Forest area and distribution in the Mississippi alluvial valley: implications for breeding bird conservation

Summary Knowing the current forest distribution and patch size characteristics is integral to the development of geographically defined, habitat-based conservation objectives for breeding birds. Towards this end, we classified 2.6 million ha of forest cover within the Mississippi Alluvial Valley using 1992 thematic mapper satellite imagery. Although historically this area, from southern Illinois to southern Louisiana, was dominated by forested wetlands, forest cover remains on less than 25% of the floodplain. Remaining forest cover is comprised of > 38,000 discrete forest patches > 2 ha. Mean patch area (64.1±5.2 ha; x±SE) was highly skewed towards small fragment size. Larger patches had a higher proportion of more hydric forest cover classes than did smaller patches which had a higher proportion of less hydric forest cover classes. Public lands accounted for 16% of remaining forested wetlands. Fewer than 100 forest patches exceeded our hypothesized habitat objective (4000 ha minimum contiguous forest area) intended to support self-sustaining populations of forest breeding birds. To increase the number of forest patches exceeding 4000 ha contiguous area, and thereby increase the likelihood of successful forest bird conservation, we recommend afforestation adjoining existing forest fragments ≥1012 ha and focused within designated Forest Bird Conservation Regions. Abstract Que sabe las caracteristicas actuales de la distribucion y de la talla del fragmento del bosque es integral al desarrollo de los objetivos geograficamente definido, habitat basado de la conservacion para criar pajaros. Hacia este extremo, clasificamos 2,6 millones de has de la cubierta del bosque dentro del valle aluvial de Mississippi usando 1992 imagenes basadas en los satelites del mapper tematico. Aunque historicamente sigue habiendo esta area, de Illinois meridional a Louisiana meridional, fue dominada cerca bosques de maderas dura inundable, cubierta del bosque en menos que 25% del esta valle. La cubierta restante del bosque se abarca de los fragmentos discretos > 2 ha del bosque > 38 000. Area de fragmento malo (64,1±5,2 ha; x±SE) fue sesgado altamente hacia talla pequena del fragmento. Fragmentos mas grandes tenian una parte mas elevada de clases mas hidricas de la cubierta del bosque que fragmentos mas pequenos que teniian una parte mas elevada de clases menos hidricas de la cubierta del bosque. Las pistas publicas consideraron 16% de restante bosques inundable. Menos de 100 fragmentos del bosque excedieron nuestro objetivo presumido del habitat (4000 ha area contigua minima del bosque) prevista para utilizar las poblaciones independientes economicamente del bosque que crian pajaros. Para aumentar el numero de los fragmentos del bosque que exceden 4.000 has de area contigua, y de tal modo para aumentar la probabilidad de la conservacion acertada del pajaro del bosque, recomendamos la repoblacion forestal que el bosque existente colindante hace fragmentos de ≥1012 ha y que enfocado dentro de regiones senaladas de la conservacion del pajaro del bosque.