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Wildfact Library
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Comparative Distribution and Habitat Use by Antelope and Mule Deer
Abstract Aerial surveys were used to determine habitat use and distribution of sympatric pronghorn antelope ([i]Antilocapra americana[/i]) and mule deer ([i]Odocoileus hemionus[/i]) populations in eastern Montana from 1982 to 1987. Antelope seasonally occupied only 1–10%, and deer only 9–20%, of the study area. Grassland habitats were used most frequently by antelope; badlands, bunchgrass prairies, and hardwood draws were used most frequently by deer. Some overlap in habitat use was evident but there was little spatial overlap. Maximum overlap in both habitat use and distribution occurred during autumn when antelope moved into deer habitat. There appeared to be little opportunity for interspecific competition during this study based on the high degree of spatial segregation.
Predation risk constrains herbivores’ adaptive capacity to warming
Abstract Global warming compels larger endothermic animals to adapt either physiologically or behaviourally to avoid thermal stress, especially in tropical ecosystems. Their adaptive responses may however be compromised by other constraints, such as predation risk or starvation. Using an exceptional camera-trap dataset spanning 32 protected areas across southern Africa, we find that intermediate-sized herbivores (100–550 kg) switch activity to hotter times of the day when exposed to predation by lions. These herbivores face a tight window for foraging activity being exposed to nocturnal predation and to heat during the day, suggesting a trade-off between predation risk and thermoregulation mediated by body size. These findings stress the importance of incorporating trophic interactions into climate change predictions.
Species better track climate warming in the oceans than on land
Abstract There is mounting evidence of species redistribution as climate warms. Yet, our knowledge of the coupling between species range shifts and isotherm shifts remains limited. Here, we introduce BioShifts—a global geo-database of 30,534 range shifts. Despite a spatial imbalance towards the most developed regions of the Northern Hemisphere and a taxonomic bias towards the most charismatic animals and plants of the planet, data show that marine species are better at tracking isotherm shifts, and move towards the pole six times faster than terrestrial species. More specifically, we find that marine species closely track shifting isotherms in warm and relatively undisturbed waters (for example, the Central Pacific Basin) or in cold waters subject to high human pressures (for example, the North Sea). On land, human activities impede the capacity of terrestrial species to track isotherm shifts in latitude, with some species shifting in the opposite direction to isotherms. Along elevational gradients, species follow the direction of isotherm shifts but at a pace that is much slower than expected, especially in areas with warm climates. Our results suggest that terrestrial species are lagging behind shifting isotherms more than marine species, which is probably related to the interplay between the wider thermal safety margin of terrestrial versus marine species and the more constrained physical environment for dispersal in terrestrial versus marine habitats.
Thresholds of mangrove survival under rapid sea level rise
Abstract The response of mangroves to high rates of relative sea level rise (RSLR) is poorly understood. We explore the limits of mangrove vertical accretion to sustained periods of RSLR in the final stages of deglaciation. The timing of initiation and rate of mangrove vertical accretion were compared with independently modeled rates of RSLR for 78 locations. Mangrove forests expanded between 9800 and 7500 years ago, vertically accreting thick sequences of organic sediments at a rate principally driven by the rate of RSLR, representing an important carbon sink. We found it very likely (>90% probability) that mangroves were unable to initiate sustained accretion when RSLR rates exceeded 6.1 millimeters per year. This threshold is likely to be surpassed on tropical coastlines within 30 years under high-emissions scenarios.
