Lecture 11 - Ecology Studyguide PDF

1.x = age of individuals: This represents the age of individuals within a population. It's a variable used to denote different age categories or classes within the population. 2.nx = number of individuals of age x: This term refers to the number of individuals present in the population at a specific...

1.x = age of individuals: This represents the age of individuals within a population. It's a variable used to denote different age categories or classes within the population. 2.nx = number of individuals of age x: This term refers to the number of individuals present in the population at a specific age x. It's essentially a count of how many individuals are at a particular stage of their life cycle. 3.bx = age-specific births (mean # F born to a F of age x): This represents the average number of offspring produced by a female individual of age x during a specific time period. It's a measure of reproductive output specific to each age class. 4.sx = proportion survivorship to the next age class: This is the proportion of individuals in a particular age class that survive to the next age class. It's a measure of how likely individuals are to survive from one age group to the next. 5.∑bx = gross reproductive rate: This term represents the total reproductive output of the population summed across all age classes. It's calculated by summing up the age-specific birth rates (bx) for all age classes. 6.N(t) = total number of individuals in a population in year t: This is the total population size at a specific point in time, usually denoted as "t" representing time. 7.λ - finite multiplication rate = N(t+1)/N(t) = er r = ln(λ): This is a measure of the population's growth rate over a defined time interval. It's calculated by dividing 1 the population size at one time point (t+1) by the population size at the previous time point (t). In continuous time models, it's often represented as the natural logarithm of λ, where λ is the finite multiplication rate, and "r" is the intrinsic rate of natural increase. Exponential Growth Model (r-selected traits): r: Intrinsic rate of population growth. It's calculated as the difference between the birth rate (b) and the death rate (d). This model is often associated with species that exhibit r-selected traits, meaning they prioritize high reproductive rates (lots of offspring produced in a short time) over parental care or competition for limited resources. In an exponential growth model, population growth is described by the equation: N(t)=N(0)∗ertN(t)=N(0)∗ert Where:N(t)N(t) = population size at time ttN(0)N(0) = initial population sizerr = intrinsic rate of population growthtt = timeThis model assumes unlimited resources and a constant intrinsic growth rate, leading to unbounded growth over time. It's a theoretical model and doesn't account for factors like environmental limitations or competition. Logistic Growth Model (K-selected traits): K: Population carrying capacity. It represents the maximum number of individuals that a habitat can support sustainably. This model is associated with species that exhibit K-selected traits, meaning they prioritize quality over quantity in offspring, often with strong parental care and adaptations to compete for limited resources. In a logistic growth model, population growth is described by the equation: dNdt=rN(1−NK)dtdN=rN(1−KN) Where:dNdtdtdN = rate of change of population size over timerr = intrinsic rate of population growthNN = current population sizeKK = population carrying capacityThis model incorporates environmental constraints by assuming that as the population approaches the carrying capacity (KK), growth slows down and eventually levels off. The rate of population growth decreases as the population size approaches the carrying capacity due to factors like competition for resources and limited space.These two models represent different strategies in population growth and reflect the trade-offs between reproduction and survival strategies in different species. 1 Carrying capacity (K): Definition: Carrying capacity refers to the maximum number of individuals of a species that a particular habitat or environment can sustainably support over the long term. It's influenced by factors such as availability of resources (food, water, shelter), competition, predation, disease, and environmental conditions. Logistic Growth Model: In the logistic growth model, carrying capacity (KK) is a key parameter that represents the point at which the population growth rate levels off as the population size approaches the maximum sustainable level for the given environment.Maximum growth rate & maximum sustainable yield: Maximum Growth Rate: This refers to the highest rate at which a population can grow under ideal conditions, typically when resources are abundant and there are no limiting factors such as predation or competition. It's often denoted by the parameter rr (intrinsic rate of population growth) in population growth models like the exponential growth model.Maximum Sustainable Yield (MSY): MSY is the maximum amount of a renewable resource that can be harvested without compromising the long-term sustainability of the resource or the ecosystem. It's an important concept in fisheries management, forestry, and wildlife management, aiming to find a balance