Functional Diversity Plays a Role in Driving Beta-Diversity-Or Does It?

<div>Patrick and Brown (2018) suggest that functional diversity of the species pool has an important role in generating beta-diversity. Using a combination of path analysis and model selection, they ostensibly provide support for this hypothesis; however, they neglect to put theory and modeling into statistical and ecological context. Importantly, they present results that are not reproducible. Here, I present a re-analysis of their data with alternative hypotheses. I conclude that the drivers of beta-diversity are variable, with functional diversity typically having a reduced, if any, role compared to consistently stronger roles played by gamma-diversity or environmental variation on structuring beta-diversity.<br></div><div><br></div><div><br></div>Here I provided the data associated with the re-analysis. I also provide my R code and workspace for instant evaluation of my re-analysis and to allow for readers to reproduce the results.<div><br></div><div>Citation for the data:</div><div><div>Patrick, C. J., and B. L. Brown. 2018. Data from: Species pool functional diversity plays a hidden role in generating beta-diversity. American Naturalist, Dryad Digital Repository, http://dx.doi.org/10.5061/dryad.5n0c3.</div></div><div><br></div><div>Citation for Patrick and Brown (2018):</div><div><div>Patrick, C. J., and B. L. Brown. 2018. Species pool functional diversity plays a hidden role in generating beta-diversity. The American Naturalist 191: E159-E170.</div></div><div><br></div

Phylloicus hansoni larval population size structures in both predator-only and predator-third party stream settings

This data was collected in 2013 and 2011 in the southern slope of Trinidad’s Northern Range Mountains, within the Caroni River drainage. The dataset consists of larval caddisfly size distribution data across streams with different fish assemblages, with data on size, frequency and gut content data of predatory fish species.<div><br></div><div>The related study investigates the relationship between the size structures of the larval caddisfly (<i>Phylloicus hansoni</i> Denning) and different fish assemblages in Trinidadian streams in two settings:</div><div><div><b>KO:</b> Killifish-Only: upstream reaches where the predatory killifish, <i>Anablepsoides hartii</i>, is the only fish species</div><div><b>KG:</b> Killifish-Guppy: downstream reaches where killifish and the omnivorous guppy <i>Poecilia reticulata</i> coexist</div></div><div><br><div>The data files are four <b>.csv</b> text files, accessible via MS Excel, open office and openly accessible text edit applications.</div><div><br></div><div>___</div><div><br></div><div>The following data files are from 5 streams, each with reaches with differing fish assemblages in 2013.<br><div><br></div><div><b>PHYL-size_frequency_data.csv</b> - size frequency data consisting of body lengths and head capsule widths of caddisfly larvae:</div><div><b>- stream: </b>El Cedro = CED, Endler = END, Guard Dog Creek = GDC, Ramdeen = RDN, Trip Trace = TRT.</div><div><b>- reach:</b> stream setting - KG or KO</div><div><b>- instar.group: </b>HCW classification as Small = S (0.2 - 0.4 mm), Medium = M (0.5 - 0.8 mm), Large = L (0.9 - 1.1 mm)</div><div><b>- HCW:</b> head capsule width in mm</div><div><b>- count: </b>frequency</div><div><br></div><div><b>PHYL-site_survey_data.csv - </b>site survey data</div><div><b>(stream & reach </b>see above)<br></div><div><b>- transect</b> - transect id in the format <b>TTTRRX</b> (TTT = transect, RR = reach, X= sequential numerical id)</div><div><b>- wetted.width </b>in cm<br></div><div><b>- depth </b>in cm<br></div><div><b>- canopy.cover</b> in %<br></div><div><b>- CBOM:</b> coarse benthic organic matter gm^-2</div><div><b>- CPUE: </b>catch per unit effort<br></div><div><br></div><div><b>PHYL-fish_size_class_data.csv </b>- killifish size class data, with mean CPUE for each size class at each stream/reach:</div><div><b>(stream & reach </b>see above)<b><br></b></div><div><b>- fish.SC - </b>fish size classification: Juvenile = J (< 15 mm), Small = S (15-30 mm), Medium = M (30-45 mm), Large = L (45-60 mm), and Extra-Large = XL (> 60 mm)</div><div><b>- mean.CPUE</b>: mean CPUE (see above for definition) for specific stream and reach</div><div>___</div><div><br></div><div>The following data was collected from killifish in 2011. Appropriate institutional permits were obtained.</div><div><br></div><div><b>PHYL-GCA_data.csv</b> - Gut content data (GCA) detailing <i>P. hansoni</i> in individual killifsh catches:</div></div></div><div><b>(stream, reach, fish.SC, HCW </b>see above)<br></div><div><b>- fish.size: </b>fish size in mm</div><div><b>- success: </b>1 = <i>P. hansoni</i> present, 0 = <i>P. hansoni</i> not present</div><div><b>- failure: </b>1 = <i>P. hansoni</i> not present, 0 = <i>P. hansoni</i> present</div><div><b>- instar: </b>instar size class - Juvenile = J, Small = S, Medium = M, Large = L, and Extra-Large = XL</div><div><br></div><div><div>___</div><div><br></div><div><b>Stoker-PHYL.R - </b>R code for analysis of data files listed above</div></div

Decomposition of terrestrial resource subsidies in headwater streams: Does consumer diversity matter?