Anthropogenic Disturbance and Population Viability of Woodland Caribou in Ontario
ABSTRACT One of the most challenging tasks in wildlife conservation and management is to clarify how spatial variation in land cover due to anthropogenic disturbance influences wildlife demography and long‐term viability. To evaluate this, we compared rates of survival and population growth by woodland caribou (Rangifer tarandus caribou ) from 2 study sites in northern Ontario, Canada that differed in the degree of anthropogenic disturbance because of commercial logging and road development, resulting in differences in predation risk due to gray wolves (Canis lupus ). We used an individual‐based model for population viability analysis (PVA) that incorporated adaptive patterns of caribou movement in relation to predation risk and food availability to predict stochastic variation in rates of caribou survival. Field estimates of annual survival rates for adult female caribou in the unlogged (  *This image is copyright of its original author 0.90) and logged ( *This image is copyright of its original author 0.76) study sites recorded during 2010–2014 did not differ significantly (P > 0.05) from values predicted by the individual‐based PVA model (unlogged:  *This image is copyright of its original author = 0.87; logged:  *This image is copyright of its original author 0.79). Outcomes from the individual‐based PVA model and a simpler stage‐structured matrix model suggest that substantial differences in adult survival largely due to wolf predation are likely to lead to long‐term decline of woodland caribou in the commercially logged landscape, whereas the unlogged landscape should be considerably more capable of sustaining caribou. Estimates of population growth rates (λ ) for the 2010–2014 period differed little between the matrix model and the individual‐based PVA model for the unlogged (matrix model  *This image is copyright of its original author = 1.01; individual‐based model  *This image is copyright of its original author = 0.98) and logged landscape (matrix model  *This image is copyright of its original author = 0.88; individual‐based model  *This image is copyright of its original author = 0.89). We applied the spatially explicit PVA model to assess the viability of woodland caribou across 14 woodland caribou ranges in Ontario. Outcomes of these simulations suggest that woodland caribou ranges that have experienced significant levels of commercial forestry activities in the past had annual growth rates <0.89, whereas caribou ranges that had not experienced commercial forestry operations had population growth rates >0.96. These differences were strongly related to regional variation in wolf densities. Our results suggest that increased wolf predation risk due to anthropogenic disturbance is of sufficient magnitude to cause appreciable risk of population decline in woodland caribou in Ontario. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.
Inconsistent detection of extinction debts using different methods
Abstract: The extinction debt, delayed species extinctions following landscape degradation, is a widely discussed concept. But a consensus about the prevalence of extinctions debts is hindered by a multiplicity of methods and a lack of comparisons among habitats. We applied three contrasting species–area relationship methods to test for plant community extinction debts in three habitats which had different degradation histories over the last century: calcareous grassland, heathland and woodland. These methods differ in their data requirements, with the first two using information on past and current habitat area alongside current species richness, whilst the last method also requires data on past species richness. The most data‐intensive, and hence arguably most reliable method, identified extinction debts across all habitats for specialist species, whilst the other methods did not. All methods detected an extinction debt in calcareous grassland, which had undergone the most severe degradation. We conclude that some methods failed to detect an extinction debt, particularly in habitats that have undergone moderate degradation. Data on past species numbers are required for the most reliable method; as such data are rare, extinction debts may be under‐reported.
Carnivoran postcranial adaptations and their relationships to climate
Abstract: The relationship between climate and morphology is important to understand in view of the rapid rate of climate change occurring today; however, this relationship has not been fully explored in many mammalian groups. We use postcranial indices to explore the association between climate and morphology in the mammalian order Carnivora. Carnivora is a good group to use for this analysis because it includes species with a variety of locomotor ecologies that live in almost every type of habitat on Earth. We measured postcrania of 121 carnivoran species from around the world, combined with habitat and climate data from the BIOCLIM database and the NCEAS Paleocommunities Working Group to examine correlations between postcrania, temperature and precipitation. We analyzed these data using correspondence analysis and multiple linear regressions. We found three postcranial indices that were significantly correlated with climate. Brachial index (radius/humerus) and shoulder moment (length deltopectoral crest/length humerus) were both significantly associated with temperature and precipitation, while greater trochanter height (as proportion of femur length) was associated with precipitation. We found that these indices were indirectly related to climate via the strong association between climate and locomotor ecologies. This relationship between climate and postcranial proportions can be used in future studies: for paleo‐climate reconstruction in carnivore localities and for trait‐based identification of species vulnerability as climate change continues.