between resource extraction and conservation.Minimum viable population (MVP): Definition: MVP refers to the smallest population size of a species that can persist 2 over the long term in its natural habitat without facing extinction. It takes into account factors such as genetic variation, demographic stochasticity, environmental variability, and catastrophes. Maintaining populations above the MVP is crucial for preventing extinction and preserving biodiversity. Importance: MVP is a critical concept in conservation biology and management, guiding efforts to establish and maintain viable populations of endangered or threatened species. Minimum dynamic area: Definition: Minimum dynamic area (MDA) refers to the smallest habitat area required to support a viable population of a species over time. It considers factors such as habitat quality, connectivity, resource availability, and population dynamics. MDA assessments help determine habitat conservation priorities, identify critical areas for species survival, and guide land-use planning and management efforts. Importance: Protecting and managing areas above the MDA is essential for ensuring the long-term persistence of species and maintaining ecosystem functioning and biodiversity. These concepts are fundamental in ecology, conservation biology, and natural resource management, providing insights into population dynamics, sustainable resource use, and biodiversity conservation. 2 Carrying capacity (KK) is the maximum number of individuals of a species that a particular habitat or environment can sustainably support over the long term. It represents the equilibrium population size where the birth rate equals the death rate, resulting in zero population growth. In ecological terms, it's the point at which the environment's resources can support the population without degradation or depletion.In the context of sustainable resource management, the maximum sustainable yield (MSY) is the maximum amount of a renewable resource that can be harvested without compromising the long-term sustainability of the resource or the ecosystem. It's typically targeted as a goal for fisheries management, forestry, and wildlife management to ensure that resources are utilized efficiently while maintaining ecosystem health and resilience. The relationship between carrying capacity (KK) and the maximum sustainable yield (MSYMSY) depends on the specific resource and ecosystem dynamics. In many cases, the maximum sustainable yield is targeted at a population size below the carrying capacity. This is because harvesting at the carrying capacity can lead to negative impacts such as overexploitation, ecosystem degradation, and reduced resilience to environmental changes.Instead, sustainable resource management aims to harvest at a level that allows the population to remain above a certain threshold, ensuring the population's long-term viability while still providing a sustainable yield. This threshold 3 may be above the minimum viable population size to maintain genetic diversity and ecosystem functioning. Therefore, the population size (NN) targeted for maximum sustainable yield varies depending on factors such as the species' life history, population dynamics, habitat quality, and management objectives. It's often determined through scientific assessments, modeling, and adaptive management approaches that consider both ecological and socioeconomic factors. 3 Let's break down the relationships between Minimum Viable Population (MVP), Minimum Dynamic Area (MDA), and different types of animals, considering the provided criteria: 1.Large carnivores: 1. MVP: Since large carnivores typically have lower population densities compared to herbivores due to their position higher up in the food chain, their Minimum Viable Population (MVP) might be close to or slightly above 1000 individuals. 2. MDA: Despite having a smaller population size, large carnivores often require larger home ranges or territories to meet their hunting and ranging needs. Therefore, their Minimum Dynamic Area (MDA) might be relatively large compared to the MVP. This could translate to hundreds or even thousands of square kilometers of habitat area per individual or per breeding pair, depending on factors like prey availability, habitat quality, and human disturbances. 2.Large herbivores: 1. MVP: Large herbivores typically exist in larger populations compared to large carnivores due to their lower trophic level and ability to utilize abundant plant resources. However, their MVP might still be around 1000 4 individuals, depending on the species and its ecological requirements. 2. MDA: Large herbivores, despite having larger populations, also require extensive areas of habitat to support their foraging and ranging needs. Their MDA might be similar to or even larger than that of large carnivores, encompassing hundreds to thousands of square kilometers of suitable habitat. This allows for maintaining viable populations and supporting natural behaviors such as seasonal migrations and territoriality. 1.Small herbivores: 1. MVP: Small herbivores often have higher population densities compared to large herbivores and carnivores due to their smaller body size, shorter generation times, and faster reproductive rates. However, their MVP might still be around 1000 individuals to ensure genetic diversity and population resilience. 