Triiodothyronine (T3) levels fluctuate in response to ambient temperature rather than nutritional status in a wild tropical ungulate

Animals can employ a range of physiological mechanisms in response to unpredictable changes within their environment, such as changes in food availability and human disturbances. For example, impala exhibit higher faecal glucocorticoid metabolite (FGM) levels—indicative of physiological stress—in response to low food quality and higher human disturbance. In this study, we measured faecal triiodothyronine (T3) metabolite (FTM) levels in 446 wild impala from 2016 to 2018 to test the hypothesis that environmental and human disturbances would affect their physiological status. We also validated a faecal thyroid hormone assay. T3 levels mainly regulate metabolic rate and drive thermoregulation—increasing with colder temperatures. We predicted that individuals would have lower FTM levels, indicative of poor physiological status, (i) when food quality was poor, (ii) when ambient temperature (Ta) was high, (iii) in areas of high human disturbance (due to food competition with livestock) and (iv) when FGM levels were high. Interestingly, we found that Ta was the most important predictor of FTM—FTM levels decreased by 70% from lowest to highest Ta—and food quality and human disturbance only influenced FTM levels when Ta was accounted for. FTM levels also tended to increase with increasing FGM levels, opposite our predictions. Our results suggest that food quality and availabilitymay only partially influence FTM levels and that fluctuations in Ta are a significant driver of FTM levels in a wild tropical ungulate. Given that thyroid hormones are primarily responsible for regulating metabolic rate, they may be better indicators of how wild animals metabolically and energetically respond to environmental factors and only indicate poor nutritional status in extreme cases. glucocorticoid, impala, Serengeti, stress, thyroid hormones, validationpublishedVersio

Physiological and behavioral adaptations of impala to anthropogenic disturbances in the Serengeti ecosystems

Anthropogenic activities are causing biodiversity loss at an unprecedented rate and attempts to ameliorate our impacts have largely failed. This thesis aimed to contribute to our understanding of how anthropogenic activities affect wildlife populations, using physiological and behavioural indices as a window into the status of a wild ungulate population. We used various remotely-sensed proxies of both direct human disturbance (i.e. land use area, settlement density, and distance from a pro- tected area) and environmental conditions (i.e. forage quality, temperature, and rainfall) to test how these disturbances affected the physiological state (i.e. glucocorticoid and thyroid hormone concentrations), behaviour, and demography of impala populations in the Serengeti ecosystem, Tanzania. We found that impala showed significant variation in hormone concentrations in response to both direct human disturbances and changes in environmental conditions. However, hormone concentrations were much more strongly affected by variation in the environment, such as forage quality and temperature, than by direct human disturbances. Impala populations in land use areas which allow more exploitation showed behavioural and demographical changes that could lower population persistence. These results suggest that, although human activities do have a significant impact, with climate change becoming increasingly pervasive, climate and land use change are likely to be the biggest long-term threats to impala populations in the Serengeti ecosystem. Therefore, we suggest that managers focus on conserving larger natural systems, well beyond the boundaries of few strictly protected areas. Additionally, this thesis shows the advantages of combining both behavioural, physiological, and remote-sensing methods to obtain a more complete picture of the threats facing wildlife populations, disentangling their responses to disturbances, and the fitness implications of those responses. However, one should always consider the physiological, ecological, and evolutionary context of the biological methods used to inform conservation research. It is my hope that future work will recognise this complexity and design studies and interpret results with this in mind

The influence of human induced factors on African elephant (Loxodonta africana) populations in Sub-Saharan Africa

Numerous studies have been done on the conservation of the African elephant (Loxodonta africana) yet too few studies have focused on comparing the ultimate factors that influence the African elephant populations. Here, we looked at several human induced factors that reflect parts of the Human Elephant conflict and tried to find which one of those had the most important effect on African elephant populations in Sub-Saharan countries. Agricultural activity and deforestation together with increasing human population density and poaching all have a negative effect on elephant populations. However, we found that poverty, measured by per capita income, was by far the most significant factor affecting elephant populations. This variable translates in not only individual poverty that results in lucrative poaching, but also in national economical and political stability, which is essential for effective conservation management. Furthermore, our results show that, in order to protect the African elephant, tackling the poverty problem is more important than creating new protected areas

Being stressed outside the park — conservation of African elephants (Loxodonta africana) in Namibia

