Search

Conflicts between human populations and Nile crocodiles are widespread with crocodiles posing significant threats to fisherfolk and riverine communities across r-Saharan Africa. Hundreds of deadly attacks take place annually, and mortality rates may range from 50% to 100%. Attitudes and perceptions towards crocodiles were studied using structured questionnaires among fisherfolk along the River Nile and the Sudd wetlands in South Sudan. Local communities used crocodiles for their meat and skin/leather trades. The meat is regarded to enhance longevity, sexual potency, and protection against witchcraft. Crocodiles are perceived as a main threat to lives and livelihoods as they restrict people's freedom of movement along water bodies, attack livestock and humans, and devastate fishing equipment. To assess whether responses were influenced by the intensity of crocodile threats, published data on fatal crocodile attacks on humans and livestock were analysed using Generalised Linear Models (GLMs). This analysis indicated a direct link between the number of crocodile attacks and human attitudes. Crocodiles were generally feared and hated, and there was the agreement of the need to destroy breeding habitats. However, some attitudes were complex and nuanced as highlighted by the agreement of local communities on the need to destroy Nile Crocodile breeding habitats on the one hand and the need to establish crocodile sanctuaries as the the preferred strategy to mitigate risks and conflict on the other hand. There is a need for the creation of a crocodile sanctuary in the Sudd wetlands to minimise the risks of illegal hunting and to buffer the increasing pressure on crocodiles due to human population growth and economic upturn after the civil war.

Organisms that are similar in size, morphological characteristics, and adaptations, including vertebrates, often coexist by partitioning the available resources (food, space, and time). So, studies of the dynamics of these cases of coexistence are scientifically interesting. Here, we study a coexistence case of two species of freshwater turtles inhabiting the forest waterbodies of West Africa, focusing on the dietary habits of the two species. We found that both turtle species are omnivorous generalists, eating both vegetal and animal matter abundantly. However, there were clear interspecific differences, with the larger of the two species ( P. cupulatta ) eating more vertebrates (mainly fish but occasionally other vertebrates), whereas P. castaneus consumed more invertebrates. These patterns appeared consistently within the species and across sites, highlighting that the same patterns were likely in other conspecific populations from the Upper Guinean forest streams (Côte d'Ivoire and Liberia). Our study also showed that interspecific competition for food does not occur between these two species; instead, previous studies uncovered that a clear partitioning of the habitat niche occurs. We conclude that the food resource is likely unlimited in the study areas, as it is not the case in more arid environments (since food shortages may occur during the dry season). We anticipate that, within the Pelomedusidae communities throughout Africa, intense competition for food probably occurs in the Sahel and Sudanian vegetation zones, particularly during the dry months, but is unlikely within the Guinea and wet savannah region and even less likely in the Guineo-Congolian rainforest region.

Biases in snake venom research have been partially identified but seldomly quantified. Using the Google Scholar web search engine, we collected a total of 267 articles published between 1964 and 2021, and reviewed them to assess the main trends in this field of study. We developed a 4-category classification of the harmful potential of each of the 298 snake species retrieved from the analysed publications, and tested whether taxonomy, realm of origin, and/or assigned hazard category could affect how often each of them appeared in the articles considered. Overall, viperids were significantly more represented than any other snake taxon retrieved. The Neotropics were the most represented biogeographic realm for number of studied species, whereas information about the country of origin of the analysed specimens was often incomplete. The vast majority of the publications focused on snake venom characterisation, whereas more ecology-related topics were rarely considered. Hazard category and biogeographic realm of origin of each species had a significant effect on the number of articles dedicated to it, suggesting that a snake's harmful potential and place of origin influence its popularity in venom studies. Our analysis showed an overall positive trend in the number of snake venom studies published yearly, but also underlined severe neglect of snake families of supposedly minor medical relevance (e.g., Atractaspididae), underrepresentation of some of the areas most impacted by snakebite (i.e., Indomalayan and Afrotropic realms), and limited interest in the ecological and functional context of snake venom.

