Biology subjects

Peck, M.

Publications and source records attributed to Peck, M..

3 recordsLinked to original sources

bioRxiv2021

Evidence for alternate stable states in an Ecuadorian Andean Cloud Forest

We analyzed a set of historical data from rapid vegetation inventories in a tropical montane cloud forest in northern Andean Ecuador. Trees in plots from several types of forest were counted and measured, including: (1) primary forest, including mature and recently closed-canopy sites and naturally formed gaps, (2) abandoned pasture, and (3) intensively-farmed sites. The goal of the study was to understand in a specific period of time the similarities and differences among natural and anthropogenic disturbances and their potential long term effect on the forest plant community. We found that mature and intermediate close canopy sites are similar. Also old forest is quite resilient to gap-forming disturbance. Natural gaps are quickly colonized by old-forest-associated plant species, and return to an old-forest-type community of trees in a short time. In contrast, forests regenerating from anthropogenic disturbance appear to have multiple possible states: some regenerating forest sites where the anthropogenic disturbance were low are coming to closely resemble old-forest-type communities, but some where the anthropogenic disturbance was intense appear to be changing in a very different direction, which does not resemble any other vegetation community type currently in the forest. A major predictor of present ecological state is the type of land use before reforestation: pastures can occasionally transition back to the pre-disturbance state of forest. More intensively used sites, many of which are abandoned sugar cane plantations, do not return to a pre-disturbance ecological state, instead forming a new and different kind of forest, dominated by a different community of trees. We examined tree-seedling communities to understand the trajectory of the forest into the future, and find that new forest types may be forming that do not resemble any existing associationsintensive agricultural sites. We also found that Los Cedros is extremely diverse in tree species. We estimate approximately 500 species of tree in only the small southeastern area of the reserve that has been explored scientifically. Additionally, the forest tree community shows extremely rapid distance decay (beta-diversity), approaching near complete turn-over in the limited spatial extent of the study. This suggests that hundreds of other tree species remain to be observed in the reserve, in addition to the 350+ that are directly observed in the present study, including new observations of species with IUCN threatened-endangered status. We also highlight the conservation value of Reserva Los Cedros, which has managed to reverse deforestation within its boundaries despite a general trend of extensive deforestation in the surrounding region, and to protect large, contiguous areas of highly-endangered Andean primary cloud forest habitat.

ecology↗

bioRxiv2021

Transgenerational effects decrease larval resilience to ocean acidification and warming but juvenile European sea bass could benefit from higher temperatures in the NE Atlantic

1.The aim of this study was to investigate the effect of ocean acidification (OA) and warming (OW) as well as the transgenerational effect of OA on larval and juvenile growth and metabolism of a large economically important fish species with a long generation time. Therefore we incubated European sea bass from Brittany (France) for two generations (>5 years in total) under current and predicted OA conditions (PCO2: 650 and 1700 {micro}atm). In the F1 generation both OA condition were crossed with OW (temperature: 15-18{degrees}C and 20-23{degrees}C). We found that OA alone did not affect larval or juvenile growth and OW increased developmental time and growth rates, but OAW decreased larval size at metamorphosis. Larval routine metabolic rate (RMR) and juvenile standard metabolic rate (SMR) were significantly lower in cold compared to warm conditioned fish and also lower in F0 compared to F1 fish. We did not find any effect of OA on RMR or SMR. Juvenile PO2crit was not affected by OA, OW or OAW in both generations. We discuss the potential underlying mechanisms resulting in beneficial effects of OW on F1 larval growth and RMR and in resilience of F0 and F1 larvae and juveniles to OA, but on the other hand resulting in vulnerability of F1, but not F0 larvae to OAW.. With regard to the ecological perspective, we conclude that recruitment of larvae and early juveniles to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures. Summary statementWe found that OA did not affect developmental time, growth, RMR and SMR, while OW increased these traits. OAW decreased larval size at metamorphosis. We discuss underlying mechanisms and the ecological perspective resulting from these results and conclude that recruitment to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures in Atlantic waters.

physiology↗

bioRxiv2017

Natural selection shaped the rise and fall of passenger pigeon genomic diversity

The extinct passenger pigeon was once the most abundant bird in North America, and possibly the world. While theory predicts that large populations will be more genetically diverse and respond more efficiently to selection, passenger pigeon genetic diversity was surprisingly low. To investigate this we analysed 41 mitochondrial and 4 nuclear genomes from passenger pigeons, and 2 genomes from band-tailed pigeons, passenger pigeons closest living relatives. We find that passenger pigeons large population size allowed for faster adaptive evolution and removal of harmful mutations, but that this drove a huge loss in neutral genetic diversity. These results demonstrate how great an impact selection can have on a vertebrate genome, and invalidate previous results that suggested population instability contributed to this species surprisingly rapid extinction.

genomics↗