Rhinoceros Poachers Targeted in South Africa as Killings Surge to a Record - Bloomberg

Rhinoceros Poachers Targeted in South Africa as Killings Surge to a Record - Bloomberg: "Rhino poachers are using helicopters to find rhinos both in national parks and on private game farms and the Endangered Wildlife Trust is working with aviation authorities to find ways of tracking low-flying helicopters. Game farmers are also being urged to take DNA samples from their stock to help prosecute poachers by linking dead rhinos to horns. South Africa is home to 93 percent of Africa’s rhino population"

Estimating Economic Carrying Capacity for an Ungulate Guild in Western Canada

BSP :Estimating Economic Carrying Capacity for an Ungulate Guild in Western Canada:Using linear programming, we explored optimal allocation of forage resources for bison (Bison bison bison), moose (Alces andersoni), wapiti (Cervus elaphus manitobensis) and deer (Odocoileus virginianus and O. hemionus) to maximize ungulate biomass and numbers, when constrained by use of the major forage classes and minimum viable populations (MVP) of those ungulate species that do not cross the boundary fence (bison and wapiti). Maximum numbers of animals were achieved by a stocking combination dominated by deer and bison, whereas maximum biomass was attained when bison and moose were abundant but deer were absent. Wapiti remained at MVP during all solutions. Optimal solutions consistent with current ungulate densities were associated with 7 to 11% forage removal. This is less than normally assumed for sustainable forage use, and may reflect the need to account for other biotic and abiotic losses to forage in carrying capacity models for which ungulate densities can be constrained by availability of a preferred forage class (e.g., grass) as well as forage quality.

ScienceDirect - Ecological Modelling : A parsimonious optimal foraging model explaining mortality patterns in Serengeti wildebeest

ScienceDirect - Ecological Modelling : A parsimonious optimal foraging model explaining mortality patterns in Serengeti wildebeest. Based on data collected over 24 years in the Serengeti in Tanzania, Sinclair and Arcese (1995) indicated that the sensitivity of blue wildebeest Connochaetes taurinus to predation risk by lions Panthera leo may cause them to change habitats between open (low risk) and wooded (risky) habitats. They found that, in poor rainfall years, predators kill wildebeest that are in better condition than those that die of natural causes. In good rainfall years, predators kill wildebeest that are in worse condition than those that die of natural causes. Sinclair and Arcese (1995) proposed the “predation-sensitive food” hypothesis. This hypothesis suggests that, as food becomes limiting, animals take greater risks to obtain more food, and some of these animals are killed. I propose a more parsimonious hypothesis based on the marginal value theorem that is consistent with the observations made by Sinclair and Arcese (1995). Wildebeest follow a single decision rule in good and poor rainfall years, viz. move when foraging elsewhere increases your rate of intake of nutritious food. Similarly, predators follow a singledecision rule in good and poor rainfall years, viz. take the prey item that maximizes the intake of energy per unit effort expended.

Structure and Dynamics of Ecological Networks -- Bascompte 329 (5993): 765 -- Science

Structure and Dynamics of Ecological Networks -- Bascompte 329 (5993): 765 -- Science: "Ecologists have a long tradition of studying how species interact. Almost all of this work, however, has focused on networks involved in a single type of interaction. For instance, ecologists have studied either 'antagonistic' interactions, such as those in who-eats-who food webs, or, more recently, mutually beneficial interactions, such as those between flowering plants and their insect pollinators. Very few studies have embraced both (1–3), leaving a key question: To what degree do different kinds of interactions lead to ecological networks with different structures? The answer is crucial to understanding the suite of ecological, evolutionary, and coevolutionary processes that shape these networks and how they may respond to future changes. On page 853 of this issue, Th�bault and Fontaine (4) take an important step forward by comparing the structure and dynamics of antagonistic and mutualistic networks."

Spatial distribution and deviations from the IFD when animals forage over large resource patches -- Miller and Coll 21 (5): 927 -- Behavioral Ecology

Spatial distribution and deviations from the IFD when animals forage over large resource patches -- Miller and Coll 21 (5): 927 -- Behavioral Ecology: "Animal distribution among resource patches in a habitat has for the most part been treated as a deterministic process. When patch size is large compared with the animal’s foraging range, individuals assess the quality of the patch by sampling small fractions of it, the sampled area (SA). In doing so, each individual may experience different patch qualities because of stochastic distribution of animal numbers in different SAs."

