Columbia subject headings:
Biotic communities--Mexico--Tamaulipas.
Biotic communities--Texas--Lower Rio Grande Valley.
Environmental protection--Mexico--Tamaulipas.
Environmental protection--Texas--Lower Rio Grande Valley.
Nature conservation--Mexico--Tamaulipas.
Nature conservation--Texas--Lower Rio Grande Valley.
Nature--Effect of human beings on--Mexico--Tamaulipas.
Nature--Effect of human beings on--Texas--Lower Rio Grande Valley.
Shrubland ecology--Mexico--Tamaulipas.
Shrubland ecology--Texas--Lower Rio Grande Valley.
Harvard subject headings:
Biotic communities--Mexico--Tamaulipas.
Biotic communities--Texas--Lower Rio Grande Valley.
Environmental protection--Mexico--Tamaulipas.
Environmental protection--Texas--Lower Rio Grande Valley.
Nature conservation--Mexico--Tamaulipas.
Nature conservation--Texas--Lower Rio Grande Valley.
Nature--Effect of human beings on--Mexico--Tamaulipas.
Nature--Effect of human beings on--Rio Grande Valley.
Nature--Effect of human beings on--Texas--Lower Rio Grande Valley.
Shrubland ecology--Mexico--Tamaulipas.
Shrubland ecology--Rio Grande Valley.
Shrubland ecology--Texas--Lower Rio Grande Valley.
Princeton subject headings: