The reorganization of predator–prey networks over 20 million years explains extinction patterns of mammalian carnivoresNascimento, João C. S.; Blanco, Fernando; Domingo, M. Soledad; Cantalapiedra, Juan L.; Pires, Mathias M.
doi: 10.1111/ele.14448pmid: 38814285
Linking the species interactions occurring at the scale of local communities to their potential impact at evolutionary timescales is challenging. Here, we used the high‐resolution fossil record of mammals from the Iberian Peninsula to reconstruct a timeseries of trophic networks spanning more than 20 million years and asked whether predator–prey interactions affected regional extinction patterns. We found that, despite small changes in species richness, trophic networks showed long‐term trends, gradually losing interactions and becoming sparser towards the present. This restructuring of the ecological networks was driven by the loss of medium‐sized herbivores, which reduced prey availability for predators. The decrease in prey availability was associated with predator longevity, such that predators with less available prey had greater extinction risk. These results not only reveal long‐term trends in network structure but suggest that prey species richness in ecological communities may shape large scale patterns of extinction and persistence among predators.
Caloric restriction extends lifespan in a clonal plantChmilar, Suzanne L.; Luzardo, Amanda C.; Dutt, Priyanka; Pawluk, Abbe; Thwaites, Victoria C.; Laird, Robert A.
doi: 10.1111/ele.14444pmid: 38814322
When subjected to dietary caloric restriction (CR), individual animals often outlive well‐fed conspecifics. Here, we address whether CR also extends lifespan in plants. Whereas caloric intake in animals comes from ingestion, in plants it derives from photosynthesis. Thus, factors that reduce photosynthesis, such as reduced light intensity, can induce CR. In two lab experiments investigating the aquatic macrophyte Lemna minor, we tracked hundreds of individuals longitudinally, with light intensity—and hence, CR—manipulated using neutral‐density filters. In both experiments, CR dramatically increased lifespan through a process of temporal scaling. Moreover, the magnitude of lifespan extension accorded with the assumptions that (a) light intensity positively relates to photosynthesis following Michaelis–Menten kinetics, and (b) photosynthesis negatively relates to lifespan via a power law. Our results emphasize that CR‐mediated lifespan extension applies to autotrophs as well as heterotrophs, and suggest that variation in light intensity has quantitatively predictable effects on plant aging trajectories.
Heterogenous effects of bat declines from white‐nose syndrome on arthropodsWray, Amy K.; Peery, Marcus Z.; Kochanski, Jade M.; Pelton, Emma; Lindner, Daniel L.; Gratton, Claudio
doi: 10.1111/ele.14437pmid: N/A
In North America, white‐nose syndrome (WNS) has caused precipitous declines in hibernating bat populations, raising the question of whether the rapid loss of arthropodivorous bats may affect the abundance of their prey. During the summers of 2015–2018 (1 year after the arrival of WNS in Wisconsin, USA), we performed intensive arthropod black‐light trapping, ultrasonic acoustic monitoring, and emergence counts at 10 little brown (Myotis lucifugus) and big brown (Eptesicus fuscus) bat maternity roosts with paired control sites. For little brown bats, which are severely affected by WNS, roost counts declined by 95% over the four‐year period, compared to a 38% decline in big brown bat roost counts. Total arthropod abundance decreased by 49%, although decreases among common little brown bat prey were less severe. Our natural predator exclusion experiment supports existing evidence that bats can have measurable trophic impacts on arthropod communities, primarily via top‐down effects on common prey.
