up:: [[CKLA400 - Ecology and Sustainable Landscapes]] tags:: #source/course #on/design #on/landscape_design # CKLA400 M3 - Principles of Landscape Ecology 2 The previous module delved into essential concepts in ecology and landscape ecology, covering [[Ecological Structure]], [[Ecosystem Processes]], [[Ecosystem Dynamics]], and [[Human Influences on Ecosystems]]. These notions include [[Ecotones]], [[Flows and Cycles]], [[Ecological Successions]], [[Landscape Patterns]] such as patches and corridors, and the significance of temporal and spatial scales. These concepts are interconnected and play pivotal roles in understanding landscape sustainability. The *interconnectedness is particularly crucial for grasping the concept of ecological resilience*, which underpins much of landscape sustainability. **Key Points:** - The current module will further explore concepts essential for understanding landscape sustainability, building upon the foundation laid in the previous module. - These concepts are interrelated and interdependent, highlighting the significance of recognizing their interconnectedness in understanding ecological resilience and landscape sustainability. ## Ecosystem Classification (related [[PDC-ADV M2 - Climate Classification Systems]]) Ecosystems occur across various spatial scales, from small entities like rotting logs to the entire globe. Understanding ecosystems involves determining the relevant scale based on the phenomena of interest. To compare or extend ecological knowledge across ecosystems, it's crucial to consider the same spatial scale. Standardized classification systems based on similarities and differences help in making such comparisons. Development of ecosystem classification systems has a long history dating back to Alexander von Humboldt, with ongoing efforts to create globally applicable hierarchical systems. These classification systems face challenges, including uncertainties and the difficulty in recognizing and defining the boundaries of the finest-scale ecosystems. Consequently, classifying higher ecosystem units is more of an intellectual exercise to guide thinking rather than a definitive typology until further research resolves these issues. Despite this, existing ecosystem classifications by organizations like the [[World Wildlife Federation (WWF)]], the [[Nature Conservancy]], and national governments offer guidance. For instance, the WWF classification system groups ecosystems into [[Ecodistricts]], which are *landscapes characterized by distinct relief, geology, vegetation, and fauna*. These ecodistricts are further organized into ecoregions and ecozones, culminating in continental-sized units called Realms. For example, ecosystems in the *Toronto area fall within ecodistrict 563*, grouped under [[Ecoregion]] 135, the Lake Erie Lowlands, in the [[Ecozone]] Mixed Wood Plains, of the Nearctic Realm. The [[National Ecological Framework]] for Canada provides maps showcasing ecodistricts, ecoregions, and ecozones across the country, facilitating a better understanding of the spatial distribution of ecosystems. **Key Points:** - Understanding ecosystems involves determining the relevant scale based on the phenomena of interest. - Challenges include uncertainties and difficulty in defining boundaries. - The WWF classification system groups ecosystems into ecodistricts, ecoregions, ecozones, and Realms. - Example: Toronto area ecosystems fall within ecodistrict 563, ecoregion 135 (Lake Erie Lowlands), in the Mixed Wood Plains ecozone of the Nearctic Realm. - The National Ecological Framework for Canada provides maps showcasing ecosystems across different scales. ## Biotic and Abiotic Elements of Ecosystems Ecosystems comprise a *dynamic interplay between biotic (living) and abiotic (non-living) components*. In terrestrial ecosystems, the biotic aspect encompasses *plants, animals (including soil-dwelling species), fungi, bacteria, and viruses*. The interaction among these organisms shapes the ecosystem's functioning. Meanwhile, the abiotic component includes the physical environment such as *landform, soil, water table, climate, and air composition*. Both biotic and abiotic components are dynamic processes influencing each other and connecting ecosystems across landscapes. For instance, regional [[Evapotranspiration]] from tropical rainforests interacts with [[Air Circulation Patterns]] to produce local daily downpours. Soil formation, a crucial abiotic element, results from centuries of interactions among mineral components, water, plant roots, soil fauna, fungi, and bacteria. *Soil connects to larger-scale ecosystem phenomena like water flows, atmospheric humidity, air circulation patterns, and nutrient cycles* involving water and atmospheric elements like nitrogen and sulfur. Biotic elements interact in various ways, influencing the abiotic component. Ecosystem plant communities, besides affecting soil development and air circulation, also impact heat dissipation. They do so by having *complex spatial structures that effectively cool local temperatures*, thus maintaining suitable conditions for plant biochemical processes. **Key Points:** - Ecosystems involve dynamic interactions between biotic and abiotic components. - In terrestrial ecosystems, biotic components include plants, animals, fungi, bacteria, and viruses, while abiotic components consist of physical elements like soil, water, and climate. - Interactions between regional evapotranspiration and air circulation patterns can lead to localized downpours. - Soil formation is a result of long-term interactions among various factors, connecting to larger-scale ecosystem phenomena. - Biotic elements, particularly plant communities, influence the abiotic component by affecting soil development, air circulation, and heat dissipation. - Plant communities' spatial structures play a role in cooling local temperatures, maintaining suitable conditions for biochemical processes. ## Energy Dissipation by Ecosystems [[Photosynthesis]] is a vital biochemical process through which plants utilize sunlight to convert carbon dioxide and water