27 research outputs found

    Parent‐Offspring Conflict in the Evolution of Vertebrate Reproductive Mode

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    Abstract: We propose and evaluate the hypothesis that parent‐offspring conflict over the degree of maternal investment has been one of the main selective factors in the evolution of vertebrate reproductive mode. This hypothesis is supported by data showing that the assumptions of parent‐offspring conflict theory are met for relevant taxa; the high number of independent origins of viviparity, matrotrophy (direct maternal‐fetal nutrient transfer), and hemochorial placentation (direct fetal access to the maternal bloodstream); the extreme diversity in physiological and morphological aspects of viviparity and placentation, which usually cannot be ascribed adaptive significance in terms of ecological factors; and divergent and convergent patterns in the diversification of placental structure, function, and developmental genetics. This hypothesis is also supported by data demonstrating that embryos and fetuses actively manipulate their interaction with the mother, thereby garnishing increased maternal resources. Our results indicate that selection may favor adaptations of the mother, the fetus, or both in traits related to reproductive mode and that integration of physiological and morphological data with evolutionary ecological data will be required to understand the adaptive significance of interspecific variation in viviparity, matrotrophy, and placentation

    Evaluating risk effects of industrial features on woodland caribou habitat selection in west central Alberta using agent-based modelling

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    AbstractAlberta woodland caribou (Rangifer tarandus) are classified as threatened in Canada, and a local population in the west-central region, the Little Smoky herd, is at immediate risk of extirpation due, in part, to anthropogenic activities such as oil, gas, and forestry that have altered the ecosystem dynamics. To investigate these impacts, we have developed a spatially explicit, agent-based model (ABM) to simulate winter habitat selection and use of woodland caribou, and to determine the relative impacts of different industrial features on caribou habitat-selection strategies. The ABM model is composed of cognitive caribou agents possessing memory and decision-making heuristics that act to optimize tradeoffs between energy acquisition and disturbance. A set of environmental data layers was used to develop a virtual grid representing the landscape over which caribou move. This grid contained forage-availability, energy-content, and predation-risk values. The model was calibrated using GPS data from caribou radio collars (n = 13) deployed over six months from 2004 to 2005, representing caribou winter activities. Additional simulations were conducted on caribou habitat-selection strategies by assigning industrial features (i.e., roads, seismic lines, pipelines, well sites, cutblocks and burns) different levels of disturbance depending on their type, age, and density. Differences in disturbance effects between industry features were confirmed by verifying which resultant simulations of caribou movement patterns most closely match actual caribou distributions and other patterns extracted from the GPS data. The results elucidate the degree to which caribou perceive different industry features as disturbance, and the differential energetic costs associated with each, thus offering insight into why caribou are choosing the habitats they use, and consequently, the level and type of industry most likely to affect their bioenergetics and fitness

    Dog-walking behaviours affect gastrointestinal parasitism in park-attending dogs

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    In urban parks, dogs, wildlife and humans can be sympatric, introducing the potential for inter- and intra-specific transmission of pathogens among hosts. This study was conducted to determine the prevalence of zoonotic and non-zoonotic gastrointestinal parasites in dogs in Calgary city parks, and assess if dog-walking behaviour, park management, history of veterinary care, and dog demographics were associated with parasitism in dog

    Investing in monarch conservation: understanding private funding dynamics

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    Non-profit environmental organizations (NGOs) rely heavily on external donors to fulfill their mandates. However, forecasting donations for long-term planning is an elusive task at best. The non-compulsory nature of donation requires NGOs to understand how donors’ attention and funding allocations change over time as conservation scenarios change and incorporate these insights into their budgeting plans. We hypothesize that an NGO can hinder its capacity to reach its conservation goals by neglecting its donor-NGO-natural system (DNNS), which is reactive to the socio-ecological context. To test our hypothesis, we compared the ecological outcomes derived from a budgeting strategy assuming donors have a fixed willingness to pay throughout the program (open-loop) against the reality that donor preferences change over time (closed-loop) based on the evolving ecological context, partly driven by the program’s actions. Our analysis was performed using two different willingness to pay (WTP) behavioural models, one representing donors informed about the success of the program supported (GPI), and another without such information (GPI), evidencing how the underlying assumptions about the target donors can radically change the organization’s fundraising strategy. Next, we used our closed-loop approach to estimate NGO’s optimal yearly donation requests to achieve a conservation target. Finally, we tested the consequences of presuming an incorrect WTP behavioural model while estimating optimal yearly donation requests by applying the optimization results from the previous step into a model parameterized with a different behavioural model. Our model was created by coupling a discrete choice experiment (DCE) and a systems dynamics model, developing a coupled social-ecological model of the eastern Monarch butterfly (Danaus plexippus), a charismatic long-distant migrant butterfly that has dwindled in numbers across North America mainly due to the increases in GMO agriculture. Our results showed a significant difference in donations received and ecological outcome forecasted by an open-loop model and the actual numbers obtained by the more real-life, closed-loop model, highlighting the importance of accounting for human behaviour during the planning phase of a long-term conservation strategy. Next, when we used our closed-loop to estimate optimal donation requests, the conservation objectives and funds raised were consistently and efficiently achieved, regardless of the underlying behavioural WTP model. We also designed novel visual tools from the behaviour WTP model exploration to bridge the gap between science insights obtained from DCEs and decision-making. However, when we used closed-loop optimal donation requests obtained from one WTP behaviour model into a simulation parameterized with different WTP behavioural models, considerable ecological and financial targets deviations arose. These deviations highlight the importance of acknowledging the dynamic nature of donor’s behaviour and the need to thoroughly characterize such behaviour. Finally, we introduce a novel forecasting tool that conservation managers will have at their disposal to improve the accuracy of their budget forecasting and, ultimately, increase the program’s success rate

    A Landscape-Level Assessment of Restoration Resource Allocation for the Eastern Monarch Butterfly

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    The Monarch butterfly eastern population (Danaus plexippus) is in decline primarily due to habitat loss. Current habitat restoration programs focus on re-establishing milkweed, the primary food resource for Monarch caterpillars, in the central United States of America. However, individual components of the Monarch life cycle function as part of an integrated whole. Here we develop the MOBU-SDyM, a migration-wide systems dynamics model of the Monarch butterfly migratory cycle to explore alternative management strategies’ impacts. Our model offers several advances over previous efforts, considering complex variables such as dynamic temperature-dependent developmental times, dynamic habitat availability, and weather-related mortality across the entire range. We first explored whether the predominant focus of milkweed restoration in the mid-range of the Monarch’s migration could be overestimating the Monarch’s actual habitat requirements. Second, we examined the robustness of using the recommended 1.2–1.6 billion milkweed stems as a policy objective when accounting for factors such as droughts, changes in temperature, and the stems’ effective usability by the Monarchs. Third, we used the model to estimate the number and distribution of stems across the northern, central, and southern regions of the breeding range needed to reach a self-sustainable long-term Monarch population of six overwintering hectares. Our analysis revealed that concentrating milkweed growth in the central region increases the size of the overwintering colonies more so than equivalent growth in the south region, with growth in the northern region having a negligible effect. However, even though simulating an increase in milkweed stems in the south did not play a key role in increasing the size of the overwintering colonies, it plays a paramount role in keeping the population above a critically small size. Abiotic factors considerably influenced the actual number of stems needed, but, in general, our estimates of required stems were 43–91% larger than the number of stems currently set as a restoration target: our optimal allocation efforts were 7.35, 92, and 0.15% to the south, central, and northern regions, respectively. Systems dynamics’ analytical and computational strengths provided us with new avenues to investigate the Monarch’s migration as a complex biological system and to contribute to more robust restoration policies for this unique species

