Julio C Canales-Delgadillo

Anthropogenic salinization impacts the health of aquatic and terrestrial ecosystems
worldwide. In tropical and subtropical areas, shrimp farm aquaculture uses water
from adjacent ecosystems to fill the culture ponds, where enhanced evaporation
cause salinization of discharged water. In this study, we studied water salinity
before and after shrimp farm harvest and implemented a three-dimensional
hydrodynamic model to assess the impact on a subtropical coastal lagoon that
receives water releases from shrimp ponds. The shrimp pond discharge
significantly increased the salinity of receiving waters, at least 3 psu over the local
variation. In the worst-case salinization scenario, when harvest occurs after a long
dry season, salinity could increase by up to 6 psu. The induced salinization due to
shrimp pond effluents remained up to 2 tidal cycles after harvest, and could affect
biota. The methodology and results of this study can be used to assess the
impacts of shrimp aquaculture worldwide.

Background. Mangrove forests provide many ecosystem services, including the provision of habitat that supports avian biodiversity. However, hurricanes can knock down trees, alter hydrologic connectivity, and affect avian habitat. In 1995, Hurricanes Opal and Roxanne destroyed approximately 1,700 ha of mangrove forest in Laguna de Términos, Mexico. Since then, hydrological restoration has been implemented to protect the mangrove forest and its biodiversity. Methods. Since avian communities are often considered biological indicators of ecosystem quality, avian diversity and species relative abundance were evaluated as indicators of mangrove restoration success by comparing undisturbed mangrove patches with those affected by the hurricanes. Using bird surveys, similarity analyses, and generalized linear models, we evaluated the effects of water quality variables and forest structure on the relative abundance and diversity of the avian community in disturbed, restored, and undisturbed mangrove patches. Results. Higher bird species richness and relative abundances were found in disturbed and restored sites compared to the undisturbed site. After restoration, values of frequency of flooding, water temperature, tree density, and the number of tree species were more similar to that of the undisturbed site than to the values of the disturbed one. Such variables influenced the relative abundance of bird guilds in the different habitat conditions. Furthermore, some insectivorous bird species, such as the Yellow Warbler and Tropical Kingbird, were found to be similarly abundant in both undisturbed and restored sites, but absent or very low in occurrence at the disturbed site. Conclusions. Collectively, our results strongly suggest that hydrologic restoration helps to enhance niche availability for different bird guilds, including water and canopy bird species. Our work can help inform management strategies that benefit avian communities in mangrove forests and wetland systems.

The mangroves of Laguna de Términos, Campeche have been affected by the loss of hydrological connection due to tropical storms and
hurricanes. The objective of this study was to evaluate the natural regeneration in a degraded area, after having implemented actions of
restoration through hydrological restoration. Three sampling sites with different times of restoration (1-3 years), and a preserved natural
mangrove site as reference, were established. The sampling was carried out in the years 2014 to 2015. Forest structure (density, height),
survival, growth rate of seedlings and environmental characteristics were measured. The relationship between the vegetation and
environmental characteristics was determined using simple linear regressions and multidimensional scaling analysis. To determine the
dispersal of seedlings, a mixed linear model of the seedling density vs distance vs time of restoration was generated. The results showed
that distance to natural mangroves affects the seedling density. The phosphates concentration is related to survival, while the ammonia
and sulfide concentration is negatively related to seedling density. The actions of hydrological restoration influenced the settlement and
growth seedling of mangrove vegetation, therefore natural areas of mangroves and the water reconnection facilitated propagule dispersal
towards the degraded areas, highlighting the importance of the inclusion of natural areas within the restoration projects.