ScienceDirect - Animal Behaviour : Effects of group composition on the grazing behaviour of herbivores

ScienceDirect - Animal Behaviour : Effects of group composition on the grazing behaviour of herbivores: "Animal behaviour is often a function of the animal’s physiological state. Groups of animals will often contain individuals with a range of physiological states and the grazing behaviour of herbivores is affected by their physiological state. This study compared the grazing decisions of animals in groups of single and mixed physiological states. Using a grazing model that simulated individual herbivore behaviour in relation to environmental distributions of forage resource (grass) and parasites (faeces), we tested the hypothesis that an animal’s level of parasite exposure via the faecal–oral route is affected by the composition of physiological states in the group."

AFP: Extinct mammoth tusks fill elephant ivory ban gap

AFP: Extinct mammoth tusks fill elephant ivory ban gap: "HONG KONG — Stumped by a ban designed to save elephants from extinction, Hong Kong's master carvers turned to a long dead species that left thousands of tonnes of frozen ivory in Siberian mass graves.
Mammoth tusks, intricately carved to depict anything from devotional Buddhist scenes and teeming wildlife to bizarre erotic fantasies, now make up most of the ivory for sale in the city.
The international trade in elephant ivory, with rare exceptions, has been outlawed since 1989 after populations of the African giants dropped from the millions in the mid-20th century to some 600,000 by the end of the 1980s.
The ban left hundreds of traditional carvers in the south China region facing an uncertain future, until they turned to a global stock of ancient tusks buried mostly in Siberia, but also in Europe and north America."

Spatial autocorrelation: an overlooked concept in behavioral ecology -- Valcu and Kempenaers 21 (5): 902 -- Behavioral Ecology

Spatial autocorrelation: an overlooked concept in behavioral ecology -- Valcu and Kempenaers 21 (5): 902 -- Behavioral Ecology: "The general aim of this paper is to draw the attention of behavioral ecologists to the phenomenon of SAC. Specifically, we aim 1) to provide examples of spatially autocorrelated variables, indicating that SAC is widespread in variables commonly used in behavioral ecology studies, 2) to show why it is important to take SAC into account, and 3) to point to some tools to explore and model it."

Quantification and Simulation of Grazing Impacts on Soil Water in Boreal Grasslands - Donkor - 2006 - Journal of Agronomy and Crop Science - Wiley Online Library

Quantification and Simulation of Grazing Impacts on Soil Water in Boreal Grasslands - Donkor - 2006 - Journal of Agronomy and Crop Science - Wiley Online Library: "We conducted a 2-year study in central Alberta to quantify and simulate the soil water status of boreal grasslands under three grazing systems using wapiti (Cervus elaphus Canadensis), viz. (1) ungrazed control (UNG), (2) high intensity [4.16 animal unit month per ha (AUM) ha−1 ] short-duration grazing (SDG) and (3) moderate intensity (2.08 AUM ha−1) continuous grazing (CG). Soil water was measured from May 1997 to September 1998 to a depth of 15�cm. Total annual precipitation in 1997 and 1998 was 494 and 429�mm respectively. In both years grazing treatments reduced soil water. Soil water content under SDG was significantly (P�<�0.05) lower than CG. Simulation of soil water on each grazing system was conducted using PASTURE, a simple compartmental system dynamics model."

Challenges of foraging on a high-quality but unpredictable food source: the dynamics of grass production and consumption in savanna grazing lawns - Bonnet - 2010 - Journal of Ecology - Wiley Online Library

Challenges of foraging on a high-quality but unpredictable food source: the dynamics of grass production and consumption in savanna grazing lawns - Bonnet - 2010 - Journal of Ecology - Wiley Online Library: "Grazing lawns are short grassland areas where intense grazing maintains grass in an early growth stage. These areas represent a source of high-quality forage for herbivores. However, as herbivores continually remove nearly all the newly accumulated biomass, instantaneous resource availability depends on the dynamics of grass growth. We investigate how production and consumption inside grazing lawns are synchronized. We then explore how that synchronization affects the ability of large herbivores to use these lawns. We also provide a critical comparison between grazing lawns and intensively managed grasslands in livestock farms. We investigated vegetation production and herbivore grazing activity during a wet and a dry season using clipping experiments and direct observation in two grazing lawns in a South African savanna."