Temporal dynamics of Grime's CSR strategies in plant communities during 60 years of successionZhang, Yan‐song; Meiners, Scott J.; Meng, Yani; Yao, Qi; Guo, Kun; Guo, Wen‐Yong; Li, Shao‐peng
doi: 10.1111/ele.14446pmid: 38814284
Grime's competitive, stress‐tolerant, ruderal (CSR) theory predicts a shift in plant communities from ruderal to stress‐tolerant strategies during secondary succession. However, this fundamental tenet lacks empirical validation using long‐term continuous successional data. Utilizing a 60‐year longitudinal data of old‐field succession, we investigated the community‐level dynamics of plant strategies over time. Our findings reveal that while plant communities generally transitioned from ruderal to stress‐tolerant strategies during succession, initial abandonment conditions crucially shaped early successional strategies, leading to varied strategy trajectories across different fields. Furthermore, we found a notable divergence in the CSR strategies of alien and native species over succession. Initially, alien and native species exhibited similar ruderal strategies, but in later stages, alien species exhibited higher ruderal and lower stress tolerance compared to native species. Overall, our findings underscore the applicability of Grime's predictions regarding temporal shifts in CSR strategies depending on both initial community conditions and species origin.
The unexpected influence of legacy conspecific density dependenceMagee, Lukas J.; LaManna, Joseph A.; Wolf, Amy T.; Howe, Robert W.; Lu, Yuanming; Valle, Denis; Smith, Daniel J. B.; Bagchi, Robert; Bauman, David; Johnson, Daniel J.
doi: 10.1111/ele.14449pmid: 38857318
When plants die, neighbours escape competition. Living conspecifics could disproportionately benefit because they are freed from negative intraspecific processes; however, if the negative effects of past conspecific neighbours persist, other species might be advantaged, and diversity might be maintained through legacy effects. We examined legacy effects in a mapped forest by modelling the survival of 37,212 trees of 23 species using four neighbourhood properties: living conspecific, living heterospecific, legacy conspecific (dead conspecifics) and legacy heterospecific densities. Legacy conspecific effects proved nearly four times stronger than living conspecific effects; changes in annual survival associated with legacy conspecific density were 1.5% greater than living conspecific effects. Over 90% of species were negatively impacted by legacy conspecific density, compared to 47% by living conspecific density. Our results emphasize that legacies of trees alter community dynamics, revealing that prior research may have underestimated the strength of density dependent interactions by not considering legacy effects.
Frequency‐dependent tolerance to aircraft disturbance drastically alters predicted impact on shorebirdsKolk, Henk‐Jan; Smit, Cor J.; Allen, Andrew M.; Ens, Bruno J.; Pol, Martijn
doi: 10.1111/ele.14452pmid: 38857324
Anthropogenic disturbance of wildlife is increasing globally. Generalizing impacts of disturbance to novel situations is challenging, as the tolerance of animals to human activities varies with disturbance frequency (e.g. due to habituation). Few studies have quantified frequency‐dependent tolerance, let alone determined how it affects predictions of disturbance impacts when these are extrapolated over large areas. In a comparative study across a gradient of air traffic intensities, we show that birds nearly always fled (80%) if aircraft were rare, while birds rarely responded (7%) if traffic was frequent. When extrapolating site‐specific responses to an entire region, accounting for frequency‐dependent tolerance dramatically alters the predicted costs of disturbance: the disturbance map homogenizes with fewer hotspots. Quantifying frequency‐dependent tolerance has proven challenging, but we propose that (i) ignoring it causes extrapolations of disturbance impacts from single sites to be unreliable, and (ii) it can reconcile published idiosyncratic species‐ or source‐specific disturbance responses.
Climate change fluctuations can increase population abundance and range sizeMacDonald, Jane Shaw; Lutscher, Frithjof; Bourgault, Yves
doi: 10.1111/ele.14453pmid: 38844411
Climate change threatens many species by a poleward/upward movement of their thermal niche. While we know that faster movement has stronger impacts, little is known on how fluctuations of niche movement affect population outcomes. Environmental fluctuations often affect populations negatively, but theory and experiments have revealed some positive effects. We study how fluctuations around the average speed of the niche impact a species' persistence, abundance and realized niche width under climate change. We find that the outcome depends on how fluctuations manifest and what the relative time scale of population growth and climate fluctuations are. When populations are close to extinction with the average speed, fluctuations around this average accelerate population decline. However, populations not yet close to extinction can increase in abundance and/or realized niche width from such fluctuations. Long‐lived species increase more when their niche size remains constant, short‐lived species increase more when their niche size varies.