The International Olympic Committee framework on fairness, inclusion and nondiscrimination on the basis of gender identity and sex variations does not protect fairness for female athletes

The International Olympic Committee (IOC) recently published a framework on fairness, inclusion, and nondiscrimination on the basis of gender identity and sex variations. Although we appreciate the IOC's recognition of the role of sports science and medicine in policy development, we disagree with the assertion that the IOC framework is consistent with existing scientific and medical evidence and question its recommendations for implementation. Testosterone exposure during male development results in physical differences between male and female bodies; this process underpins male athletic advantage in muscle mass, strength and power, and endurance and aerobic capacity. The IOC's “no presumption of advantage” principle disregards this reality. Studies show that transgender women (male-born individuals who identify as women) with suppressed testosterone retain muscle mass, strength, and other physical advantages compared to females; male performance advantage cannot be eliminated with testosterone suppression. The IOC's concept of “meaningful competition” is flawed because fairness of category does not hinge on closely matched performances. The female category ensures fair competition for female athletes by excluding male advantages. Case-by-case testing for transgender women may lead to stigmatization and cannot be robustly managed in practice. We argue that eligibility criteria for female competition must consider male development rather than relying on current testosterone levels. Female athletes should be recognized as the key stakeholders in the consultation and decision-making processes. We urge the IOC to reevaluate the recommendations of their Framework to include a comprehensive understanding of the biological advantages of male development to ensure fairness and safety in female sports

Effects of Consumer Interactions on Benthic Resources and Ecosystem Processes in a Neotropical Stream

The effect of consumers on their resources has been demonstrated in many systems but is often confounded by trophic interactions with other consumers. Consumers may also have behavioral and life history adaptations to each other and to co-occurring predators that may additionally modulate their particular roles in ecosystems. We experimentally excluded large consumers from tile periphyton, leaves and natural benthic substrata using submerged electrified frames in three stream reaches with overlapping consumer assemblages in Trinidad, West Indies. Concurrently, we assessed visits to (nonelectrified) control frames by the three most common large consumers–primarily insectivorous killifish (Rivulus hartii), omnivorous guppies (Poecilia reticulata) and omnivorous crabs (Eudaniela garmani). Consumers caused the greatest decrease in final chlorophyll a biomass and accrual rates the most in the downstream reach containing all three focal consumers in the presence of fish predators. Consumers also caused the greatest increase in leaf decay rates in the upstream reach containing only killifish and crabs. In the downstream reach where guppies co-occur with predators, we found significantly lower benthic invertebrate biomass in control relative to exclosure treatments than the midstream reach where guppies occur in the absence of predators. These data suggest that differences in guppy foraging, potentially driven by differences in their life history phenotype, may affect ecosystem structure and processes as much as their presence or absence and that interactions among consumers may further mediate their effects in these stream ecosystems

Energy Flow and the Trophic Basis of Macroinvertebrate and Amphibian Production in a Neotropical Stream Food Web

1. Despite the typically high taxonomic and functional diversity of tropical habitats, little is known about the roles of individual consumers in their ecosystem structure and function. We studied the trophic basis of production in a tropical headwater stream by identifying major sources of energy, measuring energy flow through consumers and characterising interactions among trophic levels and functional groups. 2. We examined gut contents of 18 dominant macroinvertebrate and two tadpole taxa and used these data, along with previously published estimates of secondary production, to quantify food‐web structure and energy flow pathways. We also examined the prevalence of omnivory and patterns of resource consumption across seasons and habitats. 3. Non‐algal biofilm, a heterogeneous polysaccharidic matrix, was the most utilised food resource in the stream. Contrary to some studies of Old World tropical stream food webs, detrital energy sources were consumed at relatively high rates and contributed significantly to overall energy flow, although much of this was attributable to a single shredder taxon. Algal consumption rates were similar to values reported for temperate streams and were highest during the dry season. 4. Omnivory was prevalent across all functional groups, particularly predators, suggesting traditional functional and trophic assignments based on temperate regions may not be appropriate for tropical systems. Seasonal patterns of resource consumption appeared linked to hydrological disturbance. 5. This is the first study to provide quantitative estimates of energy flow through a neotropical stream food web. Extirpation and extinction rates in tropical freshwater habitats are high; our study provides baseline information for conservation and management of remaining systems, and for quantifying the consequences of further losses of biodiversity such as ongoing amphibian declines

Mean (±1SE) visitation by guppies, killifish and crabs in all three stream reaches during day and night.

<p>Total daily mean was based on 12 hr diel periods and weighted to compensate for fewer night observations.</p><p>NA = not applicable (guppies not present in upstream reach).</p

Ecological and life history differences of 2 focal consumers in 3 reaches.

<p>Ecological and life history differences of 2 focal consumers in 3 reaches.</p

Mean (±1SE) response values in control (C) and exclusion (E) treatments for all three reaches. Significantly larger values (<i>P</i><.05) for each treatment pair indicated in bold.

<p>Chlorophyll <i>a</i> biomass and periphyton AFDM (ash-free dry mass) collected in week 3 for all reaches.</p><p>Invertebrate biomass and abundance collected after 4 weeks in upstream and midstream reaches, after 3 weeks in downstream reach.</p

Time series plot for chlorophyll a and leaf matter.

<p>Raw data (circles) and predicted values (curves) from mixed model analyses of periphyton chlorophyll <i>a</i> accrual rates (left panels) and leaf decomposition (right panels). Responses in controls (C) are solid symbols and lines, exclosures (E) are hollow symbols and dashed lines. Periphyton biomasses were evaluated at day 20 or 21 of the experiment.</p

The IOC framework on fairness, inclusion and non-discrimination on the basis of gender identity and sex variations does not protect fairness for female athletes

The International Olympic Committee (IOC) recently published a Framework on Fairness, Inclusion, and Non-discrimination on the Basis of Gender Identity and Sex Variations. Although we appreciate the IOC's recognition of the role of sports science and medicine in policy development, we disagree with the assertion that the IOC Framework is consistent with existing scientific and medical evidence and question its recommendations for implementation.Testosterone exposure during male development results in physical differences between male and female bodies; this process underpins male athletic advantage in muscle mass, strength and power, and endurance and aerobic capacity. The IOC's ”no presumption of advantage” principle disregards this reality. Studies show that transgender women (male-born individuals who identify as women) with suppressed testosterone retain muscle mass, strength, and other physical advantages compared to females; male performance advantage cannot be eliminated with testosterone suppression.The IOC's concept of “meaningful competition” is flawed because fairness of category does not hinge on closely-matched performances. The female category ensures fair competition for female athletes by excluding male advantages. Case-by-case testing for transgender women may lead to stigmatisation and cannot be robustly managed in practice.We argue that eligibility criteria for female competition must consider male development rather than relying on current testosterone levels. Female athletes should be recognized as the key stakeholders in the consultation and decision-making processes. We urge the IOC to re-evaluate the recommendations of their Framework to include a comprehensive understanding of the biological advantages of male development to ensure fairness and safety in female sports.<br/