scholarly journals Ontogenetic niche shifts in a locally endangered tree species (Olea europaea subsp. cuspidata) in a disturbed forest in Northern Ethiopia: Implications for conservation

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256843
Author(s):  
Mekdes Ourge Wegasie ◽  
Kari Klanderud ◽  
Ørjan Totland ◽  
Katrine Eldegard
Keyword(s):  
Species Richness ◽  
Human Disturbance ◽  
Woody Species ◽  
Conservation Strategies ◽  
Life Stages ◽  
Endangered Tree ◽  
Endangered Tree Species ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche

Understanding the responses of different ontogenetic stages to environmental and human disturbance factors is essential for developing efficient conservation strategies for endangered plant species. We examined how three ontogenetic stages of a locally endangered tree species, Olea europaea subsp. cuspidata, responded to environmental factors and human disturbance in Hugumburda dry Afromontane forest in Ethiopia. We counted individual seedlings, saplings and adults of O. europaea in 70 20 × 20 m quadrats over ca. 2.8 ha, and measured biotic (woody species richness, canopy cover, aboveground tree biomass, herbaceous cover), abiotic (soil and topographic variables), and human disturbance factors (logging and tracks). To detect ontogenetic niche shifts, we compared observed vs. simulated locations of trees in the three life stages and how they related to the environmental and human disturbance factors. We found that the population structure of O. europaea showed generally low recruitment, with few seedlings per hectare compared with the abundance of saplings and adults. The probability of finding O. europaea individuals was influenced by biotic (woody species richness) and abiotic (soil depth, slope) environmental conditions and human disturbance (logging intensity), but the direction, strength and shape of the relationships differed between seedling, sapling and adult life stages, indicating ontogenetic niche shifts. All life stages showed a positive relationship with elevation. The observed environmental niches of the different lifestages of O. europaea, and their association with human disturbance levels, should be considered when conservation strategies are developed for this species. Human disturbance in terms of logging decreases the abundance of saplings, but may facilitate emerging seedlings through creation of gaps with improved light conditions. Recruitment is, however, very low in the study area, and seedlings should be protected from browsing to enhance survival. Woody species richness in general should be conserved to optimize conditions also for O. europaea saplings.

Locally endangered tree species in a dry montane forest are enhanced by high woody species richness but affected by human disturbance

2018 ◽  
Vol 158 ◽  
pp. 19-27
Author(s):  
Mekdes Ourge Wegasie ◽  
Katrine Eldegard ◽  
Kari Klanderud ◽  
Sarah Tewolde-Berhan ◽  
Kidane Giday ◽  
...  
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Human Disturbance ◽  
Woody Species ◽  
Montane Forest ◽  
Endangered Tree ◽  
Endangered Tree Species

scholarly journals Predation and associational refuge drive ontogenetic niche shifts in an arctiid caterpillar

Ecology ◽  
2015 ◽  
Vol 96 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Patrick Grof-Tisza ◽  
Marcel Holyoak ◽  
Edward Antell ◽  
Richard Karban
Keyword(s):  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
Associational Refuge

Ontogenetic Niche Shifts, Predators, and Coexistence among Consumer Species

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Alternative Stable States ◽  
Niche Partitioning ◽  
Stage Structure ◽  
Stable States ◽  
Stable Coexistence ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
Dependent Growth ◽  
Equal Population

This chapter considers how stage structure and ontogenetic niche shifts may affect the coexistence between two consumer species competing for two resources in the absence and presence of predators, and how ontogenetic niche shifts may give rise to alternative stable states. More specifically, the analysis will use techniques developed within the consumer-resource framework of Tilman (1982), including consumption and renewal vectors (Schellekens, de Roos, and Persson 2010). Tilman showed that stable coexistence between consumers feeding on the same two resources is possible if each consumer species feeds proportionally more on the resource that limits its own growth most. Stable coexistence is, however, also affected by the form of resource-dependent growth isoclines, which represent combinations of resource densities that lead to equal population growth of consumers. It is shown that ontogenetic niche shifts per se affect the form of resource-dependent growth isoclines, which in turn may lead to coexistence through niche partitioning. The chapter also discusses how predation may promote the performance of a species undergoing ontogenetic niche shifts even in the case where it is both the inferior competitor and the preferred prey of the predator.

Summary

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Population Dynamics ◽  
Life History ◽  
General Framework ◽  
Community Effects ◽  
Present Volume ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Different Types ◽  
Emergent Community ◽  
Ontogenetic Niche

This chapter provides a summary of the topics covered by the present volume. The summary serves the purpose of clearly showing how different chapters fit together in a general framework with respect to model approaches as well as results obtained. Reading this summary chapter will show readers the different types of community modules that will be analyzed as well as provide a clear impression of the results and insights that presented in this book. Topics discussed include biomass overcompensation, ontogenetic (a)symmetry in energetics, emergent community effects of biomass overcompensation, ontogenetic niche shifts in consumer life history, ontogenetic niche shifts in predator life history, competition between consumers with and without ontogenetic niche shifts, and ontogenetic (a)symmetry in energetics and population dynamics.

scholarly journals Predicting coexistence in species with continuous ontogenetic niche shifts and competitive asymmetry

Ecology ◽  
2017 ◽  
Vol 98 (11) ◽  
pp. 2823-2836 ◽  
Author(s):  
Ronald D. Bassar ◽  
Joseph Travis ◽  
Tim Coulson
Keyword(s):  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche

scholarly journals Prey size of salmonid fishes in streams, lakes, and oceans

2001 ◽  
Vol 58 (6) ◽  
pp. 1122-1132 ◽  
Author(s):  
Ernest R Keeley ◽  
James WA Grant
Keyword(s):  
Growth Rate ◽  
Prey Size ◽  
Growth Potential ◽  
Salmonid Fishes ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
The Difference

The growth rate of salmonid fishes is typically fastest in oceans, intermediate in lakes, and slowest in streams. We compiled literature data to test whether differences in the size of prey eaten by salmonids in the three habitats could account for these differences in growth rate (i.e., the prey-size hypothesis). In all three habitats, salmonid fishes exhibited ontogenetic niche shifts from feeding primarily on invertebrates when small to feeding on fishes when large. Contrary to the prey-size hypothesis, invertebrates eaten in streams were larger than those eaten in lakes or oceans, whereas fish eaten in oceans were smaller than those eaten in streams or lakes. Consistent with the prey-size hypothesis, salmonids began eating fish at a smaller size in oceans (8 cm) than in lakes (15 cm) or streams (27 cm). However, the size at which salmonids became predominantly piscivorous (31 cm) did not differ significantly between habitats. We suggest that the difference in growth potential between the three habitats is partly related to the size at which fish first enter the diet.

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