"The Dahomey Gap" is a human-derived mostly savannah region that separates the Guineo-Congolian rainforest block into two major units: the Upper Guinean and the Lower Guinean Forest blocks. Several forest patches are distributed throughout this savannah-dominated habitat. The mammal communities in the Dahomey Gap region have been poorly studied. In this paper we analyse the species richness and abundance of, as well as conservation implications for, medium and large mammals (especially ungulates) inhabiting a complex of flooded forests near the Mono river in south-eastern Togo. We use several field methods to describe the species richness of mammals in this area, including camera-trapping, recce transects, Kilometric Index of Abundance (KIA) estimates, examination of hunters' catches and face-to-face hunter interviews. Overall, we directly recorded 19 species that coexist in these forests. Based on interviews, nine other species were confirmed as present in the study area. Only five species were common: Cephalophus rufilatus , Tragelaphus scriptus , Chlorocebus aethiops , Atilax paludinosus and Herpestes ichneumon . The area still contains various threatened species such as Tragelaphus spekii and Hippopotamus amphibius . We stress that to ensure the protection of the Dahomey Gap mammals, it is important to seriously consider protecting not only the forest patches but also the surroundings, mainly savannah landscapes.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

The Sudd in South Sudan, formed by the White Nile's Baḥr al-Jabal section, is one of the largest and most important wetlands in the world. Communities in the region almost exclusively depend on fisheries for food and livelihoods. Although threatened by over-exploitation and habitat changes, fish populations are also affected by climate change. Using semi-structured questionnaires, we assessed fisherfolk's opinions of how recent variation in climate affected their livelihoods and the environment. Fisherfolk perceived that climate had changed in the past decade and were negatively impacted by this. Interviewees reported average higher temperatures, a greater frequency of floods and droughts, unpredictable timing of seasons, and erratic rainfall. Destruction of fishing villages/camps, loss and damage of fishing equipment, shifts in the fishing calendar, reduction of fish trade, and fish catch declines as well as psycho-social problems were given as the major consequences of climate change. Causes of climate change and variability were perceived to be linked to uncontrolled harvest of forest resources, anger of God and ancestors, and natural variability in climate. Most respondents expressed a desire to adopt more responsible behavior such as planting trees and establishing community nurseries, being educated on climate change risks, and sustainable fisheries management. Our results show that fisherfolk in the Sudd are troubled by climate change impacts on their livelihoods and on fish populations. In South Sudan, climate change has been reported from hydroclimatological data but concrete impacts on people remain largely unknown and of little concern because of recent wars and the poor economy. Our study provides an example of how fisherfolks' local ecological knowledge (LEK) can be used as an early warning system of the negative impacts on livelihoods and fish populations and support adaptation to the changing climate., Supplementary Information: The online version contains supplementary material available at 10.1007/s10113-022-01928-w., Competing Interests: Conflict of interestThe authors declare no competing interests., (© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022.)

As a result of sedentarisation many Baka Pygmies have changed their mobility patterns away from nomadic lifestyles to living in roadside villages. These settled groups are increasingly dependent on cultivated foods but still rely on forest resources. The level of dependence on hunting of wild animals for food and cash, as well as the hunting profiles of sedentarised Pygmy groups is little known. In this study we describe the use of wild meat in 10 Baka villages along the Djoum-Mintom road in southeastern Cameroon. From data collected from 1,946 hunting trips by 121 hunters, we show that most trips are of around 13 hours and a median of eight hours. A mean ± SD of 1.15 ± 1.11 animal carcasses are taken in a single trip; there was a positive correlation between duration of trips and carcasses. A total of 2,245 carcasses of 49 species of 24 animal families were taken in the study; species diversity was similar in all villages except one. Most hunted animals were mammals, with ungulates contributing the highest proportion. By species, just over half of the animal biomass extracted by all hunters in the studied villages was provided by four mammal species. Most animals were trapped (65.77% ± 16.63), followed by shot with guns (22.56% ± 17.72), other methods (8.69% ± 6.96) and with dogs (2.96% ± 4.49). A mean of 7,569.7 ± 6,103.4 kg yr -1 (2,080.8-19,351.4) were extracted per village, giving 75,697 kg yr -1 in total, which is equivalent to 123 UK dairy cattle. In all villages, 48.07% ± 17.58 of animals hunted were consumed by the hunter and his family, around 32.73% ± 12.55, were sold, followed by a lower percentage of carcasses partially sold and consumed (19.21% ± 17.02). Between 60% and 80% of carcasses belonged to the "least concern" category, followed by "near threatened", "vulnerable" and, rarely "endangered". The only endangered species hunted was the chimpanzee ( Pan troglodytes ). We suggest that hunting is a critical activity that provides a vital source of food for our study communities. Measured wild meat extraction levels are likely to be sustainable if hunter densities do not increase., Competing Interests: Eva Avila Martin, Guillermo Ros Brull, and Robert Okale are employed by Zerca y Lejos ONGD. Stephan M. Funk is employed by Nature Heritage. Luca Luiselli is employed by Institute for Development, Ecology, Conservation and Cooperation., (©2020 Avila Martin et al.)

Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of the 360 living species and 482 total taxa (species and subspecies combined) are threatened with extinction. This places chelonians among the groups with the highest extinction risk of any sizeable vertebrate group. Turtle populations are declining rapidly due to habitat loss, consumption by humans for food and traditional medicines and collection for the international pet trade. Many taxa could become extinct in this century. Here, we examine survival threats to turtles and tortoises and discuss the interventions that will be needed to prevent widespread extinction in this group in coming decades., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Foraging modes (ambush vs. active foraging) are often correlated with a suite of morphological, physiological, behavioural and ecological traits known as the "adaptive syndrome" or "syndrome hypothesis." In snakes, an ecological correlate often reported in the literature is that ambush-hunting snakes have a higher relative meal size compared to actively foraging snakes which feed on smaller prey items. This "large meal versus small meal" feeding hypothesis between ambush and active foragers has become a widely accepted paradigm of snake feeding ecology, despite the fact that no rigorous meta-analysis has been conducted to support this generalization. We conducted a phylogenetically explicit meta-analysis, which included ca. 100 species, to test this paradigm of snake feeding ecology. We gathered data on prey size by inducing regurgitation by palpation in free-ranging snakes and by examining the stomach contents of preserved museum specimens. When we found prey, we recorded both snake and prey mass to estimate relative prey mass (prey mass/snake mass). We also reviewed published studies of snake feeding ecology to gather similar information for other species. Ambush and active foragers did not differ in minimum or average meal size but the maximum meal sizes consumed by ambush-foraging snakes were larger than the maximum meal sizes eaten by active foragers. This results in ambush-foraging snakes consuming a significantly wider range of meal sizes, rather than being large meal specialists compared to active foragers. We argue that ambush foragers evolved to be more opportunistic predators because they encounter prey less frequently compared to active foragers. This hypothesis is further supported by the fact that ambush foragers also exhibited marginally wider diet breadths, consuming a broader range of prey types in comparison with active foragers. Our study challenges aspects of the foraging syndrome as it is currently conceived, and our results have important implications for our understanding of how foraging mode has shaped the behaviour and physiology of ambush-foraging snakes., (© 2019 The Authors. Journal of Animal Ecology © 2019 British Ecological Society.)

The interaction of anthropogenic litter (by incorporation litter in nests, ingestion, and entanglement) with birds was systematically reviewed using Google Scholar database. A 'black-list' of 258 species was compiled. Among them 206 (79.8%) were seabirds. Four seabird orders (Gaviiformes, Phaetontiformes, Procellariformes, Sphenisciformes) showed the highest percentage of interacting species. At family level, >70% of species of Gaviidae, Diomedeidae, Sulidae, Stercoraridae and Alcidae were involved in interactions with litter. We observed (i) a significant correlation between Scholar recurrences and species citations about anthropogenic litter only when considering seabirds; (ii) a low number of references before 1981 with a bimodal pattern showing a first peak in 1986-90 and a progressively increasing trend in the 2000s. Regarding the type of interaction, there was a significantly higher percentage of species involved in ingestion when compared to the percentage involved in entanglement. We suggest the use of consolidated standardized litter nomenclature and characterization and the adoption of a logical causal chain helping researchers in defining suitable frameworks., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Monospecific and bispecific genera are of special concern as they represent unique phylogenetic/evolutionary trajectories within larger clades. In addition, as phylogenetically older taxa are supposed to be exposed to higher rarity and extinction risk, monospecific and bispecific genera may be intrinsically more prone to extinction risks than multispecies genera, although extinction risks also depend on the ecological and biological strategy of the species. Here, the distribution across biogeographical zones and the levels of threat to 2 speciose orders of mammals (monospecific and bispecific genera of Rodentia and Soricomorpha) are investigated in order to highlight major patterns at the worldwide scale. In Rodentia, 39.7% of the genera (n = 490) were monospecific and 17.9% were bispecific. In Soricomorpha, 44.4% of the total genera (n = 45) were monospecific and 15% were bispecific. There was a positive correlation between the number of monospecific genera and the total number of genera per family. Peaks of monospecific and bispecific genera richness were observed in Neotropical, Oriental and Afrotropical regions in rodents and in the Palearctic region in soricomorphs. Range size was significantly uneven across biogeographic region in rodents (with larger ranges in Nearctic and Oriental regions and smaller ranges in the Australian region), but there was no difference across biogeographic regions in terms of range size in soricomorphs. Most of the monospecific and bispecific genera occurred in forest habitat in both taxa. The frequency distribution of the monospecific and bispecific genera across IUCN categories did not differ significantly from the expected pattern using the total rodent genera and the multispecies genera., (© 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

