up:: [[CKLA400 - Ecology and Sustainable Landscapes]] x:: [[Ecology and Landscape Ecology]] tags:: #source/course #on/design #on/landscape_design # CKLA400 M2 - Principles of Landscape Ecology 1 The module introduces essential concepts and principles of [[Ecology and Landscape Ecology]], focusing on their implications for landscape sustainability and management. Ecology involves studying *inter-relationships between organisms and between organisms and their biotic and abiotic environment*. These relationships are complex and dynamic, contributing to ecosystem structure and processes. [[Ecosystems]], though unique, can be categorized based on factors like climate and soil, forming identifiable types such as wet meadows or deciduous forests. At the landscape scale, multiple ecosystems may be present, with their structures and dynamics interconnected. Landscape [[Ecological Scales]] include regional, watershed, agricultural, rural, suburban, and urban, with each scale encompassing various ecosystems. The choice of scale depends on the issue at hand, emphasizing the importance of matching issues with appropriate landscape ecological scales. *Understanding human impacts requires identifying the relevant landscape ecosystem scale.* Human behavior significantly influences ecosystems and landscapes, ranging from direct to indirect impacts, from individual to institutional actions, and from local to global effects. ## Ecological Structure, Process and Dynamics (see [[Ecological Structure]]) The structure of an ecosystem encompasses several aspects, including its physical layout, [[Species Composition]], distribution and size of populations, age distribution within populations, and genetic variation. Researchers focus on relevant aspects, such as the density and size of populations, when studying issues like rare plant species within an ecosystem. Understanding *factors like age distribution and genetic variation can offer insights into the viability of species* within an ecosystem. The spatial structure of an ecosystem refers to its 3-dimensional physical organization, which can vary greatly depending on the ecosystem type. *For instance, a climax hardwood forest exemplifies a specific spatial structure, while a meadow ecosystem showcases species structure when plants are in bloom*. Additionally, species within ecosystems exist as populations, with their presence evident in habitats like alpine meadows, where the Lupine population can be observed through its violet flowers. [[Ecosystem Processes]] involve the intricate [[#Flows and Cycles]] of energy and material through both living and non-living components. These processes range from water evapotranspiration to photosynthesis to nutrient uptake and release, encompassing various feeding relationships among organisms. [[Ecosystem Dynamics]] refer to the continuous changes in structure and processes over time, which can vary among ecosystems. These changes may be influenced by *disturbances or perturbations, leading to shifts in spatial structure, species composition, and processes*. Succession is a key concept in ecosystem dynamics, describing the sequential change in vegetation and associated animals, either due to environmental changes or intrinsic organism properties. [[#Primary and Secondary Succession]] outline the progression of vegetation communities in response to changes, culminating in a climax equilibrium state. ## Flows and Cycles Ecosystem processes can broadly be classified into [[Flows and Cycles]]. Flows involve energy transformations, while cycles encompass the movement of materials within and between living organisms and the abiotic components of the ecosystem. Energy flows primarily through processes like [[Photosynthesis]], [[Evapotranspiration]], and [[Air Circulation Patterns]]. Photosynthesis converts sunlight into biochemical energy, sustaining life forms through gross primary production (GPP) and net primary production (NPP), which forms the basis of feeding relationships in ecosystems. Evapotranspiration, largely mediated by plants, dissipates heat from ecosystems. Air circulation, a complex interplay of heat exchange and kinetic energy, also affects ecosystems significantly, contributing to climate patterns and seasonality. **Key Points:** - Flows and cycles are two fundamental processes in ecosystems, with flows involving energy transformations and cycles encompassing material movements. - Major energy flows include photosynthesis, evapotranspiration, and air circulation, which drive ecological processes and influence climate patterns. - Photosynthesis converts sunlight into biochemical energy, sustaining life forms through GPP and NPP, which form the foundation of feeding relationships in ecosystems. - Evapotranspiration, facilitated by plants, dissipates heat from ecosystems, particularly in water-abundant environments like rainforests. - Air circulation, driven by complex factors like heat exchange and kinetic energy, affects ecosystems significantly, contributing to climate patterns and seasonality. - [[Nutrient Cycles]], including carbon, oxygen, and various minerals, are driven by energy and involve absorption, transfer, and release of nutrients within ecosystems. ## Primary and Secondary Succession (see [[Ecological Successions]]) Succession, whether primary or secondary, encompasses the *sequential change in vegetation and associated animals resulting from environmental shifts or intrinsic organism properties*. While primary succession occurs on bare areas devoid of previous community remnants, secondary succession arises from disruptions to existing communities due to major environmental disturbances. [[Gap-phase Succession]], a specialized type, is particularly relevant to discussions of sustainable landscapes in urban environments. The term "community change" is sometimes used