User:PricklyFish/Altitudinal migration

Altitudinal migration is a short-distance animal migration from lower altitudes to higher altitudes and back. Altitudinal migrants change their elevation with the seasons making this form of animal migration seasonal. Altitudinal migration can be most commonly observed in species inhabiting temperate or tropical ecosystems. This behavior is commonly seen among avian species but has also been found in other vertebrates as well as some invertebrates. Altitudinal migration is commonly thought to happen in response to climate and food availability changes as well as increasingly due to anthropogenic influence. These migrations can occur both during reproductive and non-reproductive seasons.

The patterns of altitudinal migration may be affected by climate change resulting in potentially life-threatening situations for some species. Deforestation can affect the migration corridors of altitudinal migrant and could lead to smaller areas for these species to migrate. Changes the environment of altitudinally migrating species can also affect seed dispersal.

Regions
Species that exhibit altitudinal migration can be found in almost every continent on Earth. The only continent in which altitudinal migration cannot be observed is Antarctica. There are many documented examples of migratory range shifts along an elevation gradient among temperate species. While these migrations are more understood in temperate regions, and far less understood among tropical ecosystems and species, there are documented cases. Altitudinal migration is typically seen among taxa found in montane areas. Generally, as elevation increases, the species richness decreases.

** Typical characteristics of tropical altitudinal migrants include: a high rate of frugivory or nectarvory; movement between lower elevation areas during non-breeding seasons and higher elevation areas during breeding seasons, or on a consistent annual or seasonal cycle; at least part of the population being migratory with a possible portion of the population residing at breeding sites year-round. This last characteristic can be sex-biased, as it is with juncos, in which the males are less likely to migrate than the females. The white-ruffed manakin provides a good example of an altitudinal migrant by displaying all of these traits. It has a high rate of frugivory, migrates from lower elevations to higher elevations on a predictable breeding-season based cycle, and part of the population is migratory, with a small portion possibly remaining at the breeding sites year-round. ** (Note: I may remove this paragraph or move it into the section below regarding tropical bird species. If I do move this paragraph down I plan to add more citations within the paragraph as there is only one citation.)

Species
There are many species of animals which exhibit altitudinal migration. While there is many examples of vertebrates which exhibit altitudinal migration, as of 2021 there are few documented examples of invertebrates which exhibit altitudinal migration.

Birds
There are various bird species that perform altitudinal migration. In the tropics, altitudinal migrations are most commonly seen among frugivores or nectarivores, such as what is seen among tropical hummingbirds, which migrate altitudinally in response to shifts in food abundance and availability.

Tropical avian species that are altitudinal migrants include the white-ruffed manakin, resplendent quetzal, at least 16 species of raptor, and many species of hummingbird.

The Hawaiian goose, or Nene, is a species of goose native to the Hawaiian islands which has been known to migrate altitudinally. This species of goose can be found in lower elevations during breeding seasons and when molting, and in higher elevations during non-breeding seasons.

Temperate avian species which have been known to altitudinally migrate include the American robin, mountain chickadee, and American dipper.

Mammals
While less common in avian species in the temperate regions, altitudinal migration still plays a part in migration patterns in montane zones and is seen in most ungulates in the Rocky Mountains. Ungulates that have been observed to migrate altitudinally include roe deer, bighorn sheep, and mountain goats.

There are fewer documented examples of tropical mammal altitudinal migrants. While there are less known examples, some tropical bat species have been known to migrate altitudinally. As of 2014, there is not much information as to why tropical species migrate altitudinally, other than that it may be for food resources or reproduction, as it is for temperate bat species.

Temperate bat species are also altitudinal migrants. Their migratory patterns are sex-biased altitudinal migrations, with females inhabiting lower elevations during reproductive periods.

Invertebrates
There is little documentation regarding invertebrates that migrate altitudinally compared to avian species, but documentation does exist. The Monarch butterfly a species which has been known to migrate altitudinally, as well as the chestnut tiger butterfly. According to Masahito T. Kimura, invertebrates migrate altitudinally "as a means to escape from unfavorable conditions such as low winter temperature, summer heat, low resource availability, high parasitism, severe microbe infection or overcrowding."

Migration corridors
Migration corridors, connecting lowland and montane habitats are essential for the upkeep and survival of migratory species. Some species can cross cleared lands, such as pastures, but many require closed forest areas, such as what is provided by these migration corridors. Deforestation can disrupt these corridors and affect the migration pattern of species which do exhibit altitudinal migration. Deforestation can limit the amount of space available for migration, leading to a more narrow and limited migration pattern.

Causes - Anthropogenic
I plan to expand on this section as well. I plan to add in examples of how humans have disrupted the migration patterns of certain species. I plan to mention deforestation among other topics to expand on this topic. Though this may also work better within the implications section of this article. I will have to continue to write this out to decide where it would best fit. Deforestation can cause altitudinal migrants to seek higher altitudes for food as their previous food source is removed. (Unsure if I will include this)

Other
I plan to fit the citations to make them all a matching format.

Lead
The leading paragraph currently does not seem to flow well and does not discuss all the points to be discussed in article. I plan to edit the leading section to make it more focused around what will be discussed in the article and will state these topics in chronological order. A topic which should be included in the leading paragraph but is not currently mentioned is conservation implications as it is talked about the article but not mentioned in the leading section.

I will also potentially remove or edit the second paragraph in the leading section. This paragraph seems to be more so focused on one example (animals found in tropical zones that display altitudinal migration) and it does not seem like it is a needed paragraph for the leading section. In place of this paragraph I could include a small list of animals which exhibit altitudinal migration and the climates they are found it.

Article body
Within in the Regions and Causes sections I plan to add more references to back up some of the statements made in this article as there are many statements made that have no sources listed to back up the statement. For example, the last sentence in the Tropics subsection within the Regions section or the Nest Predation subsection within the Causes section. These both make statements but do not have cited sources to back up these claims.

Regions

I plan to rework the subcategories, for example the "Tropics" subcategory, to first describe what this climate is and then give examples of animals which can be found in this region which display altitudinal migration. I would also order the animal examples within this region by species or class rather than giving random examples all at once. For example, within the Tropics subcategory I would first state what this climate is and give a broad list of animals which can be found here which exhibit altitudinal migration. I would then list animals in groups based on their species such as listing birds together and then other vertebrates. I also plan to find some examples of invertebrates which display altitudinal migration since the leading paragraph states that some invertebrates do but there are no examples listed within the article.

Causes

I plan to potentially expand on the smaller subsections within this section such as the Anthropogenic subsection. This section is not well explained and I believe more examples of animals which exhibit altitudinal migration for this reason, as well as explaining reasons why some animals may now exhibit altitudinal migration if they did not exhibit this behaviour before.