Animal Populations do NOT Respond Uniformly to Climate Change

Geographical variation in species' population responses to changes in temperature and precipitation

Authors:

Pearce-Higgins et al

Abstract:

Despite increasing concerns about the vulnerability of species' populations to climate change, there has been little overall synthesis of how individual population responses to variation in climate differ between taxa, with trophic level or geographically. To address this, we extracted data from 132 long-term (greater than or equal to 20 years) studies of population responses to temperature and precipitation covering 236 animal and plant species across terrestrial and freshwater habitats. Our results identify likely geographical differences in the effects of climate change on populations and communities in line with macroecological theory. Temperature tended to have a greater overall impact on populations than precipitation, although the effects of increased precipitation varied strongly with latitude, being most positive at low latitudes. Population responses to increased temperature were generally positive, but did not vary significantly with latitude. Studies reporting significant climatic trends through time tended to show more negative effects of temperature and more positive effects of precipitation upon populations than other studies, indicating climate change has already impacted many populations. Most studies of climate change impacts on biodiversity have focused on temperature and are from middle to high northern latitudes. Our results suggest their findings may be less applicable to low latitudes.

What's Weirder Than Weird? Turtles Grooming a Warthog (not kidding)

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Chimpanzees are Just Inherently Violent

Of all of the world's species, humans and chimpanzees are some of the only to engage in coordinated attacks on other members of their same species. Jane Goodall was among the first to introduce the occurrence of lethal inter-community killings and since then primatologists and anthropologists have long debated the concept of warfare in this genus. Research theories have pointed to increased gains and benefits of killing off competitors and opening up increased access to key resources such as food or mates. In contrast, others have argued that warfare is a result of human impact on chimpanzees, such as habitat destruction or food provisioning, rather than adaptive strategies.

New research from an international coalition of ape researchers, published September 18 in the journal Nature, has shed new light on the subject, suggesting that human encroachment and interference is not, as previous researchers have claimed, an influential predictor of chimp-on-chimp aggression.

The study began as a response to a growing number of commentators claiming that chimpanzee violence was caused by human impacts. "This is an important question to get right. If we are using chimpanzees as a model for understanding human violence, we need to know what really causes chimpanzees to be violent," said University of Minnesota researcher Michael L. Wilson, lead author on the study.

"Humans have long impacted African tropical forests and chimpanzees, and one of the long-standing questions is if human disturbance is an underlying factor causing the lethal aggression observed," explained co-author David Morgan, PhD, research fellow with the Lester E Fisher Center for the Study and Conservation of Apes at Lincoln Park Zoo in Chicago. Morgan has studied chimpanzees deep in the forests of Republic of Congo for 14 years. "A key take-away from this research is that human influence does not spur increased aggression within or between chimpanzee communities."

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Evidence of Roughhousing by Tyrannosaurs

Unexpected behavior in the Cretaceous: tooth-marked bones attributable to tyrannosaur play

Authors:

Rothschild

Abstract:

Attributing behavior in extinct animals is predicated on identification of anatomy or pathology analogous to that present and recognized in contemporary animals (ROTHSCHILD & MARTIN 2006). While TANKE & CURRIE (1998) noted the difficulty of directly recognizing dinosaur behavior, one approach is to examine biotic-derived environmental alterations. For the analysis of utilization of potential dietary components by theropod dinosaurs, this means examining the damage they produced in manipulation of carcasses or bony components thereof. Application of deductive reasoning to tooth marks on isolated dinosaur bones and fragments excludes the usual suspects (scavenging and predation), leaving attribution to a behavior not previously considered. The pattern of bite marks in isolated bones, and especially in isolated ceratopsian occipital condyles, is incompatible with feeding activities, but is characteristic of that found with play by contemporary animals. Deductive reasoning leads to an alternative explanation to feeding behaviors for isolated, tooth-marked bones: Tyrannosaurids played with those bones.

Complex Feeding Patterns Five Million Years Before The Precambrian–Cambrian Boundary

Trace Fossils with Spreiten from the Late Ediacaran Nama Group, Namibia: Complex Feeding Patterns Five Million Years Before The Precambrian–Cambrian Boundary

Authors:

Macdonald et al

Abstract:

Here we describe large, complex trace fossils in the late Ediacaran Omkyk Member of the Zaris Formation, Nama Group, southern Namibia. The horizontal trace fossils are preserved on a number of talus blocks from a bedding plane of a cm-thick sandstone lens from a single stratigraphic horizon less than 100 m below an ash bed dated at 547.3 ± 0.7 Ma. The forms consist of overlapping U-shaped spreiten elements with parallel limbs surrounded by an outer tube. Individual U-shaped elements are 0.2 to 1 cm in diameter, the outer tube is less than 3 mm in diameter, and the forms as a whole range from 5 to 30 cm long and 3 to 10 cm wide. The specimens commonly show a change in direction and change in diameter. The morphology of these trace fossils is comparable to backfill structures, particularly specimens of Paleozoic Zoophycos from shallow water environments. Here we interpret these horizontal spreiten-burrows to record the grazing of the trace-maker on or below a textured organic surface. The identification of large late Ediacaran trace fossils is consistent with recent reports of backfilled horizontal burrows below the Precambrian–Cambrian boundary and is suggestive of the appearance of complex feeding habits prior to the Cambrian trace fossil explosion.

The Evolution of Behavioral Complexity Across the Ediacaran/Cambrian Boundary

When Life Got Smart: The Evolution of Behavioral Complexity Through the Ediacaran and Early Cambrian of NW Canada

Authors:

Carbone et al

Abstract:

Ediacaran and early Cambrian strata in NW Canada contain abundant trace fossils that record the progressive development of complex behavior in early animal evolution. Five feeding groups can be recognized: microbial grazing, deposit-feeding, deposit-feeding/predatory, filter-feeding/predatory, and arthropod tracks and trails. The lower Blueflower Formation (ca. 560–550 Ma) contains abundant burrows that completely cover bedding surfaces with small (∼1 mm diameter) cylindrical burrows that were strictly restricted to microbial bedding surfaces and exhibited only primitive and inconsistent avoidance strategies. The upper Blueflower contains three-dimensional avoidance burrows and rare filter-feeding or possibly predatory burrows, suggesting increased behavioral responses in food gathering that marked the beginning of the agronomic revolution in substrate utilization. Cambrian strata of the Ingta Formation contain systematically meandering burrows and more diverse feeding strategies, including the onset of treptichnid probing burrows that may reflect predation. These observations imply that Ediacaran burrowers were largely characterized by crude, two-dimensional avoidance meanders that represented simple behavioral responses of individual burrowers to sensory information, and that the subsequent development of more diverse and complex feeding patterns with genetically programmed search pathways occurred during the earliest stages of the Cambrian explosion. These observations further imply that changes occurred in both the food source and substrate during the ecological transition from Proterozoic matgrounds to Phanerozoic mixgrounds.

Complexity in Animal Behavior

New to Me: A Japanese Pufferfish Species is an Underwater Bower Bird