instead of succession to highlight its open-ended and variable nature. In both primary and secondary succession, communities transition through distinct stages termed [[Seres]] until reaching a relatively stable climax community. Factors influencing succession include interactions between organisms and the physical environment, with outcomes well-documented across various ecosystem types. While the specific seral sequence varies, broadly definable types of secondary succession exist, with *characteristic seres leading to a climax community similar to pre-disturbance conditions*. The intensity and duration of disturbances can alter succession outcomes. [[Old-Field Succession]], triggered by agriculture abandonment, and post-fire succession in temperate forests are well-studied examples. In old-field succession, annual and biennial herbaceous plants initially dominate, giving way to longer-lived herbaceous perennials, shrubs, and eventually shade-tolerant trees in a multi-stage process spanning decades. [[Post-Fire Succession]] involves nutrient-rich ash and diverse seed banks jump-starting the initial sere, leading to a quicker transition to climax communities resembling pre-fire conditions. Various factors, including [[Seed Banks]], soil nutrients, land-use history, and environmental conditions, influence the composition and duration of each sere. Successional *trajectories generally trend towards increasing ecosystem complexity*, with changes occurring across multiple ecosystem variables. Further exploration of these variables is covered in subsequent modules. **Key Points:** - Succession involves sequential changes in vegetation and animals due to environmental shifts or intrinsic organism properties. - Primary succession occurs on bare areas, while secondary succession arises from disruptions to existing communities. - Seres transition through stages until reaching a relatively stable climax community. - Old-field and post-fire successions are well-studied examples, influenced by factors such as seed banks, soil nutrients, and environmental conditions. - Successional trajectories generally lead towards increased ecosystem complexity. ## Ecotones (see [[Use Edges and Value the Marginal]]) [[Ecotones]], defined as the *transitional zones between different ecosystems or biological communities*, exhibit a distinct spatial and species structure, known as the edge effect. These areas contain species characteristic of both adjacent communities as well as *unique species found only in ecotones*. Ecotones are rich in species diversity compared to the neighboring communities, showcasing a mix of flora and fauna from both sides. *They form spontaneously, often after disturbances like secondary succession events, where destroyed vegetation borders undisturbed surroundings*. Over time, ecotones expand into the disturbed area, facilitating the spread of specific plants through seed transport by animals preferring ecotones. Ecotones manifest in various contexts, including between wetland and forest ecosystems, where they develop more slowly as wetland areas shrink from organic matter accumulation while forests advance. These ecotones host unique plant species adapted to wet or acidic conditions, such as Alder, Willows, and Red Maple. In human-disturbed landscapes like agricultural areas, ecotones arise due to frequent disturbances like plowing or mowing. These ecotones tend to have abrupt transitions and accumulate more unique ecotone species, leading to spatially static boundaries. *Fragmentation caused by human activities can result in extensive ecotones* with implications for climax community development. **Key Points:** - Ecotones are transitional zones between ecosystems with distinct spatial and species structures. - They form spontaneously, often after disturbances like secondary succession events. - Ecotones facilitate the spread of specific plant species through seed transport by animals. - Human-disturbed landscapes like agricultural areas also host ecotones with abrupt transitions and unique species compositions. ## Patch, Matrix, Corridor, and Network (see [[Landscape Patterns]]) Landscape ecology focuses on understanding the patterns of size, configuration, and orientation of ecosystems at the landscape scale, encompassing the physical structure and dynamics across ecosystems. It categorizes landscapes into [[Patch, Matrix, Corridor, and Network]], which constitute different components of the landscape structure. A patch refers to a distinct area of vegetation surrounded by a contrasting context, with boundaries or edges delineating its isolation within the landscape. These patches vary in scale, shape, and may change over time. The context surrounding patches is termed the matrix, which represents the prevalent vegetation type across the landscape. Corridors are *linear elements connecting patches* within the landscape, facilitating movement for organisms between patches. They can be natural features like streams or man-made structures like roads, often serving as pathways for reproductive linkage among fragmented populations. However, corridors may also act as barriers to certain organisms, particularly in highly fragmented landscapes. *Networks emerge when patches and corridors are well-connected*, forming intricate patterns across the landscape. These networks can be fine-grained or coarse-grained, depending on the size and dispersion of patches and corridors. **Key points:** - Landscape ecology studies patterns of ecosystems at the landscape scale, focusing on structure, processes, and dynamics. - Patches vary in scale, shape, and change over time, surrounded by contrasting contexts. - Corridors facilitate movement between patches, aiding reproductive linkage but can also act as barriers. - Networks form when patches and corridors are well-connected, categorized