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Competition and predation in ecosystems
Understanding ecological niche
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For a species to survive and flourish within a given environment, it not only needs to replace itself but also all the other species around it exclusively. Hence, if one species completely replaces another species, the result is a single dominant species, a monoculture (source 2). According to Gause’s law, every species in a given environment occupies different niches for survival. Therefore, two separate species competing for similar resources cannot fundamentally coexist (source Gause). This is known as the competitive exclusion principle. When comparing animal niche’s to that of different autotrophic plants, one can rather easily differentiate adequate ecological niches for the animal species merely based on food-requirements (P.J. Grubb). On the contrary, many autotrophic plants contradict the competitive exclusion principle by sharing similar ecological niches such as sunlight, carbon dioxide, water, and alike mineral nutrients (p.j. grubb).
Many old-growth forests across the landscape of northern Lower Peninsula of Michigan contain a mixture of tree species rather than a monoculture. Many researchers have put forward ideas to explain the competition and co-existence of tree species in such communities. A theory explaining competition and co-existence between two species is gap regeneration. Gap regeneration is when a gap is created upon death of a plant individual and a new individual, sometimes of the same species as died and sometimes not dependent on environmental heterogeneity, takes its place (Kenneth Lertzman). Canopy gaps during gap regeneration can be explained by either reciprocal replacement or habitat preference . In a reciprocal replacement, seedlings of one species would be found predominately under large trees ...
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...le would be more than that of American beech because sugar maple produce more seeds than American beech. Furthermore, we study whether the two species co-exist via reciprocal replacement, habitat preference or merely by chance. We believe that habitat preference may be the mechanism of coexistence here and therefore we hypothesize that there will be more American beech tree neighbors as they may represent the most biomass as per our third hypothesis. Thereafter, root sprouting is effective in American beech to give them a greater horizontal growth than sugar maple. Hence, we hypothesize that sugar maple canopies will be less asymmetrical than American beech. Finally, because a nearby canopy may restrict a tree canopy growth in the same direction, we hypothesize that a tree will grow its respective canopy away from its neighboring canopy to receive maximum sunlight.
Shortleaf pine tends to grow rather slowly in the early stages of its life when compared to its closest competitor, loblolly pine. Therefore it cannot compete for the best sites under natural regeneration, but, because of it's tolerance of a wide range of site conditions, shortleaf pine is found naturally in areas where loblolly pine will not grow effectively. It is for this reason that shortleaf pine was chosen for this site instead of loblolly. When planted artificially, it was found that after the first few years of development, shortleaf pine will match loblolly in height growth on the better sites and will surpass loblolly on the poorer sites (Harrington, 1987). Because of this, shortleaf pine is the most commonly regenerated pine in the northern and western parts of its range where the site conditions are not as ideal as in the southern part of its range.
Reproduction and passing on genetic and behavioral traits to an offspring is a common fundamental to all the species on this planet. When studying forest ecology, it is crucial to study the proportion of individuals surviving at each stage of their growth as the lives and mortality experienced in a species population describes a characteristic of the species in question. In the case of American beech and sugar maple, their attempt to produce seeds is analogous to entering lottery, where every seedling has a potential chance of becoming a canopy but only some will survive and reach the canopy size; thus, becoming the fit ‘winners’. Our information shows that together, based on size class distribution, both the species display a ‘winner takes all’ pattern, which supports our hypothesis. The results showed a greater count for seedlings and short saplings than for tall saplings, sub-canopies and canopies. This is evident for a Type III survivorship curve. In Type III curve all individuals initially having a very low chance of survival. However, once the individuals pass their threshold age and survive, they live an advanced age. Only some individuals out the mast seeding production mature to become fully fit canopy trees. On the other hand, our hypothesis of canopy trees representing the bulk of the biomass was supported as the basal areas decreased going from growth stages of canopy to seedlings. This is evidence that once the individuals survive the bottleneck where there is high mortality of young individuals (seedlings), who are then considered as ‘losers’, will allow for the other larger size class individuals to flourish. Here, having considerable amount of dbh (diameter at breast height) accounts for greater surfac...
These are very difficult questions for me personally to answer because I live in the Pacific Northwest, and I have seen the beauty of the old growth forests first-hand.
Purpose: The purpose of this lab is to investigate the various components of different ecosystems in a smaller representation and study the conditions required for the ecosystem’s sustainability as well as the connections between
Competition between individuals is essential, and is one of the driving forces behind evolution. However, competition has different effects depending on the circumstances. Of course, competition between plants is different than between animals (Miller 1995), and interspecific competition has different effects than intraspecific competition. Plants compere by trying to gather as many resources as possible, as they cannot get up and go somewhere more plentiful. Some expand their root systems to collect more water and nutrients, and other grow taller to collect more sunlight. Either way, increasing competition will lower fitness and variation (Jones 2016) due to the plants having to share the same resources. In this experiment, we are using a protocol based around one developed by Miller and Schemske (1990) to determine the effects of intraspecific competition in Brassica rapa.
Typically people think that redwood forests are made up entirely of redwoods. But that isn't so--a healthy old-growth redwood forest is a mix of redwoods, deciduous trees, ferns, vines, flowers and wildlife. Giant redwoods are so tall, dense, and so crowded in the canopy, that some ground areas rarely see the sunlight, and little grows beneath these large giants. But whenever a tree does fall by Mother Nature or man, it leaves a gaping hole, that goes noticed.
A different scenario takes place when an alien species is transported to a new area. Although direct competition with similar species is still a problem, the new kid in the block may have no natural pests and diseases. Thus, large stands of monocultures can occur. It is generally accepted that one plant species will support 10 species of animals. If one species takes over 99% of a given habitat dozens if not hundreds of species are lost from that area and some populations are stressed enough that extinction is possible.
Landscape fragmentation can be characterized as a break up of a continuous landscape into more smaller, less-connected patches by roads, clearing for agriculture, commercial and residential development, and timber harvesting. Clear-cutting can break up mature, contiguous forest until the clear-cut area has regenerated to a point that it does not act as an ecological barrier to interior species or species that rely on continuous, mature forests. Much of the work that has sought to measure landscape pattern and habitat fragmentation comes out of the disciplines of conservation biology and landscape ecology (Theobald 1998). These disciplines are founded on the premise that landscape patterns strongly influence and are influenced by ecological processes (Forman and Godron 1986).
Through millions of years of evolution, well-balanced habitats have co-evolved to provide for the wide variety of species and their needs. Trees have adapted to weeds, weeds have adapted to the predation from herbivores, and so on up the food chain. Similar scenarios are seen throughout the world. Through the process of natural selection, specific species or broad species families will go extinct. However, these occurrences have largely been due to the natural flow and evolution of time. It wasn’t until recently that dominant species, such as humans, have taken the course of nature into their own hands.
The Western forests are drastically different from what they were like before the European settlement. In pre-European time, the forests were open and park-like with only 25-35 trees per acre surrounded by areas of open grasslands. One could easily ride a horse through the spacious forest. This, however, is not possible in today's forests. Today, for example the Ponderosa pine forests, have over 500 trees per acre, creating thick dense areas of trees, brush, and bushes (President Bush, 4). The pre-European forests were subject to frequent low inte...
Franklin, J. F., et al. (1981). In Ecological Characteristics of Old-Grow Douglas Fir Forest, (GTR PNW-118). Retrieved July 9, 2005, from USDA Forest Service Web Site: http://
We proposed that at what rate (Early, Middle, Late) do the leaves fall on East Carolina’s Campus for the White Oak Tree? Does the rate change in the regions of California and New York? The White Oak has a broad tolerance for thermal and moisture conditions. Depending on the climate is what factors the rate of the leaves falling.
It also has many woody shrubs such as Corylus avellana (Hazel), Euonymus europaeus (Spindle) and Ilex aquifolium (Holly). All these species are dependent on the amount of sunlight that they obtain. Woodlands mainly consists of a Canopy Layer: large trees greater than 5m in height, an Understory Layer: younger species of the dominant trees, Shrub Layer: small, woody plants, Herb Layer: flowering plants, fungi and grasses and the Moss Layer: variety of mosses and
...Buschmann, H., 2007. Nitrogen Enrichment and Plant Invasions: the Importance of Nitrogen-Fixing Plants and Anthropogenic Eutrophication. In Biological Invasions. pp. 163-180.
Various plant and animal species depend on each other for what each offers and these diverse species ensures natural sustainability for all life forms. A healthy and solid biodiversity can recover itself from a variety of disasters. It is estimated that the current species extinction rate is between 1,000 and 10,000 times higher than it would naturally be. Therefore, there is an urgent need, not only to manage and conserve the biotic wealth, but also restore the degraded ecosystems. c) Captivity breeding species can again be reintroduced into the wild.