2. MDA: Despite having smaller individual home ranges, small herbivores may still require substantial habitat areas to support their populations, especially in environments with high predation pressure or limited resources. Their MDA might be smaller compared to large herbivores and carnivores but could still range from several to tens of square kilometers per individual, depending on factors like habitat quality, predation risk, and population dynamics. In summary, while large carnivores may have smaller individual populations compared to large herbivores, they often require larger habitat areas per individual due to their wide-ranging behavior and lower population densities. Conversely, small herbivores may have higher population densities but still require adequate habitat areas to support their populations and maintain ecological balance within their ecosystems. 4 ChatGPT ChatGPT To determine which populations of bighorn sheep to prioritize for conservation efforts, several factors should be considered, including population size, genetic diversity, habitat quality, connectivity, and conservation status. Here's an approach to making this decision: 1.Evaluate Population Sizes: Assess the population sizes of the six geographically isolated bighorn sheep populations (N = 10, 23, 55, 86, 106, and 200). Larger populations generally have higher resilience to environmental stochasticity and are less prone to demographic and genetic risks associated with small population sizes. 2.Consider Genetic Diversity: Genetic diversity is crucial for the long-term viability of populations as it enhances their adaptive potential to environmental changes and reduces the risk of inbreeding depression. Assess the genetic diversity of each population, considering factors such as effective population size and genetic structure. 3.Assess Habitat Quality and Connectivity: Evaluate the habitat quality of each population's habitat area, including factors such as food availability, water sources, shelter, and habitat fragmentation. Connectivity between populations is also 5 important for genetic exchange and maintaining demographic viability. 4. Review Conservation Status and Threats: Consider the conservation status of each population and the primary threats they face, such as habitat loss, fragmentation, disease, predation, and human disturbance. Prioritize populations that are at higher risk or facing imminent threats. 5.Select Priority Populations: Based on the above considerations, prioritize the populations that: 1. Have larger population sizes (e.g., 200, 106, and 86 individuals) to ensure demographic resilience. 2. Exhibit higher genetic diversity and lower risks of inbreeding (if genetic data is available). 3. Occupy high-quality habitat areas with sufficient resources and minimal anthropogenic disturbances. 4. Are connected to other populations or have potential for habitat restoration and connectivity enhancement. Given the provided population sizes (N = 10, 23, 55, 86, 106, and 200), the populations with 200, 106, and 86 individuals appear to be the largest and may represent the best candidates for conservation investment. However, it's essential to conduct a more detailed assessment considering all factors mentioned above to make a well-informed decision on which three populations to prioritize for conservation efforts. 5 Intraspecific competition - definition and consequences: Definition: Intraspecific competition refers to the competition for resources (such as food, water, shelter, or mates) among individuals of the same species. It occurs when resources are limited, leading to individuals within the population competing with one another for access to these resources. Consequences: Intraspecific competition can have several consequences: Reduced growth and reproduction: Individuals experiencing competition may have limited access to essential resources, resulting in decreased growth rates and reproductive success. Increased mortality: Intense competition can lead to higher mortality rates as individuals struggle to obtain necessary resources for survival. Changes in behavior: Competition can influence behaviors such as foraging, territoriality, and social interactions as individuals attempt to gain an advantage over rivals. Population dynamics: Intraspecific competition can influence population dynamics by affecting birth rates, death rates, and overall population size. It can contribute to population regulation and density-dependent effects. Population regulation scenarios (how b and d change with N): Population regulation refers to the processes that maintain the population size of a 6 species within a certain range. This regulation often involves changes in birth rates (bb) and death rates (dd) as the population size (NN) changes. Here are different scenarios:Scenario 1: Density-independent regulation: In density-independent regulation, birth and death rates are not influenced by population density. Birth rates (bb) and death rates (dd) remain constant regardless of population size (NN).Factors such as weather events, natural disasters, or habitat destruction can affect population size independently of density.Scenario 2: Density-dependent regulation: In density-dependent regulation, birth and death rates are influenced by