A system for predicting energy and protein requirements of wild ruminants - Hackmann - 2010 - Zoo Biology - Wiley Online Library

A system for predicting energy and protein requirements of wild ruminants - Hackmann - 2010 - Zoo Biology - Wiley Online Library: "Wild ruminants require energy and protein for the normal function. I developed a system for predicting these energy and protein requirements across ruminant species and life stages. This system defines requirements on the basis of net energy (NE), net protein (NP), and ruminally degraded protein (RDP). Total NE and NP requirements are calculated as the sum of NE and NP required for several functions (maintenance, activity, thermoregulation, gain, lactation, and gestation). To estimate the requirements for each function, I collected data predominantly for wild species and then formulated allometric and other equations that predict requirements across species."

Agent-based Modeling of Animal Movement: A Review - Tang - 2010 - Geography Compass - Wiley Online Library

Agent-based Modeling of Animal Movement: A Review - Tang - 2010 - Geography Compass - Wiley Online Library: "Animal movement is a complex spatiotemporal phenomenon that has intrigued researchers from many disciplines. Interactions among animals, and between animals and the environments that they traverse, play an important role in the development of the complex ecological and social systems in which they are embedded. Agent-based models have been increasingly applied as a computational approach to the study of animal movement across landscapes. In this article, we present a review of agent-based models in which the simulation of animal movement processes and patterns is the central theme."

Irruptive Dynamics and Vegetation Interactions - Dynamics of Large Herbivore Populations in Changing Environments: Towards Appropriate Models - Gross - Wiley Online Library

Irruptive Dynamics and Vegetation Interactions - Dynamics of Large Herbivore Populations in Changing Environments: Towards Appropriate Models - Gross - Wiley Online Library: "irruptive dynamics and vegetation interactions;irruption, leading to severe mortality associated with vegetation degradation;concept of irruptive herbivore dynamics, by Leopold;herbivore–vegetation interaction models and herbivore dynamics;irruptive dynamics, ungulate populations on islands-prone to extreme irruptions;Isle Royale population - standing out for cyclic behavior;wolf population crash on Isle Royale - precipitating irruption of moose;irruption effects on vegetation;harsh weather, and population crashes - weather and food availability interaction;large herbivore management - hinging on philosophical basis of management"

THE ORIGINS OF SEXUAL DIMORPHISM IN BODY SIZE IN UNGULATES - P�rez-Barber�a - 2007 - Evolution - Wiley Online Library

THE ORIGINS OF SEXUAL DIMORPHISM IN BODY SIZE IN UNGULATES - P�rez-Barber�a - 2007 - Evolution - Wiley Online Library: "Jarman (1974) proposed a series of relationships between habitat use, food dispersion, and social behavior and hypothesized a series of evolutionary steps leading to sexual dimorphism in body size through sexual selection in African antelope species. The hypothesis states that sexual size dimorphism evolved in a three-step process. Initially, ancestral monomorphic and monogamous ungulate species occupying closed habitats radiated into open grassland habitats."

Correlation of relative muzzle width and relative incisor width with dietary preference in ungulates - JANIS - 2008 - Zoological Journal of the Linnean Society - Wiley Online Library

Correlation of relative muzzle width and relative incisor width with dietary preference in ungulates - JANIS - 2008 - Zoological Journal of the Linnean Society - Wiley Online Library: "Qualitative observations suggest that grazing ungulates have relatively broader muzzles than browsing ones, and that grazers have incisors that are all of a similar size, as opposed to the large central and smaller lateral incisors seen in browsers. These differences may be correlated respectively with the need for grazing ungulates to maintain a large daily intake, or for browsing ungulates to forage selectively in a stand of vegetation."

Incorporating Collateral Data in Conservation Biology - LINACRE - 2004 - Conservation Biology - Wiley Online Library

Incorporating Collateral Data in Conservation Biology - LINACRE - 2004 - Conservation Biology - Wiley Online Library: "Conservation biologists often need to set ecological modeling assumptions or estimate parameters from sparse data. In some cases this problem can be addressed by incorporating data from closely related species or from the same species at different sites (i.e., collateral data). Currently no structured methods exist for incorporating such information."