Of the world’s three largest tropical rainforests, the Congo river basin is the only remaining strong net carbon sink. SE Asia has already become a source. Amazon river basin teeters on the edge.
https://wri.org/blog/2021/01/forests-carbon-emissions-sink-flux  *This image is copyright of its original author
Historical and current distribution ranges and loss of mega-herbivores and carnivores of Asia
Abstract: Ecosystem functioning is dependent a lot on large mammals, which are, however, vulnerable and facing extinction risks due to human impacts mainly. Megafauna of Asia has been declining for a long, not only in numbers but also in their distribution ranges. In the current study, we collected information on past and current occurrence and distribution records of Asia’s megafauna species. We reconstructed the historical distribution ranges of the six herbivores and four carnivores for comparison with their present ranges, to quantify spatially explicit levels of mega-defaunation. Results revealed that historically the selected megafauna species were more widely distributed than at current. Severe range contraction was observed for the Asiatic lion, three rhino species, Asian elephant, tigers, and tapirs. Defaunation maps generated have revealed the vanishing of megafauna from parts of the East, Southeast, and Southwest Asia, even some protected Areas losing up to eight out of ten megafaunal species. These defaunation maps can help develop future conservation policies, to save the remaining distribution ranges of large mammals.
It's clear to see why this amazing paper won the Journal of Zoology 2019 paper of the year. We tend to underestimate non mammalian/bird intelligence in the animal world, which is interesting since birds are actually reptiles. Things like this shouldn't be so unexpected really.
Learning skills in Tropidurus lizards are associated with territory harshness Abstract Learning increases the ability to cope with challenges experienced in natural environments and likely affects animal survival, especially in harsh environments. Most evidence for associations between environmental characteristics and learning ability derives from comparisons among closely related species of mammals or birds, although the contribution of such behavioral trait for variation in habitat usage may be established among individuals at the population level. Here, we used individuals of Tropidurus catalanensis lizards from the same population to test for associations between individual problem-solving capacity and the type of territory used. Our prediction was that individuals living in harsher territories would exhibit enhanced capability for problem solving than lizards from more permissive (mild) territories. Lizards were tested during eight non-consecutive days using a customized feeder and visual cues. After confirming that lizards learn to solve the proposed task, we corroborated the hypothesis that environmental parameters affecting territory harshness are associated with individual learning capacity. Specifically, individuals living in harsh territories presented greater enhancement of their performance for problem solving with exposure to the task. We also identified that some of these lizards shifted their behavior along the 2 weeks of trials, adopting an approach that apparently minimized attempts prior to success. Challenges imposed by structurally different territories may be overcome by individuals exhibiting enhanced learning, a skill that may initially allow colonization of harsh territories by a given set of individuals but might also be cryptic in the population and then become expressed in response to specific environmental settings.
Factors affecting the spatial distribution and co-occurrence
of two sympatric mountain ungulates in southern Mongolia Abstract Co-occurrence of ungulates in multi-species assemblages has fascinated ecologists because these species seemingly belong to the same guild – feeding on plants. Across large parts of the high mountains of Central Asia, ibex (Capra sibirica) and argali (Ovis ammon), both predominantly grazers, co-occur at local and regio- nal scales. However, little is known about the ecological and anthropogenic factors that inuence their spatial distribution, co-occurrence and habitat use. We examined factors affecting the distribution and co-occurrence of these two sympatric species in Tost Tosonbumba Nature Reserve in southern Mongolia using an occupancy modeling approach. Specically, we used single species occupancy models to examine the inuence of road density, livestock density, terrain ruggedness and ele- vation on occupancy of these two species separately. We then assessed how these two species inuence each other’s distribution by using multi-species occupancy models. The model-averaged occupancy probabilities for ibex and argali were 0.64 0.3 SE and 0.44 0.2 SE, respectively. Terrain ruggedness positively inu- enced ibex distribution, while it negatively affected the occupancy of argali. We found limited evidence of relationship with factors associated with human distur- bance. The species interaction factor, which indicates the level of co-occurrence, suggested that ibex and argali occurred independent of each other (φ =- 0.72 0.3 SE). Together, our results imply that there was limited co-occurrence between the two species and that this was largely driven by terrain ruggedness at the scale of the home range. These results suggest that topography plays an impor- tant role in enabling these two species to co-occur at the regional scale.