<p>Resource subsidies and biodiversity are essential for maintaining community structure and ecosystem functioning, but the relative importance of consumer diversity and resource characteristics to decomposition remains unclear. Forested headwater streams are detritus-based systems, dependent on leaf litter inputs from adjacent riparian ecosystems, and decomposition of these resources is an important ecosystem function. Here, we examined the effects of consumer community diversity on leaf decomposition in a reciprocal transplant experiment. We asked (1) whether stream consumer communities are adapted to local resources and (2) how functional trait diversity among communities affects the leaf decomposition process. We did not find evidence that communities were adapted to locally derived resource subsidies. Instead, we found that consumer biomass and functional trait diversity as well as resource characteristics were the primary biotic drivers of decomposition. Consumer biomass was stimulated by specific resource subsidies, leading to direct and indirect effects of resource subsidies on ecosystem functioning. Contrary to current theory, we show that decomposition was higher with decreased detritivore functional diversity, suggesting dominant traits encompassing a specific niche increased decomposition. We also show that top-down, consumer diversity effects can be equal in magnitude to the bottom-up effects of resource characteristics during the decomposition process. Our research illustrates the importance of considering multiple biotic and abiotic drivers interacting via multiple pathways to affect a crucial ecosystem function.</p><br><p></p

Mechanisms Underlying Lack of Functional Compensation by Insect Grazers After Tadpole Declines in a Neotropical Stream

Resilience of ecosystems to the sudden decline of large-bodied species is dependent on characteristics of surviving guild members. However, that response may also be mediated by local habitat conditions. Here, we examine the mechanisms behind the observed lack of functional compensation in the algal-grazing guild by insect grazers following the decline of tadpole grazers in a forested Panamanian stream. We examined: (1) shifts to the individual size distribution of insect grazers between pre- and post-tadpole declines in pool and riffle habitats; (2) tadpole and insect preferences for small-, medium-, and large-sized diatoms; and (3) a causal explanation for why insects did not functionally compensate for tadpole declines. The size distribution of insect grazers following tadpole declines differed between habitats, becoming uniform in pools and more right skewed toward a smaller size class in riffles. In both habitats, tadpoles selectively consumed medium-sized diatoms but avoided the largest-sized diatoms. In contrast, grazing insects selectively consumed small-sized diatoms, but switched to medium-sized diatoms after tadpole declines. Tadpole declines led to the loss of the strongest interactions between consumers and diatoms. Smaller-bodied grazing insects could not duplicate these interactions, even with a shift in resource use, providing an explanation for the lack of functional compensation. Furthermore, tadpole declines led to different community structures in each habitat indicating that local habitat conditions mediated the response of surviving guild members. This suggests that the sudden decline of a large-bodied species does not lead to a singular outcome for the surviving community

The Mycobacterium tuberculosis ino1 gene is essential for growth and virulence.

Inositol is utilized by Mycobacterium tuberculosis in the production of its major thiol and of essential cell wall lipoglycans. We have constructed a mutant lacking the gene encoding inositol-1-phosphate synthase (ino1), which catalyses the first committed step in inositol synthesis. This mutant is only viable in the presence of extremely high levels of inositol. Mutant bacteria cultured in inositol-free medium for four weeks showed a reduction in levels of mycothiol, but phosphatidylinositol mannoside, lipomannan and lipoarabinomannan levels were not altered. The ino1 mutant was attenuated in resting macrophages and in SCID mice. We used site-directed mutagenesis to alter four putative active site residues; all four alterations resulted in a loss of activity, and we demonstrated that a D310N mutation caused loss of the active site Zn2+ ion and a conformational change in the NAD+ cofactor

Paisaje, asentamiento y Edad Media: reflexiones sobre dos estudios recientes

[EN] This article reviews two books on the historical development of medieval landscapes and settlement in Brittany and England, and goes on to reflect on the state of research in this field in the Spanish region of Castilla y León[ES] Este artículo parte de la crítica de dos libros sobre el asentamiento y los paisajes medievales en Bretaña (Francia) e Inglaterra para formular algunas reflexiones teóricas y metodológicas sobre el estado de este tipo de investigaciones en Castilla y León.Peer reviewe