Laura Macario-González

Background: Soil invertebrates play an active role as ecosystem engineers in physical, chemical, and biological processes, and are therefore important bioindicators of the health of natural and agroecosystems, such as pastoral landscapes, where these organisms have been poorly studied. Objectives: To evaluate the abundance, richness, and diversity of soil invertebrates and their importance as bioindicators in a livestock agroforestry landscape in southeastern Mexico. Methods: We used 45 pitfall traps placed in three production units (PU1, PU2 and PU3). Each PU’s maintain similarly grazing areas, with grass monocultures and dispersed native trees, and natural vegetation patches within the same area. Sampling was performed across three periods (the dry season, the transition between the dry and rainy seasons, and the rainy season) to account for seasonal variation. Results: We obtained a total abundance of 12,342 invertebrates and a richness of 26 orders (taxa). The most abundant taxa were Hymenoptera (52 %), Coleoptera (15 %), Diptera (11 %), and Orthoptera (5%), and the remaining 17 % corresponded to 22 taxa. Taxon diversity was higher in PU3 compared to the other production units. Implications: Maintaining a livestock landscape with habitat heterogeneity can contribute to the conservation of biodiversity and the sustainability of production systems. Conclusions: The presence of indicator taxa was heterogeneous among the production units, which shows that, at the livestock agroforestry landscape scale, are able to maintain a functional structure that preserves the ecosystem services provided by the diversity of soil invertebrates.

In this study, we examined ostracode biodiversity and species taxonomy, based on morphological characteristics, from the sulfate-bicarbonate rich, oligotrophic, and freshwater Bacalar hydrological system. A total of 19 species belonging to five subfamilies were identified. Here, we describe five new species: Cypris nicte Macario-González & Cohuo sp. nov., Pseudocandona tzabek Macario-González & Cohuo sp. nov., Thalassocypria zazilha Macario-González & Cohuo sp. nov., Dolerocypria maanik Macario-González & Cohuo sp. nov., and Cyprideis ichkabal Macario-González & Cohuo sp. nov. These species are clearly distinguished from their congeners by valve outline, overall shape, or appendages morphology, particularly the male sexual appendages. Thalassocypria Hartmann, 1957, Dolerocypria Tressler, 1937, Perissocythere Stephenson, 1938, and Cyprideis Jones, 1857 are distributed worldwide only in estuarine, anchialine, and marine environments. However, their continued presence in the Bacalar system at sporadically sampling for a decade suggests that the species have successfully colonized, naturalized to freshwater, and becoming established residents, likely supported by the carbonate-related high conductivity waters. We discuss the hypothetical mechanisms underlying their inland colonization and highlight the relevance of Bacalar system as a potential ecological niche supporting their freshwater establishment and distribution.

La Reserva de la Biosfera Sierra la Laguna (RBSL) en Baja California Sur, es una zona de almacenamiento natural de agua, que recarga los mantos acuíferos que abastecen a las ciudades de la Paz y Los Cabos. Sin embargo, en los últimos años los acuíferos en esta región han sido objeto de sobrexplotación y depósito de desechos, que ha conducido a un incremento de nutrientes y contaminantes provenientes principalmente de actividades ganaderas e industriales. No obstante, se desconoce el estado actual de salud de los ambientes acuáticos en la RBSL. En este trabajo, se evaluó la calidad de agua de once y dieciocho sistemas durante las temporadas cálido/seco y frío/húmedo del año 2023 respectivamente, de la Región Hidrológica Prioritaria, Reserva de la Biosfera Sierra La laguna y oasis aledaños. La finalidad de este trabajo fue determinar la calidad del agua en estos ecosistemas acuáticos y obtener datos que sirvan como base para futuros programas de monitoreo y conservación del recurso agua.

Urbanization, expanding tourism, and infrastructure development are altering water quality in the Yucatán Peninsula (YP). This study evaluated temporal variations in water quality and trophic status using the Water Quality Index (WQI) and Trophic State Index (TSI) across ten inland water systems (IWS) monitored from 2012 to 2024. Spatial patterns from an additional 29 IWS sampled in 2024 were also analyzed. The Mann–Kendall test and Theil–Sen estimator revealed a significant decline in water quality (Z = −9.07, β = −2.62) and a sustained increase in eutrophication (Z = 4.00, β = 1.15). The NMDS separated two lake groups: one with high nutrients and total coliforms, and another with elevated TDS and conductivity. The PCA identified turbidity, nitrogen, chlorophyll-a, and total coliforms as variables exerting the strongest influence on water variability. The WQI indicated generally poor conditions except in Bacalar Centro and Xul-Ha, which showed fair quality. The highest TSI values occurred in inland systems, except for La Sabana, which exhibited hypereutrophic conditions linked to wastewater inputs. NT–PT ratio indicated nitrogen limitation in most lakes, likely driven by groundwater recharge and low surface runoff. Overall, results demonstrate a progressive decline in water quality and widespread eutrophication across the YP.