into glucose and oxygen. This process involves two major sets of reactions: the *light reactions driven by specific wavelengths of light,* and the [[Calvin Cycle]], which fixes carbon dioxide into glucose. However, photosynthesis is not 100% efficient due to the second law of thermodynamics, resulting in the dissipation of some energy as heat. [[Cellular Respiration]], on the other hand, involves the conversion of glucose and oxygen into carbon dioxide, water, and energy in the form of ATP molecules. *Similar to photosynthesis, cellular respiration also leads to the dissipation of some energy as heat*. These two processes, photosynthesis and cellular respiration, are crucial for the functioning of ecosystems, as they provide energy for various biochemical reactions and the maintenance of life. [[Evapotranspiration]] is a process through which plants dissipate heat and maintain their temperature equilibrium. Plants absorb sunlight, but not all of it is used for photosynthesis; some is absorbed and reradiated as heat. To prevent damage to their tissues, plants utilize evapotranspiration, which involves the *absorption of water from the soil, its movement to leaves, and subsequent evaporation from leaf surfaces*. This process helps in *dissipating short-wavelength infrared heat into longer-wavelength heat*, effectively cooling the plant and its surroundings. **Key Points:** - Photosynthesis converts carbon dioxide and water into glucose and oxygen using sunlight. - Cellular respiration transforms glucose and oxygen into carbon dioxide, water, and ATP energy. - Both processes involve the dissipation of some energy as heat due to the second law of thermodynamics. - Evapotranspiration is a cooling mechanism in plants, where water absorption and evaporation help dissipate heat, maintaining plant temperature. - Evapotranspiration plays a crucial role in ecosystem cooling, water cycle regulation, and local climate patterns. ## Trophic Levels (Food Webs) and Energy Dissipation (see [[Trophic Levels]]) The complexity of ecosystems is rooted in the interactions among living organisms, with energy from photosynthesis driving these interactions. Plants, as primary producers, convert sunlight into glucose, termed Gross Primary Productivity (GPP), which sustains life within ecosystems. However, only a portion of GPP, termed [[Net Primary Productivity (NPP)]], is available to support higher trophic levels due to energy loss through respiration and waste. Trophic levels, depicted in pyramids, *illustrate the flow of energy through an ecosystem*, with each level containing less biomass. Primary consumers, or [[Herbivores]], consume plant biomass, followed by secondary consumers ([[Carnivores]]) and potentially higher trophic levels, with each level having less biomass. Waste and dead organisms from each trophic level are decomposed by [[Saprotrophs]], completing the cycle. Food chains and webs map out these feeding relationships, showcasing the intricate connections within ecosystems. Food webs vary in complexity, from straightforward in early succession to highly complex in climax communities. Feeding relationships extend beyond traditional herbivory and carnivory to include [[Parasitism]], [[Symbiosis]], [[Mutualism]], and [[Commensalism]]. Parasitism involves one organism benefiting at the expense of another, whereas symbiosis, including mutualism, involves mutual benefits. Commensalism entails one species benefiting from the other without harming it. These relationships contribute to the overall stability and resilience of ecosystems. **Key Points:** - Ecosystem complexity arises from interactions among living organisms fueled by photosynthesis. - Trophic pyramids illustrate the decreasing biomass at each trophic level. - Food chains and webs depict feeding relationships within ecosystems, ranging from simple to highly complex. - Feeding relationships extend beyond herbivory and carnivory to include parasitism, symbiosis, mutualism, and commensalism. - These relationships contribute to ecosystem stability and resilience. ## Population Stability (see [[Population Stability]]) The *ecological unit of significance within any species is the population*, which must have the capacity to reproduce healthy offspring adapted to its habitat for persistent presence in ecosystems. Reproduction necessitates more than two genetically unique individuals, with the minimum number required varying among species based on their reproductive behavior. *A minimum population size is crucial for species to endure indefinitely, encompassing reproductive, juvenile, and older, non-reproductive individuals*. Insects often exhibit temporal segregation of life stages, while spatial segregation is observed in other organisms like plants, influencing their reproductive capabilities. **Key Points:** - Population, not individual presence, is ecologically significant. - Reproduction requires genetic diversity and a minimum number of individuals. - Minimum population size varies based on species and reproductive behavior. - Population stability depends on age and genetic diversity. - Insects may exhibit temporal segregation of life stages. - Spatial segregation affects reproductive capabilities in plants. - Persistent populations require a characteristic level of diversity. Additionally, understanding a species' life cycle and habitat needs for all life phases is vital for restoration efforts. For instance, the Black Swallowtail Butterfly undergoes distinct life stages, each with specific habitat requirements. From egg-laying to adulthood, *the species' lifecycle involves multiple molting stages and habitat changes*. Adult butterflies, especially males, engage in behaviors like puddling to obtain essential minerals for mating and reproductive success. ## Community Spatial Structure and Species Composition (see [[Spatial Structure]]) The biotic component of an ecosystem encompasses all individuals within their respective species populations, forming the ecological community through their interactions. *The spatial distribution of individuals and species populations defines