Scrub Sites Research Articles

Comparative ecology of two closely associated scrub-dominating oaks in South Florida: Quercus myrtifolia and Q. geminata (Fagaceae)

Recent authors have developed a detailed perspective on the parallel sympatric radiation into similar habitats throughout North America of oak species (Quercus, Fagaceae) representing different sections, including prominently Florida. Quercus myrtifolia and Q. geminata are a localized example of that radiation: two species in different sections codominating scrub habitats in the coastal Southeast Florida study area. Within that context the two are usually encountered at shrubby sizes almost without spatially related habitat differentiation, raising the question of how they coexist in essentially the same niche. The present project addresses this pronounced niche overlap with two different approaches: first, field exploration to discern local exceptions to the apparent near-inseparability of the two oaks, and second, to identify environmentally related differential growth responses. Exploring several scrub sites in Palm Beach and Martin counties, Florida, the study found three deviations from the usual intimate shrubby-site association having Q. myrtifolia proportionally dominant. Those deviations are: 1. Shrubby-sized Q. geminata tends proportionally to dominate dune bases vs. Q. myrtifolia dominating higher dune slopes. 2. Tree-sized Q. myrtifolia proportionally dominates sheltered scrub dune localities. 3. Tree-sized Q. geminata proportionally dominates exposed scrub dunes. During site maturation the two species diverge in relative abundance depending on sheltered shade vs. open exposure until fire or hurricanes restart succession from their intermixed subterranean portions. When young and shrubby, in exposed conditions as opposed to in partial shade, Q. geminata tends toward reduced leaf blade areas and increased marginal curling parallel to the long axis. By contrast, Q. myrtifolia in exposed conditions tends toward broad diversity in three-dimensional foliar conformations. Different foliar morphotypes characterize different Q. myrtifolia clumps.

Lateglacial and Holocene palaeoenvironments at Sierra La Madera, northwestern Mexico: Sharp signals of Younger Dryas and North American monsoon

AbstractDuring the last glacial termination, the climate system experienced intense global variations whose causes and impacts are not fully defined, particularly for low latitudes. The northwestern Mexico Sky Islands present a climate‐sensitive ideal setting to record palaeoecological and palaeoclimatic changes due to their physiographic complexity and location in the ecotone between temperate and tropical ecosystems. High‐resolution pollen analysis and a detailed sedimentological study were conducted at the Ciénega Tonibabi tropical thorn scrub site. The 15 540–0 cal a bp nearly continuous record shows that the North Atlantic Ocean did have a cold and humid climatic influence during the glacial stages of the end of the Pleistocene, including a sharp pulse during the Younger Dryas. However, a shift to the Pacific Ocean influence occurred during the Holocene, which led to the development of the El Niño conditions prevailing today. Colder and warmer phases follow one another with higher or lower winter precipitation, including a sharp Bølling–Allerød and development and intensification of the North American monsoon. They are reflected in hydrological changes as well as in the advances, retreats and intermingling of coniferous forests and tropical thorn scrub.

Structure and floristic diversity of woody plants of the Tamaulipas Thornscrub in an ecological reserve in northeast Mexico

The Tamaulipas thorn scrub in northeastern Mexico is one of the ecosystems most degraded by human action. One of the measuresimplemented for its protection is the declaration of the creation of ecological reserves, which are areas destined for the conservationof ecosystems and what is found in them. This study seeks to know if the sites of the ecological reserve that have been reforestedwill present a lower abundance of individuals, cover, basal area and volume of wood than the rest of the reserve. Stratified randomsampling was carried out to determine the structure and diversity of the vegetation. 10 strata (sites) were established, where siteswith rectangular plots of 10 m × 20 m were established. Woody individuals with a basal diameter> 3 cm were evaluated in eachplot and the total height, basal diameter and crown diameter were measured. In the data analysis for each site, the basal area,canopy cover, timber volume and diversity were calculated, with these values an analysis of variance (ANOVA), WinTWINScluster analysis was performed and the vertical distribution index of species was determined. (A). Variables such as basal area,coverage, volume, diversity were determined, in addition to a WinTWINS cluster analysis, analysis of variance (ANOVA) as wellas the vertical distribution index of species (A). The mesquite-huizache site presented the highest basal area values; the ash scrub 2presented the highest coverage, while the vegetation in a site reforested six years ago, presented greater basal area and timbervolume than mature scrub and ash scrub sites. Four groups are distinguished in the TWINSPAN classification. The verticaldistribution registers two strata where a high proportion of species is found. The hypothesis is accepted, since the sites presentdifferences in their structure and diversity, being the reforested sites with 2 and 4 years those that presented the lowest abundanceof individuals, cover, basal area and timber volume.

Differences in characteristics of egg sacs of Metepeira calamuchita (Araneae: Araneidae) in two environments of the Monte Desert, Mendoza, Argentina

We examined egg sac characteristics and oviposition sites of Metepeira calamuchita (Piel, 2001) (Araneidae) at two different habitat types, creosote bush scrub and Prosopis spp. forest patches, at the Ñacuñan Biosphere Reserve located in the Monte Desert of Mendoza, Argentina. At each site, we manually collected egg sacs of M. calamuchita between November and April. We recorded egg sac location, presence of detritus on the egg sac and its colouration. At scrub sites, there was a greater number of egg sacs anchored to the vegetation, while in forest sites most egg sacs were suspended by web threads. In addition, more egg sacs covered with detritus were found at scrub sites, but we did not find an association between egg sac colouration (brown/dark brown) and habitat type. Location of the egg sac and presence of detritus could function as defence strategies in environments with different pressures of egg sac predators and parasitoids.

Mapping spatially explicit vegetation gaps in Florida rosemary scrub using unmanned aerial vehicles

AbstractAdvances in remote sensing technologies offer new means to monitor habitats of importance on large scales. Florida rosemary scrub is one such threatened habitat, found in patches across the landscape in relatively elevated areas, and is often characterized by shrub‐less areas (gaps) among the dominant shrubs, which provide favorable microhabitats for many endemic and endangered plants and animals. However, gaps are difficult and time‐consuming to characterize, especially across large areas, using traditional ground‐based field methods. We developed and tested a method for rapidly classifying gaps using an unmanned aerial vehicle (UAV or drone). Aerial data were collected by a UAV‐mounted camera in April 2018, and stratified, random ground surveys to verify UAV data were conducted March through April 2018 at Archbold Biological Station in south‐central Florida, USA. We used mosaicked and georeferenced digital surface and terrain models to calculate vegetation height across 33 rosemary scrub sites (~230,000 m2 at 0.064 m2 pixel resolution). Gaps were defined as >1 m2 areas where vegetation height was <10 cm. We found that gap areas from UAV models and field surveys were significantly correlated across varying gap sizes, times‐since‐fire, and relative elevations. We also observed a significant decrease in mean gap area and percent gap space with increasing time‐since‐fire, a pattern consistent with smaller‐scale, ground‐based sampling, and a marginally significant increase in gap area with relative elevation. This remote sensing method lends itself to better exploration of how gap areas, their spatiotemporal patterns, and associated fire history, elevation, soil, and other geographic data affect structural vegetation dynamics across the landscape. This study illustrates the success of UAV modeling of gap space in Florida rosemary scrub, a result of regional consequence for the southeastern United States, but more broadly, it encourages the use of UAV technology as a tool to enhance traditional field‐based methods in systems globally. As habitat fragmentation and loss become increasingly problematic for the conservation of threatened habitats, understanding these complex spatial dynamics is crucial to the conservation and management of vegetation communities and their biodiversity.

Diel activity patterns of alpine carabid beetles (Coleoptera: Carabidae) differ according to habitat type

In lowland areas, carabid beetles show diurnal or nocturnal activity patterns depending on habitat type. However, the diel activity patterns of carabid beetles in alpine areas are poorly understood. We conducted field studies in the alpine area of Mt. Hakusan in central Japan to determine the diel activity patterns of carabid beetles according to habitat type and ground surface temperature. Using baited pitfall traps, we collected samples every three hours over a 24-hour period in the summers of 2015 and 2016 in Pinus scrub, snowbed, and fellfield sites. In both years, the numerically dominant species were Pterostichus janoi Jedlicka, 1952 in the Pinus scrub, Bembidion sp. in the snowbed, and Bembidion sp. and Colpodes xestus (Bates, 1883) in the fellfield. Carabid beetles on alpine Hakusan showed activity patterns that varied depending on habitat type or ground surface temperature. Bembidion sp. showed diurnal activity patterns in the snowbed but nocturnal activity patterns in the fellfield when the diurnal temperature range was large. However, this species was active throughout the day and night in these habitats when the diurnal temperature range was small. By contrast, P. janoi in the Pinus scrub and C. xestus in the fellfield were mainly active nocturnally in both years, regardless of temperature fluctuations. Because alpine areas are generally characterized by harsh and changeable climates, some alpine carabids such as Bembidion sp. are probably adapted to show versatile activity patterns in response to changeable microclimatic conditions.

Grazing pressure and the interaction dynamics of the endemic Cyprus Warbler Sylvia melanothorax and its recently colonising congener the Sardinian Warbler S. melanocephala

SummaryThe recent classification of the endemic Cyprus Warbler to a Species of European Conservation Concern by BirdLife International has renewed interest in its interaction with the Sardinian Warbler, a widespread Sylvia that was first confirmed as breeding in Cyprus in the 1990s and has since expanded in numbers and range. In areas where the Sardinian Warbler has become established, there has been a reduction in the abundance of the Cyprus Warbler, leading some researchers to suggest the recently arrived species is outcompeting its endemic congener. However, clear evidence of competition between the two species has not been found, and more recent research has suggested the closely related warbler species show preferences for subtly different scrub habitats, which might be influenced by the extent of grazing. We carried out line transect surveys during the breeding season at 48 scrub and open woodland sites across Cyprus in 2012, 2014 and 2016, recording Cyprus Warblers and Sardinian Warblers in order to estimate their densities. In addition, we recorded vegetation characteristics and estimated grazing pressure at these 48 sites. Our analysis showed that the Sardinian Warbler continues to increase in abundance over time and its higher abundances were associated with lower Cyprus Warbler abundances. Sardinian Warbler however was negatively associated with all but very low grazing pressure, whereas the Cyprus Warbler was more tolerant of grazing. Our findings suggest continued grazing of scrub sites is important for the maintenance of suitable habitat for the endemic warbler, which will help improve its conservation status.

Richness and activity of arthropodophagous bats in an arid landscape of central México

The insectivorous bats of arid and semi-arid ecosystems have been poorly studied in Mexico. The aim of this work was to determine the richness and activity of insectivorous bats in arid landscapes of central Mexico over an annual cycle and identify the landscape and environmental features related to relative abundance patterns of bats. We carried out captures with mist nets and active acoustic monitoring in 10 transects, semi-active monitoring in eight stations, and passive monitoring in two desert grassland and scrub sites in Aguascalientes and Jalisco, from January to December 2012. The activity index of each insectivorous species was calculated and related to the local features at the landscape level. An automated monitoring weather station was established in the study area to explore the potential effect of environmental conditions on activity through time. Two species of insectivorous bats were captured: Myotis melanorhinus and Myotis occultus; seven additional species belonging to three families were acoustically identified, with Tadarida brasiliensis as the most active species. Activity levels were concentrated during the spring (April-June) and from mid-summer to late fall (August-October). The null activity in winter (January-March) and the increased activity of T. brasiliensis in the spring suggest migratory movements of the species in the region. The highest values of the activity index were recorded in the proximity of water bodies and ravines. Overall activity was recorded at temperatures between 6.8 and 20.3 °C, and under wind speeds between 1.6 and 24.1 km/h.

High resilience to extreme climatic changes in the CAM epiphyte Tillandsia utriculata L. (Bromeliaceae)

Climate change is expected to increase the frequency of extreme climatic events, yet few studies have addressed the capacity of plant species to deal with such events. Species that are widespread are predicted to be highly plastic and able to acclimate to highly changing conditions. To study the plasticity in physiological responses of the widely distributed epiphyte Tillandsia utriculata, we transplanted individuals from a coastal scrub and broadleaf evergreen forest to a similar coastal scrub site and forest. After a 45-day acclimation, the plants were moved to a semi-controlled greenhouse at each site, and then subjected to a 20-day drought. Physiological variables were measured during the acclimation and the drought. The individuals of scrub and forest populations had similar relative water content and carbon assimilation in the contrasting conditions of the two transplantation sites despite the high discrepancy between the environments at their original site. Electron transport rates were higher in individuals from the scrub population. Electron transport rates were also higher than estimated from carbon assimilation, suggesting that photorespiration was present. The individuals of the coastal scrub population had a higher capacity to dissipate excess energy this way. The relative distance index of plasticity was high overall, indicating that some traits are highly plastic (titratable acidity, carbon assimilation) in order to maintain the stability of others (maximum quantum yield Fv /Fm and relative water content). We conclude that T. utriculata is a highly plastic species with a high capacity to tolerate extreme environmental changes over a short time.

Propionibacterium Acnes Persists Despite Various Skin Preparation Techniques

To investigate the efficacy of various skin preparations at eradicating Propionibacterium acnes in the dermal layer of the skin. Twelve healthy volunteers consented to participate in this study. Each subject's upper back was prepped using 4 different techniques: an isopropyl alcohol control, chlorhexidine gluconate paint, chlorhexidine gluconate plus a mechanical scrub, and a high-concentration chlorhexidine gluconate plus a mechanical scrub. A 3-mm dermal punch biopsy specimen was obtained at each preparation site. The 4 punch biopsy specimens were cultured for 14days to assess for P.acnes growth. A Fisher's exact test was used to compare the proportion of positive cultures in each group and across biopsy sites. A Skillings-Mack test was used to compare the degree of culture positivity between the treatment arms. There were no reported complications in any of our subjects. P.acnes grew in 7 of the 12 control sites, 5 of the 12 chlorhexidine gluconate sites, 6 of the 12 chlorhexidine plus mechanical scrub sites, and 6 of the 12 high-concentration chlorhexidine gluconate plus mechanical scrub sites. There were no statistically significant differences between any of the treatment arms (P= .820). P.acnes persisted despite a variety of clinically relevant skin antisepsis preparations and techniques. Level II, prospective comparative study.

Estimates of Habitat Use by Rabbits (Sylvilagus spp.) from Fecal Pellet Counts Varies by Plot Design in Southern California

Studies of rabbits and hares often use fecal pellet counts to estimate population density, create indices of abundance, and monitor habitat use, because fecal pellet counts are more easily deployed and less labor intensive than visual surveys and live trapping. In some habitats, plot size and shape can affect the measured pellet density and the resulting estimates of habitat use by rabbits. We compared rabbit (Sylvilagus spp.) fecal pellet density estimates derived from 0.155-m2 rectangular, 0.155-m2 circular, 1-m2 square, and 1-m2 circular plots in southern California chaparral and coastal sage scrub communities to evaluate habitat use by rabbits. Pellet plots were not an effective sampling design in our chaparral site where rabbit pellet density was low. Our coastal sage scrub site had an abundance of fecal pellets, and pellet density estimates varied by plot design. The 0.155-m2 plots were more easily deployed and counted, however they produced higher estimates of fecal pellet density, exhibited greater variance, and were unable to detect habitat differences in fecal pellet density. The 1-m2 plots required more effort but produced lower pellet density estimates, exhibited less variation, and were both able to detect habitat differences in fecal pellet density. We recommend that researchers conducting rabbit fecal pellet counts in Californian Mediterranean scrub habitats use 1-m2 circular plots for their ease of deployment, counting, and clearing and for their greater detection and precision in estimates of pellet densities.

Climate, topography, and dust influences on the mineral and geochemical evolution of granitic soils in southern Arizona

Mineral weathering transforms rock into soils that supply nutrients to ecosystems, store terrestrial carbon, and provide habitat for organisms. As a result, the mineralogy and geochemistry of soils from contrasting environments are well-studied. The primary objective of this research was to examine how climate, topography, and dust interactively control the mineral and geochemical composition of granitic soils that span an environmental gradient in southern Arizona. Two field sites were selected within the Catalina Critical Zone Observatory that exhibit significant range in precipitation (25 to 85cmyr−1), temperature (24 to 10°C), and vegetation composition (desert scrub→mixed conifer). Within each site, two catena end member pairs were selected to represent variation in local topography which included divergent, water-shedding summits and convergent, water-gathering footslopes. Soils and parent rock were studied using x-ray diffraction and x-ray fluorescence. Dust samples were collected from ridgetop dust traps at the desert scrub site and examined using x-ray fluorescence. The desert scrub soils showed enrichment in biotite, total feldspar, and Fe+Mg whereas the mixed conifer soils were depleted in feldspars and enriched in Fe+Mg. Depletions of Na, Si, and K+Ca occurred in both the desert and mixed conifer ecosystems, with the convergent soils in the conifer sites exhibiting the greatest degree of elemental loss. We examined dust in the regolith after identifying mineral and elemental enrichments in both ecosystems. Dust fraction estimates ranged from 2 to 21% in desert soils and 9 to 19% for the mixed conifer soils. Our results confirm the interactive role of bioclimate, topography, and dust in driving the geochemical evolution of soils and cycling of nutrients in desert and conifer ecosystems.

Landowner participation in forest conservation programs: A revealed approach using register, spatial and contract data

Incentive based voluntary conservation programs have gained prominence as a regulation mechanism to protect ecosystem services on private land either through the set-aside of land for reserves or by altering land management practices. A crucial challenge for voluntary approaches is however to ensure private landowner involvement and get the ecosystem services delivered where they are most demanded by society. To promote participation and ensure an instrumental design of voluntary initiatives that is coherent with this, there is a need to understand the motivations of the landowners and determinants of their participation choice. We investigate landowners’ willingness to participate in protecting oak scrub sites in Denmark. Combining contract data of the landowners’ actual choices, GIS information on area specific characteristics and detailed individual level register data, we develop and implement a framework for analysing revealed choice of private landowners’ in voluntary conservation programs. We find that both the physical characteristics of the property and the sociodemographic characteristics of landowner in question matter, along with the information flow provided from the regulator. Results provide impetus into the design of future conservation policies, in terms of how, to whom and where to target efforts.

Drought and extreme temperature tolerance for Tillandsia dasyliriifolia , an epiphytic bromeliad from the northern coastal dune scrubland in Yucatan, Mexico

The ecophysiological investigations about epiphytic plants have focused on the establishment of mechanistic explanations of how plants respond to changes in their environment. The main objective of this work was to assess the drought and extreme temperature tolerance of Tillandsia dasyliriifolia individuals growing in two coastal dune scrub sites with different precipitation patterns and microhabitat distribution. This study was focused on the effect of plant size on tolerance parameters. Drought and extreme temperature tolerance were evaluated in small (S1, 9 cm) and large individuals (S2, 35 cm). Tolerance between sites was not different but varied between size classes. Tillandsia dasyliriifolia shows moderate tolerance to drought in comparison to more succulent plants. The 50% of the leaves in small plants died after 40 days of drought and after 60 days for large plants. T. dasyliriifolia also exhibits moderate tolerance to extreme temperatures tolerance, small plants tolerate a temperature range from 11 ºC to 40 ºC and the range for large plants is a little broader (9 °C to 43 °C).

Zooplankton generation following inundation of floodplain soils: effects of vegetation type and riverine connectivity

We investigated the potential for zooplankton to emerge following inundation of dry soils on the lower Waikato River floodplain, North Island, New Zealand. Soil cores were collected from native forest remnants, scrub (predominantly Salix spp.) and pasture, and from sites inside or outside of stopbanks, to examine the effects of vegetation type and hydrological disconnection. We hypothesised that more larger-bodied zooplankton would emerge from forested floodplain areas, and that areas with high connectivity with the river would produce more zooplankton. Zooplankton appeared from soil cores within 3 days of wetting and no new taxa arose after 12 days. Community composition differed between vegetation types, with larger bodied cladocerans and copepods dominating forested and scrub sites, and rotifers dominating pastoral sites. Connectivity did not play a statistically significant role in determining community composition. Soil conditions were implicated as important in affecting emergent zooplankton community composition, with copepods and cladocerans characteristic of sites with wetter soils and bdelloid rotifers abundant in open sites with higher soil temperatures. Our findings indicate scrub and forested floodplains can be important areas for large-bodied zooplankton production, and that maintaining vegetative heterogeneity on floodplains may promote trophic subsidies for migrating juvenile fish as floodwaters subside.

Heterogeneity of bird communities in a mosaic of habitats on a restinga ecosystem in southeast Brazil

Restinga occurs as a narrow band of coastal habitats throughout the Atlantic Forest, although it presents considerable variation in vegetation structure, which likely contributes to heterogeneity in species inhabiting this endangered ecosystem. The goal of this study is to examine how variation in vegetation and abiotic conditions in the restinga ecosystem may contribute to heterogeneity of bird communities in Restinga de Jurubatiba, Brazil. Temperature, relative humidity, and vegetation structure were sampled to characterize four sites (dry forest, flooded forest, open scrub and closed scrub). Birds were sampled using observations, mist-netting and voice recordings. Results indicate that major differences of all variables occur between forest and scrub in both vegetation and birds. In addition, differences also exist within forests and within scrub, resulting in considerable heterogeneity among sampled areas. Scrub sites were richer in bird species (n = 58) than forest sites (n = 41), while closed scrub had the most species (n = 49). Also, 64% (47 of 73) of bird species were exclusive to forest or scrub habitats. Scrub habitats were more similar to each other than forest habitats. Normalized Difference Vegetation Index (NDVI) calculated from satellite images distinguished scrub sites and may be useful to monitor changes in vegetation patches through time. The restinga ecosystem is quite heterogeneous with considerable turnover in bird species composition and differences in vegetation structure. Forest strips may serve as connectors on the landscape and to help maintain species diversity and conservation of forest species. Also, this highly dynamic ecosystem, which includes a mosaic of habitat types, likely promotes resilience of bird populations under changing conditions.

Linking soil element-mass-transfer to microscale mineral weathering across a semiarid environmental gradient

Understanding controls on silicate weathering is critical to characterizing critical zone evolution. The objective of this study was to investigate how climate, vegetation, and landscape position control feldspar transformations across a semiarid environmental gradient. Granitic surface soil and saprock samples were collected from desert scrub and mixed conifer sites within the Santa Catalina Mountain Critical Zone Observatory where mean annual temperature ranges from 24°C to 10°C and mean annual precipitation from 25 to 85cm. Quantitative X-ray diffraction, X-ray fluorescence, and electron microprobe analyses were employed to quantify elemental changes in bulk soils and across plagioclase grains. The chemical depletion of Na in bulk soils ranged from 5.4 – 15% in the desert scrub sites relative to 16–33% in the mixed conifer sites. Plagioclase grain alteration was classified into unaltered, edge, and altered sections to compare microscale weathering and elemental variation. The Na/Al and Si/Al ratios decreased from unaltered, to edge, to altered grain sections in the mixed conifer sites, whereas the element ratios of the desert scrub system were similar between unaltered and edge grain sections, and only exhibited significant decreases in Na/Al and Si/Al ratios between edge and altered materials. The microscale depletion of Na and Si suggested increased silicate weathering in the cooler, wetter, and more biologically productive mixed conifer system compared to the hot, dry desert scrub system. The results also demonstrated a topographic control on mineral transformation where increased plagioclase weathering occurred in convergent footslope landscapes with little change in elemental depletion of soils in divergent summit sites.

A Cross-scale Study of Feldspar Transformation in the Santa Catalina Mountain Critical Zone Observatory

The critical zone evolves from coupled biological, physical, and geochemical processes that we quantify here across varying climatic and topographic conditions. The specific objective of this work was to examine how climate, landscape position, and vegetation drive feldspar weathering across the Santa Catalina Mountain Critical Zone Observatory, which exhibits considerable range in temperature (24 to 10°C), precipitation (25 to 85cm), and vegetation community composition (desert scrub → mixed conifer). Granitic soils and parent rock were characterized using a profile development index, quantitative x-ray diffraction, and electron microprobe analyses. Profile development indices increased linearly with increasing MAP/PET ratios (r2 = 0.48), with higher degrees of soil development in convergent footslope positions. Bulk soils from the desert scrub sites were enriched in total feldspar relative to quartz in both landscape positions, ranging from +2 to +24% compared to the mixed conifer soils, which exhibited maximum total feldspar depletions of -13% in the convergent soils and -3% in the divergent sites. Microscale Na depletions increased significantly from unaltered to altered feldspar grain sections, with more tightly constrained Na losses in the mixed conifer grains compared to those from the desert scrub environment. Greater soil development and feldspar transformation in the conifer soils documented interactive climate and vegetation controls on mineral weathering in bulk soils and at the microscale. Furthermore, the larger profile development indices in the convergent landscapes demonstrated the importance of studying hillslope-scale soil development along environmental gradients, where localized increases in mineral transformation likely results from greater moisture availability and organic inputs in water-gathering landscape positions.

Diversidad de escarabajos necrófilos (Coleoptera: Scarabaeidae, Silphidae, Staphylinidae y Trogidae) en una región semiárida del valle de Zapotitlán de las Salinas, Puebla, México

Mexico is constituted of arid and semiarid areas in more than half of its land extension, where most of their resources are available only during the rainy season. For those species that recycle resources, such as the carrion fauna, this represents a highly active season; however, the biological and diversity patterns of carrion fauna are poorly understood in these areas. Here, we studied the abundance, diversity and richness of the Scarabaeidae, Silphidae, Staphylinidae and Trogidae families in the Zapotitlán de las Salinas Valley in Puebla, Mexico. Over a one-year period, monthly samples were collected from five different vegetation systems that included the scrublands, a columnar cactus landscape, and altered vegetation. Samples were collected with the use of NTP-80 traps baited with squid, and data on abundance and richness were obtained and evaluated, with respect to monthly precipitation and sampling site location. We collected a total of 613 insects from 12 genera and 15 species. Across systems, Staphylinidae showed the greatest richness (nine species) and abundance (74.2%), followed by Scarabaeidae (21.9%), Silphidae (2.9%) and Trogidae (1%). Significant differences were observed between sites and months; nevertheless, no relationship was observed between abundance and temperature or precipitation. Across taxonomic groups, abundance and richness were most evident for scrub sites, while a greater abundance during the dry season was obtained. The results of this study indicated that the carrion faunal community composition is closely related to the type of vegetation and did not depend on the rainy season. In spite that lesser carrion fauna was observed in this area when compared to other regions of Mexico, this report constitutes a significant contribution to our understanding of the ecological role of this fauna in arid areas.

Bird ringing and nest recording in Britain and Ireland in 2011

This is the 75th annual report of the British Trust for Ornithology's Ringing Scheme, covering data received and work carried out in 2011. A review of priorities for the Scheme identified the need to increase submission of nest records through the Nest Record Scheme and to extend the network of Retrapping Adults for Survival (RAS) studies. Collection of different demographic parameters from the same site (eg nest records, numbers of breeding pairs, adult survival, etc) can provide a powerful tool to identify reasons for population change. Constant Effort Sites (CES) data showed long-term declines in abundance for four migrants (Willow Warbler Phylloscopus trochilus, Lesser Whitethroat Sylvia curruca, Sedge Warbler Acrocephalus schoenobaenus and Reed Warbler Acrocephalus scirpaceus) and three resident species (Willow Tit Poecile montana, Song Thrush Turdus philomelos and Reed Bunting Emberiza schoeniclus). Robin Erithacus rubecula and Reed Bunting had the lowest survival rates since CES began and survival-rate estimates were also significantly below average for Long-tailed Tit Aegithalos caudatus and Wren Troglodytes troglodytes, two small resident species that are particularly vulnerable to cold weather. Abundance of Blue Tit Cyanistes caeruleus, Great Tit Parus major, Goldfinch Carduelis carduelis and Bullfinch Pyrrhula pyrrhula recorded by CES increased. Nine of the 16 resident species covered by CES also had higher-than-average productivity, in particular the highest ever recorded for Dunnock Prunella modularis, Chaffinch Fringilla coelebs and Bullfinch. The number of Constant Effort Sites increased in 2011, with a higher percentage of reedbed habitat covered by the scheme, but fewer dry and wet scrub sites. In 2011 the number of RAS projects increased by 34 to 158. Survival trends were generated for 46 species and the use of colour marks has been promoted to increase the resighting probability of trap-shy species such as House Sparrow Passer domesticus and Starling Sturnus vulgaris, and for species with low recapture probability such as seabirds. As in 2010, the total number of birds ringed in 2011 (1,151,665) was the highest ever. It included 540,696 first-year birds, 383,136 adults (birds in their second calendar year or later) and 27,495 unaged birds. All ringing data for 2011 were computerised. In addition, there were 166,061 recaptures of ringed birds at or near the ringing site. The increased numbers of fully grown birds ringed is probably due to three main factors: high survival of some species, as suggested by CES results, combined with high productivity in 2011 and the increasing number of ringers in the Scheme catching higher numbers of birds. In total 20,702 BTO-ringed birds were recovered (found dead or recaptured away from the ringing site) in 2011, the highest ever as a result of the increased number of birds ringed in the past decade, combined with efforts to increase reports of ringed birds by the public, an increasing number of colour-ringing projects and associated resightings, and a change in the way recoveries are processed. Recoveries of 17 BTO- and 13 foreign-ringed birds that have extended our existing knowledge of movements of a species, are unusual movements, or are a new longevity record are also presented. In 2011 40,845 nest records were submitted (over 70% electronically), the highest total since 1998. Of these, 82% originated from England, 9% from Wales and 8% from Scotland, with the remaining 1% divided equally between Northern Ireland and the Republic of Ireland. Long-term nest productivity trends (1966–2010) were significant for 36 of the 71 species for which sufficient data were available, and seven of these (Nightjar Caprimulgus europaeus, Tree Pipit Anthus trivialis, Willow Warbler, Bullfinch, Coal Tit Periparus ater, Treecreeper Certhia familiaris and Chaffinch) showed a significant decline over time. The 2011 breeding season was characterised by an early start compared to the previous five years, possibly due to the warmest April on record.