The human touch: a meta-analysis of anthropogenic effects on plant-pollinator interaction networks.

Background: Anthropogenic activities significantly impact natural ecosystems, leading to alterations in plant and pollinator diversity and abundance. These changes often result in shifts within interacting communities, potentially reshaping the structure of plant-pollinator interaction networks. Given the escalating human footprint on habitats, evaluating the response of these networks to anthropization is critical for devising effective conservation and management strategies. Methods: We conducted a comprehensive review of the plant-pollinator network literature to assess the impact of anthropization on network structure. We assessed network metrics such as nestedness measure based on overlap and decreasing fills (NODF), network specialization (H2'), connectance (C), and modularity (Q) to understand structural changes. Employing a meta-analytical approach, we examined how anthropization activities, such as deforestation, urbanization, habitat fragmentation, agriculture, intentional fires and livestock farming, affect both plant and pollinator richness. Results: We generated a dataset for various metrics of network structure and 36 effect sizes for the meta-analysis, from 38 articles published between 2010 and 2023. Studies assessing the impact of agriculture and fragmentation were well-represented, comprising 68.4% of all studies, with networks involving interacting insects being the most studied taxa. Agriculture and fragmentation reduce nestedness and increase specialization in plant-pollinator networks, while modularity and connectance are mostly not affected. Although our meta-analysis suggests that anthropization decreases richness for both plants and pollinators, there was substantial heterogeneity in this regard among the evaluated studies. The meta-regression analyses helped us determine that the habitat fragment size where the studies were conducted was the primary variable contributing to such heterogeneity. Conclusions: The analysis of human impacts on plant-pollinator networks showed varied effects worldwide. Responses differed among network metrics, signaling nuanced impacts on structure. Activities like agriculture and fragmentation significantly changed ecosystems, reducing species richness in both pollinators and plants, highlighting network vulnerability. Regional differences stressed the need for tailored conservation. Despite insights, more research is crucial for a complete understanding of these ecological relationships.

Myiarchus flycatchers are the primary seed dispersers of Bursera longipes in a Mexican dry forest.

We evaluated the seed dispersal of Bursera longipes by birds along a successional gradient of tropical dry forest (TDF) in southwestern Mexico. B. longipes is an endemic tree to the TDF in the Balsas basin. The relative abundance of frugivorous birds, their frequency of visits to B. longipes and the number of removed fruits were recorded at three study sites with different stages of forest succession (early, intermediate and mature) characterized by distinct floristic and structural elements. Flycatchers of the Myiarchus and Tyrannus genera removed the majority of fruits at each site. Overall, visits to B. longipes were less frequent at the early successional site. Birds that function as legitimate dispersers by consuming whole seeds and regurgitating or defecating intact seeds in the process also remove the pseudoaril from seeds, thereby facilitating the germination process. The highest germination percentages were recorded for seeds that passed through the digestive system of two migratory flycatchers: M. cinerascens and M. nutingii. Perch plants, mainly composed of legumes (e.g., Eysenhardtia polystachya, Acacia cochliacantha, Calliandra eryophylla, Mimosa polyantha), serve also as nurse plants since the number of young individuals recruited from B. longipes was higher under these than expected by chance. This study shows that Myiarchus flycatchers are the most efficient seed dispersers of B. longipes across all successional stages. This suggests a close mutualistic relationship derived from adaptive processes and local specializations throughout the distribution of both taxa, as supported by the geographic mosaic theory of coevolution.

Ground Spider Guilds and Functional Diversity in Native Pine Woodlands and Eucalyptus Plantations.