Resumen Antecedentes: Cambios en los patrones hidrológicos degradan la estructura forestal y afectan la producti-vidad primaria. Con acciones de restauración hidrológica, se pretende restablecer condiciones biogeoquí-micas para facilitar el establecimiento, sobrevivencia y crecimiento de la vegetación del manglar que permitan la recuperación de la estructura forestal y la productividad de raíces subterráneas (< 20 mm). Pregunta: ¿Pueden los cambios ambientales inducidos por la restauración hidrológica reactivar la pro-ductividad de raíces? Especie en estudio: Los cambios en biomasa y productividad de raíces subterráneas de Avicennia germi-nans fueron usadas como indicador de éxito de la restauración. Sitio de estudio y fechas: Isla del Carmen, Laguna de Términos, Campeche, agosto de 2013 a febrero de 2015. Métodos: Se seleccionaron tres sitios de manglar en restauración y uno natural como referencia. En ellos se evaluó la concentración de algunos nutrientes (nitratos, nitritos, amonio y fosfatos) y reguladores como la salinidad y el hidroperíodo. Se evaluó entre sitios la biomasa y productividad de raíces en núcleos de crecimiento enterrados a 30 cm de profundidad durante 18 meses. Resultados: La productividad de raíces < 20 mm de diámetro fue menor en los sitios en restauración (17 a 233 g m 2 año-1) que en el sitio de referencia (414 g m 2 año-1). La productividad de raíces estuvo asociada con la estructura forestal y las condiciones hidrológicas. Conclusiones: La proporción de raíces > 2 mm de diámetro fue mayor en el sitio de referencia y decreció hacia los sitios restaurados, indicando que la estructura forestal (regeneración natural) y el tiempo (años) después de la restauración fue importante para la recuperación funcional del ecosistema de manglar. Palabras clave: biogeoquímica, hidroperíodo, producción subterránea, raíces finas, rehabilitación hidro-lógica. Abstract Background: Changes in hydrological patterns produce degradation that affects forest structure and primary productivity. With actions of hydrological restoration, it is intended to restore biogeochemical conditions to facilitate the establishment, survival and growth of mangrove vegetation to recovering the forest structure and the productivity of underground roots (< 20 mm). Research question: Inducing changes in environmental variables through hydrological restoration reactivate the process of roots production? Study species: Biomass and fine roots production of Avicennia germinans were used as indicators of restoration success. Study sites and dates: This study was carried out from August 2013 to February 2015 in Isla del Carmen, located in Terminos Lagoon, Campeche. Methods: The study included four sampling sites, three of which were sites restored at different times. The fourth one was a natural undisturbed mangrove patch used as a reference for comparisons. After incubation of about 18 months within buried growth cores in each study site, biomass and roots production were quantified and contrasted. Results: The restored sites showed a lower root production (< 20 mm) (17 to 233 g m 2 yr-1) regard to the reference site (414 g m 2 yr-1). The analyses showed that production is determined by the forestry structure and hydrological conditions. Conclusion: The proportion of roots > 2 mm in diameter was greater in the reference site and decreased towards the restored sites, indicating that the forest structure (natural regeneration) and the time (years) after the restoration was important for the functional recovery of the mangrove ecosystem.

The restoration of mangroves has gained prominence in recent decades. Hydrological rehabilitation has been undertaken to connect impaired mangroves with the sea, lagoons or estuaries. Because mangrove hydrodynamics occurs on the surface and interstitial spaces in the sediment, we propose to determine the hydrological flow paths to restore the hydrological regimes of the impaired mangroves. The hydrological flow paths were determined through a micro basin analysis based on microtopographic data to generate a digital elevation model. Applying this methodological approach, the hydrology of an impaired area on a barrier island in the Gulf of Mexico was restored by excavating, desilting or clearing the channels on the identified hydrological flow paths. This area was compared to one in which impaired mangroves were reconnected to the marine lagoon but disregarding the flow paths. Data collected in both areas were evaluated by flood level analysis, using two methods: (i) a simple linear regression model (SLRM) and (ii) spectral analysis (SA), also known as dominant frequency analysis. The results suggest that restoration based on the hydrological flow paths was more effective than the direct opening to the nearest main water body without accounting for the microtopography. In both areas, soil salinity and sulfides decreased after hydrological reconnection. However, a greater efficiency in the investment of time and human resources was achieved when preferential flow paths were identified and taken into account. The methodological procedures described in this study are of universal application to other mangrove restoration programs.

Information deficit constrains our capacity to assess the status of threatened species in regional and
global contexts. In this study of the endangered Worthen’s Sparrow Spizella wortheni, we first
review its current and potential distribution using the species distribution software, Maxent.
An initial basic model was constructed using historical records, and used to guide a subsequent
search for additional populations in summer 2013. Using the information gathered from our survey,
we built a second, breeding model, to update the current and potential species distribution. Population
size was estimated using line transects of variable length to count singing males and calculate densities per 10 ha. We found 10 new small reproductive populations dispersed south of the established
core area, increasing the extent of occurrence of the species from 25 km2 to almost 17,000 km2.
Suitable habitat across the species’ range was more than threefold higher in the breeding compared with the basic model. We counted 316 males, with a mean density of four individuals per 10 ha.
Our results demonstrate that conservation assessment based on limited records can exaggerate
the vulnerability of species, and confirm that the Worthen’s Sparrow population and geographic
distribution range are larger than previously determined, indicating that the Red List status of
this species should be reconsidered. The use of niche models was successful in enhancing species
information data quantity (e.g. range extensions) and quality (e.g. more precise habitat requirements),
facilitating improved understanding of needs and conservation status in the wild.

