MEGAFAUNA - Large vertebrates, especially the larger mammals.
MESOCOSM - An enclosed and essentially self-sufficient (but not necessarily isolated) experimental environment or ecosystem that is on a larger scale than a laboratory microcosm.
MACROCLIMATE - The general climate of a relatively large area.
MICROCLIMATE - The climate of a small or restricted area, or of the immediate surroundings of an organism or object of interest, esp. where this differs from the climate generally.
MICROCOSM - A small-scale natural ecosystem, regarded as a model of ecological principles.
MONITOR - To collect and analyze data by various methods for the purpose of understanding and documenting changes both favorable and unfavorable to natural ecosystems and features.
MONOCULTURE - The cultivation or exploitation of a single crop, or the maintenance of a single kind of animal, to the exclusion of others.
MORPHOLOGY - Shape, form, external structure or arrangement, esp. as an object of study or classification.
MOSS - A plant of the class Musci (or Bryopsida), comprising small bryophytes with scalelike leaves usually spirally arranged, and with a sporophyte generally opening by a lid, which grow in masses in bogs, on the surface of the ground, on stones, trees, etc.
MUTUALISM - The relationship existing between two organisms of different species which contribute mutually to each other's well-being; an instance of this.