    Monarch Butterfly Conservation Through the Social Lens: Eliciting Public Preferences for Management Strategies Across Transboundary Nations

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    The monarch butterfly (Danaus plexippus), an iconic species that migrates annually across North America, has steeply declined in numbers over the past decade. Across the species\u27 range, public, private, and non-profit organizations aim to reverse the monarch decline by engaging in conservation activities such as habitat restoration, larvae monitoring, and butterfly tagging. Urban residents can actively participate in these activities, yet their contribution can also be realized as an electorate body able to influence the design of conservation programs according to their interests. Little is known, however about their preferences toward the objectives and design of international monarch conservation policies. In this paper, we investigate these preferences via a survey design using Discrete Choice Experiments (DCEs) and Latent Class Analysis (LC) of urban residents across the main eastern migratory flyway in Ontario, Canada, and the eastern United States. Attributes in the DCE included the size and trend of overwintering butterfly colonies, the type of institution leading the conservation program, international allocation of funds, and the percentage of funds dedicated to research. From the general populace, we isolated respondents already engaged in monarch conservation activities to explore how they compare. We sent a smaller set of surveys deliberately withholding the expected-success forecast of the monarch recovery program to assess the value of information for urban residents within a conservation context. The LC distinguished three groups of respondents among urban residents: (1) the main group, labeled “Eager,” accounting for 72.4% of the sample, that showed a high potential for supporting conservation policies and had remarkable similarities with the monarch enthusiasts\u27 sample; (2) a “Pro Nation” group (18.4%) marked by their increased willingness to support conservation initiatives solely focused within their country of residence; and (3) an “Opinionated” segment (9.23%), that was highly reactive to changes of the leading institution, resources allocation, and economic contribution proposed. Key findings from this research reveal that to maximize potential support amongst urban residents in the monarch\u27s breeding range, a conservation strategy for the monarch butterfly should be led by not-for-profit organizations, should strive for transboundary cooperation, and should include the communication of anticipated ecological outcomes

    Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators

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    Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near‐top trophic‐level marine predators have been little studied in polar regions or with latitude. We quantified the large‐scale latitudinal variation of population‐ and individual‐level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within‐ and between‐individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within‐individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large‐scale spatial variation in ecological opportunity, suggesting species‐specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem

    Latitudinal variation in ecological opportunity and intraspecific competition indicates differences in niche variability and diet specialization of Arctic marine predators

    Get PDF
    Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near‐top trophic‐level marine predators have been little studied in polar regions or with latitude. We quantified the large‐scale latitudinal variation of population‐ and individual‐level niche size and IS in ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) using stable carbon and nitrogen isotope analysis on 379 paired ringed seal liver and muscle samples and 124 paired beluga skin and muscle samples from eight locations ranging from the low to high Arctic. We characterized both within‐ and between‐individual variation in predator niche size at each location as well as accounting for spatial differences in the isotopic ranges of potential prey. Total isotopic niche width (TINW) for populations of ringed seals and beluga decreased with increasing latitude. Higher TINW values were associated with greater ecological opportunity (i.e., prey diversity) in the prey fish community which mainly consists of Capelin (Mallotus villosus) and Sand lance (Ammodytes sp.) at lower latitudes and Arctic cod (Boreogadus saida) at high latitudes. In beluga, their dietary consistency between tissues also known as the within‐individual component (WIC) increased in a near 1:1 ratio with TINW (slope = 0.84), suggesting dietary generalization, whereas the slope (0.18) of WIC relative to TINW in ringed seals indicated a high degree of individual specialization in ringed seal populations with higher TINWs. Our findings highlight the differences in TINW and level of IS for ringed seals and beluga relative to latitude as a likely response to large‐scale spatial variation in ecological opportunity, suggesting species‐specific variation in dietary plasticity to spatial differences in prey resources and environmental conditions in a rapidly changing ecosystem
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