Introducción. La pérdida de la vegetación natural para el establecimiento de monocultivos de pastos (MP) para la ganadería disminuye las reservas de carbono (C) y nitrógeno (N) de los suelos. Los sistemas silvopastoriles (SSP) pueden contribuir a revertir este problema, dado que la presencia de leguminosas arbóreas nativas puede incrementar la capacidad de secuestro de C y N en el suelo. Objetivo. Evaluar el almacenamiento de C y N del suelo en sistemas ganaderos con árboles dispersos en potreros (ADP) de Piscidia piscipula, MP y áreas de selva mediana (SM), en sureste de México. Métodos. Se seleccionaron 12 sitios con MP, ADP y SM. En cada sitio se elaboraron tres calicatas de 50×50×50 cm y se tomaron muestras inalteradas de suelo en estratos de 10 cm. Se determinaron las fracciones de C y N del suelo y se estimó su almacenamiento total en los tres sistemas (0-50 cm), en un diseño de bloques completos al azar. Resultados y discusión. Las SM y ADP mostraron los mayores almacenes totales de C (119.1 y 113.3 Mg C/ha) y N del suelo (15.5 y 16.1 Mg N/ha), esto se debe al aporte continuo de materia orgánica de calidad, la cual incrementa las reservas de C (Ribeiro et al., 2023); además, especies como P. piscipula tienen la capacidad de fijar el N al suelo de manera biológica, lo que contribuye a incrementar las reservas de N en el suelo (Cubillos et al., 2016). A diferencia de los MP, donde la usencia de las especies leguminosas ocasiona la oxidación del C y la lixiviación del N (Villanueva-López et al., 2015). Conclusión. A diferencia del MP, los SSP con leguminosas arbóreas nativas representan una alternativa viable para mantener o recuperar los almacenes de C y N del suelo en la ganadería del sureste de México.

The Mexican Caribbean coastal dune is protected by national and international environmental legislation. However, through permits, concessions and authorizations for changes in land use, the coastal dune has been fragmented or suppressed, mainly for touristic activities, causing a decline in protective and ecological ecosystem services. In this study, we evaluated the strength and weakness of Mexican legislation to protect the Caribbean coastal dune ecosystem and estimated the historical and current effects on coastal dune vegetation and dune geomorphology, associated with legal allowances of land use change in the Sian Ka’an Biosphere Reserve (SKBR). Legislation at the federal, state and local level were critically reviewed, and with remote sensing techniques and the Remotely Piloted Aircraft System (RPAS), we conducted a case study in the SKBR to estimate coastal dune vegetation alteration trends during the period 2011–2020 and modifications on the dune geomorphology associated with land use change allowances. At the federal (four laws), state (eight laws) and local (nine Local and Territorial Planning Programs (POEL and POET) levels, we found a lack of consensus and alignment between regulations, starting with a lack of definition of ecosystems subject to protection. For coastal dunes, none of them consider topography, ecological function and a way to identify it in the field, making the surveillance highly complex and favoring land use changes, the removal of vegetation and dune geomorphology alteration. Remote sensing techniques showed that areas with land use authorizations exhibit negative vegetation cover trends (Mann–Kendall <−0.4), indicating a decline in vegetation cover density that is mostly anthropogenically induced. The RPAS analysis demonstrated drastic alterations to complete elimination of the coastal dune geomorphology in areas with land use change. In the Mexican Caribbean, the loss of coastal dune and associated ecosystem by the lack of congruent legislation threatens the environmental stability of the coastal areas.

In the Mexican Caribbean, environmental changes, hydrometeorological events, and anthropogenic activities promote dynamism in the coastal vegetation cover associated with the dune; however, their pace and magnitude remain uncertain. Using Landsat 7 imagery, spatial and temporal changes in coastal dune vegetation were estimated for the 2011–2020 period in the Sian Ka’an Biosphere Reserve. The SAVI index revealed cover changes at different magnitudes and paces at the biannual, seasonal, and monthly timeframes. Climatic seasons had a significant influence on vegetation cover, with increases in cover during northerlies (SAVI: p = 0.000), while the topographic profile of the dune was relevant for structure. Distance-based multiple regressions and redundancy analysis showed that temperature had a significant effect (p < 0.05) on SAVI patterns, whereas precipitation showed little influence (p > 0.05). The Mann–Kendall tendency test indicated high dynamism in vegetation loss and recovery with no defined patterns, mostly associated with anthropogenic disturbance. High-density vegetation such as mangroves, palm trees, and shrubs was the most drastically affected, although a reduction in bare soil was also recorded. This study demonstrated that hydrometeorological events and climate variability in the long term have little influence on vegetation dynamism. Lastly, it was observed that anthropogenic activities promoted vegetation loss and transitions; however, the latter were also linked to recoveries in areas with pristine environments, relevant for tourism.