Really interesting paper here
Temperatures that sterilize males better match global species distributions than lethal temperatures Abstract Attempts to link physiological thermal tolerance to global species distributions have relied on lethal temperature limits, yet many organisms lose fertility at sublethal temperatures. Here we show that, across 43 Drosophila species, global distributions better match male-sterilizing temperatures than lethal temperatures. This suggests that species distributions may be determined by thermal limits to reproduction, not survival, meaning we may be underestimating the impacts of climate change for many organisms.
[b]How many sabertooths? Reevaluating the number of carnivoran sabertooth lineages with total-evidence Bayesian techniques and a novel origin of the Miocene Nimravidae[/b]
ABSTRACT Sabertooth craniodental adaptations have evolved numerous times amongst carnivorous mammals. Some of the most extreme sabertooth adaptations are found within the carnivoran subfamily Barbourofelinae. However, the evolutionary origins of this group have been uncertain for more than 170 years, with variable placement as an independent case of sabertooth acquisition, as a clade within the Nimravidae (Eocene to Oligocene ‘false sabertooth cats’), or as a member of the Machairodontinae (true sabertooth cats such as Smilodon). Here we present a novel approach to assessing the validity of three independent sabertooth clades within Carnivora. We performed a total-evidence Bayesian analysis in Beast2 across all major carnivoran families, using the fossilized birth-death (FBD) model and incorporating 223 morphological characters, nuclear and mitochondrial gene sequences, and stratigraphic occurrence data. Our results place barbourofelines as terminal members of the Nimravidae, sister to the Nimravini (0.91 posterior probability), a relationship not found in prior cladistic studies. Ancestral area estimation performed in the R package BioGeoBEARS best supports a primarily European paleobiogeographic center for the barbourofelines with multiple dispersal events to other continents, a finding in direct opposition to past hypotheses for this group. Furthermore, new patterns in convergence between nimravids and machairodontines were revealed via Bayesian ancestral state estimation in BayesTraits. Results support a hypothesis of cats copying nimravids, and nimravids cats in certain aspects of sabertooth morphology, and not total evolutionary independence of these features as typically envisioned.
A pattern seems to be clear with extinctions as someone else pointed out, original colonists (whether that be native Americans, aboriginals etc) wipe out the majority of the megafauna, and the second European wave of colonists do a substantial amount of damage to what's left. In short, human colonisation of any kind is bad for fauna.
Large-scale reptile extinctions following European colonization of the Guadeloupe Islands Abstract Large-scale extinction is one of the defining challenges of our time, as human processes fundamentally and irreversibly reshape global ecosystems. While the extinction of large animals with popular appeal garners widespread public and research interest, the importance of smaller, less “charismatic” species to ecosystem health is increasingly recognized. Benefitting from systematically collected fossil and archaeological archives, we examined snake and lizard extinctions in the Guadeloupe Islands of the Caribbean. Study of 43,000 bone remains across six islands revealed a massive extinction of 50 to 70% of Guadeloupe’s snakes and lizards following European colonization. In contrast, earlier Indigenous populations coexisted with snakes and lizards for thousands of years without affecting their diversity. Study of archaeological remains provides insights into the causes of snake and lizard extinctions and shows that failure to consider fossil-derived data probably contributes to substantial underestimation of human impacts to global biodiversity.
A database of the body size of all fossil carnivores
GitHub - sorenfaurby/CarniFOSS: A database of the body size of all fossil carnivores |
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