The Implications Of Density Dependence

The Northern Correboree Frog is an endangered species that is restricted to montane, subalpine woodlands, grassland and heathland 1,000 metres above sea level. The estimated amount of Northern Correboree Frogs is 1000-5000. One of the reasons why the Northern Correboree Frog is endangered is because of climate change. Climate change affects the Northern Correboree Frog because it was predicted that its population would decrease in winter and spring precipitation because, this would make one of the popular breeding habitats (edges of bog pools) very saturated and dry, which makes it hard for the frogs to breed.

Horseshoe crabs are an important part of the wetland ecosystem, however they are going extinct. Due to harvesting, pollution, and other animals consuming their offspring their numbers are dwindling. They play an important part in the ecosystem and need to be protected so they do not become extinct. The Delaware bay has decided to protect them for their future uses in medicine and to keep them as an important role in the ecosystem.

Texas Horned Lizards (P. cornutum) are currently listed as a threated species in Texas and Oklahoma. Texas Horned Lizard decline has been documented to start in the 1960’s, and is attributed to many things such as the invasion of red fire ants, habitat loss, urbanization, and the increased use of insecticides (Donaldson, Price, and Morse, 1994). These lizards inhabit arid to semi-arid environments and are known to primarily eat harvester ants. However, other invertebrates have been noted such as spiders, crickets, and beetles (Montanucci, 1989). The Horned Lizards dependence on Harvester ants has already been brought to question when it was shown that habitat influences population distribution and not harvester ant availability (Whiting,

Crayfish, Orconectes propinquus, are ectotherms that do not generate internal heat and rely on external temperatures to determine their body temperature. The crayfish we tested were found in Medway Creek and therefore undergo considerable temperature changes throughout the year. Since these crayfish are able to adapt to various temperatures allowing them to live in numerous places, their survival rate would be higher than many other organisms.

The macroinvertebrates graph (figure 2) represents the diversity of species inhabiting the Baldwin Swamp. In 2009 the Baldwin swamp was flourishing with a large diversity of species. A total of 33 macroinvertebrates, 8 species were recorded. At this time the baldwin swamp was healthy, abundant in life and the ecosystem and food webs were unaffected by the floods. Whereas 3 weeks after the floods swept through there were little to no range of species of macroinvertebrates. There were a recorded amount of 2 Damselfly Nymph and 1 waterboat man. A theory to why these two

Different aquatic invertebrates live in different micro habitats (smaller habitats) at Lake Tonetta. Some live on the surface of the water. Others live in the bottom of the lake, or deep within the sediments at the bottom of the lake. The water pH is important because they only can live in a specific pH 6.5-7.5.When we visit the lake our group checked the biodiversity (The variety of plants and animal species in an environment)of Lake Tonetta by counting the aquatic invertebrates in a sample obtained using dip nets and bottom scrapers. During our trip, we found beetles, snails, worms ,

Florida has more introduced species of reptiles and amphibians in the wild than anywhere else in the world, causing the native populations to become unbalanced (University of Florida, 2012).

The threatened bog turtle is a very small turtle, averaging 3.1 to 4.5 inches in length (USFWS 2015z) and it is characterized by a light brown to ebony shell and bright yellow, orange, or red blotches on each side of the head (USFWS 2001). The FWS proposed a final rule in 1997 to list the northern population of the bog turtle as threatened and southern population as threatened due to similarity of appearance, under provisions of the Endangered Species Act of 1973 (62 FR 59605 59623, November 4, 1997). Regionally the northern population of the bog turtle is known to occur in localized distributions from western Massachusetts and Connecticut southward to Maryland, and the southern population is known to occur from Virginia southward to Georgia (USFWS 2001). In New York it is known to occur in 15 counties in the southeastern region of the state or along the south coast of Lake Ontario (USFWS

This species habitat is the longleaf pine-wiregrass flatwoods. The adult salamanders eat earthworms, insects, and are likely to eat other invertebrates as well. The larvae eat a variety of aquatic invertebrates, especially crustaceans. The Flatwood Salamander’s population is roughly several thousand, and is decreasing. Part of the community that the salamanders live in consists of decaying logs, vegetation, earthworms, and insects. Part of the ecosystem that they live in consists of decaying logs, vegetation, earthworms, insects, crayfish burrows, forest fires, and shallow ponds.

Unfortunately, freshwater snails like many other river species across North America are threatened. The abundance and variety of snails have dramatically declined over the last 80 years, especially those species that inhabit streams and rivers. Approximately 60 species of freshwater snails are presumed extinct, 20 are on the federal endangered or threatened species list, and another 290 species are of conservation concern nationwide. The decline of freshwater snails began in the early twentieth century. Dam construction and other channel modifications, siltation, and industrial and agricultural pollution have all degraded the river habitats on which most species depend. As a result, the species richness and the abundance of freshwater snails have declined dramatically. This decline has been especially pronounced in the Southeastern United States where these animals are most diverse. The continued loss and decline of freshwater snails and other river species are testament to the fact that despite significant water-quality improvements made in the last 25 years, much work remains if we are to halt species

Known in the scientific community as Bufo marinus, cane toads were introduced to Australia in the mid-1900’s t rate from their native home of South America. Sugarcane crops were at risk of destruction from the infestation of beetles, and these species were brought in to help counter the negative effect that the beetles were having on farms. These amphibians have the ability to grow up to 4.4 pounds, and were soon doing more harm than good. Not only were the cane toads eating the beetles that they were meant to, but they also started including native insect-eaters in their diets (Roach). This new addition to their food source helped the toads to thrive and expand their habitat region.

Sharon A. Poessel, Eric M. Gese, Julie K. Young, (2014). Influence of habitat structure and food

The bullfrog, Lithobates catesbeianus (Shaw 1802), is a common aquaculture species that has become a dangerous invasive species. Considering that this North American anuran involve a great risk to native communities, its invasion is a mayor threat to biodiversity at the Neotropic. The invasion of this species is associated with different continental aquatic systems, but it displays a preference to the permanent ponds and water reservoirs. In Uruguay, three bullfrog populations were detected so far, two of which have failed to establish (a situation that seems to have happened in several cases), but one persisted and is expanding in Aceguá, Cerro Largo. Although local authorities are concerned about this invasion, no control action was implemented

Density is the first section that we learned about urbanism. Density is similar to the same density of science. How much stuff or matter within an amount of space. So we had to design a plan and also a model of what do we feel density is. To the following page I showed you my design of triangles and how they are closed and clustered together with different size and heights.

In addition to the conservation benefits of recognizing that metapopulations have spatial structure, a number of important conservation risks arise when conservationists do not account for the various potential spatial structures of metapopulations. One of the risks of assuming homogenous spatial structure is that the models will produce falsely high numbers, as the actual population violates the assumptions of the model. Wootton and Bell (1992) highlight the importance of addressing spatial structures in their model of Peregrine Falcon populations, as the census data alone would predict a falsely healthy population. Additionally, management plans in populations might be terminated prematurely if conservationists do not understand and account for the dynamics of source and sink metapopulations, which may have fluctuating levels of colonization and extinction rates that are normal for the dynamics of the population (Wootton and Bell 1992). Kauffman et al. (2004) echo this finding, as they emphasize the importance of understanding habitat-specific demographic data instead of an overall population count alone, which might carry the assumption of homogenous spatial structure and lead to a misdiagnosis of a population.