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Published accounts of the Common Pauraque (Nyctidromus albicollis) on Isla Cozumel, Quintana Roo, Mexico, date back at least 72 years, yet there exists no evidence in the literature of the species breeding on the island. Here we report the first scientific descriptions of nesting by Common Pauraque on Cozumel. During fieldwork in 2008 and 2009, we opportunistically documented 9 nests, including 4 with eggs and 5 with chicks. Clutch size for all nests with eggs was 2 whereas nests observed with young consisted of 1 (N= 3) or 2 (N= 2) nestlings. To complement our observations, we searched available citizen science data and discovered one additional record of nesting in early June 2017 and a possible second nest in late May 2018. Collectively, these observations indicate that Common Pauraque breeds on Cozumel from at least mid-May into July. However, surveys throughout the year are required to determine whether the population on Cozumel breeds seasonally, breeds year-round, or has a more complex breeding phenology. Additional work is especially needed given that we observed some of the active nests during one of Cozumel's wettest months (June) and previous work has hypothesized that caprimulgids generally are more restricted to nesting at drier times of the year. [ABSTRACT FROM AUTHOR]

Fish communities of tropical lakes are commonly predicted by local environmental variables, including depth, temperature, oxygen concentration, and substrate composition. Increasingly, however, lacustrine fish communities are being impacted by invasive species. In the state of Quintana Roo, on the Caribbean versant of the Yucatan Peninsula in Mexico, inland aquaculture production has resulted in the widespread establishment of African tilapia (Oreochromis sp.). However, there are still limited quantitative data on their abundance relative to indigenous species, or their influence on native fish diversity. Here, we quantified the ichthyofauna of six lakes from this region, alongside physical and chemical environmental variables. Overall, we observed that greater dissolved oxygen concentration and shallower depths were associated with the highest fish biodiversity across lakes. Moreover, spatial comparisons additionally highlighted the importance of substrate heterogeneity and lake area as influential in determining native fish community structure. Notably, in all lakes, tilapia were relatively uncommon, comprising less than 3% of all fish captured, and their presence was not a significant predictor of indigenous fish biodiversity. Based on these results, we suggest that tilapia may have strong limitations on their population size, plausibly due to the presence of predatory native fish species, or scarce suitable ecological resources (food, breeding habitat). Conservation-focussed lake-wide management of native species via protection of core habitat characteristics may be key to promoting environmental resistance against negative effects of tilapia regional expansions. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper explores strong indirect evidence for existence of a previously unrecognized deep groundwater aquifer in southern Quintana Roo, adjacent parts of Campeche, and (probably) northern Belize. The region contains rocks of Cretaceous-to-Holocene age, including: 1) an up-thrust block of the late Cretaceous carbonate known in Belize as the Barton Creek Formation, which is the oldest formation exposed in the Mexican Yucatán Peninsula, 2) the Cretaceous/Paleogene Albion Formation consisting of weakly consolidated Chicxulub impact air-fall deposits, 3) the Paleocene-Eocene Icaiche Formation, containing a massive 25-35 m thick gypsum member that crops out over an estimated area of more than 10,000 km2 in the elevated interior region of the northern lowlands, and 4) younger rocks of relatively low permeability that flank the region on the east. Hydrogeology is dominated by groundwater and surface flow in and adjacent to the Rio Hondo Fault Zone (RHFZ) and by recharge in the elevated interior region. Groundwater in the elevated region has a high sulfate concentration and is approximately saturated with gypsum dissolved from the Icaiche Formation. High-sulfate groundwater and river water with a slightly lower gypsum saturation index than in the elevated region also occurs in the RHFZ, but no water of comparably high sulfate content is present elsewhere in the study area. This suggests that the elevated region is a recharge zone for high-sulfate groundwater carried eastward beneath a 50 km gap by a deep, previously unrecognized aquifer and then discharged into the RHFZ. Based on chemistry of chloride, sulfate and other ions it is proposed here that a deep aquifer comprising the strongly weathered upper surface of the Barton Creek Formation plus the overlying weakly consolidated Albion Formation connects the elevated recharge area with the RHFZ discharge area. If this composite permeable zone does extend westward beneath the elevated recharge zone, it is probably an excellent aquifer. [ABSTRACT FROM AUTHOR]

Sudden drainage of Lake Chakanbacán (also known as Om or Chakambacab) occurred naturally and without warning between 19 and 21 August, 2018. Lake Chakanbacán, located in southern Quintana Roo, 16.5 Km WNW of Nicolás Bravo, Quintana Roo is part of the western edge of the composite Morocoy-Nuevo Becak polje. Slumping associated with lake drainage has opened up fractures on the west bank of the lake, exposing gypsum of the Icaiche Formation. This occurrence establishes the western lake bank as the easternmost known outcrop of Icaiche gypsum in the area. Drainage of Lake Chakanbacán appears to be part of a karst process that proceeds by rapid dissolution and selective removal of layers of gypsum of the Icaiche Formation beneath the lake bed. Thus, the August 2018 lake drainage may demonstrate, in real-time, an ongoing weathering process responsible for a major regional geomorphic feature: the numerous internally drained karst depressions (poljes) up to >100km long in Campeche and southern Quintana Roo. It has been proposed that these poljes are collapse features resulting from removal in solution of gypsum of the Icaiche Formation. They occur both within and adjacent to a large area where the Icaiche Formation crops out, and, notably, over an estimated 10000 km2 or more within that formation where massive beds of gypsum are present on the surface or beneath a thin protective cap of rock resistant to chemical weathering. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cadmium is a toxic metal for zooplankton that produces deformations. It is also considered an environmental hazard to aquatic life. Since it has a significant effect in some marine organisms, we used two native zooplankton species from Quintana Roo, Mexico to obtain data regarding cadmium toxicity including the threshold concentration for observable morphological alterations and the percentage of organisms with morphological alterations at the exposure concentrations. We used the rotifer Philodina cf roseola and the oligochaeta Aeolosoma hemprichi, since both feed from the algae Nannochloropsis oculata. Both animals were exposed to a cadmium concentration range from 0.05 mg/l (0.047 mg/l, real concentration) to 10.0 mg/l (9.39 mg/l, real concentration) for 24 h. The LC50 for cadmium in P. cf roseola was 0.7 mg/l (0.65 mg/l, real concentration), whereas in A. hemprichi was 3.38 mg/l (3.17 mg/l, real concentration). The exposure of cadmium at 0.5 mg/l (0.47 mg/l, real concentration) for less than 24 h induced morphological alterations in the lorica of rotifers, foot deformations, and constriction in the middle part of the body. In oligochaetes, damage to the epidermis was noted. The threshold concentration where deformations appeared in rotifer was 0.3 mg/l at 24 h, while in oligochaeta was 0.5 mg/l (0.47 mg/l, real concentration) at 30 min. We concluded that cadmium promotes alterations in aquatic organisms due to direct exposure added to the culture medium. [ABSTRACT FROM AUTHOR]

Microanalysis of elemental composition using dispersive energy X-ray is a biomonitoring tool to identify hazard metals. Using scanning electron microscopy/energy dispersive X-ray spectrometry, we studied the bioaccumulation of toxic metals in the lorica of diatoms, dinoflagellates, rotifers, cladocerans, copepods and fish scales in the aquatic ecosystems of northeastern Quintana Roo, Mexico. The study was carried out in the coastal zone, where samples were collected in 16 exposed bodies of water, including dolines, mangroves and lagoons. Microanalysis of the most abundant organisms revealed evidence of the presence of essential trace elements and metals (Ag, Al, Br, Cd, Cu, Fe, Hg, Pb and Zn) in the lorica and scales. Furthermore, interpolation maps of the northeastern zone of Quintana Roo were produced to pinpoint critical pollution zones of Cd, Hg and Pb, elements that are deemed toxic to the health of humans and aquatic ecosystems. In conclusion, elemental microanalysis of species native to the Mexican state of Quintana Roo using X-ray is a powerful tool for aquatic and toxicological biomonitoring of hazardous metals. [ABSTRACT FROM AUTHOR]

The Paleogene-Eocene Icaiche Formation, which contains bedded gypsum deposits that cover an estimated minimum area of 10000 km2, is located in the southern parts of the Mexican states Yucatan, Campeche and Quintana Roo. The formation has been little studied because it crops out in an area with limited access, few people, and little economic activity. Low population density is a consequence of the sulfate-contaminated water that is produced during weathering and dissolution of the gypsum deposits in the formation. The Icaiche Formation occupies a considerable part of the physiographic area known as the Elevated Interior Region (EIR) of the Yucatán Peninsula, which encompasses a terrain that the Maya occupied with varying success for almost two millennia and finally almost completely abandoned by about 950 CE. During their tenure, the Maya survived and at times prospered in this region of unpalatable groundwater by using and adapting natural depressions (called bajos) for water supply and, somewhat later, by using abundant impermeable local clays in construction of dams and ingenious systems for water storage and transport. Because of the relatively high solubility of gypsum, the Icaiche Formation has had an outsize influence on hydrologic and geomorphic features and groundwater geochemistry beyond where it crops out and into parts of the Yucatán Peninsula where it is present in the subsurface, particularly those places where it encounters flowing groundwater. In this study, we propose that gypsum dissolution, followed by collapse of overlying rock, was important in: 1) the formation of poljes (large, partly or completely enclosed karst basins with flat floors and interior drainage) along the east and west margins of the EIR; 2) the development of deep karst in north central Yucatán state; and 3) the formation of irregular terrains, extensive brecciation of rock, and highly varying water quality in the area at the eastern margin of the EIR (between Lake Chichancanab and Felipe Carrillo Puerto, Quintana Roo). Argillaceous sediment released during weathering of the Icaiche Formation, perhaps mixed with siliceous components of impact deposits from the Chicxulub Impact may have affected the permeability of post-Eocene marine sedimentary rocks, perhaps including local facies of the Carrillo Puerto Formation, formed on the southeast margin of the Peninsula. The resulting rocks have markedly lower permeability than rocks of the more northerly lowlands of the Mexican portion of the Yucatán Peninsula that host a pervasive fresh water lens overlying a saline intrusion. [ABSTRACT FROM AUTHOR]

Copyright of Agro Productividad is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We studied succession over five years in a seasonally dry tropical forest in Quintana Roo, Mexico, following three different types of experimental disturbance (slashing and complete felling; slashing, felling and burning; and machine-clearing), each one implemented in 1996 on two 0.5 ha treatment plots. Before experimental disturbances, the floristic composition, dominance and diversity of the forest vegetation had been determined. In 1997, after treatments were applied, a second survey characterized early secondary vegetation at one year. A third survey was conducted in 2001. The 1996 vegetation composition revealed no significant differences among the six treatment plots. In 1997, floristic composition on the six treatment plots showed differences in dominance and diversity: the post-treatment vegetation on the slash/fell treatment was clearly distinct from that on the other two treatments. In 2001, differences among the plots had decreased considerably. Comparisons among seral stages revealed that one-year-old secondary vegetation differed from the pre-disturbance original vegetation, while five-year-old vegetation was similar to the original in its diversity, floristic composition and dominance. Felling alone favors species with a high resprouting capacity. The frequency of species with resprouting capacity was lower on slash/fell/burn treatments and lowest on machine-cleared plots. Results indicate that the effect of disturbance tends to decline over time and that complete clearing of small areas is effective as a silvicultural treatment to favor regeneration of valuable timber species and sustain diversity. [ABSTRACT FROM AUTHOR]

Abstract: Pollen analysis and oxygen isotope measurements on a sediment core recovered from Lake Tzib, revealed the vegetation and climate history of central Quintana Roo, southeast Mexico for the last ∼7900calyr. During the early Holocene (7900–7000calyr BP), vegetation changed from medium- and low-stature forest with nearby mangroves, to medium-stature forest. Between 6500 and 4700calyr BP, climate proxies indicate a transition from relatively moist to drier environmental conditions. Around 3500calyr BP, even drier conditions prevailed. These dry conditions correspond to the onset of dry phases identified elsewhere in Mexico and Central America. An inferred dry event at 1200calyr BP is correlated temporally with dry conditions inferred from a marine core taken in the Cariaco Basin, north of Venezuela. The dry episode falls within the ancient Maya Terminal Classic archaeological period. We found evidence for strong forest disturbance during that period. Around 700calyr BP (1200AD), sediment variables indicate moister environmental conditions that fall within the period of the medieval climate optimum. [Copyright &y& Elsevier]

