes under the context of climate change.
description: This
 database contains data on 4176 known-age females culled (or found dead)
 mostly from October to February during the years 2000-2019. These females
 were a random subsample of the popula­tion (i.e. no hunting selection was
 performed because of the objective was culling as much females as
 possible). For each
 individual culled, the first incisor (I<sub>1</sub>) was
 removed to assess its age, although for younger ones, still with milk
 incisors, the age was assessed by tooth replacement and succession method
 (Mitchell, 1967; Azorit et al., 2002a). Histological examinations of
 incisors were performed by staff at the Los Quintos de Mora’s laboratory
 by counting cementum annuli (Low & Cowan,
 1963; Azorit et al., 2002b). After
 extraction of the incisors, each tooth was placed into labeled plastic
 containers filled with water. They were left in the plastic containers for
 around four weeks to let the soft tissue rot away and thus, help
 eliminating any remaining soft tissues before decalcification.
 Subsequently, incisors were placed in a 5% nitric acid solution for two or
 three days (Morris, 1972). Once decalcified, each tooth root was placed in
 a cryostat where several longitudinal cuts of 25 μm were made at a
 temperature of -18ºC. The different sections were stained using diluted
 haematoxylin and then, several sections of each tooth were mounted on a
 glass microscope slide. Finally, the dental cementum annuli were count by
 using a 20x magnification microscope (ZEISS MC 100).
description: This database has 3 columns:
 DATE_CAPTURE indicates the date when females were culled
 (mm/dd/yyyy) AGE: The age of females in years (ranging
 from 0-15 years). SEX: Sex is always
 "Female"