Vegetation structure and floristics have a strong influence on the relative abundance of spider guilds and functional diversity of terrestrial arthropods. Human activities have transformed much of the temperate woodlands. The aim of this study was to test five predictions related to the guild distribution and functional diversity of the ground spider communities of Eucalyptus plantations and native pine woodlands in western Mexico. Spiders were collected every fortnight from September to November from 15 pitfalls positioned in each of the eight sites. We also assessed the cover of grasses, herbs, shrubs, and leaf litter in each site. We found that the abundances of ground hunters and sheet weavers between plantations and pine woodlands were different. Nevertheless, there was not a consistent difference between sites of each of the vegetation types. Most species of ground hunters, sheet web weavers, and many other hunters were associated with litter and the grass cover. Nonetheless, in some cases, species of different families belonging to the same guild responded to different variables. Wolf spiders were related to the grass Aristida stricta Micheaux, 1803, while the species of the other families of ground hunters were associated with leaf litter. One Eucalyptus plantation and one pine woodland had the highest functional diversity of all sites. These sites have a well developed litter and grass cover. Our study suggests that the abundance of litter and a high cover of grasses explain the occurrence of species with different traits, and these habitat components results in a high functional diversity.

Distribution of Peucetia viridans (Araneae: Oxyopidae) on Croton ciliatoglandulifer.

Peucetia viridans (Hentz) lives almost exclusively on Croton ciliatoglandulifer (Ortega) in the dry forests of western Mexico. This spider is usually found on pubescent shrubs. Within their host plants, P. viridans has been associated with plant height and cover, as well as with number of flowers or inflorescences in anthesis. Flowers can be used as cues of good habitat conditions or because they attract prey detected by the spider. In this study, we assessed the importance of flowers, plant cover, and plant exposure (sun/shade) on the spider distribution in five 50-plant transects. In a field experiment, we also compared the number of spiders between controls, plants from which inflorescences were removed, and plants with artificial inflorescences. The results from the transects indicate that, when the number of flowers per spider is high, spiders were more abundant in exposed locations, which presumably offer better microclimatic conditions; when flowers become scarce, food may be more difficult to find and the spider distribution become strongly associated with the number of flowers, where they are more likely to find prey. Spider abundances on the experimental plot decreased on plants from which flowers were removed in comparison to control plants. Spider abundance increased on those in which artificial inflorescences were added. The similarity between plants with natural and artificial inflorescences suggests that spiders use flowers as cues of good microhabitats instead of prey visitors, which are significantly less abundant on artificial inflorescences.

The influence of vegetation on bird distribution in dry forests and oak woodlands of western Mexico

The bird species distribution along a dry forest-oak woodland vegetation gradient was studied in autumn and spring in two consecutive years. Intra-seasonal comparisons showed that bird species had similar distributions in each of the two years. Inter-seasonal changes were mainly due to compositional differences even though resident species generally used similar habitats in both seasons. Ordination analyses, based on the first year bird species abundances, showed a clearly segregated distribution between forest and woodland birds. Within these two vegetation types, the distribution tended to be more individualistic. Nevertheless further habitats could be identified according to groups of birds having similar distributions. These habitats did not correspond to the plant associations which resulted from a previous classification of the vegetation. Observations of the plant use by the birds during the study period showed that, in most cases, the plant variables associated with ordination analyses are unlikely to be very important for the bird species life cycles.

Se estudió la distribución de especies de aves a lo largo de un gradiente de vegetación bosque seco – bosque de encino en el otoño y primavera de dos años consecutivos. Las comparaciones intra-estacionales mostraron distribuciones similares de las especies de aves en ambos años. Los cambios inter-estacionales se debieron principalmente a diferencias en la composición, aunque las especies residentes normalmente usan hábitats similares en ambas estaciones. Los análisis de ordenación, basados en las abundancias de las aves en el primer año de muestreo, mostraron una distribución claramente segregada entre aves del bosque seco y del bosque de encino. Aunque la distribución de las especies fue más azarosa dentro de cada tipo de vegetación, se pudieron identificar ciertos hábitats en base a grupos de aves con distribuciones similares. Estos hábitats no correspondieron con las asociaciones vegetales identificadas. Las observaciones del uso de las plantas durante el período de estudio sugieren, en la mayoría de los casos, que las variables vegetales asociadas con los ejes de ordenación no serían muy importantes para el ciclo de vida de las especies de aves. Sin embargo, se requiere investigación adicional para comprender su verdadera función.

The influence of vegetation on bird distribution in dry forests and oak woodlands of western Mexico.

