We found that there are representatives of all the major functional ecological groups (predators, scavengers, detritivores, herbivores) among invertebrates in Central Park leaf litter. As might be predicted in such an urban setting, a significant number of the species have a widespread distribution or are introduced species of European or Asian origin.

These exotic species are more prevalent in groups such as centipedes, millipedes, annelid worms, isopods and mites that have a greater propensity to travel with humans, for example, in soil and on plant roots.
A julid millipede.	Top: a lithobid (stone) centipede. Bottom: a geophilomorphid (soil) centipede.	Mesostigmatid mites (Acari).

Most of the ants, beetles, and spiders were identified as native species.
Dysderidae (Dysdera crocata, male spider, introduced from Europe).	Formicidae (worker ant).	Some genera of Staphylinidae (Rove beetles).

In addition, the number of species present in some invertebrate groups is much lower than that found in other non-urban forests such as Black Rock Forest in the metropolitan New York region. This may be due in part to the fact that we only used one sampling technique (Berlese funnel) for this survey. Additional survey methods such as pitfall traps may have uncovered more species. Species diversity is also affected by the challenging environmental conditions of the city. Heavy use by Park visitors compacts the soil and leads to soil dryness. Cities often have higher pollutant levels that can have negative effects on soil and litter communities. The higher air temperatures of cities may also affect the amount of soil moisture available to these animals.

In addition, the intense grazing activity of high densities of non-native earthworms may be significantly reducing the amount of litter available for other species.

Earthworms (Annelida).

A thriving community of litter and soil organisms provides the base for a healthy forest ecosystem, in turn supporting important ecological processes and all the other plants and animals that live there.

General view of raw sample.

With continued restoration work in Central Park, litter and soil conditions should improve, leading to increased litter species diversity. Simple measures such as leaving fallen leaves and branches and whole trees to decompose where they fall, minimizing soil disturbance in Park woodlands by encouraging Park visitors to stay on trails and avoid trampling leaf litter, will go a long way towards achieving these goals.