Parkland Trees under Severe Drought: An Assessment of Species Diversity and Abundance across Three Agroecological Zones of Northern Nigeria

Abstract

The appraisal of tree stand structure on parklands is crucial for sustainable agroforestry management decisions, particularly in the drylands of Nigeria. An assessment of tree species distribution in farm plots across the three driest Agroecological zones (AEZ) within Northern Nigeria was performed to determine diversity and abundance in a changing climate. The AEZ include Sudan savannah (SS), Northern Guinea savannah (NGS) and Southern Guinea savannah (SGS). In each AEZ, 3 transects were laid per village and a total of 4 sample plots were located along each transect. Tree bole diameter of all the sampled woody perennials with dbh ≥ 10 cm was measured and identified to species level. The measurement and computation include basal area, species relative density and dominance as well as the important value index (IVI). Results showed that across the AEZs, Parkia biglobosa trees had the highest IVI but reduces from the driest zone, SS (50.25%) through the transitional zone, NGS (38.45%) to the wettest AEZ, the SGS (35.43%). The lowest IVI recorded were in Gliricidia sepium (0.62%), Psidium guajava (2.89%) and Eucalyptus camaldulensis (1.83) in the SGS, NGS and SGS respectively. Parkia biglobosa and Mangifera indica dominated the landscapes and are classified as the landscapes' habitat generalists. Despite the low organic matter content, Sudan savannah had more diverse species on its farm landscapes than the two other AEZ but with less tree popuplation density. The potential contribution of agroforestry parkland trees to agrobiodiversity in reducing drought and improving soil fertility is essential for sustainable agricultural productivity and landscape restoration.

Abundance and Diversity of Pleurotus Species and Host Trees for Sustainable Management in Ngel-Nyaki Montane Forest Ecosystem

“…Shannon-Wiener Diversity Index, H': Where: H' = Shannon-Weiner diversity index S = Total number of species in the community Pi = Proportion of S made up of the i th species ln = natural logarithm. Species richness (SR) was calculated as follows: TS ÷ TA ………………….. (3) Where: TS = Total number of species while TA = Total area covered as adopted from [41].…”

The Role of Precipitation in Sustainable Water Management: Insights from Atmospheric Science

“…• As one proceeds north, the tall trees of the Guinea savannah give way to shrubs and shorter trees. Rainfall is decreased and the environment is less humid (Abdullahi, 2020). From Enugu, which is close to the south, through Kaduna, the climate and grassland stretch with less trees and less rainfall.…”

Multiple-year farm-level assessments of trade-offs between GHG emissions and income: case examples of two farming systems in Northern Nigeria

“…Bunkure Local Government Area (LGAs) in Kano State was randomly selected due to the homogeneity of tree, crop and livestock production systems in the LGAs of Kano. Maigateri LGA in Jigawa State was purposively selected as an area with representative current tree, crop and livestock production practices, and due to the large number of livestock and its proximity to Zinder region in the Republic of Niger where successful climatesmart technologies were already established (Abdullahi, 2021;Carsan et al, 2014;Reij & Smaling, 2008). Both LGAs are characterized by numerous smallholder farms that integrate grain (sorghum) and legume crops (soybean and groundnut), trees African Locust Bean (Parkia biglobosa) and Camel's Foot (Piliostigma reticulatum), and multiple livestock species (cattle, goats and sheep).…”