This study highlights the importance of quantifying groundwater resources for the Monahans and Kermit dune fields in the northern Chihuahua Desert, West Texas USA as potential contributors to the regional Pecos Valley Aquifer (PVA). Sedimentary architecture models of these dune fields show perched aquifers with water tables 1-10m below the surface and southwestward groundwater flow sub-parallel to a Pleistocene/Pliocene aquitard. Sinkhole-like features into the top of the aquitard are infilled with the thickest occurrences of aeolian sand. Groundwater recharge occurs from the enhanced capture of precipitation on mostly bare active dunes where infiltration rates >250mm/hr. The deuterium and oxygen isotopic ratios for groundwater from the Kermit and Monahans dune fields show pronounced evaporative isotopic depletion and less isotopic variability than corresponding rainfall, particularly for deuterium values. Groundwater from a shallow central well in the Kermit dune field yielded contemporary 14C activity (Fm =1.02), indicating contributions from recent precipitation. In contrast, more evolved 14C values at the western margin (FM=0.84) and at 30m below the surface (FM=0.76), similar to proximal Fm values from the PVA (0.89-0.82), may indicate dissolution of older (> 100 ka) DIC from buried playa-lake sediments and carbonate-soils with groundwater flux to the southwest, and less direct atmospheric influence. The perched aquifers of the Monahans and Kermit dune fields contain water volumes > 0.1 km3 and may contribute up to 9% of the total annual recharge to the PVA.

Conifer bark beetles (Coleoptera: Curculionidae: Scolytinae) are major agents of natural disturbance in temperate forests of the northern hemisphere, capable of killing billions of trees in native forests. The dynamics of these insect populations are influenced by climatic variability. To understand such a relationship, it is necessary to monitor the population fluctuation of the species present over time. In this regard, the objective of the present study was to determine the species community of the genus Dendroctonus, the population fluctuation throughout the months of the year, and the effects of relative humidity, temperature, and precipitation on the fluctuation, at three sites of mixed forests in the Municipality of Bocoyna, Chihuahua, in northern Mexico. For insect monitoring, we used Lindgren funnel traps (with 8 funnels each) baited with semiochemicals. Every two weeks, and during 2 years, we collected, identified, and counted the insects. The identification of the species was based on the external morphology and characteristics of the male seminal rod. Temperature and relative humidity were measured using climate data loggers (HOBOs). We found six Dendroctonus species. We also determined the population fluctuation patterns of D. mexicanus Hopkins, D. frontalis Zimmermann, and D. brevicomis LeConte, species with the highest number of captures at each site. Additionally, the relationship between species abundance and climatic variables was determined. The variable that significantly influenced (P<0.05) abundance was temperature. Relative humidity and precipitation variables did not show a significant relationship (P>0.05).