Understanding the Biodiversity Contributions of Small Protected Areas Presents Many Challenges
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land Perspective Understanding the Biodiversity Contributions of Small Protected Areas Presents Many Challenges Robert F. Baldwin * and Nakisha T. Fouch Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-864-656-1976 Received: 27 September 2018; Accepted: 18 October 2018; Published: 20 October 2018 Abstract: Small protected areas dominate some databases and are common features of landscapes, yet their accumulated contributions to biodiversity conservation are not well known. Small areas may contribute to global biodiversity conservation through matrix habitat improvement, connectivity, and preservation of localized ecosystems, but there is relatively little literature regarding this. We review one database showing that the average size of nearly 200,000 protected areas in the United States is ~2000 ha and the median is ~20 ha, and that small areas are by far the most frequent. Overall, 95% and 49% of the records are less than the mean (1648 ha) and median (16 ha), respectively. We show that small areas are prevalent features of landscapes, and review literature suggesting how they should be studied and managed at multiple scales. Applying systematic conservation planning in a spatially hierarchical manner has been suggested by others and could help insure that small, local projects contribute to global goals. However, there are data and financial limitations. While some local groups practice ecosystem management and conservation planning, they will likely continue to protect what is “near and dear” and meet site-based goals unless there is better coordination and sharing of resources by larger organizations. Keywords: conservation landscapes; scale of assessment; conservation planning 1. Introduction There is wide agreement that the biodiversity crisis is best met with a carefully planned system of large conservation areas within well-connected networks [1]. However, humanity did not act in a concerted, globally-minded fashion to produce a functional system that protects biodiversity. Rather, what exists on the landscape is a distribution of conserved parcels with histories related as much to aesthetics and socioeconomic convenience as to systematic scientific goals [2,3]. There has been much research examining the effectiveness of the protected areas’ estate. There is a preponderance of literature concluding that protected areas’ coverage is inadequate, spatial distributions are biased, edge effects are eroding interior conditions, and that there is poor governance resulting in alienation of local human populations [4–6]. There is less understanding of how these negative conditions might be ameliorated by very local actions, resulting in a matrix of improved landscape conditions and more engaged conservation constituents [7,8]. An area of research that needs attention is the landscape-level function and roles played by the plethora of very small protected areas, although marine protected areas have received more attention [9]. In fact, there is little descriptive information revealing the dominance by frequency across the land surface of small areas. To that end, we will briefly review one dataset—the Protected Areas Database of the United States—as to size distributions, and then discuss broader conservation issues concerning small areas. Throughout, we make recommendations for further research. Land 2018, 7, 123; doi:10.3390/land7040123 www.mdpi.com/journal/land Land 2018, 7, 123 2 of 12 The Protected Areas Database of the United States V1.4 (PADUS) has 194,518 parcels forLand 2018 the, 7 continental, x FOR PEER REVIEW US, including designations as local as county parks and conservation2 of 12 easements, as well as large national parks and forests [10]. The PADUS is maintained by theas large United national States parks Geological and forests Survey’s [10]. NationalThe PADUS Gap is Analysismaintained Project by the in United order States to organize Geological and assessSurvey’s the National management Gap Analysis status Project of elements in order of to biodiversity organize and projection, assess the i.e., management “protected status areas”. of Theelements database of biodiversity includes all projection, known public i.e., “protected areas and areas”. voluntarily The database provided, includes private all protected known public areas (e.g.,areas conservationand voluntarily easements). provided, Theprivate PADUS protected has versions areas (e.g., between conservation 2005 and easements). 2016, currently The PADUS at V1.4 (hashttps://gapanalysis.usgs.gov/padus/data/metadata/ versions between 2005 and ). 2016, currently at V1.4 (https://gapanalysis.usgs.gov/padus/data/metadata/).We derived simple summary statistics of the PADUS area attributes and displayed them. The medianWe derived area simple of parcels summary in the statistics PADUS of was the PADUS 16 ha, the area mean attributes was 1648and displayed ha (SD = them. 33,207.1), The andmedian the frequencyarea of parcels distribution in the PADUS is skewed was strongly 16 ha, rightthe mean (Figure was1). 1648 Small ha areas (SD were= 33,207.1), nonuniformly and the distributedfrequency distribution but present is inskewed every strongly major ecoregion right (Figure (Figure 1). Small2). There areas are were 95,116 nonuniformly parcels <16 distributed ha and 185,751but present <1648 in every ha in major size, representing ecoregion (Figure 49% and2). There 95% ofare the 95,116 count, parcels respectively. <16 ha and However 185,751 much<1648 ha they in dominatedsize, representing by count, 49% the and smallest 95% of areas the count, (<16 ha) respectively. and those <1648However ha representedmuch they dominated 0.13% and 4%by count, of the totalthe smallest area, respectively. areas (<16 ha) Acknowledging and those <1648 possible ha represented errors of 0.13% omission and 4% and of commissionthe total area, in respectively. the dataset (seeAcknowledging below), these possible descriptive errors analyses of omission serve toand illustrate commission the point in the that dataset while the(see area below), covered these is dominateddescriptive analyses by largeness, serve byto illustrate number, the most point areas that are while not the large. area This covered presents is dominated unique researchby largeness, and managementby number, most problems. areas are not large. This presents unique research and management problems. Figure 1.1. Frequency distribution of protected area parcel sizes in thethe UnitedUnited States.States. The x axis is truncated atat 20002000 haha inin order toto show thethe distribution onon thethe y axis without transforming thethe data.data. Bin count is 10 ha. Bars represent the percentage of total records smaller than the mean (95%) and median areas (49%). R version 3.4.2. As noted in their metadata, PADUS is subject to errors of omission and commission. Some of the As noted in their metadata, PADUS is subject to errors of omission and commission. Some of the errors they report are due to overlap—topology—and they mention “slivers” specifically. We observed errors they report are due to overlap—topology—and they mention “slivers” specifically. We that some of the smallest polygons in the dataset were geoprocessing artifacts, including slivers [11]. observed that some of the smallest polygons in the dataset were geoprocessing artifacts, including These were typically very small, but the smallest records in the PADUS were a relatively minor portion. slivers [11]. These were typically very small, but the smallest records in the PADUS were a relatively For example, 2.4% are <0.1 ha in size. On the other hand, many very small polygons are legitimate minor portion. For example, 2.4% are <0.1 ha in size. On the other hand, many very small polygons are legitimate conserved parcels. Many records (27,338 or 14.1%) were less than 1 ha and distinct parcels, as illustrated in Figure 3. While many of the small records have attributes indicating they are conservation easements or small parks, others may not be real or their spatial attributes may be inaccurate; investigating the characteristics of these parcels is an important research question, because while most are conserved areas, others may have inaccurate spatial information and Land 2018, 7, 123 3 of 12 conserved parcels. 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