the community's spatial structure*. The complexity of this structure depends on species diversity, with greater diversity typically leading to more intricate spatial arrangements. However, there's a point where both spatial structure complexity and species richness stabilize over time, indicating a relatively stable community composition. Abiotic factors significantly influence ecosystem dynamics. [[Insolation Patterns]] and [[Soil Moisture]] availability are major influencers, with *intense sunlight and consistent soil moisture correlating with higher species diversity*. Globally, moist [[Tropical Rainforests]] harbor the most diverse communities, while high-latitude deserts exhibit lower species richness. Topographical variations also play a crucial role, with *mountainous regions generally hosting higher species richness due to diverse microclimates and habitats*. Additionally, soil characteristics and seasonal temperature patterns contribute to shaping community diversity. [[Insolation Maps]] reveal intense sunlight in tropical desert areas and high altitudes, while [[Soil Moisture Capacity Maps]] show a correlation between low moisture soils and high insolation areas, such as deserts. Conversely, high moisture capacity soils coincide with tropical regions and mountainous areas influenced by moist oceanic air-flow. [[Global Plant Species Diversity Maps]] demonstrate a concentration of biodiversity in the tropics, especially in mountainous regions, while lower diversity is observed at higher latitudes and in desert areas. This pattern underscores the combined influence of insolation, soil moisture, and [[Topography]] on biodiversity distribution. **Key Points:** - The biotic component of ecosystems comprises individuals within species populations, forming ecological communities with diverse spatial structures. - Species diversity influences spatial complexity, with higher diversity generally leading to more intricate community structures. - Abiotic factors like insolation patterns, soil moisture availability, topography, and soil characteristics significantly impact species diversity and community composition. - Intense sunlight and consistent soil moisture correlate with higher species diversity, with moist tropical rainforests harboring the most diverse communities. - Mountainous regions exhibit higher species richness due to diverse habitats and microclimates. ## Ecosystem Changes During Succession (see [[Ecological Successions]]) The section discusses the dynamic nature of ecosystems, emphasizing how *spatial structure and species composition constantly change* due to various factors such as births, deaths, migrations, and shifts in the abiotic environment. Under normal circumstances, these changes fluctuate around an average state. However, catastrophic disturbances initiate [[Secondary Succession]], leading to the development of seral communities until a climax community is established once again. Throughout this process, *spatial structure becomes more intricate, and species diversity increases, accompanied by significant alterations in ecosystem complexity and richness*. Early successional stages are characterized by simpler structures and compositions, gradually evolving into more resilient communities with greater species interactions and environmental complexity. A comparison between early and late successional communities highlights the *increase in vertical partitioning of light in later stages*, providing diverse opportunities for species with different light preferences, including seasonal guilds exploiting variations in light availability. **Key Points:** - Ecosystems undergo constant changes in spatial structure and species composition due to various factors. - Catastrophic disturbances initiate secondary succession, leading to the development of seral communities until a climax community is re-established. - Spatial structure becomes more complex, and species diversity increases throughout succession. - Early successional stages are simpler and less resilient, while later stages exhibit greater resilience due to increased species interactions and environmental complexity. - Late successional communities feature increased vertical partitioning of light, offering diverse opportunities for species with different light preferences, including seasonal guilds. ## Influences Affecting Successional Trajectory and Ecosystem Resilience There are intricate processes of ecological succession influence community structure and species composition along successional trajectories. It emphasizes the significance of local influences, particularly the nature of the [[Soil Seed Bank]], in shaping the progression of ecosystems towards climax communities. *Seeds of early seral plants, with long viability periods, require specific conditions like sunlight and fire for germination*, while later seral and climax community seeds often rely on fungal interactions and shade. The richness of the seed bank influences ecosystem resilience post-catastrophic disturbance, essential for recovery. **Key Points:** - Community structure and species composition along successional trajectories are influenced by various factors, including the nature of the soil seed bank. - Seeds of early seral plants have long viability periods and require specific conditions like sunlight and fire for germination. - Later seral and climax community seeds often rely on fungal interactions and shade for germination. - The richness of the seed bank influences ecosystem resilience post-catastrophic disturbance. - Ecotone species play a crucial role in accelerating species movement between ecosystems during recovery from disturbance. - Successional trajectories and ecosystem resilience are affected by the frequency and intensity of catastrophic disturbances. - Human activities such as fire suppression, land use for crop production, and industrial agricultural practices impact the soil seed bank and slow down successional trajectories. - Human-built environments render ecosystems less resilient to catastrophic disturbance, affecting landscape sustainability.