as fine-grained or coarse-grained based on patch size and dispersion. ## Process and Dynamics Across Landscape Ecosystems (see [[Ecosystem Processes]]) The interconnectedness of individual ecosystems extends across landscapes, influenced by processes such as *sunlight variation, air movement, and topographical features*. Differential heat reflectance from plant communities leads to air movement, connecting warmer and cooler areas. These airflows, along with larger scale atmospheric circulations, facilitate the transfer of water, gases, nutrients, and biomass across ecosystems. Liquid water flow within ecosystems transports various materials into larger water bodies, stitching ecosystems together. Seasonal fluctuations strongly affect these flows, including migratory patterns of birds and mammals. - Sunlight variance across plant communities leads to differential heat reflectance, causing lateral air movement. - Airflows facilitate the transfer of water, gases, nutrients, and biomass across ecosystems. - Liquid water flow transports materials into larger water bodies, connecting ecosystems. - Seasonal fluctuations strongly influence these flows, including migratory patterns. [[Disturbance]] forces like fire, flooding, and windstorms influence plant community dynamics, tightly linking succession processes across landscapes. Regional disturbances, such as forest fires and floods, affect surrounding ecosystems by altering successional pathways and distributing seeds and organisms. ## Scale Issues The concept of scale in ecosystems and landscape ecology is crucial, as it influences both spatial and temporal dimensions of these systems. Ecosystems vary in size and duration, ranging from ephemeral ponds lasting several months to mature forests persisting for centuries. Generally, *larger ecosystems tend to endure longer, although disturbances can alter this correlation*. Understanding ecosystem scale involves recognizing coherent patterns in structure, processes, and dynamics. In landscape ecology, scale issues become more complex. [[Landscape Patterns]] of patches, corridors, and networks are observable at specific spatial scales but may disappear at smaller or larger scales. The scale of observation depends on the observer's goals and may vary for different organisms. For instance, *accommodating the perceptual scale of organisms like insects or birds differs from human perception*. Considering an organism's perceptual scale aids in discerning patterns affecting it across landscape ecosystems. Another crucial aspect of scale *involves the interplay between patterns at different spatial and temporal scales*. This multi-scalar phenomenon is central to landscape ecology. For example, annual spring flooding in watersheds like the Red River showcases how structures, processes, and dynamics at various scales interact. Snowmelt in the river's upper reaches intensifies flood pulses downstream, affecting vast areas until reaching the delta. This feedback between scales is essential for sustainable landscape management. **Key Points:** - Ecosystems vary in size and duration, with larger ecosystems generally lasting longer. - Landscape ecology considers patterns of structure, processes, and dynamics at specific spatial scales, influenced by the observer's goals and organisms' perceptual scales. - Interactions between different spatial and temporal scales are crucial in landscape ecology, exemplified by phenomena like annual flooding in watersheds. ## Human Influences [[Human Influences on Ecosystems]], spanning a wide range in terms of their intensity, duration, and scope, are significant factors in landscape dynamics. To develop and manage sustainable landscapes, it's crucial to comprehend these influences. Various factors contribute to these influences, such as *resource extraction, manufacturing activities, pollution, recreational pursuits, legal frameworks, cultural biases, and agricultural practices*. These influences can be classified based on several criteria including individual versus group actions, formalized versus ad hoc activities, and direct versus indirect impacts. Often, multiple influences interact simultaneously, periodically, or sporadically within ecosystems, affecting their ability to persist in robust conditions. Some human activities, like resource extraction and manufacturing, can have profound and lasting impacts on ecosystems. For instance, clear-cut logging alters forested landscapes significantly, while structures like the Hoover Dam can completely transform river ecosystems. Additionally, the use of fossil fuels and hydroelectricity leads to consequences like light pollution, as depicted in global maps. On the other hand, *individual actions, such as gardening and animal husbandry, can sometimes enhance ecosystems*. However, recreational activities like ATV use or camping may cause considerable disturbance to natural habitats. The challenges posed by human influences on landscape ecosystems are multifaceted. These influences affect the sustainability and resilience of ecosystems, which are crucial for maintaining ecological balance. Assessing and correlating human influences and ecosystem robustness are central to addressing sustainability concerns. **Key Points:** - Human influences on ecosystems vary in range, intensity, and duration, affecting landscape dynamics significantly. - Various activities, including resource extraction, manufacturing, pollution, recreational pursuits, and agricultural practices, contribute to these influences. - Activities like clear-cut logging, dam construction, and sewage treatment have substantial impacts on landscape ecosystems. - Individual actions such as gardening and animal husbandry may sometimes have positive effects, while recreational activities like ATV use and camping can disturb natural habitats.