The conservation of the African savanna elephant (Loxodonta africana) is of prime importance for many African countries. Interactions between elephants and humans are known to induce stress and thereby have the potential to affect elephants’fitness. In Namibia, anthropogenic disturbances are increasing due to increasing human population size and development, particularly near protected areas, such as national parks. In this study, we investigated elephant stress levels in relation to their land use, specifically their protection status, comparing elephants within Etosha National Park in Namibia with elephants residing outside the park. We noninvasively collected dung samples of 91 elephants and determined the concentration of faecal glucocorticoid metabolites (fGCM), an indicator of physiological stress. Elephants outside the park (N = 35) had significantly higher concentrations of fGCM than those inside ENP (N = 56), suggesting that, despite including community-based conservancies, unprotected areas are more stressful for elephants than protected areas, most likely due to increased interactions with humans. We also found that males had lower fGCM concentrations than females, but no significant effect of age, body size or group size was detected. Additionally, herd sizes were significantly smaller and calf recruitment was potentially lower in unprotected areas. These findings underpin the importance of protected areas such as ENP, while encouraging decision-makers to continue reducing and mitigating potential human-induced disturbances.publishedVersio

Gastric ulcer in a child treated with deferasirox

We present a patient with thalassemia major who developed a gastric ulcer, probably related to the use of deferasirox. Although gastric ulcer is mentioned as infrequent adverse event in the scientific product information of deferasirox, in our current knowledge, this is the first case-report on this adverse drug reaction. The severity of this event justifies the reporting of this case

Behavioural and demographic changes in impala populations after 15 years of improved conservation management

Many protected areas (PAs) have been created globally in response to the dramatic human- induced decline in biodiversity. However, not all PAs successfully preserve their biodiversity and continued monitoring is vital to assess the effectiveness of conservation efforts. Here, we repeated a study done in 2003 to assess whether investments in anti-poaching in two par-tially PAs (PPAs), Grumeti Game Reserve (GGR) and Ikona Wildlife Management Area (IWMA), have had quantifiable impacts on impala (Aepyceros melampus) populations, com-pared to the adjacent strictly protected Serengeti National Park. Since 2003, management of the PPAs has changed dramatically under the non-profit organisation Grumeti Fund. We predicted that if conservation management had improved, impala populations in 2018 would have higher local density, less female-skewed sex ratio, larger group sizes, and shorter flight initiation distances (FID). To assess these parameters of the impala populations, we con-ducted the same road-based surveys in 2003 and 2018. We found that compared to 2003, impala population density doubled in GGR, group sizes were larger in IWMA and nearly doubled in GGR, and that impala had shorter FID in IWMA in 2018. Our results suggest that the changes in conservation management could have led to the observed positive impacts for impala populations. Our study is encouraging for managers and reveals a conservation success story: if proper action is taken to increase the protection of wildlife within PPAs, wildlife populations may respond quickly and positively.publishedVersio

The impacts of human disturbances on the behaviour and population structure of impala (Aepyceros melampus) in the Serengeti ecosystem, Tanzania

Human activities can lead to various changes in wildlife populations’ behaviour and dynamics. Understanding specific responses to disturbances can help conservation management better protect wildlife populations to coexist with local communities. Here, we studied the response of a model ungulate species, the impala (Aepyceros melampus), to different types of human activities in the Serengeti ecosystem. Impala were studied in central Serengeti National Park (CSNP), an area with relatively low human disturbance, and, with increasing levels of human disturbance, in western Serengeti National Park (WSNP), Grumeti Game Reserve (GGR), Ikona Wildlife Management Area (IWMA), and Loliondo Game Controlled Area (LGCA); pastoralism and/or hunting are the main disturbances in these areas. We hypothesised that in the exploited GGR, IWMA and LGCA areas, 1) impala would spend more time on costly behaviours, 2) sex ratios would be more female skewed, and 3) group sizes, reproduction and recruitment ratios would be lower compared to CSNP. We found that impala spent less time resting in IWMA and LGCA, as well as a significantly lower proportion of males, and lower reproduction and recruitment ratios in LGCA. Impala synchronized their behaviour, increasing their social cohesion potentially resulting in more efficient anti-predator strategies. Human activities induced a behavioural response in impala, indicating that in less regulated areas where pastoralism and hunting are allowed, these disturbances can potentially affect impala population persistence. These results highlight the importance of protected areas for wildlife populations, and the need for continuous monitoring of the impala and other ungulate populations in less regulated areas, as the underlying anthropogenic disturbances are likely impacting diverse species.publishedVersion© 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )