scholarly journals Land use impacts poison frog chemical defenses through changes in leaf litter ant communities

2019 ◽  
Author(s):  
Nora A. Moskowitz ◽  
Barbara Dorritie ◽  
Tammy Fay ◽  
Olivia C. Nieves ◽  
Charles Vidoudez ◽  
...  

AbstractMuch of the world’s biodiversity is held within tropical rainforests, which are increasingly fragmented by agricultural practices. In these threatened landscapes, there are many organisms that acquire chemical defenses from their diet and are therefore intimately connected with their local food webs. Poison frogs (Family Dendrobatidae) are one such example, as they acquire alkaloid-based chemical defenses from their diet of leaf litter ants and mites. It is currently unknown how habitat fragmentation impacts chemical defense across trophic levels, from arthropods to frogs. We examined the chemical defenses and diets of the Diablito poison frog (Oophaga sylvatica), and the diversity of their leaf litter ant communities in secondary forest and reclaimed cattle pasture. Notably, this research was performed in collaboration with two high school science classrooms. We found that the leaf litter of forest and pasture frog habitats differed significantly in ant community structure. We also found that forest and pasture frogs differed significantly in diet and alkaloid profiles, where forest frogs contained more of specific alkaloids and ate more ants in both number and volume. Finally, ant species composition of frog diets resembled the surrounding leaf litter, but diets were less variable. This suggests that frogs tend to consume particular ant species within each habitat. To better understand how ants contribute to the alkaloid chemical profiles of frogs, we chemically profiled several ant species and found some alkaloids to be common across many ant species while others are restricted to a few species. At least one alkaloid (223H) found in ants from disturbed sites was also found in skins from pasture. Our experiments are the first to link anthropogenic land use changes to dendrobatid poison frog chemical defenses through variation in leaf litter communities, which has implications for conservation management of these threatened amphibians.

2020 ◽  
Vol 6 (1) ◽  
pp. lxxv-lxxxvii ◽  
Author(s):  
Nora A. Moskowitz ◽  
Barbara Dorritie ◽  
Tammy Fay ◽  
Olivia C. Nieves ◽  
Charles Vidoudez ◽  
...  

2006 ◽  
Vol 53 (10) ◽  
pp. 37-45 ◽  
Author(s):  
A. Bahremand ◽  
F. De Smedt ◽  
J. Corluy ◽  
Y.B. Liu ◽  
J. Poórová ◽  
...  

The spatially distributed hydrologic model WetSpa combines elevation, soil and land use data within GIS, to predict flood hydrographs and spatial distribution of hydrologic characteristics in a watershed. The model is applied to the Margecany–Hornad river basin (1,131 km2) in Slovakia. Daily hydrometeorological data from 1991–2000, including precipitation data from nine stations, temperature data from four stations and evaporation data measured at one station are used as input to the model. Three base maps, i.e. DEM, land use and soil type are prepared in GIS form, using 100 × 100 m cell size. Results of the simulations show good agreement between calculated and measured hydrographs. The model predicts the daily/hourly hydrographs with 75–80% accuracy according to the Nash–Sutcliff criteria. For assessing the impact of land use changes on floods, the calibrated model is applied for a reforestation scenario, which considers a 50% increase of forest areas. The model results show that the reforestation scenario decreases the peak discharge by 12%. Investigation of peak discharges from the whole simulation period, shows that the scenario results are reduced by 18% on average, while for small discharges the reduction is even about 34%. The time to peak of the simulated hydrograph of the reforestation scenario is 20 hours longer than for the present land use.


2017 ◽  
Vol 68 (11) ◽  
pp. 1999 ◽  
Author(s):  
Pierce M. McNie ◽  
Russell G. Death

The impacts that land-use changes have on cave-stream fauna have not been considered widely in the investigations of land-use impacts on stream ecology. The present study examines how above-ground agriculture may influence cave-stream invertebrate communities. The invertebrate communities in four cave streams and their surface counterparts were sampled in 2014–2015, including two drained predominantly agricultural catchments and two drained forested catchments. These communities were examined alongside habitat and GIS land-use data to determine the relationship between above-ground land use and the stream communities. Invertebrate community composition and ecological health for surface streams was different between the agricultural and forest catchments. These differences were less pronounced within the cave-stream communities. Sedimentation was the principal agricultural stressor in the cave streams. The overall effects of agriculture were lower within the cave streams than on the surface; this is likely to be due to the reduced number of potentially deleterious stressors on cave streams.


2013 ◽  
Vol 10 (10) ◽  
pp. 6323-6337 ◽  
Author(s):  
S. J. Smith ◽  
A. Rothwell

Abstract. We examine historical and future land-use emissions using a simple mechanistic carbon-cycle model with regional and ecosystem specific parameterizations. We use the latest gridded data for historical and future land-use changes, which includes estimates for the impact of forest harvesting and secondary forest regrowth. Our central estimate of net terrestrial land-use change emissions, exclusive of climate–carbon feedbacks, is 250 GtC over the last 300 yr. This estimate is most sensitive to assumptions for preindustrial forest and soil carbon densities. We also find that land-use change emissions estimates are sensitive to the treatment of crop and pasture lands. These sensitivities also translate into differences in future terrestrial uptake in the RCP (representative concentration pathway) 4.5 land-use scenario. The estimate of future uptake obtained here is smaller than the native values from the GCAM (Global Change Assessment Model) integrated assessment model result due to lower net reforestation in the RCP4.5 gridded land-use data product.


2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Eduardo Francisco da Silva-Junior

Abstract Aim To conduct a review of the literature in order to identify the general stream metabolic responses to land use change. Methods I conducted a scientometric review analyzing the distribution of the studies among different environments, the land use scale used, and the general trends in stream metabolism response under each kind of land-use impact. Major Results Most of the analyzed studies were conducted in temperate environments, studying land-use impacts at catchment scale. Ecosystem metabolism responded to land use impacts most of the cases, especially under agricultural pressure. The general responses to land-use alterations were increases in rates of Gross Primary Production (GPP) and ecosystem Respiration (R). Primary production increases were mostly related to light and nutrient concentration increases, while R was usually related to water nutrient concentration, temperature and amount of particulate organic matter, but this general behavior can change under high impact levels where sometimes GPP decreases in response to turbidity increases. Riparian vegetation restoration have a positive effect in driving stream metabolic conditions in the direction of pristine condition, but the effectiveness of this approach is reduced in highly impacted systems. Conclusions To elucidate the mechanistic relations between stream metabolic changes and land use impacts is still one fundamental aspect to study in order to best predict effects of land use changes and establish management and protection programs. Thus, studies should focus on the causative relations between stream processes and land use changes considering different scales and multiple stress scenarios in order to improve our understanding about factors that drive the observed metabolic changes.


2019 ◽  
Vol 24 (2) ◽  
pp. 141-151
Author(s):  
Aji Nuralam Dwisutono ◽  
Sri Wilarso Budi ◽  
Istomo Istomo

The characteristics of tropical peatlands are still able to form a high diversity of plants. Conversion of tropical peatlands affects the composition of plants. The aim of this study was to find out effect of land use changes to the composition and diversity of plants in the Peat Hydrological Unit (PHU) Mendahara - Batanghari River. The research was conducted in three land use categories, namely secondary forest, coffee plantation, and oil palm plantation (subdivided into oil palm plantation 1 and oil palm plantation 2). In each study location, sample lane 20 m x 200 m were made. Overall, we found 77 species of plants. The results showed   number of plant species decreased due to changes of land use. There are 51 - 53 species of plants in secondary forest areas (out of a total of 58 species) that are not found in oil palm and coffee plantations areas. Differences in composition were also shown in the low value of community similarity (<50%). In the oil palm and coffee plantation areas, plant communities tend to be dominated by pioneer plants such as Melicope lunu-ankenda, Coffea liberica, Macaranga triloba, and Melastoma malabathricum. Secondary forest was dominated by plants species that characterize peatlands such as Tetramerista glabra, Parastemon urophyllus, Knema percoriacea, Litsea costalis var. nidularis and Madhuca motleyana. Changes in land use also reduce the level of diversity (H 'and R) at various levels of growth. Whereas in the oil palm and coffee plantation areas tend to form uniform stands (indicated through index E which describes the abundance distribution in community and index C which describes the dominance of species). Generally, the distribution pattern of plants is clumped. Uniform distribution was found in K. percoriacea and L. costalis var. nidularis. Keywords: land use changes, peatland characteristics, plant composition, plant diversity


Soil Systems ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 65
Author(s):  
William D. Eaton ◽  
Katie M. McGee ◽  
Elizabeth Hoke ◽  
Alex Lemenze ◽  
Mehrdad Hajibabaei

Inga edulis and Pentaclethra macroloba are dominant N-fixing forest trees in Costa Rica, likely important for recovery of soil N and C after deforestation, yet little is known of their soil microbiomes nor how land use impacts them. Soils from both trees in a primary and secondary forest were assessed for N-cycle metrics and DNA sequence-based composition of total bacterial, potential N-fixing bacterial, and potential ammonium oxidizing bacterial genera. The compositions of the functional groups of bacteria, but not their total relative abundance of DNA, were different across the soils. The P. macroloba soils had greater NO3− levels and richness of both functional groups, while I. edulis soils had greater NH4+ levels, consistent with its NH4+ preference for root nodule development. The bacterial communities were different by habitat, as secondary forest I. edulis microbiomes were less rich, more dominant, possibly more affected by the disturbance, or reached equilibrium status quicker than the richer, less dominant P. macroloba microbiomes, which may be developing slower along with secondary forest succession, or were less affected by the disturbance. Functional redundancy and switching of 10 N-cycle bacterial genera was evident between the primary and secondary forest soils, likely to maintain stable levels of N-cycle activity following disturbance. In summary, the two tree soil microbiomes are different, land use differentially affects them, and, thus, both tree species should be used during forest regeneration strategies in this region.


Author(s):  
Koen Deforce ◽  
Jan Bastiaens ◽  
Philippe Crombé ◽  
Ewoud Deschepper ◽  
Kristof Haneca ◽  
...  

Abstract The results from analyses of botanical remains (pollen, wood, charcoal, seeds) from several archaeological features excavated in Kluizen (northern Belgium) are presented. The region was largely uninhabited until the Iron Age and Roman period when a rural settlement was established, resulting in small-scale woodland clearance. The site was subsequently abandoned from c. AD 270 till the High Middle Ages. The results of the archaeological and archaeobotanical analyses provide information on changes in land use and resulting dynamics of woodland cover and composition between c.600 BC and AD 1200, with a spatial and temporal resolution unrivalled in northern Belgium. Especially the long period of woodland regeneration following abandonment of the site around AD 270, covering the Late Roman and Early Medieval period, could be reconstructed in detail. Abandoned fields were first covered with pioneer woodland (Salix, Corylus and Betula), then Quercus-dominated secondary forest and finally a late-successional forest with Fagus sylvatica, Carpinus betulus and Ilex aquifolium, an evolution that took over 300 years. The results also indicate that the observed increase of Fagus during the Early Middle Ages, which was never an important element in the woodland vegetation in northern Belgium before, was related to climatic changes rather than anthropogenic factors.


2018 ◽  
Vol 22 (8) ◽  
pp. 4311-4328 ◽  
Author(s):  
Lan Wang-Erlandsson ◽  
Ingo Fetzer ◽  
Patrick W. Keys ◽  
Ruud J. van der Ent ◽  
Hubert H. G. Savenije ◽  
...  

Abstract. The effects of land-use change on river flows have usually been explained by changes within a river basin. However, land–atmosphere feedback such as moisture recycling can link local land-use change to modifications of remote precipitation, with further knock-on effects on distant river flows. Here, we look at river flow changes caused by both land-use change and water use within the basin, as well as modifications of imported and exported atmospheric moisture. We show that in some of the world’s largest basins, precipitation was influenced more strongly by land-use change occurring outside than inside the basin. Moreover, river flows in several non-transboundary basins were considerably regulated by land-use changes in foreign countries. We conclude that regional patterns of land-use change and moisture recycling are important to consider in explaining runoff change, integrating land and water management, and informing water governance.


Sign in / Sign up

Export Citation Format

Share Document