The final Mishna in Massekhet Shekalim returns to the rules of the shekalim, and specifically to their status in contemporary times when the Mikdash is no longer standing. Incidentally it also touches on some other halakhot that are dependant on the holiness of the Land of Israel and how they are to be kept in the absence of the Temple.
Since the purpose of the shekalim is to pay for communal sacrifices, there really is no reason to continue contributing them as long as the Temple is in a state of destruction. The Mishna rules that shekalim and bikkurim (first fruits) are no longer brought. Nevertheless, if someone sets them aside for those purposes, they become kodesh (consecrated). Since they cannot be used for their designated purpose, the bikkurim must be left to rot and the shekalim should be destroyed. Rabbi Shimon rules that bikkurim cannot be made in our day and age, since they cannot possibly be brought to the Mikdash as is required by the Torah (see 26:2).
The Mishna teaches about a number of other halakhot that apply whether or not the Temple is standing. Ma’aser dagan and ma’aser behema (tithes of grains and animals) as well as the rules of bekhor (first born) apply today even without the Mikdash.
Ma’aser dagan are the tithes that are separated from grains and given to the kohen and the levi.
Ma’aser behema is the obligation to set aside one of every ten newly born animals (see 27:32).
Bekhor is the rule obligating that the first-born animal be given to the kohen (see 13:1-13 and 18:15-18).
While the obligation of bekhor stems from the fact that there is inherent holiness to the firstborn animal, ma’aser behema derives from its connection and similarity to ma’aser dagan. The Bartenura explains that the rules of ma’aser dagan still apply because the holiness attained by the Land of Israel during the second Temple period remains, even when the Temple is no longer standing.