DOI: 10.5061/dryad.4j0zpc8b9
title: High temperatures and human pressures interact to influence mortality in an African carnivore

description: The impacts of high ambient temperatures on mortality in humans and
 domestic animals are well understood. However, much less is known about
 how hot weather affects mortality in wild animals. High ambient
 temperatures have been associated with African wild dog Lycaon pictus pup
 mortality, suggesting that high temperatures might also be linked to high
 adult mortality. We analysed mortality patterns in African wild dogs
 radio-collared in Kenya (0°N), Botswana (20°S), and Zimbabwe (20°S), to
 examine whether ambient temperature was associated with adult mortality.
 We found that high ambient temperatures were associated with increased
 adult wild dog mortality at the Kenya site, and there was some evidence
 for temperature associations with mortality at the Botswana and Zimbabwe
 sites. At the Kenya study site, which had the highest human
 impact, high ambient temperatures were associated with increased risks of
 wild dogs being killed by people, and by domestic dog diseases. In
 contrast, temperature was not associated with the risk of snare-related
 mortality at the Zimbabwe site, which had the second-highest human impact.
 Causes of death varied markedly between sites. Pack size was
 positively associated with survival at all three sites. These
 findings suggest that while climate change may not lead to new causes of
 mortality, rising temperatures may exacerbate existing anthropogenic
 threats to this endangered species, with implications for conservation.
 This evidence suggests that temperature-related mortality, including
 interactions between temperature and other anthropogenic threats, should
 be investigated in a greater number of species to understand and mitigate
 the likely impacts of climate change.
description: Study sites We analysed adult African wild dog
 mortality at three sites: the Ewaso ecosystem, Kenya; the Okavango Delta,
 Botswana; and Savé Valley Conservancy, Zimbabwe. All three study sites
 fall within semi-arid savanna ecosystems.  Field Data Collection
 At the Kenya study site 130
 African wild dogs (56 female, 74 male) from 41 packs were monitored using
 either Vectronics GPS collars (GPS Plus, Vectronic Aerospace GmbH),
 Televilt GPS collars (GPS-Posrec, Televilt, Lindesberg, Sweden), Berlin,
 Germany), or VHF radio-collars (Telonics, Mesa AZ, USA). All three collar
 types included a mortality sensor programmed to emit a characteristic
 radio signal if stationary for ≥4h. At the Zimbabwe study site, 59 African
 wild dogs (22 female, 37 male) from 34 packs were monitored using either
 radio collars or GPS collars (African Wildlife Tracking, Rietondale,
 Pretoria, South Africa). Using radio-collars (Sirtrack, Havelock West, New
 Zealand) 31 African wild dogs (10 female, 21 male) from 16 packs were
 monitored at the Botswana site. Collars were fitted using the procedures
 outlined in McNutt (1996), Woodroffe (2011) and Jackson et al.
 (2017). At all
 three sites, packs were located every 1-2 weeks where possible. Any
 collared animal found dead was carefully examined with the aim of
 establishing a cause of death. At the Kenya site necropsies were carried
 out on all dead individuals located. At the Botswana site cause of death
 was only recorded in cases where the death was directly observed, or
 during disease outbreaks, and therefore the majority of causes of death
 were unconfirmed. Most deaths at the Botswana site are likely to be due to
 natural causes given the low human activity in this area. For all three
 sites, the date of first detection of a mortality signal from the collar
 was used to estimate the date of death when not observed directly, and
 where this was not possible an estimated date of mortality was made based
 on the date midway between the last sighting, or the last detection of the
 radio-collar without a mortality signal, and the discovery of the carcass
 or collar. If any study animal was not observed in its resident pack for
 over 30 days, no mortality signal was detected, and no carcass was found,
 it was considered lost from the study and censored from the day of the
 last observation (Kenya: n=51, Zimbabwe: n=34, Botswana: n=8). If a
 carcass or collar was discovered more than 30 days after the last sighting
 (n=2), the animal was considered lost from the study due to the inaccuracy
 of the date of death and was censored from the date of the last
 sighting. Group and
 individual characteristics were recorded at each site. At all three sites
 dispersal status of the individual was recorded. Individuals were defined
 as dispersing if they left their pack for multiple days and did not
 return, otherwise they were defined as resident (Woodroffe et al. 2019b).
 Group size – either the pack size for resident individuals or the
 dispersal group size for dispersing individuals – was recorded for each
 individual, and was defined as the number of adults (&gt;12 months in
 age) in the group. African wild dog pup-rearing involves the pups being
 left at a den site for the first three months of life while the majority
 of the rest of the pack hunt daily, bringing food back to provision the
 pups. This pup rearing period is referred to as denning. For each pack,
 denning periods were identified using either direct observations or
 GPS-collar data. At
 the Kenya site a number of other individual and pack characteristics were
 also monitored. Individuals’ alpha status was inferred based on consistent
 close association with a specific individual of the opposite sex,
 coordinated scent marking, and reproductive activity; all animals not
 identified as alpha were considered subdominant. African wild dog age was
 known for many individuals, otherwise it was estimated from tooth wear
 when the individual was collared (Woodroffe et al. 2019b). Age range at
 collaring ranged from 1 to 7 years old (mean: 2.43 ±1.27). The age of the
 majority of individuals at the Zimbabwe and Botswana sites was not
 known. Weather data
 is from weather stations within the field site at Mpala research station
 at the Kenya site (detailed in Caylor K., Gitonga, J. and Martins
 2016), 30km outside the study site at Maun airport for the Botswana site
 and the Middle Sabi Research Station, 12km from the study area boundary at
 the Zimbabwe research site. Data Processing
 The average mean temperature was taken on a 90 day rolling
 average at the Kenya and Zimbabwe sites, and a 30 day rolling average at
 the Botswana site. Rainfall was summed over a 30 day rolling time period
 at the Kenya and Botswana sites and a 90 day rolling period at the
 Zimbabwe site. 
description: Details of the column names can be found in the ReadMe
 file. There are three csvs, one for each study
 site. Missing values are indicated by an NA. In
 particular at the Kenya site there is a period in 2011 where the weather
 station was broken and therefore there is a period of missing data. There
 are also a number of time periods where variables such as age or dispersal
 status are unknown for particular dogs.