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  1. null (Ed.)

    Introduction:As challenges to biodiversity mount, land-use policies have been implemented to balance human needs and the integrity of ecological systems. One such program, Payments for Ecosystem Services (PES), incentivizes resource users to protect ecosystem services and has been implemented around the world to reduce soil erosion, create or improve wildlife habitats, and improve water quality and other environmental goals. The PES policy, at its core, is a concept that aims to capture the reciprocal relationships between human systems and ecological function and process. As such, PES epistemologically embodies a coupled human and natural systems approach.

    Outcomes:Yet, despite this conceptual alignment, the on-the-ground implementation or evaluation of PES typically does not adopt this coupled approach and PES programs have little integration between socioeconomic, sociocultural, human demographic, and ecological elements. To advance the evolution of PES, we consider what and how socioeconomic and ecological factors have been incorporated into PES program implementation and evaluation. We also present a conceptual model to articulate how PES research can capture the reciprocal relationships among socioeconomics, demography, and ecology and discuss the quantitative modeling approaches that can support this conceptual development, i.e., structural equation and agent-based modeling, and latent trajectory models.

    Conclusions:By strengthening the conceptual framework for PES within a coupled human and natural systems approach and identifyinganalytical approaches that can be used to quantify and characterize these complex cross-disciplinary relationships, we aim to support the evolution and advancement of PES, in service of more meaningful and positive outcomes for human well-being and ecological sustainability.

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  3. Abstract

    Immune function plays an important role in an animal's defense against infectious disease. In reptiles, immune responses may be complex and counterintuitive, and diagnostic tools used to identify infection, such as induced antibody responses are limited. Recent studies using gene transcription profiling in tortoises have proven useful in identifying immune responses to various intrinsic and extrinsic stressors. As part of a larger experiment with Mojave desert tortoises (Gopherus agassizii), we facilitated the transmission of the pathogenic bacteria,Mycoplasma agassizii(Myag), to naïve adults and measured innate and induced immune reactions over time. Specifically, we evaluated clinical condition, presence of Myag in the nasal/oral cavity, induced antibody responses specific to Myag, and measured molecular reactions (gene transcript profiles) in 15 captive tortoises classified as naïve, exposed, or infected and 14 wild tortoises for comparison. Myag was confirmed inside the nasal/oral cavity in exposed tortoises within 30–60 days of introduction to infected animals, yet we did not detect Myag specific induced antibody responses in these individuals until 420–595 days post exposure. Surprisingly, we found no overall differences in the gene transcript profiles between our experimental treatment groups throughout this study. This work highlights the complexities in assessing immune function and diagnosing pathogen related infections in tortoises and other reptiles.

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