A palygorskite unit was discovered in a road cut of undifferentiated Tertiary limestone between the villages of El Pariso and San Roman (18°49.309N, 88°37.861W) in the southeastern Yucatán Peninsula, Mexico. This is the southern most locality of a clay-rich sedimentary unit reported in the literature for the Tertiary carbonates of the Yucatán Peninsula. This occurrence indicates a much wider range of palygorskite-rich clay deposition than previously recognized. The lithology is 99% clay and 1% sand to silt size diagenetic quartz grains. The clay consists of approximately 85% palygorskite, 15% montmorillonite and trace amounts of titanium oxides. EDS analyses on palygorskite are largely consistent with sedimentary palygorskites from other coastal marine settings, however palygorskite has a low total Fe content (average = 0.40 wt% expressed as Fe2O3) compared to many other sedimentary palygorskites. Montmorillonite chemical compositions are typical and compared to the palygorskite have substantially higher Fe2O3 concentrations (average = 3.90 wt%). The low percentage of coarse grains in the lithology combined with a high proportion of palygorskite and lack of detrimental trace minerals suggest the deposit is of industrial grade; however, it has limited reserves (6,000 m3). The unit could be potentially used in a wide array of environmental applications which are needed in the region including liners for landfills and constructed wetlands. The unit is in a geographic location which would serve the expanding economy of the region. This resource has the potential to have great impact on the quality of the local environment and the economy of a region under great environmental threat. [ABSTRACT FROM AUTHOR]

The forests of the northeast Yucatan Peninsula supports wild ungulate populations such as the white-tailed deer (Odocoileus virginianus (Hays 1874), brocket deer (Mazama americana Erxleben 1777 and M. pandora Merriam 1901) and collared pecari (Pecari tajacu Merriam 1901). For its conservation and use, it is necessary to know the current status of wild ungulates populations. Basic ecological aspects such as density and distribution of the ungulate populations in different vegetation types were evaluated. The study area was El Edén Ecological Reserve (EER), located in the northern Yucatan Peninsula in Quintana Roo State, Mexico. The method used to assess ungulate density and distribution was the strip transect counts. The transects were set on the existing roads and footpaths. Using GIS, the habitat and five vegetation types were classified: secondary vegetation (acahual), tropical evergreen forest, tintales, savanna of palms and aquatic vegetation. Thirty eight observations of white-tailed deer were obtained, 14 of brocket deer and 6 groups of pecaries in 293.4 km of routes. The observation period was between September 2004 and April 2005 (six months of sampling). The absolute density of the white-tailed deer was 5,5 ± 4,1 ind/km², for the pecan was 1,9 ± 0,8 ind/km² or 0,2 ± 0,1 herd/km² and for brocket deer was 1,7 ± 1,8 ind/km². Acàhual was the vegetation type where white-tailed deer and collared pecan were found. This is the first time that AL americana was registered in this region of the State. These results suggest the important role that have the EER to conserve ungulates, nevertheless the continued risk of hurricanes and fires. The white-tailed deer population is high compared with other tropical zones. [ABSTRACT FROM AUTHOR]

Research on the dynamics of tropical forest land use and cover change (LUCC) has focused on the three scenarios: (1) deforestation/degradation; (2) settled, degraded areas in recovery, and (3) sparsely settled, expansive, intact forest. Through examination of a central Quintana Roo, Mexico case study we propose a fourth scenario of a ‘sustainable landscape’: an inhabited, productively used, forested landscape that nonetheless shows little change or net gains in forest cover over the last 25 years. We use Landsat images to demonstrate a low incidence of net deforestation, 0.01% for the 1984–2000 period, the lowest recorded deforestation rate for southeastern Mexico. Institutional innovations such as an agrarian reform process that established large common property forests for non-timber forest product extraction, and later innovations such as sustainable forest management institutions have driven the outcome of low net deforestation, added to multiple organizational processes that promote sustainable land use. [Copyright &y& Elsevier]