Methods to establish new plant populations are different from establishing vertebrate or animal populations. Animals can move from one place to another in search of food or moisture conditions. In plants the seeds are dispersed to the other sites through wind, water and animals or by conservation biologists activity.
When a seed is planted on a site it is unable to move even if a suitable site exists at few meters distance. The immediate small suitable site is necessary in case when environmental conditions become harsh e.g. the weather is too hot, too wet, too dry or too shady. In these conditions the seeds either don't germinate or plants die. Plants are vulnerable to attacks by insects, pests and fungi. Fire also disturb the seeds establishment.
Considerations while reintroduction of Plants
- Careful site selection should be taken into account otherwise plants will not be able to survive or flower.
- Those factors should be identified that cause the decline in plants species.
- Management techniques should be developed to manage the introduce and native species.
Some plant populations fail to establish when seeds are planted at the sites even sites were found suitable for them. In a case seeds of 6 annual plants species were planted in 48 suitable sites. After 2 years the plant population persisted on 5 sites and after 6 years population persisted on only 1 site. At these successful sites the population size of species of plants increased to 10,000 and it spread to 30 m around margins of marshy pond.
In another case seeds of 35 perennial herbs species were sown at 173 sites. No seedling was observed at 167 sites out of 173 sites. No individuals were seen at 32 out of 35 species.
The problem arise while sowing the seeds is that the species did not mimic the natural process exactly. To overcome these problems new techniques were introduced such as:
- Fencing to exclude animals
- Removal of existing vegetation
- Plant nurse plants in arid regions
- Adding mineral nutrients
Keys to Success
The keys to success are as follows:
- using as many sites as possible
- use as many seeds and adult plants as possible
- reintroducing species year after year at many sites
- careful monitoring of seedlings and adults
Case Study
The large flowered fiddleneck is an annual plant belonging from northern California. It has not a wide range. These species decline due to livestock grazing and fire suppression. Reintroduction of these fiddleneck was done with careful considerations such as management of grass specific herbicides and burning. This was first implemented in experiment than it was applied to natural population resulting in increase in plant population.