Charadrius montanus nests mainly inthe desert grassland of western United States of America and spend the winter at the north of Mexico.The aim of this research was to monitoring Charadrius montanus populations in El Tokio Region, located at northeastern Mexico territory. Counts of Charadrius mintanus were made on line transects during summer and winter season from 2003 to 2006 at eight sites in the states of Coahuila, Nuevo Leon and San Luis Potosi, at least once during each season.Density and population size were calculated for each sampling site. Estimations were carried out with the software Distance Beta 5.0. Bird annual desnsity was significantly different across the years of the study (Kruskal-Wallis test H = 41.13, d.f. = 3, p &lt; 0.001), and among sites (F = 2.647, d.f. = 7, p &lt;00.001). Estimated winter and summer population size in EL Tokio represents around 8% and 3% - 6% of the total pupulation size of the species respectively. Breeding activity of Charadrius montanu...

Mexico has a unique biodiversity that places it within the list of megadiverse countries; it has three of the 34 ecoregions of the world and sites that are considered wilderness areas worldwide. The use of Genomics as a tool for research in Mexico began in the late 1930s with work aimed at the genetic improvement of commercial crops and to understand the ecological foundations of the genetic variation in Drosohpila pseudooscura, however, it wasn’t until the decades of 1980-1990s that these tools were used for the study of natural populations of flora and fauna with purposes of conservation and management. Nonetheless, the potential that
genomic tools have to improve the strategies and policies of management to ensure food production and conservation of
wildlife in Mexico, these have not been widely applied. In this paper the areas of knowledge in wildlife where genomics have
been applied in the study of natural populations of flora and fauna in Mexico were reviewed, and the practical applications of genomics for management and conservation of species of biological and commercial concern were discussed.

Charadrius montanus nests, mainly, in the desert grassland of western United States of America and spend the winter at the north of Mexico. The aim of this research was to monitor their populations in the El Tokio region, located at the northeast of the Mexican territory. A counting of all individuals was made during the summers and winters from 2003 a 2006 in eight sites, in the states of Coahuila, Nuevo León and San Luis Potosí, at least once during each season. The number and length of transects were determined from the size of the colony to be assessed. Density and population size were calculated for each sampling. The estimations were made with the Distance Beta 5.0 program Bird annual density was significantly different in the years of study (Kruskal-Wallis ANOVA, H = 41.13, P < 0.0001), and that of birds varied significantly among sites (F = 2.647; P = 0.0007). During winter, the density in the La Soledad, NL, was significantly higher (t 0.05, 3= 4.235, p = 0.024) than that recorded in the other localities; and in this time of the year it was greater than that estimated for summer, which reflects that the migratory populations mix with the residents. However, it is still unknown if the summer birds remain in the area during the cold time. The estimated winter population represents around 8 % of the total number of birds of the species, while that of fall adds 3 to 6 percent to it.

Habitat loss and fragmentation is one of the main causes of biodiversity loss. Rare species are generally thought to be more
sensitive to habitat fragmentation than common ones as small populations become even smaller. We did a population genetic study on a rare bird, the Worthen ’ s sparrow Spizella wortheni which is endemic to semi-arid and arid regions of northeast Mexico. Its population numbers suffer greatly from the transformation of grassland into farmland that leads to a patchy distribution with locally small population sizes. Our data show that its genetic diversity is nevertheless high, few to no differentiation between study localities was found, and gene flow was high. Although we can not exclude that is too early to see an impact on the genetic level, we think that these results might be explained by the species ’ biology: like many other birds living in arid areas, the Worthen ’ s sparrow has a nomadic life style; depending on local conditions individuals flexibly move between areas. This behavior could enhance their ability to find suitable habitat patches in a fragmented landscape. Our results imply that nomadic behavior, which is an adaptation to high temporal variability in environmental conditions, may make species more resilient to spatial variability caused by habitat fragmentation. This insight contributes to identifying common factors such as nomadism that predict a species ’ sensitivity to habitat fragmentation.

We report the isolation and characterization of nine microsatellite markers from Worthen’s Sparrow (Spizella wortheni), an endangered bird species endemic to northeastern Mexico. We tested the markers in 32 samples of the species collected near Saltillo Coahuila, Mexico. All markers were polymorphic, with 3–31 alleles per locus, and no difference was found between the observed and expected heterozygosity when applying a sequential Bonferroni correction and a table-wide significance level of 0.05. We found no evidence for linkage disequilibrium between the markers and estimated a null allele frequency of 0.00–0.05. The new markers will allow elucidating the genetic structure and life history of Worthen’s Sparrow and guiding conservation efforts for this endangered species.