Recent molecular evidence suggests that Sciurus vulgaris populations from Calabria (southern Italy) are distinct from those occurring in northern and central Italy. Here, we re-analyzed using multivariate and univariate techniques an historical dataset provided by Cavazza (1913), who documented measurements for the now extinct squirrel population from Campania. Both univariate and multivariate analyses confirmed that the sample from Calabria was homogenous and relatively distinct compared to the rest of the squirrel samples.

Terrestrial tortoises are the most endangered group of vertebrates but they are still largely ignored for defining global conservation priorities. In this paper, we explored within a hierarchical framework the potential contribution of prioritization studies at the continental scale to the planning of local initiatives for the conservation of African tortoises at the regional level. First, we modeled the distribution of all the African tortoise species, we calculated three indicators of conservation priority (i.e., species richness, conservation value, and complementarity), and we carried out a gap analysis at continental scale. Second, we focused on the most important region for tortoise conservation and performed the same analyses at higher resolution. Finally, we compared the results from the two scales for understanding the degree to which they are complementary. Southern Africa emerged from the continental analysis as the most important region for tortoises. Within this area, the high-resolution analysis pointed out specific core sites for conservation. The relative degree of species protection was assessed similarly at the two different resolutions. Two species appeared particularly vulnerable at both scales. Priority indices calculated at high resolution were correlated to the values calculated for the corresponding cells at low resolution but the congruence was stronger for species richness. Our results suggest to integrate the calculation of conservation value and complementarity into a hierarchical framework driven by species richness. The advantages of large scale planning include its broad perspective on complementarity and the capability to identify regions with greatest conservation potential. In this light, continental analyses allow targeting fine scale studies toward regions with maximum priority. The regional analyses at fine scale allow planning conservation measure at a resolution similar to that required for the practical implementation, reducing the uncertainty associated with low resolution studies.

Background: Venomous snakes are among the most serious health hazards for rural people in tropical regions of the world. Herein we compare the monthly activity patterns of eight venomous snake species (Elapidae and Viperidae) with those of rural people in the Niger Delta area of southern Nigeria, in order to identify the periods of highest potential risk for persons, and the human group actually at greater risk of snakebite., Results: We documented that above-ground activity of all venomous snakes peaked in the wet season, and that high snake activity and high human activity were most highly correlated between April and August. In addition, we documented that women and teenagers were at relatively higher risk of encountering a venomous snake than adult males, despite they are less often in the field than men., Conclusions: Our results suggest that future programs devoted to mitigate the social and health effects of snakebites in the Niger Delta region should involve especially women and teenagers, with ad-hoc education projects if appropriate. We urge that international organizations working on social and health problems in the developing world, such as IRD, DFID, UNDP, should provide advice through specific programs targeted at especially these categories which have been highlighted in comparatively potential higher threat from snakebites than adult men.