The bird species distribution along a dry forest-oak woodland vegetation gradient was studied in autumn and spring in two consecutive years. Intra-seasonal comparisons showed that bird species had similar distributions in each of the two years. Inter-seasonal changes were mainly due to compositional differences even though resident species generally used similar habitats in both seasons. Ordination analyses, based on the first year bird species abundances, showed a clearly segregated distribution between forest and woodland birds. Within these two vegetation types, the distribution tended to be more individualistic. Nevertheless further habitats could be identified according to groups of birds having similar distributions. These habitats did not correspond to the plant associations which resulted from a previous classification of the vegetation. Observations of the plant use by the birds during the study period showed that, in most cases, the plant variables associated with ordination analyses are unlikely to be very important for the bird species life cycles.

Inductores de la ovulación, su estado actual y experiencia institucional / Ovulation inductors, present state and instutional experience

Antecedentes. La anovulación o esterilidad por factor endócrino ovárico representa del 20 al 30 por ciento de todas las parejas estériles y aunque en la actualidad existen diversos fármacos capaces de inducir ovulación , siguen siendo el citrato de clomifeno y las gonadotropinas menopáusicas humanas los medicamentos de primera línea para el tratamiento de la esterilidad por factor anovulatorio, como hace 30 años que se inició su uso. Objetivo. En el presente trabajo se analiza el marco teórico para la selección de las pacientes candidatas a uno u otro medicamento, así como los esquemas terapéuticos utilizados, efectos secundarios y resultados tanto de ovulación como de embarazos. Método. Se compararon los resultados promedio de la literatura, con la experiencia institucional de los autores. Resultados. Con el citrato de clomifeno en casos bien seleccionados se obtiene ovulación en aproximadamente 80 por ciento de los casos y embarazo en el 40-50 por ciento; en el INPer se obtuvo en un análisis de 200 casos ovulación en el 72 por ciento y embarazo en el 58 por ciento. Con las gonadotropinas menopáusicas humanas los resultados son mas variables encontrando un promedio en la literatura de ovulación del 70 al 90 por ciento y de embarazo del 25 al 55 por ciento. En el INPer de 128 ciclos de tratamiento se obtuvo ovulación el 75.7 por ciento y embarazo en el 36 por ciento de un grupo de 100 mujeres anovulatorias tratadas

Tratamiento de la endometriosis con análogos de GnRH y estudio comparativo / Treatment of endometriosis with GnRH analogues: a comparative study

Objetivo. Evaluar la efectividad del tratamiento de la endometriosis con análogos de GnRH. Material y método. Se estudió a 100 mujeres divididas aleatoriamente en dos grupos: uno tratado con danazol (testigo) y uno con GnRH (experimental). Todas las mujeres contaban con un estudio laparoscópico y al término del tratamiento fueron sometidas a una segunda intervención. Resultados: La remisión de los síntomas y las lesiones endometriósicas fueron similares en ambos grupos, al igual que la tasa de embarazos, con la ventaja de que los efectos secundarios fueron menores en el grupo experimental. Conclusión. Los análogos de GnRH son una buena alternativa en las mujeres con intolerancia al danazol

Adenomiosis y esterilidad / Adenomyosis and sterility

Objetivo. Señalar la presencia de adenomiosis significativa en mujeres nuligestas. Material y método. Se revisaron los archivos del departamento de Patología del INPer entre 1987 y 1994, analizando todas las histerectomías ginecológicas y sus diagnósticos anatomopatológicos. Se estudian los casos de adenomiosis encontrados, seleccionando aquellos con repercusiones clínico-patológicas relevantes. Resultados. Aunque la adenomiosis se relaciona a eventos obstétricos múltiples, se encontraron cinco casos de mujeres nulíparas estériles en la que la severidad de su alteración obligó a efectuarles histerectomía. Se enfatiza la necesidad de establecer diagnóstico de adenomiosis, recurriendo a procedimientos auxiliares. Se plantea en las pacientes que deseen embarazarse, la utilidad del uso de agonistas GnRH como modalidad terapéutica útil