population density. As population size (NN) increases, birth rates (bb) may decrease due to factors such as resource competition, limited space, or increased predation.Conversely, death rates (dd) may increase with population size due to factors such as increased disease transmission, food scarcity, or heightened intraspecific competition.Density-dependent regulation often leads to a stabilizing effect on population size, with birth and death rates adjusting to maintain the population near a carrying capacity (KK).Density-dependent and density-independent: Density-dependent factors: These are environmental factors that influence population dynamics in relation to population density. Examples include competition for resources, predation, disease transmission, and territoriality. As population density increases, the effects of these factors become more pronounced, leading to changes in birth rates, death rates, and population size. Density-independent factors: These are environmental factors that affect population dynamics regardless of population density. Examples include weather events (such as hurricanes or droughts), natural disasters (such as wildfires or floods), habitat destruction, and pollution. These factors can have immediate and often severe impacts on populations, irrespective of their size. 6 Consequences of Intraspecific Competition: 1.Growth: Intraspecific competition can significantly impact the growth of individuals within a population. When resources become limited due to competition, individuals may experience reduced access to essential nutrients or energy sources, leading to slower growth rates compared to individuals in less competitive environments. 2.Behavior: Intraspecific competition can also influence the behavior of individuals within a population. Competition for resources may lead to changes in foraging behavior, territoriality, social interactions, and reproductive strategies as individuals attempt to maximize their access to essential resources and minimize conflicts with competitors. Regarding your questions: Growth is density-dependent. Intraspecific competition affects growth rates, with individuals in denser populations experiencing more intense competition for resources, resulting in reduced growth rates compared to individuals in less crowded populations. Activity is most variable at 70 added competitors. This statement implies that activity levels (which could include behaviors such as foraging, movement, or social interactions) show the highest variability when 70 additional competitors are introduced, suggesting that this level of competition has a significant impact on 7 individual behavior within the population. 7 1.Monarch eggs with lower density on plants have a higher probability of survival. When there are fewer eggs per plant, there is less competition for resources like food and space, which increases the chances of individual eggs surviving to hatch and develop into larvae. 2.If eggs have a density of 5 per plant, those monarchs have a predicted survival probability of 95%. Lower density reduces intraspecific competition, allowing a higher proportion of eggs to survive to maturity. 3.This is an example of density dependence. The survival probability of the monarch eggs is influenced by the density of eggs per plant, indicating that intraspecific competition affects mortality rates in a density-dependent manner. 8 Intraspecific competition, often illustrated through population density and food availability, can have significant consequences for mortality rates within a population. Here's how: 1.Population Density: 1. High Population Density: When population density is high, individuals within the population may experience increased competition for resources such as food, shelter, and territory. This heightened competition can lead to higher mortality rates due to individuals being unable to obtain sufficient resources for survival. 2. Low Population Density: Conversely, when population density is low, individuals may have better access to resources with less competition. This can result in lower mortality rates as individuals are more likely to meet their basic survival needs. 2.Food Availability: 1. Limited Food Availability: In environments with limited food availability, intraspecific competition for food can be intense. Individuals may face starvation or malnutrition if they are unable to access enough food to sustain themselves. This can lead to increased mortality rates, particularly among weaker or less competitive individuals. 9 2. Abundant Food Availability: Conversely, in environments with abundant food resources, intraspecific competition for food may be less severe. Individuals are more likely to have access to sufficient food, reducing the risk of mortality due to starvation or malnutrition. Overall, the consequences of intraspecific competition on mortality rates depend on the interplay between population density and food availability. High population density coupled with limited food availability often results in elevated mortality rates, while low population density and abundant food resources tend to lead to lower mortality rates within a population. 9 1.Fewer mature females will give birth when the number (N) of individuals (x=2 or more) is high. Explanation: Intraspecific competition can affect reproduction in several ways. When the population density is high, and competition for resources is intense, individuals may allocate more energy towards survival rather than reproduction. This can result in a reduction in reproductive output, including fewer mature females giving birth. Conversely, in low-density populations with less competition, individuals may allocate more resources towards reproduction, leading to higher reproductive output. Therefore, when the number of individuals (x=2 or more) is high, indicating a high population density, the consequence is fewer mature females giving birth due to increased intraspecific competition for resources. 10 ChatGPT ChatGPT Consequences of Intraspecific Competition: Territory Size & Reproduction 1.Nests found in higher densities are likely to be in smaller territories. Explanation: Intraspecific competition often results in individuals defending smaller territories when population densities are high. As competition for resources such as nesting sites increases, individuals may be forced to occupy smaller territories, leading to higher nest densities within a given area. 2.Birth rates in this population are density- dependent. Explanation: Density-dependent birth rates mean that the reproductive output of individuals within the population is influenced by population density. As population density increases, competition for resources such as food, nesting sites, and mates also increases, which can lead to adjustments in birth rates. Intraspecific competition can result in lower birth rates at higher population densities due to resource limitations and increased competition. 3.We can predict an annual mean clutch size of 7.5 when the density of breeding pairs is 1.0 per hectare. Explanation: This indicates that the clutch size of the population decreases as the 11 density of breeding pairs increases, reflecting density-dependent effects on reproduction. As population density increases, individuals may allocate fewer resources to reproduction, leading to a decrease in clutch size. Therefore, at a density of 1.0 breeding pairs per hectare, the predicted annual mean clutch size is 7.5 eggs per clutch. 11 Vocab 1.Carrying capacity (K): 1. Carrying capacity (K) refers to the maximum population size of a species that a given environment can sustain indefinitely, taking into account factors like available resources, habitat suitability, and interactions with other species. 2.When b = d: 1. When the birth rate (b) equals the death rate (d), the population is in equilibrium, meaning that the number of individuals being born is equal to the number of individuals dying, resulting in zero population growth. 3.Logistic population growth model: 1. In the logistic population growth model, population growth initially follows exponential growth but eventually levels off as it approaches the carrying capacity (K). The relationship between population size (N) and carrying capacity (K) is described by the logistic equation: dN/dt = rN((KN)/K), where r is the intrinsic growth rate and dN/dt represents the rate of change of population size over time. 4.How population models are used in conservation: 1. Population models are used in conservation to understand the dynamics of endangered or threatened species, predict population trends, assess 12 the effectiveness of management strategies, and make informed decisions about conservation priorities and actions. 5. Maximum sustainable yield: 1. Maximum sustainable yield (MSY) is the maximum amount of a renewable resource that can be harvested without depleting the resource or harming the ecosystem's long-term health and productivity. It's a key concept in natural resource management, aiming to balance resource extraction with conservation goals. 6.Minimum viable population: 1. Minimum viable population (MVP) refers to the smallest population size of a species that can persist over the long term without facing extinction. It considers factors like genetic diversity, demographic stochasticity, and environmental variability, guiding conservation efforts to maintain viable populations. 7.Minimum dynamic area: 1. Minimum dynamic area (MDA) is the smallest habitat area required to support a viable population of a species over time. It considers habitat quality, connectivity, and population dynamics, helping identify critical areas for species conservation and habitat management. 8.Competition: Intraspecific: 1. Intraspecific competition refers to competition for resources among individuals of the same species. It can affect population dynamics, behavior, reproduction, and survival within a population. 9.Consequences of intraspecific competition for different life history categories: 1. Intraspecific competition can impact different life history categories (such as growth, reproduction, and mortality) by influencing resource availability, access to mates, and social dynamics within populations. 10.Population Regulation Scenarios: 1. Density-dependent regulation: Birth rates and/or death rates change as population density changes, often due to factors like resource availability or intraspecific competition. 2. Density-independent regulation: Birth rates and death rates remain constant regardless of population density, often due to external factors like weather events or natural disasters. 12