Twenty-eight fish muscle specimens from the main water bodies of the Campania Region were analyzed in our laboratory. On average, results showed a low contamination by PCDDs+PCDFs and a relatively more important presence of DL-PCBs. All specimens were compliant with EU regulatory maximum levels. Cumulative PCDD+PCDF+DL-PCB concentrations (TEQ(TOT)) were comprised in the range 0.223-11.4 pgWHO(97)-TEQ g(-1) fresh weight (fw). DL-PCB contribution to TEQ(TOT) was on average greater than 86% (range, 50.2-97.1%). The cumulative concentrations of 30 non-dioxin-like PCB congeners (Σ(30)(NDL-PCBs)) and of the six indicators (Σ(6)(NDL-PCBs)) were respectively in the ranges 3.30-515 and 1.30-195 ng g(-1) fw. The hybrid clustering approach adopted to analyze the sample-specific congener profiles indentified the main analytical patterns present in the database and, in particular, two main diverse exposure macro-areas that seem to exist north and south of the city of Naples. The distribution of PCDD and PCDF congeners among different species showed significant variations from chub (Leuciscus cephalus), characterized by a higher proportion of low-chlorinated congeners (e.g. 2,3,7,8-T(4)CDD), to eel (Anguilla anguilla), whose contamination consisted mainly of highly chlorinated congeners (e.g. O(8)CDD). To have a more complete perspective in relation to the contaminants present in the environment, the study suggestion is to use benthic as well as pelagic species to obtain an integrated characterization of fish tissue contamination., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Anuran amphibians have traditionally been considered suitable model organisms for community ecology studies. In this paper, we review and quantitatively re-analyze the original studies published on dietary relationships among anuran communities worldwide. We re-analyzed 33 independent communities from all continents, including data on prey numbers and/or prey volumes. All datasets underwent null model re-analysis using two randomization algorithms. In addition, logistic regression models were used to identify specific assemblage patterns. We discovered three main patterns: (1) one particular algorithm (RA2, which replaces every cell in the matrix with one randomly chosen, but retains the zero structure of the matrix) performed much better at uncovering community structure; (2) nonrandom structure was more likely to occur in tropical than in nontropical regions; (3) prey volume was a better descriptor of dietary relationships than prey number when attempting to detect nonrandom structure. We showed that: pattern (1) depended on both the overall generalist nature of the anurans in general and on the mathematical properties of RA2; pattern (2) was consistent with theoretical attributes of tropicality; and pattern (3) was due to the intrinsic ecological properties of generalist organisms, which forage more or less opportunistically on prey of very different sizes; hence, when prey number is used as a diet descriptor, there is a risk of approximating different prey taxa that make different relative volume contributions to the overall diet as being of similar relevance .

Climate change modelers predict increasingly frequent "extreme events," so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of mal" (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.

Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined sharply over the same relatively short period of time with five remaining stable and one showing signs of a marginal increase. Although the causes of these declines are currently unknown, we suspect that they are multi-faceted (such as habitat quality deterioration, prey availability), and with a common cause, e.g. global climate change, at their root.

A 5-year mark-recapture study of smooth snakes (Coronella austriaca) in the Carnic Alps (1100 m above sea level) of north-eastern Italy provided extensive information on the biology and life-history of these small viviparous snakes. Offspring were relatively large (mean=15 cm total length, 2.9 g) when they were born in late summer, and females grew to maturity (44 cm, 50 g) in approximately 4 years. Larger neonates retained their size advantage for at least 12 months, but did not have a higher probability of survival. Although sexual size dimorphism (at birth and at mean adult body sizes) was minor, the sexes differed significantly in several respects. Females grew faster than males during juvenile life, and adult females diverged in dietary habits from the rest of the population. Whereas juveniles (of both sexes) and adult males fed primarily on lizards, larger females shifted to feeding less frequently, but taking larger prey (mammals and snakes). Reproductive output increased strongly with maternal body size: larger females reproduced more frequently, produced larger litters of larger neonates, had higher relative clutch masses (RCMs), and had a lower proportion of stillborn off-spring. Most females produced a litter every 2nd or 3rd year. We did not detect significant year-to-year variation in reproductive traits over the 5 years of our study. Females were consistent from one litter to the next in several traits (e.g., litter sizes, offspring sizes and shapes, proportions of stillborn neonates, RCMs), but this consistency was due to differences in body size among females rather than to size-independent maternal effects. Overall litter sex ratios averaged 50/50, but sex ratios tended to be more male-biased in litters that were unusually large relative to maternal body size, and in litters containing a high proportion of stillborn offspring. "Costs" of reproduction appear to be high in this population, in terms of both energy allocation and risk. Reproduction reduced growth rates, and females that recovered condition more quickly in the year after reproduction were able to reproduce again after a briefer delay. Mortality was highest in reproducing females with high RCMs, and in females that were very emaciated after parturition. The marked increase in reproductive output with increasing maternal body size in C. austriaca may reflect a reduction in "costs" as females grow larger, and the dietary shift to larger prey may enhance the rate that females can accumulate energy for reproduction.